Category Archives: Stem Cell Videos

Mesenchymal stem cells, or MSCs, are multipotent stromal cells that can differentiate into a variety of cell types,[1] including: osteoblasts (bone cells),[2]chondrocytes (cartilage cells),[3]myocytes (muscle cells)[4] and adipocytes (fat cells). This phenomenon has been documented in specific cells and tissues in living animals and their counterparts growing in tissue culture.

While the terms mesenchymal stem cell and marrow stromal cell have been used interchangeably, neither term is sufficiently descriptive:

The youngest, most primitive MSCs can be obtained from the umbilical cord tissue, namely Wharton's jelly and the umbilical cord blood. However the MSCs are found in much higher concentration in the Whartons jelly compared to the umbilical cord blood, which is a rich source of hematopoietic stem cells. The umbilical cord is easily obtained after the birth of the newborn, is normally thrown away, and poses no risk for collection. The umbilical cord MSCs have more primitive properties than other adult MSCs obtained later in life, which might make them a useful source of MSCs for clinical applications.

An extremely rich source for mesenchymal stem cells is the developing tooth bud of the mandibular third molar. While considered multipotent, they may prove to be pluripotent. The stem cells eventually form enamel, dentin, blood vessels, dental pulp, and nervous tissues, including a minimum of 29 different unique end organs. Because of extreme ease in collection at 810 years of age before calcification, and minimal to no morbidity, they will probably constitute a major source for personal banking, research, and multiple therapies. These stem cells have been shown capable of producing hepatocytes.

Additionally, amniotic fluid has been shown to be a rich source of stem cells. As many as 1 in 100 cells collected during amniocentesis has been shown to be a pluripotent mesenchymal stem cell.[9]

Adipose tissue is one of the richest sources of MSCs. There are more than 500 times more stem cells in 1 gram of fat than in 1 gram of aspirated bone marrow. Adipose stem cells are actively being researched in clinical trials for treatment of a variety of diseases.

The presence of MSCs in peripheral blood has been controversial. However, a few groups have successfully isolated MSCs from human peripheral blood and been able to expand them in culture.[10] Australian company Cynata also claims the ability to mass-produce MSCs from induced pluripotent stem cells obtained from blood cells using the method of K. Hu et al.[11][12]

Mesenchymal stem cells are characterized morphologically by a small cell body with a few cell processes that are long and thin. The cell body contains a large, round nucleus with a prominent nucleolus, which is surrounded by finely dispersed chromatin particles, giving the nucleus a clear appearance. The remainder of the cell body contains a small amount of Golgi apparatus, rough endoplasmic reticulum, mitochondria, and polyribosomes. The cells, which are long and thin, are widely dispersed and the adjacent extracellular matrix is populated by a few reticular fibrils but is devoid of the other types of collagen fibrils.[13][14]

The International Society for Cellular Therapy (ISCT) has proposed a set of standards to define MSCs. A cell can be classified as an MSC if it shows plastic adherent properties under normal culture conditions and has a fibroblast-like morphology. In fact, some argue that MSCs and fibroblasts are functionally identical.[15] Furthermore, MSCs can undergo osteogenic, adipogenic and chondrogenic differentiation ex-vivo. The cultured MSCs also express on their surface CD73, CD90 and CD105, while lacking the expression of CD11b, CD14, CD19, CD34, CD45, CD79a and HLA-DR surface markers.[16]

MSCs have a great capacity for self-renewal while maintaining their multipotency. Beyond that, there is little that can be definitively said. The standard test to confirm multipotency is differentiation of the cells into osteoblasts, adipocytes, and chondrocytes as well as myocytes and neurons. MSCs have been seen to even differentiate into neuron-like cells,[17] but there is lingering doubt whether the MSC-derived neurons are functional.[18] The degree to which the culture will differentiate varies among individuals and how differentiation is induced, e.g., chemical vs. mechanical;[19] and it is not clear whether this variation is due to a different amount of "true" progenitor cells in the culture or variable differentiation capacities of individuals' progenitors. The capacity of cells to proliferate and differentiate is known to decrease with the age of the donor, as well as the time in culture. Likewise, whether this is due to a decrease in the number of MSCs or a change to the existing MSCs is not known.[citation needed]

Numerous studies have demonstrated that human MSCs avoid allorecognition, interfere with dendritic cell and T-cell function, and generate a local immunosuppressive microenvironment by secreting cytokines.[20] It has also been shown that the immunomodulatory function of human MSC is enhanced when the cells are exposed to an inflammatory environment characterised by the presence of elevated local interferon-gamma levels.[21] Other studies contradict some of these findings, reflecting both the highly heterogeneous nature of MSC isolates and the considerable differences between isolates generated by the many different methods under development.[22]

The majority of modern culture techniques still take a colony-forming unit-fibroblasts (CFU-F) approach, where raw unpurified bone marrow or ficoll-purified bone marrow Mononuclear cell are plated directly into cell culture plates or flasks. Mesenchymal stem cells, but not red blood cells or haematopoetic progenitors, are adherent to tissue culture plastic within 24 to 48 hours. However, at least one publication has identified a population of non-adherent MSCs that are not obtained by the direct-plating technique.[23]

Other flow cytometry-based methods allow the sorting of bone marrow cells for specific surface markers, such as STRO-1.[24] STRO-1+ cells are generally more homogenous, and have higher rates of adherence and higher rates of proliferation, but the exact differences between STRO-1+ cells and MSCs are not clear.[25]

Methods of immunodepletion using such techniques as MACS have also been used in the negative selection of MSCs.[26]

The supplementation of basal media with fetal bovine serum or human platelet lysate is common in MSC culture. Prior the use of platelet lysates for MSC culture, the pathogen inactivation process is recommended to prevent pathogen transmission.[27]

Mesenchymal stem cells have been shown to contribute to cancer progression in a number of different cancers, particularly the Hematological malignancies because they contact the transformed blood cells in the bone marrow.[28]

The mesenchymal stem cells can be activated and mobilized if needed. However, the efficiency is very low. For instance, damage to muscles heals very slowly but further study into mechanisms of MSC action may provide avenues for increasing their capacity for tissue repair.[29][30]

Many of the early clinical successes using intravenous transplantation have come in systemic diseases like graft versus host disease and sepsis. However, it is becoming more accepted that diseases involving peripheral tissues, such as inflammatory bowel disease, may be better treated with methods that increase the local concentration of cells.[31] Direct injection or placement of cells into a site in need of repair may be the preferred method of treatment, as vascular delivery suffers from a "pulmonary first pass effect" where intravenous injected cells are sequestered in the lungs.[32] Clinical case reports in orthopedic applications have been published, though the number of patients treated is small and these methods still lack rigorous study demonstrating effectiveness. Wakitani has published a small case series of nine defects in five knees involving surgical transplantation of mesenchymal stem cells with coverage of the treated chondral defects.[33]

At least 218 clinical trials investigating the efficacy of mesenchymal stem cells in treating diseases have been initiated - many of which being autoimmune diseases.[34] Promising results have been shown in a variety of conditions, such as graft versus host disease, Crohn's disease, multiple sclerosis, systemic lupus erythematosus, and systemic sclerosis.[35] While their anti-inflammatory/immunomodulatory effects appear to greatly ameliorate autoimmune disease severity, the durability of these effects remain to be seen.

Scientists have reported that MSCs when transfused immediately within few hours post thawing may show reduced function or show decreased efficacy in treating diseases as compared to those MSCs which are in log phase of cell growth, so cryopreserved MSCs should be brought back into log phase of cell growth in in vitro culture before these are administered for clinical trials or experimental therapies, re-culturing of MSCs will help in recovering from the shock the cells get during freezing and thawing. Various clinical trials on MSCs have failed which used cryopreserved product immediately post thaw as compared to those clinical trials which used fresh MSCs.[36]

In 1924, Russian-born morphologist Alexander A. Maximow used extensive histological findings to identify a singular type of precursor cell within mesenchyme that develops into different types of blood cells.[37]

Scientists Ernest A. McCulloch and James E. Till first revealed the clonal nature of marrow cells in the 1960s.[38][39] An ex vivo assay for examining the clonogenic potential of multipotent marrow cells was later reported in the 1970s by Friedenstein and colleagues.[40][41] In this assay system, stromal cells were referred to as colony-forming unit-fibroblasts (CFU-f).

The first clinical trials of MSCs were completed in 1995 when a group of 15 patients were injected with cultured MSCs to test the safety of the treatment. Since then, over 200 clinical trials have been started. However, most are still in the safety stage of testing.[7]

Subsequent experimentation revealed the plasticity of marrow cells and how their fate could be determined by environmental cues. Culturing marrow stromal cells in the presence of osteogenic stimuli such as ascorbic acid, inorganic phosphate, and dexamethasone could promote their differentiation into osteoblasts. In contrast, the addition of transforming growth factor-beta (TGF-b) could induce chondrogenic markers.[citation needed]

Statistical-based analysis of MSC therapy for osteo-diseases inferred that most studies are still under investigation. There are different follow-up times that indicate we are still far from reaching the final conclusion. [42]

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Mesenchymal stem cell - Wikipedia, the free encyclopedia

Stem Cell Technology represents a major breakthrough in anti-aging and regenerative skin care, by protecting, strengthening, and replenishing our own human skin cells. Where Peptides stimulate different functions acting as messengers to skin cells, stem cell technology improves the life of the core of the cell. Working in synergy with peptides, they enhance the effectiveness of peptides and other active ingredients.

Antiaging effects - The stem cells in our skin have a limited life expectancy due to DNA damage, aging and oxidative stress. As our own skin stem cells age, they become more difficult to repair and replenish. Protection of our stem cells becomes more and more beneficial as our skin ages, and with the advent of stem cells, we are now able to delay the natural aging process even further than before.

Expected benefits of stem cells technology for regenerative skin care:

Stem Cell Replenishing Serum Featuring a potent concentration of apple and edelweiss plant stem cells, state-of-the-art peptides, and other cutting edge ingredients, the Stem Cell Replenishing Serum is thoroughly formulated to produce age defying results, restoring the youthful look and vitality to aging skin.

Stem Cell Moisturizing Cream Also featuring a healthy concentration of apple and edelweiss plant stem cells, peptides, and numerous botanical extracts, the Stem Cell Moisturizing Cream is formulated to produce age defying results while also helping to maintain healthy and youthful looking skin as a daily moisturizer.

Our Stem Cell Applications:

LPAR Stem Cell Products contain a wide variety of stem cells with healthy and potent concentrations in order to deliver the results skin care consumers strive for. The first stem cell ingredient discovered and produced is a liposomal preparation based on the stem cells of a rare Swiss apple. The revolutionary active ingredient, Malus Domestica by PhytoCellTec is based on a high tech plant cell culture technology. It has been proven to protect the longevity of skin stem cells and provide significant anti-wrinkle effects. Since the discovery and the worldwide success of Apple Stem Cells introduction to the cosmetic and skin care marketplace, other new and exciting stem cell ingredients have been discovered to provide extraordinary results for all skin types.

We were proud to be the first skin care line to offer the ground-breaking combination of Apple and Edelweiss stem cells, and are dedicated to formulating the best new and existing stem cell ingredients into our product line as the technology continues to develop.

To inquire about purchasing LPAR Stem Cell products. visit our Retail Locator page.

Featuring a luxurious and potent blend of three major botanical stem cells (Apple, Gardenia Jasminoides, Echinacea Angustifolia) two state-of-the-art peptides (Nutripeptides, Matrixyl synthe6), and numerous botanical extracts and minerals, the Stem Cell Nourishing Mask is thoroughly formulated to nourish, firm, and energize mature skin. Total Stem Cell Concentration: 5.5% - Total Peptide Concentration: 9.0%

Directions: Using fingertips, apply on clean, dry skin twice weekly. Avoid the eye area. The mask can be left on the skin for prolonged periods (during the day or overnight). Allow at least 10-15 minutes for the mask to penetrate the skin before rinsing with water or applying additional product For external use only.

Ingredients: Water (Aqua), Glycerin, Glyceryl Acrylate/Acrylic Acid Copolymer, Hydrolyzed Rice Protein (Nutripeptides), Sodium Hyaluronate, Hydroxypropyl Cyclodextrin, Palmitoyl Tripeptide-38 (Matrixyl synthe6), Biosaccharide Gum-1, Olea Europaea (Olive) Fruit Oil, Gardenia Jasminoides Meristem Cell Culture, Xanthan Gum, Malus Domestica Fruit Cell Culture, Lecithin, Porphyridium Polysaccharide, Echinacea Angustifolia Meristem Cell Culture, Carbomer, Triethanolamine, Mentha Pipertita (Peppermint) Extract, Camellia Sinensis (Green Tea) Leaf Extract, Palmaria Palmata (Dulce) Extract, Chamomilla Recutita (Matricaria) Flower Extract, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Copper PCA, Zinc PCA, Dipotassium Glycyrrhizate, Olea Europaea (Olive) Fruit Extract, Aloe Barbadensis Leaf Juice Powder, Fragrance (Parfum)

Featuring a plant and fruit stem cell enhanced blend of three major stem cells (Apple, Edelweiss, Alpine Rose), state-of-the-art peptides (Eyeseryl, Nutripeptides), the Stem Cell Eye Therapy is an advanced eye formula designed to nourish, firm, and increase skin elasticity and skin smoothness around the eye area. Total Stem Cell Concentration: 6.75% - Total Peptide Concentration: 11.0%

Directions: Using fingertips, apply product around both eyes on clean, dry skin once or twice daily before applying a moisturizer or night cream. For external use only.

Ingredients: Water, Acetyl Tetrapeptide-5 (Eyeseryl), Sodium Hyaluronate, Hydrolyzed Rice Protein (Nutripeptides), Glycerin, Leontopodium Alpinum Meristem Cell Culture (Edelweiss Stem Cells), Xanthan Gum, Malus Domestica Fruit Cell Culture (Apple Stem Cells), Lecithin, Porphyridium Polysaccharide, Camellia Sinensis (Green Tea) Leaf Extract, Cucumis Sativus (Cucumber) Fruit Extract, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Carbomer, Triethanolamine, Rhododendron Ferrugineum Leaf Cell Culture Extract (Alpine Rose Stem Cells) Isomalt, Sodium Benzoate, Lactic Acid, Sodium Polystyrene Sulfonate, Allantoin, Copper PCA, Aloe Barbadensis Leaf Juice Powder

Plant stem cells represent a major breakthrough in skin care, launching the beginning of a new system of treating the skin...by protecting and replenishing the building blocks of what makes up our own skin: Stem Cells. Rather than working around the natural aging process of our skin stem cells, we now have the technology available to improve the life of our skins most important and central component.

Featuring a potent combination of apple, edelweiss, and grape stem cells, state-of-the-art peptides, and other cutting edge ingredients, the Stem Cell Replenishing Serum is thoroughly formulated to produce age defying results, restoring the youthful look and vitality to aging skin.

Directions: Apply with fingertips on clean, dry skin once or twice daily. Avoid the eye area by approximately 1 cm. Suitable for mature skin types. For external use only.

Ingredients: Water (Aqua), Glycerin, Dipeptide Diaminobutyroyl Benzylamide Diacetate, Acetyl Octapeptide-3, Malus Domestica Fruit Cell Culture (Apple Stem Cells), Hydrolyzed Ceratonia Siliqua Seed Extract, Palmitoyl Tripeptide-5, PEG-8 Dimethicone, Saccharide Isomerate, Imperata Cylindrica (Root) Extract, Polysorbate 20, Leontopodium Alpinum Meristem Cell Culture (Edelweiss Stem Cells), Leucojum Aestivum Bulb Extract, Triethanolamine, Carbomer, Xanthan Gum, Vitis Vinifera Fruit Cell Extract (Grape Stem Cells), Isomalt, Sodium Benzoate, Lecithin, Disodium EDTA, Allantoin, Aloe Barbadensis Leaf Juice Powder, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, PEG-8-Carbomer, Fragrance (Parfum)

Plant stem cells represent a major breakthrough in skin care, launching the beginning of a new system of treating the skin...by protecting and replenishing the building blocks of what makes up our own skin: Stem Cells. Rather than working around the natural aging process of our skin stem cells, we now have the technology available to improve the life of our skins most important and central component.

Featuring a healthy concentration and a diverse group of stem cells (apple, edelweiss, grape), peptides, and numerous botanical extracts, the Stem Cell Moisturizing Cream is formulated to produce age-defying results, while also helping to maintain healthy and youthful looking skin as a daily moisturizer.

Directions: For mature skin and/or skin conditioning, apply onto clean, dry skin with fingertips once daily. Avoid the eye. For external use only.

