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Can a Cocaine Vaccine Keep Addicts from Using?

Human testing to begin for a new vaccine designed to trigger the immune system to create antibodies against cocaine.
 
 
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This article first appeared in The Fix, which features coverage on addiction and recovery, straight up. 

Imagine that cocaine addiction could be eradicated, poof, with a simple vaccine. At Weill Cornell Medical College, Dr.Ronald G. Crystal, who for years has been working on just such a vaccine, now thinks his team has actually figured out a very clever trick to make that dream a reality.

“The vaccine eats up the cocaine in the blood  like a little Pac-Man before it can reach the brain,” is his pop description of the biology weapon he has fashioned and is about to begin using in human tests after highly successful results with lab animals.

Clearly, any anti-cocaine vaccine that could hold up under further tough testing would permanently alter the landscape of illegal drug abuse in America and might open the door to vaccines for other drugs. According to  The National Institute on Drug Abuse, more than 1.9 million Americans used cocaine in 2009, with more than a million of those classified as cocaine abusers. If Crystal’s new cocaine vaccine is proven effective, the impact of reducing that number by even five percent would be impressive.

But that is a very big doing and requires a number of “big if” hurdle-climbs.

Scientifically, cocaine is a tiny molecule, a  crystalline tropane alkaloid, obtained from the leaves of the South American coca plant. When imbibed, the molecules cross over into the brain and bind to the dopamine transporter, effectively blocking the ferrying of dopamine out of the synapses. Dopamine is the "pleasure" neurotransmitter in the brain. Trapped in the synapses, the result is a massive flooding of the pleasure centers. In short, you get high.

Crystal’s anti-cocaine vaccine combines bits of the common cold virus with (and here is the trick) a particle that mimics the structure of cocaine. When the vaccine is injected, the body "sees" the cold virus and mounts an immune response against both the virus and the cocaine mimic that is hooked to it. Essentially, the immune system is fooled into generating antibodies that will then be activated once real cocaine is imbibed.

“Once immune cells are educated to regard cocaine as the enemy, they produce antibodies against cocaine the moment the drug enters the body," Crystal says.

In Crystal’s animal studies, when the mimic antibodies were extracted and put into test tubes containing cocaine, the antibodies attached themselves to the cocaine molecules and literally gobbled up the cocaine. This caused the cocaine molecules to increase in size to the point where they could not cross over the blood-brain barrier.

In the second stage of Crystal’s research, only 20% of the cocaine was able to cross over the blood-brain barrier and hook onto the dopamine transporters of the vaccinated primates. Moreover, at 20% there were almost no intoxicating effects on the animal subjects. Such a massive drop is the reason why Crystal and his team believe the anti-cocaine vaccine will work in human beings.

"This is a direct demonstration in a large animal…that we can reduce the amount of cocaine that reaches the brain sufficiently so that it is below the threshold by which you get the high,” Crystal told  The Fix.

Crystal’s supposition about cocaine’s specific effect on the brain builds on some  previous human research. Dr. Nora Volkow, the Director of the National Institute on Drug Abuse, used a brain imaging technology called positron emission tomography (PET) to study the brains of long-term cocaine users. Like Crystal, she noted that the intensity of a cocaine-induced high was connected directly to cocaine’s ability to block the dopamine transporter system.

 
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