On May 12, 2007, Protherics, a pharmaceutical company with offices in Brentwood, Tennessee and London, England, announced that their new vaccine for the treatment of high blood pressure is showing promising results in clinical trials.(1)

Blood pressure regulation within the body is a complex system. The primary control mechanism is through the “renin-angiotensin” system, a cascade of hormones produced in the kidneys. When the enzyme renin is released from the kidneys, it attaches to angiotensinin, a protein found in the blood. Once attached, angiotensinin is converted to an intermediate compound called angiotensin I (AT1). This molecule is further converted to the active form called angiotensin II (AT2). When this cascade is overactive, hypertension (high blood pressure) is the result.

AT2 can powerfully constrict blood vessels during times of stress, shifting the blood flow from the extremities to vital organs. Protherics vaccine, called Angiotensin Therapeutic Vaccine, is designed to induce antibodies that will neutralize AT1. Without AT1, there can be no AT2. The planned result is normal blood pressure.

On first blush, the idea of a vaccine to control high blood pressure sounds like a good idea. Many patients fail to take their prescribed medicines, often because they do not like the side effects or because they can’t afford the drugs. As a result, it is estimated that nearly 70% patients with hypertension suffer from complications, including the possibility of a heart attack or a stroke.

For Protherics, the positive result from its clinical trial has potentially enormous economic ramifications. Recent data shows that the market for high blood pressure medication is worth approximately US$36 billion per annum.(2) The Company hopes that a vaccine given every few months will improve control of blood mild to moderate pressure by increasing patient compliance. Protherics is developing an improved formulation that will contain a “novel vaccine adjuvant” and will continue its human trials throughout 2007. If all goes well, Protherics plans to start licensing the vaccine to manufacturing partners after the new trials have been completed.

But before rushing to the doctor, the consequences of manipulating the AT1-AT2 system by a vaccine need to be considered. Within the past two decades, a great deal has been learned about the renin-angiotensin system in other parts of the body. It has been discovered that the brain also produces angiotension peptides and depends on these molecules for high function. AT1 and AT2 in the brain are responsible for the regulation of blood flow to the brain tissue, cognition, learning, behavior, memory and regulation of emotional responses.(3)(4)(5) It is not known if the vaccine will cross the blood-brain barrier and cause dysfunction of the brain renin-angiotensin system.

The skin is also directly affected by angiotensin peptides. It has been clearly demonstrated that AT2 plays an important role in wound healing.(6) A vaccine that blocks the formation of AT2 may seriously impact the ability for the skin to repair and heal after an injury. There are simple, natural ways to lower your blood pressure. Start by maintaining your ideal body weight, exercising regularly, getting plenty of sleep and keeping well-hydrated. Be very cautious before agreeing to be vaccinated for blood pressure control.

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