New Zealand researchers identify brain link to high blood pressure

Scientists have discovered that a part of the brain may be behind high blood pressure.

The lateral parafacial region sits in the brainstem – the oldest part of the brain – which controls automatic functions such as digestion, breathing, and heart rate.

“The lateral parafacial region is recruited into action causing us to exhale during a laugh, exercise or coughing,” says lead researcher Professor Julian Paton, director of Manaaki Manawa, Centre for Heart Research at Waipapa Taumata Rau, University of Auckland.

“These exhalations are what we call ‘forced’ and driven by our powerful abdominal muscles.

“In contrast, a normal exhalation does not need these muscles to contract, it happens because the lungs are elastic.”

Now researchers found that this area also connects to nerves that tighten blood vessels, a mechanism that raises blood pressure.

“We’ve unearthed a new region of the brain that is causing high blood pressure. Yes, the brain is to blame for hypertension!” says Paton.

“We discovered that, in conditions of high blood pressure, the lateral parafacial region is activated and, when our team inactivated this region, blood pressure fell to normal levels.”

This means changes in breathing patterns – especially those involving strong abdominal muscle contractions – can trigger high blood pressure; thus, any diagnosis of abdominal breathing in patients with high blood pressure may reveal the cause and hence direct appropriate treatment.

The paper has just been published in one of the world’s top specialist journals – Circulation Research.

‘Can we target this brainstem region?’

The next question was whether the brainstem region could be treated with a medication.

“Targeting the brain with drugs is tricky because they act on the entire brain and not a selected region such as the parafacial nucleus,” says Paton.

Then came a major breakthrough. The researchers discovered that this region is activated by signals from outside the brain – from the carotid bodies, tiny clusters of cells in the neck near the carotid artery that sense oxygen levels in the blood.

These can be targeted safely with medication.

“Our goal is to target the carotid bodies, and we are importing a new drug that is being repurposed by us to quench carotid body activity and inactivate ‘remotely’ the lateral parafacial region safely, i.e., without needing to use a drug that penetrates the brain.”

This finding could lead to new treatments for high blood pressure, especially for people who also have sleep apnoea as we know carotid bodies are activated in these patients when they stop breathing at night.