Menopause has long been considered a terminal time for the female reproductive system, when the ovaries stop releasing eggs and likely brings this period to an end.
But this simplified picture of ovarian retirement simply doesn’t hold water, as researchers take a closer look at what happens to these organs after menopause.
“In the ovary, we reach a point of no return in fertility where it no longer produces eggs, and I would venture to say that most people assume that those ovaries just sit there, doing nothing, like the appendix,” says reproductive biologist Francesca Duncan of Northwestern University.
“The ovary is not just a reproductive organ,” explains proteomics expert Birgit Schilling from the Buck Institute.
“It really influences how a person ages because it speaks to all these other organs, like the brain, but also the bones, and women after menopause often experience a lot of bone problems. So we think there’s a connection between all these organs.”
Schilling and Duncan led a new study published today in the scientific journal Aging cell.
Their results suggest that for the ovary, menopause is much more like a career change than a retirement.
))>The researchers used mass spectrometry to determine which proteins were active in the healthy ovaries of 28 postmenopausal women, depending on the age of the tissue donor: 50 to 59 years, 60 to 69 years, and 70 years and older.
These women had their ovaries surgically removed for a variety of reasons, but none of the ovaries included in the study showed signs of disease.
The results mirror what Duncan found in mouse ovaries in a study published earlier this year: The protein profiles produced by ovarian tissue gradually change with age. In human ovaries, a set of seventeen proteins actually characterizes this change.
Ovaries in the 50-59 age group contained more proteins related to the regulation of RNA and DNA and the maintenance of tissue and cell structure. In contrast, the ovaries of the 70 and older group contained more proteins involved in lipid metabolism, innate immunity and inflammation.
If the ovaries were “inert” after their reproductive years, this would not be the case.
“I predicted that if we took a 50-year-old ovary, a 60-year-old ovary, a 70-year-old ovary, an 80-year-old ovary, they would all look exactly the same, have no eggs, and be basically non-functional,” Duncan says.
“The fact that we are seeing this in all species gives us confidence that this is not just a random event, but that something truly significant is happening in biology.”
Life expectancy is generally getting longer than ever, which means there are now many more menopausal people wandering around, whose bodies we don’t yet fully understand.
The risk of ovarian cancer is much higher after menopause, and the new study reveals why that might be the case.
Age-related changes in ovarian tissue and immune cells at the protein level create an ideal environment for tumors by loading the extracellular matrix with collagen.
The ovarian tissue samples in this study were, of course, free of tumors, but proteins previously linked to ovarian cancer were abundant, most notably in the ovaries of women in their 60s.
“It’s not that all postmenopausal women get ovarian cancer, but we know that this fibrous inflammatory environment is certainly one in which cancer cells prefer to concentrate,” Duncan says.
“All of this is consistent with the idea that ovarian aging is a potential third impact of ovarian cancer, with the first impact being genetic and the second impact being environmental. So can we therapeutically target the aging ovary to reduce the risk of ovarian cancer, or can we develop new biomarkers for ovarian cancer?”
With a first “road map” for ovarian aging now established, researchers can begin to delve deeper into these more nuanced questions.
These findings could have important implications for health care during the post-reproductive years and in people who have had their ovaries removed.
The research was published in Aging cell.
This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. Although we are proud of our process, we are only human. If you spot an error, please let us know.
Gn Health
