Heterochronic Parabiosis in Mice Fails to Extend Lifespan in the Older Animal

As practiced in the laboratory, heterochronic parabiosis is the surgical joining of the circulatory systems of an old and young mouse. The older mouse shows signs of rejuvenation, the younger mouse shows signs of accelerated aging. This has led to a great deal of debate and further research into mechanisms; the present weight of evidence favors the improvements in the old mouse to result from a dilution of harmful factors, such as damaged albumin, in the aged bloodstream, rather than by any provision of pro-regenerative factors carried in your blood but not in old blood. Researchers here show that heterochronic parabiosis actually fails to extend life span in the older mice, an interesting addition to the present body of evidence.

A new study in which young and old mice were surgically joined such that they shared blood circulation for three months showed that the old mice did not significantly benefit in terms of lifespan. In contrast, the young mice that were exposed to blood from old animals had significantly decreased lifespan compared to mice that shared blood with other young mice. Heterochronic parabiosis is a research tool used to assess the effect of organs and of blood-borne factors on young and old animals. Less controlled than direct blood exchange, parabiosis is a model of blood sharing between two surgically connected animals.

Researchers used heterochronic parabiosis between young and old mice and the isochronic controls for three months. They then disconnected the animals and studied the effects of being joined on the blood plasma and animal lifespan. "The most robust and interesting result of this study is the fact of a significant decrease in the lifespan of young mice from heterochronic parabiotic pairs. This data supports our assumption that old blood contains factors capable of inducing aging in young animals. Finding and selective suppression of aging factor production in the organism could be the key research field for life extension."

Link: https://home.liebertpub.com/news/can-exposure-to-young-blood-increase-lifespan/4941


Aspiring Blood Boys should seek alternative employment. But I am not writing off parabiosis because of one study out of Ukraine.

Posted by: JohnD at August 11th, 2022 3:54 PM

Were there doing it again with genetically different mice?

I wonder why they stubbornly refuse to do the experiment with genetically identical mice (young clones of old ones).

Posted by: Sanchez at August 11th, 2022 6:23 PM

It seems parabiosis studies will also suffer from reproducibility issues. I would expect the older individuals to benefit at least from having an extra sets of kidney, stomach and liver.

Posted by: Cuberat at August 12th, 2022 9:41 AM

The good news is that it does not prolong life. It means, among other things, that they conducted the experiment honestly.

Posted by: Richard Adamec at August 15th, 2022 10:29 AM

Discouraging, but it's still just one mouse study. IMO, I'd still be surprised if there wasn't any positive effect on longevity from heterochronic parabiosis found eventually (or at least healthspan), given that it has been shown to have a positive affect on factors already known to impact health (stem cells activity, inflammation, etc).

Posted by: K at August 17th, 2022 8:09 PM
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