Neuroconductual alterations in children with autism associated with levels of plasma ammonia and urea hydrolyzing bacteria

Abstract

Introduction: Autism is a neurodevelopmental disorder; its etiology is not yet well defined. Several theories indicating a close relationship between intestinal dysbiosis and its metabolites have emerged, especially those related with the presence of ammonium and neurobehavioral alterations in patients with autism spectrum disorder (ASD). Objectives: Relate plasmatic ammonium levels with bacterial overgrowth, to find out if there is an association with antimicrobials and anticonvulsants intake, electroencephalogram changes, and neurobehavioral and gastrointestinal alterations in patients with ASD. Methods: Intestinal dysbiosis and plasmatic ammonium levels were evaluated in an intentional group of 63 children with ASD and in 35 healty children as a control group. A survey to collect epidemiological, clinical and neurobehavioral data was applied. Results: 61% of the patients with intestinal dysbiosis showed increases in Proteobacteria phylum, of which 40% were urea hydrolyzing bacteria. The plasmatic ammonium levels were significantly associated with urea hydrolyzing bacteria in 43% of children with ASD. Antimicrobials intake were associated with levels of plasmatic ammonium levels and urea hydrolyzing bacteria above the average in patients with ASD. Most of the neurobehavioral alterations evaluated in these patients were associated with plasmatic ammonium levels. Conclusions: In this study, the neurobehavioral alterations evaluated in patients with ASD were related to the increase in plasmatic ammonium levels produced by urea hydrolyzing bacteria causing intestinal dysbiosis.