Arterial hypertension is a very frequent health problem, since it is estimated that it affects around 30% of the world population. It has been proven that it influences the functioning of the brain and that over time it can cause changes in this organ, but it was unknown how they occurred or what were the specific areas that were damaged. Now, for the first time, an international team of scientists has identified which regions of the brain deteriorate due to high blood pressure and how this condition that contributes to the development of dementia occurs.
The researchers collected information from combining brain magnetic resonance imaging (MRI), genetic analysis, and other data from thousands of patients to analyze the effects of elevated blood pressure levels on cognitive function, and then verified the results obtained in a large independent group of patients in Italy. The findings have just been published in the European Heart Journal.
“Using this combination of imaging, genetic, and observational approaches, we have identified specific parts of the brain that are affected by increases in blood pressure, including areas called the putamen and specific regions of white matter. We think these areas could be where high blood pressure affects cognitive function, such as memory loss, thinking skills, and dementia. When we verified our findings by studying a group of patients in Italy who had high blood pressure, we found that the parts of the brain that we had identified were indeed affected,” said Tomasz Guzik, Professor of Cardiovascular Medicine at the University of Edinburgh, UK. and the Faculty of Medicine of the Jagiellonian University of Krakow (Poland), which has led the research.
Predict memory loss in patients with hypertension
Brain MRI data from more than 30,000 UK Biobank study participants, genetic information from the UK Biobank Genome-Wide Association Study (GWAS) and two other international groups (COGENT) were used to conduct the research. and the International Consortium for Blood Pressure) and a technique called Mendelian randomization, to test whether high blood pressure was actually causing changes in certain areas of the brain, rather than just one more factor associated with these changes.
The study “may help identify people at risk of cognitive decline in the early stages and potentially target therapies more effectively in the future.”
“Mendelian randomization is a way of using genetic information to understand how one thing affects another,” explained Professor Guzik. “In particular, it tests whether something is potentially causing a certain effect, or whether the effect is just a coincidence. It works by using a person’s genetic information to see if there is a relationship between genes that predispose to higher blood pressure and outcomes. If there is a relationship, then it is more likely that high blood pressure is causing the result. This is because the genes are passed down randomly from the parents, so they are not influenced by other factors that could confound the results. In our study, if a gene that causes high blood pressure is also linked to certain brain structures and their function, then it suggests that high blood pressure might actually be causing brain dysfunction there.”
The results showed that changes in nine areas of the brain were linked to higher blood pressure and poorer cognitive function. These included the putamen—a round structure at the base of the front of the brain that regulates movement and influences various types of learning—the anterior thalamic radii, the anterior corona radiata, and the anterior arm of the internal capsule. , which are regions of white matter that connect and allow signaling between different parts of the brain. The anterior thalamic radiation is involved in executive functions, such as planning simple and complex daily tasks, while the other two regions are involved in decision-making and managing emotions.
Changes observed in these areas included reductions in brain volume and the amount of surface area in the cerebral cortex, alterations in the connections between different areas of the brain, and changes in measures of brain activity. “Our study has for the first time identified specific locations in the brain that are potentially causally associated with high blood pressure and cognitive decline. This was only possible thanks to the availability of data from the UK Biobank, including magnetic resonance imaging of the brain, and previous research that identified genetic variants that affect the structure and function of more than 3,000 areas of the brain. Study author Associate Professor Mateusz Siedlinski, also a researcher at the Jagiellonian University Faculty of Medicine.
Professor Joanna Wardlaw, head of Neuroimaging Sciences at the University of Edinburgh, and co-author of the study, recalled that high blood pressure has long been known to be a risk factor for cognitive decline, but it was not clear to what extent. way damaged the brain, and that their study “shows that specific regions of the brain are at particularly high risk of damage from blood pressure, which may help identify people at risk of cognitive decline in the early stages and potentially guide therapies more effectively in the future.”
“We hope our findings can help us develop new ways to treat cognitive decline in people with high blood pressure. Studying the genes and proteins in these brain structures could help us understand how high blood pressure affects the brain and causes cognitive problems. Furthermore, by looking at these specific regions of the brain, we can predict who will develop memory loss and dementia faster in the context of high blood pressure. This could help with precision medicine so that we can target more intensive therapies to prevent the development of cognitive decline in patients at higher risk,” concludes Tomasz Guzik.
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