The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/
Abstract
Keywords: Gut-brain axis, enteric microbiota, central nervous system, enteric nervous system, irritable bowel syndrome
Differences in gut microbial composition correlate with regional brain volumes in irritable bowel syndrome
https://microbiomejournal.biomedcent...168-017-0260-z
Abstract
Keywords
Brain-gut-microbiome axis Irritable bowel syndrome Metagenome Firmicutes Bacteroidetes
Update 06/05/2017
The Central Nervous System and the Gut Microbiome
http://www.cell.com/cell/fulltext/S0...showall%3Dtrue
Update 14/06/2017
The Gut Microbiota and Autism Spectrum Disorders
http://journal.frontiersin.org/artic...017.00120/full
Update 20/06/2017
Diet Not Connected to GI Problems in Autistic Children
http://neurosciencenews.com/gi-diet-autism-7070/
Update 13/07/2017
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/
Abstract
The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions. Recent advances in research have described the importance of gut microbiota in influencing these interactions. This interaction between microbiota and GBA appears to be bidirectional, namely through signaling from gut-microbiota to brain and from brain to gut-microbiota by means of neural, endocrine, immune, and humoral links. In this review we summarize the available evidence supporting the existence of these interactions, as well as the possible pathophysiological mechanisms involved. Most of the data have been acquired using technical strategies consisting in germ-free animal models, probiotics, antibiotics, and infection studies. In clinical practice, evidence of microbiota-GBA interactions comes from the association of dysbiosis with central nervous disorders (i.e. autism, anxiety-depressive behaviors) and functional gastrointestinal disorders. In particular, irritable bowel syndrome can be considered an example of the disruption of these complex relationships, and a better understanding of these alterations might provide new targeted therapies.
Differences in gut microbial composition correlate with regional brain volumes in irritable bowel syndrome
https://microbiomejournal.biomedcent...168-017-0260-z
Abstract
Background
Preclinical and clinical evidence supports the concept of bidirectional brain-gut microbiome interactions. We aimed to determine if subgroups of irritable bowel syndrome (IBS) subjects can be identified based on differences in gut microbial composition, and if there are correlations between gut microbial measures and structural brain signatures in IBS.
Methods
Behavioral measures, stool samples, and structural brain images were collected from 29 adult IBS and 23 healthy control subjects (HCs). 16S ribosomal RNA (rRNA) gene sequencing was used to profile stool microbial communities, and various multivariate analysis approaches were used to quantitate microbial composition, abundance, and diversity. The metagenomic content of samples was inferred from 16S rRNA gene sequence data using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). T1-weighted brain images were acquired on a Siemens Allegra 3T scanner, and morphological measures were computed for 165 brain regions.
Results
Using unweighted Unifrac distances with hierarchical clustering on microbial data, samples were clustered into two IBS subgroups within the IBS population (IBS1 (n = 13) and HC-like IBS (n = 16)) and HCs (n = 23) (AUROC = 0.96, sensitivity 0.95, specificity 0.67). A Random Forest classifier provided further support for the differentiation of IBS1 and HC groups. Microbes belonging to the genera Faecalibacterium, Blautia, and Bacteroides contributed to this subclassification. Clinical features distinguishing the groups included a history of early life trauma and duration of symptoms (greater in IBS1), but not self-reported bowel habits, anxiety, depression, or medication use. Gut microbial composition correlated with structural measures of brain regions including sensory- and salience-related regions, and with a history of early life trauma.
Conclusions
The results confirm previous reports of gut microbiome-based IBS subgroups and identify for the first time brain structural alterations associated with these subgroups. They provide preliminary evidence for the involvement of specific microbes and their predicted metabolites in these correlations.
Preclinical and clinical evidence supports the concept of bidirectional brain-gut microbiome interactions. We aimed to determine if subgroups of irritable bowel syndrome (IBS) subjects can be identified based on differences in gut microbial composition, and if there are correlations between gut microbial measures and structural brain signatures in IBS.
Methods
Behavioral measures, stool samples, and structural brain images were collected from 29 adult IBS and 23 healthy control subjects (HCs). 16S ribosomal RNA (rRNA) gene sequencing was used to profile stool microbial communities, and various multivariate analysis approaches were used to quantitate microbial composition, abundance, and diversity. The metagenomic content of samples was inferred from 16S rRNA gene sequence data using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). T1-weighted brain images were acquired on a Siemens Allegra 3T scanner, and morphological measures were computed for 165 brain regions.
