Researchers at the University of California, Los Angeles, have identified a potential avenue for easing autism symptoms, discovering that a single dose of rapamycin, a drug approved by the FDA and favored by longevity enthusiasts, may temporarily reverse such symptoms in adult mice. The study, published in Nature Communications, found that administering the drug to mice exhibiting autism-like behaviors led to a significant reduction in repetitive actions within two hours.
Rapamycin, originally approved in 1999 to prevent organ transplant rejection, has gained attention in recent years for its purported anti-aging effects. While some research suggests it can extend lifespan in mice, other studies have noted drawbacks in humans, such as diminishing the benefits of exercise.
The UCLA researchers administered five milligrams of rapamycin in a solution to adult mice with autism. They observed that within two hours, the mice displayed fewer repetitive behaviors, like excessive grooming or running in circles. This effect lasted approximately 72 hours before the mice returned to their previous behavioral patterns. Daily injections of the drug for five weeks did not appear to sustain the effect, suggesting it does not rewire the brain.
Instead, scientists hypothesize that rapamycin may calm dysfunctional or misfiring neurons, which are believed to drive some autism-associated symptoms. Tests indicated that mice treated with rapamycin exhibited less abnormal brain activity.
Dr. Harley Kornblum, a neuroscientist who led the research, stated that the rapid functional normalization observed suggests that adult brains might be more adaptable than previously thought, even when structural changes from early development persist. This finding could reshape approaches to treating autism-associated symptoms, potentially addressing features of autism without needing to correct underlying structural differences.
Autism spectrum disorder is now defined by a range of symptoms, including repetitive words or behaviors, difficulty with routine variation, and challenges in social situations. An estimated five million American adults and one in 31 children are affected by the condition. Current treatments typically involve speech and language therapy, and sometimes medications for anxiety and depression, to help manage atypical behaviors, as there is no known cure for autism.
However, the study authors and researchers stressed that this research was conducted solely on mice and does not indicate rapamycin as a viable human treatment. They noted that repeated doses could lead to toxicity and that the observed effects were temporary. The researchers stated that their findings highlight new therapeutic targets for the development of future treatments rather than recommending rapamycin itself.
Concerns about rapamycin's side effects are significant. Common adverse effects include high blood pressure, kidney injury, increased susceptibility to infections, and swelling. More serious risks can involve blood clotting problems, lung issues, and slow wound healing. For example, biohacker Bryan Johnson, who had been taking rapamycin for five years to attempt to extend his lifespan, reportedly stopped due to perceived risks outweighing benefits, citing issues like skin infections and a higher resting heart rate.
Scientists are continuing to explore other potential treatments for autism, including leucovorin, a form of vitamin B, which has gained attention from public figures. Research is also ongoing into various drugs believed to help ease the condition.