Transplantation of cryopreserved ovarian tissues

Introduction The concept of transplantation in reproductive medicine has been considered by physicians and scientists for many years and it is now over a century since the first human ovarian graft was performed. The ovary is well suited for transplantation since the most abundant primordial follicles are present in the periphery and are the first to benefit from revascularization. In addition, ovarian follicles may be resistant to ischemia as they normally develop within an avascular epithelium and a relatively hypoxic environment. Ovarian tissue transplantation has become clinically feasible with advances in cryobiology and the effective cryopreservation of ovarian tissue. Today, ovarian tissue harvesting is performed by a simple laparoscopic procedure. In addition, accurate patient monitoring is possible before and after transplantation using endocrine studies and sonography imaging. For patients, transplantation of ovarian tissue has become an attractive option to overcome the risk of pending premature menopause caused by various clinical conditions. Among these clinical treatments, radiotherapy and curative chemotherapy, used for cancer treatment, often pose a threat to fertility, as ovarian damage is a common long-term side effect. For these patients, harvesting and cryopreservation of ovarian tissue before commencing potentially sterilizing chemotherapy has been practiced since the mid 1990s. In addition, the transplantation of thawed tissue has been shown to successfully restore their fertility. This chapter describes different aspects of ovarian tissue transplantation including history, basic experiments, and the results of clinical studies.