Treating high blood pressure could one day be as simple as going for a vaccination.
A new study published in The Lancet finds that immunization against a hormone called angiotensin II appears to lower the blood pressure of patients with hypertension and could eventually replace traditional medications for the common, and sometimes life-threatening, condition.
People with high blood pressure are typically treated with ACE inhibitors, which stands for angiotensin-converting enzyme inhibitors, as well as with angiotensin receptor blockers (ARBs).
While the drugs are effective, patients often stop taking them because they don't like their side effects, such as dizziness or headache, or think they don't need them because they are not noticing the symptoms of their high blood pressure.
In fact, it's estimated that only about a third of patients with hypertension in the U.S. have their blood pressure under control.
Immunization to suppress the action of angiotensin could simplify treatment, since it would require only a few injections a year, rather than daily pill-popping. But previous attempts to immunize against angiotensin I have shown poor results.
In this study, researchers had better success by targeting angiotensin II, a potent blood chemical that causes the muscles surrounding blood vessels to contract, thereby narrowing the vessels and causing high blood pressure.
Dr. Martin Bachmann of Cytos Biotechnology in Schlieren, Switzerland, tested the vaccine on 72 patients with mild-to-moderate hypertension. The patients received either 100 micrograms of the vaccine; 300 micrograms of the vaccine (24 patients); or placebo.
Their blood pressures were then taken 14 weeks later.
The researchers found that the 300 microgram group were able to lower their average daytime blood pressure by -9.0/-4.0 mm Hg compared with placebo. They also saw their early morning blood-pressure surge drop -25/-13 mm Hg compared with placebo.
"The drop in blood pressure was especially pronounced in the early morning, when the renin-angiotensin-aldosterone system is most active and when most cardiovascular events occur," the authors note.
In an accompanying editorial, Dr Ola Samuelsson and Dr Han Herlitz of the department of nephrology at Sahgrenska University Hospital in Gothenberg, Sweden, say: "The results of this new biotherapy for hypertension are intriguing and promising, and vaccination for hypertension may turn out to be very useful in many patients."
