Scientists 'rejuvenate' the aged eggs of mice -- is it possible in people?

[Bayard]

In an experiment, scientists showed that they can seemingly reverse aspects of aging in mouse egg cells, which are similar in structure to the human cells above. (Image credit: Ed Reschke via Getty Images)

Aging egg cells can be rejuvenated when placed inside young follicles, a new study of mouse cells suggests. The study could serve as proof-of-concept for future fertility treatments aimed at reversing aging in human egg cells — but much more research is needed to translate these findings to people. As immature egg cells, called oocytes get older, they begin having problems with cell division. This can result in aneuploidy, in which the chromosomes in the early oocyte don't separate correctly, resulting in extra or missing chromosomes. This causes higher rates of miscarriage.

People can now freeze their oocytes to help preserve their ability to have children. However, there is currently no method of reversing the effects of aging on older oocytes. In a paper published Monday (Sept. 7) in the journal Nature Aging, scientists at the National University of Singapore demonstrated a new way to model the maturing oocyte in the lab. Through that work, they found that oocytes from older mice that were grown with young mouse cells became rejuvenated, and this improved the rates of live births when the eggs were implanted back into mice.

Senior study author Rong Li, director of the Mechanobiology Institute at the University of Singapore, and her team have been interested in cellular aging for a long time. They started studying the oocyte when they realized that the ovary is the fastest aging organ in the body. "So when someone is only 40 years of age, everything else is very young and healthy, but the ovary is very old, [limiting] reproductive ability," Li told Live Science. This also makes ovaries a great model for the study of aging, in general.

As an oocyte matures, it undergoes multiple rounds of cell division before it's eventually released from the ovary during ovulation. This complex and energetic process is made possible by a follicle that surrounds the maturing oocyte and provides the energy and nutrients needed through thin filaments called tranzonal projections, or TZPs. Without these lifelines to the follicle, an oocyte cannot mature properly.


https://www.livescience.com/health/fertility-pregnancy-birth/scientists-rejuvenate-the-aged-eggs-of-mice-is-it-possible-in-people