Citations

AbstractBackgroundCurrently, anorectal manometry (ARM), which is used to diagnose defecatory disorders and identify anal weakness in fecal incontinence (FI) is generally conducted in specialized laboratories. Our aims were to compare anorectal functions measured with high‐resolution manometry (HRM) and a novel portable manometry device.MethodsAnal pressures at rest, during squeeze, and simulated evacuation, and rectal sensation were evaluated with portable and HRM in 20 healthy women, 19 women with constipation, and 11 with FI. The relationship between anal pressures measured with portable and HRM was assessed by the concordance correlation coefficient (CCC), Bland Altman test, and paired t‐tests.Key ResultsAnal pressures at rest (CCC 0.45; 95% CI: 0.29, 0.58) and during squeeze (CCC 0.60; 95% CI: 0.46, 0.72) measured with portable and HRM were correlated and inversely associated with the risk of FI. During simulated evacuation, the CCC for rectal pressure (0.62; 95% CI: 0.43, 0.76) was greater than that for anal pressure (CCC 0.22; 95% CI: 0.04, 0.39) and the rectoanal gradient (CCC 0.22; 95% CI: 0.02, 0.41). Rectal sensory thresholds for first sensation, the desire to defecate, and urgency measured by portable and HRM were also significantly correlated between techniques. For several parameters, differences between portable and HRM were statistically significant and the Bland Altman test was positive.Conclusions & InferencesAnorectal pressures and rectal sensation can be conveniently measured by portable manometry and are significantly correlated with high‐resolution manometry.

ObjectiveTo examine the association of gene variants of uncoupling proteins (UCP)‐2 and −3 with obesity and gastrointestinal (GI) traits.MethodsIn 255 overweight or obese adults, the associations of gene variants in UCP‐2 (−3474, rs659366) and UCP‐3 (rs1626521, rs2075577, rs15763) with body weight (BW) and GI traits were studied. Gene variants were genotyped by TaqMan® assay. The associations of genotypes with BW and GI traits (gastric emptying, gastric volume, satiety by buffet meal, satiation by nutrient drink test and GI hormones) were assessed using ANOVA corrected for false detection rate (FDR).ResultsA novel UCP‐3 gene variant, rs1626521, was identified; it was associated with BW (P = 0.039), waist circumference (P = 0.035), and significantly higher postprandial gastric volume (P = 0.003) and calories ingested at buffet meal (P = 0.006, both significant with FDR). In a subgroup of 11 participants, rs1626521 was also associated with reduced mitochondrial bioenergetics efficiency in skeletal muscle (P = 0.051). In an in vitro study in HEK293 cells, rs1626521 reduced UCP‐3 protein expression (P = 0.049). Associations detected between other genotypes and GI traits were nonsignificant with FDR.ConclusionsA newly identified functional variant (rs1626521) in UCP‐3 affects postprandial gastric functions and satiety and may contribute to weight gain and alter human mitochondrial function.

To compare the effects of the κ-opioid agonist asimadoline and placebo on visceral sensation and gastrointestinal (GI) motor functions in humans, 91 healthy participants were randomized in a double-blind fashion to 0.15, 0.5, or 1.5 mg of asimadoline or placebo orally twice a day for 9 days. We assessed satiation (nutrient drink test), colonic compliance, tone, perception of colonic distension (barostat), and whole gut transit (scintigraphy). Treatment effect was assessed by analysis of covariance. Asimadoline increased nutrient drink intake ( P = 0.03). Asimadoline decreased colonic tone during fasting ( P = 0.03) without affecting postprandial colonic contraction, compliance, or transit. Gas scores in response to colonic distension were decreased with 0.5 mg of asimadoline at low levels (8 mmHg above operating pressure) of distension ( P = 0.04) but not at higher levels of distension. Asimadoline at 1.5 mg increased gas scores at 16 mmHg of distension ( P = 0.03) and pain scores at distensions of 8 and 16 mmHg ( P = 0.003 and 0.03, respectively) but not at higher levels of distension. Further studies of this compound in diseases with altered satiation or visceral sensation are warranted.

Colonic transit is slowed in patients with disordered rectal evacuation, but the mechanism of this phenomenon is unclear. Our objective was to investigate rectocolonic inhibitory reflexes in humans to provide potential insight into patients with obstructed defecation. In 30 healthy subjects, a barostat-manometric assembly recorded colonic tone and phasic activity in the descending colon during rectal distension and recorded rectal tone during colonic distension. Phasic distensions were 8, 16, and 32 mmHg above balloon operating pressure, and staircase inflations were comprised of balloon inflation then deflation in 2-mmHg increments at 30-s intervals from 0 to 36 mmHg. Colonic balloon volumes increased to a similar extent during phasic rectal distensions 8, 16, and 32 mmHg above operating pressure, reflecting reduced colonic tone; balloon volumes also increased and phasic pressure activity decreased during staircase rectal distensions. In contrast, rectal balloon volume declined, reflecting increased tone during phasic and staircase colonic distensions. Thus rectal distension inhibited colonic motor activity, indicative of a viscerovisceral inhibitory reflex.

