Researchers at the Massachusetts General Hospital (MGH) have isolated egg producing stem cells from human ovarian tissues.
Scientists at the Vincent Center for Reproductive Biology, MGH used a special fluorescence-activated cell sorting protocol in mice models to grow new eggs from isolated stem cells.
The new study is seen as a precursor to solving fertility issues in women of reproductive ages. If made viable, the study could benefit young women undergoing cancer therapy and older women who have to resort to egg donors.
The current breakthrough challenges the widely-accepted notion that while men generate sperms throughout life, women are born with a fixed supply of eggs that deplete with age and are finally exhausted at menopause.
The current research, published in the March issue of Nature Medicine is a follow-up on an earlier landmark 2004 Nature paper suggesting that female mammals have the capability of producing egg cells throughout their adult reproductive stages.
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"The discovery of oocyte precursor cells in adult human ovaries, coupled with the fact that these cells share the same characteristic features of their mouse counterparts that produce fully functional eggs, opens the door for development of unprecedented technologies to overcome infertility in women and perhaps even delay the timing of ovarian failure," said Jonathan Tilly, lead researcher and Director for Reproductive Biology at the MGH Vincent Department of Obstetrics and Gynecology.
To examine their arguments, the researchers injected green fluorescent protein (GFP)-labeled mouse oocyte-producing stem cells (OSCs) into the ovaries of normal adult mice. Several months later, the recipient mouse ovaries showed the presence of follicles containing oocytes (immature egg cells) with and without the marker protein. Similar GFP-labeled and unlabeled oocytes were observed in cell clusters flushed from the animals' oviducts after induced ovulation.
The GFP-labeled mouse eggs were fertilized in the lab to produce embryos that went on to the hatching blastocyst cell reproductive stages, indicating potential for normal egg cell development.
According to Tilly, "In this paper we provide the three key pieces of evidence requested by those who have been skeptical of our previous work."We developed and extensively validated a cell-sorting protocol to reliably purify OSCs from adult mammalian ovaries, proving once again that these very special cells exist. We tested the function of mouse oocytes produced by these OSCs and showed that they can be fertilized to produce healthy embryos. And we identified and characterized an equivalent population of oocyte-producing stem cells isolated from adult human ovaries", he added.
See more here:
Ovarian Stem Cells Holds Promise for Infertile Women: Study