Camilleri, Michael

We show how switching from a regular diet to an HCHF increases cholesterol absorption in patients with normal weight and obesity. The decrease in cholesterol absorption from an HCHF to an LCLF, on the other hand, was only seen in normal-weight controls, underlining the importance of body weight in this regulation. In addition, changes in caloric and fat content had an immediate and direct effect on hepatic bile acid production.

SummaryBackgroundTradipitant, an NK1 receptor antagonist, improved symptoms in patients with gastroparesis. It is unclear whether these effects are mediated centrally (e.g., vomiting centre) or on gastric functions. As a class, NK1 antagonists may retard gastric emptying (GE) or increase fasting and postprandial gastric volumes (GV).AimTo evaluate the effects of tradipitant relative to placebo on gastric motor functions, satiation, postprandial symptoms, and pharmacokinetics.MethodsWe conducted a randomised, double‐blind, placebo‐controlled, single‐centre study of tradipitant 85 mg or matching placebo b.i.d. for 9 consecutive days in 24 healthy volunteers. During the last 2 days of treatment, participants underwent scintigraphic measurements of GE of 320 kcal egg meal, fasting and postprandial GV by SPECT, and satiation by nutrient drink ingested to maximum tolerated volume (MTV) and symptoms 30 min later. Treatments were compared by Wilcoxon rank sum test. The study had 80% power to detect group differences of 23.6% in GV and 29.2% in GE T1/2.ResultsThe two groups of healthy participants were well balanced based on demographic features, age, and BMI. There were nonsignificant positive correlations between blood levels of tradipitant and accommodation GV and GE at 4 h. There were no significant effects of tradipitant, 85 mg b.i.d. for 9 days compared to placebo on GE, GV, satiation, or symptoms 30 min after MTV.ConclusionTradipitant, 85 mg b.i.d., does not significantly affect gastric motor functions (GV or GE). Importantly, there was no retardation of GE by tradipitant, which is important in relation to its potential use in patients with gastroparesis.Clinic trials registryClinicalTrials.gov #NCT04849559.

INTRODUCTION: Cannabidiol (CBD), a CBR2 agonist with limited psychic effects, antagonizes CB1/CB2 receptors. Allelic variation CNR1 (gene for CBR1) rs806378 and FAAH rs324420 were associated with altered gut motility and sensation. This study aimed to compare the pharmacodynamics and clinical effects of a 4-week treatment with pharmaceutical-grade CBD vs placebo and assess the interactions of FAAH and CNR1 gene variants on the effects of CBD in patients with functional dyspepsia (FD). METHODS: We performed a randomized, double-blinded, placebo-controlled (1:1 ratio) study of CBD b.i.d. (20 mg/kg/d according to the US Food and Drug Administration escalation guidance) in FD patients with nondelayed gastric emptying (GE) at baseline. Symptoms were assessed by validated daily symptom diary (0–4 scale for upper abdominal pain, nausea, and bloating), weekly assessment of adequate relief, Leuven Postprandial Distress Scale (8 symptoms, adjectival scores rated 0–4 for severity), and quality of life (Short-Form Nepean Dyspepsia Index [average of 10 dimensions each on a 5-point scale]). After the 4-week treatment, all patients underwent measurements of GE of solids, gastric volumes, and Ensure nutrient satiation test. Statistical analysis compared 2 treatments for all endpoints and the effects of CBD in association with FAAH rs324420 and CNR1 rs806378. RESULTS: CBD and placebo effects on physiological functions and patient response outcomes were not significantly different. There were borderline CBD treatment-by-genotype interactions: rs806378 CNR1 with Leuven Postprandial Distress Scale ( P = 0.06) and GE solids ( P = 0.12). DISCUSSION: Approved doses of CBD used off-label do not relieve FD with normal baseline GE of solids or alter gastric motor functions and satiation. CBD treatment-by-gene interactions suggest potential benefits for postprandial distress with CNR1 rs806378 T allele.

