Scientists recently analyzed the blood of a woman who lived a healthy life up to the age of 115. They were surprised to discover that 64% of her blood cells were descended from only two different blood stem cells. Is this the key to longevity?

There’s reason to be cautious with these conclusions: 36% of this patient’s blood came from a much larger, diverse group of blood stem cells, so other stem cells were still alive and functioning. We also don’t know how the blood stem cell activity changes over time. Perhaps these two cells were only temporarily dominant, with other cells resting, waiting to take over. And finally, at the age of 115, this woman did not die from a lack of cell division due to loss of telomeres, but rather from too much cell division- she got a gastric cancer that eventually impaired organ function.

In addition to shortened chromosomes, about 600 mutations had also accumulated in her blood stem cells. These mutations were most likely harmless, and researchers concluded that accumulation of mutations is a normal occurrence during ageing. Of course, not all mutations are harmless, and the more frequently cells divide, the greater the chance that a harmful mutation will occur.

Although researchers found valuable information about normal ageing processes, they still don’t understand why this particular woman lived to be 115. She did have some unique variants of genes whose job is to help prevent mutations from occurring during DNA replication, but it’s not clear whether they played a role in extending her lifespan.

A special thanks to Harvard PhD students Jamie Lahvic and Katherine Rogers for sharing their expertise.

Managing editor, Nicole Espy.

Further reading from SITN:

Flash Special Edition: Stem Cells

“Never an Easy Answer: The Ethics of Stem Cells”

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