March 09, 2008

Novel Use of Vaccines in Controlling Hypertension and Drug Dependance

Vaccines have important roles in combating infections, viral or bacterial. Gone are the days when we used to associate them for preventing viral or bacterial infectious diseases only; before the actual exposure to the disease-causing-agent happened. That means, we used to give them in anticipation of an outbreak. They are 'also' given as Post Exposure Prophylaxis (PEP, where the person is receiving the vaccine after an exposure (such as dog-bite, in the case of rabies) in rabies, measles, poliomyelitis, Haemophilus influenzae, tetanus, hepatitis, varicella zoster (chickenpox) and many others.

Now, we are beginning to hear about vaccination against cocaine abuse (TA-CD vaccine), tobacco abuse (NicVAX) and many other diverse fields in which vaccines were not, usually, associated with. Recently, scientists suggested that we may not have to bother about medicating ourselves with antihypertensive drugs (drugs that lower blood pressure) for the control of blood pressure anymore. One or more shot of a vaccine directed against angiotensinII may in future, keep the B.P. under control. Thus, vaccination is effective against drug dependence as well as in the regulation of high blood pressure.

schematic representation of the renin angiotensin alderosterone systemAngiotensin 2 is a potent vasoconstrictor, which is produced from angiotensinogen, when the enzyme Angiotensin Converting Enzyme (ACE) acts upon it (angiotensinogen). So far, scientists focused on:
  • inhibiting ACEs (some ACE inhibitors are: Lisinopril, Ramipril, Captopril, Perindopril) blocking angiotensin receptors (Losartan, Irbesartan,Telmisartan)
  • blocking endothelin receptors (Bosentan, a drug which is pretty effective in pulmonary hypertension. Endothelin being a potent vasoconstrictor raises blood pressure). ACEIs (ACE inhibitors) gave survival advantages, in addition to the inhibition of cardiac remodeling.
  • Beta blockers (e.g. metoprolol, bisoprolol etc), Calcium channel blockers (amlodipine) and other drugs. But novel approaches are emerging.
Now, researchers at the Swiss biotechnology firm Cytos have shown that a vaccine against angiotensin 2, controlled hypertension with fewer side effects. Apart from a mild flu like symptom, the adverse effects were few and far between. The BP lowering effect were most pronounced in the early morning hours, when there is a natural surge in BP. The vaccine (CYT006-AngQb), by countering the pressure-determining renin angiotensin system, would thus keep the person normotensive.

As long as there is no autoimmune reaction, and the kidney is not burdened with immune complexes, the novel therapeutic approach is likely to succeed.

Last modified: July 13, 2009
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1 comment:

Kimberly said...

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