X-Message-Number: 17470
From: "Jan Coetzee" <>
Subject: New Blood Vessels 
Date: Fri, 7 Sep 2001 00:56:54 -0400

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New Blood Vessels May Grow After Stroke Damage
By Emma Hitt, PhD 


NEW YORK (Reuters Health) - New animal research suggests that the brain can 
recover some of the blood flow lost to damage from so-called ``mini-strokes.'' 
Scientists say that understanding this process could help them develop therapies
to reduce stroke damage to brain cells and promote the brain's recovery. 


Stroke is the third-leading cause of death in the United States, killing about 
160,000 Americans each year. A stroke occurs when the brain's blood supply is 
reduced, most often by a clot in a blood vessel. Stroke survivors experience 
varying degrees of brain damage. Mini-strokes are short-lived attacks that do 
not leave the same lasting damage, but do indicate that a person is at risk of a
full-blown stroke. 


According to the new study's lead author, Dr. Thomas A. Woolsey of Washington 
University School of Medicine in St. Louis, Missouri, scientists already knew 
that after a mild stroke, tiny blood vessels called capillaries can form and 
some blood vessels appear to change. 


But, he said, ``we are the first group to show these changes directly before and
after a stroke.'' 


In the study, Woolsey's team caused small strokes in the cortex, or outer layer,
of rats' brains by sealing off artery branches that supplied blood to the 
region. They then compared changes to the blood vessels of the cortex 
immediately after and 30 days after they had sealed off the blood supply. 


After 30 days, the blood vessels in the area of the stroke had enlarged and were
able to restore some blood flow to the stroke-damaged area--indicating that the
brain had created new blood-supply pathways, the investigators report in the 
September issue of Stroke: Journal of the American Heart Association. 


According to Woolsey, although the study was performed in rats, some studies in 
humans, as well as data from autopsies, suggest that the same process can take 
place in people. 


``We were surprised by the extent of the changes and are interested in how they 
could relate to changes in the function of the brain in the region of the 
stroke,'' he told Reuters Health. 


The researcher said he also hopes the findings can be applied to recovery from 
serious strokes. 


``We feel now that it is important to investigate safe ways to accelerate the 
vessel changes while reducing the loss of nerve cells so that the impact of 
strokes is less and chances for recovery are greater,'' Woolsey said. 


``We are deeply concerned with the suffering and loss of mobility, speech and 
other results of strokes that affect patients and their families,'' he added. 
``The hope we have from our findings is that a robust process of vessel recovery
from stroke could be optimized to support a good recovery of brain function.''


However, Woolsey added, more studies are needed before these findings can be 
used in stroke recovery. 

SOURCE: Stroke 2001;32. 


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