Autism Spectrum Disorders, ASD
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- Twenty-seven of their 313 metabolites in faeces and serum were also different, and of the 313, two – 5-aminovaleric acid (5AV) and taurine – were also present in lower quantities. These two molecules are neurotransmitter agonists: their molecular structures resemble that of the GABA and glycine neurotransmitters, and they interfere with the latter’s functions.” As it happens, both GABA and glycine, help the brain develop normally.
And when the scientists injected the mice with 5AV and taurine, the rodents developed ASD-like symptoms. Ergo, bacteria probably interfere with brain functions using these molecules. (1)
- Members of the C. histolyticum group are recognized toxin-producers and may contribute towards gut dysfunction, with their metabolic products also exerting systemic effects.
- Strategies to reduce clostridial population levels harboured by ASD patients or to improve their gut microflora profile through dietary modulation may help to alleviate gut disorders common in such patients. (3)
- L. reuteri produces a metabolite that activates the vagus nerve to promote oxytocin, the cuddle hormone.This hormone then turns on the brain reward center for social behavior. Impeding the message at any point along this relay from bacteria to metabolite to vagus nerve to oxytocin receptors impairs the animals sociability (4)
- Blood of mice with autism symptoms had levels of a chemical called 4-ethylphenylsulphate (4EPS) that were 46 times higher than that of the control group. This substance is structurally similar to a chemical called para-cresol that is elevated in people with autism .
- When the researchers injected 4EPS into wild-type mice, they started behaving like the untreated autistic mice - obsessively repeating some behaviours and squeaking differently when greeting other mice. (5)
- ASD mice were fed with Bacteroides fragilis, a gut microbe with positive effects on the immune system, the abundance of 34% of these metabolites changed back, gut barrier integrity was improved, the gut-microbiome was restored to a non-ASD state, and ASD-related behavioral abnormalities were ameliorated. In addition, a 46-fold increase of 4-ethylphenylsulfate (4-EPS) in the serum of MIA offspring returned to normal levels.
-A second metabolite elevated in the MIA serum, and normalized by treatment with B. fragilis, was indolepyruvate. Indolepyruvate is generated by microbial tryptophan catabolism and is related to indolyl-3-acryloylglycine, another human autism marker. Indolepyruvate elevation could be linked to increased serum levels of serotonin, yet another human autism biomarker.
- Application of the B. fragilis probiotic, increased many other metabolites including N-acetylserine, which the authors hypothesize may provide protection against some ASD symptoms. (6)
- Bifidobacterium, Blautia, Dialister, Prevotella, Veillonella, and Turicibacter were consistently decreased, while Lactobacillus, Bacteroides, Desulfovibrio, and Clostridium were increased in patients with ASD relative to HCs in certain studies. (7)
- There is a high coincidence of gastrointestinal (GI) symptoms and compositional changes within the gut microbiome in individuals with ASD.
- The degree of GI symptomatology, including constipation and diarrhea, may correlate with the severity of ASD.
- Microbiome-induced inflammation’s potential to alter the blood-brain barrier (BBB) permeability.
- The same factors affecting gut permeability also affect the permeability of the BBB.
- The translocation of pro-inflammatory molecules across the intestinal barrier causes a low-grade systemic inflammatory response, which can alter the BBB’s permeability
- Specifically, Bacteroidetes, Bacteroides, and Parabacteroides were decreased in oASD mice, with an increase in Akkermansia, Sutterella, and Lachnospiraceae, as has been reported in humans.
- Both the Bacteroides spp. (b20cd_Bacteroides) and P. merdae (4ae7e_Parabacteroides) correlated with reduced repetitive behavior and increased social behavior.
- E. tayi (02b40_Lachnospiraceae) showed the opposite effects, as it correlated with increased repetitive behavior and social interaction deficits
- P. merdae, were more abundant in ASD individuals from human.
- In autism patient Bacteroides, Bifidobacterium, Escherichia coli are reduces and Faecalibacterium, Lactobacillus are increased. The presence of Clostridium remains substantially unchanged
- - Increase in Faecalibacterium in ASD children is responsible for the progression of inflammatory processes, with increased levels of type I interferon, and the alteration of the intestinal barrier.
- - The reduction of Bifidobacterium also results in reduced levels of short-chain fatty acids (SCFAs), common in ASD children.
- - Autism patients who have had their intestinal microbiota remodeled through the administration of antibiotics or bacterial transfer therapy in the intestine, presented with attenuated symptoms of ASD
- Treatment with L. reuteri selectively rescues social deficits in genetic, environmental, and idiopathic ASD models.
- The effects of L. reuteri on social behavior are not mediated by restoring the composition of the host gut microbiome, which is altered in all of these ASD models.
- L. reuteri acts in a vagus nerve-dependent manner and rescues social interaction-induced synaptic plasticity in the ventral tegmental area of ASD mice, but not in oxytocin receptor-deficient mice
- Host genetics and microbiota differentially regulate behaviors in an ASD mouse model
- Microbe therapy (L. reuteri) rescues social deficits in ASD mouse model but not hyperactivity
- Microbe-induced metabolite tetrahydrobiopterin (BH4) selectively rescues social deficits in ASD mouse model
- L. reuteri and tetrahydrobiopterin (BH4) improves in ASD mouse model social-reward-mediated synaptic transmission
- Autism incidence has been found to be higher in the C. difficile diseased population.
