115-year-old woman’s body sheds light on human longevity

The body of a 115-year-old woman may have provided the clues researchers need to determine why the body dies of old age.

According to Dr. Henne Holstege of VU University Medical Center in the Netherlands and her team of researchers, stem cell exhaustion may be the reason why the body can’t live indefinitely.

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This discovery was made possible by the death of 115-year-old healthy woman who donated her body to the purposes of science. She was the oldest person to ever have done so, and her gift has not only shed light on why the body eventually ages, but also on the number of cell mutations a healthy individual can live with into old age.

Holstege and her team discovered that, at the time of death, the elderly woman had more than 400 genetic mutations in her bloodstream, a finding that suggests most cell abnormalities are harmless to individuals over a lifetime. Previously blood mutations were only studied in cancer patients and those with chronic disease; however, this finding indicates that most likely everyone experiences massive amounts of cellular abnormalities regardless of health.

Only a select few cause the degenerative diseases associated with old age.

The women who donated her body did not have any symptoms of hematological illnesses, the researchers indicated, and added that an autopsy showed she “did not suffer from vascular or dementia-related pathology.”

What they did find was that the woman had more than 400 somatic mutations – those that are not passed on to offspring and do not lead to disease – in the white blood cells that were not found in her brain. Holstege explained to MNT that cells within the brain were not taken into account because those white blood cells rarely experience cell division after an individual’s birth.

It is decades of cell division that causes mutations, as every time a stem cell divides within the bone marrow to create a new blood cell it carries with it a risk for genetic mutation.

For the healthy donor, the mutations found in the research were mostly in non-coding regions of the genome that have not previously been linked with disease, but they were in “mutation-prone” areas. It was the second finding in regards to stem cells, however, that surprised researchers the most.

“To our great surprise we found that, at the time of her death, the peripheral blood was derived from only two active hematopoietic stem cells (in contrast to an estimated 1,300 simultaneously active stem cells), which were related to each other,” said Holstege.

What this suggests is that if a person can live into old age without any complicating health factors they will eventually hit a point (for the donor woman it was 115 years) where stem cells have completely exhausted themselves and are no longer able to keep dividing. This stem cell exhaustion could very well be the root cause of death due to old age.

What the team could not say was if outside factors could influence stem cell longevity or what the average age for complete stem cell death might be. In order to answer these questions, more research?and willing donors?are needed in the field of study.

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