Gut microbiota profiles of autism spectrum disorder and attention deficit/hyperactivity disorder: A systematic literature review.

Abstract

Accumulating evidence has implicated an involvement of the gut-brain axis in autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD), however with highly diverse results. This systematic review aims to describe and evaluate studies investigating the gut microbiota composition in individuals with ASD or ADHD and to evaluate if variations in gut microbiota are associated with these disorders.Twenty-four articles were identified in a systematic literature search of PubMed and Embase up to July 22, 2019. They consisted of 20 studies investigating ASD and four studies investigating ADHD. For ASD, several studies agreed on an overall difference in β-diversity, although no consistent bacterial variation between all studies was reported. For ADHD, the results were more diverse, with no clear differences observed.Several common characteristics in gut microbiota function were identified for ASD compared to controls. In contrast, highly heterogeneous results were reported for ADHD, and thus the association between gut microbiota composition and ADHD remains unclear. For both disorders, methodological differences hampered the comparison of studies. ARTICLE HISTORY

Understanding the Link Between Allergy and Neurodevelopmental Disorders: A Current Review of Factors and Mechanisms

“…We also discussed common factors that contribute to the development of both allergy and neurodevelopmental disorders, and they included maternal depression and anxiety ( 43 – 46 ), GDM ( 56 , 57 ), maternal allergic status ( 65 , 66 ), environmental factors such as diet and exposure to environmental pollutants ( 77 , 83 ), microbiome dysbiosis ( 90 , 96 ), and sleep disturbances ( 98 , 102 ). However, there is a lack of direct evidence showing that these factors can connect both allergy and neurodevelopmental disorders.…”

“…These same bacterial species have also been implicated in neurodevelopmental disorders. A review conducted by Bundgaard-Nielsen et al ( 90 ) on the gut microbiota profiles of ADHD and ASD patients presented convincing evidence on altered gut bacterial composition in ASD individuals as compared with healthy controls, which included increase in Bacteroides and Clostridium as well as the decrease in Bifidobacterium, Streptococcus , and Prevotella in stool microbiota. On the other hand, abundance of Parabacteroides, Prevotella , and Lactobacillus were decreased in ADHD patients.…”

“…Downregulation of Bifidobacterium and Lactobacillus , which produce GABA, as well as Streptococcus spp. and Enterococcus spp., which produce serotonin in the stool microbiota of ASD and ADHD patients have been observed ( 90 ). Serotonin and GABA produced by gut bacteria can potentially interact with epithelial cells to stimulate the release of other cytokines and hormones, which in turn regulate neuronal signaling to influence brain functioning ( 88 ).…”

GC-TOF-MS-Based Metabolomic Analysis and Evaluation of the Effects of HX106, a Nutraceutical, on ADHD-Like Symptoms in Prenatal Alcohol Exposed Mice

“…Recently, there are some efforts to control neurological disorders by applying the gut-brain axis theory, a bidirectional communication between the brain and gastrointestinal tract [ 50 , 51 ]. In cases of ADHD, there is evidence demonstrating that gut microbiota affects brain neurodevelopment [ 52 , 53 , 54 , 55 ]. For instance, Szopinska-Tokov et al suggested that inattentive behavior that appeared in ADHD patients is associated with a specific bacterium [ 53 ].…”

Gut Bacteria Shared by Children and Their Mothers Associate with Developmental Level and Social Deficits in Autism Spectrum Disorder

“…Emerging evidence suggests that the gut microbiota may be an important factor in the development of ASD. The structure and composition of gut microbiota in ASD children differ from those in healthy controls (8)(9)(10). Microbiota transfer therapy (MTT) and dietary modulation of gut microbiota can both alleviate gastrointestinal (GI) dysfunction and behavioral symptoms in children with ASD (11,12).…”