Brain mediators of negative affect-induced physical symptom reporting in patients with functional somatic syndromes.

Functional somatic syndromes (FSS) include fibromyalgia, irritable bowel syndrome (IBS), and others. In FSS patients, merely viewing negative affective pictures can elicit increased physical symptoms. Our aim was to investigate the neural mechanisms underlying such negative affect-induced physical symptoms in FSS patients. Thirty patients with fibromyalgia and/or IBS and 30 healthy controls (all women) watched neutral, positive and negative affective picture blocks during functional MRI scanning and rated negative affect and physical symptoms after every block. We compared brain-wide activation during negative versus neutral picture viewing in FSS patients versus controls using robust general linear model analysis. Further, we compared neurologic pain signature (NPS), stimulus intensity-independent pain signature (SIIPS) and picture-induced negative emotion signature (PINES) responses to the negative versus neutral affect contrast and investigated whether they mediated between-group differences in affective picture-induced physical symptom reporting. More physical symptoms were reported after viewing negative compared to neutral pictures, and this effect was larger in patients than controls (p = 0.025). Accordingly, patients showed stronger activation in somatosensory regions during negative versus neutral picture viewing. NPS, but not SIIPS nor PINES, responses were higher in patients than controls during negative versus neutral pictures (p = 0.026). These differential NPS responses partially mediated between-group differences in physical symptoms. In conclusion, picture-induced negative affect elicits physical symptoms in FSS patients as a result of activation of somatosensory and nociceptive brain patterns, supporting the idea that affect-driven alterations in processing of somatic signals is a critical mechanism underlying FSS.

The Rome Foundation Global Epidemiology study: Research opportunities national and worldwide.

The Rome Foundation embarked on an ambitious multi-year, multinational population-based study to evaluate the prevalence of Rome IV-defined DGBI and their biopsychosocial impact on a worldwide scale. The consistency of the study findings attests to the scientific rigor of this effort, as evident in the publications that resulted from this international study. Dr. Sperber and colleagues report a subanalysis on the Rome IV Global Epidemiology internet survey of the 2012 adults in Israel. These data determined the national prevalence of Rome IV-defined DGBIs, and their associated healthcare utilization and sociodemographic and psychosocial variables. Importantly, they also permitted seamless comparison of the data in the rest of the world. The Israeli study highlights some of the strengths of the Global Epidemiology Study: the 2 respondents had a geographical spread representative of the country. The questionnaire in Israel was available to the participants online in four different languages used by the population in Israel: The database of the study is now available through the Rome Foundation Research Institute for use by academic and industry researchers. This unique gift from the Rome Foundation to the scientific community no doubt will further enhance our understanding of disorders of gut-brain interaction.

Transient hypopharyngeal intrabolus pressurization patterns: Clinically relevant or normal variant?

INTRODUCTION: In oropharyngeal dysphagia, impaired pharyngoesophageal junction (PEJ) opening is reflected by an elevated hypopharyngeal intrabolus pressure (IBP), quantifiable using pharyngeal high-resolution manometry with impedance (P-HRM-I). Transient intrabolus pressurization (TP) phenomena are not sustained and last for only a brief period. We hypothesized that TP patterns reflect impaired coordination between timing of hypopharyngeal bolus arrival and PEJ relaxation. METHODS: A retrospective audit was conducted of P-HRM-I datasets; 93 asymptomatic Controls and 214 Patients with differing etiological/clinical backgrounds were included. TP patterns were examined during 10ml liquid swallows. TP was defined by a simultaneous, non-sustained, pressurization wave spanning from the velo-/meso-pharynx to PEJ. The coordination between deglutitive pharyngeal bolus distension and PEJ relaxation timing was assessed using timing variables; (i) Distention-Contraction Latency (DCL, s) and (ii) PEJ Relaxation Time (RT, s). Resultant flow resistance was quantified (IBP, mmHg). RESULTS: TP swallows were observed in 87 (28%) cases. DCL was not significantly different in relation to TP, while PEJ relaxation time was shorter, and IBP was higher during TP swallows. In Patients RT-DCL time difference correlated with IBP (r -0.368, p < 0.01). CONCLUSION: Bolus distension and PEJ relaxation were miss-timed during TP swallows, impeding bolus flow and leading to a brief period of pressurization of the pharyngeal chamber by muscular propulsive forces. While TP swallows were identified in both Controls and Patients, increased IBPs were most apparent for Patient swallows indicating that the extent of IBP increase may differentiate pathological TP swallows.

