New insights into the characterization of the mechanism of action of hyoscine butylbromide in the human colon ex vivo.

INTRODUCTION: Hyoscine butylbromide (HBB) is one of the most used antispasmodics in clinical practice. Recent translational consensus has demonstrated a similarity between human colonic motor patterns studied ex vivo and in vivo, suggesting ex vivo can predict in vivo results. It is unclear whether the mechanism of action of antispasmodics can predict different use in clinical practice. The aim of the present study is to bridge this gap dissecting HBB's role in excitatory and inhibitory neural pathways. METHODS: 309 colon samples from 48 patients were studied in muscle bath experiments. HBB was tested on: 1-spontaneous phasic contractions (SPCs); 2-carbachol-induced contractility; electrical field stimulation (EFS)-induced selective stimulation of 3-excitatory and 4-inhibitory pathways and 5- SPCs and EFS-induced contractions enhanced by neostigmine. Atropine, AF-DX116 (M2 blocker) and DAU-5884 (M3 blocker) were used as comparators. RESULTS: In the presence of tetrodotoxin (TTX), HBB and atropine 1 µM reduced SPCs. HBB and atropine concentration-dependently reduced carbachol- and EFS-induced contractions. Inhibitory effects of DAU-5884 on EFS-induced contractions were more potent than of AF-DX116. HBB did not affect the off-response associated to neural inhibitory responses. Neostigmine enhanced both SPCs and EFS-induced contractions. In the presence of TTX and ω-conotoxin (GVIA), neostigmine still enhanced SPCs. Addition of HBB and atropine reduced these responses. CONCLUSIONS: This study demonstrates that HBB inhibits neural cholinergic contractions associated to muscarinic (mainly M3) receptors. HBB has a potential role in reducing colonic spasm induced by the release of acetylcholine from enteric motor neurons and from an atypical source including a potential non-neuronal origin.

Review document of the Spanish Association of Neurogastroenterology and Motility on the management of opioid-induced constipation.

Opioid induced constipation is a rising problem due to the progressive increment in the prescription of opioids. By contrast to functional constipation, opioid-induced constipation is not a functional gut disorder, but a side effect of the use of opioids. Opioids produce constipation due to a decrease in gastrointestinal motility and a reduction in the gastrointestinal secretions. The treatment of OIC focuses on three basic pillars: optimizing opioid drug indication, preventing constipation onset, and treating it if it occurs. As with any other cause of constipation, lifestyle adjustments and laxatives should be the first-line treatment in the pharmacological management of OIC. Osmotic laxatives such as polyethylene glycol (PEG) are the agents of choice. PEG is inert and is neither fermented nor absorbed in the gastrointestinal tract. Furthermore, it has broad clinical applicability due to its favourable safety profile. If first-line treatments fail, peripheral mu receptor antagonists (PAMORA) are the drugs of choice. They reduce the peripheral effects of OIC with minimal potential to diminish analgesia or induce centrally mediated withdrawal syndrome. Different PAMORA are available in the market, both for oral and subcutaneous administration, with demonstrated efficacy for management of OIC in different clinical trials.

Metabolic response of intestinal microbiota to guar gum consumption.

Background: Guar gum is used extensively as a thickening agent in food, but it remains uncertain whether and to what extent it is fermented by colonic microbiota and whether it has microbiota modulatory properties. Aim: To determine the metabolic response of intestinal microbiota to guar gum consumption, specifically, the extent of initial fermentation and subsequent adaptation. Methods: Single-center, single arm, open label, proof-of-concept study testing the effect of guar gum on microbiota metabolism and adaptation. Healthy male subjects (n = 12) were administered gum guar (8 g/day) for 18 days. Outcomes were measured before, at initial and late administration: (a) anal gas evacuations (number/day); (b) digestive sensations (daily scales); and (c) fecal gut microbiota taxonomy and metabolic functions by shotgun sequencing. Results: At initial consumption, guar gum induced a transient increase in anal gas evacuations and digestive sensations; gas evacuation completely reverted upon continuous administration, whereas sensations reverted only in part. Guar gum induced moderate changes in human microbiota composition at both taxonomic and functional levels. Positive associations between effects on microbiota (proliferation of Agathobaculum butyriciproducens and Lachnospira pectinoschiza) and hedonic sensations were detected. Conclusion: Guar gum is metabolized by intestinal microbiota, and, upon continuous consumption, induces a selective adaptation of microbial taxonomy and function. These data highlight the potential interest of guar gum for novel prebiotic ingredient formulation.