Results
Using unweighted Unifrac distances with hierarchical clustering on microbial data, samples were clustered into two IBS subgroups within the IBS population (IBS1 (n = 13) and HC-like IBS (n = 16)) and HCs (n = 23) (AUROC = 0.96, sensitivity 0.95, specificity 0.67). A Random Forest classifier provided further support for the differentiation of IBS1 and HC groups. Microbes belonging to the genera Faecalibacterium, Blautia, and Bacteroides contributed to this subclassification. Clinical features distinguishing the groups included a history of early life trauma and duration of symptoms (greater in IBS1), but not self-reported bowel habits, anxiety, depression, or medication use. Gut microbial composition correlated with structural measures of brain regions including sensory- and salience-related regions, and with a history of early life trauma.
Conclusions
The results confirm previous reports of gut microbiome-based IBS subgroups and identify for the first time brain structural alterations associated with these subgroups. They provide preliminary evidence for the involvement of specific microbes and their predicted metabolites in these correlations.
Brain-gut-microbiome axis Irritable bowel syndrome Metagenome Firmicutes Bacteroidetes
Update 06/05/2017
The Central Nervous System and the Gut Microbiome
http://www.cell.com/cell/fulltext/S0...showall%3Dtrue
Neurodevelopment is a complex process governed by both intrinsic and extrinsic signals. While historically studied by researching the brain, inputs from the periphery impact many neurological conditions. Indeed, emerging data suggest communication between the gut and the brain in anxiety, depression, cognition, and autism spectrum disorder (ASD). The development of a healthy, functional brain depends on key pre- and post-natal events that integrate environmental cues, such as molecular signals from the gut. These cues largely originate from the microbiome, the consortium of symbiotic bacteria that reside within all animals. Research over the past few years reveals that the gut microbiome plays a role in basic neurogenerative processes such as the formation of the blood-brain barrier, myelination, neurogenesis, and microglia maturation and also modulates many aspects of animal behavior. Herein, we discuss the biological intersection of neurodevelopment and the microbiome and explore the hypothesis that gut bacteria are integral contributors to development and function of the nervous system and to the balance between mental health and disease.
The Gut Microbiota and Autism Spectrum Disorders
http://journal.frontiersin.org/artic...017.00120/full
Gastrointestinal (GI) symptoms are a common comorbidity in patients with autism spectrum disorder (ASD), but the underlying mechanisms are unknown. Many studies have shown alterations in the composition of the fecal flora and metabolic products of the gut microbiome in patients with ASD. The gut microbiota influences brain development and behaviors through the neuroendocrine, neuroimmune and autonomic nervous systems. In addition, an abnormal gut microbiota is associated with several diseases, such as inflammatory bowel disease (IBD), ASD and mood disorders. Here, we review the bidirectional interactions between the central nervous system and the gastrointestinal tract (brain-gut axis) and the role of the gut microbiota in the central nervous system (CNS) and ASD. Microbiome-mediated therapies might be a safe and effective treatment for ASD.
Autism spectrum disorder (ASD) constitutes a group of brain developmental disorders, and it is defined by stereotyped behavior and deficits in communication and social interaction. ASD has a significant influence on the development of children and on society. In 2012, the estimated prevalence of ASD was 14.6 per 1,000 children aged 8 years, and the prevalence was significantly higher in boys (23.6 per 1,000) than that in girls (5.3 per 1,000) (Christensen et al., 2016). The cost of caring for a child with ASD but without an intellectual disability is £0.92 million in the United Kingdom and $1.4 million in the United States. The main costs associated with the care of children with ASD are special education services and a loss of parental productivity (Buescher et al., 2014). Therefore, the economic effects of ASD have prompted researchers to search for effective interventions. However, identifying the exact etiology and pathology of ASD is difficult, and available effective therapies are limited (Rossignol and Frye, 2012). Previous studies have focused on genetic causes, dysregulation of the immune system, inflammation, exposure to environmental toxicants, and the gut microbiota (Fakhoury, 2015). The heritability of ASD and autistic disorder was approximately 50% among Swedish children, suggesting that both genetic and environmental factors play important roles in the development of ASD (Hallmayer et al., 2011; Sandin et al., 2014). Accumulating evidence demonstrates that gastrointestinal (GI) symptoms, such as abdominal pain, gaseousness, diarrhea, constipation and flatulence, are a common comorbidity in patients with ASD (Chaidez et al., 2014). A study by Gorrindo et al. identified constipation as the most common symptom (85%) in children with ASD according to parental reports and evaluations by pediatric gastroenterologists (Gorrindo et al., 2012). The prevalence of GI symptoms ranges from 23 to 70% in children with ASD (Chaidez et al., 2014). Furthermore, the observed GI symptoms are associated with the severity of ASD (Adams et al., 2011; Gorrindo et al., 2012). Although these studies did not show a cause-effect relationship between GI symptoms and ASD, the findings suggest that the gut plays an important role in the etiology of ASD. The gut consists of millions of microbiota, and we hypothesize that the microbiota and its metabolites might be involved in the pathophysiology of ASD. Several articles have reviewed the influence of the gut microbiota on the animal central nervous system (CNS) and suggested the existence of a microbiota gut-brain axis (Bienenstock et al., 2015; Mayer et al., 2015). The microbiota-gut-brain axis is likely the method of communication between the brain and the gut microbiota. This article reviews the role of the gut microbiota in the pathology of ASD. Strategies that modulate the gut microbiota might constitute a potential therapy for patients with ASD.
