scholarly journals Tryptophan Metabolites Along the Microbiota-Gut-Brain Axis: An Interkingdom Communication System Influencing the Gut in Health and Disease

2020 ◽  
Vol 13 ◽  
pp. 117864692092898 ◽  
Author(s):  
Annalisa Bosi ◽  
Davide Banfi ◽  
Michela Bistoletti ◽  
Cristina Giaroni ◽  
Andreina Baj

The ‘microbiota-gut-brain axis’ plays a fundamental role in maintaining host homeostasis, and different immune, hormonal, and neuronal signals participate to this interkingdom communication system between eukaryota and prokaryota. The essential aminoacid tryptophan, as a precursor of several molecules acting at the interface between the host and the microbiota, is fundamental in the modulation of this bidirectional communication axis. In the gut, tryptophan undergoes 3 major metabolic pathways, the 5-HT, kynurenine, and AhR ligand pathways, which may be directly or indirectly controlled by the saprophytic flora. The importance of tryptophan metabolites in the modulation of the gastrointestinal tract is suggested by several preclinical and clinical studies; however, a thorough revision of the available literature has not been accomplished yet. Thus, this review attempts to cover the major aspects on the role of tryptophan metabolites in host-microbiota cross-talk underlaying regulation of gut functions in health conditions and during disease states, with particular attention to 2 major gastrointestinal diseases, such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), both characterized by psychiatric disorders. Research in this area opens the possibility to target tryptophan metabolism to ameliorate the knowledge on the pathogenesis of both diseases, as well as to discover new therapeutic strategies based either on conventional pharmacological approaches or on the use of pre- and probiotics to manipulate the microbial flora.

2019 ◽  
Vol 20 (6) ◽  
pp. 1482 ◽  
Author(s):  
Andreina Baj ◽  
Elisabetta Moro ◽  
Michela Bistoletti ◽  
Viviana Orlandi ◽  
Francesca Crema ◽  
...  

A complex bidirectional communication system exists between the gastrointestinal tract and the brain. Initially termed the “gut-brain axis” it is now renamed the “microbiota-gut-brain axis” considering the pivotal role of gut microbiota in maintaining local and systemic homeostasis. Different cellular and molecular pathways act along this axis and strong attention is paid to neuroactive molecules (neurotransmitters, i.e., noradrenaline, dopamine, serotonin, gamma aminobutyric acid and glutamate and metabolites, i.e., tryptophan metabolites), sustaining a possible interkingdom communication system between eukaryota and prokaryota. This review provides a description of the most up-to-date evidence on glutamate as a neurotransmitter/neuromodulator in this bidirectional communication axis. Modulation of glutamatergic receptor activity along the microbiota-gut-brain axis may influence gut (i.e., taste, visceral sensitivity and motility) and brain functions (stress response, mood and behavior) and alterations of glutamatergic transmission may participate to the pathogenesis of local and brain disorders. In this latter context, we will focus on two major gut disorders, such as irritable bowel syndrome and inflammatory bowel disease, both characterized by psychiatric co-morbidity. Research in this area opens the possibility to target glutamatergic neurotransmission, either pharmacologically or by the use of probiotics producing neuroactive molecules, as a therapeutic approach for the treatment of gastrointestinal and related psychiatric disorders.


Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2693
Author(s):  
Antonio Corsello ◽  
Daniela Pugliese ◽  
Antonio Gasbarrini ◽  
Alessandro Armuzzi

Diet and nutrition are known to play key roles in many chronic gastrointestinal diseases, regarding both pathogenesis and therapeutic possibilities. A strong correlation between symptomatology, disease activity and eating habits has been observed in many common diseases, both organic and functional, such as inflammatory bowel disease and irritable bowel syndrome. New different dietary approaches have been evaluated in order improve patients’ symptoms, modulating the type of sugars ingested, the daily amount of fats or the kind of metabolites produced in gut. Even if many clinical studies have been conducted to fully understand the impact of nutrition on the progression of disease, more studies are needed to test the most promising approaches for different diseases, in order to define useful guidelines for patients.


2018 ◽  
Author(s):  
Orges Koci ◽  
Michael Logan ◽  
Vaios Svolos ◽  
Richard K. Russell ◽  
Konstantinos Gerasimidis ◽  
...  

