Regenerative medicine – Wikipedia, the free encyclopedia

Regenerative medicine is the "process of replacing or regenerating human cells, tissues or organs to restore or establish normal function".[1] This field holds the promise of regenerating damaged tissues and organs in the body by replacing damaged tissue and/or by stimulating the body's own repair mechanisms to heal previously irreparable tissues or organs.

Regenerative medicine also includes the possibility of growing tissues and organs in the laboratory and safely implant them when the body cannot heal itself This can potentially solves the problem of the shortage of organs available for donation, and the problem of organ transplant rejection if the organ's cells are derived from the patient's own tissue or cells.[2][3][4]

Widely attributed to having first been coined by William Haseltine (founder of Human Genome Sciences),[5] the term "Regenerative Medicine" was first found in a 1992 article on hospital administration by Leland Kaiser. Kaisers paper closes with a series of short paragraphs on future technologies that will impact hospitals. One such paragraph had Regenerative Medicine as a bold print title and went on to state, A new branch of medicine will develop that attempts to change the course of chronic disease and in many instances will regenerate tired and failing organ systems.[6][7]

Regenerative medicine refers to a group of biomedical approaches to clinical therapies that may involve the use of stem cells.[8] Examples include the injection of stem cells or progenitor cells (cell therapies); the induction of regeneration by biologically active molecules administered alone or as a secretion by infused cells (immunomodulation therapy); and transplantation of in vitro grown organs and tissues (Tissue engineering).[9][10]

A form of regenerative medicine that recently made it into clinical practice, is the use of heparan sulfate analogues on (chronic) wound healing. Heparan sulfate analogues replace degraded heparan sulfate at the wound site. They assist the damaged tissue to heal itself by repositioning growth factors and cytokines back into the damaged extracellular matrix.[11][12][13] For example, in abdominal wall reconstruction (like inguinal hernia repair), biologic meshes are being used with some success.

At the Wake Forest Institute for Regenerative Medicine, in North Carolina, Dr. Anthony Atala and his colleagues have successfully extracted muscle and bladder cells from several patients' bodies, cultivated these cells in petri dishes, and then layered the cells in three-dimensional molds that resembled the shapes of the bladders. Within weeks, the cells in the molds began functioning as regular bladders which were then implanted back into the patients' bodies.[14] The team is currently[when?] working on re-growing over 22 other different organs including the liver, heart, kidneys and testicles.[15]

From 1995 to 1998 Michael D. West, PhD, organized and managed the research between Geron Corporation and its academic collaborators James Thomson at the University of Wisconsin-Madison and John Gearhart of Johns Hopkins University that led to the first isolation of human embryonic stem and human embryonic germ cells.[16]

Dr. Stephen Badylak, a Research Professor in the Department of Surgery and director of Tissue Engineering at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh, developed a process for scraping cells from the lining of a pig's bladder, decellularizing (removing cells to leave a clean extracellular structure) the tissue and then drying it to become a sheet or a powder. This cellular matrix powder was used to regrow the finger of Lee Spievak, who had severed half an inch of his finger after getting it caught in a propeller of a model plane.[17][18][19][dubious discuss] As of 2011, this new technology is being employed by the military to U.S. war veterans in Texas, as well as to some civilian patients. Nicknamed "pixie-dust," the powdered extracellular matrix is being used success to regenerate tissue lost and damaged due to traumatic injuries.

In June 2008, at the Hospital Clnic de Barcelona, Professor Paolo Macchiarini and his team, of the University of Barcelona, performed the first tissue engineered trachea (wind pipe) transplantation. Adult stem cells were extracted from the patient's bone marrow, grown into a large population, and matured into cartilage cells, or chondrocytes, using an adaptive method originally devised for treating osteoarthritis. The team then seeded the newly grown chondrocytes, as well as epithileal cells, into a decellularised (free of donor cells) tracheal segment that was donated from a 51 year old transplant donor who had died of cerebral hemorrhage. After four days of seeding, the graft was used to replace the patient's left main bronchus. After one month, a biopsy elicited local bleeding, indicating that the blood vessels had already grown back successfully.[20][21]

In 2009 the SENS Foundation was launched, with its stated aim as "the application of regenerative medicine defined to include the repair of living cells and extracellular material in situ to the diseases and disabilities of ageing." [22]

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Regenerative medicine - Wikipedia, the free encyclopedia