Ingredient Highlights: Plant/Fruit Stem Cells 4% - Malus Domestica (Apple Stem Cells) - Leontopodium Alpinum Cell Culture Extract (Edelweiss Stem Cells) - Vitis Vinifera Fruit Cell Extract (Grape Stem Cells)

Ingredients: Water (Aqua), Glycerin, Isopropyl Myristate, Caprylic/Capric Triglyceride, Cetearyl Olivate, Sorbitan Olivate, Sorbitol, Saccharide Isomerate, Sodium Hyaluronate, Leucojum Aestivum Bulb Extract, Malus Domestica Fruit Cell Extract (Apple Stem Cells), Leontopodium Alpinum Meristem Cell Culture (Edelweiss Stem Cells), Vitis Vinifera Fruit Cell Extract (Grape Stem Cells), Crambe Abyssinica Seed Oil, Dimethicone, Cetyl Alcohol, Imperata Cylindrica (Root) Extract, Acetyl Octapeptide-3 (SNAP-8), Dipeptide Diaminobutyroyl Benzylamide Diacetate(SYN-AKE), Palmitoyl Tripeptide-3 (SYN-COL), Hydrolyzed Ceratonia Siliqua Seed Extract, Aloe Barbadensis Leaf Juice Powder, Olea Europaea (Olive) Leaf Extract, Glyceryl Stearate, Xantham Gum, Cetyl Palmitate, Sorbitan Palmitate, Bisabolol, Tocopheryl Acetate, Fragrance, Phenoxyethanol, Caprylyl Glycol, Ethylhexyglycerin, Hexylene Glycol, PEG-8, Carbomer, Lecithin, Isomalt, Sodium Benzoate, Disodium EDTA

[ pH: 5.00 ]

Featuring high concentrations of Vitamin C (Tetrahexyldecyl Ascorbate), Orange Stem Cells, and Peptides, this is a multi-beneficial cream with state-of-the-art actives formulated to deliver significant and lasting results.

Tetrahexyldecyl Ascorbate is a stable, oil soluble form of Vitamin C that penetrates deeper into the skin than traditional ascorbic acid based Vitamin C. It's a proven skin lightener, a powerful Anti-Oxidant, DNA protector, and increases collagen synthesis more effectively than ascorbic acid. Orange Stem Cells work to increase elasticity and skin resistance to the dermis, which increase firmness and diminish wrinkles while also working synergistically with peptides to further increase skin elasticity and collagen support.

How to Use: Smooth a pearl sized drop onto the face once daily (morning or evening). Avoid the eye area while applying. Follow with Solar Protection if used during the day.

Ingredients: Water (Aqua), Tetrahexyldecyl Ascorbate (Vitamin C Ester), Glycerin, Hexyl Laurate, Caprylic/Capric Triglyceride, Butylene Glycol, Sorbitol, Stearic Acid, Glyceryl Stearate, PEG-100 Stearate, Cetyl Alcohol, Sorbitan Stearate, Polysorbate 60, Acetyl Hexapeptide-8, Sodium Hyaluronate, Squalane, Dimethicone, PPG-12/SMDI Copolymer, Citrus Aurantium Dulcis Callus Culture Extract (Orange Stem Cells), Tocopheryl Acetate, Cetearyl Ethylhexanoate, Linoleic Acid, Glycine Soja (Soybean) Sterols, Phospholipids, Di-PPG-2 Myreth-10 Adipate, Retinol, Polysorbate 20, Hydrolyzed Glycosaminoglycans, Alcohol, Ectoin, Lecithin, Cyclotetrapeptide-24 Aminocyclohexane Carboxylate, Glucosamine HCl, Algae Extract, Yeast Extract, Urea, Micrococcus Lysate, Plankton Extract, Arabidopsis Thaliana Extract, Magnesium Aluminum Silicate, Xanthan Gum, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Disodium EDTA, Citrus Aurantium Dulcis (Orange) Peel Oil

[ pH: 4.7 ]

The Vitamin C Stem Cell Mask combines a potent blend of Vitamin C Ester (Tetrahexyldecyl Ascorbate), highly concentrated plant and fruit stem cells (Argan, Sea Fennel), and Aldenine, a unique peptide that acts as a cellular detoxifier and a collagen III booster.

Directions: Apply on clean, dry skin. Avoid the eye area. The mask may be left on the skin (i.e. during the day or overnight), or it may be rinsed off with lukewarm water after 10 - 15 minutes. Suitable for mature skin types.

Ingredients: Water (Aqua), Tetrahexyldecyl Ascorbate, Kaolin, Glycerin, Glyceryl Stearate, Sorbitan Olivate, Cetearyl Olivate, Cetyl Palmitate, Sorbitol, Sorbitan Palmitate, Stearic Acid, Caprylic/Capric Triglyceride, Cyclopentasiloxane, Cyclhexasiloxane, Carthamus Tinctorius (Safflower) Seed Oil, Punica Granatum Extract, Butylene Glycol, Ananas Sativus (Pineapple) Fruit Extract, Carica Papaya Fruit Extract, Hydrolyzed Wheat Protein, Hydrolyzed Soy Protein, Tripeptide-1, Argania Spinosa (Argan Stem Cells) Sprout Cell Extract, Crithmum Maritimum (Sea Fennel Stem Cells) Callus Culture Filtrate, Oligopeptide-68, Sodium Oleate, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Polyacrylamide, C13-14 Isoparaffin, Laureth-7, Isomalt, Hydrogenated Lecithin, Lecithin, Sodium Benzoate, Allantoin, Citrus Aurantium Dulcis (Orange) Peel Oil, Magnesium Aluminum Silicate, Xanthan Gum, Disodium EDTA

[ pH: 6.00 ]

Originally designed to prepare and increase the skins receptiveness to our Professional Peptide Peel, the Premier Peptide Serum has gone on to become our most powerful anti-wrinkle product for year-round home care due to its high concentration and diversity of peptides. Composed of a total concentration of 65% peptides, the Premier Peptide Serum is a state of the art facial serum expertly formulated to reduce the signs of aging, energizing mature skin.

The Intensive Clarifying Peptide Cream is a unique and high potency moisturizing cream formulated with an abundance of natural skin lighteners, peptides, and botanical extracts that combine to clarify and firm mature skin, while effectively minimizing fine lines and wrinkles.

The Collagen Peptide Complex builds off of our original Collagen Copper Activating Complex, and includes an advanced formulation of peptides, including Syn-Coll, a small but powerful peptide that stimulates collagen synthesis at a cellular level, helping to compensate for any collagen deficit in the skin.

Boasting a remarkable collection of natural and innovative ingredients from exotic plants and enhanced peptides, the neck firming cream has been designed & tested to firm and energize mature skin, while providing increased smoothness and elasticity to the often neglected neck area.

Providing sufficient hydration is the most essential way to keep our skin healthy and youthful. While many of our products assist in hydrating the skin, hydration is the main focus of the Nano-Peptide B5 Complex, acting as the foundation for your home care regimen. Fortified with Sodium Hyaluronate (30%) and Pantothenic acid, it provides an especially deep and complete hydration. Because of the presence of peptides, it also assists in tightening and firming the skin while allowing for maximum absorption and effectiveness.

Designed for mature skin, this sophisticated moisturizer promotes cell renewal, stimulating the dermis layer of the skin with a high potency blend of peptides (Argireline, Matrixyl, & Biopeptide-CLTM) and botanical extracts that make it a particularly refined and effective moisturizing cream for age management.

The A&M Eye Recovery Therapy is an advanced age management treatment, applying the most tried and true peptides and delivery systems; Argireline & Matrixyl, to the highly wrinkle prone and fragile eye area, providing diminished wrinkle depth, and increased firmness and elasticity. The peptide Eyeliss is added to further enhance this treatment by counteracting skin slackening, puffiness, and decreasing irritation.

The A&M Facial Recovery Therapy is an advanced age-management treatment that blends the most tried and true peptides and delivery systems; Argireline & Matrixyl. Stimulating the deeper layers of the skin, the A&M Facial Recovery Therapy provides diminished wrinkle depth, as well as an increase in skin elasticity and firmness.

Originally designed to prepare and increase the skins receptiveness to our Professional Peptide Peel, the Premier Peptide Serum has gone on to become our most powerful anti-wrinkle product for year-round home care due to its high concentration and diversity of peptides. Composed of a total concentration of 65% peptides, the Premier Peptide Serum is a state of the art facial serum expertly formulated to reduce the signs of aging, energizing mature skin.

Directions: For mature skin types; apply at least three weeks before beginning the Lucrece Professional Peptide Peel treatment, and use twice a day leading up to the Peel. For year round application, apply once per day after the Collagen Peptide Complex. Avoid the eye area by at least 1 cm during application.

Peptides: SYN-AKE: A small peptide (Dipeptide Diaminobutyroyl Benzylamide Diacetate) that mimics the activity of Waglerin 1, a polypeptide that is found in the venom of the Temple Viper, Tropidolaemus wagleri. Clinical trials have shown SYN-AKE is capable of reducing wrinkle depth by inhibiting muscle contractions. SNAP-8: An anti-wrinkle (Acetyl Octapeptide-3) elongation of the famous Hexapeptide Argireline. The study of the basic biochemical mechanisms of anti-wrinkle activity led to the revolutionary Hexapeptide which has taken the cosmetic world by storm. ARGIRELINE: (Acetyl Hexapeptide-8) MATRIXYL: (Palmitoyl Pentapeptide-4) REGU-AGE: (Hydrolyzed Rice Bran Protein - Oxido Reductases - Soybean Protein) BIOPEPTIDE CL: (Palmitoyl Oligopeptide) RIGIN: (Palmitoyl Tetrapeptide-7) EYELISS: (Dipeptide-2 & Palmitoyl Tetrapeptide-7) INYLINE: (Acetyl Hexapeptide 30)

Other Ingredients: Water, Sodium Hyaluronate, Spiraea Ulmaria Flower Extract & Centella Asiatica Extract & Echinacea Purpurea Extract, Phenoxyethanol & Benzyl Alcohol & Potassium Sorbate & Tocopherol, Meadowsweet, Hydrocotyl Extract, Leucojum Aestivum Bulb Extract, Amino Acids, Diazolidinyl Urea, Imperata Cylindrica Extract, SMDI Copolymer, Hydroxyethylcellulose

[ pH: 5.00 ]

This unique and high potency moisturizing cream is formulated with an abundance of natural skin lighteners, peptides, and botanical extracts that combine to help clarify and energize mature skin.

Directions: Smooth a pearl size drop onto the face, gently massaging in with fingertips once per day (morning), avoiding the eye area. Follow with solar protection if applicable.

Skin Lightening Agents: Mulberry Bark, Saxifrage Extract, Grape Extract, Scutellaria Root Extracts, Vitamin C Ester (Tetrahexyldecyl Ascorbate), Emblica Fruit Extract, Licorice Root Extract.

Ingredients: Water (Aqua), Saxifrage Extract & Grape Extract & Butylene Glycol & Water & Mulberry Bark Extract & Scutellaria Root Extract, Prunus Amygdalus Dulcis (Sweet Almond) Oil, Caprylic/Capric Triglycerides, Sesamum Indicum (Sesame) Seed Oil, Cetearyl Olivate & Sorbitan Olivate, Glycerin, Palmitoyl Pentapeptide-4 (Matrixyl), Tetrahexyldecyl Ascorbate (C-Ester), Glyceryl Stearate & PEG 100 Stearate, Stearic Acid, Theobroma Cocao (Cocoa) Seed Butter, PPG-12/SMDI Copolymer, Butyrospermum Parkii (Shea) Butter, Tocopheryl Acetate (Vitamin E), Phyllanthus Emblica Fruit Extract, Palmitoyl Tripeptide-5 (Syn-Coll), Triethanolamine, Phenoxyethanol, Mangifera Indica (Mango) Seed Butter, Darutoside, Tricholoma Matsutake Singer (Mushroom) Extract, Imperata Cylindrica (Root) Extract, Fragrance (Parfum), Glucosamine HCL & Algae Extract & Yeast Extract & Urea, Retinyl Palmitate (Vitamin A), Centella Asiatica Extract & Echinacea Purpurea Extract, Xanthan Gum, Arctostaphylos Uva Ursi Leaf Extract, Glycyrrhiza Glabra Root Extract, Magnesium Aluminum Silicate, Disodium EDTA

[ pH: 5.75 ]

Specializing in firming the skin, the Collagen Peptide Complex builds off of our original Collagen Copper Activating Complex, and adds a combination of (5) major peptides, helping to keep the skin looking its youngest and most alive, as it works to firm, and add elasticity & texture to the skin. For best results, apply directly after the Nano-Peptide B5 Complex.

Directions: Apply a liberal amount on clean, dry face using fingertips, and massage into the skin. Let dry, and follow with a moisturizer and sun-block if used during the day, or the Vitamin A Facial Cream + III if used at night. Warning: For mature skin only. If redness occurs, lessen use to once or twice per week. If reactions persist, discontinue use.

Ingredients: Water (Aqua), Dipalmitoylhydroxyproline, Glycerin, Palmitoyl Tetrapeptide-7 (Rigin), Palmitoyl Oligopeptide (Biopeptide-CL), Butylene Glycol, Yeast (Faex Extract), Hydrocotyl Extract & Coneflower Extract, Aloe Barbadensis Leaf Extract, Palmitoyl Tripeptide-5 (Syn-Coll), Acetyl Hexapeptide-8 (Argireline), Palmitoyl Pentapeptide-4 (Matrixyl), Panthenol, Phenoxyethanol & Caprylyl Glycol & Ethylhexylglycerin & Hexylene Glycol, Triethanolamine, Carbomer, Decarboxy Carsonine HCI, Citrus Grandis (Grapefruit) Seed Extract, Copper PCA, Olea Europaea (Olive) Leaf Extract, Disodium EDTA

[ pH: 5.50 ]

Boasting a remarkable collection of natural and innovative ingredients from exotic plants and enhanced peptides, the neck firming cream has been designed & tested to firm and energize mature skin, while providing increased smoothness and elasticity to the often neglected neck area.

Directions: On clean dry skin, apply onto the neck area with fingertips in an upward motion. Apply twice a day, or as needed.

Key Ingredients: Bio-Bustyl: Stimulates cell metabolism, promotes collagen synthesis, and enhances fibroblast (collagen-producing cell) proliferation. INCI: Glyceryl Polymethacrylate, Soy Protein Ferment, PEG-8, & Palmitoyl Oligopeptide Polylift: Using a cross-linking technology, biopolymerization, Polylift reinforces the natural lifting effect of sweet almond proteins, providing a smooth firmness & radiance to the surface of the skin. INCI: Prunus Amygdalus Dulcis (Sweet Almond) Seed Extract.

Ingredients: Deionized Water, Prunus Amygdalus Dulcis (Sweet Almond Oil), Caprylic/Capric Triglycerides, Sesamum Indicum (Sesame) Seed Oil, Simmondsia (Jojoba) Seed Oil/ Buxus Chinensis, Cetearyl Alcohol, Dicetyl Phosphate, Ceteth-10 Phosphate, Palmitoyl Oligopeptide, Palmitoyl Tetrapeptide-7, Prunus Amygdalus Dulcis Seed Extract, Terminalia Catappa Leaf Extract & Sambucus Nigra Flower Extract & PVP & Tannic Acid, Glyceryl Polymethacrylate & Rahnella/ Soy Protein Ferment & PEG-8 & Palmitoyl Oligopeptide, Glycerin, Glyceryl Stearate & PEG 100 Stearate, Biosaccharide Gim-1, PPG-12/ SMDI Copolymer, Phyllanthus Emblica Fruit Extract, Stearic Acid, Centella Asiatica Extract & Darutosidetriethanolamine, Tocopheryl Acetate, Magnifera Indica (Mango) Seed Butter, Glycerin & Aqua & Lysolecithin & Perilla Frutescens Seed Oil, Xantham Gum, Retinyl Palmitate, Tetrahexyldecyl Ascorbate (Vitamin C Ester), Echinacea Purpurea Extract, Imperata Cylindrica (Root) Extract, Glycyrrhiza Glabra Root Extract, Magnesium, Aluminum Silicate, Disodium EDTA

[ pH: 6.25 ]

Hydration is the most essential way to keep our skin healthy feeling and healthy looking. While many of our products assist in hydrating the skin, hydration is the main focus for this product, making it an essential for all skin types. Fortified with Hyaluronic (30%) and Panthenol (Vitamin B5), the Nano-Peptide B5 Complex provides an especially deep and complete hydration. With the addition of peptides, it also assists in tightening and firming the skin while allowing for maximum absorption and effectiveness.

The Nano-Peptide B5 Complex should be applied directly after cleansing the skin, as the 2nd step in skin care regimens for all skin types (morning & night). For best results, age management regimens should follow with the Stem Cell Replenishing Serum and/or the Collagen Peptide Complex before moisturizing.

Directions: Apply a healthy amount on clean, dry skin. May be used around the eye area.

Key Ingredients: Palmitoyl Pentapeptide-4: Stimulates the skins fibroblasts to rebuild the extra-cellular matrix, including the synthesis of Collagen I and Collagen IV, fibronectin and of Glycosaminoglycans. It also stimulates the production of the dermal matrix (Collagen I & III) resulting in a significant reduction of wrinkles and fine lines. Acetyl Hexapeptide-8: Reduces facial wrinkle depth and the signs of skin aging resulting from facial movements and facial muscle contraction by halting the release of neurotransmitters from SNARE and catecholamine complexes, (which can also induce formation of wrinkles and fine lines to the skin). Hyaluronic Acid (30%): Penetrates deep into the skin, providing ample moisture Panthenol: Enhances formation of skin pigments for younger looking skin, and contains deep penetrating properties that allow a more complete hydration.

Other Ingredients: Water (Aqua), Hyaluronic Acid, Panthenol (Vitamin B5), MDI Complex, Palmitoyl Pentapeptide-4, Acetyl Hexapeptide-8, Phenoxyethanol, Hydrolyzed Wheat Protein, Butylene Glycol, Hydrocotyl & Coneflower Extract, Glycosaminoglycans.

[ pH: 5.5 ]

Designed for mature, sun damaged, and/or dehydrated skin, the Anti-Wrinkle Facial Cream is a peptide enriched moisturizer focused on increasing skin firmness & elasticity, and fortifying the skin with anti-oxidants & botanical extracts to facilitate healthy feeling and healthy looking skin.