With an unprecedented growth in the biomedical literature, keeping up to date with the new developments presents an immense challenge. Publications are often studied in isolation of the established literature, with interpretation being subjective and often introducing human bias. With ontology-driven annotation of biomedical data gaining popularity in recent years and online databases offering metatags with rich textual information, it is now possible to automatically text-mine ontological terms and complement the laborious task of manual management, interpretation, and analysis of the accumulated literature with downstream statistical analysis. In this paper, we have formulated an automated workflow through which we have identified ontological information, including nutrition-related terms in PubMed abstracts (from 1991 until 2016) for two main types of Inflammatory Bowel Diseases: Crohn's Disease and Ulcerative Colitis; and two other gastrointestinal diseases, namely, Coeliac Disease and Irritable Bowel Syndrome. Our analysis reveals unique clustering patterns as well as spatial and temporal trends inherent to the considered gastrointestinal diseases in terms of literature that has been accumulated so far. Although automated interpretation cannot replace human judgement, the developed workflow shows promising results and can be a useful tool in systematic literature reviews. The workflow is available at https://github.com/KociOrges/pytag .


Mouth, Dental, Oesophageal, Stomach, Gastrectomy, Small intestine, Malabsorption, Steatorrhoea, Lactose intolerance, Inflammatory bowel disease, Coeliac disease, Fistulae, stoma, transplantation, Irritable bowel syndrome, colon, Gallbladder


2021 ◽  
Author(s):  
Debora Compare ◽  
Costantino Sgamato ◽  
Olga Maria Nardone ◽  
Alba Rocco ◽  
Pietro Coccoli ◽  
...  

Background: Multiple lines of evidence now support the notion that gut microbiota can contribute to digestive and extra-digestive diseases. The emergence of these observations enabled to postulate a bacteria-centric paradigm upon which to rethink the treatment of many diseases. The goal of therapy should not be to eradicate the flora but to modify it in a way that leads to symptomatic improvement; thus, the interest in the use of probiotics to modulate microbiota composition has increased worldwide in both community and healthcare settings. Summary: The results of published studies are conflicting for most probiotic strains and formulations, and clinicians and consumers need a better understanding of probiotic risks and benefits. Currently, clear guidelines on when to use probiotics and the most effective probiotic for different gastrointestinal conditions are still lacking. Here we reviewed the studies on the use of probiotics in some diseases of relevant interest to gastroenterologists, such as Helicobacter pylori infection, irritable bowel syndrome, and inflammatory bowel disease. Key message: Although the evidence is relevant and promising for probiotics in general, and for specific strains and combinations of strains, it is not yet sufficient to draw unequivocal conclusions and clear recommendations.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5047 ◽  
Author(s):  
Orges Koci ◽  
Michael Logan ◽  
Vaios Svolos ◽  
Richard K. Russell ◽  
Konstantinos Gerasimidis ◽  
...  

With an unprecedented growth in the biomedical literature, keeping up to date with the new developments presents an immense challenge. Publications are often studied in isolation of the established literature, with interpretation being subjective and often introducing human bias. With ontology-driven annotation of biomedical data gaining popularity in recent years and online databases offering metatags with rich textual information, it is now possible to automatically text-mine ontological terms and complement the laborious task of manual management, interpretation, and analysis of the accumulated literature with downstream statistical analysis. In this paper, we have formulated an automated workflow through which we have identified ontological information, including nutrition-related terms in PubMed abstracts (from 1991 to 2016) for two main types of Inflammatory Bowel Diseases: Crohn’s Disease and Ulcerative Colitis; and two other gastrointestinal (GI) diseases, namely, Coeliac Disease and Irritable Bowel Syndrome. Our analysis reveals unique clustering patterns as well as spatial and temporal trends inherent to the considered GI diseases in terms of literature that has been accumulated so far. Although automated interpretation cannot replace human judgement, the developed workflow shows promising results and can be a useful tool in systematic literature reviews. The workflow is available at https://github.com/KociOrges/pytag.


