New blood pressure treatment possible
Tue Sep 06 2016 12:00:00 GMT+1200 (New Zealand Standard Time)
New blood pressure treatment possible
06 September 2016
Dr Fiona McBryde working in the lab.
For the first time in more than 15 years, a new drug treatment for high blood pressure is in development.
An international collaboration involving researchers at the University of Auckland has helped identify a potential new way of treating high blood pressure (hypertension), by targeting a new nerve receptor pathway.
The research was published today in the online edition of Nature Medicine.
The study was led by the University of Auckland’s Honorary Professor Julian Paton, and involved University research fellow Dr Fiona McBryde who made key contributions to the research.
“More than half of all patients prescribed medication for high blood pressure do not have their blood pressure under control,” says Dr McBryde. “This may be because their high blood pressure is treatment resistant, when despite diligently taking all of their pills their blood pressure remains stubbornly high.”
“Alternatively, side effects may put them off taking their medications,” she says. “This is a particular problem with high blood pressure, because although your risk of conditions like heart attacks and stroke is greatly increased, high blood pressure itself is largely symptom-free - until the patient starts taking drugs to control it.”
“To improve things for patients, what is really needed are more treatment options,” says Dr McBryde. “One major problem is that there are no truly novel drugs to treat high blood pressure and many of the newer drugs overlap pathways already targeted by older medications.”
“The exciting feature of our research is that our drug hits a receptor pathway that has never previously been exploited for high blood pressure,” she says. “This is good news for treatment resistant patients who are not responding to existing medication, and also may help patients suffering from side effects by giving a true alternative to their treatment options.”
Globally, one in three adults has high blood pressure. A 10 mmHg rise in blood pressure >115/75 mmHg doubles the risk of death from cardiovascular disease in adults aged over 40 years, and each 2 mmHg rise in blood pressure increases the risk of stroke by 10 percent.
Instead of treating high blood pressure by targeting the functions within end organs such as the heart, kidneys and vasculature, this new approach aims to reduce nervous system activity from a sensory organ, the carotid body, that when activated can cause blood pressure to rise uncontrollably.
“In healthy individuals, the carotid bodies have very low levels of activity, and act as guardians to protect the supply of blood and oxygen to the brain” says Professor Paton. “We have discovered that these tiny organs become inappropriately active in conditions of hypertension, generating a signal to the brain which drives an increase in blood pressure.”
Such a treatment may offer superiority over existing medications by lowering blood pressure directly at a common source driving the development of hypertension, he says.
“Beneficial outcomes may also extend to other cardio-metabolic disorders, such as heart failure and sleep apnoea in which the carotid bodies are known to be sensitized,” says Dr McBryde.
The research is supported by the Royal Society Newton alumni scheme in conjunction with Afferent Pharmaceuticals, a subsidiary of Merck. Professor Paton is also a Professor of Physiology at the University of Bristol in the United Kingdom.
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