Benefit of extending the protocol for high resolution manometry according to the version 4.0 of the Chicago criteria. A multicenter study.

BACKGROUND: The last version of the Chicago Criteria for high resolution esophageal manometry proposes an expanded protocol including complementary maneuvers to improve the diagnostic yield of the exploration. Our aim was to determine the diagnostic gain of the CCv4.0 protocol compared to the CCv3.0 protocol. METHODS: All manometry recordings performed in 4 reference centers during the first 10 months after the implementation of the new protocol were retrospectively reviewed. The time spent to complete the protocol was measured, and the changes in diagnosis resulting from the new CCv4.0 were compared to CCv3.0. KEY RESULTS: From a total of 756 HRM performed, 606 studies could be properly analyzed. The duration of the studies was 18.3 ± 4.3 min. From these, 11.3 ± 3.4 min were spent to complete the CCv3.0 protocol, and 7.4 ± 3.6 min were spent for the remaining maneuvers. A discordant diagnosis between CCv3.0 and CCv4.0 was obtained in 12% of patients: 32% of patients with ineffective esophageal motility turned to normal motility; 24% of patients with esophagogastric junction outlet obstruction (EGJOO) turned to a non-obstructive disorder; and 1% of patients with an apparently normal EGJ relaxation, turned to an obstructive disorder. EGJOO according to CCv4.0 was more prevalent in patients referred for dysphagia (11%) than those referred for GERD (4%; p = 0.003). CONCLUSIONS AND INFERENCES: Prolongation of the time spent to complete the CCv4.0 protocol leads to a change in the diagnosis of 12% of patients. Clinically relevant changes are mainly related to the evaluation of EGJOO.

Effect of Resistant Dextrin on Intestinal Gas Homeostasis and Microbiota.

Previous studies have shown that a resistant dextrin soluble fibre has prebiotic properties with related health benefits on blood glucose management and satiety. Our aim was to demonstrate the effects of continuous administration of resistant dextrin on intestinal gas production, digestive sensations, and gut microbiota metabolism and composition. Healthy subjects (n = 20) were given resistant dextrin (14 g/d NUTRIOSE®, Roquette Frères, Lestrem, France) for four weeks. Outcomes were measured before, at the beginning, end, and two weeks after administration: anal evacuations of gas during daytime; digestive perception, girth, and gas production in response to a standard meal; sensory and digestive responses to a comfort meal; volume of colonic biomass by magnetic resonance; taxonomy and metabolic functions of fecal microbiota by shotgun sequencing; metabolomics in urine. Dextrin administration produced an initial increase in intestinal gas production and gas-related sensations, followed by a subsequent decrease, which magnified after discontinuation. Dextrin enlarged the volume of colonic biomass, inducing changes in microbial metabolism and composition with an increase in short chain fatty acids-producing species and modulation of bile acids and biotin metabolism. These data indicate that consumption of a soluble fibre induces an adaptative response of gut microbiota towards fermentative pathways with lower gas production.

Differential Effects of Western and Mediterranean-Type Diets on Gut Microbiota: A Metagenomics and Metabolomics Approach.

Our aim was to determine the effect of diet on gut microbiota, digestive function and sensations, using an integrated clinical, metagenomics and metabolomics approach. We conducted a cross-over, randomised study on the effects of a Western-type diet versus a fibre-enriched Mediterranean diet. In 20 healthy men, each diet was administered for 2 weeks preceded by a 2-week washout diet. The following outcomes were recorded: (a) number of anal gas evacuations; (b) digestive sensations; (c) volume of gas evacuated after a probe meal; (d) colonic content by magnetic resonance imaging; (e) gut microbiota taxonomy and metabolic functions by shotgun sequencing of faecal samples; (f) urinary metabolites using untargeted metabolomics. As compared to a Western diet, the Mediterranean diet was associated with (i) higher number of anal gas evacuations, (ii) sensation of flatulence and borborygmi, (iii) larger volume of gas after the meal and (iv) larger colonic content. Despite the relatively little difference in microbiota composition between both diets, microbial metabolism differed substantially, as shown by urinary metabolite profiles and the abundance of microbial metabolic pathways. The effects of the diet were less evident in individuals with robust microbiotas (higher beta-diversity). To conclude, healthy individuals tolerate dietary changes with minor microbial modifications at the composition level but with remarkable variation in microbial metabolism.

