scholarly journals Microbiota-Gut-Brain-Axis and Autism Spectrum Disorders

Author(s):  
Piranavie Srikantha ◽  
M. Hasan Mohajeri

New research points to a possible link between Autism Spectrum Disorder and the gut microbiota as many autistic children have co-occurring gastrointestinal problems. This review focuses on specific alterations of gut microbiota mostly observed in autistic patients. Particularly, the mechanisms through which such alterations may trigger the production of the bacterial metabolites or leaky gut in autistic people are described. Various altered metabolite levels were observed in autistic children, many of those were of bacterial origin such as short chain fatty acids (SCFAs), indoles and lipopolysaccharides. A less integrative gut-blood-barrier is abundant in autistic individuals. This explains the leakage of bacterial metabolites into the patients triggering new body responses or altered metabolism. Some other co-occurring symptoms such as mitochondrial dysfunction, oxidative stress in the cells, altered tight junctions in the blood brain barrier and structural changes in cortex, hippocampus, amygdala and cerebellum were detected. Moreover, this paper suggests that autism is associated with an unbalanced gut microbiota (dysbiosis). Although the cause-effect relationship between autism and gut microbiota is not yet well established, consumption of specific probiotics may represent a powerful tool to re-establish gut homeostasis and promote gut health. Diagnostic and therapeutic value of new biomarkers leading to the perturbation in the phenylalanine metabolism will be discussed.

2019 ◽  
Vol 20 (9) ◽  
pp. 2115 ◽  
Author(s):  
Piranavie Srikantha ◽  
M. Hasan Mohajeri

New research points to a possible link between autism spectrum disorder (ASD) and the gut microbiota as many autistic children have co-occurring gastrointestinal problems. This review focuses on specific alterations of gut microbiota mostly observed in autistic patients. Particularly, the mechanisms through which such alterations may trigger the production of the bacterial metabolites, or leaky gut in autistic people are described. Various altered metabolite levels were observed in the blood and urine of autistic children, many of which were of bacterial origin such as short chain fatty acids (SCFAs), indoles and lipopolysaccharides (LPS). A less integrative gut-blood-barrier is abundant in autistic individuals. This explains the leakage of bacterial metabolites into the patients, triggering new body responses or an altered metabolism. Some other co-occurring symptoms such as mitochondrial dysfunction, oxidative stress in cells, altered tight junctions in the blood-brain barrier and structural changes in the cortex, hippocampus, amygdala and cerebellum were also detected. Moreover, this paper suggests that ASD is associated with an unbalanced gut microbiota (dysbiosis). Although the cause-effect relationship between ASD and gut microbiota is not yet well established, the consumption of specific probiotics may represent a side-effect free tool to re-establish gut homeostasis and promote gut health. The diagnostic and therapeutic value of bacterial-derived compounds as new possible biomarkers, associated with perturbation in the phenylalanine metabolism, as well as potential therapeutic strategies will be discussed.


Gut Pathogens ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Laila Al-Ayadhi ◽  
Naima Zayed ◽  
Ramesa Shafi Bhat ◽  
Nadine M. S. Moubayed ◽  
May N. Al-Muammar ◽  
...  

Abstract Background Innovative research highlighted the probable connection between autism spectrum disorder (ASD) and gut microbiota as many autistic individuals have gastrointestinal problems as co-morbidities. This review emphasizes the role of altered gut microbiota observed frequently in autistic patients, and the mechanisms through which such alterations may trigger leaky gut. Main body Different bacterial metabolite levels in the blood and urine of autistic children, such as short-chain fatty acids, lipopolysaccharides, beta-cresol, and bacterial toxins, were reviewed. Moreover, the importance of selected proteins, among which are calprotectin, zonulin, and lysozyme, were discussed as biomarkers for the early detection of leaky gut as an etiological mechanism of ASD through the less integrative gut–blood–brain barriers. Disrupted gut–blood–brain barriers can explain the leakage of bacterial metabolites in these patients. Conclusion Although the cause-to-effect relationship between ASD and altered gut microbiota is not yet well understood, this review shows that with the consumption of specific diets, definite probiotics may represent a noninvasive tool to reestablish healthy gut microbiota and stimulate gut health. The diagnostic and therapeutic value of intestinal proteins and bacterial-derived compounds as new possible biomarkers, as well as potential therapeutic targets, are discussed.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yu Tian ◽  
Kai-yi Sun ◽  
Tian-qing Meng ◽  
Zhen Ye ◽  
Shi-meng Guo ◽  
...  

