Camilleri, Michael

BackgroundPatients with disorders of gastrointestinal function may undergo unnecessary treatment if misdiagnosed as motility disorders.ObjectiveTo report on clinical features, medical, surgical, and psychiatric comorbidities, and prior treatments of a patient cohort diagnosed concurrently with nonpsychogenic rumination syndrome and pelvic floor dysfunction (also termed rectal evacuation disorder).MethodsFrom a consecutive series (1994–2013) of 438 outpatients with rectal evacuation disorders in the practice of a single gastroenterologist at a tertiary care centre, 57 adolescents or adults were diagnosed with concomitant rumination syndrome. All underwent formal psychological assessment or completed validated questionnaires.ResultsAll 57 patients (95% female) fulfilled Rome III criteria for rumination syndrome; rectal evacuation disorder was confirmed by testing of anal sphincter pressures and rectal balloon evacuation. Prior to diagnosis, most patients underwent multiple medical and surgical treatments (gastrostomy, gastric fundoplication, other gastric surgery, ileostomy, colectomy) for their symptoms. Psychological comorbidity was identified in 93% of patients. Patients were managed predominantly with psychological and behavioural approaches: diaphragmatic breathing for rumination and biofeedback retraining for pelvic floor dysfunction.ConclusionsAwareness of concomitant rectal evacuation disorder and rumination syndrome and prompt identification of psychological comorbidity are keys to instituting behavioural and psychological methods to avoid unnecessary treatment.

SummaryBackgroundHighly selective 5‐HT4agonists have been suggested for the treatment of chronic constipation (CC).AimTo assess the effects of highly selective 5‐HT4agonists (prucalopride, velusetrag or naronapride) on patient‐important clinical efficacy outcomes and safety in adults withCC.MethodsWe searched the medical literature in January 2013 usingMEDLINE/Pubmed, Embase, Cochrane Library, and Web of Science/Scopus for randomised, controlled trials of highly selective 5‐HT4agonists in adults withCC, with no minimum duration of therapy (maximum 12 weeks) or date limitations. Data were extracted from intention‐to‐treat analyses, pooled using a random‐effects model, and reported as relative risk (RR), mean differences, or standardised mean differences with 95% confidence intervals (CI).ResultsMain outcomes included stool frequency, Patient‐Assessment of Constipation Quality of Life (PAC‐QOL),PACof symptoms (PAC‐SYM) and adverse events. Thirteen eligible trials were identified: 11 prucalopride, 1 velusetrag, 1 naronapride. Relative to control, treatment with highly selective 5‐HT4agonists was superior for all outcomes: mean ≥3 spontaneous complete bowel movements (SCBM)/week (RR = 1.85; 95%CI1.23–2.79); mean ≥1SCBMover baseline (RR = 1.57; 95%CI1.19, 2.06); ≥1 point improvement inPAC‐QOLandPAC‐SYMscores. The only active comparator trial of prucalopride andPEG3350 suggestedPEG3350 is more efficacious for some end points. Adverse events were more common with highly selective 5‐HT4agonists, but were generally minor; headache was the most frequent. Most trials studied prucalopride.ConclusionDemonstration of efficacy on patient‐important outcomes and a favourable safety profile support the continued use and development of highly selective 5–HT4agonists in the treatment of chronic constipation.

The study objectives were: to mine the complete exome to identify putative rare single nucleotide variants (SNVs) associated with irritable bowel syndrome (IBS)-diarrhea (IBS-D) phenotype, to assess genes that regulate bile acids in IBS-D, and to explore univariate associations of SNVs with symptom phenotype and quantitative traits in an independent IBS cohort. Using principal components analysis, we identified two groups of IBS-D ( n = 16) with increased fecal bile acids: rapid colonic transit or high bile acids synthesis. DNA was sequenced in depth, analyzing SNVs in bile acid genes ( ASBT, FXR, OSTα/β, FGF19, FGFR4, KLB, SHP, CYP7A1, LRH-1, and FABP6). Exome findings were compared with those of 50 similar ethnicity controls. We assessed univariate associations of each SNV with quantitative traits and a principal components analysis and associations between SNVs in KLB and FGFR4 and symptom phenotype in 405 IBS, 228 controls and colonic transit in 70 IBS-D, 71 IBS-constipation. Mining the complete exome did not reveal significant associations with IBS-D over controls. There were 54 SNVs in 10 of 11 bile acid-regulating genes, with no SNVs in FGF19; 15 nonsynonymous SNVs were identified in similar proportions of IBS-D and controls. Variations in KLB (rs1015450, downstream) and FGFR4 [rs434434 (intronic), rs1966265, and rs351855 (nonsynonymous)] were associated with colonic transit (rs1966265; P = 0.043), fecal bile acids (rs1015450; P = 0.064), and principal components analysis groups (all 3 FGFR4 SNVs; P < 0.05). In the 633-person cohort, FGFR4 rs434434 was associated with symptom phenotype ( P = 0.027) and rs1966265 with 24-h colonic transit ( P = 0.066). Thus exome sequencing identified additional variants in KLB and FGFR4 associated with bile acids or colonic transit in IBS-D.

