A new study — led by the University of Edinburgh in the United Kingdom — has now uncovered how a disease that affects the brain's small blood vessels contributes to dementia and stroke.
The disease in question is called cerebral small vessel disease (CSVD).
They made some important discoveries. They identified, for example, a mechanism through which blood vessel changes from CSVD harm the myelin covering of nerve fibers that carry signals between brain cells.
The scientists also showed how certain drugs reversed the blood vessel changes and prevented damage to the nerve fibers in the rats' brains.
Brain scans of individuals with dementia often show abnormalities in white matter, which consists mostly of nerve fibers and their myelin covering.
But until this study, the underlying mechanisms implicating CSVD as a driver of myelin damage in white matter were unknown.
Should the mechanism be the same in human CSVD, these findings could pave the way to new treatments for dementia and stroke.
Dr. Sara Imarisio, who is head of research at Alzheimer's Research UK — one of the organizations that sponsored the study — says that the findings point to "a promising direction for research into treatments that could limit the damaging effects of blood vessel changes and help [to] keep nerve cells functioning for longer."
Closer investigation revealed that the rats that developed CSVD had a mutated form of an enzyme called ATPase, and that this led to dysfunction of their endothelial cells. The mutation has also been found in the brain tissue of humans with CSVD.
In a final set of experiments, the scientists showed how using drugs to stabilize the endothelial cells "could reverse the white matter abnormalities in early-stage SVD in the rat model, suggesting a potential therapeutic approach."
Prof. Williams and team explain that more research is now needed to find out whether the drugs work after CSVD has established itself and whether they might also "reverse the symptoms of dementia."