By Susanne Rust
Considered one of the most widely abused and addictive recreational drugs, researchers may be one step closer to knocking down the destructive pull of methamphetamine.
A team of scientists at the Scripps Research Institute in La Jolla has developed a vaccine that appears to protect against meth intoxication in laboratory animals.
The next step will be to see if it works in people, too.
"This is an early-stage study, but its results are comparable to those for other drug vaccines that have gone to clinical trials," said Michael Taffe, a Scripps researcher with the institute's Committee on the Neurobiology of Addictive Disorders.
The study was released online last week in the journal Biological Psychiatry.
Methamphetamine has become one of the most common and destructive recreational drugs in the country. In the United States, government data estimate that there are currently more than 430,000 users, with more than 41,000 new users this year. And in California, meth accounts for more primary drug abuse treatment admission - 26 percent - than any other drug, including marijuana (21 percent) and alcohol (12 percent). The state's Central Valley is considered to be the hub of nation's meth distribution network.
Earlier this spring, one of the largest U.S. methamphetamine drug busts took place in San Jose, where more than 750 pounds of the drug was seized, with a street value of more than $34 million.
The drug, also known as speed or crank, can cause psychosis, and its stimulatory effects are considered 50 times stronger than cocaine, keeping people awake for days.
Researchers and health officials are actively looking for ways to reduce dependency and keep the drugs out of people's hands. One idea that has been pursued for years is to design a vaccine that could attack the drug as it gets into the body and keep it from going into the brain and the nervous system.
It's an approach that has also been used for other addictions, with vaccines for cocaine and nicotine currently in development.
In pursuit of a similar system for methamphetamine, Taffe and his colleagues at Scripps developed several compounds that they thought might work and gave them to rats to see what would happen.
One of those compounds, MH6, seemed to have an effect.
Rats "high" on meth not only have extremely high levels of energy, but their body temperature increases significantly as well. The compound MH6 blocked those two effects, leading the scientists to believe that the vaccine was preventing methamphetamine from reaching the nervous system.
The researchers also found a healthy antibody response in the rats given MH6, indicating the body was working to fight the drug.
"These are encouraging results that we'd like to follow up with further animal tests, and, we hope, with clinical tests in humans some day," said Michelle Miller, a co-author of the paper and a member of Taffe's lab.
Taffe said while the results are promising, the research is still in its infancy. The vaccine is not as long lasting as the researchers would like - the effects last weeks, not years - and they still have other questions that need to be answered.
Such as, will rats stop craving the drug if on the vaccine?
"It's looking promising," said Taffe, "but we're still pretty early on in the process."