Cryopreservation of Ovarian Tissue in Pediatric Patients

Abstract

Cancer treatments improve the survival rate of children and adolescents; however chemo- and radiotherapy result in gonadal damage leading to acute ovarian failure and sterility. Ovarian tissue cryopreservation allows long-term storage of primordial follicles and represents the only possibility of preserving the potential fertility in prepubertal girls. The aim of the present study is to describe our experience in ovarian tissue cryopreservation in 45 pediatric patients. The number of follicles per square millimeter of the overall section area and follicle quality were evaluated histologically. A strong negative correlation was found between age and follicular density in patients both prior to and after chemotherapy (P < 0.0001). Damage in follicular quality, that is, increased oocyte vacuolization and detachment of the oocyte from granulosa cells, was found after chemotherapy. Ovarian tissue cryopreservation, preferably performed before initiation of chemotherapy, should be offered to pediatric patients, including prepubertal girls, at risk of sterility.

Number and density of equine preantral follicles in different ovarian histological section thicknesses

“…Several studies, regardless of species, have reported a large variation in the number of preantral follicles per ovary (human: 2700-79,600 [20]; swine: 67,599-291,898 [29]; bovine: 59,798-78,820 [30]; ovine: 7333-44,633 [21]). In addition, similarly to our novel finding in mares, a high heterogeneity in density of preantral follicles per mm 2 has been reported for several species (buffalo: 6-35 [31], squirrel monkeys: 0.01-303 [32], women: 0.6-159 [33], sheep: 0-52 [22]). …”

Fertility preservation in Turner syndrome

“…Indeed, hypoxia and hyperactivation of follicular growth (48-51) account for the substantial loss of primordial follicles and reduction of oocyte quality after transplantation (52). Since primordial follicles are the most resistant to ischemic damage after grafting (53), the chance of restoring fertility is related to the number and quality of follicles endowed within the transplanted cortical tissue (54). Therefore, in candidates for ovarian tissue cryopreservation, the quantity of ovarian tissue removed should be influenced by the expected probability of POI (55).…”

Pubertal induction in hypogonadism: Current approaches including use of gonadotrophins

“…Consideration for ovum salvage is now a realistic possibility, in that successful pregnancies have been achieved using stored unfertilized ova for other conditions of compromised fertility [25,26]. In Turner syndrome, potential for causing loss of current ovarian function by ovarian biopsy, risks of future foetal genetic or structural abnormalities and the possibility of failure of the intervention must all be considered [27,28].…”

“…Reports of successful pregnancies after harvest or preservation of immature, unfertilized oocytes or whole ovary has indicated a need to consider harvesting oocytes for girls undergoing chemotherapy or those with an ongoing loss of ova [25,64,65].…”