Directions: Smooth a pearl size drop onto the face, massage into skin thoroughly. For use in the morning (recommended), follow with solar protection.

Ingredients: Water (Aqua), Glycerin, Dimethicone, Caprylic/Capric Triglycerides, C12-15 Alkyl Benzoate, Linoleic Acid & Glycine Soja (Soybean) Sterols & Phospholipids, Acetyl Hexapeptide-8, Butylene Glycol & Carbomer & Polysorbate 20 & Palmitoyl Pentapeptide-4, Cetearyl Alcohol & Dicetyl Phosphate & Ceteth-10 Phosphate, Glyceryl Stearate & PEG 100 Stearate, PPG-12/ SMDI Copolymer, Phyllanthus Emblica Fruit Extract, Darutoside, Cocoa Butter, Cetyl Alcohol, Butyrospermum Parkii (Shea Butter), Saccharomyces/Xylinum Black Tea Ferment & Glycerin & Hydroxyethylcellulose, Glucoseamine HCL & Algae Extract & Saccharomyces Cerevisiae (Yeast Extract) & Urea, Steareth-20 & Palmitoyl Tetrapeptide-7, Centella Asiatica Extract & Echinacea Purpurea Extract, Hydrolyzed Vegetable Protein, Imperata Cylindrica (Root) Extract & PEG-8 & Carbomer, Phenoxyethanol & Caprylyl Glycol & Ethylhexylglycerin & Hexylene Glycol, Polyglyceryl Methacrylate & Propylene Glycol & Palmitoyl Oligopeptide, Cyclopentasiloxane & Dimethicone, Stearic Acid, Mangifera Indica (Mango) Seed Butter, Tocopheryl Acetate, Glycyrrhiza Glabra Root Extract, Arctostaphylos Uva Ursi Leaf Extract, Chlorella Vulgaris Extract, Corallina Officinalis Extract, Dipotassium Glycyrrhizate, PEG-8 & Tocopherol & Ascorbyl Palmitate & Ascorbic Acid & Citric Acid, Disodium EDTA, Magnesium Aluminum Silicate, Xanthan Gum, Triethanolamine, Retinyl Palmitate, Lavandula Angustifolia (Lavender) Oil

[ pH: 5.75 ]

This advanced eye care treatment is expertly formulated to diminish the depth, increase firmness & elasticity, and to counteract skin slackening to the highly wrinkle prone and fragile eye area. Featuring (4) major peptides (Argireline, Matrixyl, Eyeliss, & Regu-age), the A&M Eye Recovery Therapy is our most potent eye treatment, and is recommended for mature skin.

Directions: Using fingertips, massage to surrounding eye areas affected by wrinkles due to muscle contractions. Also use in the nasal labial area. For best results, apply once per evening, followed by the A&M Facial Recovery Therapy, and/or the Vitamin A Facial Cream + III.

Ingredients Highlights: Palmitoyl Pentapeptide-4 (Matrixyl): Stimulates the skins fibroblasts to rebuild the extra-cellular matrix, including the synthesis of Collagen I and Collagen IV, fibronectin and of Glycosaminoglycans. It also stimulates the production of dermal matrix (Collagen I & III) resulting in a significant reduction of wrinkles and fine lines of the skin. Acetyl Hexapeptide-8 (Argireline): Reduces facial wrinkle depth and the signs of skin aging resulting from facial movements and facial muscle contraction by halting the release of neurotransmitters from SNARE and catecholamine complexes, (which can also induce formation of wrinkles and fine lines to the skin). Dipeptide-2 & Palmitoyl Tetrapeptide-7 (Eyeliss): Combats the effect of tiredness and hypertension, as well as the natural effects of aging, which contribute to the formation of bags under the eyes, Eyeliss is an outstanding anti-aging ingredient. Soy Peptides & Hydrolyzed Rice Bran Extract (Regu-Age): A highly active complex of specially purified soy and rice peptides and biotechnologically derived yeast protein, Regu-Age effectively addresses dark circles and puffiness around the eyes.

Other Ingredients: Water, Sodium Hyaluronate, Centella Asiatica Extract & Echinacea Purpurea Extract, Xanthan Gum-Chondrus Crispus & Glucose, Lecithin & Dipalmitoyl Hydroxyproline, Imperata Cylindrica Extract, PEG-8 Dimethicone, Cyclomethicone

[ pH: 6.25 ]

An advanced age management treatment that blends the most tried and true peptides and delivery systems, Argireline & Matrixyl, helping to prevent skin aging induced by repeated facial movement caused by excessive catecholamine release. Stimulating the deeper layers of the skin, the A&M Facial Recovery Therapy provides diminished wrinkle depth, as well as an increase in the elasticity and firmness of the skin. Recommend for mature skin types.

Directions: Using fingertips apply to facial areas and massage into skin once per evening, allowing it to absorb into the skin. Apply directly after the A&M Eye Recovery Therapy.

Ingredients Highlights: Palmitoyl Pentapeptide-4: Stimulates the skins fibroblasts to rebuild the extra-cellular matrix, including the synthesis of Collagen I and Collagen IV, fibronectin and of Glycosaminoglycans. It also stimulates the production of dermal matrix (Collagen I & III) resulting in a significant reduction of wrinkles and fine lines of the skin. Acetyl Hexapeptide-8: Reduces facial wrinkle depth and the signs of skin aging resulting from facial movements and facial muscle contraction by halting the release of neurotransmitters from SNARE and catecholamine complexes, (which can also induce formation of wrinkles and fine lines to the skin).

Other Ingredients: Deionized Water, Sodium Hyaluronate, Lecithin & Dipalmitoyl Hydroxyproline, Hydrocotyl & Coneflower Extracts, Glycosaminoglycans, Glucosamine HCI & Alagae Extract & Yeast Extract & Urea, Magnesium Ascorbyl Phosphate, Glycine HCL, Retinyl Palmitate

[ pH: 6.25 ]

Addressing the multiple problems of sun and age damaged skin, the Intensive Clarifying Facial Cream + III is a glycolic acid based moisturizer featuring three potent skin lighteners; Kojic Acid, Licorice, and Hydro- quinone (2%), which quickly & effectively treat hyperpigmentation & discolorations.

Vitamin C Ester (Tetrahexyldecyl Ascorbate) is a stable, oil-soluble form of Vitamin C, providing high level skin lightening, enhanced collagen synthesis, and increased DNA & UV protection with higher absorption capabilities and less irritating than Ascorbic Acid.

Because of how well it protects the skins collagen fibers, ascorbic acid based Vitamin C is widely considered one of the most effective antioxidants for skin rejuvenation & revitalization. The 20% Vitamin C Lightening drops combine a potent concentration of ascorbic acid with aloe, green tea leaf extract, and mushroom extract. *Also available is our original Vitamin C Serum, containing a milder blend of ascorbic acid (14%).

The Anti-Wrinkle Eye Cream contains a high potency blend of peptides, including EyelissTM & Regu-age (in addition to Argireline & Matrixyl) which work synergistically to improve firmness, elasticity, and reduce puffiness & dark circles around the eye area.

Addressing the multiple problems of sun and age damaged skin, the Intensive Clarifying Facial Cream + III moisturizer combines three powerful lightening. Agents: Hydroquinone, Kojic Acid, & Licorice, with Alpha Lipoic Acid, Vitamin C, & Co-enzyme Q10, minimizing fine lines, evening skin tone, and naturally exfoliating the outer layer of the skin while providing a 15 sun protection factor (SPF).

Directions: Smooth a pearl sized drop onto the face once or twice daily. Avoid eye area. If used during the day, apply additional sun protection if skin is in contact with the sun for an extended period (twenty minutes or more).

Active Ingredients: Octyl Methoxycinnamate - 7.5% Octyl Salcylate - 5% Glycolic Acid - 4% Benzophenone - 3% Hydroquinone - 2%

Inactive Ingredients: Deionized Water, Glyceryl Stearate & PEG-100 Stearate, Ascorbic Acid (Vitamin C), Alpha Lipoic Acid, Co-enzyme Q 10, Kojic Acid, Cetyl Alcohol, Licorice, Palmitic Acid, Octyl Salcylate, Phenoxyethanol, Tocopheryl Acetate, Essential Oil of Rosewood, Disodium tEDTA

[ pH: 4.5 ]

Vitamin C Ester is a stable, oil-soluble form of Vitamin C, providing high level Skin Lightening, enhanced Collagen Synthesis, and increased DNA & UV protection with higher absorption capabilities than Ascorbic Acid.

Directions: On clean, dry skin, apply four to five drops directly onto the face once a day, avoiding the eye area.

Ingredients: Cyclomethicone, Tetrahexyldecyl Ascorbate (Vitamin C Ester 10%), PPG-12/SMDI Copolymer, Santalum Album Extract, Phellodendrone Amurense Bark Extract, Barley Extract, Jojoba Seed Oil/Buxus Chinensis, Tocopheryl Acetate, Phenoxyethanol, Tricholoma Matsutake Singer (Mushroom Extract), Ascorbyl Palmitate, Bisabolol

[ pH: 7.0 ]

Ascorbic acid based Vitamin C is widely considered one of the most effective antioxidants for rejuvenating mature skin due to its ability to protect the skins collagen fibers, and for its ability to help inhibit melanin production, creating a lightening effect to the skin. The 20% Vitamin C Lightening Drops combine a potent concentration of ascorbic acid with aloe, green tea extract, and an exotic mushroom extract (Tricholoma Matsutake Singer) for additional lightening.

Directions: On clean, dry skin apply four to five drops directly onto the face once daily. Avoid the eye area. Thoroughly wash hands after use. Though a light tingling sensation is normal, if irritation (redness) results after application, discontinue or reduce the frequency of use of the product.

Ingredients: Water (Aqua), Ascorbic Acid -20%, Ethoxydiglycol, Hydroxyethylcellulose, Phenoxyethanol, Polysorbate 20, Camellia Sinensis Leaf Extract, Aloe Barbadensis Leaf Extract, Mushroom Extract (Tricholoma Matsutake Singer)-Enzymes- Alcohol, Sodium Sulfite, Disodium EDTA

[ pH: 3.00 ]

The Anti-Wrinkle Eye Cream is formulated to reduce puffiness, enhances firmness, strengthens connective tissues, and to help diminish dark circles around the eye area. In contrast to the A&M Eye Recovery Therapy, the Anti-Wrinkle Eye Cream concentrates on the upper layers of the skin, making it a great day moisturizer for the eyes.

Directions: Apply around the eye area with the ring finger once daily. For best results, follow with a moisturizer and solar protection.

Read more:
anti-aging stem cells - Lucrece

1. Introduction

Bone marrow is a complex tissue containing hematopoietic cell progenitors and their progeny integrated within a connective-tissue network of mesenchymal-derived cells known as the stroma (1). The stroma cells, or Mesenchymal stem cells (MSCs), are multi-potent progenitor cells that constitute a minute proportion of the bone marrow, represented as a rare population of cells that makes up 0.001 to 0.01% of the total nucleated cells. They represent 10-fold less abundance than the haematopoietic stem cells (2), which contributes to the organization of the microenvironment supporting the differentiation of hematopoietic cells (3). MSC are present in tissues of young, as well as, adult individuals (4, 5), including the adipose tissue, umbilical cord blood, amniotic fluid and even peripheral blood (1, 6-8). MSCs were characterized over thirty years ago as fibroblast-like cells with adhesive properties in culture (9, 10). The term MSC has become the predominant term in the literature since the early 90s (11), after which their research field has grown rapidly due to the promising therapeutic potential, resulting in an increased frequency of clinical trials in the new millennium at an explosive rate.

As data accumulated, there was a need to establish a consensus on the proper definition of the MSCs. The International Society for Cellular Therapy has recommended the minimum criteria for defining multi-potent human MSCs (12, 13). The criteria included: (i) cells being adherent to plastic under standard culture conditions; (ii) MSC being positive for the expression of CD105, CD73 and CD90 and negative for expression of the haematopoietic cell surface markers CD34, CD45, CD11a, CD19 or CD79a, CD14 or CD11b and histocompatibility locus antigen (HLA)-DR; (iii) under a specific stimulus, MSC differentiate into osteocytes, adipocytes and chondrocytes in vitro. These criteria presented properties to purify MSC and to enable their expansion by several-fold in-vitro, without losing their differentiation capacity. When plated at low density, MSCs form small colonies, called colony-forming units of fibroblasts (CFU-f), and which correspond to the progenitors that can differentiate into one of the mesenchymal cell lineages (14, 15). It has been reported lately that MSCs are able to differentiate into both mesenchymal, as well as, non-mesenchymal cell lineages, such as adipocytes, osteoblasts, chondrocytes, tenocytes, skeletal myocytes, neurones and cells of the visceral mesoderm, both in vitro and in vivo (16, 17).

All cells have half-lives and their natural expiration must be matched by their replacement; MSCs, by proliferating and differentiating, can be the proposed source of these new replacement cells as characterized in their differentiation capacity. This replacement hypothesis mimics the known sequence of events involved in the turnover and maintenance of blood cells that are formed from haematopoietic stem cells (HSCs) (18). Unlike HSCs, MSCs can be culture-expanded ex vivo in up to 40 or 50 cell doublings without differentiation (19). A dramatic decrease in MSC per nucleated marrow cell can be observed when the results are grouped by decade, thus showing a 100-fold decrease from birth to old age. Being pericytes present in all vascularized tissues, the local availability of MSC decreases substantially as the vascular density decreases by one or two orders of magnitude with age (20). In recent years, the discovery of MSCs with properties similar, but not identical, to BM-MSCs has been demonstrated in the stromal fraction of the connective tissue from several organs, including adipose tissue, trabecular bone, derma, liver and muscle (21-24). It is important to note that the origin of MSCs might determine their fate and functional characteristics (25). Studies of human bone marrow have revealed that about one-third of the MSC clones are able to acquire phenotypes of pre-adipocytes, osteocytes and chondrocytes (16). This is in concordance with data showing that 30% of the clones from bone marrow have been found to exhibit a trilineage differentiation potential, whereas the remainder display a bi-lineage (osteo-chondro) or uni-lineage (osteo) potential (26). Moreover, MSC populations derived from adipose tissue and derma present a heterogeneous differentiation potential; indeed, only 1.4% of single cells obtained from adipose-derived adult stem cell (ADAS) populations were tri-potent, the others being bi-potent or unipotent (27).

Mesenchymal Stem Cells have been shown to possess immunomodulatory characteristics, as described through the inhibition of T-cell proliferation in vitro (28-30). These observations have triggered a huge interest in the immunomodulatory effects of MSCs. The in vitro studies have been complemented in vivo, where both confirmed the immunosuppressive effect of MSC. MSC activating stimuli in vitro, appears to include the secretion of cytokines and the interaction with other immune cells in the presence of proinflammatory cytokines (Fig 1) (31). Primarily, the in vivo effect has been originally shown in a baboon model, in which infusion of ex vivoexpanded matched donor or third-party MSCs delayed the time to rejection of histo-incompatible skin grafts (29). The delay indicated a potential role for MSC in the prevention and treatment of graft-versus-host disease (GVHD) in ASCT, in organ transplantation to prevent rejection, and in autoimmune disorders. Recently, MSCs were used to successfully treat a 9-year-old boy with severe treatment-resistant acute GVHD, further confirming the potent immunosuppressive effect in humans (32). The immunosuppressive potential has no immunologic restriction, whether the MSCs are autologous with the stimulatory or the responder lymphocytes or the MSCs are derived from a third party. The degree of MSC suppression is dose dependent, where high doses of MSC are inhibitory, whereas low doses enhance lymphocyte proliferation in MLCs (33). Broadly, MSC modulate cytokine production by the dendritic and T cell subsets DC/Th1 and DC/Th2 (34), block the antigen presenting cell (APC) maturation and activation (35), and increase the proportion of CD4+CD25+ regulatory cells in a mixed lymphocyte reaction (36).

Potential mechanisms of the MSC interactions with immune cells. Mesenchymal stem cells (MSCs) can inhibit both the proliferation and cytotoxicity of resting natural killer (NK) cells, as well as, their cytokine production by releasing prostaglandin E2 (PGE2), indoleamine 2,3-dioxygenase (IDO) and soluble HLA-G5 (sHLA-G5). Killing of MSCs by cytokine-activated NK cells involves the engagement of cell-surface receptors (Thick blue line) expressed by NK cells with its ligands expressed on MSCs. MSCs inhibit the differentiation of monocytes to immature myeloid dendritic cells (DCs), bias mature DCs to an immature DC state, inhibit tumour-necrosis factor (TNF) production by DCs and increase interleukin-10 (IL-10) production by plasmacytoid DCs (pDCs). MSC-derived PGE2 is involved in all of these effects. Immature DCs are susceptible to activated NK cell-mediated lysis. MSC Direct inhibition of CD4+ T-cell function depends on their release of several soluble molecules, including PGE2, IDO, transforming growth factor-1 (TGF1), hepatocyte growth factor (HGF), inducible nitric-oxide synthase (iNOS) and haem-oxygenase-1 (HO1). MSC inhibition of CD8+ T-cell cytotoxicity and the differentiation of regulatory T cells mediated directly by MSCs are related to the release of sHLA-G5 by MSCs. In addition, the upregulation of IL-10 production by pDCs results in the increased generation of regulatory T cells through an indirect mechanism. MSC-driven inhibition of B-cell function seems to depend on soluble factors and cellcell contact. Finally, MSCs dampen the respiratory burst and delay the spontaneous apoptosis of neutrophils by constitutively releasing IL-6.

