A clinical trial of a vaccine to combat high blood pressure yielding promising results.
The search for vaccines against infectious diseases has become the rage. These include high blood pressure. The first human clinical trial of a vaccine directed against one of the proteins responsible for this physiological disorder, angiotensin II, has just been published in The Lancet by the team of Martin Bachmann (Cytos Biotechnlogy, Switzerland).

In fact, if there are new generation drugs very effective against the enzyme for
the conversion of an-giotensine or capable of blocking this receptor molecule vital in controlling blood pressure, everything is not so simple in the real world. As against this silent killer, which causes no symptoms, the patient must take capsules and tablets every day without feeling any immediate benefit.

And that is where the shoe pinches, Swiss researchers argue. "Only one third of hypertensive patients in the United States have blood pressure well controlled." This means, because adherence to treatment ordered by the doctor is low. In addition, patients complain more side effects due to the medication they have no symptoms related to hypertension. The search for a vaccine antihypertensive did not yesterday! That Irvine Page, American physiologist of the Cleveland Clinic who, in 1958, had first raised the possibility of acting on small molecules to control blood pressure through a vaccine. Historically, said Professor Joel Menard (former Director General of Health) Immunization began with the simple injection of a slightly modified version of renin (also involved in controlling hypertension, Ed) to generate antibodies in the purpose of lowering blood pressure.

The target: the angiotensin II
The first publications date from the 1950s also. Closer to home, a preclinical test of Cytos vaccine, produced in 2007 on rats and mice (Journal of Hypertension) showed that it is immunogenic (ie the animal developed antibodies) were found safe and effective. The immunization target is chosen angiotensin II: a protein hormone that actually causes intense constriction of blood vessels, and therefore arterial hypertension and an adrenal gland stimulation and increased secretion of aldosterone, which also increases the pressure arteries.

In the study published last week by The Lancet, 72 patients with hypertension, low (but real) to moderate were randomly divided into three groups to receive three injections of 100 or 300 micrograms of the vaccine, or an equivalent dose of placebo over a period of one year. Blood pressure was measured during the 24 hours preceding the vaccine and then 14 weeks later. The researchers found a significant reduction in daytime blood pressure by almost 9 mm Hg (systolic pressure of a normal adult is 130 mm) in the group receiving the high dose vaccine.

Should we continue to make progress in this area? "I feel that our knowledge is too low, estimated in 2007 Professor Menard, for good measure the risk / benefit ratio of such a vaccine," then a daily oral treatment available, it is safe and well tolerated. Dr. Menard knows whereof he speaks: in 1985 he had tested this type of vaccination in the marmoset and the animal had developed an autoimmune disease of the kidney, which led him to stop all testing. A vaccine against hypertension is also urgently need a vaccine against HIV or cancer? "Even if we can draw lessons from a manipulation of the immune system, the safety remains a priority," says Joel Menard.

He nevertheless stressed that this discovery opens a new door that could also have impact on other chronic diseases such as diabetes or atherosclerosis, which require daily medication.


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