Areas of brain hurt by high blood pressure and involved in dementia identified

Specific areas of the brain associated with damage from high blood pressure that may contribute to the development of dementia have been identified for the first time, researchers have said.

The findings could help develop targeted therapies for people suffering debilitating symptoms of dementia such as memory loss.

High blood pressure has long been a known cause of dementia and damage to brain function. The study, published in European Heart Journal on Tuesday, shows how that happens.

Researchers first gathered information from thousands of UK patients, including magnetic resonance imaging of brains, genetic analyses and observational data to look at the effect of high blood pressure on cognitive function. Researchers then checked their findings in a separate, large group of patients in Italy.

“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,” said Prof Tomasz Guzik, a cardiovascular medicine expert at University of Edinburgh.

“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.”

The study could help understand how high blood pressure affects the brain and causes cognitive problems.

“We hope that our findings may help us to develop new ways to treat cognitive impairment in people with high blood pressure,” Prof Guzik said.

“We may be able to 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 impairment in patients most at risk.”

High blood pressure occurs in 30 per cent of people worldwide and an additional 30 per cent show the initial stages of the disease. Previous studies have shown that it affects how well the brain works and that it can cause long-term changes.

But until now it was not known exactly how high blood pressure damaged the brain and which specific regions were affected.

Researchers used MRI images from more than 30,000 participants in the UK Biobank study and genetic information from three groups — UK Biobank, Cogent and the International Consortium for Blood Pressure.

They found changes to nine parts of the brain were related to higher blood pressure and worse cognitive function, included the putamen, which is a round structure in the base of the front of the brain, responsible for regulating movement and influencing various types of learning.

The changes included decreases in brain volume and the amount of surface area on the brain cortex.

“Our study has, for the first time, identified specific places in the brain that are potentially causally associated with high blood pressure and cognitive impairment,” said Prof Mateusz Siedlinski from Poland’s Jagiellonian University Medical College, one of the study's authors.

Co-author Professor Joanna Wardlaw, from University of Edinburgh, said: “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.”

Other areas affected were the anterior thalamic radiation, anterior corona radiata and anterior limb of the internal capsule, which are regions of white matter that connect and enable signalling between different parts of the brain.

The anterior thalamic radiation is involved in executive functions, such as the planning of simple and complex daily tasks, while the other two regions are involved in decision-making and the management of emotions.