Single dose reversed autism-like symptoms in adult mice within hours
A UCLA Health study in mice found that a single dose of the immune-suppressing drug rapamycin rapidly improved autism-like symptoms in adult offspring of mothers with pregnancy inflammation. However, the effects were temporary, and the drug is not considered a practical treatment for humans.
A study published in Nature Communications by UCLA Health researchers has revealed that inflammation during pregnancy can cause lasting autism-like changes in offspring. In mice, a single dose of rapamycin, an immune-suppressing drug, improved brain function and behavior within about two hours, though the effect was temporary.
The scientists emphasize that rapamycin should not be seen as a practical treatment for humans due to its temporary benefits, potential toxicity with repeated use, and the fact that the study was conducted in mice. However, the rapid response helped identify biological processes that could guide the development of safer, more targeted therapies.
Dr. Harley Kornblum, senior author and director of the UCLA Intellectual and Developmental Disabilities Research Center, stated: "The level of functional normalization achieved over this short time suggests new mechanisms by which possible treatments may act. It suggests the adult brain may be more adaptable than we assumed, even when the underlying structural changes from early development are still there."
Modeling Inflammation During Pregnancy
Researchers exposed pregnant mice to a mild inflammatory stimulus. Their offspring developed persistent brain inflammation, brain overgrowth, excessive mTOR signaling, poorly organized brain network communication, and autism-related behaviors. A single dose of rapamycin improved nearly all measured parameters, including neuronal hyperactivity, seizure susceptibility, sensory sensitivity, repetitive behaviors, and abnormal brain connectivity.
How Rapamycin Worked
The drug rapidly normalized gene expression patterns related to autism, epilepsy, and ion channel function, particularly in excitatory neurons. This suggests that rapamycin restored a healthier balance in neuronal excitability rather than repairing structural differences formed during early development.
Why Rapamycin Is Not the Treatment
Dr. Neil Harris, co-senior author, warned that benefits were short-lived and daily treatment became less effective after several weeks due to tolerance. Combined with potential toxicity and the animal-based nature of the research, rapamycin is unsuitable for widespread human use. However, the findings point toward new therapeutic targets such as sensory circuit neuromodulation or balancing neuronal inhibition and excitation.
