New steps towards the artificial ovary

Objective: The aim of this study was to create an artificial ovary to provide an alternative way of restoring fertility in patients who cannot undergo transplantation of cryopreserved ovarian tissue due to the threat of reintroducing malignant cells. Materials and methods: Ovaries from six-week-old female NMRI mice were removed for isolation of preantral follicles and ovarian cells (OCs). Thereafter, isolated follicles and OCs were encapsulated in two fibrin matrices containing low concentrations of fibrinogen (mg/ml) and thrombin (IU/mL) (F/T: F12.5/T1 and F25/T4) and autografted to mice. After one week, follicular density and development, OC survival and proliferation, inflammatory response and vascularization were evaluated. Results: After grafting, the follicle recovery rate ranged between 30.8% (F25/T4) and 31.8% (F12.5/T1). With both fibrin formulations, all follicles were found to be alive or minimally damaged, as demonstrated by TUNEL assay, and at the growth stage (primary, secondary and antral), confirmed by Ki67 immunostaining. Isolated OCs also survived and proliferated after grafting, as evidenced by less than 1% of apoptotic cells and a high proportion of Ki67-positive cells. Vessels were found in both fibrin formulations and the global vascular surface area varied from 1.35% (F25/T4) to 1.88% (F12.5/T1). Numerous CD45-positive cells were also observed in these two combinations. Conclusions: The present study is the first to show survival and growth of isolated murine ovarian follicles one week after autotransplantation of isolated OCs in a fibrin scaffold. The results indicate that fibrin is a promising candidate as a matrix for the construction of an artificial ovary. Xenotransplantation of isolated human follicles and OCs is the necessary next step to validate these findings