Stem cells in aged mammalian ovaries

ovary undergoes several changes after the menopause. The main characteristics of the post-menopausal ovary are a loss of follicles and several changes as a consequence of apoptotic processes. Signs of atrophy and fibrosis are evident. Primordial follicles are usually absent in postmenopause, whereas corpora atretica, hemorrhagica and albicantia, scar tissue, and simple follicular cysts are common. Ovarian surface epithelium during the embryonic and reproductive periods of life Ovarian surface epithelium (OSE) is an important structure of the human ovary and is involved in both reproductive function and ovarian tumor formation. Primordial germ cells (PGCs) in embryonic ovaries are of extraovarian origin, but those developing during the fetal period are derived from the OSE. PGCs in the fetal ovary express most, but not all of the markers associated with pluripotent cells [1] and can develop into pluripotent stem cells such as embryonic germ cells (EGCs) and embryonic carcinoma cells (ECCs). With the support of the immune system cells, secondary germ cells and primitive granulosa cells arise from the OSE stem cells in the fetal gonads. Additionally, human neonatal thecal stem cells have already been isolated, characterized, and differentiated in vitro and in vivo [2]. Because of its physiological role during the fetal period Commentary of life, the OSE layer has also been termed " germinal epithelium. " During the adult, reproductive period of life, OSE is mainly involved in the physiological process of ovulation. Ovulation induces cyclic rupture and regenerative repair of the ovarian coelomic epithelium. This process of repeated disruption and repair accompanied by the complex remodeling reflects a somatic stem/progenitor cell-mediated process in the mammalian ovaries; a label-retaining cell population in the coelomic epithelium of the adult mouse ovary has already been identified as possible somatic stem/progeni-tor cells [3]. The OSE layer gradually flattens, but is always present, even in menopausal females of advanced age [4]. Apoptotic and necrotic cells frequently appear within the OSE layer. It seems that human OSE stem cells retain the characteristics of embryonic stem cells. Based on previous experience [5], Virant-Klun and her coworkers [6,7] scraped the OSE in women with no naturally occurring oocytes and follicles: postmenopausal women and young women with premature ovarian failure (POF). Copyright: © Virant‐Klun and Skutella. This is an open‐access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are …