A New Risk Factor for Alzheimer’s

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Researchers have discovered a new risk factor for Alzheimer’s disease: leaky blood vessels.

An MRI study found that people experiencing mild problems with thinking and memory had much more leaky blood vessels in the hippocampus area of the brain. The study, published in the January 2015 issue of Neuron, also found that blood vessels in the hippocampus tend to become more leaky in all people as they age. But the process is actually accelerated in those likely to develop Alzheimer’s or other forms of dementia.

The findings suggest that it may be possible to identify people at risk for Alzheimer’s by looking at their blood vessels. The results also suggest that a drug to help the body seal up leaky blood vessels could delay or even prevent Alzheimer’s and other forms of dementia.

Scientists used a special type of MRI to study the living brains of more than 60 people. The group included both healthy individuals and people with mild cognitive impairment, which can be an early sign of Alzheimer’s.

The hippocampus is one of the first brain areas affected by Alzheimer’s, so they paid special attention to it.   They found that in some regions of the hippocampus, the permeability of the blood-brain barrier was more than 50 percent higher in people with mild cognitive impairment.

The blood-brain barrier is a special layer of cells that normally prevents bacteria and toxins that circulate in the bloodstream from mixing with the fluid that surrounds brain cells. When it breaks down, toxins leak into the fluid that surrounds brain cells and can eventually damage or kill the cells.

These findings could help explain why people with atherosclerosis and other problems with their blood vessels are more likely to develop Alzheimer’s.