Zinsmeister, Alan R.

We report here a novel motor phenomenon that we recorded from the canine terminal ileum in the postprandial period. In chronic models that allowed us to monitor myoelectrical activity and intraluminal pressure from the jejunum and distal ileum, we regularly saw in the ileum, but not in the jejunum, a rhythmic sequence of intraluminal pressure waves at a frequency of 19-24 cycles/min. This unusual motor pattern was rarely seen in the first 2 h after food and was essentially absent during fasting; it appeared reproducibly 1-4 h after food, at the time when chyme reached the ileum. The phenomenon was accompanied by spike bursts that were usually at the same rapid, rhythmic frequency, but the rate of the ileal slow wave persisted at the preprandial level (13-15/min). These findings further exemplify differences in the regulation of the motility between jejunum and ileum; moreover, the phenomenon highlights the capacity of the distal small intestine to response specifically to the nature of its luminal contents. This reaction of the ileum to the arrival of dietary residues is deserving of further study in the evaluation of the small bowel's response to a meal.

The aim of this study was to assess the relationship between altered axial forces and gastric emptying of solids by experimentally inhibiting or stimulating gastric axial forces by intraduodenal lipid or intravenous erythromycin, respectively. In 15 healthy volunteers, we simultaneously measured gastric emptying of solids by scintigraphy, gastroduodenal motility by manometry, and forces along the longitudinal axis of the distal stomach by an axial force transducer. When 25% of the radiolabel had emptied from the stomach, subjects (n = 5 in each group) received normal saline (controls), intraduodenal lipid, or intravenous erythromycin. The test period consisted of the infusion period (10 min) and the subsequent 30 min. Lipid significantly reduced and erythromycin increased axial forces compared with control (lipid: median 0.6 N [0-1.4 interquartile range (IQR)]; erythromycin: median 18.2 N (16.5-20.5 IQR); control: median 4.7 N (3.9-5.2 IQR); P < 0.01). Similarly, antral phasic pressure activities were different relative to control. Gastric axial forces correlated significantly with gastric emptying (Spearman rank correlation = 0.86; P < 0.01). These data are consistent with the hypothesis that axial forces affect gastric emptying of solids and suggest that measurement of axial forces provides an assessment of overall gastric propulsion during the emptying of solids.

We have described previously that the gallbladder responds abnormally to infusions of cholecystokinin octapeptide (CCK-8) in patients with irritable bowel syndrome (IBS). To confirm these results and to examine the possible mechanisms, patients with IBS and predominant symptoms of diarrhea or constipation were compared with matched controls. During infusions of CCK-8 at one of three doses, the response of the gallbladder was measured ultrasonographically. The levels of CCK-8 reached in the peripheral circulation and degradation of the peptide in vitro and in vivo were used to evaluate metabolism of cholecystokinin. We confirmed that the gallbladders of patients with IBS responded abnormally to CCK-8; however, the differences were not due to any prereceptor event. Instead, this abnormality in IBS must be explained by an atypical response at the level of the target tissues.

