Once upon a Time Oral Microbiota: A Cinderella or a Protagonist in Autism Spectrum Disorder?

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder evolving over the lifetime of individuals. The oral and gut microbial ecosystems are closely connected to each other and the brain and are potentially involved in neurodevelopmental diseases. This narrative review aims to identify all the available evidence emerging from observational studies focused on the role of the oral microbiome in ASD. A literature search was conducted using PubMed and the Cochrane Library for relevant studies published over the last ten years. Overall, in autistic children, the oral microbiota is marked by the abundance of several microbial species belonging to the Proteobacteria phylum and by the depletion of species belonging to the Bacteroidetes phylum. In mouse models, the oral microbiota is marked by the abundance of the Bacteroidetes phylum. Oral dysbiosis in ASD induces changes in the human metabolome, with the overexpression of metabolites closely related to the pathogenesis of ASD, such as acetate, propionate, and indoles, together with the underexpression of butyrate, confirming the central role of tryptophan metabolism. The analysis of the literature evidences the close relationship between oral dysbiosis and autistic core symptoms; the rebuilding of the oral and gut ecosystems by probiotics may significantly contribute to mitigating the severity of ASD symptoms.

State of the Art in the Diagnosis and Assessment of Oral Malignant and Potentially Malignant Disorders: Present Insights and Future Outlook—An Overview

“…Pathological cytoarchitectural changes in the tissue layers of the oral mucosa are seen in a wide range of disorders, ranging from benign [ 22 ] to potentially malignant and properly malignant conditions [ 23 , 24 , 25 , 26 ], up to the involvement of rare syndromic manifestations involving multiple areas of the body [ 27 , 28 ]. Benign disorders affecting the oral mucosa represent a large group of pathological manifestations, especially autoimmune, viral and neuropsychiatric diseases [ 29 , 30 , 31 , 32 , 33 , 34 ]. However, the oral cavity is linked to the possible occurrence of malignant lesions, and 90% of them are represented by Oral Squamous Cell Carcinoma (OSCC), the 16th most common worldwide cancer [ 35 ].…”