Specific regions of the brain that are damaged by high blood pressure have been identified for the first time.
It is hoped the international study, led by researchers at the University of Edinburgh, UK, will help the development of new ways to treat cognitive impairment in people with high blood pressure.
Study leader Professor Tomasz Guzik, professor of cardiovascular medicine at the University of Edinburgh (UK) and Jagiellonian University Medical College, Krakow, Poland, said researching the genes and proteins in brain structures could help to increase understanding into how high blood pressure affects the brain and causes cognitive problems.
The study, published in today’s European Heart Journal, involved examining data from a combination of magnetic resonance imaging (MRI) of brains, genetic analyses and observational data from thousands of patients.
Prof Guzik said: “By 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 white matter regions.
“We thought these areas might be where high blood pressure affects cognitive function, such as memory loss, thinking skills and dementia. When we checked our findings by studying a group of patients in Italy who had high blood pressure, we found that the parts of the brain we had identified were indeed affected.”
He added that by looking at these specific regions of the brain, clinicians may be able to predict who will develop memory loss and dementia faster in the context of high blood pressure, which could help with precision medicine.
Although studies have shown that high blood pressure affects how well the brain works and that it can cause long-term changes, it was not known it damages the brain and which specific regions are affected.
Prof Guzik and an international team of researchers used brain MRI imaging data from more than 30,000 participants in the UK Biobank study, genetic information from genome-wide association studies (GWAS) from UK Biobank and two other international groups (COGENT and the International Consortium for Blood Pressure).
They also used Mendelian randomisation, to see if high blood pressure was the cause of changes to specific parts of the brain rather than just being associated with these changes.
They found changes to nine parts of the brain were related to higher blood pressure and worse cognitive function, including the putamen, which is responsible for regulating movement and influencing various types of learning.
Other areas affected were the anterior thalamic radiation, anterior corona radiata and anterior limb of the internal capsule, which connect and enable signalling between different parts of the brain.
The changes included decreases in brain volume and the amount of surface area on the brain cortex, changes to connections between different parts of the brain, and changes in measures of brain activity.
Study co-author Professor Joanna Wardlaw, head of neuroimaging sciences at the University of Edinburgh, said: “It has been known for a long time that high blood pressure is a risk factor for cognitive decline, but how high blood pressure damages the brain was not clear.
“This study shows that specific brain regions are at particularly high risk of blood pressure damage, which may help to identify people at risk of cognitive decline in the earliest stages, and potentially to target therapies more effectively in future.”
The authors point to limitations of the study that include participants in the UK Biobank study being mainly white and middle-aged.
Siedlinski M, Carnevale L, Xu X et al. Genetic analyses identify brain structures related to cognitive impairment associated with elevated blood pressure. European Heart Journal 208 March 2023; doi:10.1093/eurheartj/ehad101
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