2016 ◽  
Vol 310 (4) ◽  
pp. G234-G239 ◽  
Author(s):  
Laura E. Edgington-Mitchell

Gastrointestinal diseases, such as irritable bowel syndrome, inflammatory bowel disease, and colorectal cancer, affect a large proportion of the population and are associated with many unpleasant symptoms. Although the causes of these diseases remain largely unknown, there is increasing evidence to suggest that dysregulated protease activity may be a contributing factor. Proteases are enzymes that cleave other proteins, and their activity is normally very tightly regulated. During disease, however, the balance between proteases and their inhibitors is often shifted, leading to altered spatial and temporal control of substrate cleavage. Evaluating protease levels in normal physiology and disease has relied heavily on the use of chemical tools. Although these tools have greatly advanced the field, they are not without caveats. This review provides an introduction to these tools, their application in the gut, and a summary of the current knowledge on the contribution of protease activity to gastrointestinal disease.


2018 ◽  
Vol 10 (472) ◽  
pp. eaap8914 ◽  
Author(s):  
Arnau Vich Vila ◽  
Floris Imhann ◽  
Valerie Collij ◽  
Soesma A. Jankipersadsing ◽  
Thomas Gurry ◽  
...  

Changes in the gut microbiota have been associated with two of the most common gastrointestinal diseases, inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Here, we performed a case-control analysis using shotgun metagenomic sequencing of stool samples from 1792 individuals with IBD and IBS compared with control individuals in the general population. Despite substantial overlap between the gut microbiome of patients with IBD and IBS compared with control individuals, we were able to use gut microbiota composition differences to distinguish patients with IBD from those with IBS. By combining species-level profiles and strain-level profiles with bacterial growth rates, metabolic functions, antibiotic resistance, and virulence factor analyses, we identified key bacterial species that may be involved in two common gastrointestinal diseases.


2011 ◽  
Vol 39 (4) ◽  
pp. 1079-1080 ◽  
Author(s):  
Chris S.J. Probert

The diagnosis of IBD (inflammatory bowel disease) is based on the clinical evaluation of symptoms and signs leading to a series of investigations. The investigations used are often unpleasant for patients; they are invasive, costly and potentially dangerous. Patients often report that the odour of flatus, or the gas emitted from faeces, is abnormal during a flare of their IBD. Our group has characterized the VOCs (volatile organic compounds) in the headspace gas emitted from faecal samples from healthy subjects, from patients with infectious diarrhoea and from those with Crohn's disease or ulcerative colitis, both in relapse and remission. Painstaking analysis of gas chromatography–MS data (VOC profiling) has revealed patterns of compounds that are strongly associated with specific infectious diseases and with IBD. These compounds represent a change in the microflora and/or the metabolism of bacteria and/or the epithelium in disease states. These profiles offer a potential for rapid non-invasive assessment of a range of infectious and non-infectious gastrointestinal diseases. The study of VOCs may lead to a better understanding of the pathogenesis of IBD.


2021 ◽  
pp. 109352662110394
Author(s):  
Assaf Hoofien ◽  
Salvatore Oliva ◽  
Marcus Karl-Heinz Auth ◽  
Elena Brook ◽  
Carla Giordano ◽  
...  

Background Accurate measurements of mucosal eosinophil concentrations in gastrointestinal tracts of healthy children are necessary to differentiate health and disease states in general, and better define eosinophilic gastrointestinal diseases. Study We retrospectively reviewed gastrointestinal biopsies from children with macroscopically normal endoscopies, who, after a minimal follow-up of one year, were not diagnosed with any organic disease. Peak eosinophil concentrations and distributions were assessed from each segment of the gastrointestinal tract. Results Three centers (Italy, United Kingdom, and Israel) contributed 202 patients (median age 13 years IQR 9.5–15.5, range 1–18 years). Median (IQR, range) eosinophil concentrations (eos/mm2) were: esophagus 0 (0–0, 0–84), stomach 0 (0–4, 0–84), duodenal bulb 20 (13–30, 7–67), second part of duodenum 20 (13–29, 0–105), terminal ileum 29 (14–51, 0–247), cecum 53 (37–89, 10–232), ascending colon 55 (25–84, 0–236), transverse colon 38 (21–67, 4–181), descending colon 29 (17–59, 0–114), sigmoid colon 25 (13–40, 0–215) and rectum 13 (4–28, 0–152). Significant geographical variance was present, however, no differences in eosinophil concentrations were identified between children with resolving symptoms vs. those with functional diagnoses, nor across age groups. Conclusions Standardized eosinophil concentrations from the gastrointestinal tracts of children without organic disease will serve to better define both health and disease states. No differences were found between resolved symptoms vs. functional diagnoses nor between age groups in this pediatric cohort.


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