In a glimpse of what could become a future Black Mirror episode, scientists have hooked the circulatory systems of old mice to young mice, and found that it slows the aging process in the older animals and increases their lifespan by up to 10%.
In recent years studies have increasingly shown that giving older mice blood transfusions from young mice results in a range of health benefits, including improved neurological function, slowing progression of diseases like Alzheimer’s, and increasing lifespan. But if that’s just from the occasional hit of young blood, what could more sustained doses do?
For the new study, led by Duke Health, scientists surgically connected the circulatory systems of old and young mice. The process is called heterochronic parabiosis, and it’s previously been used to study whether Alzheimer’s originates outside of the brain.
The researchers connected young mice of four months old, and older mice aged two years, then studied their health over 12 weeks – equivalent to about 10% of a mouse’s lifespan. In human terms, that would be like pairing a 50 year old with an 18 year old for around eight years, the team said. The mice were then separated, and followed for a further two months to see how long the effects lasted.
And sure enough, the older mice appeared healthier and lived longer than control mice, although the increase was modest – only an average of 6 to 9%. The epigenetic age of their blood and liver tissue was drastically reduced, and their gene expression took on anti-aging patterns similar to those seen during processes like caloric restriction.
During the two-month follow-up, the scientists found that some of the benefits granted to the old mice lasted throughout the study period. The young mice, meanwhile, were quickly able to clear out the molecular damage they’d sustained from their older peers.
“When the mice develop a joint circulatory system, the damage from the old mice goes to the young mice and increases their biological age,” said Vadim Gladyshev, co-lead author of the study. “But in the case of the old mouse, this process dilutes their damage. After detachment, the damage transferred to the young mice from the old can be cleared over time, whereas in the old mice, this damage is diluted permanently.”
While it’s obviously not practical to connect the circulatory systems of old and young humans (we hope), the team says that future work could identify the specific molecules that bestow benefits, with the hope of isolating those to develop new anti-aging therapies.
“The elements that are driving this are what’s important, and they are not yet known,” said James White, senior author of the study. “Are they proteins or metabolites? Is it new cells that the young mouse is providing, or does the young mouse simply buffer the old, pro-aging blood? This is what we hope to learn next.”
The research was published in the journal Nature Aging.
Sources: Duke Health, Harvard
