Autism Spectrum Disorder (ASD), commonly known simply as Autism, comprises a range of neurodevelopmental disorders, with varying degrees of symptoms such as repetitive behaviors, impaired communications, and poor social engagement. According to the Centers for Disease Control and Prevention, one in every 68 children across the globe, or 70 million people, have some form of ASD.
Genes and environment have been found to jointly cause ASD. Researchers have tried to lay out the disorder’s molecular mechanisms, but much remains to be resolved. Today, medical, educational, and behavioral treatments have been developed to better integrate ASD patients into society. Each individual displays a different degree of need for the available treatments due to the heterogeneous nature of possible symptoms. In May 2017, Professor Nahum Sonenberg of the McGill Department of Biochemistry and his research associate, Ilse Gantois, co-authored a paper in Nature Medicine discussing the possibility of future treatments for the symptoms of ASD. The study shows that metformin, a drug commonly used to treat diabetes, could help symptoms of an autism-like disorder—Fragile X Syndrome.
“Fragile X Syndrome (FXS) is a genetic disease caused by defects in the Fragile X Mental Retardation 1 gene (FMR1), which triggers excess production of protein in the brain, as well as dysregulated connections between neurons and changes in behaviour,” A McGill Newsroom article explains. “The condition leads to impairments in speech and language, behaviour, and social interaction. It affects about 1 in 5,000 boys and 1 in 6,000 girls and is often co-diagnosed with autism, anxiety disorders and seizures.”
Mice used in the study were bred to show similar behaviors to those of Autism patients, such as impaired social interaction and repetitive activities. The researchers used the mice because are a reliable model to emulate ASD in a laboratory setting. Gantois said the Fragile X mice were administered with metformin for 10 days. The injections eventually reduced “excessive grooming and impaired social interaction,” symptoms which are equivalent to repetitive behaviour and impaired social functioning in humans with ASD.
“Our data show that metformin, the most widely used FDA-approved antidiabetic drug, corrects most phenotypic [or observable characteristics as a result of an individual’s genes] deficits in the adult FXS mouse model,” said Gantois, the primary author of the paper. “[Metformin] could be repurposed for the treatment of FXS in the clinic.”
Furthermore, nerve cells are misshaped in FXS mice. Metformin also “reversed the defects in dendritic spines and in synaptic transmission”—meaning that it repaired the nerve damage. Therefore, metformin is a potential treatment for Fragile X and for Autism as it reduces their defects.
Metformin has amazed scientists for its capacity to relieve a mosaic of disparate diseases such as type 2 diabetes, cancer, cardiovascular diseases and age-related neurological diseases.
“We want to study if metformin is also able to reverse a variety of behavioural and morphological deficits in other mouse models of ASD,” said Gantois, laying out future routes for ASD research. “These findings may lead to beneficial effects of metformin for other types of autism.”
According to Gantois, the lab’s next investigative goal is “to further study the mechanism of how metformin exactly works in the brain, what molecules metformin interacts with and what cellular functions are affected.”