Diet Not Connected to GI Problems in Autistic Children
http://neurosciencenews.com/gi-diet-autism-7070/
Many children with autism spectrum disorder experience significant gastrointestinal issues, but the cause of these symptoms is unknown. Professionals in the medical community have suggested a potential link between diet and gastrointestinal issues related to autism. Now, researchers from the University of Missouri School of Medicine have found that diet is not a contributing factor in these individuals. The researchers hope the findings could help lead to improved treatment options.
“Unfortunately, it’s not uncommon for those with autism to experience constipation, irritable bowel syndrome, abdominal pain and other gastrointestinal issues,” said Brad Ferguson, Ph.D., postdoctoral research fellow in the Department of Radiology at the MU School of Medicine and the MU Thompson Center for Autism and Neurodevelopmental Disorders. “We sought to find out whether nutritional intake in their individual diets was associated with gastrointestinal issues. Based on our findings, dietary intake does not appear to be the culprit for these issues, and other factors are likely at play.”
A previous study conducted by the research team identified a relationship between increased cortisol response to stress and gastrointestinal symptoms in people with autism spectrum disorder. NeuroscienceNews.com image is for illustrative purposes only.
A previous study conducted by the research team identified a relationship between increased cortisol response to stress and gastrointestinal symptoms in people with autism spectrum disorder. Cortisol is a hormone released by the body in times of stress, and one of its functions is to prevent the release of substances in the body that cause inflammation. In this study, the researchers sought to confirm or rule out dietary intake as a source of gastrointestinal problems.
The team studied 75 individuals between the ages of 5 and 18 who are part of the Autism Speaks Autism Treatment Network who were treated at the MU Thompson Center for Autism and Neurodevelopmental Disorders. The individuals’ caregivers completed a questionnaire to assess the children’s gastrointestinal symptoms, as well as a questionnaire on food intake over the past month. The individuals also underwent two stress tests to measure cortisol levels.
“We looked at the reported instances of gastrointestinal issues and compared them with 32 different nutrients found in a standard diet,” Ferguson said. “Contrary to what you may initially think, dietary composition does not appear to be a driving factor between stress response and gastrointestinal function in this sample. More research is needed to better understand the causes of these issues, but an increased reaction to stress does appear to be a contributing factor.”
“Unfortunately, it’s not uncommon for those with autism to experience constipation, irritable bowel syndrome, abdominal pain and other gastrointestinal issues,” said Brad Ferguson, Ph.D., postdoctoral research fellow in the Department of Radiology at the MU School of Medicine and the MU Thompson Center for Autism and Neurodevelopmental Disorders. “We sought to find out whether nutritional intake in their individual diets was associated with gastrointestinal issues. Based on our findings, dietary intake does not appear to be the culprit for these issues, and other factors are likely at play.”
A previous study conducted by the research team identified a relationship between increased cortisol response to stress and gastrointestinal symptoms in people with autism spectrum disorder. NeuroscienceNews.com image is for illustrative purposes only.
A previous study conducted by the research team identified a relationship between increased cortisol response to stress and gastrointestinal symptoms in people with autism spectrum disorder. Cortisol is a hormone released by the body in times of stress, and one of its functions is to prevent the release of substances in the body that cause inflammation. In this study, the researchers sought to confirm or rule out dietary intake as a source of gastrointestinal problems.
The team studied 75 individuals between the ages of 5 and 18 who are part of the Autism Speaks Autism Treatment Network who were treated at the MU Thompson Center for Autism and Neurodevelopmental Disorders. The individuals’ caregivers completed a questionnaire to assess the children’s gastrointestinal symptoms, as well as a questionnaire on food intake over the past month. The individuals also underwent two stress tests to measure cortisol levels.
“We looked at the reported instances of gastrointestinal issues and compared them with 32 different nutrients found in a standard diet,” Ferguson said. “Contrary to what you may initially think, dietary composition does not appear to be a driving factor between stress response and gastrointestinal function in this sample. More research is needed to better understand the causes of these issues, but an increased reaction to stress does appear to be a contributing factor.”
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