Study finds maternal cells persist in human brain throughout life
A new preprint study found that cells originating from mothers are present in human brains in 70% of epilepsy patients studied, spanning multiple brain regions and persisting into advanced age. The phenomenon, called microchimerism, arises from the bi-directional exchange of cells between mother and fetus during pregnancy. The findings challenge conventional definitions of biological 'self' and may have broad implications for understanding neurological health and disease.
Researchers studying surgically resected brain tissue from epilepsy patients found maternal microchimerism — the presence of a small number of genetically distinct maternal cells — in 70% of subjects, often at notable quantities across temporal, frontal, parietal, and hippocampal regions. Using polymorphism-specific quantitative PCR to target maternal genetic markers, and a single-nucleus RNA profiling tool called cellector for demultiplexing rare allogeneic cells, the team identified maternal cells integrated across major neural and glial populations. Analysis of publicly available single-nucleus RNA sequencing datasets from neurotypical brains, spanning gestation to late adulthood, further confirmed that maternal microchimerism is widespread and long-lasting. These maternal cells appeared to preferentially adopt identities resembling L2/3 intratelencephalic neurons or microglial/macrophage-like cells. The authors argue that the prevalence, diversity, and persistence of this naturally acquired microchimerism invites a fundamental reconsideration of what constitutes biological 'self' in the human brain.
What's missing
As a preprint, this study has not yet undergone formal peer review. The primary patient cohort consisted of epilepsy patients, who may not be representative of the general population, and the authors do not fully address whether the epileptic condition itself influenced the prevalence or distribution of microchimerism. The functional consequences — whether these maternal cells are beneficial, harmful, or neutral — remain unknown. The mechanisms by which maternal cells cross the blood-brain barrier and integrate into specific neural lineages are not established.
What different sources said
- bioRxivCenter
Microchimerism in the human brain, quantitative assessment and single nuclei profiling establish cell types and diversity
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