Volatomics in inflammatory bowel disease and irritable bowel syndrome

Volatile organic compounds (VOCs) are produced by the human metabolism, inflammation and gut microbiota and form the basis of innovative volatomics research. VOCs detected through breath and faecal analysis hence serve as attractive, non-invasive biomarkers for diagnosing and monitoring irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This review describes the clinical applicability of volatomics in discriminating between IBS, IBD and healthy volunteers with acceptable accuracy in breath (70%-100%) and faecal (58%-85%) samples. Promising compounds are propan-1-ol for diagnosing and monitoring of IBD patients, and 1-methyl-4-propan-2-ylcyclohexa-1,4-diene as biomarker for IBS diagnosis. However, these VOCs often seem to be related to inflammation and probably will need to be used in conjunction with other clinical evidence. Furthermore, three interventional studies underlined the potential of VOCs in predicting treatment outcome and patient follow-up. This shows great promise for future use of VOCs as non-invasive breath and faecal biomarkers in personalised medicine. However, properly designed studies that correlate VOCs to IBD/IBS pathogenesis, while taking microbial influences into account, are still key before clinical implementation can be expected. (C) 2020 The Author(s). Published by Elsevier B.V

Chronische obstipatie en rectaal functieonderzoek

Chronic constipation is caused by disordered colonic motility, impaired rectal evacuation (dyschezia) or a combination of the two. It is important to distinguish the predominant mechanism of constipation in order to choose the optimal therapy (laxatives or prokinetics versus pelvic floor retraining or surgery). The contribution of dyschezia to constipation can usually be identified by a digital rectal examination, but should, in our opinion, be confirmed by anal manometry, transrectal ultrasonography or defecography. These diagnostic methods provide additional information on the severity of the rectal outlet obstruction, the contribution of rectal hyposensitivity and the presence of potentially correctable anomalies such as a rectocele, enterocele or rectoanal intussusception. We conclude that clinical anorectal examination and functional studies are both necessary and complementary to each other in the evaluation and management of patients with chronic constipation who do not respond to standard laxative treatmen

Colonoscopy in patients with liver cirrhosis : success and safety issues

Background : Patients with liver cirrhosis undergo screening colonoscopy before liver transplantation. Screening colonoscopy is subject to specific quality criteria, among which caecal intubation rate. Several factors associated with failed caecal intubation have been identified. Aims : We investigated whether liver cirrhosis influenced success and safety of screening colonoscopy. Methods : Caecal intubation and complication rate of 93 candidates for liver transplantation due to liver cirrhosis were compared with the control rates of our endoscopy unit. Several patient and colonoscopy variables were taken into account. Results : In patients with liver cirrhosis caecal intubation rate was only 83%, whereas in the control group it was 94% (P < 0.0001). The presence of high volume ascites tends to compromise a successful colonoscopy. Serious complication rate was 0,4% in controls without colonoscopy-related mortality. In the cirrhotic population two severe complications were encountered (2,2%, P < 0.05) and one patient died due to colonic perforation and sepsis (mortality 1.1%). Conclusions : Caecal intubation rate is significantly lower in patients with liver cirrhosis undergoing screening colonoscopy, possibly related to the presence of ascites. Complication and mortality rate of screening colonoscopy is significantly higher in patients being screened for liver transplantatio

Volatomics in inflammatory bowel disease and irritable bowel syndrome : present and future

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Involvement of afferent neurons in the pathogenesis of endotoxin-induced ileus in mice: role of CGRP and TRPV1 receptors

Activation of neuronal reflex pathways by inflammatory mediators is postulated as an important pathogenic mechanism in postoperative ileus. In this study, we investigated the involvement of afferent neurons and more specifically the role of the transient receptor potential vanilloid receptor type 1 (TRPV1) and calcitonin gene-related peptide (CGRP) in endotoxin-induced motility disturbances in mice. Mice were injected with either lipopolysaccharides (LPS) or saline (control) and pre-treated with hexamethonium (blocker of neuronal transmission), capsaicin (neurotoxin), CGRP 8-37 (CGRP antagonist) or BCTC (TRPV1 receptor antagonist). We measured gastric emptying and intestinal transit of Evans blue next to rectal temperature and a global sickness behaviour scale. In vehicle-treated mice, LPS significantly delayed gastric emptying, small intestinal transit and rectal temperature while the sickness behaviour scale was increased. Hexamethonium, capsaicin, CGRP8-37 and BCTC all reversed the endotoxin-induced delay in gastric emptying and significantly reduced the delay in intestinal transit without effect on the endotoxin-induced decrease in rectal temperature and increase in sickness behaviour scale. Our findings provide evidence for the involvement of afferent nerves in the pathogenesis of endotoxin-induced motility disturbances in mice mediated via CGRP and TRPV1 receptors. Blockade of CGRP and TRPV1 receptors may offer a novel strategy for the treatment of endotoxin-induced ileu