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Bone marrow cells in brain linked to Alzheimer

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2026-09-03 07:39 UTC → 2026-09-22 08:19 UTC · added ~~removed~~

Researchers at Stanford University have reported that immune cells originating in the bone marrow can enter the human brain and resemble microglia. An initial pre‑print described the discovery in brain tissue from older adults and noted that clonal hematopoiesis—a condition where blood cells derive from a single stem cell—was associated with a reduced risk of Alzheimer disease. A follow‑up report, published in Nature, expanded the findings, showing that aging is accompanied by a substantial influx of these bone‑marrow‑derived immune cells. Analysis of large genetic cohorts confirmed that individuals with specific clonal hematopoiesis mutations were less likely to develop Alzheimer’s, suggesting a possible protective role. ~~The later article also placed the results in a broader context, linking systemic health conditions to brain structure and function through advanced neuroimaging.~~ Building on this, ~~a study~~ research involving ~~researchers from~~ the University of California, San Diego, UC Irvine, and the New York Genome Center identified a significant shift in brain immune cell composition occurring around age 50. By analyzing hippocampal tissue, scientists observed that resident microglia are increasingly replaced by immune cells entering from the bloodstream. These incoming blood-borne cells carry more pronounced inflammatory signals, which may contribute to chronic inflammation linked to cognitive decline. This research suggests a degradation of cells maintaining the blood-brain barrier alongside broader changes in DNA and gene activity. Lead author Nathan Zemke noted that these findings could eventually lead to new approaches for treating Alzheimer's and other neurological diseases without needing to directly manipulate cells within the central nervous system, though he emphasized the study is in its early stages. Recent ~~findings published in Nature~~ studies have further clarified ~~this mechanism, utilizing~~ these mechanisms. Utilizing somatic mutations as natural markers to track cell origins in 20 elderly ~~individuals.~~ individuals, researchers confirmed that human brain immune cells can be replenished by cells born in the blood. Additionally, new findings published in Science indicate that human brain cells undergo significant changes starting around age 50 regarding genome regulation. In the hippocampus, microglia decrease sharply between ages 50 and 75, being replaced by cells with molecular characteristics linked to higher inflammation.

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