- The microbial metabolite p-Cresol induces selectively ASD core behavioral symptoms in mice.
- Social behavior deficits induced by p-Cresol are dependant on changes in microbiota composition.
- L. reuteri produces a metabolite that activates the vagus nerve to promote oxytocin, the cuddle hormone.This hormone then turns on the brain reward center for social behavior. Impeding the message at any point along this relay from bacteria to metabolite to vagus nerve to oxytocin receptors impairs the animals sociability.
- [1.1] Altered gut microbiota and short chain fatty acids in Chinese children with autism spectrum disorder   [Scientific Reports] [Journal]
- [1.2] Specificity of gut microbiota in children with autism spectrum disorder in Slovakia and its correlation with astrocytes activity marker and specific behavioural patterns   [Physiology & Behavior] [Journal]
- [1.3] Fecal microbiota and metabolome of children with autism and pervasive developmental disorder not otherwise specified   [PLOS ONE] [Journal]
- [1.4] Reduced incidence of Prevotella and other fermenters in intestinal microflora of autistic children   [PLOS ONE] [Journal]
- [1.5] Gastrointestinal flora and gastrointestinal status in children with autism-comparisons to typical children and correlation with autism severity   [BMC Gastroenterology] [Journal]
- [1.6] Disturbance of trace element and gut microbiota profiles as indicators of autism spectrum disorder: a pilot study of Chinese children   [Environmental Research] [Journal]
- [1.7] Disturbance of trace element and gut microbiota profiles as indicators of autism spectrum disorder: a pilot study of Chinese children_DUBLICATE   [Environmental Research] [Journal]
- [1.8] Pyrosequencing study of fecal microflora of autistic and control children   [Anaerobe] [Journal]
- [1.9] Differences in fecal microbial metabolites and microbiota of children with autism spectrum disorders   [Anaerobe] [Journal]
- [1.10] Gut microbiota features in young children with autism spectrum disorders   [Frontiers in Microbiology] [Journal]
- [1.11] Gut microbial dysbiosis in Indian children with autism spectrum disorders   [Microbial Ecology] [Journal]
- [1.12] Analysis of gut microbiota profiles and microbe-disease associations in children with austism spectrum disorders in China   [Scientific Reports] [Journal]
- [1.13] New evidences on the altered gut microbiota in autism spectrum disorders   [Microbiome] [Journal]
- [1.14] Alterations of oral microbiota distinguish children with autism spectrum disorders from healthy controls   [Scientific Reports] [Journal]
- [1.15] Gastrointestinal microbiota in children with autism in Slovakia.   [Physiology & Behavior] [Journal]
- [1.16] Gastrointestinal microflora studies in late-onset autism   [Clinical Infectious Diseases] [Journal]
- [1.17] Probiotics: A potential immunotherapeutic approach for the treatment of schizophrenia  [Review]  [Journal of Pharmacy and BioAllied Sciences] [Journal]
- [1.18] Real-time PCR quantitation of Clostridia in feces of autistic children   [Applied and Environmental Microbiology] [Journal]
- [1.19] Alterations in gut glutamate metabolism associated with changes in gut microbiota composition in children with autism spectrum disorder   [mSystems] [Journal]
- [1.20] Altered gut microbiota in Chinese children with autism spectrum disorders   [Frontiers in Cellular and Infection Microbiology] [Journal]
- [1.21] Differences between the gut microflora of children with autistic spectrum disorders and that of healthy children   [Journal of Medical Microbiology] [Journal]
- [1.22] Increased abundance of Sutterella spp. and Ruminococcus torques in feces of children with autism spectrum disorder   [Molecular Autism] [Journal]
- [1.23] Application of novel PCR-based methods for detection, quantitation, and phylogenetic characterization of Sutterella species in intestinal biopsy samples from children with autism and gastrointestinal disturbances   [mBio] [Journal]
- [1.24] New and Preliminary Evidence on Altered Oral and Gut Microbiota in Individuals with Autism Spectrum Disorder (ASD): Implications for ASD Diagnosis and Subtyping Based on Microbial Biomarkers.   [Nutrients] [Journal]
- [1.25] Study of the gut microbiome profile in children with autism spectrum disorder: a single tertiary hospital experience   [Journal of Molecular Neuroscience] [Journal]
- [1.26] Dissecting the contribution of host genetics and the microbiome in complex behaviors  [Research]  [Cell] [Journal]
- [1.27] Gut-Induced Inflammation during Development May Compromise the Blood-Brain Barrier and Predispose to Autism Spectrum Disorder  [Review]  [Clinical Medicine] [Journal]
- [1.28] Human Gut Microbiota from Autism Spectrum Disorder Promote Behavioral Symptoms in Mice  [Research]  [Cell] [Journal]
- [1.29] The Contribution of Gut Microbiota–Brain Axis in the Development of Brain Disorders  [Review]  [Frontiers in Neuroscience] [Journal]
- [1.30] Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder  [Research]  [Neuron] [Journal]
- [1.31] The microbial metabolite p-Cresol induces autistic-like behaviors in mice by remodeling the gut microbiota  [Research]  [Microbiome] [Journal]
- [1.32] Supplements, worms and stool: How families are trying to game the gut to treat autism traits  [Report]  [Others] [Journal]