The role of liver steatosis as measured with transient elastography and transaminases on hard clinical outcomes in patients with COVID-19.

Liver injury has been widely described in patients with Coronavirus disease 2019 (COVID-19). We aimed to study the effect of liver biochemistry alterations, previous liver disease, and the value of liver elastography on hard clinical outcomes in COVID-19 patients. We conducted a single-center prospective observational study in 370 consecutive patients admitted for polymerase chain reaction (PCR)-confirmed COVID-19 pneumonia. Clinical and laboratory data were collected at baseline and liver parameters and clinical events recorded during follow-up. Transient elastography [with Controlled Attenuation Parameter (CAP) measurements] was performed at admission in 98 patients. All patients were followed up until day 28 or death. The two main outcomes of the study were 28-day mortality and the occurrence of the composite endpoint intensive care unit (ICU) admission and/or death. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were elevated at admission in 130 patients (35%) and 167 (45%) patients, respectively. Overall, 14.6% of patients presented the composite endpoint ICU and/or death. Neither ALT elevations, prior liver disease, liver stiffness nor liver steatosis (assessed with CAP) had any effect on outcomes. However, patients with abnormal baseline AST had a higher occurrence of the composite ICU/death (21% versus 9.5%, p = 0.002). Patients ⩾65 years and with an AST level > 50 U/ml at admission had a significantly higher risk of ICU and/or death than those with AST ⩽ 50 U/ml (50% versus 13.3%, p < 0.001). In conclusion, mild liver damage is prevalent in COVID-19 patients, but neither ALT elevation nor liver steatosis influenced hard clinical outcomes. Elevated baseline AST is a strong predictor of hard outcomes, especially in patients ⩾65 years.

Abdominothoracic Postural Tone Influences the Sensations Induced by Meal Ingestion.

Postprandial objective abdominal distention is frequently associated with a subjective sensation of abdominal bloating, but the relation between both complaints is unknown. While the bloating sensation has a visceral origin, abdominal distention is a behavioral somatic response, involving contraction and descent of the diaphragm with protrusion of the anterior abdominal wall. Our aim was to determine whether abdominal distention influences digestive sensations. In 16 healthy women we investigated the effect of intentional abdominal distention on experimentally induced bloating sensation (by a meal overload). Participants were first taught to produce diaphragmatic contraction and visible abdominal distention. After a meal overload, sensations of bloating (0 to 10) and digestive well-being (-5 to + 5) were measured during 30-s. maneuvers alternating diaphragmatic contraction and diaphragmatic relaxation. Compared to diaphragmatic relaxation, diaphragmatic contraction was associated with diaphragmatic descent (by 21 + 3 mm; p < 0.001), objective abdominal distension (32 + 5 mm girth increase; p = 0.001), more intense sensation of bloating (7.3 + 0.4 vs. 8.0 + 0.4 score; p = 0.010) and lower digestive well-being (-0.9 + 0.5 vs. -1.9 + 0.5 score; p = 0.028). These results indicate that somatic postural tone underlying abdominal distention worsens the perception of visceral sensations (ClinicalTrials.gov ID: NCT04691882).

Different responses of the blockade of the P2Y1 receptor with BPTU in human and porcine intestinal tissues and in cell cultures.

BACKGROUND: Gastrointestinal smooth muscle relaxation is accomplished by activation of P2Y1 receptors, therefore this receptor plays an important role in regulation of gut motility. Recently, BPTU was developed as a negative allosteric modulator of the P2Y1 receptor. Accordingly, the aim of this study was to assess the effect of BPTU on purinergic neurotransmission in pig and human gastrointestinal tissues. METHODS: Ca2+ imaging in tSA201 cells that express the human P2Y1 receptor, organ bath and microelectrodes in tissues were used to evaluate the effects of BPTU on purinergic responses. KEY RESULTS: BPTU concentration dependently (0.1 and 1 µmol L-1 ) inhibited the rise in intracellular Ca2+ evoked by ADP in tSA201 cells. In the pig small intestine, 30 µmol L-1 BPTU reduced the fast inhibitory junction potential by 80%. Smooth muscle relaxations induced by electrical field stimulation were reduced both in pig ileum (EC50  = 6 µmol L-1 ) and colon (EC50  = 35 µmol L-1 ), but high concentrations of BPTU (up to 100 µmol L-1 ) had no effect on human colonic muscle. MRS2500 (1 µmol L-1 ) abolished all responses. Finally, 10 µmol L-1 ADPßS inhibited spontaneous motility and this was partially reversed by 30 µmol L-1 BPTU in pig, but not human colonic tissue and abolished by MRS2500 (1 µmol L-1 ). CONCLUSIONS & INFERENCES: BPTU blocks purinergic responses elicited via P2Y1 receptors in cell cultures and in pig gastrointestinal tissue. However, the concentrations needed are higher in pig tissue compared to cell cultures and BPTU was ineffective in human colonic tissue.

