Isolation and Characterization of Pluripotent Human Spermatogonial Stem Cell-Derived Cells NINA KOSSACK,a,b JUANITO MENESES,c SHAI SHEFI,d,e HA NAM NGUYEN,a SHAWN CHAVEZ,a

Several reports have documented the derivation of pluripo-tent cells (multipotent germline stem cells) from spermato-gonial stem cells obtained from the adult mouse testis. These spermatogonia-derived stem cells express embryonic stem cell markers and differentiate to the three primary germ layers, as well as the germline. Data indicate that deriva-tion may involve reprogramming of endogenous sper-matogonia in culture. Here, we report the derivation of human multipotent germline stem cells (hMGSCs) from a testis biopsy. The cells express distinct markers of pluri-potency, form embryoid bodies that contain derivatives of all three germ layers, maintain a normal XY karyotype, are hypomethylated at the H19 locus, and express high levels of telomerase. Teratoma assays indicate the pres-ence of human cells 8 weeks post-transplantation but limited teratoma formation. Thus, these data suggest the potential to derive pluripotent cells from human testis biopsies but indicate a need for novel strategies to opti-mize hMGSC culture conditions and reprogramming. STEM CELLS 2009;27:138–149 Disclosure of potential conflicts of interest is found at the end of this article