Early risperidone exposure impairs cognitive function by perturbation of the gut microbiome and bile...

Second-generation antipsychotics (SGAs) are increasingly being utilized in children and adolescents. Risperidone, one of the most commonly prescribed SGAs in this population, has been found to adversely affect cognitive function; however, limited knowledge exists regarding the impact of risperidone on the gut microbiome-brain axis. We hypothesized that the cognitive impairment induced by risperidone is mediated by alterations in the gut microbiome and its metabolites.

In this study, we found that early-life risperidone exposure impaired cognition in mice, including deficits in behavior tests and hippocampal dendritic architecture. The risperidone-exposed mice also exhibited gut microbiota dysbiosis along with damage to the intestinal barrier. Fecal microbiota transplantation (FMT) from treated donors to recipients demonstrated the causal role of the gut microbiome in risperidone-induced cognitive deficits. Of note, risperidone increased the abundance of species Escherichia coli, Eggerthella lenta, Ruminococcus gnavus, Clostridium perfringens, Clostridium difficile, and Blautia hydrogenotrophica. These altered species are identified to encode 7α-HSDH, 3β/α-HSDH, TyrB, and porA, the key enzymes in secondary bile acid metabolism and tyrosine metabolism. Furthermore, a significant reduction in tauroursodeoxycholic acid (TUDCA, the metabolite of bile acid metabolism) and accumulation of p-cresol (the metabolite of tyrosine metabolism) were observed in the brains of mice exposed to risperidone. Mechanically, TUDCA prevented cognitive impairment and endoplasmic reticulum (ER) stress in the hippocampus induced by risperidone, while p-cresol induced neuronal ER stress. Knockout of protein tyrosine phosphatase 1B (PTP1B, ER stress-associated protein) in neurons ameliorated cognitive impairment and neurological damage induced by risperidone.

This study, for the first time, reveals that early risperidone exposure induces gut microbiome dysbiosis and disturbs the bile acids/tyrosine-PTP1B axis to impair cognitive function. These findings alert the risk of gut and neurological side effects of SGAs treatment and highlight that it is crucial to maintain gut homeostasis during the brain developmental phases of children and adolescents with SGAs exposure. Video Abstract.