Dendritic cells have the elementary role of antigen presentation to nave T cells upon maturation, which in turn induce the proinflammatory cytokines. Immature DCs acquire the expression of co-stimulatory molecules and upregulate expression of MHC-I and II, as well as, other cell-surface markers (CD11c and CD83). Mesenchymal stem cells have profound effect on the development of DC, where in the presence of MSC, the percentage of DC with conventional phenotype is reduced, while that of plasmacytoid DC is increased, therefore biasing the immune system toward Th2 and away from Th1 responses in a PGE-2 dependent mechanism (37). Furthermore, MSCs inhibit the up-regulation of CD1a, CD40, CD80, CD86, and HLA-DR during DC differentiation and prevent an increase of CD40, CD86, and CD83 expression during DC maturation (38). When mature DCs are incubated with MSCs they have a decreased cell-surface expression of MHC class II molecules, CD11c, CD83 and co-stimulatory molecules, as well as, decreased interleukin-12 (Il-12) production, thereby impairing the antigen-presenting function of the DCs (Fig 1) (39, 40). MSCs can also decrease the pro-inflammatory potential of DCs by inhibiting their production of tumour-necrosis factor (TNF-) (40). Furthermore, plasmacytoid DCs (pDCs), which are specialized cells for the production of high levels of type-I IFN in response to microbial stimuli, upregulate production of the anti-inflammatory cytokine IL-10 after incubation with MSCs (34). These observations indicate a potent anti-inflammatory and immunoregulatory effect for MSC in vitro and potentially in vivo.

Natural killer (NK) cells are key effector cells of the innate immunity in anti-viral and anti-tumor immune responses through their Granzyme B mediated cytotoxicity and the production of pro-inflammatory cytokines (41). NK-mediated target cell lysis results from an antigen-ligand interaction realized by activating NK-cell receptors, and associated with reduced or absent MHC-I expression by the target cell (42). MSCs can inhibit the cytotoxic activity of resting NK cells by down-regulating expression of NKp30 and natural-killer group 2, member D (NKG2D), which are activating receptors involved in NK-cell activation and target-cell killing (Fig 1) (43). Resting NK cells proliferate and acquire strong cytotoxic activity when cultured with IL-2 or IL-15, but when incubated with MSC in the presence of these cytokines, resting NK-cell, as well as, pre-activated NK cell proliferation and IFN- production are almost completely abrogated (44, 45). It is worth noting that although the susceptibility of NK cells to MSC mediated inhibition is potent, the pre-activated NK cells showed more resistance to the immunosuppressive effect of MSC compared to resting NK cells (43). The susceptibility of human MSCs to NK-cell-mediated cytotoxicity depends on the low level of cell-surface expression of MHC class I molecules by MSCs and the expression of several ligands, that are recognized by activating NK-cell receptors. Autologous and allogeneic MSC were susceptible to lysis by NK cells (43), where NK cell-mediated lysis was inversely correlated with the expression of HLA class I on MSC (46). Incubation of MSCs with IFN- partially protected them from NK-cell-mediated cytotoxicity, through the up-regulation of expression of MHC-I molecules on MSCs (43). Taken together, a possible dynamic interaction between NK cells and MSC in vivo exists, where the latter partially inhibit activated MSC, without compromising their ability to kill MSC, reflecting on an interaction tightly regulated by IFN- concentration.

Neutrophils play a major role in innate immunity during the course of bacterial infections, where they are activated to kill foreign infectious agents and accordingly undergo a respiratory burst. MSCs have been shown to dampen the respiratory burst and to delay the spontaneous apoptosis of resting and activated neutrophils through an IL-6-dependent mechanism (47). MSC had no effect on neutrophil phagocytosis, expression of adhesion molecules, and chemotaxis in response to IL-8, f-MLP, or C5a (47). Stimulation with bacterial endotoxin induces chemokine receptor expression and mobility of MSCs, which secrete large amounts of inflammatory cytokines and recruit neutrophils in an IL-8 and MIF-dependent manner. Recruited and activated neutrophils showed a prolonged lifespan, an increased expression of inflammatory chemokines, and an enhanced responsiveness toward subsequent challenge with LPS, which suggest a role for MSCs in the early phases of pathogen challenge, when classical immune cells have not been recruited yet (48). Furthermore, MSC have shown the capability to mediate the preservation of resting neutrophils, a phenomenon that might be important in those anatomical sites, where large numbers of mature and functional neutrophils are stored, such as the bone marrow and lungs (49).

T-cells are major players of the adaptive immune response. After T-cell receptor (TCR) engagement, T cells proliferate and undergo numerous effector functions, including cytokine release and, in the case of CD8+ T cells (CTL), cytotoxicity. Abundant reports have shown that T-cell proliferation stimulated with polyclonal mitogens, allogeneic cells or specific antigen is inhibited by MSCs (28, 29, 50-56). The observation that MSCs can reduce T cell proliferation in vitro is mirrored by the in vivo finding through infusions of hMSCs that control GVHD following bone marrow transplantation. Nevertheless, there is no demonstrable correlation between the measured effects of MSCs in vitro and their counter effect in vivo due to the lack of universality of methodology correlating the in vitro findings with the in vivo therapeutic potential.

MSC inhibition of T-cell proliferation is not MHC restricted, since it can be mediated by both autologous and allogeneic MSCs and depends on the arrest of T-cells in the G0/G1 phase of the cell cycle (55, 57). Thus, MSCs do not promote T-cell apoptosis, but instead maintain T cell survival upon subjection to overstimulation through the TCR and upon commitment to undergo CD95CD95-ligand-dependent activation-induced cell death (57). MSC effects on T cell proliferation in vitro appear to have both contact-dependent and contact-independent components (58). Inhibition of T-cell proliferation by MSCs leads to decreased IFN- secretion in vitro and in vivo associated with increased IL-4 production by T helper 2 (TH2) cells (34, 59). Taken together, there is an implication for a shift from a pro-inflammatory state characterized by IFN- secretion to an anti-inflammatory state characterized by IL-4 secretion (Fig 1). An imperative role for effector T-cell is the MHC restricted killing of virally-infected or of allogeneic cells mediated via CD8+ CTLs, and which is down-regulated by MSC (60).

Regulatory T cells (Tregs), a subpopulation of T cells, are vital to keep the immune system in check, help avoid immune-mediated pathology and contain unrestricted expansion of effector T-cell populations, which results in maintaining homeostasis and tolerance to self antigens. Tregs are currently identified by co-expression of CD4 and CD25, expression of the transcription factor FoxP3, production of regulatory cytokines IL-10 and TGF-, and ability to suppress proliferation of activated CD4+CD25+ T cells in co-culture experiments. Differential expression of CD127 (-chain of the IL-7 receptor) enable flow cytometry-based separation of human Tregs from CD127+ non-regulatory T-cells (61). MSCs have been reported to induce the production of IL-10 by pDCs, which, in turn, trigger the generation of regulatory T cells (Fig 1) (34, 40). Furthermore, Tregs secrete TGF- and when used in vitro, TGF- in combination with IL-2 directs the differentiation of T-cells into Tregs, while Tregs suppress the proliferation of TCR-dependent proliferation of effector CD25null or CD25low T-cells in a non-autologous fashion. Also TGF- alters angiogenesis following injury in experiments using MSC (62). In addition, after co-culture with antigen-specific T-cells, MSCs can directly induce the proliferation of regulatory T-cells through release of the immunomodulatory HLA-G isoform HLA-G5 (Fig 1) (63). Taken together, MSCs can modulate the intensity of an immune response by inhibiting antigen-specific T-cell proliferation and cytotoxicity and promoting the generation of regulatory T-cells.

Antibody producing B-cells constitute the second main cell type involved in adaptive immunity. Interactions between MSCs and B-cells have produced controversial results attributable to the inconsistent experimental conditions used (31, 55, 64). Initial reports on mice suggested that MSC exercise a dampening effect on the proliferation of B-cells (64), which is in concordance with most published works to date (31, 55, 64). Furthermore, MSCs can also inhibit B-cell differentiation and constitutive expression of chemokine receptors via the release of soluble factors and cell-cell contact mediated possibly by the Programmed Cell Death 1 (PD-1) and its ligand (31, 64). The addition of MSCs, at the beginning of a mixed lymphocyte reaction (MLC), considerably inhibited immunoglobulin production in standard MLC, irrespective of the MSC dose employed, which suggests that third-party MSC are able to suppress allo-specific antibody production, consequently, overcoming a positive cross-match in sensitized transplant recipients (65). However, other in vitro studies have shown that MSCs could support the survival, proliferation and differentiation to antibody-secreting cells of B-cells from normal individuals and from pediatric patients with systemic lupus erythematosus (66, 67). A major mechanism of B-cell suppression was hMSC production of soluble factors, as indicated by transwell experiments, where hMSCs inhibited B-cell differentiation shown as significant impairment of IgM, IgG, and IgA production. CXCR4, CXCR5, and CCR7 B-cell expression, as well as chemotaxis to CXCL12, the CXCR4 ligand, and CXCL13, the CXCR5 ligand, were significantly down-regulated by hMSCs, suggesting that these cells affect chemotactic properties of B-cells (Fig 1). B-cell costimulatory molecule expression and cytokine production were unaffected by hMSCs (64). Regardless of the controversial in vitro effects, B-cell response is mainly a T-cell dependent mechanism, and thus its outcome is significantly influenced by the MSC-mediated inhibition of T-cell functions. More recently, Corcione et al have shown that systemic administration of MSCs to mice affected by experimental autoimmune encephalomyelitis (EAE), a prototypical disease mediated by self-reactive T cells, results in striking disease amelioration mediated by the induction of peripheral tolerance (52). In addition, it has been shown that tolerance induction by MSCs may occur also through the inhibition of dendritic-cell maturation and function (34, 35), thus suggesting that activated T cells are not the only targets of MSCs.

Low concentrations of IFN- upregulate the expression of MHC-II molecules by MSCs, which indicates that they could act as antigen presenting cells (APCs) early in an immune response, when the level of IFN- are low (68, 69). However, this process of MHC-II expression by MSCs, along with the potential APC characteristics, was reversed as IFN- concentrations increased. These observations could suggest that MSCs function as conditional APC in the early phase of an immune response, while later switch into an immunosuppressive function (68). Since bone marrow might be a site for the induction of T-cell responses to blood-borne antigens (70), and since MSC are derived from the stromal progenitor cells that reside in the bone marrow, therefore, MSC express a yet unidentified role in the control of the immune response physiology of the bone marrow. Dendritic cells are the main APC for T-cell responses, and MSC-mediated suppression of DC maturation would prohibit efficient antigen presentation and thus, the clonal expansion of T-cells. Direct interactions of MSCs with T-cells in vivo could lead to the arrest of T-cell proliferation, inhibition of CTL-mediated cytotoxicity and generation of CD4+ regulatory T-cells. As a consequence, impaired CD4+ T-cell activation would translate into defective T-cell help for B-cell proliferation and differentiation to antibody-secreting cells.

The hMSCs express few to none of the B7-1/B7-2 (CD80/CD86) costimulatorytype molecules; this appears to contribute, at least in part, to their immune privilege characteristic. Mechanisms that lead to immune tolerance rely on interrelated pathways that involve complex cross talk and cross regulation of T-cells and APCs by one another. Both soluble mediators and modulation exerted via complex networks of cytokines and costimulatory molecules appear to play a role in MSC regulation of T cells, and these mechanisms invoke both contact-dependent and -independent pathways.

Although many of the studies use MSC-conditioned medium, both contact-dependent and -independent mechanisms are probably invoked in the therapeutic use of MSCs (20, 71). In addition to cytokines, the network of costimulatory molecules is hypothesized to play a prominent role in modulating tolerance and inflammation. MSCs down-regulate the expression of costimulatory molecules (30, 72, 73). The discovery of new functions for B7 family members, together with the identification of additional B7 and CD28 family members, is revealing new ways in which the B7:CD28 family may regulate T-cell activation and tolerance. Not only do CD80/86:CD28 interactions promote initial T-cell activation, they also regulate self-tolerance by supporting CD4+CD25+ Treg homeostasis (74-76). Cytotoxic T-lymphocyte antigen 4 (CTLA-4) can exert inhibitory effects in both B7-1/B7-2dependent and independent fashions. B7-1 and B7-2 can signal bi-directionally through engaging CD28 and CTLA-4 on T cells and by delivering signals into B7-expressing cells (77). The B7 family membersinducible co-stimulator (ICOS) ligand, PD-L1 (B7-H1), PD-L2 (B7-DC), B7-H3, and B7-H4 (B7x/B7-S1)are expressed on professional APC cells, while B7-H4 and B7-H1 are expressed on hMSCs and on cells within non-lymphoid organs. These observations may provide a new means for regulating T-cell activation and tolerance in peripheral tissues (31, 71, 78). ICOS and PD-1 are expressed upon T-cell-induction, and they regulate previously activated T-cells (79). Both the ICOS:ICOSL pathway and the PD-1:PD-L1/PD-L2 pathway play a critical role in regulating T-cell activation and tolerance (79). There is consensus that both CTLA-4 and PD-1 inhibit T-cell and B-cell activation and may play a crucial role in peripheral tolerance (79, 80). Both CTLA-4 and PD-1 functions are associated with Rheumatoid Arthritis (RA) and other autoimmune diseases. PD-1 is over expressed on CD4+ T cells in the synovial fluid of RA patients (81). Whether or not these costimulatory molecules are critical mediators of MSC-mediated immune suppression and/or tolerance in vivo is still under current investigation.

Studies have shown that MSCs escape the immune system, and this makes them a potential therapeutic tool for various transplantation procedures. MSCs express intermediate levels of HLA major histocompatibility complex (MHC) class I molecules (16, 50, 82, 83), while they do not express HLA class II antigens of the cell surface. However, HLA class II is readily detectable by Western blot on whole-cell lysates of unstimulated adult MSCs, thus suggesting that MSCs contain intracellular deposits of HLA class II allo-antigens (83). Cell-surface expression can be induced by treatment of the cells with IFN- for 1 or 2 days. Unlike adult MSCs, the fetal liver derived cells have no intracellular nor cell surface HLA class II expression (84), but incubation with IFN- initiated their intracellular expression followed by surface expression. Differentiation of MSCs into their mesodermal lineages of bone, cartilage, or adipose tissue, both in adult and fetal MSCs continued to express HLA-I, but not class II (84). Undifferentiated MSCs in vitro fail to elicit a proliferative response from allogeneic lymphocytes, thus suggesting that the cells are not inherently immunogenic (28, 30, 50). When pre-cultured with IFN- for full HLA class II expression, MSCs still escape recognition by allo-reactive T-cells, (83, 84) as is the case with MSCs differentiated adipocytes, osteoblasts, and chondrocytes. Limited in vivo data demonstrate the persistence of allogeneic MSCs into immunocompetent hosts after transplantation. In one patient treated with MSCs, DNA of donor MSC could not be detected in any organ at autopsy few weeks after the infusion, while in another patient receiving MSCs from two donors, the donor DNA from both donors was detected in lymph node and colon, the target organs of GVHD, within weeks after infusion (85). Data from our lab indicated that MSC were undetectable after two weeks in an allogeneic system (86). Therefore, the question of whether MSCs are recognized by an intact allogeneic immune system in vivo remains open, although the in vitro data support the theory that MSCs escape the immune system. MSCs do not express FAS ligand or costimulatory molecules, such as B7-1, B7-2, CD40, or CD40L (50). When costimulation is inadequate, T-cell proliferation can be induced by the addition of exogenous costimulation. However, MSCs differ from other cell types, and no T-cell proliferation can be observed when they are cultured with HLA-mismatched lymphocytes in the presence of a CD28-stimulating antibody (50). However, in agreement with the in vitro data, infusion or implantation of allogeneic and MHC-mismatched MSCs into baboons has been well tolerated (87-89). Unique immunologic properties of MSCs were also suggested by the fact that engraftment of human MSCs occurred after intra-uterine transplantation into sheep, even when the transplantation was performed after the fetuses became immunocompetent (90). MSC mainly fail to activate T-cells and show to be targets for CD8+ T cell-cytotoxicity, althought controversial (60). Phyto-hemagglutinin (PHA) blasts, generated to react against a specific donor, will lyse chromium-labeled mononuclear cells from that individual but it will not lyse MSCs derived from the same donor. Furthermore, killer cell inhibitory receptor (KIR ligand)mismatched natural killer cells do not lyse MSCs (60). Thus, MSCs, although incompatible at the MHC, tend to escape the immune system.

Although MSCs are transplantable across allogeneic barriers, a delayed type hypersensitivity reaction can lead to rejection in xenogenic models of human MSCs injected into immunocompetent rats (91). In this study, MSCs were identified in the heart muscle of severe compromised immune deficiency rats, in contrast to that of immunocompetent rats. In the latter group, peripheral blood lymphocytes proliferated after re-stimulation with human MSCs in vitro, thus suggesting cellular immunization. Such a proliferative response in vitro has not been detected in humans treated with intravenous (IV) infusion of allogeneic MSCs (Le Blanc and Ringdn, unpublished data, 2004).

