June 29, 2012
Vaccine for Nicotine Addiction?
(Ivanhoe Newswire) - An estimated 46 million Americans are current smokers, and approximately 70% of them wish they had never smoked, and want to quit. While it is the 4,000 chemicals within the burning cigarette that causes the health problems associated with smoking, it is the nicotine within the tobacco that keeps the smoker hooked.
Researchers at Weill Cornell Medical College have developed and successfully tested in mice an innovative vaccine to treat nicotine addiction. The scientists describe how a single dose of their novel vaccine protects mice, over their lifetime, against nicotine addiction.
The vaccine is designed to use the animal's liver as a factory to continuously produce antibodies that gobble up nicotine the moment it enters the bloodstream, preventing the chemical from reaching the brain and even the heart.
The study's lead investigator, Dr. Ronald G. Crystal, chairman and professor of Genetic Medicine at Weill Cornell Medical College was quoted as saying, "As far as we can see, the best way to treat chronic nicotine addiction from smoking is to have these Pac man-like antibodies on patrol, clearing the blood as needed before nicotine can have any biological effect."
"Our vaccine allows the body to make its own monoclonal antibodies against nicotine, and in that way, develop a workable immunity." There are, in general, two kinds of vaccines. One is an active vaccine, like those used to protect humans against polio, the mumps, and so on, and a passive vaccine, which delivers readymade antibodies to elicit an immune response. The Weill Cornell research team developed a new, third kind, a genetic vaccine.
Previously tested nicotine vaccines have failed in clinical trials because they all directly deliver nicotine antibodies, which only last a few weeks and require repeated, expensive injections, Dr. Crystal explained. Plus, this kind of impractical, passive vaccine has had inconsistent results, perhaps because the dose needed may be different for each person, especially if they start smoking again, he added. Studies show that between 70 and 80 percent of smokers who try to quit light up again within six months.
The researchers are preparing to test the novel nicotine vaccine in rats and then in primates, steps needed before it can be tested ultimately in humans. Dr. Crystal explained that, if successful, such a vaccine would best be used in smokers who are committed to quitting. "They will know if they start smoking again, they will receive no pleasure from it due to the nicotine vaccine, and that can help them kick the habit," he was quoted as saying.
He adds that it might be possible, given the complete safety of the vaccine, to use it to preempt nicotine addiction in individuals who have never smoked, in the same way that vaccines are used now to prevent a number of disease-producing infections. "Just as parents decide to give their children an HPV vaccine, they might decide to use a nicotine vaccine. But that is only theoretically an option at this point," he concluded. "We would of course have to weight benefit versus risk, and it would take years of studies to establish such a threshold."
SOURCE: The Journal Science Translational Medicine, June 2012