Aging Blood: How Stem⁤ Cell Clones Impact Blood Production

Updated June 17, 2025
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As people age, ⁣the landscape of their blood system undergoes a critically important transformation. Research ⁤published in ⁣ Nature reveals that a select few blood stem cell clones begin to outcompete others, gradually seizing control of blood production. This⁤ process, observed in both humans and mice, results in a shrinking blood stem cell reservoir dominated by these aggressive clones.

The study indicates that these changes are ofen⁤ detectable around age 50, becoming nearly global by⁤ age 60. Scientists believe this decline in clone diversity could be a key factor in “inflammaging,”‍ the chronic inflammation associated with aging that increases vulnerability⁢ to various diseases. The consistency of this pattern across species suggests it’s a fundamental aspect⁣ of how blood ages.

Lars Velten, phd, group leader at the center for Genomic Regulation (CRG) in Barcelona, ⁣said the dominance of certain blood stem cell clones reduces the blood system’s resilience.”Our blood stem cells compete for survival,” Velten said. “in youth, this competition produces a rich, diverse ecosystem while in old age, some drop out entirely… This⁢ reduces ⁣diversity, wich is bad for the blood system’s resilience.”

To unravel this process, researchers developed a novel technique⁣ called EPI-Clone, which analyzes methylation marks on ⁢DNA⁣ to trace the lineage of blood stem cells. These marks ⁢act as natural “barcodes,” passed down from parent cells to daughter cells, allowing scientists to reconstruct the ⁤history of blood production.Alejo Rodriguez-Fraticelli, PhD, group ⁤leader at IRB‍ Barcelona, ⁢noted that EPI-Clone allows them to construct an “epigenetic family tree” by reading information written directly into the⁢ DNA of each cell.

The study revealed that in younger blood, a diverse ‍pool of stem cells contributes to the production of blood cells and platelets. However, in older mice, up to 70% of blood stem cells originated from just a few dozen clones, compared to about ⁢50% in younger mice. A similar trend was observed in humans, with the shift becoming ⁢more pronounced after age 60, ⁢according to Indranil Singh, a PhD student at IRB⁢ Barcelona.

Researchers also⁢ found that some dominant clones carried mutations linked to clonal haematopoiesis (CH),a condition associated with increased risk of heart ‍disease,stroke,and⁤ leukemia.Though, many⁢ dominant clones had no known mutations, suggesting that clonal expansion ⁢is a general feature of aging blood, not ⁤solely a sign of cancer risk.

What’s next

These findings ⁢could pave the‍ way for early detection and prevention strategies for age-related diseases. Clinicians may one day be able to assess clonal behavior to monitor the aging of a person’s blood stem cell pool, potentially flagging individuals for preventive care years before symptoms develop. The research was funded by the European Haematology Association and the⁤ Spanish Association Against Cancer (AECC).