Medical Research Council - London Institute of Medical Sciences

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Brain Defenders

Diversity of brain immune cells called perivascular macrophages and their role in brain injury revealed

07 January 2023

Brain Defenders

Your bloodstream can carry any number of toxins and infections. That’s why your brain is protected from it by the blood-brain barrier, a tight seal allowing nutrients in but keeping potential threats out. However, it also keeps out the blood's immune cells. Thankfully, your brain has its own immune cells, perivascular macrophages (pvMs). These maintain the blood-brain barrier and are involved in immunity. Researchers take a closer look at these cells using mice genetically manipulated with fluorescent tags for macrophage markers. Through fluorescence microscopy of the brain (pictured), the team confirm the presence of a known population of macrophages with the marker Lyve1 (blue) around blood vessels (green, red) but also identify another population with the marker CX3CR1, which perform phagocytosis. What's more, after inducing a stroke in these mice, pvM numbers increased. These cells are, therefore, more diverse than originally thought and respond to the brain injury, stroke.

Written by Lux Fatimathas

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