May 3, 2010
An antibiotic called rapamycin, currently used to suppress the immune system in people who receive organ transplants, is showing promise in the fight against Alzheimer’s disease. The drug restored memory and thinking skills in mice that had been genetically bred to develop a form of Alzheimer’s disease. While it’s a long way from mice to people, the findings offer intriguing evidence that rapamycin may have benefits for brain health in humans.
Researchers from The University of Texas Health Science Center at San Antonio found that rapamycin reversed Alzheimer’s-like memory problems in the animals. The drug, originally isolated from Easter Island soil samples some 40 years ago, also reduced the number of brain lesions in the mice. The findings were published in The Journal of Biological Chemistry.
"Our findings may have a profound clinical implication," said study author Dr. Salvatore Oddo of the university's Barshop Institute for Longevity and Aging Studies. "Because rapamycin is a U.S. Food and Drug Administration-approved drug, a clinical trial using it as an anti-Alzheimer's disease therapy could be started fairly quickly."
Last year, scientists reported that the drug had the remarkable property of extending life in mice, even when the mice were nearly 2 years old, equivalent to about age 60 in people. Nobody is sure how the drug produces this life-extending effect.
In the current study, 6-month-old mice ate chow containing rapamycin for 10 weeks. The specially bred mice, equivalent in age to adults in their 20s and 30s, were already showing signs of Alzheimer’s-like memory and mental decline.
The mice were then tested in an experimental setting called the Morris water maze, a miniature swimming pool used to assess learning and memory in rodents. The animals showed improvements in memory and thinking skills. Analysis of the rodents’ brains also showed they contained fewer Alzheimer’s-like lesions.
"While it remains to be determined whether our results obtained in mice could be translated in people, we are very excited as these findings may lead to a new therapeutic intervention to treat Alzheimer's," Dr. Oddo said.
Much more testing is needed to see if the antibiotic is safe and effective for fighting Alzheimer’s in people. Earlier studies have shown, for example, that the drug can have serious side effects. Because rapamycin suppresses the immune system, those taking it are susceptible to serious infections. It has also altered levels of fats in the blood, which may raise the risk of heart disease.
Source: University of Texas Health Science Center at San Antonio (2010, February 24). "Rapamycin rescues learning, memory in Alzheimer's mouse model." ScienceDaily. Retrieved February 25, 2010, www.sciencedaily.com.