Small Heart Change Can Presage Big Brain Loss
But what has surprised the Vanderbilt researchers is how a very, very subtle change in heart muscle function can begin to cause a deterioration in thinking abilities and provide an early sign of long-term brain problems. In tests of more than 300 people between the ages of 60 and 92, the scientists used a technique called cardiac magnetic resonance to tease out slight changes in the pumping action of the heart muscle. With this highly sensitive test they were able to uncover tiny contraction differences that don’t show up in more common medical measurements. They aren’t detected by the types of tests a cardiologist is likely to give you. The Vanderbilt researchers measured what’s called global longitudinal strain – GLS – which indicates a particular type of contraction of the heart muscle. Even when heart function looks fine on less sensitive tests, they found that GLS changes coincided with the beginning of memory issues. Although the brain seems to have effective ways to keep blood flowing through its vessels even when the heart muscle struggles, the studies show that when the GLS slips, the brain suffers. The researchers suggested several possible reasons:1- Less blood means that brain cells can’t form as many of the proteins necessary to create the extra neuron connections (synapses) necessary for learning and memory.
- The reduced blood flow causes problems with the blood-brain barrier, allowing toxins to move from the blood into brain cells, damaging and killing off neurons.
- The toxins coming into brain cells are particularly destructive to the hippocampus, the part of the temporal lobes that acts as the brain’s memory and language center.
