Stem Cell Therapy for Male Infertility: A Review

Infertility affects 15% of couples in reproductive age world-wide and male factor is solely responsible in about 50% of the cases and contributory in 30-40% of cases. Spermatogonial stem cells (SSCs) are small self-renewing cells found in the basal compartment of seminiferous tubules where they form the foundation of spermatogenesis and are required for the continuous production of sperm. Transplantation of spermatogonial stem cells results in a donor derived sperm production and fertility in rodent and non-rodent species like Goat. Transplantation of cryopreserved spermatogonial stem cells could help oncology patients undergoing radiotherapy or chemotherapy by prior isolation of the SSCs and transplantation after treatment. Induced pluripotent stem cells also have the ability to differentiate into late stage germ cells. The efficacy and safety of SSCs transplantation showed that offspring produced did not show any morphological differences or alteration of genetic material but is most effective through assisted reproduction and better on young/immature Animals. The transfer of germ cells through micro-injection of seminiferous tubules and cannulation of efferent ducts is most effective on rodent testis while injection into the rete testis guided by ultrasound was reported to be the best technique in higher Animals (Bulls and Apes). Researches are still ongoing to get a safe and successful method of SSCs transplantation with no or less side effects on humans. Keywords: Cryopreserved, Pluripotent, self-renewing, Spermatogonia, and Spermatogenesis