A preclinical study in which spermatogonial stem cells (SSCs) were used to overcome male infertility could be particularly meaningful for prepubertal boys who have been rendered infertile by chemotherapy or radiotherapy.
“This is the first study to demonstrate that transplanted spermatogonial stem cells can produce functional sperm in higher primates,” affirmed senior study author Kyle E. Orwig, PhD, of the University of Pittsburgh (Pennsylvania) and Magee-Womens Research Institute, also in Pittsburgh, in a statement issued by Cell Press. The findings appear in Cell Press’s Cell Stem Cell (2012;11:715-726).
As Orwig and coauthors pointed out in their report, chemotherapy and other radiation treatments for cancer or other conditions can permanently damage fertility. Although adult male patients have the option of cryoperserving sperm before treatment, no standard-of-care options exist for preserving the fertility of prepubertal boys who are not yet producing mature sperm.
Research has indicated it may be possible to isolate and freeze SSCs obtained from testicular biopsy prior to gonadotoxic therapy, and reintroduce the cells into the testes after treatment ends and after the patient has reached sexual maturity. This approach has worked in a range of animal models, but studies in large animals have mainly used radiation therapy to cause infertility.
In the current study, Orwig’s team cryopreserved SSCs from prepubertal and adult male macaque monkeys. The monkeys subsequently underwent chemotherapy that left them infertile. After treatment, the investigators injected the SSCs into the testes of the animals, and found that the cells produced sperm in the majority. In addition, the SSC-derived sperm of one monkey was capable of fertilizing egg cells and producing embryos that developed normally.
In another test, SSCs from other monkeys were transplanted into infertile animals, with successful results.
The findings are encouraging because several centers in the United States and abroad already are banking testicular tissue for boys in anticipation that new stem-cell-based therapies will be developed to help these patients eventually father children.