Summary Background About one‐third of patients with IBS ‐diarrhoea (irritable bowel syndrome‐D) have evidence of increased bile acid synthesis or excretion. Aims To assess effects of the bile acid sequestrant, colesevelam, on faecal excretion of BA s, hepatic BA synthesis and diarrhoea in IBS ‐D; to appraise whether individual or random stool samples accurately reflect 48‐h total faecal bile acid excretion and proportions of the main bile acids excreted and to study the faecal fat excretion in response to colesevelam. Methods A single‐centre, unblinded, single‐dose trial of effects of colesevelam, 1875 mg [3 tablets (625 mg tablets)] orally, twice daily, for 10 days on total 48‐h faecal bile acid excretion and fasting serum C4 (7α‐hydroxy‐4‐cholesten‐3‐one; surrogate of hepatic bile acid synthesis). Stool diaries documented bowel functions for 8 days prior and 8 days during colesevelam treatment. Stool 48‐h samples and fasting serum were collected for faecal fat, faecal bile acid and serum C4. Results Colesevelam was associated with significantly increased faecal total bile acid excretion and deoxycholic acid excretion, increased serum C4 and more solid stool consistency. There was a significant inverse correlation between number of bowel movements per week and the total bile acid sequestered into stool during the last 48 h of treatment. Random stool samples did not accurately reflect 48‐h total or individual faecal bile acid excretion. Sequestration of bile acids by colesevelam did not increase faecal fat. Conclusions Colesevelam increases delivery of bile acids to stool while improving stool consistency, and increases hepatic bile acid synthesis, avoiding steatorrhoea in patients with IBS ‐D. Overall effects are consistent with luminal bile acid sequestration by colesevelam.

Abstract Background Gastrointestinal symptoms are common in the postural orthostatic tachycardia syndrome ( POTS ). However, few studies have evaluated gastrointestinal transit in POTS . Our primary objectives were to evaluate gastrointestinal emptying and the relationship with autonomic dysfunctions in POTS . Methods We reviewed the complete medical records of all patients aged 18 years and older with POTS diagnosed by a standardized autonomic reflex screen who also had a scintigraphic assessment of gastrointestinal transit at Mayo Clinic Rochester between 1998 and 2012. Associations between specific gastric emptying and autonomic (i.e., cardiovagal, adrenergic, and sudomotor) disturbances were evaluated. Key Results Among 163 patients (140 women, mean [± SEM ] age 30 [±1] years), 55 (34%) had normal, 30 (18%) had delayed, and 78 (48%) had rapid gastric emptying. Fifty‐eight patients (36%) had clinical features of physical deconditioning, which was associated ( p = 0.02) with rapid gastric emptying. Associations with delayed gastric emptying included vomiting, which was more common ( p < 0.003), and anxiety or depression, which was less common ( p = 0.02). The tilt‐associated increase in heart rate and reduction in systolic BP at 1 min was associated ( p < 0.05), being greater in patients with delayed gastric emptying. Conclusions & Inferences Two‐thirds of patients with POTS and GI symptoms had abnormal, most frequently rapid gastric emptying. Except for more severe adrenergic impairment in patients with delayed gastric emptying, the pattern of autonomic dysfunction did not discriminate among gastric emptying groups. Further studies are necessary to ascertain whether extravascular volume depletion and/or deconditioning contribute to POTS in patients with gastrointestinal symptoms.

BackgroundChronic constipation (CC) is common in the community but surprisingly little is known about relevant gastro‐intestinal (GI) and non‐GI co‐morbidities.ObjectiveThe purpose of this study was to assess the epidemiology of CC and in particular provide new insights into the co‐morbidities linked to this condition.MethodsIn a prospective, population‐based nested case‐control study, a cohort of randomly selected community residents (n = 8006) were mailed a validated self‐report gastrointestinal symptom questionnaire. CC was defined according to Rome III criteria. Medical records of each case and control were abstracted to identify potential CC comorbidities.ResultsAltogether 3831 (48%) subjects returned questionnaires; 307 met criteria for CC. Age‐adjusted prevalence in females was 8.7 (95% confidence interval (CI) 7.1–10.3) and 5.1 (3.6–6.7) in males, per 100 persons. CC was not associated with most GI pathology, but the odds for constipation were increased in subjects with anal surgery relative to those without (odds ratio (OR) = 3.3, 95% CI 1.2–9.1). In those with constipation vs those without, neurological diseases including Parkinson’s disease (OR = 6.5, 95% CI 2.9–14.4) and multiple sclerosis (OR = 5.5, 95% CI 1.9–15.8) showed significantly increased odds for chronic constipation, adjusting for age and gender. In addition, modestly increased odds for chronic constipation in those with angina (OR = 1.4, 95% CI 1.1–1.9) and myocardial infarction (OR = 1.5, 95% CI 1.0–2.4) were observed.ConclusionsNeurological and cardiovascular diseases are linked to constipation but in the community constipation is unlikely to account for most lower GI pathology.