The contributions of gastric emptying (GE) and gastric accommodation (GA) to satiation, satiety, and postprandial symptoms remain unclear. We aimed to evaluate the relationships between GA or GE with satiation, satiety, and postprandial symptoms in healthy overweight or obese volunteers (total n = 285, 73% women, mean BMI 33.5 kg/m 2 ): 26 prospectively studied obese, otherwise healthy participants and 259 healthy subjects with previous similar GI testing. We assessed GE of solids, gastric volumes, calorie intake at buffet meal, and satiation by measuring volume to comfortable fullness (VTF) and maximum tolerated volume (MTV) by using Ensure nutrient drink test (30 ml/min) and symptoms 30 min after MTV. Relationships between GE or GA with satiety, satiation, and symptoms were analyzed using Spearman rank ( r s ) and Pearson ( R) linear correlation coefficients. We found a higher VTF during satiation test correlated with a higher calorie intake at ad libitum buffet meal ( r s = 0.535, P < 0.001). There was a significant inverse correlation between gastric half-emptying time (GE T 1/2 ) and VTF ( r s = −0.317, P < 0.001) and the calorie intake at buffet meal ( r s = −0.329, P < 0.001), and an inverse correlation between GE Tlag and GE25% emptied with VTF ( r s = −0.273, P < 0.001 and r s = −0.248, P < 0.001, respectively). GE T 1/2 was significantly associated with satiation (MTV, R = −0.234, P < 0.0001), nausea ( R = 0.145, P = 0.023), pain ( R = 0.149, P = 0.012), and higher aggregate symptom score ( R = 0.132, P = 0.026). There was no significant correlation between GA and satiation, satiety, postprandial symptoms, or GE. We concluded that GE of solids, rather than GA, is associated with postprandial symptoms, satiation, and satiety in healthy participants. NEW & NOTEWORTHY A higher volume to comfortable fullness postprandially correlated with a higher calorie intake at ad libitum buffet meal. Gastric emptying of solids is correlated to satiation (volume to fullness and maximum tolerated volume) and satiety (the calorie intake at buffet meal) and symptoms of nausea, pain, and aggregate symptom score after a fully satiating meal. There was no significant correlation between gastric accommodation and either satiation or satiety indices, postprandial symptoms, or gastric emptying.

AbstractBackgroundIt is unknown why functional gastrointestinal disorders (FGIDs) overlap and limited information exists on risk factors for those with overlap. Our aim was to estimate the prevalence of combinations of FGIDs including reflux (FGIDs‐gastroesophageal reflux [GER]), and evaluate potential risk factors for people with multiple disorders in a representative US community.MethodsA population‐based study was conducted by mailing a valid GI symptom questionnaire to an age‐ and gender‐stratified random sample of residents of Olmsted County, MN. Rome III definitions were used to identify people with FGIDs, and GER was defined by weekly or more frequent heartburn or acid regurgitation. The prevalence of people meeting multiple symptom complexes was estimated. Moreover, potential risk factors for people with multiple disorders were evaluated.Key ResultsA total of 3548 people provided data for each of the necessary symptom questions (mean age: 61±16 years, 54% female). Among these 3548 subjects, 2009 (57%) had no FGIDs‐GER, 906 (26%) had a pure FGID‐GER, 372 (10%) had 2 FGIDs‐GER, and 261 (7%) had 3 or more FGIDs‐GER. Somatization as assessed by a higher Somatic Symptom Checklist score (OR=3.3, 95% CI [2.7,4.1]) was associated with an increased odds for those with 3 or more FGIDs‐GER compared to subjects with a pure FGID‐GER adjusting for age and gender.Conclusions and InferencesSymptom complex overlap is common rather than rare in the community. GER is an integral symptom complex associated with both upper and lower FGIDs. Somatization is a strong risk factor for multiple FGIDs.

AbstractBackgroundIn an open‐label study of 26 patients with IBS‐C and chronic constipation, treatment with a vibrating (VIBRANT) capsule twice a week for 7.5 weeks resulted in 88.5% responders. Effects on colonic transit are unclear. We aimed to compare effects of VIBRANT and sham capsule treatment on colonic transit in patients with functional constipation.MethodsPatients with functional constipation (Rome III criteria) were randomized to VIBRANT or sham capsule treatment for 8 weeks and underwent scintigraphic colonic transit measurements during week 8. We estimated the overall rate of colonic transit from the slope of progression of colonic geometric center over 48 hours. The capsule was activated 8 hours after ingestion, and the vibration sequence included 240 cycles.Key ResultsThere were no significant group differences in overall colonic transit [GC48, 2.76 (IQR 2.42‐4.03) for sham group and 3.46 (2.55‐4.61) for active treatment group (P=.13)]. Additionally, the progression of the isotope through the colon was numerically faster, though not significantly different (slope, P=.14) in the VIBRANT capsule group compared to the sham group. Three participants in the VIBRANT capsule group had accelerated colonic transit at 32 hours and faster colonic transit slope compared to the 95th percentile of the sham group.Conclusions and InferencesAlthough there were no group differences between VIBRANT and sham capsule treatment on colonic transit, at least one (and possibly three) of 12 patients receiving the VIBRANT capsule had faster colonic transit. The vibration parameters to accelerate colonic transit in patients with functional constipation require further optimization.

