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Stroke Treatment May Get Big Boost From Blood Flow Discovery

Sept. 13, 2004 - There may be new treatments for stroke, migraine, Alzheimer’s and other brain disorders that plague senior citizens, 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 week in Nature by UBC post-doctoral fellow Sean Mulligan and Brian MacVicar, a professor in the Brain Research Centre and the Dept. 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, Mulligan and MacVicar 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 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.

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

Every year, 50,000 Canadians suffer a stroke, or "brain attack." Another 300,000 people are living with the consequences of stroke, which is the leading cause of adult disability in Canada.

Stroke is the third leading cause of death in the United States.  Each year, about 700,000 people experience a new or recurrent stroke.  About 500,000 of these are first attacks, and 200,000 are recurrent.  Stroke accounted for more than one of every 15 deaths in the country in 2001.

The Brain Research Centre, located at UBC Hospital, comprises more than 150 investigators with multidisciplinary expertise in neuroscience research ranging from the test tube, to the bedside, to industrial spin-offs.

VCHRI is a joint venture between UBC and Vancouver Coastal Health that promotes development of new researchers and research activity.

CIHR is Canada's premier agency for health research. Its objective is to excel, according to internationally accepted standards of scientific excellence, in the creation of new knowledge and its translation into improved health for Canadians, more effective health services and products and a strengthened health care system.

The Canadian Stroke Network includes more than 100 of Canada's leading scientists and clinicians from 24 universities who work collaboratively on various aspects of stroke. The Network, which is headquartered at the University of Ottawa, also includes partners from industry, the non-profit sector, provincial and federal governments Canada Research Chairs are federally funded research positions that are the centerpiece of a national strategy to make Canada one of the world's top five countries for research and development.