Several studies have acknowledged the immunosuppressive activities of MSCs, but the underlying mechanisms are far from being fully characterized. The initial step in the interaction between MSCs and their target cells involves cellcell contact mediated by adhesion molecules, in concordance with studies showing the dependence of T-cell proliferation on the engagement of PD-1 by its ligand (31). Several soluble immunosuppressive factors, either produced constitutively by MSCs or released following cross-talk with target cells have been reported, including nitric oxide and indoleamine 2,3-dioxygenase (IDO), which are only released by MSC after IFN- stimulation with target cells (92, 93), and thus not in a constitutive manner. IDO induces the depletion of tryptophan from the local environment, which is an essential amino acid for lymphocyte proliferation. MSC-derived IDO was reported as a requirement to inhibit the proliferation of IFN--producing TH1 cells (92) and together with prostaglandin E2 (PGE-2) to block NK-cell activity (Fig 1) (44). In addition, IFN-, alone or in combination with TNF-, IL-1 or IL-1, stimulates the production of chemokines by mouse MSCs that attract T-cells and stimulate the production of inducible nitric-oxide synthase (iNOS), which in turn inhibits T-cell activation through the production of nitric oxide (56). It is worth noting that MSCs from IFN- receptor (IFN--R1) deficient mice do not have immunosuppressive activity, which highlights the vital role of IFN- in the immunosuppressive function of MSC (56).

Additional soluble factors, such as transforming growth factor-1 (TGF-1), hepatocyte growth factor (HGF), IL-10, PGE-2, haem-oxygenase-1 (HO1), IL-6 and soluble HLA-G5, are constitutively produced by MSCs (28, 34, 51, 63, 94) or secreted in response to cytokines released by target cells upon interacting with MSC. TNF- and IFN- have been shown to stimulate the production of PGE-2 by MSCs above constitutive level (34). Furthermore, IL-6 was shown to dampen the respiratory burst and to delay the apoptosis of human neutrophils by inducing phosphorylation of the transcription factor signal transducer and activator of transcription 3 (47), and to inhibit the differentiation of bone-marrow progenitor cells into DCs (95).

The failure to reverse suppression, when neutralizing antibodies against IL-10, TGF- and IGF were added to MLR reactions does point to the possibility that MSC may secrete as yet uncharacterized immunosuppressive factors (93). Galectin-1 and Galectin-3, newly characterized lectins, are constitutively expressed and secreted by human bone marrow MSC. Inhibition of galectin-1 and galectin-3 gene expression with small interfering RNAs abrogated the suppressive effect of MSC on allogeneic T-cells (Fig 1) (96). The restoration of T-cell proliferation in the presence of - lactose indicates that the carbohydrate-recognition domain of galectins is responsible for the immunosuppression of T-cells and highlights an extracellular mechanism of action for the MSC-secreted galectins. In this respect, the inhibition of T-cell proliferation could result from either direct effects of galectin-1 and galectin-3 on T cells and/or through a direct or an indirect on effect on dendritic cells (97).

HLA-G5 represents another important molecule involved in MSC mediated regulation of the immune response, where its production has been shown to suppress T-cell proliferation, as well as NK-cell and T-cell cytotoxicity, while promoting the generation of Tregs (63, 98). HLA-G protein expression is constitutive and the level is not modified upon stimulation by allogeneic lymphocytes in MSC/MLR. HLA-G5 is detected on MSCs by real-time reverse-phase polymerase chain reaction, immune-fluorescence, flow cytometry and enzyme-linked immunosorbent assay in the supernatant (99). Cell contact between MSCs and activated T-cells induces IL-10 production, which, in turn, stimulates the release of soluble HLA-G5 by MSCs (63). It is worth nothing that none of these molecules have an exclusive role and that MSC-mediated immune-regulation is a redundant system that is mediated by several molecules.

One important characteristic of hMSCs is their ability to suppress inflammation resulting from injury, as well as, resulting from allogeneic solid organ transplants, and autoimmune disease. Consistent with in vitro studies, murine allogeneic MSCs are effective cellular therapy models in the treatment of murine models of human disease (52, 100-102). Several studies have documented the substantial clinical improvements observed in animal models, when MSC were systemically introduced as a therapy in mouse models of multiple sclerosis (102, 103), inflammatory bowel disease (104-106), infarct, stroke, and other neurologic diseases (107, 108), as well as diabetes (109). These findings strongly suggest that xenogeneic hMSCs are not immunologically recognized by various immunocompetent mouse models of disease and are able to home to sites of inflammation. However, the mechanisms behind the immunosuppressive actions at the site of inflammation and its association with the homing activity have not yet been completely elucidated.

Nitric Oxide (NO) mediate its effect partly through phosphorylation of Stat-5, which results in suppression of T- cell proliferation, partly through the inhibition of NO synthase or the inhibition of prostaglandin synthesis. This reveals the MSC-dependent effects on proliferation. Although indoleamine-2, 3-dioxygenase (IDO) has been hypothesized to be critical in mediating the effect of NO, neutralizing IDO by using a blocking antibody did not interfere with NOs suppressive effects (93, 110).

Within an in vivo setting, injury, inflammation, and/or foreign cells can lead to T-cell activation, which results in those T-cells producing proinflammatory cytokines including, but not limited to, TNF-, IFN-, IL-1, and IL-1. Combinations of cytokines may also induce cell production of chemokines, some of which bind to CXCR3-R expressing cells (including T cells) that co-localize with MSCs. MSCs then produce NO, which inhibits Stat-5 phosphorylation, thereby leading to cell-cycle arrest (and thus halting T cell proliferation) (Fig 1) (110). In addition, iNOS appears to be important in mouse MSC in vivo effects. MSCs from mice that lack iNOS (or IFN-R1) are unable to suppress GVHD. In contrast to mouse MSCs that use NO in mediating their immune-suppressive effect, hMSCs and MSCs from non-human primates appear to mediate their immune-suppressive effects via IDO (56). There is some controversy about whether the effect of IDO results from local depletion of tryptophan, or from the accumulation of tryptophan metabolites (which is suggested by data showing that use of a tryptophan antagonist, 1-methyl-L tryptophan, restored allo-reactivity that would otherwise have been suppressed by MSCs). In addition to its effect on the JAK-STAT pathway, NO may also influence mitogen activated protein kinase and nuclear factor B, which would cause a reduction in the gene expression of proinflammatory cytokines.

The clinical experience with and the safety of MSCs is of utmost interest for their wide therapeutic applications. The pioneering in vivo studies with MSC focused on the engraftment facilitation for the haematopoietic stem cells (111). Further work also focused on the regenerative functions of MSC in terms of functional repair of damaged tissues (112). Hypoimmunogenicity of MSC provided a critical advantage in their use for clinical and therapeutic purposes in vitro (50), followed by pre-clinical studies (29) and reaching the human clinical studies (32) with the use of allogeneic donors. Allogeneic MSC have proved to be an option with major advantages in clinical use, since the use of autologous MSC is hindered by the limited time frame for clonal expansion and the costly in vitro proliferation. However, some sub-acute conditions, such as autoimmune diseases, might allow the use of autologous MSCs and their culture in vitro. It is worth noting that some reports have recently challenged the belief that allogeneic MSCs are poorly immunogenic (113, 114), indicating that in some cases an autologous MSC source could be advantageous. Recent reports have shown that MSCs from patients with autoimmune disease have a normal capability to support hematopoiesis, (115) and to exercise immunomodulatory functions (116), and to show a normal phenotypic characteristics (117).

The perspective role of adult stem cells in degenerative disease conditions, where there is progressive tissue damage and an inability to repair, possibly due to the depletion of stem cell populations or functional alteration, has been considered. In cases of osteoarthritis, a disease of the joints where there is progressive and irreversible loss of cartilage characterized by changes in the underlying bone, Murphy et al showed that the proliferative capacity of the MSC was substantially reduced, and this was independent of the harvest site from patients with end-stage OA undergoing joint replacement surgery (118). In this study the marrow samples were harvested both from the site of surgery (either the hip or the knee) and also from the iliac crest. These effects were apparently disease-related, and not age-related. However, the data suggest that susceptibility to OA and perhaps other degenerative diseases may be due to the reduced mobilization or proliferation of stem cells. In addition, successfully recruited cells may have a limited capacity to differentiate, leading to defective tissue repair. Alternatively, the altered stem cell activity may be in response to the elevated levels of inflammatory cytokines seen in OA, which was confirmed by several other investigators (119, 120).

Similarly, the functional impairment of the anti-proliferative effect of MSCs derived from patients with aplastic anaemia (121) or multiple myeloma (122) might be resulting from an intrinsic abnormality in the microenvironment of the bone marrow, which is consistent with the possible use of autologous MSC for therapeutic purposes.

With the knowledge of the homing capacity of MSC and their capacity to engraft into the recipients bone after systemic administration, MSCs have been utilized to treat children with severe osteogenesis imperfecta, leading to improved parameters of increased growth velocity and total body mineral content associated with fewer fractures (123). Systemic infusion of allogeneic MSCs also led to encouraging bone marrow recovery in patients with tumors following chemotherapy (123). The immunosuppressive effect of infused MSCs has been successfully shown in acute, severe graft-versus-host disease (GvHD) (32). The probable effect of MSC was the inhibition of donor T-cell reactivity to histocompatibility antigens of the recipient tissue. Currently, there is no successful therapy for steroid-refractory acute GVHD. The possible role of MSCs in this context is therefore of potential interest. Le Blanc et al reported a case of grade IV acute GVHD of the gut and liver in a patient who had undergone ASCT with cells from an unrelated female donor (32). The patient was unresponsive to all types of immunosuppression drugs. When the patient was infused with 2x 106 MSCs per kilogram from his HLA-haploidentical mother, his GVHD responded with a decline in bilirubin and normalization of stools. After the MSC infusion, DNA analysis of his bone marrow showed the presence of minimal residual disease (124). When immunosuppression was discontinued, the patient again developed severe acute GVHD, with its associated symptoms within a few weeks.

Modulation of host allo-reactivity led to accelerated bone-marrow recovery in patients co-transplanted with MSCs and haplo-identical HSCs (125). Clinical trials are being conducted on the immunomodulatory potential of MSCs in the treatment of Crohns disease, with the potential for those cells to contribute to the regeneration of gastrointestinal epithelial cells (126).

As described previously, MSCs are characterized by their hypoimmunogenicity. In 2000, data from several research groups demonstrated long-term allo-MSC engraftment in a variety of non-cardiac tissues in the absence of immunosuppression (88, 90). On the basis of these observations, investigators began to look into the possibility of allo-MSCs engraftment into affected myocardium in rats, and later in swine, where allo-MSCs were found to readily engraft in necrotic myocardium and favorably alter ventricular function (2). The allo-MSC engraftment occurred without evidence of immunologic rejection or lymphocytic infiltration in the absence of assisted immunosuppressive therapy emphasizing some of the apparent advantages of these cells over other cell populations for cellular cardiomyoplasty. The immunologically privileged status of MSCs was also observed in xenogeneic setting, where Saito et al injected MSC intravenously from C57BL/6 mice into immunocompetent adult Lewis rats (127). When these animals were later subjected to MIs, murine MSCs could be identified in the region of necrosis, and these cells expressed muscle specific proteins not present before coronary ligation.

Consistent with results from in vitro studies, murine allogeneic MSCs are effective in the treatment of murine models of human disease (52, 103, 128). Several studies have reported clinical improvements in mouse models of multiple sclerosis and amyotrophic lateral sclerosis, inflammatory bowel disease, stroke, diabetes, infarct and GVHD using I.V. injected xenogeneic hMSCs rather than allogeneic MSCs (108, 109). A major advantage in using hMSCs in mouse models of human disease is that the possibility of gathering mechanistic data through measuring biomarkers from body fluids or using noninvasive imaging technology, which may prove to be an advantage in clinical studies when applied on humans.

In experiments designed to study the trafficking of hMSCs, investigators used mouse models of severe erosive polyarthritis characterized by an altered transgene allele that results in chronic over-expression of TNF- and which resemble human RA patients (60, 72). The motive behind utilizing these mice models was to investigate similarities in MSC homing with mouse models of chronic asthma and acute lung injury. Injected hMSC revealed a reduction in ankle arthritis parameters associated with decrease appendage related erythema, possibly due to the MSC localization to ankle joints as revealed by bioluminescence (129). Similar observations for inducing tolerance were made using adipose-derived MSC, where Treg were induced in RA PBMC and in mouse models of arthritis (36, 130). Furthermore, studies of rheumatoid arthritis T-cells showed a down-regulation of effector response using adipose-derived MSCs (131). Variations in this potential described by the capability of MSCs to down-regulate collagen-induced arthritis, and in the ability to induce Tregs, depend on the source of MSC (mouse vs. human) and its characteristics (primary isolate of MSC line), which reflect on difference in function compared to primary expanded MSC (132). Other studies reported that in the collagen-induced model of arthritis, mice infused with MSCs have increased numbers of CD4+CD25+ cells that express FoxP3 and thus reveal a Treg phenotype (20). Recent data on collagen-induced arthritis model, where murine MSCs did not reveal therapeutic benefits against arthritis in vivo, but did show anti-proliferative effect in vitro suggest that there is no appropriate in vitro measures that can be accurately extrapolated into a potential therapeutic utility of MSCs in vivo, and that mouse MSCs show difference in functional characteristics to hMSC in terms of immunoregulatory capacity (133).

MSCs immunological properties appeared to have potential therapeutic advantages in other forms of autoimmune diseases, especially in type 1 diabetes. In NOD mouse model, several physiological defects that aim to maintain peripheral and central tolerance contribute to the development of autoimmune diabetes. These defects are summed up as a combination of immune cell dysfunction (including T-cell, NK cells, B-cells, and dendritic cells), associated with the presence of inflammatory cytokine milieu (134). MSCs possess specific immunomodulatory properties capable of halting autoimmunity through immunomodulation processes described in this chapter. The processes might be through a direct effect via the presentation of differential levels of negative costimulatory molecules and the secretion of regulatory cytokines that affect regulatory T-cells/autoreactive T-cells. Furthermore, MSCs could modulate the immunological dysregulation observed in antibody producing B-cells and cytotoxic NK cells. Dendritic cells have been shown to be defective in NOD mice characterized by higher levels of costimulation with a potential capability to shift to a TH-1 type of immune response.

In an experimental mouse model of diabetes induced by streptozotocin, it was observed that MSCs promoted the endogenous repair of pancreatic islets and renal glomeruli (109). Similarly, co-infusion of MSCs and bone-marrow cells inhibited the proliferation of -cell-specific T-cells isolated from the pancreas of diabetic mice and restored insulin and glucose levels through the induction of recipient-derived pancreatic -cell regeneration in the absence of trans-differentiation of MSCs (135). These studies show that the in vivo administration of MSCs is clinically efficacious through the modulation of pathogenic - and T-cell responses and through potent bystander effects on the target tissue.

The timing of MSC infusion seems to be a critical parameter in their therapeutic efficacy. In the EAE mouse model of multiple sclerosis, MSC systematically injected at disease onset ameliorated myelin oligodendrocyte glycoprotein (MOG)-induced EAE and further decreased the infiltration T-cells, B-cells and macrophages into the central nervous system (CNS). Furthermore, T cells isolated from the lymph nodes of MSC-treated mice did not proliferate after in vitro re-challenge with MOG peptide, which is an indication of the induction of T-cell anergy (52). Systematic injection of MSCs was found to inhibit the in vivo production of pathogenic plp-specific antibodies and to suppress the encephalitogenic potential of plp-specific T cells in passive-transfer experiments. In this model, the MSCs migrated to the lymphoid organs, as well as, to the inflamed CNS, where they exercised a protective effect on the neuronal axons in situ (135, 136). In these studies, the therapeutic effect of MSCs depended on the release of anti-apoptotic, anti-inflammatory and trophic molecules, as occurred in the case of stroke in rats (137), and, possibly, on the recruitment of local progenitors and their subsequent induction to differentiate into neural cells (138). As trophic effect, the MSCs appeared to favor oligo-dendrogenisis by neural precursor cells (139).

Several other studies have provided insights into the effects of MSCs mediated by cytokines. In a model of acute renal failure, the administration of MSCs increased the recovery of renal function through the inhibition of production of proinflammatory cytokines, such as Il-1, TNF and IFN, and through an anti-apoptotic effect on target cells (140). Along the same line, the anti-inflammatory activity of MSCs was revealed in a mouse model of lung fibrosis, where they inhibited the effects of IL-1-producing T cells and TNF-producing macrophages through the release of IL-1 receptor antagonist (IL-1RA) (141). The release of trophic factors such as the WNT-associated molecule secreted frizzled-related protein 2 (SFRp2), which leads to the rescue of ischemic cardiomyocytes and the restoration of ventricular functions represent another important function for MSC (142).

With all the promising therapeutic potential of MSC, there seems to be a growing concern about their association with tumors. The immunoregulatory and anti-proliferative effects of MSCs led to several studies investigating the inhibitory effect of MSCs on tumor growth. Inhibition or, more frequently, stimulation of tumor-cell proliferation in vitro and/or tumor growth in vivo by MSCs has been reported (143-145). The heterogeneous nature of the MSC populations and the different experimental tumor models used, contribute to the effect of tumors on MSC in which the microenvironment generated by tumors influence the behavior of MSCs (146). Two main mechanisms are probably involved in the enhancement of tumor growth by MSCs. First, the cell-to-cell cross-talk between MSCs and tumor cells contribute to tumor progression, thus integrating within the tumor stroma (147), and second, the suppressive effects of MSCs on the immune system of tumor-bearing hosts might facilitate tumorigenesis, as shown for the inhibition of melanoma rejection, possibly mediated by regulatory CD8+ T cells (144). Irrespective of the possible interactions between cancer cells, immune cells and MSCs, the potential risk of stimulating the growth cancer by MSCs must be considered.

