Scientists have found brain cells thought to control ageing, and were successfully able to reverse the process of getting older when replacing these old cells with new cells.
The team located a group of specialised stem cells in the hypothalamus that govern how fast the human body ages over time, and could be used to warn off age-related diseases and extend human lifespan.
The hypothalamus was always known to regulate important bodily functions including growth, development, reproduction and metabolism.
But a 2013 paper from the same team at Albert Einstein College of Medicine, New York, confirmed that the hypothalamus also played a role in ageing. Although they were not able to pinpoint exactly what was causing this at the time.
Their most recent work has been able to make this next step and identify the tiny population of adult neural stem cells, previously known to be responsible for forming new brain neurons.
They were able to confirm these cells, which regulate gene expression by releasing microRNA molecules into the cerebrospinal fluid, are responsible for ageing by looking at their effects on mice over a period of time.
As the number of stem cells began to diminish when the mice reached about 10 months, which is several months before the usual signs of aging start appearing, and by old age (about two years in mice) most of those cells were gone.
Dongsheng Cai, senior author, said: “Our research shows that the number of hypothalamic neural stem cells naturally declines over the life of the animal, and this decline accelerates aging.”
And in order to work out if they were causing ageing or just associated with ageing they disrupted the cells in middle-age mice, and Cai, said: “This disruption greatly accelerated aging compared with control mice, and those animals with disrupted stem cells died earlier than normal.”
This lead to questions about whether injecting new stem cells could slow or reverse ageing, and it did.
“We found that the effects of this loss are not irreversible. By replenishing these stem cells or the molecules they produce, it’s possible to slow and even reverse various aspects of aging throughout the body,” said Cai.
The researchers are now trying to identify the particular populations of microRNAs and perhaps other factors secreted by these stem cells that are responsible for these anti-aging effects.