Holy Hormones Honey! Well, I think the The Scientist is presenting ‘old’ science in this article. Don’t get me wrong – it is fascinating to understand the mechanisms of action as to why our eggs die as we age. However, what if women increased their nutritional intake to the brain so that the DNA repair mechanisms did not become less efficient. What if we slowed down our aging process all together. Think about it. Young women may really have to start thinking hard about this…because at the rate we are going with so many endocrine disruptors in our environment and the lack of nutrients in our diet – their DNA processes will be breaking down before they even start thinking about having children.
Why Women’s Eggs Don’t Last
As reproductive tissues age, DNA repair mechanisms become less efficient, causing genomic damage to accumulate
By Kate Yandell | February 13, 2013
A woman’s eggs decline in quality and quantity as she ages, at least in part because an important DNA repair pathway becomes impaired, according to a paper published today (February 13) in Science Translational Medicine.
The pathway, which includes proteins encoded by the well-known BRCA genes, is supposed to repair double-strand breaks in DNA. But as women get older, the study found, repair mechanisms lose efficiency and reproductive cells accumulate damaged genes and often commit suicide.
“I think we have found a general theory of reproductive aging,” said coauthor Kutluk Oktay, a fertility specialist at New York Medical College and the Institute for Reproductive Medicine and Fertility Preservation.
“They are tying together something that has been perplexing and vexing, which is what happens to women’s eggs as they age,” said David Keefe, a New York University Langone Medical Center fertility doctor who wrote a commentary on the paper.
While women are born with 1 million oocytes, only about 500 turn into full-fledged eggs over their lifetime. By the time women reach their early 50s, the remaining oocytes have almost completely degraded. Why the oocytes degrade so rapidly in comparison to other body tissues was a mystery.
Oktay’s team first tested mouse and human oocytes for double-strand breaks and found that the damage increased significantly with age. They also looked at expression of several repair proteins in the cells. Expression of BRCA1 and a handful of other repair genes decreased with age. The results implied that dysfunction in DNA repair may lead to genomic damage seen in aging oocytes.
Indeed, when the researchers down-regulated repair genes using RNA interference and exposed oocytes to hydrogen peroxide, they saw higher rates of double-strand breaks. And when they over-expressed BRCA1 in old mouse oocytes, the cells were more likely to survive hydrogen peroxide exposure—about as well as the oocytes of young mice.