Differential Expression of Ovarian Superficial Epithelium Markers in Diminished Ovarian Reserve and Normal Women

In the last years, diminished ovarian reserve (DOR) is becoming a frequent pathology in the human reproductive system, which also has a major impact on quality of life and fertility of reproductive age women. However, DOR remains as a disease of unknown etiology. The aim of this study was to assess the differential expression levels of multipotent stem cell markers in the ovarian surface epithelium (OSE) of women with DOR and women with adequate ovarian reserve (AOR) that could be associated with the loss of ovarian functionality. Methods: The present study was performed by using ovary tissue samples from patients previously diagnosed as AOR and DOR according to the clomiphene citrate challenge test. The expression levels of multipotent stem cell and germline markers were analyzed by immunohistochemistry. Results: Our findings demonstrate that a small number of epithelial cells express the Oct4 stem cell marker and the specific germ line markers (Fragilis, Stella, and VASA) in the OSE of both AOR and DOR patients, but the number of immunostained cells were lower in the women with AOR than DOR individuals. On the other hand, the expression of SOX2 and Nanog stem cell markers was only observed in the OSE of DOR women but not in AOR patients. Conclusions: The overall results of this study show that there is a differential expression of stem cell markers in the OSE cells from DOR women as compared with AOR subjects, suggesting a possible compensatory mechanism for the generation of new multipotent cells to participate in the repair and/or renewal of the population of ovary cells in the OSE of DOR women.