Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Stem Cells. May 26, 2015; 7(4): 669-680
Published online May 26, 2015. doi: 10.4252/wjsc.v7.i4.669
Spermatogonial stem cells: Current biotechnological advances in reproduction and regenerative medicine
Pedro Manuel Aponte
Pedro Manuel Aponte, AGROCALIDAD/Project Prometeo - SENESCYT, Quito 170184, Ecuador
Author contributions: Aponte PM solely contributed to this paper.
Conflict-of-interest: The author has no commercial, personal, political, intellectual, or religious conflicts of interest to declare regarding this manuscript
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Pedro Manuel Aponte, DVM, PhD, Scientific Adviser at AGROCALIDAD/Project Prometeo - SENESCYT, Av. 9 de Octubre N22-48 y Jerónimo Carrión, Casa Patrimonial, Quito 170184, Ecuador. apontep@gmail.com
Telephone: +593-2-2372844 Fax: +593-2-2372844
Received: January 28, 2015
Peer-review started: January 31, 2015
First decision: February 7, 2015
Revised: March 13, 2015
Accepted: April 10, 2015
Article in press: April 14, 2015
Published online: May 26, 2015

Spermatogonial stem cells (SSCs) are the germ stem cells of the seminiferous epithelium in the testis. Through the process of spermatogenesis, they produce sperm while concomitantly keeping their cellular pool constant through self-renewal. SSC biology offers important applications for animal reproduction and overcoming human disease through regenerative therapies. To this end, several techniques involving SSCs have been developed and will be covered in this article. SSCs convey genetic information to the next generation, a property that can be exploited for gene targeting. Additionally, SSCs can be induced to become embryonic stem cell-like pluripotent cells in vitro. Updates on SSC transplantation techniques with related applications, such as fertility restoration and preservation of endangered species, are also covered on this article. SSC suspensions can be transplanted to the testis of an animal and this has given the basis for SSC functional assays. This procedure has proven technically demanding in large animals and men. In parallel, testis tissue xenografting, another transplantation technique, was developed and resulted in sperm production in testis explants grafted into ectopical locations in foreign species. Since SSC culture holds a pivotal role in SSC biotechnologies, current advances are overviewed. Finally, spermatogenesis in vitro, already demonstrated in mice, offers great promises to cope with reproductive issues in the farm animal industry and human clinical applications.

Keywords: Cell culture, Spermatogonial stem cells, Spermatogenesis, Pluripotency, Transplantation, Fertility

Core tip: This article reviews the current body of knowledge on biotechnological applications of spermatogonial stem cells (SSCs). SSCs are the founding adult germ stem cells of the sperm producing process spermatogenesis. SSCs belong to the male germline and can be expanded in vitro in several species. Through mechanisms not fully understood they can derive pluripotent stem cells in vitro. Thus, they can be genetically modified with some advantages over embryonic stem cell-based technologies. SSCs can be transplanted to homotopical or ectopical locations, offering great potentials in fertility related issues and regenerative clinical applications in domestic or wild animals and men.