ScienceDaily (Nov. 1, 2012)  An    injection of banked sperm-producing stem cells can restore    fertility to male primates who become sterile due to cancer    drug side effects, according to researchers at the University    of Pittsburgh School of Medicine and Magee-Womens Research    Institute. In their animal study, which was published today in    Cell Stem Cell, previously frozen stem cells restored    production of sperm that successfully fertilized eggs to    produce early embryos.  
    Some cancer drugs work by destroying rapidly dividing cells. As    it is not possible to discriminate between cancer cells and    other rapidly dividing cells in the body, the precursor cells    involved in making sperm can be inadvertently wiped out leaving    the patient infertile, said senior investigator Kyle Orwig,    Ph.D., associate professor, Department of Obstetrics,    Gynecology and Reproductive Medicine, Pitt School of Medicine,    and an investigator at Magee-Womens Research Institute.  
    "Men can bank sperm before they have cancer treatment if they    hope to have biological children later in their lives," he    said. "But that is not an option for young boys who haven't    gone through puberty, can't provide a sperm sample, and are    many years away from thinking about having babies."  
    Even very young boys, though, have spermatogonial stem cells in    their testicular tissue that are poised to begin producing    sperm during puberty. To see whether it was possible to restore    fertility using these cells, Dr. Orwig and his team biopsied    the testes of prepubertal and adult male macaque monkeys and    cryopreserved the cells from the small samples. The monkeys    were then treated with chemotherapy agents known to impair    fertility.  
    A few months after chemotherapy treatment, the team    re-introduced each monkey's own spermatogonial stem cells back    in to his testes using an ultrasound-guided technique. Sperm    production was established from transplanted cells in nine out    of 12 adult animals and three out of five prepubertal animals    after they reached maturity. In another test, spermatogonial    stem cells from other unrelated monkeys were transplanted into    infertile animals, which created sperm with the DNA fingerprint    of the donor to allow easy tracking of their origin. In lab    tests, sperm from transplant recipients successfully fertilized    81 eggs, leading to embryos that developed to the morula and    blastocyst stages, which are the stages that normally precede    implantion in the mother's uterus. Donor parentage was    confirmed in seven of the embryos.  
    "This study demonstrates that spermatogonial stem cells from    higher primates can be frozen and thawed without losing their    activity, and that they can be transplanted to produce    functional sperm that are able to fertilize eggs and give rise    to early embryos," Dr. Orwig said.  
    The findings are encouraging because several centers in the    U.S. and abroad already are banking testicular tissue for boys    in anticipation that new stem cell-based therapies will be    available in the future to help them achieve pregnancy and have    their own biological children.  
    "These patients and their families are the pioneers that    inspire our research and help drive the development of new    medical breakthroughs," Dr. Orwig said. He directs the    Fertility Preservation Program in Pittsburgh, a unique    collaboration between Magee-Womens Research Institute,    Magee-Womens Hospital of UPMC, Children's Hospital of    Pittsburgh of UPMC, and the University of Pittsburgh Cancer    Institute that offers education and treatment options for    children as well as adult men and women who are at risk of    becoming infertile due to medical problems including cancer.  
    "Many questions remain to be answered," Dr. Orwig noted.    "Should we re-introduce the spermatogonial cells as soon as    treatment is over, or wait until the patient is considered    cured of his disease, or when he is ready to start a family?    How do we eliminate the risk of cancer recurrence if we give    back untreated cells that might include cancer cells? These are    issues we still must work through, but this study does show us    the concept is feasible."  
    Co-authors of the paper include lead author Brian P. Hermann,    Ph.D., David K. Cooper, M.D., Ph.D., Angus W. Thomson, Ph.D.,    D. Sc., Gerald P. Schatten, Ph.D., and others from the    University of Pittsburgh School of Medicine, as well as    collaborators from the Oregon National Primate Research Center,    University of California at Davis, ITxM Diagnostics in    Pittsburgh, and CaridianBCT.  
Link:
Male fertility can be restored after cancer treatment, researchers find