La Jolla, CA. June 21, 2004—Scientists at The Scripps Research Institute have designed a potentially valuable tool for treating cocaine addiction by creating a modified "phage" virus that soaks up the drug inside the brain.
They coated the virus with an antibody that binds to molecules of cocaine and helps to clear the drug from the brain, which could suppress the positive reinforcing aspects of the drug by eliminating the cocaine high.
"Typically one would think of a virus as a bad entity," says principal investigator Kim D. Janda, Ph.D., who holds the Ely R. Callaway, Jr. Chair in Chemistry and is an investigator in The Skaggs Institute for Chemical Biology at Scripps Research. "But we are taking advantage of a property it has—the ability to get into the central nervous system."
The structure and design of the virus and its effect in rodent models are described in an article that will be published in an upcoming issue of the Proceedings of the National Academy of Sciences.
Note this virus is not acting like a typical vaccine. It is not being injected in order to cause an immune response by the body against cocaine. The actual virus contains the antibodies that bind to the cocaine.
The economic and human toll for cocaine is rather higher.
Americans spend more on cocaine, a chemical extracted from the leaf of the Erythroxylaceae coca plant, than on all other illegal drugs combined, says a White House Office of National Drug Control Policy study that came out in the mid-1990s. The study estimates that $38 billion was spent on cocaine in the years 1988 to 1995 alone.
Cocaine's secondary costs to society due to cocaine treatment and prevention programs, emergency room visits and other healthcare costs, lost job productivity, lost earnings, cocaine-related crime, and social welfare are estimated to be in the billions of dollars annually—not to mention the drug's human toll. According to the National Institute on Drug Abuse (NIDA), about 1.7 million people regularly use cocaine in the United States—a population larger than that of the city of Philadelphia—and cocaine is the leading cause of heart attacks and strokes for people under 35.
Sounds like this could be delivered as a nasal spray.
A few years ago, Janda and his graduate students Rocio Carrera and Gunnar Kaufmann decided they wanted to target the cocaine antibodies into the brain. That's when they set out to create a new form of virus. This was done with collaborators Jenny Mee and Michael Meijler in the Department of Chemistry and Professor George Koob in the Department of Neuropharmacology and the Pearson Center For Alcoholism And Addiction Research at Scripps Research.
The reserachers used filamentous phage—a type of virus that infects bacteria—for the study. They inserted DNA encoding an antibody that binds cocaine into the phage's genetic code. When the modified phage were grown, they had hundreds of these antibodies displayed on their surfaces.
Phage particles, like many types of viruses, have the ability to enter the brain through the internasal passageway. Janda, Carrera, and Kaufmann used this ability to deliver their antibody into the central nervous system. The current study demonstrates the ability of the antibody/phage to reduce one effect of cocaine in rodent models (increased locomotion).
She hopes that addicts who want to quit could eventually be given the treatment. “It’s for weak moments,” she says. The virus lingers in the brain for around two weeks, so although they might relapse once, the absence of any euphoric feeling would then discourage them from taking it again.
Lead researcher Professor Kim Janda told BBC News Online: "This would be used in conjunction with abstinence programmes and maybe in conjunction with other vaccines that only treat the peripheral sites - like a one-two punch."
The need to take this treatment once every week or two is problematic. Many addicts who are trying to kick who only take cocaine at a weak moment will be willing to take boosters. But some will decide at some point that they want to get back on the coke and stop taking the nasal spray booster and then just wait a couple of weeks before using again. Though boosters delivered in front of a parole officer or doctor could be compelled by court orders in some cases.
We need better methods to control addiction. A lot of addicts want to kick their habits but the compulsion to use can be very strong. An ideal treatment, however, would stop the craving and even repair or replace damaged and destroyed neurons. Plus, given that some people are more prone to addiction an ideal treatment would change their brains in ways that make them permanently less likely to get addicted again.
|Share |||Randall Parker, 2004 June 23 10:30 AM|