title: Spermatogonial stem cells: Progress and prospects.
abstract: Twenty years ago, the transplantation of spermatogonial stem cells (SSCs) from a mouse to other recipient mice was shown to be feasible, which clearly demonstrated the functional identity of SSCs. Since then, several important new findings and other technical developments have followed, which included a new hypothesis on their cell kinetics and spermatogonial hierarchy in the testis, a culture method allowing their self-renewal and proliferation, a testis tissue organ culture method, which induced their complete differentiation up to sperm, and the in vitro induction of germ cells from embryonic stem cells and induced pluripotent stem cells. These advancements reinforced or advanced our understanding of this unique cell. Nonetheless, there are many unresolved questions in the study of spermatogonial stem cells and a long road remains until these cells can be used clinically in reproductive medicine.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Komeya
authors.affiliation: Department of Urology, Graduate School of Medicine, Yokohama City University; Laboratory of Proteomics, Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama 236 0004, Japan, .
authors.forename: Takehiko
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000637:transplantation; D000818:Animals; D006801:Humans; D008297:Male; D051379:Mice; D013091:Spermatogenesis / Q000502:physiology*; D013093:Spermatogonia / Q000166:cytology* / Q000637:transplantation; D013737:Testis / Q000166:cytology*