As a whole, the data accumulated from preclinical and clinical data indicate that bone marrow-derived MSCs have, in addition to their therapeutic purposes in regenerative medicine, effects that can result from other characteristics, such as their anti-proliferative and anti-inflammatory properties. The immuno suppressive activity of MSCs provides means for inducing peripheral tolerance following systemic injection mediated through the inhibition of cell division, thereby preventing their responsiveness to antigenic triggers while maintaining them in a quiescent state. In addition, the clinical efficacy of MSCs in different experimental model seems to occur almost only during the acute phase of disease associated with limited trans-differentiation, which indicates that the therapeutic effectiveness of MSCs relies heavily on their ability to modify microenvironments. These modifications occur through the release of anti-inflammatory cytokines, and anti-apoptotic and trophic molecules that promote the repair and protection of damaged tissues, as well as, maintain the integrity of the immune cells.

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Mesenchymal Stem Cells: Immunology and Therapeutic ...

Induced pluripotent stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from adult cells. The iPSC technology was pioneered by Shinya Yamanakas lab in Kyoto, Japan, who showed in 2006 that the introduction of four specific genes encoding transcription factors could convert adult cells into pluripotent stem cells.[1] He was awarded the 2012 Nobel Prize along with Sir John Gurdon "for the discovery that mature cells can be reprogrammed to become pluripotent." [2]

Pluripotent stem cells hold great promise in the field of regenerative medicine. Because they can propagate indefinitely, as well as give rise to every other cell type in the body (such as neurons, heart, pancreatic, and liver cells), they represent a single source of cells that could be used to replace those lost to damage or disease.

The most well-known type of pluripotent stem cell is the embryonic stem cell. However, since the generation of embryonic stem cells involves destruction (or at least manipulation) [3] of the pre-implantation stage embryo, there has been much controversy surrounding their use. Further, because embryonic stem cells can only be derived from embryos, it has so far not been feasible to create patient-matched embryonic stem cell lines.

Since iPSCs can be derived directly from adult tissues, they not only bypass the need for embryos, but can be made in a patient-matched manner, which means that each individual could have their own pluripotent stem cell line. These unlimited supplies of autologous cells could be used to generate transplants without the risk of immune rejection. While the iPSC technology has not yet advanced to a stage where therapeutic transplants have been deemed safe, iPSCs are readily being used in personalized drug discovery efforts and understanding the patient-specific basis of disease.[citation needed]

Depending on the methods used, reprogramming of adult cells to obtain iPSCs may pose significant risks that could limit their use in humans. For example, if viruses are used to genomically alter the cells, the expression of oncogenes (cancer-causing genes) may potentially be triggered. In February 2008, scientists announced the discovery of a technique that could remove oncogenes after the induction of pluripotency, thereby increasing the potential use of iPS cells in human diseases.[4] In April 2009, it was demonstrated that generation of iPS cells is possible without any genetic alteration of the adult cell: a repeated treatment of the cells with certain proteins channeled into the cells via poly-arginine anchors was sufficient to induce pluripotency.[5] The acronym given for those iPSCs is piPSCs (protein-induced pluripotent stem cells).

iPSCs are typically derived by introducing a specific set of pluripotency-associated genes, or reprogramming factors, into a given cell type. The original set of reprogramming factors (also dubbed Yamanaka factors) are the genes Oct4 (Pou5f1), Sox2, cMyc, and Klf4. While this combination is most conventional in producing iPSCs, each of the factors can be functionally replaced by related transcription factors, miRNAs, small molecules, or even non-related genes such as lineage specifiers.

iPSC derivation is typically a slow and inefficient process, taking 12 weeks for mouse cells and 34 weeks for human cells, with efficiencies around 0.01%0.1%. However, considerable advances have been made in improving the efficiency and the time it takes to obtain iPSCs. Upon introduction of reprogramming factors, cells begin to form colonies that resemble pluripotent stem cells, which can be isolated based on their morphology, conditions that select for their growth, or through expression of surface markers or reporter genes.

Induced pluripotent stem cells were first generated by Shinya Yamanaka's team at Kyoto University, Japan, in 2006.[1] Their hypothesis was that genes important to embryonic stem cell function might be able to induce an embryonic state in adult cells. They began by choosing twenty-four genes that were previously identified as important in embryonic stem cells, and used retroviruses to deliver these genes to fibroblasts from mice. The mouse fibroblasts were engineered so that any cells that reactivated the ESC-specific gene, Fbx15, could be isolated using antibiotic selection.

Upon delivery of all twenty-four factors, colonies emerged that had reactivated the Fbx15 reporter, resembled ESCs, and could propagate indefinitely. They then narrowed their candidates by removing one factor at a time from the pool of twenty-four. By this process, they identified four factors, Oct4, Sox2, cMyc, and Klf4, which as a group were both necessary and sufficient to obtain ESC-like colonies under selection for reactivation of Fbx15.

Similar to ESCs, these first-generation iPSCs showed unlimited self-renewal and demonstrated pluripotency by contributing to lineages from all three germ layers in the context of embryoid bodies, teratomas, fetal chimeras. However, the molecular makeup of these cells, including gene expression and epigenetic marks, was somewhere between that of a fibroblast and an ESC, and the cells also failed to produce viable chimeras when injected into developing embryos.

In June 2007, the same group published a breakthrough study along with two other independent research groups from Harvard, MIT, and the University of California, Los Angeles, showing successful reprogramming of mouse fibroblasts into iPS cells. Unlike the first generation of iPS cells, these cells could produce viable chimeric mice and could contribute to the germline, the 'gold standard' for pluripotent stem cells. These cells were derived from mouse fibroblasts by retroviral-mediated expression of the same four transcription factors (Oct4, Sox2, cMyc, Klf4), but the researchers used a different marker to select for pluripotent cells. Instead of Fbx15, they used Nanog, a gene that is functionally important in ESCs. By using this different strategy, the researchers were able to create iPS cells that were more similar to ESCs than the first generation of iPS cells, and independently proved that it was possible to create iPS cells that are functionally identical to ESCs.[6][7][8][9]

Unfortunately, two of the four genes used (namely, c-Myc and KLF4) are oncogenic, and 20% of the chimeric mice developed cancer. In a later study, Yamanaka reported that one can create iPSCs even without c-Myc. The process takes longer and is not as efficient, but the resulting chimeras didn't develop cancer.[10]

Induced pluripotent cells have been made from adult stomach, liver, skin cells, blood cells, prostate cells and urinary tract cells.[11]

In November 2007, a milestone was achieved[12][13] by creating iPSCs from adult human cells; two independent research teams' studies were released one in Science by James Thomson at University of WisconsinMadison[14] and another in Cell by Shinya Yamanaka and colleagues at Kyoto University, Japan.[15] With the same principle used earlier in mouse models, Yamanaka had successfully transformed human fibroblasts into pluripotent stem cells using the same four pivotal genes: Oct3/4, Sox2, Klf4, and c-Myc with a retroviral system. Thomson and colleagues used OCT4, SOX2, NANOG, and a different gene LIN28 using a lentiviral system.

On 8 November 2012, researchers from Austria, Hong Kong and China presented a protocol for generating human iPSCs from exfoliated renal epithelial cells present in urine on Nature Protocols.[16] This method of acquiring donor cells is comparatively less invasive and simple. The team reported the induction procedure to take less time, around 2 weeks for the urinary cell culture and 3 to 4 weeks for the reprogramming; and higher yield, up to 4% using retroviral delivery of exogenous factors. Urinary iPSCs (UiPSCs) were found to show good differentiation potential, and thus represent an alternative choice for producing pluripotent cells from normal individuals or patients with genetic diseases, including those affecting the kidney.[16]

Although the methods pioneered by Yamanaka and others have demonstrated that adult cells can be reprogrammed to iPS cells, there are still challenges associated with this technology:

The table at right summarizes the key strategies and techniques used to develop iPS cells over the past half-decade. Rows of similar colors represents studies that used similar strategies for reprogramming.

One of the main strategies for avoiding problems (1) and (2) has been to use small compounds that can mimic the effects of transcription factors. These molecule compounds can compensate for a reprogramming factor that does not effectively target the genome or fails at reprogramming for another reason; thus they raise reprogramming efficiency. They also avoid the problem of genomic integration, which in some cases contributes to tumor genesis. Key studies using such strategy were conducted in 2008. Melton et al. studied the effects of histone deacetylase (HDAC) inhibitor valproic acid. They found that it increased reprogramming efficiency 100-fold (compared to Yamanakas traditional transcription factor method).[25] The researchers proposed that this compound was mimicking the signaling that is usually caused by the transcription factor c-Myc. A similar type of compensation mechanism was proposed to mimic the effects of Sox2. In 2008, Ding et al. used the inhibition of histone methyl transferase (HMT) with BIX-01294 in combination with the activation of calcium channels in the plasma membrane in order to increase reprogramming efficiency.[26] Deng et al. of Beijing University reported on July 2013 that induced pluripotent stem cells can be created without any genetic modification. They used a cocktail of seven small-molecule compounds including DZNep to induce the mouse somatic cells into stem cells which they called CiPS cells with the efficiency at 0.2% comparable to those using standard iPSC production techniques. The CiPS cells were introduced into developing mouse embryos and were found to contribute to all major cells types, proving its pluripotency.[27][28]

Ding et al. demonstrated an alternative to transcription factor reprogramming through the use of drug-like chemicals. By studying the MET (mesenchymal-epithelial transition) process in which fibroblasts are pushed to a stem-cell like state, Dings group identified two chemicals ALK5 inhibitor SB431412 and MEK (mitogen-activated protein kinase) inhibitor PD0325901 which was found to increase the efficiency of the classical genetic method by 100 fold. Adding a third compound known to be involved in the cell survival pathway, Thiazovivin further increases the efficiency by 200 fold. Using the combination of these three compounds also decreased the reprogramming process of the human fibroblasts from four weeks to two weeks. [29][30]

Another key strategy for avoiding problems such as tumor genesis and low throughput has been to use alternate forms of vectors: adenovirus, plasmids, and naked DNA and/or protein compounds.

In 2008, Hochedlinger et al. used an adenovirus to transport the requisite four transcription factors into the DNA of skin and liver cells of mice, resulting in cells identical to ESCs. The adenovirus is unique from other vectors like viruses and retroviruses because it does not incorporate any of its own genes into the targeted host and avoids the potential for insertional mutagenesis.[31] In 2009, Freed et al. demonstrated successful reprogramming of human fibroblasts to iPS cells.[32] Another advantage of using adenoviruses is that they only need to present for a brief amount of time in order for effective reprogramming to take place.

Also in 2008, Yamanaka et al. found that they could transfer the four necessary genes with a plasmid.[33] The Yamanaka group successfully reprogrammed mouse cells by transfection with two plasmid constructs carrying the reprogramming factors; the first plasmid expressed c-Myc, while the second expressed the other three factors (Oct4, Klf4, and Sox2). Although the plasmid methods avoid viruses, they still require cancer-promoting genes to accomplish reprogramming. The other main issue with these methods is that they tend to be much less efficient compared to retroviral methods. Furthermore, transfected plasmids have been shown to integrate into the host genome and therefore they still pose the risk of insertional mutagenesis. Because non-retroviral approaches have demonstrated such low efficiency levels, researchers have attempted to effectively rescue the technique with what is known as the piggyBac transposon system. The lifecycle of this system is shown below. Several studies have demonstrated that this system can effectively deliver the key reprogramming factors without leaving any footprint mutations in the host cell genome. As demonstrated in the figure, the piggyBac transposon system involves the re-excision of exogenous genes, which eliminates issues like insertional mutagenesis

In January 2014, two articles were published claiming that a type of pluripotent stem cell can be generated by subjecting the cells to certain types of stress (bacterial toxin, a low pH of 5.7, or physical squeezing); the resulting cells were called STAP cells, for stimulus-triggered acquisition of pluripotency.[34]

In light of difficulties that other labs had replicating the results of the surprising study, in March 2014, one of the co-authors has called for the articles to be retracted.[35] On 4 June 2014, the lead author, Obokata agreed to retract both the papers [36] after she was found to have committed research misconduct as concluded in an investigation by RIKEN on 1 April 2014.[37]

Studies by Blelloch et al. in 2009 demonstrated that expression of ES cell-specific microRNA molecules (such as miR-291, miR-294 and miR-295) enhances the efficiency of induced pluripotency by acting downstream of c-Myc .[38] More recently (in April 2011), Morrisey et al. demonstrated another method using microRNA that improved the efficiency of reprogramming to a rate similar to that demonstrated by Ding. MicroRNAs are short RNA molecules that bind to complementary sequences on messenger RNA and block expression of a gene. Morriseys team worked on microRNAs in lung development, and hypothesized that their microRNAs perhaps blocked expression of repressors of Yamanakas four transcription factors. Possible mechanisms by which microRNAs can induce reprogramming even in the absence of added exogenous transcription factors, and how variations in microRNA expression of iPS cells can predict their differentiation potential discussed by Xichen Bao et al.[39]

[citation needed]

The generation of iPS cells is crucially dependent on the genes used for the induction.

Oct-3/4 and certain members of the Sox gene family (Sox1, Sox2, Sox3, and Sox15) have been identified as crucial transcriptional regulators involved in the induction process whose absence makes induction impossible. Additional genes, however, including certain members of the Klf family (Klf1, Klf2, Klf4, and Klf5), the Myc family (c-myc, L-myc, and N-myc), Nanog, and LIN28, have been identified to increase the induction efficiency.

Induced pluripotent stem cells are similar to natural pluripotent stem cells, such as embryonic stem (ES) cells, in many aspects, such as the expression of certain stem cell genes and proteins, chromatin methylation patterns, doubling time, embryoid body formation, teratoma formation, viable chimera formation, and potency and differentiability, but the full extent of their relation to natural pluripotent stem cells is still being assessed.[42]

Gene expression and genome-wide H3K4me3 and H3K27me3 were found to be extremely similar between ES and iPS cells.[43][citation needed] The generated iPSCs were remarkably similar to naturally isolated pluripotent stem cells (such as mouse and human embryonic stem cells, mESCs and hESCs, respectively) in the following respects, thus confirming the identity, authenticity, and pluripotency of iPSCs to naturally isolated pluripotent stem cells:

Recent achievements and future tasks for safe iPSC-based cell therapy are collected in the review of Okano et al.[55]

The task of producing iPS cells continues to be challenging due to the six problems mentioned above. A key tradeoff to overcome is that between efficiency and genomic integration. Most methods that do not rely on the integration of transgenes are inefficient, while those that do rely on the integration of transgenes face the problems of incomplete reprogramming and tumor genesis, although a vast number of techniques and methods have been attempted. Another large set of strategies is to perform a proteomic characterization of iPS cells. The Wu group at Stanford University has made significant progress with this strategy.[56] Further studies and new strategies should generate optimal solutions to the five main challenges. One approach might attempt to combine the positive attributes of these strategies into an ultimately effective technique for reprogramming cells to iPS cells.

