March 13, 2009

1 In 5 Strokes Originate In Tiny Brain Arteries

A new study by experts at Britain's Edinburgh University finds that a weakening of the small arteries in the brain may be responsible for 20 percent of strokes.

The brain damage resulting from lacunar strokes, which occur in tiny rather than large arteries, may be caused by a gradual weakening of the artery wall.

Scientists had previously believed this type of stroke was caused only by a reduced blood flow to the brain.  However, the Edinburgh University researchers now believe the weakening takes place in the protective lining of the small arteries.

Called the blood-brain barrier, this protective lining stops potentially dangerous substances from getting into the brain.

The study involved two groups of stroke patients:  one with lacunar stroke and the other with the large artery type. Both groups were injected with magnetic dye and received brain scans that showed how the dye moved through their blood vessels.

The researchers found that more dye leaked out of the blood vessels into the brain in the lacunar patients than it did in the other group, something that could only have occurred if the dye was able to leak through the protective barrier, the researchers said.

"This is an important milestone in the understanding of this common type of stroke and dementia," Joanna Wardlaw, professor of Applied Neuroimaging at Edinburgh University, told BBC News.

"We don't know exactly what causes this weakening of the blood-brain barrier - it may be age, blood pressure or inflammation. More research is required, but we hope the results will help in the search for more treatments to this widespread condition."

The study was supported by the Chest Heart Stroke Scotland, the Chief Scientist Office, the Welcome Trust, the Row Fogo Charitable Trust, the Cohen Charitable Trust and the UK Stroke Association.

The research was published in the Annals of Neurology.  An abstract can be viewed at http://www3.interscience.wiley.com/journal/122226908/abstract


On The Net:

Edinburgh University

The Stroke Association