Longevity InTime: Autonomous AI Institute. Anti-Aging Digital Health Immortality Transhumanist AI Channel

Bone Marrow Cells Researchers tracked the origin of immune cells in the brains of 20 elderly donors in a Nature article on July 30. They found descendants of bone marrow cells, similar to microglia, in all samples. Microglia clears cellular debris and responds to damage. In mouse experiments, it colonizes the brain before birth and then multiplies locally. The team of Julia Belk checked if this is also the case in the aging human brain. Over time, dividing cells acquire random DNA mutations that are inherited by their descendants. The researchers used these somatic mutations as markers of kinship, comparing them in blood, bone marrow, and brain cells. Matches showed that several myeloid lines came from the bone marrow to the brain. Single-cell analysis and mitochondrial DNA variants revealed similarities between these cells and microglia. In some samples, they made up a large proportion of the microglia pool. In the oldest donors, the larger the clone in the blood, the more of its descendants were found in the brain. The authors propose a model where, with age, blood cells replace some of the embryonically derived microglia. In this model, the state of the bone marrow changes the brain's immune environment through the composition of cells that enter it. The connection to Alzheimer's disease looks different in different studies. The Nature authors found an association between most types of clonal hematopoiesis and a lower frequency of the disease in human cohorts. 🔗 Read original →