Ideal blood pressure may remodel brain clearance pathways linked to brain health, dementia

Key points of the research:

Close review of the MRI scans found that more intensive treatment of high blood pressure (aimed at achieving a systolic pressure of less than 120 mm Hg) was more effective than a less intensive treatment goal of 140 mm Hg systolic at achieving of a positive structural change in the perivascular brain. space: pathways that are important for the clearance of toxins and other byproducts.

If the brain can’t properly clear metabolic byproducts, they accumulate and may contribute to the development of dementia, the researchers said.

The new findings are from MRI scans of several hundred adults in the SPRINT-MIND trial that previously found that intensive lowering of blood pressure slowed cognitive impairment.

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(NewMediaWire) – February 02, 2023 – DALLAS Among people who received more intensive treatment for high blood pressure, MRI scan evaluations showed a positive change in brain structures involved in its ability to clear toxins and other byproducts, according to the preliminary research that will be done. presented at the American Stroke Association International Stroke Conference 2023. The meeting, held in person in Dallas and virtually, February 8-10, 2023, is the world’s premier meeting for researchers and clinicians dedicated to stroke science and brain health.

The study is the first to examine whether intensive blood pressure treatment can slow or reverse structural changes associated with the volume of the brain’s perivascular spaces, the areas of the brain around blood vessels that are involved in clearing toxins and other byproducts. . These areas tend to enlarge as people age or have more cardiovascular risk factors.

“If the brain cannot properly clear toxins and metabolic byproducts, they will accumulate and may contribute to the development of dementia,” said Kyle Kern, MD, MS, the study’s lead author and a clinical investigator in the intramural stroke branch. National Institute of Neurological Disorders and Stroke, a division of the National Institutes of Health in Bethesda, Maryland. “Some research has suggested that the pulsations of the cerebral arteries with each heartbeat help to promote clearance of these toxic brain byproducts in the perivascular spaces. However, long-term high blood pressure hardens the arteries, impairing function and the ability to clear toxins. , resulting in expansion of the perivascular spaces.”

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Researchers analyzed brain MRI scans for 658 participants (mean age 67 years, 60% women) of the SPRINT-MIND MRI substudy. The trial began in 2010 and the last MRI scan was completed in July 2016. All participants had high blood pressure, but none had previously been diagnosed with diabetes (Type 1 or 2), dementia or stroke.

After a median follow-up of 3.9 years, 243 people in the intensive treatment arm (systolic blood pressure goal of 120 mm Hg) and 199 people in the standard treatment arm (systolic blood pressure goal of 140 mm Hg ) had before and after MRI. scans that were analyzed for the percentage of brain tissue taken from perivascular spaces. Participants were screened at seven MRI sites across the US: University of Alabama at Birmingham, Boston University, Vanderbilt University, Wake Forest University, University of Miami, University of Pennsylvania, and Case Western Reserve University.

On MRI scans obtained when the study began, the percentage of brain tissue occupied by perivascular spaces was higher among patients who were older and had a greater volume of white matter hyperintensity (bright areas of increased on an MRI scan which are the most established markers of damage to small blood vessels in the brain). These patients also had more brain atrophy, another marker of aging and declining brain health.

After controlling for the age and gender of the participants, and the study site where the MRIs were performed, the analysis revealed:

At the start of the study, the volume of the perivascular spaces was similar between participants in the two blood pressure treatment groups.

After almost 4 years of treatment for high blood pressure, the volume of the perivascular spaces was significantly reduced in the intensive treatment group, but had not changed in the standard treatment group.

“Previous research has confirmed that effective blood pressure control is important for brain health. Our secondary analysis findings from SPRINT-MIND MRI suggest that intensive blood pressure control may be beneficial by reducing brain toxin damage.” the brain and byproduct clearance pathway,” Kern said.

While the original SPRINT-MIND MRI study showed that intensive blood pressure control can slow the accumulation of white matter hyperintensities, this substudy found that it can contribute to reversing the effects of high blood pressure in the perivascular spaces.

“These results also suggest that perivascular spaces are more dynamic, and further research is needed to determine the relationship between perivascular space change and progression of white matter hyperintensity,” Kern said.

The study is limited in the available data and the scope of knowledge that can be interpreted from the data. This includes the inability to determine whether the change in perivascular spaces improves thinking ability, or whether it is a byproduct of blood pressure treatment unrelated to cognition or cognitive decline.

“The next step is to determine how perivascular spaces relate to cognition and cognitive decline in the SPRINT-MIND trial. This trial includes high-quality assessments of cognitive function at multiple time points, and future investigations from the trial will describe how connect the perivascular spaces. for the effect of intensive blood pressure control on cognitive decline,” Kern said.

According to the American Heart Association, normal blood pressure is below 120/80 mm Hg. For adults, if the systolic pressure (the main number) is 120 to 129 mm Hg, and the diastolic pressure is less than 80 mm Hg, this is classified as high blood pressure. High blood pressure is a systolic pressure of 130 mm Hg or higher, or a diastolic pressure of 80 mm Hg or higher, that remains high over time.

“These new findings provide early evidence that it may be possible to reduce the size of the perivascular space with an intensive reduction in systolic blood pressure. While not yet proven, the implication is that intensive reduction in systolic blood pressure may be associated with ultimately with better brain clearance of toxins and metabolic byproducts and thus, provide a better chance of maintaining brain health,” said Philip B. Gorelick, MD, MPH, FAHA, chair of the Health Sciences Subcommittee of American Heart Association Brain and Ken & Ruth Davee Professor of Neurology. The Department of Neurology at Northwestern University Feinberg School of Medicine in Chicago, which was not involved in the study.

Co-authors are Ilya M. Nasrallah, MD, Ph.D., and Clinton B. Wright, MD, MS The authors’ findings are listed in the abstract.

The study was funded by the National Institute of Neurological Disorders and Stroke, a division of the National Institutes of Health.

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Additional resources:

The International Conference of the American Stroke Association (ISC) is the world’s leading meeting dedicated to the science and treatment of cerebrovascular diseases. ISC 2023 will be held in person in Dallas and virtually, February 8-10, 2023. The three-day conference will feature more than a thousand compelling presentations in categories highlighting basic, clinical, and translational sciences as research evolves toward a better understanding of pathophysiology of stroke in order to develop more effective therapies. Engage with the International Stroke Conference on social media via #ISC23.

About the American Stroke Association

The American Stroke Association is dedicated to saving people from stroke, the no. 2 of deaths in the world and a leading cause of severe disability. We join millions of volunteers to fund innovative research, fight for stronger public health policies and provide lifesaving tools and information to prevent and treat stroke. The Dallas-based association officially began in 1998 as a division of the American Heart Association. To learn more or get involved, call 1-888-4STROKE or visit stroke.org. Follow us on Facebook, Twitter.

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