Heart disease can lead to deadly health issues, including arrhythmia and heart attack. It’s also a widespread ailment, with the CDC estimating that more than 18 million American adults have coronary artery disease, the most common form of heart disease. A new study finds that if you live with this condition, its disruption to blood flow in the brain can also lead to dementia and an increase in beta-amyloid protein.
Researchers from the University of Sheffield in the United Kingdom examined the impact of heart disease on specific brain activity. Their findings, published in the journal eLife, show that insufficient blood flow due to heart disease can lead to neurons not getting the blood they need. The resulting brain dysfunction could ultimately lead to dementia, even before the build-up of plaque in the brain’s blood vessels.
Dr. Osman Shabir, lead author and researcher from the University of Sheffield’s Neuroscience and Healthy Lifespan Institutes, says, “We’ve discovered that heart disease in midlife causes the breakdown of neurovascular coupling, an important mechanism in our brains which controls the amount of blood supplied to our neurons. This breakdown means the brain doesn’t get enough oxygen when needed, and in time, this can lead to dementia.”
To investigate heart disease and neurovascular coupling, the team used mouse models with Alzheimer’s disease and atherosclerosis, or build up of plaque in the brain’s blood vessels. They found that atherosclerosis and neurovascular decline were linked with significantly reduced blood volume, changed levels of oxyhemoglobin and deoxyhemoglobin, and global neuroinflammation. They also found that when combined with Alzheimer’s genetic risk, heart disease tripled the amount of beta-amyloid protein in the brain and increased the level of an inflammatory gene known as IL1.
The study notes, “These findings suggest that systemic atherosclerosis can be detrimental to neurovascular health and that having cardiovascular comorbidities can exacerbate pre-existing Alzheimer’s-related amyloid-plaques.”
The team says this research is important to better understand the link between heart disease and dementia. Going forward, they will be looking at how an arthritis drug that targets IL1 may reverse or reduce the brain dysfunction linked with heart disease.