This study compares gene expression in mucosa of the terminal ileum, right colon, and left colon in patients with diarrhea- or constipation-predominant irritable bowel syndrome (IBS) and contrasts expression between these two disease entities and also between each entity and mucosa from healthy controls. The study shows there is differential expression of genes related to immune, transmitter, nociceptive, ion channel, and transporter functions, as well as reduced serine protease inhibition, in patients with IBS.

Chronic noncancer pain (CNCP) affects up to 20% of adults and can interfere with activities of daily living. Up to 4% of adults in the United States receive chronic opioid therapy and up to 57% of patients on long-term opioids for CNCP report opioid-induced constipation (OIC). OIC is essentially constipation occurring after starting opioid treatment. While laxatives are traditionally the first-line therapy for OIC, 81% of patients taking daily laxatives and opioids still reported OIC and considered that it negatively affected their quality of life. Naldemedine is a peripherally acting µ-opioid receptor antagonists (PAMORA) approved for the treatment of OIC in patients with CNCP. This article reviews the mechanism of action, efficacy, and safety of naldemedine in CNCP patients. Naldemedine improves OIC in patients with CNCP by acting as an opioid receptor antagonist in the gastrointestinal tract. It does not interfere with the analgesic properties of opioids or cause withdrawal symptoms since these effects are centrally mediated, and naldemedine does not cross the blood brain barrier. Naldemedine showed significant and sustained improvement in frequency of bowel movements, quality of life, and constipation-related symptoms. It is generally well tolerated with a higher incidence of gastrointestinal adverse events of mild or moderate severity such as diarrhea, abdominal pain, or vomiting compared to placebo. While there are no randomized, controlled trials that compare head-to-head pharmacological therapies used for treatment of OIC, network meta-analysis shows that naldemedine has an overall good benefit-risk profile compared to the other approved medications.

AbstractBackgroundRecent studies with functional endoluminal imaging probe (EndoFLIP®) measure physiologic characteristics of the pylorus. EndoFLIP® has the potential to select optimal candidates for gastric peroral endoscopic myotomy (G‐POEM). Normative values of the pylorus using EndoFLIP® have not been established.MethodsTwenty‐four healthy volunteers (20–56 years old; 15 females) underwent unsedated, transoral EndoFLIP® measurements of the pylorus after 8 h of fasting. Measurements of diameter (DM), balloon pressure, and distensibility index (DI) of the pylorus were obtained twice over 5 min at 40, 50, and 60 ml balloon distensions.Key ResultsPyloric DM at 40, 50, and 60 ml balloon distensions were 13.0 ± 2.5, 14.3 ± 1.8, and 17.2 ± 2.0 mm, respectively. DM with 60 ml distension was notably higher than with 40 and 50 ml distensions. Pyloric DI at 40, 50, and 60 ml distensions were 10.9 ± 4.8, 11.3 ± 5.8, and 11.1 ± 4.3 mm2/mm Hg, respectively (p = 0.86). Linear regression and Bland–Altman plots showed similar distribution of the DM and DI during the second minute compared with the full 5‐min measurements at 50 ml distension, as well as between two sequential measurements using 50 ml distension. With 50 ml balloon distension, intraindividual coefficients of variation (COVintra) for DM and DI were 13.8% and 29.6%, respectively, and interindividual COV (COVinter) were 12.6% and 51.3%, respectively. Similar reproducibility was obtained with 40 ml balloon distension.Conclusions and InferencesUnsedated EndoFLIP® can be used to characterize human fasting pyloric diameter and distensibility, with best performance observed with 40 ml and 50 ml distensions and data collection during the second minute. Normative values reported serve as reference values for future studies.

