Pericyte Death in Stroke Causes Long-term Brain Damage

Remarkable new research suggests that the long-term brain damage which frequently accompanies stroke results from the death of a cell type largely overlooked in classical neuroanatomy. These contractile cells – called pericytes – form a net around capillaries and control blood flow by contracting and relaxing. Stroke causes pericytes to contract and die, leading to a reduction in downstream blood flow and neuronal death due to insufficient delivery of oxygen and nutrients. In the clinic, this leads to brain damage, which can significantly impair a patient’s quality of life and independence.

The research, conducted by scientists from UCL, the University of Oxford and the University of Copenhagen, provides new insights into the regulation of brain blood flow in health and disease. Until now, many scientists believed that brain blood flow was controlled solely by arterioles, blood vessels that branch out from large arteries into small capillaries. The results published this week in the journal Nature reveal that blood flow in the brain is in fact primarily controlled by pericytes.

In addition to demonstrating that pericytes control brain blood flow, the study reveals that they constrict and die around capillaries after stroke, causing a long lasting reduction in brain blood flow, and permanent damage to brain cells. The scientists found that application of certain small molecule drugs halved the extent of pericyte death. They now hope to build on this by developing and testing similar drugs in animal models, and eventually clinical trials, with a view to minimising brain damage after stroke.