AbstractBackgroundThe prevalence of chronic opioid use among non‐cancer patients presenting with acute abdominal pain (AAP) is unknown. The aim was to characterize opioid use, constipation, diagnoses, and risk factors for surgical diagnoses among non‐cancer patients presenting with AAP to an emergency department (ED).MethodsWe performed a retrospective, observational cohort study of all (n=16,121) adult patients (88% from MN, IA and WI) presenting during 2014 with AAP. We used electronic medical records, and focused on 2352 adults with AAP who underwent abdominal CT scan within 24 hours of presentation. We determined odds ratios of association with constipation and features predicting conditions that may require surgery (surgical diagnosis).Key ResultsThere were 2352 eligible patients; 18.8% were opioid users. Constipation was more frequent in opioid (35.1%) compared to non‐opioid users [OR 2.88 (95% CI 2.28, 3.62)]. Prevalence of surgical diagnosis in the opioid and non‐opioid users was 35.3% and 41.7% respectively (P=.019). By univariate analysis, age and neutrophil count independently predicted increased risk, and chronic opioid use decreased risk of surgical diagnosis. Internal validation of logistic models using a randomly selected validation subset (25% of entire cohort, 587/2352) showed receiver operating characteristic (ROC) curves for the validation and full cohorts were similar.Conclusions and InferencesApproximately 19% of adults presenting with AAP were opioid users; constipation is almost three times as likely in opioid users compared to non‐opioid users presenting with AAP. Factors significantly associated with altered risk of surgical diagnoses were age, opioid use, and neutrophil count.

AbstractBackgroundWhile widely used in clinical practice, the reproducibility of high‐definition anorectal manometry (HD‐ARM) remains unclear. We evaluated the intra‐individual reproducibility of HD‐ARM and compared pressures measured with HD‐ARM and high‐resolution anorectal manometry (HR‐ARM).MethodsThirty‐six women with fecal incontinence had an initial HD‐ARM (HD‐ARM1); on the same day, after randomization, 21 had a second (HD‐ARM2). Sixteen women had a third (HD‐ARM3) 4 weeks later. Twenty‐five had also been evaluated by HR‐ARM previously. Rectoanal pressures were assessed at rest, during squeeze and simulated evacuation. Concordance among pressures was assessed with Lin's concordance correlation coefficient (CCC).Key ResultsAnal resting and squeeze pressures measured with HD‐ARM were reproducible on the same and different days; for average resting pressures of HD‐ARM1 vs HD‐ARM2, CCC = 0.73 (95% confidence interval [CI]: 0.53–0.94), and for HD‐ARM1 vs HD‐ARM3, CCC = 0.60 (95% CI: 0.28–0.93). For maximum squeeze pressures of HD‐ARM1 vs HD‐ARM2, CCC = 0.86 (95% CI: 0.75–0.97), and for HD‐ARM1 vs HD‐ARM3, CCC = 0.56 (95% CI: 0.21–0.91). The rectoanal gradient during evacuation was significantly concordant between HD‐ARM1 and HD‐ARM2 but not HD‐ARM1 and HD‐ARM3. Resting (CCC = 0.38 [95% CI: 0.14–0.62]) and squeeze pressures (CCC = 0.73 [95% CI: 0.57–0.89]) measured with HD‐ARM1 and HR‐ARM were also concordant.Conclusions & InferencesAmong women with fecal incontinence, measurements with HD‐ARM were reproducible on the same (anal resting and squeeze pressures and rectoanal gradient during evacuation) and different days (anal resting and squeeze pressures) and correlated with HR‐ARM measurements. These findings support use of HD‐ARM and HR‐ARM for longitudinal assessments of anal resting and squeeze pressures.