Mar. 23 --
MONDAY, June 25 (HealthDay News) -- Prolonged use of methamphetamine can lead to a variety of cardiovascular problems, including arrhythmias, intracranial bleeding, and congestive heart failure, a new study found.
In experiments with rats, researchers identified the way the drug triggers the cardiovascular problems often seen in people who are addicted to it.
"Methamphetamine can cause a number of medical complications that haven't been recognized before," said lead researcher Kim D. Janda, a professor of chemistry at the Scripps Research Institute, in La Jolla, Calif. "Not only is it addictive, but it can cause a number of complications from cardiovascular to inflammation. It's a real dirty drug."
Long-term use of methamphetamine can cause an aberrant chemical reaction of amphetamine and sugar structures that change proteins to cause both an antibody and inflammation response, Janda said. "This reaction can cause both heart and blood vessel damage," he added.
This finding may also explain why methamphetamine users need to increase the drug's dose to gain the same effect, Janda said. "The antibody response can remove the methamphetamine from cells, so they need to take more," he said.
Most research on methamphetamine has focused on the effects of the drug on the brain, said study co-author Tobin J. Dickerson, an assistant professor of chemistry, also at the Scripps Research Institute. "But there are things that happen to other parts of your body," he said.
The study authors found that methamphetamine reacts with proteins in the body, creating compounds called advanced glycation endproducts (AGE). These compounds have been tied to a variety of diseases, including Alzheimer's and diabetes.
In experiments with rats, the researchers found that methamphetamine did react with the proteins when the rodents self-administered the drug. In addition, these methamphetamine-induced AGE products disrupted the normal function of these proteins.
For example, in the circulatory system, AGEs formed deposits on artery walls, causing inflammation resulting in damage to the artery. Janda thinks that the same mechanism at work in rats in the study is also present in humans.
This finding could lead to ways to prevent this effect of methamphetamine abuse in people, Dickerson said. "If you could prevent this mechanism, you could prevent the vascular damage," he said. Research along this line is being done with diabetes, in which the same mechanism is responsible for blood vessel damage, he added.
The study is published in the June 25-29 issue of the Proceedings of the National Academy of Sciences.
Dr. Khung-Keong Yeo, a clinical fellow at the University of California, Davis, thinks the new study may offer an explanation for the cardiovascular effects seen with methamphetamine use.
"Specific to my interest in the cardiovascular effects of methamphetamine, I think the paper suggests a very interesting hypothesis-generating mechanism of action for the cardiovascular effects of methamphetamines," Yeo said.
Yeo said further experiments should be done to see if the animals actually develop heart problems like the ones seen in methamphetamine addicts. "It would be interesting to see the effects on the animal hearts," he said. "For example, if the rise in pro-inflammatory proteins would result in cardiomyopathy," which is inflammation of the heart muscle.
For more on methamphetamine, visit the U.S. National Institute on Drug Abuse.
SOURCES: Kim D. Janda, Ph.D., professor of chemistry, Tobin J. Dickerson, Ph.D., assistant professor of chemistry, both Scripps Research Institute, La Jolla, Calif.; Khung-Keong Yeo, M.D, clinical fellow, University of California, Davis; June 25-29, 2007, Proceedings of the National Academy of Sciences