Coronavirus disease 2019 (COVID-19) has infected over 124 million people worldwide. In addition to the development of therapeutics and vaccines, the evaluation of the sequelae in recovered patients is also important. Recent studies have indicated that COVID-19 has the ability to infect intestinal tissues and to trigger alterations of the gut microbiota. However, whether these changes in gut microbiota persist into the recovery stage remains largely unknown. Here, we recruited seven healthy Chinese men and seven recovered COVID-19 male patients with an average of 3-months after discharge and analyzed their fecal samples by 16S rRNA sequencing analysis to identify the differences in gut microbiota. Our results suggested that the gut microbiota differed in male recovered patients compared with healthy controls, in which a significant difference in Chao index, Simpson index, and β-diversity was observed. And the relative abundance of several bacterial species differed clearly between two groups, characterized by enrichment of opportunistic pathogens and insufficiency of some anti-inflammatory bacteria in producing short chain fatty acids. The above findings provide preliminary clues supporting that the imbalanced gut microbiota may not be fully restored in recovered patients, highlighting the importance of continuous monitoring of gut health in people who have recovered from COVID-19.


2010 ◽  
Vol 1 (2) ◽  
pp. 189-196 ◽  
Author(s):  
U. Andersson ◽  
C. Bränning ◽  
S. Ahrné ◽  
G. Molin ◽  
J. Alenfall ◽  
...  

Today, the gut microbiota is considered a key organ in host nutritional metabolism and recent data have suggested that alterations in gut microbiota contribute to the development of type 2 diabetes and obesity. Accordingly, a whole range of beneficial effects relating to inflammation and gut health have been observed following administration of probiotics to both humans and different animal models. The objective of this study was to evaluate the metabolic effects of an oral probiotic supplement, Lactobacillus plantarum DSM 15313, to high-fat diet (HFD) fed C57BL/6J mice, a model of human obesity and early diabetes. The mice were fed the experimental diets for 20 weeks, after which the HFD had induced an insulin-resistant state in both groups compared to the start of the study. The increase in body weight during the HFD feeding was higher in the probiotic group than in the control group, however, there were no significant differences in body fat content. Fasting plasma glucose levels were lower in the group fed the probiotic supplement, whereas insulin and lipids were not different. Caecal levels of short-chain fatty acids were not significantly different between the groups. An oral glucose tolerance test showed that the group fed probiotics had a significantly lower insulin release compared to the control group, although the rate of glucose clearance was not different. Taken together, these data indicate that L. plantarum DSM 15313 has anti-diabetic properties when fed together with an HFD.


Autism ◽  
2021 ◽  
pp. 136236132110564
Author(s):  
Samantha Major ◽  
Dmitry Isaev ◽  
Jordan Grapel ◽  
Todd Calnan ◽  
Elena Tenenbaum ◽  
...  

Prior eye-tracking studies involving autistic individuals have focused on total looking time or proportion of looking time to key regions of interest. These studies have not examined another important feature, the ability to sustain attention to stimuli. In particular, the ability to sustain attention to a dynamic social stimulus might reflect more advanced self-regulatory skills that may enhance engagement with and comprehension of social information. In a sample of 155 autistic children (2–8 years of age), we examined children’s average look duration while they viewed a complex, dynamic stimulus containing both social and nonsocial elements. After accounting for children’s age and intelligence quotient, we found that shorter average look duration was associated with increased autism spectrum disorder severity across multiple clinical measures. To calculate average look duration, we divided the length of total looking time in seconds by the total number of uninterrupted looks to the video media. Thus, the ability to sustain attention while viewing complex dynamic information could be important for comprehending dynamic social information. Lay Abstract Many studies of autism look at the differences in how autistic research participants look at certain types of images. These studies often focus on where research participants are looking within the image, but that does not tell us everything about how much they are paying attention. It could be useful to know more about how well autistic research participants can focus on an image with people in it, because those who can look at images of people for longer duration without stopping may be able to easily learn other skills that help them to interact with people. We measured how long autistic research participants watched the video without breaking their attention. The video sometimes had a person speaking, and at other times had toys moving and making sounds. We measured the typical amount of time autistic research participants could look at the video before they looked away. We found that research participants with more severe autism tended to look at the video for shorter amounts of time. The ability to focus without stopping may be related to social skills in autistic people.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1560-1560
Author(s):  
Inah Gu ◽  
Wing Shun Lam ◽  
Daya Marasini ◽  
Cindi Brownmiller ◽  
Brett Savary ◽  
...  

