GLP-1: The Missing Link of Diabetes and Hypertension
An international team of researchers has finally cracked the puzzle of why so many patients with hypertension also have diabetes. Their discovery has shown that glucagon-like peptide-1 (GLP-1) couples the body’s control of blood glucose and blood pressure.
Senior Author Professor Julian Paton at the University of Auckland, said: “We’ve known for a long time that hypertension and diabetes are inextricably linked and have finally discovered the reason, which will now inform new treatment strategies.”
The study is published online in Circulation Research.
It has long been known that GLP-1 is released from the wall of the gut after eating and acts to stimulate insulin from the pancreas to control blood sugar levels. However, the researchers found that GLP-1 also stimulates the carotid body, a chemoreceptor located in the neck.
Researchers used RNA sequencing to read all the messages of the expressed genes in the carotid body in rats with and without high blood pressure. This led to the finding that the receptor that senses GLP-1 is located in the carotid body, but less so in hypertensive rats.
David Murphy, Professor of Experimental Medicine from Bristol Medical School: Translational Health Sciences (THS) and senior author, explained: “Locating the link required genetic profiling and multiple steps of validation. We never expected to see GLP-1 come up on the radar, so this is very exciting and opens many new opportunities.”
Professor Paton added: “The carotid body is the convergent point where GLP-1 acts to control both blood sugar and blood pressure simultaneously; this is coordinated by the nervous system which is instructed by the carotid body.”
Even when on medication, many patients with hypertension and/or diabetes are at high risk of life-threatening cardiovascular disease. This is because most medications only treat symptoms and not causes of high blood pressure and high sugar.
Professor Rod Jackson, an epidemiologist from the University of Auckland, said: “We’ve known that blood pressure is notoriously difficult to control in patients with high blood sugar, so these findings are really important because by giving GLP-1 we might be able to reduce both sugar and pressure together, and these two factors are major contributors to cardiovascular risk.”
Lead author Audrys Pauža, PhD student in the Bristol Medical School, added: “The prevalence of diabetes and hypertension is increasing throughout the world, and there is an urgent need to address this.
“Drugs targeting the GLP-1 receptor are already approved for use in humans and widely used to treat diabetes. Besides helping to lower blood sugar these drugs also reduce blood pressure, however, the mechanism of this effect wasn’t well understood.
“This research revealed that these drugs may actually work on the carotid bodies to enact their anti-hypertensive effect. Leading from this work, we are already planning translational studies in humans to bring this discovery into practice so that patients most at risk can receive the best treatment available.”
The research has also revealed many novel targets for ongoing functional studies that the team hope will lead to studies in human hypertensive and diabetic patients.
Source: University of Bristol