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No evidence for new eggs in adulthood

21 May 2007
Appeared in BioNews 408

Hopes aroused by a controversial study suggesting that women may be able to produce new egg cells have been seemingly dashed. The 2005 paper, published in the journal Cell by researchers at Massachusetts General Hospital, fleetingly gave hope to infertile women when it suggested that egg production may be restarted in sterile mice.

This work, however, was challenged last year in a Nature paper published by Harvard researchers, who could find no evidence of egg regeneration. And now a new study, published in the latest issue of the journal Developmental Biology, further entrenches this viewpoint.

Pioneering work by Solly Zuckerman in the 1950's showed that female mammals are born with all of their eggs, a viewpoint that remained unchallenged until reproductive endocrinologist Jonathan Tilly's work on mice 2004-5. His research seemed to provide evidence for 'ovarian stem cells' present in the mouse bone marrow, which had the ability to migrate and repopulate mice ovaries rendered infertile by chemotherapeutic agents, following a transplant.

The latest research, led by University of South Florida scientists Lin Liu and David Keefe looked at gene expression profiles (which reveal gene activity) in the ovaries of 12 women aged between 28 and 53. They found no evidence of any expression pattern signatures consistent with egg cell production and subsequent ovulation.

'Despite using the most sensitive methods available, we found no evidence of any egg stem cells in human ovaries, demonstrating that Dr Tilly's findings in mice do not apply to women', Dr Keefe said. 'Dr. Tilly likely was seeing non-egg cells which resemble eggs'.

Tilly countered in the most recent issue of Cell Cycle, 'It is disappointing to see arguments against the possibility of postnatal oogenesis [new egg cell production] in mammals still being drawn using solely an 'absence of evidence' approach'.

Some hope remains though, as the cells Tilly has visualised in mice may prove to be eggs, albeit immature non dividing ones, which could prove central to some form of future treatment.

Hopes Dashed: Women Don't Generate New Eggs
Yahoo Daily News |  15 May 2007
Study Debunks Theory That Fertility Can Be Restored
Medical News Today |  13 May 2007
30 July 2012 - by Professor Robin Lovell-Badge 
Earlier this year, a paper claimed to have found cells, called ovarian stem cells, in the adult ovaries of both mice and humans. These cells could apparently be grown in large numbers in the lab and could retain the ability to give rise to eggs. A new study finds no evidence for the existence of germline progenitors able to produce eggs in postnatal ovaries. Is a lack of evidence sufficient to win the argument?...
12 March 2012 - by Professor Robin Lovell-Badge 
I am all for challenging dogma, but to do so requires robust evidence and carefully drawn conclusions. In the case of Professor Jonathan Tilly's much-trumpeted study on stem cells in ovaries that can give rise to eggs, I feel that both were missing...
27 February 2012 - by Antony Starza-Allen 
Scientists in the USA have shown it may be possible to isolate egg-producing stem cells from women's ovaries....
16 June 2006 - by Dr Jess Buxton 
A new US study has cast serious doubt on controversial research that suggested bone marrow stem cells can produce new eggs in adult mice. Last year, a team based at Massachusetts General Hospital reported in the journal Cell that the eggs of mice rendered sterile could...
1 August 2005 - by BioNews 
Bone marrow stem cells can produce new eggs in adult mice, US researchers say. A team based at Massachusetts General Hospital has shown that the eggs of mice rendered sterile with a drug can regenerate within 24 hours, and that these germ cells originate from bone marrow. The findings, published...
8 May 2005 - by BioNews 
US researchers have managed to grow human eggs in the laboratory, using cells scraped from the surface of ovaries. The team, based at the University of Tennessee, Knoxville, say that the findings could lead to a new way of preserving female fertility, and also a potential new source of egg...
5 July 2004 - by BioNews 
The ovaries of adult mice contain egg-generating germ cells, scientists revealed at the European Society for Human Reproduction and Embryology's annual conference. The results have prompted hopes of a treatment for women with few eggs, such as those treated for cancer or nearing menopause. The discovery had been published in...
15 March 2004 - by BioNews 
Mammals may continue to produce new eggs throughout their lives, a study carried out on mice suggests. The findings challenge the long-held belief that female humans, mice and other mammals are born with a finite supply of eggs, which lasts until the menopause. A team of researchers at the Massachusetts...
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