Bile acids are amphipathic, detergent molecules. The detergent effects of di-α-hydroxy-bile acids are relevant to several colonic diseases. The aims were to review the concentrations of bile acids reaching the human colon in health and disease, the molecular structure of bile acids that determine detergent functions and the relationship to human diseases (neuroendocrine tumors, microscopic colitis, active celiac disease, and ulcerative colitis, Crohn’s disease and ileal resection), the relationship to bacterial uptake into the mucosa, mucin depletion, and epithelial damage, the role of bile acids in mucosal inflammation and microscopic colitis, and the role of sulfation of bile salts in detoxification or prevention of the detergent effects of bile acids. The concentrations of bile acids reaching the human colon range from 2 to 10 mM; di-α-hydroxy bile acids are the only bile acids with detergent effects that include mucin depletion, mucosal damage, bacterial uptake, and microscopic inflammation that may be manifest in diseases associated with no overt inflammation of the mucosa, such as bile acid diarrhea, ileal diseases such as neuroendocrine tumors, ileal resection, and nonalcoholic steatohepatitis. Sulfation inactivates colonic secretion due to primary bile acids, but it may render secondary bile acids proinflammatory in the colon. Other evidence in preclinical models of inflammatory bowel disease (IBD) suggests reduced sulfation causes barrier dysfunction, inflammation, or carcinogenesis. These advances emphasize relevance and opportunities afforded by greater understanding of the chemistry and metabolism of bile acids, which stands to be further enhanced by research into the metabolic interactions of microbiota with bile acids.

Abstract Background and Aim Elobixibat is a locally acting inhibitor of the ileal bile acid transporter. We compared bile acid metabolism between healthy subjects and patients with chronic constipation and assessed changes in the bile acid profile after elobixibat administration in the latter group. Methods Healthy subjects ( n = 10) and patients with chronic constipation ( n = 19) were assessed as inpatients for 7 days, during which they received meals containing ~60 g/day of fat. Patients with chronic constipation remained as inpatients for a further 7 days for once‐daily elobixibat administration. Assessments included concentrations of fecal and serum bile acids, serum 7α‐hydroxy‐4‐cholesten‐3‐one (C4) and fibroblast growth factor 19, and bowel movements and constipation symptoms. Results Fecal total and primary bile acids were significantly lower in patients with chronic constipation versus healthy subjects. Serum C4 and fibroblast growth factor 19 levels were comparable between groups. Elobixibat treatment increased fecal total and primary bile acids and decreased levels of fecal lithocholic acid and serum total as well as secondary bile acids in patients with chronic constipation. Bowel movements and other constipation‐related symptoms were also improved by elobixibat to levels almost comparable with those of healthy subjects. Conclusions Despite comparable C4 levels, patients with chronic constipation demonstrated decreased levels of fecal bile acids versus healthy subjects. Elobixibat treatment increased fecal bile acid excretion and reduced serum bile acid concentrations. The improvement of constipation after elobixibat treatment was associated with increased total bile acids, particularly primary bile acids.

Abstract Background Most prevalent gastrointestinal symptoms in multiple sclerosis (MS) relate to lower bowel dysfunction, often in association with bladder manifestations. Objective To assess clinical and objective gastrointestinal motor dysfunctions in patients with MS. Methods This was a single‐center, retrospective study of 166 patients evaluated between 1996 and 2020. We reviewed characterization of the MS, gastrointestinal and neurological symptoms, measurements of gastrointestinal and colonic transit, and anorectal manometry. Key Results At the time of the gastrointestinal evaluations of the 166 patients with MS (138 women; 83%), 111 were in the relapsing‐remitting phase and 52 were in the progressive phase. In 3 patients, disease phase was not assigned due to insufficient data. Constipation was identified in 82% (136/166) of patients. Most [103/116 (88%)] patients with bladder symptoms also had constipation or fecal incontinence. Delayed gastric emptying at 4 h and colonic transit at 24 h was identified in 16% and 7% of the cohort, respectively; 22% had accelerated gastric emptying. On anorectal manometry, resting anal sphincter pressure >90 mm Hg and rectoanal pressure differential below −50mm Hg suggested evacuation disorder in patients with constipation. Conclusions and Inferences In addition to slow colonic transit and anorectal dysfunction leading to constipation in MS, 22% of patients had accelerated gastric emptying.