Light and Genetic Probes Untangle Dynamics of Blood Flow Through the Brain’s Vast Capillary Network

The human brain has over 400 miles of total vasculature, yet little is known about the tiny capillaries that make up much of this intricate labyrinth. Understanding how this vast network regulates blood flow in the brain could hold the key to new treatments for neonatal and childhood neurologic conditions, such as stroke and hypoxia, and issues of aging like dementia and Alzheimer’s disease.
While the human brain has over 400 miles of total vasculature, little is known about the tiny capillaries that make up much of this intricate labyrinth of blood vessels critical for delivering oxygenated blood and nutrients to billions of brain cells.
According to Dr. Andy Shih, a principal investigator in the Center for Developmental Biology and Regenerative Medicine at Seattle Children’s Research Institute, understanding how this vast network regulates blood flow in the brain could hold the key to new treatments for neonatal and childhood neurologic conditions, such as stroke and hypoxia, and issues of aging like dementia and Alzheimer’s disease.
“Insufficient blood flow contributes to many of the common neurologic problems seen in children and adults,” he said. “Yet, because we can’t see the capillaries, which measure about 1/10th the thickness of hair, with in vivo clinical imaging techniques, determining how blood travels through this densely packed bed of vessels has remained elusive.”
Wanting to get a closer look, Shih and fellow scientists, Dr. Andree-Anne Berthiaume and Dr. David Hartmann, applied special techniques called two-photon imaging and optogenetics to isolate and study brain capillaries in animal models. Their findings published today in Nature Neuroscience describe the dynamics that govern capillary blood flow in the brain and have broad implications for future avenues of brain research.
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