In Vitro Generation of Oocytes from Ovarian Stem Cells (OSCs): In Search of Major Evidence

Abstract

The existence of ovarian stem cells (OSCs) in women as well as their physiological role in post-menopausal age are disputed. However, accumulating evidence demonstrated that, besides the animal models including primarily mice, even in adult women putative OSCs obtained from ovarian cortex are capable to differentiate in vitro into oocyte-like cells (OLCs) expressing molecular markers typical of terminal stage of oogonial cell lineage. Recent studies describe that, similarly to mature oocytes, the OSC-derived OLCs also contain haploid karyotype. As proof of concept of their stem commitment, OSCs from mice differentiated to oocytes in vitro are suitable to be fertilized and implanted in sterilized animals resulting in embryo development. Despite enthusiasm for these data, which definitely require extended confirmation before considering potential application in humans for treatment of ovarian insufficiency, OSCs appear suitable for other clinical uses, restoring the endocrine derangements in premature ovarian failure or for fertility preservation in oncologic patients after anti-cancer treatments. In this context, the selection of viable oocytes generated from OSCs before chemotherapy protocols would overcome the potential adjunct oncogenic risk in women bearing hormone-dependent tumors who are repeatedly stimulated with high dose estrogens to induce oocyte maturation for their egg recruitment and cryopreservation.

The Effect of Different Doses of Melatonin on in Vitro Maturation of Human Follicular Fluid-Derived Oocyte-Like Cells

“…The lack of SCP3 expression in the cells was observed, which probably indicated the immaturity of these cells (Virant-Klun et al, 2008). Researchers also showed, by dividing OLCs into groups featuring large or small cells that SCP3 expressed only in large cells (Silvestris et al, 2019). The results of the present study also showed higher levels of expression of this gene in the second week in the group treated with melatonin 10 -7 M, which was a significant increase compared to the first week and controls.…”

Germinal ovarian tumors in reproductive age women

“…[ 13 , 42 ] Similarly, the literature reports that AMH dosage and a pre-treatment fertility evaluation can help in the identification of patients with deficient ovarian reserve and who could benefit from a fertility preservation technique. [ 43 ] In this study, there was a very small percentage of pregnancy failure: 1 had SAB and 1 had IVP; these percentages are typically reported in a general population [ 44 ] ; therefore, it is difficult to demonstrate a relationship. [ 45 ] The literature on the possible dangerous effects of cancer treatments on pregnancy did not show an increased risk of genetic or other defects in births of women previously receiving antineoplastic treatment.…”

Role of Stem Cells in the Ovarian Tissue Cryopreservation and Transplantation for Fertility Preservation

“…The fertilization of stem cell-derived oocytes provides a new direction in the field of artificial reproductive techniques, which may be applied in the near future. Stem cells may be implanted in the patient's ovary or cultured into oocytes for in vitro fertilization [33][34][35].…”

“…Furthermore, the epigenetic status of embryogenesis in postnatal mammalian gonads needs to be investigated [38]. With more research, the isolation of ovarian stem cells might become useful to increase the outcomes of ovarian tissue cryopreservation and transplantation [35,39,40].…”