Development and validation of the QUECOMIICAT questionnaire: a tool to assess disease-related knowledge in patients with inflammatory bowel disease

Introduction: adequate knowledge of inflammatory bowel disease (IBD) is essential for a successful patient-centered management of IBD. Objective: due to the scarcity of up-to-date tools for measuring IBD literacy, this single-center, prospective study aimed to develop and validate a new questionnaire to assess IBD-related knowledge. Material and methods: the study included patients followed up at the Crohn-Colitis Care Unit (UACC) at the Hospital Vall d'Hebron (Barcelona, Spain). Patients admitted to the UACC for the first time were subsequently enrolled into a standard IBD educational program. A pilot questionnaire was developed and validated in 92 IBD patients by determining the internal consistency reliability (Cronbach's α test), feasibility, construct validity (correlation with the Crohn's and Colitis Knowledge [CCKNOW] questionnaire and a knowledge visual analog scale [VAS]) and sensitivity (score change before and after a standard IBD educational program). The questionnaire, named "Qüestionari Coneixements Malaltia Inflamatòria Intestinal Catalunya" (IBD-knowledge questionnaire Catalonia) (QUECOMIICAT) was written in Spanish and had 25 items addressing six dimensions: general concepts, clinic, treatment, surgery, habits and social context. Results: the median (interquartile range) completion time was 15 (10-20) minutes and the floor and ceiling effects were 1.1% and 2.1%, respectively. The Cronbach's α coefficient was α = 0.75. QUECOMIICAT significantly correlated with the VAS (rho = 0.34, p < 0.01) and CCKNOW questionnaires (rho = 0.74, p < 0.01). Patient knowledge significantly increased 24 hours after attending a standard IBD educational program and remained statistically significant one month later (Pearson's test-retest correlation coefficient r = 0.81, p < 0.001). Conclusion: in conclusion, the QUECOMIICAT questionnaire is a new up-to-date tool to assess IBD-related knowledge with good feasibility and validation results for use in the routine clinical practice

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Development and validation of the QUECOMIICAT questionnaire: a tool to assess disease-related knowledge in patients with inflammatory bowel disease.

INTRODUCTION: adequate knowledge of inflammatory bowel disease (IBD) is essential for a successful patient-centered management of IBD. OBJECTIVE: due to the scarcity of up-to-date tools for measuring IBD literacy, this single-center, prospective study aimed to develop and validate a new questionnaire to assess IBD-related knowledge. MATERIAL AND METHODS: the study included patients followed up at the Crohn-Colitis Care Unit (UACC) at the Hospital Vall d'Hebron (Barcelona, Spain). Patients admitted to the UACC for the first time were subsequently enrolled into a standard IBD educational program. A pilot questionnaire was developed and validated in 92 IBD patients by determining the internal consistency reliability (Cronbach's α test), feasibility, construct validity (correlation with the Crohn's and Colitis Knowledge [CCKNOW] questionnaire and a knowledge visual analog scale [VAS]) and sensitivity (score change before and after a standard IBD educational program). The questionnaire, named "Qüestionari Coneixements Malaltia Inflamatòria Intestinal Catalunya" (IBD-knowledge questionnaire Catalonia) (QUECOMIICAT) was written in Spanish and had 25 items addressing six dimensions: general concepts, clinic, treatment, surgery, habits and social context. RESULTS: the median (interquartile range) completion time was 15 (10-20) minutes and the floor and ceiling effects were 1.1% and 2.1%, respectively. The Cronbach's α coefficient was α = 0.75. QUECOMIICAT significantly correlated with the VAS (rho = 0.34, p < 0.01) and CCKNOW questionnaires (rho = 0.74, p < 0.01). Patient knowledge significantly increased 24 hours after attending a standard IBD educational program and remained statistically significant one month later (Pearson's test-retest correlation coefficient r = 0.81, p < 0.001). CONCLUSION: in conclusion, the QUECOMIICAT questionnaire is a new up-to-date tool to assess IBD-related knowledge with good feasibility and validation results for use in the routine clinical practice.