New research from the University of Virginia School of Medicine is shedding light on the development of the brain’s immune defenses – and how those defenses respond to strokes that strike one in 4,000 babies in the first month of life.
The brain’s frontline defenders are immune cells known as microglia. These cells make up 10%-15% of all cells found in the brain. But their origins have been hotly debated. UVA’s Chia-Yi “Alex” Kuan, MD, PhD, has discovered that many were previously white blood cells known as monocytes. During brain development – and in response to infant strokes – the monocytes undergo an amazing conversion into troops to defend the brain.
“Most people believe that blood monocytes only come into the brain after injury to provoke damage, and then they either die or leave the brain. Some even say monocytes and microglia live in parallel universes,” said Kuan, of UVA’s Department of Neuroscience and its Center for Brain Immunology and Glia (BIG). “But our results showed that many microglial cells actually come from the blood monocytes, both in normal development and after newborn brain injury.”
