title: Germ cell transplantation into X-irradiated monkey testes.
abstract: BACKGROUND
  An intense debate is ongoing regarding options for fertility protection in oncological patients. Germ cell transplantation has been applied to restore mouse spermatogenesis. Here, an attempt to apply autologous germ cell transplantation to a primate animal model is described.
  
  
  METHODS
  Five adult male cynomolgus monkeys were biopsied to retrieve and cryopreserve germ cells before both testes were irradiated (dose 2 Gy). Six weeks later, each monkey received an infusion of its own cell suspension into the right testis, while the left testes were infused with saline. Testis size, sperm counts and serum concentrations of inhibin, FSH and testosterone were analysed weekly for 9 months. Spermatogenic recovery was determined histologically at the end of the study.
  
  
  RESULTS
  In four monkeys, the germ cell-infused right testes showed a slight to moderate increase in the rate of regrowth in comparison with the left testes. In two monkeys the right testis proceeded to recover more prominently, resulting in larger right testis volumes and better or full spermatogenic recovery at the study end. Restoration of spermatogenesis occurred as an all-or-nothing event. Inhibin B concentrations increased, while FSH and testosterone concentrations decreased with testicular regrowth. Sperm counts did not recover.
  
  
  CONCLUSIONS
  The present study demonstrates the immaturity and complexity of germ cell transplantation as a clinical approach.
authors.affiliation: Institute of Reproductive Medicine of the University, Münster, Germany. schlats@uni-muenster.de
authors.forename: S
authors.initials: S
authors.lastname: Schlatt
authors.forename: L
authors.initials: L
authors.lastname: Foppiani
authors.forename: C
authors.initials: C
authors.lastname: Rolf
authors.forename: G F
authors.initials: GF
authors.lastname: Weinbauer
authors.forename: E
authors.initials: E
authors.lastname: Nieschlag
mesh_terms: D000818:Animals; D001835:Body Weight; D001973:Bromodeoxyuridine / Q000032:analysis; D005434:Flow Cytometry; D005640:Follicle Stimulating Hormone / Q000097:blood; D007150:Immunohistochemistry; D007265:Inhibins / Q000097:blood; D007700:Kinetics; D008252:Macaca fascicularis; D008297:Male; D013076:Sperm Count; D013091:Spermatogenesis; D013094:Spermatozoa / Q000637:transplantation*; D013737:Testis / Q000033:anatomy & histology / Q000528:radiation effects*; D013739:Testosterone / Q000097:blood; D014965:X-Rays
chemical_list: D013739:Testosterone; D007265:Inhibins; D005640:Follicle Stimulating Hormone; D001973:Bromodeoxyuridine