The discovery, made by University of Bristol researchers and published in Nature Communications, could revolutionise treatment of the world’s biggest silent killer.
The carotid body — a small nodule (no larger than a rice grain) found on the side of each carotid artery — appears to be a major culprit in the development and regulation of high blood pressure.
Researchers, led by Professor Julian Paton, found that by removing the carotid body connection to the brain in rodents with high blood pressure, blood pressure fell and remained low.
Professor Paton, from Bristol’s School of Physiology and Pharmacology, said: “We knew that these tiny organs behaved differently in conditions of hypertension but had absolutely no idea that they contributed so massively to the generation of high blood pressure; this is really most exciting.”
Normally, the carotid body acts to regulate the amount of oxygen and carbon-dioxide in the blood. They are stimulated when oxygen levels fall in your blood as occurs when you hold your breath. This causes a dramatic increase in breathing and blood pressure until blood oxygen levels are restored. This response comes about through a nervous connection between the carotid body and the brain.
Professor Paton commented: “Despite its small size the carotid body has the highest blood flow of any organ in the body. Its influence on blood pressure likely reflects the priority of protecting the brain with enough blood flow.”
The team’s work on carotid body research started in the late 1990’s and their recent discovery has since led to a human clinical trial at the Bristol Heart Institute of which the results are expected at the end of the year.
Professor Paton added: “This is an extremely proud moment for my research team as it is rare that this type of research can so quickly fuel a human clinical trial. I am delighted that Bristol was chosen as a site for this important trial.”
The carotid body as a novel putative therapeutic target for the treatment of neurogenic hypertension by McBryde, F.D., Abdala, A.P., Hendy, E.B., Pijacka, W., Marvar, P., Moraes, D.J.A., Sobotka, P.A., Paton, J.F.R. (2013). Nature Communications, published 3 September 2013.
High blood pressure
High blood pressure is known as the world’s biggest silent killer because most people can’t “feel” their blood pressure going up. It affects around one in three people and can cause stroke, heart attacks and kidney failure. In England 32 per cent of men and 29 per cent of women have high blood pressure or are being treated for the condition.
The Bristol Heart Institute
The Bristol Heart Institute is made up of over 200 researchers and clinicians, from eight different departments in the University of Bristol, spanning three faculties, and from associated Bristol NHS Trusts. Research income is generated from grants, with the British Heart Foundation being the Institute’s main funder. As well as improving collaboration between scientists and clinicians within the Institute, the aim is to communicate research findings to the public.
BHI CardioNomics Group
Information about the BHI CardioNomics Group is available at www.uhbristol.nhs.uk/patients-and-visitors/your-hospitals/bristol-heart-institute/bhi-cardionomics/