Abstract Objectives Arabinoxylan is a non-starch polysaccharide and rich in wheat, rice and many other cereal grains. Diets high in fiber help promoting gut health in obesity. The objective of this study was to investigate the impact of arabinoxylan from rice bran on the gut microbiota and short chain fatty acids (SCFA) in normal weight (NW) and overweight/obese (OO) subjects through in vitro fecal fermentation. Methods Arabinoxylan was extracted from rice bran fiber. For in vitro fecal fermentation, each fecal sample from NW (n = 6, 3 males and 3 females) and OO (n = 7, 3 males and 4 females) was diluted into anaerobic medium with three treatments: control (no substrates), fructooligosaccharides (FOS, a well-known prebiotic), and arabinoxylan. Samples were incubated at 37˚C and aliquots were taken at 0, 4, 8, 12 and 24 h. SCFA content from samples at all timepoints was analyzed using HPLC. Samples at 0 and 24 h were used for gut microbiota analysis through 16S rRNA gene sequencing. Statistical analyses were performed for the randomized complete block design, where the weight classes are confounded with blocks (subjects). Friedman test was used to determine the difference at 5% level of significance. Results As a result, arabinoxylan treatment significantly increased total SCFA concentration in both NW and OO subjects than control (P < 0.05), comparable to FOS treatment. Between weight classes under arabinoxylan treatment, OO group showed a significantly higher total SCFA content than NW group (P < 0.05). Arabinoxylan changed gut microbial population at the genus level, stimulating Bifidobacterium, Collinsella and Blautia and decreasing Clostridium XIVa and b, Dorea and Oscillibacter (P < 0.05). In addition, different microbiome population was shown in weight classes with three treatments, showing higher Bacteroides in NW and higher Prevotella in OO. Conclusions These results showed that arabinoxylan from rice bran modified gut microbiota in both weight classes, increasing total SCFA content. This study suggests that arabinoxylan from rice bran may have a potential impact on microbial gut health in obesity with prebiotic activities. Funding Sources University of Arkansas.


Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3194
Author(s):  
Jing Wang ◽  
Yong Chen ◽  
Xiaosong Hu ◽  
Fengqin Feng ◽  
Luyun Cai ◽  
...  

The beneficial effects of ginger polyphenols have been extensively reported. However, their metabolic characteristics and health effects on gut microbiota are poor understood. The purpose of this study was to investigate the digestion stability of ginger polyphenols and their prebiotic effects on gut microbiota by simulating digestion and fermentation in vitro. Following simulated digestion in vitro, 85% of the polyphenols were still detectable, and the main polyphenol constituents identified in ginger extract are 6-, 8-, and 10-gingerols and 6-shogaol in the digestive fluids. After batch fermentation, the changes in microbial populations were measured by 16S rRNA gene Illumina MiSeq sequencing. In mixed-culture fermentation with fecal inoculate, digested ginger extract (GE) significantly modulated the fecal microbiota structure and promoted the growth of some beneficial bacterial populations, such as Bifidobacterium and Enterococcus. Furthermore, incubation with GE could elevate the levels of short-chain fatty acids (SCFAs) accompanied by a decrease in the pH value. Additionally, the quantitative PCR results showed that 6-gingerol (6G), as the main polyphenol in GE, increased the abundance of Bifidobacterium significantly. Therefore, 6G is expected to be a potential prebiotic that improves human health by promoting gut health.


Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3300
Author(s):  
Sungji Ha ◽  
Donghun Oh ◽  
Sunghee Lee ◽  
Jaewan Park ◽  
Jaeun Ahn ◽  
...  

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and behavioral impairments. Recent studies have suggested that gut microbiota play a critical role in ASD pathogenesis. Herein, we investigated the fecal microflora of Korean ASD children to determine gut microbiota profiles associated with ASD. Specifically, fecal samples were obtained from 54 children with ASD and 38 age-matched children exhibiting typical development. Systematic bioinformatic analysis revealed that the composition of gut microbiota differed between ASD and typically developing children (TDC). Moreover, the total amounts of short-chain fatty acids, metabolites produced by bacteria, were increased in ASD children. At the phylum level, we found a significant decrease in the relative Bacteroidetes abundance of the ASD group, whereas Actinobacteria abundance was significantly increased. Furthermore, we found significantly lower Bacteroides levels and higher Bifidobacterium levels in the ASD group than in the TDC group at the genus level. Functional analysis of the microbiota in ASD children predicted that several pathways, including genetic information processing and amino acid metabolism, can be associated with ASD pathogenesis. Although more research is needed to determine whether the differences between ASD and TDC are actually related to ASD pathogenesis, these results provide further evidence of altered gut microbiota in children with ASD, possibly providing new perspectives on the diagnosis and therapeutic approaches for ASD patients.


Author(s):  
Baosheng Sun ◽  
Linyue Hou ◽  
Yu Yang

Increasing numbers of researchers are interested in the importance of dietary fiber for the gut microbiota, microbiotal metabolite SCFA, energy metabolism and gut health of the host. However, studies have demonstrated that long-term and longitudinal observation may be needed to evaluate the effect of dietary fiber better, and few such works have been made in chickens. Therefore, we successively fed low-fiber, high--fiber and low-fiber diets to two breeds of chickens during different growth periods (1—8, 9—20 and 21—50 weeks), aiming to longitudinally observe the long-term effect of altered dietary fiber on the gut microbiota, SCFA and development of cecum of chickens with age. The results showed that the composition and function of the gut microbiota, SCFA and the development of the cecum were different during different periods, which was largly affected by dietary fiber. However, the causes of some effects were different during the different periods. For example, compared with that in low-fiber chickens at 8 weeks, dominant fiber-degradation bacteria such as Bacteroidetes, Alloprevotella and SCFA-producing bacteria such as Faecalibacterium increased due to a high-fiber diet at 20 weeks, while due to a high feed intake in 50 weeks. Moreover, the concentration of SCFA in 20 weeks was significantly higher than in 8 weeks and 50 weeks, but the causes of this difference were also distinct. It was proposed that a long-term observation was needed to evaluate the effect of dietary fiber better on chickens. The metabolite pathways of ATP-binding cassette (ABC) transporters encoded by Firmicutes were enriched in 8 weeks, while a two-component system and β–glucosidase encoded by Bacteroidetes were enriched in 20 and 50 weeks. The trend was the same in two breeds of chickens except for Alloprevotella. In addition, the total content of SCFA in the contents of cecum was also affected by the size of the cecum. Surprisingly, the length of the cecum shortened from 20—50 weeks, maybe due to reduced dietary fiber.


Author(s):  
Joanne Tarver ◽  
Silia Vitoratou ◽  
Mathilde Mastroianni ◽  
Natalie Heaney ◽  
Eleanor Bennett ◽  
...  

Abstract Although 70% of autistic children and young people meet criteria for co-occurring psychiatric conditions, there are few screening measures specifically for autistic individuals. We describe the development and validation of the Assessment of Concerning Behavior (ACB), an instrument co-developed with the autistic community to assess mental health and problematic/risky behaviors. Items include descriptions to facilitate symptom recognition by autistic people, and carers/professionals. The ACB was completed by 255 parents, 149 autistic children and young people and 30 teachers. Internal consistency, stability and validity was assessed. The ACB parent-version fit a two-factor model (internalizing and externalizing problems) and showed adequate test–retest reliability, internal consistency and construct validity. The ACB is a promising new measure for research and clinical use in autism.


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