High Blood Pressure Could Actually Be A Brain Issue, Study Suggests

Blood pressure, in theory, sounds like a simple concept: it’s down to how much blood the heart has to pump, and how easy it is for that blood to move through our arteries.

But the causes of high blood pressure (hypertension), which has been described as a “silent killer” because it often has no symptoms, are more complex than you might think.

Irregular sleep, air pollution, loneliness, and even a lack of potassium may all play a role in the common condition’s development. 

And according to a Circulation Research study, there might be another factor at play – a brain area called the lateral parafacial (pFL) region. 

What is the pFL region?

This region is located in the brainstem, which is one of the oldest parts of the brain and helps to control functions like breathing, digestion and heart rate.

The study’s lead author, the University of Auckland’s Professor Julian Paton, explained: “The lateral parafacial region is recruited into action, causing us to exhale during a laugh, exercise, or coughing.”

These amount to “forced” exhalations that we can’t fully control. Instead of being driven solely by our lungs, these uncontrollable breaths recruit our abdominal muscles. 

What does that have to do with high blood pressure? 

Researchers found that in rats, the pFL region also seemed to connect to a nerve that restricted blood vessels. 

And the tighter our blood vessels, the higher our blood pressure tends to get. When scientists activated the pFL region of some rats’ brains, it seemed to set off a series of reactions that raised their blood pressure.

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

“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.”

Changes in how we breathe (especially if we start relying on the abdominal muscles used for ‘forced’ breaths) might therefore trigger high blood pressure. 

That might explain why health issues like obstructive sleep apnoea, which involves loud snoring and periods of not breathing at night, have been linked to higher blood pressure.

Is there anything we can do about pFL changes and blood pressure? 

It can be hard to treat specific areas of the brain, said Prof Paton.

But they found that the pFL seems to be activated by signals from “carotid bodies”, which are little clusters of cells that live in our neck.

It’s a lot easier to target these cells precisely than it would be to send treatment to a specific part of the brain. So, Prof Paton shared: “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.”

The study has only been conducted on rats so far, and much more research will be needed before scientists can begin trialling potential treatments. 

Still, the paper concluded by proposing that suppressing pFL neurons could have “therapeutic potential”.