Another approach is the use of iPS cells derived from patients to identify therapeutic drugs able to rescue a phenotype. For instance, iPS cell lines derived from patients affected by ectodermal dysplasia syndrome (EEC), in which the p63 gene is mutated, display abnormal epithelial commitment that could be partially rescued by a small compound[57]

An attractive feature of human iPS cells is the ability to derive them from adult patients to study the cellular basis of human disease. Since iPS cells are self-renewing and pluripotent, they represent a theoretically unlimited source of patient-derived cells which can be turned into any type of cell in the body. This is particularly important because many other types of human cells derived from patients tend to stop growing after a few passages in laboratory culture. iPS cells have been generated for a wide variety of human genetic diseases, including common disorders such as Down syndrome and polycystic kidney disease.[58][59] In many instances, the patient-derived iPS cells exhibit cellular defects not observed in iPS cells from healthy patients, providing insight into the pathophysiology of the disease.[60] An international collaborated project, StemBANCC, was formed in 2012 to build a collection of iPS cell lines for drug screening for a variety of disease. Managed by the University of Oxford, the effort pooled funds and resources from 10 pharmaceutical companies and 23 universities. The goal is to generate a library of 1,500 iPS cell lines which will be used in early drug testing by providing a simulated human disease environment.[61]

A proof-of-concept of using induced pluripotent stem cells (iPSCs) to generate human organ for transplantation was reported by researchers from Japan. Human liver buds (iPSC-LBs) were grown from a mixture of three different kinds of stem cells: hepatocytes (for liver function) coaxed from iPSCs; endothelial stem cells (to form lining of blood vessels) from umbilical cord blood; and mesenchymal stem cells (to form connective tissue). This new approach allows different cell types to self-organize into a complex organ, mimicking the process in fetal development. After growing in vitro for a few days, the liver buds were transplanted into mice where the liver quickly connected with the host blood vessels and continued to grow. Most importantly, it performed regular liver functions including metabolizing drugs and producing liver-specific proteins. Further studies will monitor the longevity of the transplanted organ in the host body (ability to integrate or avoid rejection) and whether it will transform into tumors.[62][63] Using this method, cells from one mouse could be used to test 1,000 drug compounds to treat liver disease, and reduce animal use by up to 50,000.[64]

Embryonic cord-blood cells were induced into pluripotent stem cells using plasmid DNA. Using cell surface endothelial/pericytic markers CD31 and CD146, researchers identified 'vascular progenitor', the high-quality, multipotent vascular stem cells. After the iPS cells were injected directly into the vitreous of the damaged retina of mice, the stem cells engrafted into the retina, grew and repaired the vascular vessels.[65][66]

In a study conducted in China in 2013, Superparamagnetic iron oxide (SPIO) particles were used to label iPSCs-derived NSCs in vitro. Labeled NSCs were implanted into TBI rats and SCI monkeys 1 week after injury, and then imaged using gradient reflection echo (GRE) sequence by 3.0T magnetic resonance imaging (MRI) scanner. MRI analysis was performed at 1, 7, 14, 21, and 30 days, respectively, following cell transplantation. Pronounced hypointense signals were initially detected at the cell injection sites in rats and monkeys and were later found to extend progressively to the lesion regions, demonstrating that iPSCs-derived NSCs could migrate to the lesion area from the primary sites. The therapeutic efficacy of iPSCs-derived NSCs was examined concomitantly through functional recovery tests of the animals. In this study, we tracked iPSCs-derived NSCs migration in the CNS of TBI rats and SCI monkeys in vivo for the first time. Functional recovery tests showed obvious motor function improvement in transplanted animals. These data provide the necessary foundation for future clinical application of iPSCs for CNS injury.[67]

In 2014, type O red blood cells were synthesized at the Scottish National Blood Transfusion Service from iPSC. The cells were induced to become a mesoderm and then blood cells and then red blood cells. The final step was to make them eject their nuclei and mature properly. Type O can be transfused into all patients. Each pint of blood contains about two trillion red blood cells, while some 107 million blood donations are collected globally every year. Human transfusions were not expected to begin until 2016.[68]

The first human clinical trial using autologous iPSCs is approved by the Japan Ministry Health and will be conducted in 2014 in Kobe. iPSCs derived from skin cells from six patients suffering from wet age-related macular degeneration will be reprogrammed to differentiate into retinal pigment epithelial (RPE) cells. The cell sheet will be transplanted into the affected retina where the degenerated RPE tissue has been excised. Safety and vision restoration monitoring is expected to last one to three years.[69][70] The benefits of using autologous iPSCs are that there is theoretically no risk of rejection and it eliminates the need to use embryonic stem cells.[70]

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Induced pluripotent stem cell - Wikipedia, the free ...

There are many types of stem cells that are undergoing research and which are producing knowledge about their potential use in treating MS. Many of these studies involve adult mesenchymal (pronounced messENkimmul) stem cells, which are present in many tissues of the body, including bone marrow and fat (adipose tissue). These cells are being tested for their ability both to treat immune disorders and promote tissue repair. Further study is necessary to determine what kind of cells might prove optimal for treating some or all people with MS.

Stem cell therapy, even in the controlled setting of a clinical trial, carries the possibility for substantial risks. Anyone who is considering enrolling in a clinical trial should evaluate carefully the potential adverse events that will be outlined in the informed consent form that trial participants must sign.

HSCT to Reboot the Immune System: One type of procedure that has been explored for several years in MS is called autologous hematopoietic (blood cell-producing) stem cell transplantation -- or HSCT. This procedure has been used in attempts to reboot the immune system, which is believed to launch attacks on the brain and spinal cord in people with MS.

In HSCT, these stem cells (derived from a persons own bone marrow or blood) are stored, and the rest of the individuals immune cells are depleted by chemotherapy or radiation or both. Then the stored stem cells are reintroduced usually by infusion into the vein. The new stem cells migrate to the bone marrow and over time produce new cells. Eventually they repopulate the body with immune cells. The goal of this currently experimental procedure is that the new immune cells will no longer attack myelin or other brain tissue, providing the person, what is hoped to be, a completely new immune system.

This approach is being investigated in Canada, the United States, Europe and elsewhere. For example:

An international clinical trial of this procedure, being led by Dr. Richard Burt of Northwestern University in Chicago, is now recruiting individuals who have not responded to other disease-modifying therapies. THIS TRIAL IS CURRENTLY RECRUITING PARTICIPANTS at its sites at Northwestern University, Rush University Medical Center, University of Sao Paulo, Uppsala University and Sheffield Teaching Hospitals NHS Foundation Trust. Read more about who may be eligible to participate.Dr. Burt and colleagues recently published a case series exploring outcomes for individuals who underwent the procedure.

A multi-center, 5-year trial called the HALT MS (High-Dose Immunosuppression and Autologous Transplantation for Multiple Sclerosis) Study is expected to be completed in 2015. It is testing HSCT in people with MS who have active disease that was not controlled by disease-modifying medications. The trial is funded by the National Institutes of Health and the Immune Tolerance Network. Interim results were recently reported suggesting that after three years, 78.4% of participants experienced no new disease activity. When this trial has completed its five-year duration, it will be an important addition to research needed to determine whether this approach to stem cell transplantation is safe and effective in people with MS.THIS TRIAL IS ONGOING AND NOT SEEKING ADDITIONAL PARTICIPANTS.

Adult Mesenchymal Stem Cells to Reduce Disease and Augment Repair: Another experimental approach being tested in clinical trials is similar to HSCT, except that the individuals immune cells are not destroyed or replaced. An individuals own mesenchymal stem cells are isolated from the bone marrow or blood stream and multiplied in the lab, and then re-introduced in greater numbers into their body. This approach is being tested in several clinical trials including:

A small, open-label, phase I clinical trial at Cleveland Clinic tested the ability of an individuals own mesenchymal stem cells to both inhibit immune mechanisms and to augment intrinsic tissue repair processes in people with relapsing forms of MS. They were given intravenously (infused into the vein). This study was led by Dr. Jeffrey A. Cohen and supported by the Congressionally Directed Medical Research Programs. The National MS Society provided support for a pilot study related to this trial to compare stem cells from people with MS and controls without MS, looking at how the cells survive and function, to enhance understanding from this stem cell trial. This trial, which was designed to evaluate safety and not designed to determine benefits, was completed and preliminary results were presented in September 2014, suggesting that this approach was safe and warrants a phase 2 trial, which is now in planning stages. THIS PLANNED TRIAL IS NOT YET RECRUITING ADDITIONAL PARTICIPANTS.

A small, open label, phase I stem cell trial has begun at the Tisch MS Research Center of New York using individualsown mesenchymal stem cells to derive more specific stem cells called neural progenitor cells. The cells are expanded in the laboratory and then injected into the space around the spinal cord (intrathecal). The goal is to inhibit immune mechanisms and to augment tissue repair. THIS TRIAL IS ONGOING AND NOT SEEKING ADDITIONAL PARTICIPANTS.

A placebo-controlled, phase II stem cell trial involving people with primary progressive MS, secondary-progressive MS and relapsing-remitting MS is getting underway at Ottawa Hospital and Health Sciences Centre in Winnipeg, Canada. The trial will test benefits and safety of using individuals own bone marrow cells, which are extracted and then given by intravenous infusion immediately or six months after extraction. The goal is to inhibit immune mechanisms and to augment tissue repair. THIS TRIAL IS NOT YET RECRUITING PARTICIPANTS.

A small, open label, phase I trial of stem cells derived from placenta (known as PDA-001 manufactured by Celgene Cellular Therapeutics) was completed in 2014, and results suggested this approach was safe. The study involved 16 people with relapsing-remitting or secondary-progressive MS at sites in the U.S. and Canada. This study was designed to evaluate safety and not designed to show effectiveness. In the published paper, the researchers comment that the next step, a proof-of-concept clinical trial, is planned. THIS PLANNED NEXT TRIAL IS NOT YET RECRUITING PARTICIPANTS.

A placebo-controlled, phase II stem cell trial involving people with secondary-progressive MS and primary progressive MS has begun at Frenchay Hospital in Bristol, United Kingdom, testing the benefits and safety of using individuals own bone marrow cells. The cells are extracted and then given by intravenous infusion immediately or one year after the extraction. The goal is to inhibit immune mechanisms and to augment tissue repair. THIS TRIAL IS RECRUITING PARTICIPANTS AT ONE SITE IN THE UNITED KINGDOM.

Larger, longer-term, controlled studies are needed to determine the safety and effectiveness of using stem cells to treat MS. When the results of these and subsequent clinical trials are available, it should be possible to determine what the optimal cells, delivery methods, safety and actual effectiveness of these current experimental therapies might be for different people with MS.

Read more aboutstem cell clinics.

Other Stem Cell Research: Another line of stem cell research in MS relates to efforts to repair nervous system damage directly with stem cells that may replace the cells that make myelin, the protective cover on nerve wires which is damaged during MS, and nerve cells that have been destroyed. One exciting avenue being explored in early stages is the concept of taking samples of a persons skin cells and turning them into stem cells. These cells are called induced pluripotent stem cells or iPSC. The potential advantage of this approach is that its possible such cells would not be rejected by the persons immune system, and this approach bypasses possible ethical concerns connected with human embryonic stem cells.

This research is still in its infancy as studies proceed to determine whether any types of stem cells can reverse MS damage and restore function. Read more about efforts to repair the nervous system.

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Stem Cells in MS - National Multiple Sclerosis Society

Pax7 stability is regulated by the proteasome during myogenesis. (A): Proteasome inhibition results in myogenin (Myog) and Pax7 coexpression (arrows) in adult mouse primary myoblasts (pMbs). Syndecan-4 (Sdc-4) expression was used as lineage marker. Scale bar=10 m. Right panel: quantification (three separate experiments; [meanSEM]) of percentage of Myog(+)/Pax7(+) cells from the total Sdc-4(+) population; Student's t-test; *, p <0.005. (B): Western blot analysis of Pax7 and myogenin expression in 48 hours cultured pMbs treated as in (A). (C): Pax7 levels are significantly increased upon proteasome inhibition during differentiation commitment in C2C12 myoblasts. Myogenin (Myog): differentiation marker, tubulin (Tub): loading control. Right panel: quantification of Pax7 fold change (meanSEM) of three separate experiments. One-way analysis of variance (ANOVA); *, p<0.005. (D): Epoxomicin-mediated proteasome inhibition recapitulates Pax7 accumulation in differentiating C2C12 myoblasts. MG132 effect is shown as positive control. Right panel: quantification of Pax7 fold change (meanSEM) of three separate experiments for 1 M epoxomicin and 25 M MG132 treatments. One-way ANOVA; * and **p<0.005. (E): Proteasome inhibition results in Pax7 nuclear accumulation. Pax7 expression was determined by Western blot in cytoplasmic and nuclear fractions: (tubulin: cytoplasmic marker; histone deacetylase 2 [HDAC2]: nuclear marker), Right panel: quantification of Pax7 protein levels normalized to HDAC2 (meanSEM) of three separate experiments. Student's t-test; *, p<0.005. MG132 was used at 25 M in (B), (C), and (E). Abbreviations: DMSO, dimethyl sulfoxide; HDAC2, histone deacetylase 2.

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The Advancement of Stem Cell Technology

Welcome to the Manhattan Regenerative Medicine Medical Group, an affiliate of the California Stem Cell Treatment Center / Cell Surgical Network of Beverly Hills and Rancho Mirage, California, USA.

Our affiliated Centers utilize cutting edge advanced techniques and innovative technology to improve the health and well being of our patients.

At the Manhattan Regenerative Medicine Medical Group, we engage in the investigational use of Adult Adipose-derived Stem Cells (ADSCs) for clinical research and deployment through which patients who are suffering from diseases that may have limited treatment options have an opportunity to respond to stem cell based regenerative medicine and further advance the state of medicine, knowledge, and options for all patients.

Our expertise involves a deep commitment and long-term understanding, knowledge and experience in clinical research and the advancement of regenerative medicine. Our staff and Physicians at the Manhattan Regenerative Medicine Medical Group have been trained by the Founders and world renown specialists of the California Stem Cell Treatment Center, who have been nationally recognized for working with autologous (your own) Adult Autologous Adipose-adipose derived Stem Cells (ADSCs) providing investigational therapy to patients with various inflammatory and/or degenerative conditions.

Our Centers utilize a fat transfer technology to isolate and implant the patients ownAdult Autologous Adipose-derived Stem Cells (ADSCs) from a small quantity of fat harvested by mini-liposuction on the same day. Using technology developed in South Korea, our Centers have developed an in-office procedure to isolate a cellular medium called Stromal Vascular Fraction (SVF) which is rich in progenitor and Stem Cells. Our Founders have also worked in conjunction with a number of international organizations and physicians of great expertise to help develop our protocols for procedures. Whereas the California Stem Cell Treatment Center was developed in 2010, in 2012, the Cell Surgical Network (CSN) was formed to provide the same high level quality controlled investigational therapy both nationally and internationally.

Our Protocols are approved by an IRB (Institutional Review Board), and accordingly we are able to safely provide adipose (fat)-derived stem cell procedures on an investigational basis to our patients.The approving IRB is registered with the U.S. Department of Health, Office of Human Research Protection (OHRP). Modeled after the California Stem Cell Treatment Center, weve formed a multidisciplinary team to evaluate patients with a variety of conditions which are known to often be responsive to Stem Cell therapy.

All affiliate members of the California Stem Cell Treatment Center / Cell Surgical Network, including our Manhattan Regenerative Medicine Medical Group, contribute to the California Centers IRB approved investigational data. In this manner, we are continuously updating, researching, and learning more on how to help patients and advance the state of the art of regenerative medicine.

All patients who are interested in our investigational protocols will be evaluated by our physicians specially trained in our adipose-derived stem cell procedures and given an honest opinion as to the potential benefits and risks of stem cell therapy for their presenting condition.

The Manhattan Regenerative Medicine Medical Group is proud to be part of the only Institutional Review Board (IRB)-based stem cell procedure network in the United States that utilizes fat-transfer surgical technology. We have an array of ongoing IRB-approved protocols, and we provide care for patients with a wide variety of disorders that may benefit from adult stem cell-based regenerative therapy. At the Manhattan Regenerative Medicine Medical Group we exploit anti-inflammatory, immuno-modulatory and regenerative properties of AdultAutologous Adipose-derived Stem Cells (ADSCs) to mitigate inflammatory and degenerative diseases.

At the Manhattan Regenerative Medicine Medical Group we provide care for people suffering from diseases that may be alleviated by access to adult stem cell based regenerative treatment. Our Center utilizes a fat-transfer surgical technology to isolate and implant the patients ownAutologous Adipose-derived Stem Cells from a small quantity of fat harvested by a mini-liposuction on the same day. Please review our Medical Conditions for more information.

The California Stem Cell Treatment Center was founded in 2010 for the investigational use of stem cell procedures for degenerative conditions. The California Stem Cell Treatment Center employs a clinical research coordinator to protect our valuable data, as our vision is to perfect our methods and ultimately teach them to others.

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Manhattan Regenerative Medicine Medical Group

Sep. 3, 2015 A number of illnesses causing blindness can be cured from transplanting cells from the oral cavity. New findings make the treatment accessible to the places where the condition strikes the most ... read more Aug. 26, 2015 Compounds found in purple potatoes may help kill colon cancer stem cells and limit the spread of the cancer, according to a team of ... read more Aug. 20, 2015 Scientists have developed a novel way to engineer the growth and expansion of energy-burning 'good' fat, and then found that this fat helped reduce weight gain and lower blood glucose ... read more How Newts Can Help Osteoarthritis Patients Aug. 20, 2015 Osteoarthritis is the most common form of joint disease worldwide. Now, scientists have taken a leaf out of natures book in an attempt to develop effective stem cell treatment for osteoarthritis, ... read more Regenerating Nerve Tissue in Spinal Cord Injuries Aug. 13, 2015 Researchers are exploring a new therapy using stem cells to treat spinal cord injuries within the first 14 to 30 days of injury. The therapy uses a population of cells derived from human embryonic ... read more Newly Discovered Cells Regenerate Liver Tissue Without Forming Tumors Aug. 13, 2015 The mechanisms that allow the liver to repair and regenerate itself have long been a matter of debate. Now researchers have discovered a population of liver cells that are better at regenerating ... read more Aug. 12, 2015 Scientists have discovered metabolic rejuvenation factors in eggs. This critical finding furthers our understanding of how cellular metabolism changes during aging, and during rejuvenation after egg ... read more Can Stem Cells Cause and Cure Cancer? Aug. 12, 2015 Simply put, cancer is caused by mutations to genes within a cell that lead to abnormal cell growth. Finding out what causes that genetic mutation has been the holy grail of medical science for ... read more Why Statins Should Be Viewed as a Double-Edged Sword Aug. 12, 2015 Statins have significant cardiovascular benefits, but also serious side effects. A new study finds that statin use impairs stem cell function, which helps in slowing atherosclerosis but hinders other ... read more Researcher Studying Advances in Next-Generation Stem Cell Culture Technologies Aug. 10, 2015 A researcher is studying ways to advance the next generation of cell culture technologiesthe removal of stem cells from an organism and the controlled growth of those cells in an engineering ... read more Stem Cells Help Researchers Study the Effects of Pollution on Human Health Aug. 10, 2015 Embryonic stem cells could serve as a model to evaluate the physiological effects of environmental pollutants efficiently and cost-effectively. The use of stem cells has found another facade. In the ... read more Aug. 5, 2015 Scientists have, for the first time, found further evidence of how the differentiation of pluripotent cells is tied to and controlled by the cell cycle clock. This deeper understanding of how cells ... read more From Pluripotency to Totipotency Aug. 4, 2015 While it is already possible to obtain in vitro pluripotent cells (i.e., cells capable of generating all tissues of an embryo) from any cell type, researchers have pushed the limits of science even ... read more Precision Medicine Brought One Step Closer to the Clinic Aug. 3, 2015 A revolutionary, high-throughput, robotic platform has been designed that automates and standardizes the process of transforming patient samples into stem cells. This unique platform for the first ... read more Aug. 3, 2015 Investigators report that they have been able to drive cells to grow into muscle fibers, producing millimeter-long muscle fibers capable of contracting in a dish and multiplying in large numbers. ... read more July 30, 2015 Evaluating drug-induced liver injury is a critical part of pharmaceutical drug discovery and must be carried out on human liver cells. Now, scientists report that they produced large amounts of ... read more How a Single Molecule Turns One Immune Cell Into Another July 30, 2015 All it takes is one molecule to reprogram an antibody-producing B cell into a scavenging macrophage. This transformation is possible, new evidence shows, because the molecule (C/EBPa, a transcription ... read more July 29, 2015 A first-of-its kind prostate 'organoid' grown from human embryonic stem cells has enabled researchers to show that exposure to bisphenol A, a chemical in many plastics, can cause ... read more Scientists Identify Gene Vital for Rebuilding Intestine After Cancer Treatment July 29, 2015 A rare type of stem cell is immune to radiation damage thanks to high levels of a gene called Sox9, researchers have ... read more New Drug for Blood Cancers Now in Five Phase II Clinical Trials July 28, 2015 The safety and dosing of a new drug for treating blood cancers has now been established by a group of scientists. The drug is a small molecule inhibitor that suppresses the activity of a signaling ... read more

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What are bone marrow and hematopoietic stem cells?

