Pubdate: Sun,  1 Oct 2006
Source: San Jose Mercury News (CA)
Copyright: 2006 San Jose Mercury News
Contact:  http://www.mercurynews.com/
Details: http://www.mapinc.org/media/390
Author: Ronald Kotulak

VACCINES AIMED AT HABITS

Research Targets Overeating, Use Of Drugs, Smoking

CHICAGO - Vaccines, the most potent medical weapon ever devised to 
vanquish deadly germs, are now being called on to do something 
totally different and culturally revolutionary -- inoculate people 
against bad habits like overeating, cigarette smoking and drug use.

Whether this new era of vaccine research can subdue many of the poor 
lifestyle choices that are today's biggest threats to health -- 
causing obesity, cancer, heart disease and other problems -- has yet 
to be proved.

But the evidence is promising enough to persuade the federal 
government to put millions of dollars toward finding out whether two 
of the vaccines can end nicotine and cocaine addiction.

The National Institute on Drug Abuse, which has spent $15 million on 
clinical trials for the vaccines and plans to spend more, predicts 
that one of the nicotine vaccines may be available for marketing in 
three years.

Public Health Benefit

"The American Cancer Society has projected that we will have 1 
billion people die from smoking in the world in this century," said 
Frank Vocci, director of medications development for the institute. 
"If you had a vaccine that helped people quit and stay quit, or 
prevent them from smoking, that's where you'd get the greatest public 
health benefit."

Meanwhile, results from a major obesity vaccine trial under way in 
Switzerland are expected this year and company officials are hopeful 
that the vaccine could be ready for use in a few years.

To tamp out deleterious behavior, the new vaccines employ the immune 
system in an innovative way. Instead of building antibodies to 
destroy germs as traditional vaccines do, they construct antibodies 
that lock onto nicotine and cocaine molecules, preventing them from 
reaching the brain.

"What we're seeing is a renaissance in vaccine technology," said Dr. 
Gary Nabel, director of the National Institute of Allergy and 
Infectious Diseases' Vaccine Research Center. "It's only natural that 
when you have a technology that's this powerful it can be applied to 
other medical problems."

Normally, nicotine and cocaine molecules are too small to be seen by 
the immune system. So to make the vaccines, scientists attach these 
molecules to big target proteins, like harmless viruses or bacteria, 
which the immune system can recognize and attack with specialized antibodies.

When the person later smokes a cigarette or takes cocaine, the 
antibodies wrap up and neutralize the molecules before they can 
trigger euphoria and pleasure in the brain. Smokers and cocaine users 
given the vaccines say their pleasure is diminished or they no longer 
get as high, which decreases the desire for the drug.

In the case of the obesity vaccine, antibodies attach to the hunger 
protein called ghrelin, preventing it from reaching the brain and 
stimulating appetite.

Ghrelin, which is secreted by the empty stomach, travels in the 
bloodstream to the brain, where it tells a person to eat. But the 
hormone, discovered in 1999, also has other important roles, such as 
signaling the body to become less active and to store food as fat 
instead of using it for energy production.

The reason it can be so hard to lose weight, researchers believe, is 
that dieting causes large amounts of ghrelin to be produced as the 
body seeks to stimulate eating, slow the metabolism of fat and 
promote fat retention.

Society's Major Ills

To many researchers, the vaccines seem to be a potential answer to 
many of society's major ills -- in the United States there are 50 
million cigarette smokers, 5 million drug addicts, 60 million obese 
adults and 9 million overweight youngsters between the ages of 6 and 19.

Most have one thing in common: They'd like to quit but can't. Nearly 
seven out of 10 smokers, for instance, say they want to stop, but 80 
percent to 90 percent of those who try to quit resume smoking within a year.

Unlike most older vaccines, which tend to confer permanent immunity, 
the new breed of vaccines is reversible, providing immunity against 
nicotine, cocaine or the hunger hormone ghrelin for one to three 
months before booster shots are needed. So far, none of the lifestyle 
vaccines has produced side effects other than some flu-like symptoms 
and soreness at the injection site.

"These vaccines are not going to be a panacea for treating 
everything," said Kim Janda of the Scripps Research Institute, a 
pioneer in developing vaccines for addiction and obesity. "I believe 
they can be helpful. When people are undergoing abstinence for drugs 
of abuse and they have weak moments, if you have a vaccine in place 
it can assist them so they don't spiral down to ground zero."
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MAP posted-by: Elaine