In a study from the National Institute of Neurological Disorders and Stroke, scientists found intensively lowering blood pressure may lead to structural changes in the brain that help it clear away toxins and other byproducts, potentially reducing the risk for dementia.
This is the first study to look at whether intensive blood pressure treatment can slow or reverse the volume of brain tissue taken up by perivascular spaces, the pathways around blood vessels used to clear toxins.
The researchers say that if the brain cannot properly clear toxins and metabolic byproducts, they will accumulate and may contribute to the development of dementia.
Some research has proposed that the pulsations of the cerebral arteries with each heartbeat help to drive the clearance of these toxic brain byproducts in the perivascular spaces.
However, high blood pressure over the long term stiffens arteries, impairing function and the ability to clear toxins, resulting in the enlargement of perivascular spaces.
A blood pressure reading has two measurements: systolic pressure, the top number, measures the force against artery walls when the heart beats; diastolic pressure, the bottom number, measures the same force between beats.
The American Heart Association defines hypertension, or high blood pressure, as a systolic reading of 130 mmHg or higher or a diastolic reading of 80 mmHg or higher.
In the study, the team compared magnetic resonance imaging scans of the brains of 442 older people with high blood pressure who were given either intensive treatment (lowering systolic blood pressure to 120 mmHg) or standard treatment (lowering the systolic to 140 mmHg).
Brain scans were taken at the time of enrollment and after an average follow-up of 3.9 years.
As people age or have more cardiovascular risk factors, perivascular spaces in the brain can become enlarged, blocking the pathway so toxins don’t clear the brain.
The volume of brain tissue in these spaces was similar for both groups when the study began.
But after nearly four years, the team found only the group given intensive blood pressure treatment saw a significant decrease in volume.
This suggests that aggressive treatment may reverse the effects of high blood pressure on these pathways.
The team says the next step is to determine how perivascular spaces relate to cognition and cognitive decline in the SPRINT-MIND trial.
If you care about blood pressure, please read studies about supplements that could help reduce high blood pressure, and certain plant-based foods could benefit people with high blood pressure.
For more information about blood pressure, please see recent studies about new link between potatoes and high blood pressure, and results showing black tea may effectively prevent high blood pressure.
The study was conducted by Dr. Kyle Kern et al and presented at the American Stroke Association’s International Stroke Conference.
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