Suppressing Brain Immune Cells Might Prevent or Delay the Onset of Dementia

A mouse study in the Journal of Experimental Medicine suggests the suppression of brain immune cells might prevent or delay the onset of dementia in humans, reports News-Medical . Earlier research indicated that although microglia limit the development of a harmful form of the tau protein, the formation of tau tangles in the brain as dementia progresses could cause the cells' attempts to destroy them to damage nearby neurons and worsen neurodegeneration. The researchers studied genetically modified mice that carry a mutant form of human tau that easily aggregates, feeding six-month-old mice either a compound to deplete microglia in their brains or a placebo for three months. The continued presence of microglia ensured that the brains of mice with tau tangles and the high-risk genetic variant APOE4 were severely shrunken and damaged by 9.5 months. However, mice with suppressed microglia appeared normal and healthy, with harmful forms of tau less present in their brains. Moreover, mice with microglia and mutant human tau but no APOE exhibited minimal brain damage and fewer signs of damaging tau tangles.