Scientists find new cause of high blood pressure

Scientists at Waipapa Taumata Rau, University of Auckland have discovered that a small organ, linked to the brain, contributes to high blood pressure, and may improve treatment in the future. 

The carotid body in the neck responds to low oxygen by making people breathe harder through stimulating the brain’s ‘fight or flight’ response.  

Using a rat model, the scientists found that the ‘carotid body’ responds to high blood pressure by activating the sympathetic nervous system, like a ‘fight or flight’ response.

Authors suggest that this may explain why some patients remain at high risk of cardiac events – heart attack and stroke – even when elevated blood pressure is brought down. See Circulation Research. 

“This is significant because we know that, for a lot of people, lowering their blood pressure doesn’t necessarily reduce their risk of heart attack or stroke,” says Dr Audrys Pauza, lead researcher.  “That means current medications are not working for all patients and could be treating the wrong culprit.” 

Pauza likens it to trying to slow a speeding car by applying the brake (lowering blood pressure) but not reducing pressure on the accelerator (the carotid body). 

There are currently two medications that reduce activity in the human carotid body, which could be candidates for reducing people’s risk of heart attacks and strokes. But first, scientists need to confirm humans respond in the same way as the rats in this study. 

Professor Julian Paton, director of the University’s Manaaki Manawa, Centre for Heart Research, has already found in earlier studies that the activity of the carotid body is stimulated by the same mechanism in both rats and humans, meaning scientists are hopeful this discovery could help human patients in the future. 

“We have found that the carotid body doesn’t just detect low oxygen and promote breathing, it actively causes high blood pressure,” Paton says. “If we can successfully target the carotid body, we may have a lot more success in both bringing blood pressure down and preventing heart attacks and strokes.” 

• Learn about animal research at the University of Auckland.