Nathan Zemke, Ph.D.

New research suggests that around age 50, protective immune cells in the brain start to decline and are increasingly replaced by inflammatory cells entering from the bloodstream. Researchers believe this shift contributes to neuroinflammation, which increases the risk of neurodegenerative diseases such as dementia and Alzheimer’s disease. The study notes that these replacement cells originate in the blood, suggesting potential new methods to modify them for better brain health.