AbstractBackgroundNausea and vomiting are thought to result from upper gastrointestinal dysfunctions. Our clinical observations led to the hypothesis that colonic motor dysfunction is associated with nausea and vomiting.MethodsWe reviewed electronic medical records (EMR) of 149 patients presenting with complaints of nausea and/or vomiting in a tertiary gastroenterology practice to investigate the association with disorders of colonic motor or evacuation disorders. We extracted demographics, gastric emptying (GEin 149) and colonic transit (CTin 138) of solids, ascending colon emptying half‐time (ACt1/2), rectal evacuation by anorectal manometry (ARM) in 91 and balloon expulsion test (BE) in 55 patients. We estimated the proportions with delayedGEorCT, based on the 5th percentile ofGE(in 319) andCTin 220 healthy volunteers using same method.Key ResultsAmong 11 patients with nausea and/or vomiting with onlyGEmeasured, five had delayed and six normalGE. Among the 149 patients, 77 (52%) patients had evacuation disorders, confirmed by objective tests in 68 patients, and clinical examination in nine patients. In the 138 patients with bothGEandCTmeasured, 106 (76%) had both normalGEandCT, 11 (8%) only delayedGE, 16 (11%) normalGEwith delayedCT, and five (3%) delayedGEandCT. Among 21 patients (15%) with delayedCT, nine had slowACt1/2and 12 evacuation disorder.Conclusions & InferencesIn patients with chronic nausea and/or vomiting in gastroenterology practice, evaluation of colonic motility and rectal evacuation should be considered, since about half the patients have abnormal functions that conceivably contribute to the presenting nausea and/or vomiting.

The contribution of elevated glucagon-like peptide 1 (GLP-1) to postprandial glucose metabolism after Roux-en-Y gastric bypass (RYGB) has been the subject of uncertainty. We used exendin-9,39, a competitive antagonist of GLP-1, to examine glucose metabolism, islet hormone secretion, and gastrointestinal transit in subjects after RYGB and in matched control subjects. Subjects were studied in the presence or absence of exendin-9,39 infused at 300 pmol/kg/min. Exendin-9,39 resulted in an increase in integrated postprandial glucose concentrations post-RYGB (3.6 ± 0.5 vs. 2.0 ± 0.4 mol/6 h, P = 0.001). Exendin-9,39 decreased insulin concentrations (12.3 ± 2.2 vs. 18.1 ± 3.1 nmol/6 h, P = 0.002) and the β-cell response to glucose (ϕTotal, 13 ± 1 vs. 11 ± 1 × 10−9 min−1, P = 0.01) but did not alter the disposition index (DI). In control subjects, exendin-9,39 also increased glucose (2.2 ± 0.4 vs. 1.7 ± 0.3 mol/6 h, P = 0.03) without accompanying changes in insulin concentrations, resulting in an impaired DI. Post-RYGB, acceleration of stomach emptying during the first 30 min by exendin-9,39 did not alter meal appearance, and similarly, suppression of glucose production and stimulation of glucose disappearance were unaltered in RYGB subjects. These data indicate that endogenous GLP-1 has effects on glucose metabolism and on gastrointestinal motility years after RYGB. However, it remains uncertain whether this explains all of the changes after RYGB.

AbstractGhrelin is the endogenous ligand for the growth hormone secretagogue‐1a receptor and is a potential target for treatment of gastroparesis. This viewpoint assesses the potential role of ghrelin agonists in the treatment of gastroparesis through a review of the early phase, randomized, controlled trials of ghrelin agonists in patients with diabetes and, either, delayed gastric emptying at the time of the trial or symptoms at the time of the trial, and prior documentation of delayed gastric emptying of solids. Whereas recent experience with ghrelin agonists that have a macrocycle structure (TZP‐101, TZP‐102) has not confirmed earlier promising results, there is little evidence that ghrelin receptors downregulate with repeated treatment, in contrast to motilin receptors. Phase IIa clinical trials performed with a different agent (RM‐131, which is a small molecule ghrelin agonist) suggest that, as a class, ghrelin agonists may be efficacious in stimulating gastric emptying. It is premature to dismiss ghrelin agonists as potential therapies for gastroparesis.