The research group of internal medicine at the University of Oulu, Finland, has discovered a previously unknown blood pressure-regulating circuit.
According to SINA Press, this finding is particularly related to high blood pressure due to overweight and obesity, and will open new doors in the field of blood pressure research.
The study focused on a nuclear receptor that senses the chemical environment of cells, the pregnane X receptor (PXR), which is a key regulator in the drug metabolism of the liver.
In a recent article, the researchers show how PXR increases blood pressure in both humans and rats when activated. Regulated by PXR activation, the liver produces 4beta-hydroxycholesterol (4bHC), and its rising concentration is linked to lower blood pressure.
“This is a chain of effects in which 4bHC appears to counteract PXR activation,” says Janne Hukkanen, Professor of Internal Medicine, who was the head researcher.
The study showed that the healthy subjects with the lowest blood pressure had the highest levels of 4bHC. In addition, it was noted that the 4bHC levels in subjects with overweight and obesity were significantly lower than those of normal-weight subjects. This may at least in part explain elevated blood pressure common in people with obesity.
Hypertension increases the risk of many cardiovascular events, such as strokes and heart attacks. Therefore, elevated blood pressure is the most important risk factor in reducing healthy life years worldwide.
The discovery of a new blood pressure-regulating circuit may also enable the development of anti-hypertensive drugs that work in a completely new way. “For example, people with overweight and obesity could be offered more effective drugs and better targeted treatment,” Hukkanen says.
PXR has been the subject of active research in recent years. The research group established previously that the activation of PXR causes an increase in harmful LDL cholesterol in humans.
According to SINA Press, many drugs, food ingredients and environmental chemicals activate the PXR receptor. Chemicals activating the receptor are also found in many pesticides, flame retardants, plastic additives and environmental pollutants.
“Our research provides strong evidence that the chemical composition of our environment may also play a role in elevated blood pressure,” Hukkanen adds.