Mechanism for regulating brain blood flow discovered by BC researchers

Ottawa, ON – September 20, 2004 -There may be new treatments for stroke, migraine, Alzheimer’s and other brain disorders, thanks to the discovery of a mechanism for regulating brain blood flow made by researchers at the University of British Columbia.

Scientists found that astrocytes – cells that surround nerve cells and all blood vessels in the brain – have a primary role in regulating blood flow within the brain, and hold promise as a target for new therapies.

The findings of the two-year study funded by the Canadian Institutes of Health Research (CIHR) and the Canadian Stroke Network were published this month in Nature by UBC post-doctoral fellow Sean Mulligan and Brian MacVicar, a professor in the Brain Research Centre and the department of psychiatry at UBC and an investigator with the Vancouver Coastal Health Research Institute (VCHRI).

Using a new technique that they developed to study brain blood flow, the researchers found that a rise of calcium within the astrocytes instructs the blood vessels to constrict, which alters blood flow.

Brain blood flow supplies energy for brain activities. Vessel contraction and dilation is a normal part of brain functioning, however, improperly regulated flow can result in brain disorder or damage. Calcium flow in the brain is not influenced by diet.

“This is an exciting find because it gives us a new site to investigate,” says Dr MacVicar, Canada research chair in neuroscience. “This discovery highlights the complex communication between astrocytes and blood vessels, and research can now be focused on understanding and controlling these communication pathways.”

The discovery that astrocytes cause constriction upsets earlier theories that astrocytes might cause vessels to dilate, he adds.

“This discovery will serve as a gateway to new treatments and is of fundamental importance in understanding how the brain regulates blood flow,” says Dr Bruce McManus, scientific director of the Institute of Circulatory and Respiratory Health of the Canadian Institutes of Health Research (CIHR).

“This powerful research gives us new targets against which to develop a new generation of drugs to minimize stroke damage to the brain,” adds Dr Antoine Hakim, CEO and scientific director of the Canadian Stroke Network.

Next steps in the research include determining how to block the calcium in astrocytes to reduce damage caused by inadequate brain blood flow. Dr MacVicar estimates treatments may be available in five to 10 years.