Brain Can Increase Blood Flow After Stroke
Vessels widen, lengthen in rats, study shows
THURSDAY, Sept. 6, 2001 (HealthDayNews) -- An animal study has provided direct evidence that the brain responds to a stroke by creating better blood flow around the damaged area.
The challenge now is to translate that finding into help for stroke patients, says Dr. Thomas A. Woolsey, professor of neuroscience and neurosurgery at Washington University School of Medicine and a member of the team reporting the finding in the September issue of Stroke: Journal of the American Heart Association.
It is a daunting challenge, Woolsey says. "The nervous tissue that you want to preserve doesn't survive a lack of blood flow very long. Time is not something you have a lot of if you want to prevent the brain from dying."
Nevertheless, he says this is the first direct observation of what many stroke experts have believed in theory -- that there is a natural protective response that improves blood flow around the region of the brain where a stroke cuts off the blood supply.
"We're very interested in clinical applications. Now that we know the process occurs, the next step is to accelerate it," Woolsey says.
In the study, Woolsey and his colleagues created mini-strokes in rats by cutting off blood flow to carefully defined regions of their brains. They then assessed the status of blood vessels around the affected regions for up 30 days afterward.
Rather than growing new blood vessels, "older vessels proliferate. They become bigger and longer," says lead study author Dr. Ling Wei, assistant professor of neurology at Washington University.
The study identified two molecules -- basic fibroblast growth factor and vascular endothelial growth factor -- that stimulated the response, Wei says. The growth factors also stimulate growth of the nerve cells surrounding the damaged area, she says.
The baton now is passing to "our colleagues at Washington University with remarkable expertise in stroke," Woolsey says. They are exploring what he calls "the logistical problem" of achieving the growth of blood vessels and nerve cells in human patients.
The new study is a small step toward helping people who suffer strokes, "but we are in a remarkable age because many people have made many small steps," Woolsey says..
What To Do
While practical applications for the research may be many years away, the sensible thing to do is to follow the rules to reduce the risk factors for stroke, such as high blood pressure, high blood cholesterol, smoking and physical inactivity.
Information about stroke and reducing the risk of suffering one is offered by the American Heart Association and the National Institute of Neurological Disorders and Stroke.