title: Options for fertility preservation in prepubertal boys.
abstract: BACKGROUND
  Fertility in adult life may be severely impaired by gonadotoxic therapies. For young boys who do not yet produce spermatozoa, cryopreservation of immature testicular tissue (ITT) is an option to preserve their fertility, albeit still experimental. This paper covers current options for ITT cryopreservation and fertility restoration.
  
  
  METHODS
  Relevant studies were identified by an extensive Medline search of English and French language articles. Search terms were: gonadotoxicity, cytoprotection, cryopreservation, ITT, spermatogonia, testicular transplantation, testicular grafting and in vitro maturation (IVM).
  
  
  RESULTS
  Although no effective gonadoprotective drug is yet available for in vivo spermatogonial stem cell protection in humans, current evidence supports the feasibility of ITT cryopreservation before gonadotoxic treatment with a view to fertility preservation. Controlled slow freezing with dimethyl sulfoxide allows survival and proliferation of human spermatogonia after xenotransplantation, but only partial differentiation. Animal data look promising, since healthy offspring have been obtained after transplantation of frozen testicular cell suspensions or tissue pieces. However, none of the fertility restoration options from frozen tissue, i.e. cell suspension transplantation, tissue grafting and IVM have proved efficient and safe in humans as yet.
  
  
  CONCLUSIONS
  While additional evidence is required to define optimal conditions for ITT cryopreservation with a view to transplantation or IVM, the putative indications for such techniques, as well as their limitations according to disease, are outlined.
authors.affiliation: Department of Gynecology, Université Catholique de Louvain, Cliniques Universitaires St Luc, Avenue Hippocrate 10, Brussels, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Wyns
authors.forename: Mara
authors.initials: M
authors.lastname: Curaba
authors.forename: Bernard
authors.initials: B
authors.lastname: Vanabelle
authors.forename: Anne
authors.initials: A
authors.lastname: Van Langendonckt
authors.forename: Jacques
authors.initials: J
authors.lastname: Donnez
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D015925:Cryopreservation / Q000379:methods / Q000639:trends; D019610:Cytoprotection; D005298:Fertility / Q000187:drug effects* / Q000528:radiation effects*; D005854:Germ Cells / Q000637:transplantation; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis / Q000517:prevention & control*; D008297:Male; D011379:Prognosis; D011878:Radiotherapy / Q000009:adverse effects; D013737:Testis / Q000187:drug effects* / Q000528:radiation effects* / Q000637:transplantation; D035703:Therapies, Investigational / Q000009:adverse effects / Q000379:methods / Q000639:trends; D014015:Tissue Banks
chemical_list: D000970:Antineoplastic Agents