How do old cells in adult humans give rise to the youthful cells found in infants? New research suggests they reset to their lowest biological age in early embryonic development, with potential ramifications for longevity science.
For a long time, it was assumed that germline cells—those that form eggs and sperm and pass a parent’s genetic information on to their children—were essentially ageless. But how this could be was never clear and more recent research had shown that germline cells do accumulate the signs of aging.
This led to the conclusion that there must be some kind of rejuvenation event that allows the offspring’s cells to start with a clean slate. But when and how this occurs was a mystery.
Now a team from Harvard has shown that the age of mouse embryo cells resets about a week into development, representing the “ground zero” of aging. The finding not only provides insight into the fundamental dynamics of aging, but also suggests we might mimic the process in adult cells to rejuvenate aging tissues.
June 28, 2021
Harvard Scientists Pinpoint ‘Ground Zero’ of Aging in Mouse Embryo Study
[I had often wondered about this. If old age is caused, primarily, by the shortening of telomeres, then how do embryos get normal length telomeres from non-infant parents? I figured that someone must know, it’s such an obvious question. And the obvious follow up question of, “Can we replicate this restoration of telomeres in an organism?” Must have an answer similar to, “No, it only happens during the union of a single sperm and egg.”
That these were unanswered questions has incredible consequences now that answers are being discovered.—Joe]