Stem cell discovery could preserve women's fertilityUnlimited number of eggs
Scientists have discovered a type of stem cell in women's ovaries which can produce what appear to be normal egg cells or oocytes, according to a new study.
The discovery raises the possibility of creating a bank of frozen 'oocyte-producing stem cells' to treat women left infertile through medical treatment or disease, or who may just want to delay having a baby.
The study findings challenge the long-held theory that women are born with a finite number of eggs that decline in number throughout life until the menopause.
Previous research by the same team at Massachusetts General Hospital (MGH) suggested that adult female mice have oocyte-producing stem cells (OSCs) which can grow into mature OSCs that can be fertilised and develop into healthy offspring.
But in this study, the researchers identified a unique protein - known as DDX4 - on the surface of human OSCs which allowed them to isolate a pure population of the cells from adult human ovaries.
The OSCs spontaneously formed cells with the same physical appearance and genetic characteristics of immature eggs or oocytes in the laboratory.
The researchers injected the OSCs into human ovarian tissue that had been grafted into mice. After seven to 14 days, the OSCs had matured and generated new human oocytes.
"The primary objective of the current study was to prove that oocyte-producing stem cells do in fact exist in the ovaries of women during reproductive life, which we feel this study demonstrates very clearly," said study leader Dr Jonathan Tilly, director of the Vincent Center for Reproductive Biology at MGH.
"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."
Dr Allan Pacey, a fertility expert at the University of Sheffield, told the BBC: "This is a nice study which shows quite convincingly that women's ovaries contain stem cells that can divide and make eggs.
"Not only does this re-write the rule book, it opens up a number of exciting possibilities foe preserving the fertility of women undergoing treatment for cancer, or just maybe for women who are suffering infertility by extracting these cells and making her new eggs in the lab."
The study is published in the journal Nature.
This article was published on Mon 27 February 2012
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