Postnatal oogenesis in humans: a review of recent findings

Irma Virant-Klun Department of Obstetrics and Gynaecology, University Medical Center Ljubljana, Ljubljana, Slovenia Abstract: In spite of generally accepted dogma that the total number of follicles and oocytes is established in human ovaries during the fetal period of life rather than forming de nov...

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Main Author: Virant-Klun I
Format: Article
Language:English
Published: Dove Medical Press 2015-03-01
Series:Stem Cells and Cloning: Advances and Applications
Online Access:http://www.dovepress.com/postnatal-oogenesis-in-humans-a-review-of-recent-findings-peer-reviewed-article-SCCAA
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author Virant-Klun I
author_facet Virant-Klun I
author_sort Virant-Klun I
collection DOAJ
description Irma Virant-Klun Department of Obstetrics and Gynaecology, University Medical Center Ljubljana, Ljubljana, Slovenia Abstract: In spite of generally accepted dogma that the total number of follicles and oocytes is established in human ovaries during the fetal period of life rather than forming de novo in adult ovaries, some new evidence in the field challenges this understanding. Several studies have shown that different populations of stem cells, such as germinal stem cells and small round stem cells with diameters of 2 to 4 µm, that resembled very small embryonic-like stem cells and expressed several genes related to primordial germ cells, pluripotency, and germinal lineage are present in adult human ovaries and originate in ovarian surface epithelium. These small stem cells were pushed into the germinal direction of development and formed primitive oocyte-like cells in vitro. Moreover, oocyte-like cells were also formed in vitro from embryonic stem cells and induced pluripotent stem cells. This indicates that postnatal oogenesis is not excluded. It is further supported by the occurrence of mesenchymal stem cells that can restore the function of sterilized ovaries and lead to the formation of new follicles and oocytes in animal models. Both oogenesis in vitro and transplantation of stem cell-derived “oocytes” into the ovarian niche to direct their natural maturation represent a big challenge for reproductive biomedicine in the treatment of female infertility in the future and needs to be explored and interpreted with caution, but it is still very important for clinical practice in the field of reproductive medicine. Keywords: human, follicle, oocyte, stem cells
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spelling doaj.art-80664dfae205497d969915936a6ba1002022-12-21T17:16:48ZengDove Medical PressStem Cells and Cloning: Advances and Applications1178-69572015-03-012015default496020943Postnatal oogenesis in humans: a review of recent findingsVirant-Klun IIrma Virant-Klun Department of Obstetrics and Gynaecology, University Medical Center Ljubljana, Ljubljana, Slovenia Abstract: In spite of generally accepted dogma that the total number of follicles and oocytes is established in human ovaries during the fetal period of life rather than forming de novo in adult ovaries, some new evidence in the field challenges this understanding. Several studies have shown that different populations of stem cells, such as germinal stem cells and small round stem cells with diameters of 2 to 4 µm, that resembled very small embryonic-like stem cells and expressed several genes related to primordial germ cells, pluripotency, and germinal lineage are present in adult human ovaries and originate in ovarian surface epithelium. These small stem cells were pushed into the germinal direction of development and formed primitive oocyte-like cells in vitro. Moreover, oocyte-like cells were also formed in vitro from embryonic stem cells and induced pluripotent stem cells. This indicates that postnatal oogenesis is not excluded. It is further supported by the occurrence of mesenchymal stem cells that can restore the function of sterilized ovaries and lead to the formation of new follicles and oocytes in animal models. Both oogenesis in vitro and transplantation of stem cell-derived “oocytes” into the ovarian niche to direct their natural maturation represent a big challenge for reproductive biomedicine in the treatment of female infertility in the future and needs to be explored and interpreted with caution, but it is still very important for clinical practice in the field of reproductive medicine. Keywords: human, follicle, oocyte, stem cellshttp://www.dovepress.com/postnatal-oogenesis-in-humans-a-review-of-recent-findings-peer-reviewed-article-SCCAA
spellingShingle Virant-Klun I
Postnatal oogenesis in humans: a review of recent findings
Stem Cells and Cloning: Advances and Applications
title Postnatal oogenesis in humans: a review of recent findings
title_full Postnatal oogenesis in humans: a review of recent findings
title_fullStr Postnatal oogenesis in humans: a review of recent findings
title_full_unstemmed Postnatal oogenesis in humans: a review of recent findings
title_short Postnatal oogenesis in humans: a review of recent findings
title_sort postnatal oogenesis in humans a review of recent findings
url http://www.dovepress.com/postnatal-oogenesis-in-humans-a-review-of-recent-findings-peer-reviewed-article-SCCAA
work_keys_str_mv AT virantkluni postnataloogenesisinhumansareviewofrecentfindings