Ovarian tissue preservation, present and clinical perspectives.

Ovarian tissue preservation and transplantation are intended for women undergoing aggressive regimens of chemical and/or radiological therapy, bone marrow transplantation or stem cell transplantation. Main indications for the procedure are neoplastic diseases and autoimmune disorders. The first live human birth after ovarian tissue autotransplantation was successfully done in 2002. Cryopreserved ovarian tissue can be autografted either orthotopically or heterotopically. Neovascularization of the implanted tissue is essential for the procedure. Vascular transplantation seems to be the best approach for avoiding follicular loss and extending the lifespan of the ovarian grafts. The procedure, regardless of whether ortho- or heterotopic, is connected with a risk of reimplantation of neoplastic cells. This can be minimized by multiple ovary biopsies, thorough histological examination and molecular genetic techniques. Introducing ovarian tissue transplantation into clinical practice requires many problems to be solved. Standardization of the freeze-thaw protocol is one of the most important issues. Solving the problem of transient graft ischemia is also essential. Eventually, the future safety of the method requires the development of efficient tests to detect the presence of neoplastic cells in the transplanted tissue.