GUT-BRAIN AXIS AND MICROBIOTA IN PEDIATRIC NEUROLOGY: IMPLICATIONS FOR AUTISM, ADHD, AND CHILDHOOD EPILEPSY

Abstract

The microbiota-gut-brain axis represents a bidirectional communication network that integrates neural, immune, endocrine, and metabolic mechanisms, drawing increasing interest for its potential role in the development and modulation of pediatric neurological conditions. During childhood, a period marked by the simultaneous maturation of gut microbiota and the central nervous system, changes in the composition and metabolic activity of microbial communities have been investigated in connection with neurodevelopmental disorders and neurological disease. This review aimed to examine the implications of the microbiota-gut-brain axis for autism spectrum disorder, attention-deficit/hyperactivity disorder, and childhood epilepsy, taking into account pathophysiological mechanisms, clinical manifestations, and potential therapeutic perspectives. A narrative literature review was carried out, guided by a question structured according to the PICo strategy and by a search for studies related to gut microbiota and the three pediatric neurological conditions under investigation. The available evidence points to changes in the diversity, composition, and function of microbiota in subgroups of children with these conditions, although the patterns identified remain inconsistent. Among the mechanisms proposed are changes in intestinal permeability, immune-inflammatory signaling, production of microbial metabolites, modulation of neurotransmitters, and vagal nerve communication. In autism and ADHD, these mechanisms have mainly been linked to behavioral, metabolic, and gastrointestinal manifestations, while in epilepsy the microbiota's possible involvement in neuronal excitability and in the metabolic effects of the ketogenic diet stands out. Microbiota-modulating strategies have shown promising preliminary results, though the evidence remains insufficient to support broad therapeutic recommendations. The microbiota-gut-brain axis emerges as a relevant and growing field within pediatric neurology, one that calls for longitudinal studies and standardized clinical trials to clarify causality and clinical applicability.