A new study of the blood of one of the world’s oldest women, Hendrikje van Andel-Schipper, supports what we have hypothesized for a long time: Human beings run out of adult stem cells. This is the likely cause of death in the oldest old – supercentenarians whose healthy immune systems have prevented cancer and other age-related diseases. They die eventually because they have no stem cells left to replenish their tissues.
Somatic mutations found in the healthy blood compartment of a 115-yr-old woman demonstrate oligoclonal hematopoiesis
Genome Research, 2014 Apr 23. [Epub ahead of print] DOI: 10.1101/gr.162131.113
Henne Holstege, Wayne Pfeiffer,Daoud Sie, Marc Hulsman, Thomas J. Nicholas, Clarence C. Lee,Tristen Ross,Jue Lin, Mark A. Miller,Bauke Ylstra, Hanne Meijers-Heijboer, Martijn H. Brugman, Frank J.T. Staal,Gert Holstege, Marcel J.T. Reinders, Timothy T. Harkins, Samuel Levy, Erik A. Sistermans
Abstract
The somatic [body-cell, not blood-cell] mutation burden in healthy white blood cells [WBCs] is not well known. Based on deep whole-genome sequencing, we estimate that approximately 450 somatic mutations accumulated in the nonrepetitive genome within the healthy blood compartment of a 115-yr-old woman. The detected mutations appear to have been harmless passenger mutations: They were enriched in noncoding, AT-rich regions that are not evolutionarily conserved, and they were depleted for genomic elements where mutations might have favorable or adverse effects on cellular fitness, such as regions with actively transcribed genes.
The distribution of variant allele frequencies of these mutations suggests that the majority of the peripheral white blood cells were offspring of two related hematopoietic stem cell (HSC) clones. Moreover, telomere lengths of the WBCs were significantly shorter than telomere lengths from other tissues. Together, this suggests that the finite lifespan of HSCs, rather than somatic mutation effects, may lead to hematopoietic clonal evolution at extreme ages [meaning that mutations did not kill her, but so few stem cells left to replenish her immune system was the likely culprit].
© 2014 Holstege et al.; Published by Cold Spring Harbor Laboratory Press
Living to supercentenarian-hood is not the only way to run low on adult stem cells: Excessive weight, immune system burdens, disease, and emotional stress and some of the challenges that can deplete your stem cell reserve.
Thank you, Hendrikje, for keeping us on track. You have helped us understand that LivingTheCRWay strategies to slow aging and possibly reverse it, are on target:
- CR Way DNA HACR testing (Become a full member to see the tests to help determine if your lifestyle helps preserve your stem cell reserve
- A life extension strategy focusing stem cell replacement in a biological environment that allows them to prosper. (Become a Healthy Start member of LivingTheCRWay.com to access the Stem Cell forum)
It also puts all of us on notice to act fast. We need healthful stem cell replacement solutions now, and we need to make sure that immune system challenges are not unnecessarily depleting our stem cell populations.
Are you saving your stem cells for replacement use later? Join this discussion and tell us about it: Stem Cell Storage or enter your own post in the Stem Cell forum.
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