AbstractBackgroundDysphagia is considered an alarm symptom but detailed population‐based data on dysphagia are lacking. We aimed to estimate in a representative USA Caucasian population, the prevalence of dysphagia and potential risk factors.MethodsA modified version of the previously validated Bowel Disease Questionnaire was mailed to a population‐based cohort (n = 7640) of Olmsted County, MN. Dysphagia was measured by one validated question ‘In the last year, how often have you had difficulty swallowing (a feeling that food sticks in your throat or chest)?’ The medical records were reviewed for organic causes of dysphagia. The associations of reported frequency of dysphagia with potential risk factors were assessed using logistic regression models.Key ResultsThe sex‐specific, age‐adjusted (US White 2000) prevalence for dysphagia experienced at least weekly was 3.0% (95% CI: 2.2, 3.7) in females and 3.0% (95% CI: 2.0, 4.0) in males. Those with frequent heartburn (OR = 5.9 [4.0, 8.6]) and acid regurgitation (OR = 10.6 [6.8, 16.6]) were significantly more likely to report frequent dysphagia. Proton pump inhibitor (PPI) use was significantly associated with frequent (3.1, 95% CI 2.2, 4.4) and infrequent dysphagia (1.5, 955 CI 1.3, 1.8). Gastro‐esophageal reflux disease (GERD) was the most common diagnosis in those reporting dysphagia on the medical record; other organic explanations were rare and only found in the frequent dysphagia group.Conclusions & InferencesFrequent dysphagia is not rare in the community (3%), occurs in both women and men across all adult age groups, and is most likely to indicate underlying GERD.

AbstractBackgroundA valid biomarker is ‘an indicator of normal biologic or pathogenic processes, or pharmacological responses to a therapeutic intervention’. There is no validated biomarker for irritable bowel syndrome (IBS). The aim of the study was to assess ability of three quantitative traits to identify treatable processes to discriminate between IBS‐diarrhea (IBS‐D) patients, IBS‐constipation (IBS‐C) patients and healthy volunteers (HV).MethodsIn 30 HV, 30 IBS‐C patients and 64 IBS‐D patients, we characterized bowel symptoms and quantitated pathophysiological mechanisms: bile acid (BA) synthesis (serum C4 and FGF19), fecal BA and fat, colonic transit (CT), and intestinal permeability (IP). We used multiple logistic regression and receiver‐operating characteristic (ROCAUC) to appraise three factors (fecal BA, CT, and IP) individually and in combination to identify discriminant targets for treatment in IBS.Key ResultsThere were significant associations between the three subgroups and symptoms reflecting bowel function and the quantitative traits. There were significant associations between fecal BA and CT at 48 h (r = 0.43; p < 0.001) and between fecal BA and IP (r = 0.23; p = 0.015). Individually, fecal BA and CT48 (but not IP) were significant independent predictors for distinguishing HV from IBS. In combination, they discriminated HV from IBS‐D patients (ROCAUC 0.70), HV from IBS‐C patients (ROCAUC 0.73), and IBS‐C patients from IBS‐D patients (ROCAUC 0.86). Colonic transit and fecal BA excretion together discriminate between healthy volunteers and IBS‐C patients or IBS‐D patients, or between the IBS subgroups with 75–90% specificity at 60% sensitivity.Conclusions & InferencesColonic transit and fecal BA individually and together constitute useful biomarkers to identify treatable mechanisms in IBS and to differentiate subgroups of IBS.

AbstractBackgroundHeme oxygenase 1 (HO‐1) degrades heme and protects against oxidative stress. In vitro and animal models suggest that HO‐1 is beneficial in several diseases (e.g., postoperative ileus, gastroparesis, acute pancreatitis, and colitis). However, the only drugs (i.e., hemin and heme arginate) which pharmacologically upregulate HO‐1 in humans are expensive and can only be administered intravenously. Our aims were to compare the effects of placebo, aspirin, and simvastatin alone, and with α‐lipoic acid, on HO‐1 protein concentration and activity in humans.MethodsThis randomized, double‐blind, placebo‐controlled study compared the effects of three oral regimens administered for 7 days, i.e., placebo; aspirin (325 mg twice daily) and simvastatin (40 mg twice daily); aspirin, simvastatin, and the sodium salt of R‐ α‐lipoic acid (NaRLA, 600 mg three times daily) on markers of HO‐1 activation (i.e., plasma HO‐1 protein concentration and venous monocyte HO‐1 protein activity) in 18 healthy subjects (14 females). Markers of HO‐1 activation were evaluated at baseline, days 2, and 7.Key ResultsBaseline HO‐1 protein concentrations and activity were similar among the three groups. Compared to placebo, aspirin and simvastatin combined, or together with NaRLA did not affect HO‐1 protein concentration or activity at 2 or 7 days. HO‐1 protein concentrations and activity were correlated on day 7 (r = 0.75, p = 0.0004) but not at baseline and on day 2.Conclusions & InferencesAt therapeutic doses, aspirin, simvastatin, and α‐lipoic acid do not increase plasma HO‐1 protein concentration or venous monocyte HO‐1 activity in healthy humans.