Bone marrow is the soft, sponge-like material found inside bones. It contains immature cells known as hematopoietic or blood-forming stem cells. (Hematopoietic stem cells are different from embryonic stem cells. Embryonic stem cells can develop into every type of cell in the body.) Hematopoietic stem cells divide to form more blood-forming stem cells, or they mature into one of three types of blood cells: white blood cells, which fight infection; red blood cells, which carry oxygen; and platelets, which help the blood to clot. Most hematopoietic stem cells are found in the bone marrow, but some cells, called peripheral blood stem cells (PBSCs), are found in the bloodstream. Blood in the umbilical cord also contains hematopoietic stem cells. Cells from any of these sources can be used in transplants.

What are bone marrow transplantation and peripheral blood stem cell transplantation?

Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) are procedures that restore stem cells that have been destroyed by high doses of chemotherapy and/or radiation therapy. There are three types of transplants:

Why are BMT and PBSCT used in cancer treatment?

One reason BMT and PBSCT are used in cancer treatment is to make it possible for patients to receive very high doses of chemotherapy and/or radiation therapy. To understand more about why BMT and PBSCT are used, it is helpful to understand how chemotherapy and radiation therapy work.

Chemotherapy and radiation therapy generally affect cells that divide rapidly. They are used to treat cancer because cancer cells divide more often than most healthy cells. However, because bone marrow cells also divide frequently, high-dose treatments can severely damage or destroy the patients bone marrow. Without healthy bone marrow, the patient is no longer able to make the blood cells needed to carry oxygen, fight infection, and prevent bleeding. BMT and PBSCT replace stem cells destroyed by treatment. The healthy, transplanted stem cells can restore the bone marrows ability to produce the blood cells the patient needs.

In some types of leukemia, the graft-versus-tumor (GVT) effect that occurs after allogeneic BMT and PBSCT is crucial to the effectiveness of the treatment. GVT occurs when white blood cells from the donor (the graft) identify the cancer cells that remain in the patients body after the chemotherapy and/or radiation therapy (the tumor) as foreign and attack them.

What types of cancer are treated with BMT and PBSCT?

BMT and PBSCT are most commonly used in the treatment of leukemia and lymphoma. They are most effective when the leukemia or lymphoma is in remission (the signs and symptoms of cancer have disappeared). BMT and PBSCT are also used to treat other cancers such as neuroblastoma (cancer that arises in immature nerve cells and affects mostly infants and children) and multiple myeloma. Researchers are evaluating BMT and PBSCT in clinical trials (research studies) for the treatment of various types of cancer.

How are the donors stem cells matched to the patients stem cells in allogeneic or syngeneic transplantation?

To minimize potential side effects, doctors most often use transplanted stem cells that match the patients own stem cells as closely as possible. People have different sets of proteins, called human leukocyte-associated (HLA) antigens, on the surface of their cells. The set of proteins, called the HLA type, is identified by a special blood test.

In most cases, the success of allogeneic transplantation depends in part on how well the HLA antigens of the donors stem cells match those of the recipients stem cells. The higher the number of matching HLA antigens, the greater the chance that the patients body will accept the donors stem cells. In general, patients are less likely to develop a complication known as graft-versus-host disease (GVHD) if the stem cells of the donor and patient are closely matched.

Close relatives, especially brothers and sisters, are more likely than unrelated people to be HLA-matched. However, only 25 to 35 percent of patients have an HLA-matched sibling. The chances of obtaining HLA-matched stem cells from an unrelated donor are slightly better, approximately 50 percent. Among unrelated donors, HLA-matching is greatly improved when the donor and recipient have the same ethnic and racial background. Although the number of donors is increasing overall, individuals from certain ethnic and racial groups still have a lower chance of finding a matching donor. Large volunteer donor registries can assist in finding an appropriate unrelated donor.

Because identical twins have the same genes, they have the same set of HLA antigens. As a result, the patients body will accept a transplant from an identical twin. However, identical twins represent a small number of all births, so syngeneic transplantation is rare.

How is bone marrow obtained for transplantation?

The stem cells used in BMT come from the liquid center of the bone, called the marrow. In general, the procedure for obtaining bone marrow, which is called harvesting, is similar for all three types of BMTs (autologous, syngeneic, and allogeneic). The donor is given either general anesthesia, which puts the person to sleep during the procedure, or regional anesthesia, which causes loss of feeling below the waist. Needles are inserted through the skin over the pelvic (hip) bone or, in rare cases, the sternum (breastbone), and into the bone marrow to draw the marrow out of the bone. Harvesting the marrow takes about an hour.

The harvested bone marrow is then processed to remove blood and bone fragments. Harvested bone marrow can be combined with a preservative and frozen to keep the stem cells alive until they are needed. This technique is known as cryopreservation. Stem cells can be cryopreserved for many years.

How are PBSCs obtained for transplantation?

The stem cells used in PBSCT come from the bloodstream. A process called apheresis or leukapheresis is used to obtain PBSCs for transplantation. For 4 or 5 days before apheresis, the donor may be given a medication to increase the number of stem cells released into the bloodstream. In apheresis, blood is removed through a large vein in the arm or a central venous catheter (a flexible tube that is placed in a large vein in the neck, chest, or groin area). The blood goes through a machine that removes the stem cells. The blood is then returned to the donor and the collected cells are stored. Apheresis typically takes 4 to 6 hours. The stem cells are then frozen until they are given to the recipient.

How are umbilical cord stem cells obtained for transplantation?

Stem cells also may be retrieved from umbilical cord blood. For this to occur, the mother must contact a cord blood bank before the babys birth. The cord blood bank may request that she complete a questionnaire and give a small blood sample.

Cord blood banks may be public or commercial. Public cord blood banks accept donations of cord blood and may provide the donated stem cells to another matched individual in their network. In contrast, commercial cord blood banks will store the cord blood for the family, in case it is needed later for the child or another family member.

After the baby is born and the umbilical cord has been cut, blood is retrieved from the umbilical cord and placenta. This process poses minimal health risk to the mother or the child. If the mother agrees, the umbilical cord blood is processed and frozen for storage by the cord blood bank. Only a small amount of blood can be retrieved from the umbilical cord and placenta, so the collected stem cells are typically used for children or small adults.

Are any risks associated with donating bone marrow?

Because only a small amount of bone marrow is removed, donating usually does not pose any significant problems for the donor. The most serious risk associated with donating bone marrow involves the use of anesthesia during the procedure.

The area where the bone marrow was taken out may feel stiff or sore for a few days, and the donor may feel tired. Within a few weeks, the donors body replaces the donated marrow; however, the time required for a donor to recover varies. Some people are back to their usual routine within 2 or 3 days, while others may take up to 3 to 4 weeks to fully recover their strength.

Are any risks associated with donating PBSCs?

Apheresis usually causes minimal discomfort. During apheresis, the person may feel lightheadedness, chills, numbness around the lips, and cramping in the hands. Unlike bone marrow donation, PBSC donation does not require anesthesia. The medication that is given to stimulate the mobilization (release) of stem cells from the marrow into the bloodstream may cause bone and muscle aches, headaches, fatigue, nausea, vomiting, and/or difficulty sleeping. These side effects generally stop within 2 to 3 days of the last dose of the medication.

How does the patient receive the stem cells during the transplant?

After being treated with high-dose anticancer drugs and/or radiation, the patient receives the stem cells through an intravenous (IV) line just like a blood transfusion. This part of the transplant takes 1 to 5 hours.

Are any special measures taken when the cancer patient is also the donor (autologous transplant)?

The stem cells used for autologous transplantation must be relatively free of cancer cells. The harvested cells can sometimes be treated before transplantation in a process known as purging to get rid of cancer cells. This process can remove some cancer cells from the harvested cells and minimize the chance that cancer will come back. Because purging may damage some healthy stem cells, more cells are obtained from the patient before the transplant so that enough healthy stem cells will remain after purging.

What happens after the stem cells have been transplanted to the patient?

After entering the bloodstream, the stem cells travel to the bone marrow, where they begin to produce new white blood cells, red blood cells, and platelets in a process known as engraftment. Engraftment usually occurs within about 2 to 4 weeks after transplantation. Doctors monitor it by checking blood counts on a frequent basis. Complete recovery of immune function takes much longer, howeverup to several months for autologous transplant recipients and 1 to 2 years for patients receiving allogeneic or syngeneic transplants. Doctors evaluate the results of various blood tests to confirm that new blood cells are being produced and that the cancer has not returned. Bone marrow aspiration (the removal of a small sample of bone marrow through a needle for examination under a microscope) can also help doctors determine how well the new marrow is working.

What are the possible side effects of BMT and PBSCT?

The major risk of both treatments is an increased susceptibility to infection and bleeding as a result of the high-dose cancer treatment. Doctors may give the patient antibiotics to prevent or treat infection. They may also give the patient transfusions of platelets to prevent bleeding and red blood cells to treat anemia. Patients who undergo BMT and PBSCT may experience short-term side effects such as nausea, vomiting, fatigue, loss of appetite, mouth sores, hair loss, and skin reactions.

Potential long-term risks include complications of the pretransplant chemotherapy and radiation therapy, such as infertility (the inability to produce children); cataracts (clouding of the lens of the eye, which causes loss of vision); secondary (new) cancers; and damage to the liver, kidneys, lungs, and/or heart.

With allogeneic transplants, GVHD sometimes develops when white blood cells from the donor (the graft) identify cells in the patients body (the host) as foreign and attack them. The most commonly damaged organs are the skin, liver, and intestines. This complication can develop within a few weeks of the transplant (acute GVHD) or much later (chronic GVHD). To prevent this complication, the patient may receive medications that suppress the immune system. Additionally, the donated stem cells can be treated to remove the white blood cells that cause GVHD in a process called T-cell depletion. If GVHD develops, it can be very serious and is treated with steroids or other immunosuppressive agents. GVHD can be difficult to treat, but some studies suggest that patients with leukemia who develop GVHD are less likely to have the cancer come back. Clinical trials are being conducted to find ways to prevent and treat GVHD.

The likelihood and severity of complications are specific to the patients treatment and should be discussed with the patients doctor.

What is a mini-transplant?

A mini-transplant (also called a non-myeloablative or reduced-intensity transplant) is a type of allogeneic transplant. This approach is being studied in clinical trials for the treatment of several types of cancer, including leukemia, lymphoma, multiple myeloma, and other cancers of the blood.

A mini-transplant uses lower, less toxic doses of chemotherapy and/or radiation to prepare the patient for an allogeneic transplant. The use of lower doses of anticancer drugs and radiation eliminates some, but not all, of the patients bone marrow. It also reduces the number of cancer cells and suppresses the patients immune system to prevent rejection of the transplant.

Unlike traditional BMT or PBSCT, cells from both the donor and the patient may exist in the patients body for some time after a mini-transplant. Once the cells from the donor begin to engraft, they may cause the GVT effect and work to destroy the cancer cells that were not eliminated by the anticancer drugs and/or radiation. To boost the GVT effect, the patient may be given an injection of the donors white blood cells. This procedure is called a donor lymphocyte infusion.

What is a tandem transplant?

A tandem transplant is a type of autologous transplant. This method is being studied in clinical trials for the treatment of several types of cancer, including multiple myeloma and germ cell cancer. During a tandem transplant, a patient receives two sequential courses of high-dose chemotherapy with stem cell transplant. Typically, the two courses are given several weeks to several months apart. Researchers hope that this method can prevent the cancer from recurring (coming back) at a later time.

How do patients cover the cost of BMT or PBSCT?

Advances in treatment methods, including the use of PBSCT, have reduced the amount of time many patients must spend in the hospital by speeding recovery. This shorter recovery time has brought about a reduction in cost. However, because BMT and PBSCT are complicated technical procedures, they are very expensive. Many health insurance companies cover some of the costs of transplantation for certain types of cancer. Insurers may also cover a portion of the costs if special care is required when the patient returns home.

There are options for relieving the financial burden associated with BMT and PBSCT. A hospital social worker is a valuable resource in planning for these financial needs. Federal government programs and local service organizations may also be able to help.

NCIs Cancer Information Service (CIS) can provide patients and their families with additional information about sources of financial assistance at 18004226237 (18004CANCER). NCI is part of the National Institutes of Health.

What are the costs of donating bone marrow, PBSCs, or umbilical cord blood?

All medical costs for the donation procedure are covered by Be The Match, or by the patients medical insurance, as are travel expenses and other non-medical costs. The only costs to the donor might be time taken off from work.

A woman can donate her babys umbilical cord blood to public cord blood banks at no charge. However, commercial blood banks do charge varying fees to store umbilical cord blood for the private use of the patient or his or her family.

Where can people get more information about potential donors and transplant centers?

The National Marrow Donor Program (NMDP), a nonprofit organization, manages the worlds largest registry of more than 11 million potential donors and cord blood units. The NMDP operates Be The Match, which helps connect patients with matching donors.

A list of U.S. transplant centers that perform allogeneic transplants can be found at BeTheMatch.org/access. The list includes descriptions of the centers, their transplant experience, and survival statistics, as well as financial and contact information.

Where can people get more information about clinical trials of BMT and PBSCT?

Clinical trials that include BMT and PBSCT are a treatment option for some patients. Information about ongoing clinical trials is available from NCIs CIS at 18004226237 (18004CANCER) or on NCIs website.

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Blood-Forming Stem Cell Transplants - National Cancer ...

Stem cell facts Stem cells are primitive cells that have the potential to differentiate, or develop into, a variety of specific cell types. There are different types of stem cells based upon their origin and ability to differentiate. Bone marrow transplantation is an example of a stem cell therapy that is in widespread use. Research is underway to determine whether stem cell therapy may be useful in treating a wide variety of conditions, including diabetes, heart disease, Parkinson's disease, and spinal cord injury. What are stem cells?

Stem cells are cells that have the potential to develop into many different or specialized cell types. Stem cells can be thought of as primitive, "unspecialized" cells that are able to divide and become specialized cells of the body such as liver cells, muscle cells, blood cells, and other cells with specific functions. Stem cells are referred to as "undifferentiated" cells because they have not yet committed to a developmental path that will form a specific tissue or organ. The process of changing into a specific cell type is known as differentiation. In some areas of the body, stem cells divide regularly to renew and repair the existing tissue. The bone marrow and gastrointestinal tract are examples areas in which stem cells function to renew and repair tissue.

The best and most readily understood example of a stem cell in humans is that of the fertilized egg, or zygote. A zygote is a single cell that is formed by the union of a sperm and ovum. The sperm and the ovum each carry half of the genetic material required to form a new individual. Once that single cell or zygote starts dividing, it is known as an embryo. One cell becomes two, two become four, four become eight, eight to sixteen, and so on; doubling rapidly until it ultimately creates the entire sophisticated organism. That organism, a person, is an immensely complicated structure consisting of many, many, billions of cells with functions as diverse as those of your eyes, your heart, your immune system, the color of your skin, your brain, etc. All of the specialized cells that make up these body systems are descendants of the original zygote, a stem cell with the potential to ultimately develop into all kinds of body cells. The cells of a zygote are totipotent, meaning that they have the capacity to develop into any type of cell in the body.

The process by which stem cells commit to become differentiated, or specialized, cells is complex and involves the regulation of gene expression. Research is ongoing to further understand the molecular events and controls necessary for stem cells to become specialized cell types.

Medically Reviewed by a Doctor on 1/23/2014

Stem Cells - Experience Question: Please describe your experience with stem cells.

Stem Cells - Umbilical Cord Question: Have you had your child's umbilical cord blood banked? Please share your experience.

Stem Cells - Available Therapies Question: Did you or someone you know have stem cell therapy? Please discuss your experience.

Medical Author:

Melissa Conrad Stppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Stem Cells: Get Facts on Uses, Types, and Therapies