A survey of functional dyspepsia in 361,360 individuals: Phenotypic and genetic cross-disease analyses.

BACKGROUND: Functional dyspepsia (FD) is a common gastrointestinal condition of poorly understood pathophysiology. While symptoms' overlap with other conditions may indicate common pathogenetic mechanisms, genetic predisposition is suspected but has not been adequately investigated. METHODS: Using healthcare, questionnaire, and genetic data from three large population-based biobanks (UK Biobank, EGCUT, and MGI), we surveyed FD comorbidities, heritability, and genetic correlations across a wide spectrum of conditions and traits in 10,078 cases and 351,282 non-FD controls of European ancestry. KEY RESULTS: In UK Biobank, 281 diagnoses were detected at increased prevalence in FD, based on healthcare records. Among these, gastrointestinal conditions (OR = 4.0, p < 1.0 × 10-300 ), anxiety disorders (OR = 2.3, p < 1.4 × 10-27 ), ischemic heart disease (OR = 2.2, p < 2.3 × 10-76 ), and infectious and parasitic diseases (OR = 2.1, p = 1.5 × 10-73 ) showed strongest association with FD. Similar results were obtained in an analysis of self-reported conditions and use of medications from questionnaire data. Based on a genome-wide association meta-analysis of genotypes across all cohorts, FD heritability was estimated close to 5% ( hSNP2  = 0.047, p = 0.014). Genetic correlations indicate FD predisposition is shared with several other diseases and traits (rg  > 0.344), mostly overlapping with those also enriched in FD patients. Suggestive (p < 5.0 × 10-6 ) association with FD risk was detected for 13 loci, with 2 showing nominal replication (p < 0.05) in an independent cohort of 192 FD patients. CONCLUSIONS & INFERENCES: FD has a weak heritable component that shows commonalities with multiple conditions across a wide spectrum of pathophysiological domains. This new knowledge contributes to a better understanding of FD etiology and may have implications for improving its treatment.

Chicago classification version 4.0© technical review: Update on standard high-resolution manometry protocol for the assessment of esophageal motility.

The Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). A key feature of CCv.4.0 is the more rigorous and expansive protocol that incorporates single wet swallows acquired in different positions (supine, upright) and provocative testing, including multiple rapid swallows and rapid drink challenge. Additionally, solid bolus swallows, solid test meal, and/or pharmacologic provocation can be used to identify clinically relevant motility disorders and other conditions (eg, rumination) that occur during and after meals. The acquisition and analysis for performing these tests and the evidence supporting their inclusion in the Chicago Classification protocol is detailed in this technical review. Provocative tests are designed to increase the diagnostic sensitivity and specificity of HRM studies for disorders of esophageal motility. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification, decrease the proportion of HRM studies that deliver inconclusive diagnoses and increase the number of patients with a clinically relevant diagnosis that can direct effective therapy. Another aim in establishing a standard manometry protocol for motility laboratories around the world is to facilitate procedural consistency, improve diagnostic reliability, and promote collaborative research.

Defecatory urge increases cognitive control and intertemporal patience in healthy volunteers.

BACKGROUND: Past research has demonstrated that moderate urge to urinate improves inhibitory control, specifically among participants with higher behavioral inhibition sensitivity (BIS). The effect was absent when the urge exceeded intolerable level. The present research examines whether rectal distension-induced urge to defecate has similar effects. METHODS: The moderate and high defecatory urge were induced by rectal distension in healthy volunteers (n = 35), while they completed Stroop task and monetary delay discounting task. The difference of average reaction time between incongruent and congruent trials in the Stroop task (Stroop interference) and the preference for larger-later rewards in the delay discounting task were the primary outcomes. KEY RESULTS: Participants with high BIS (n = 17) showed greater ability to inhibit their automatic response tendencies, as indexed by their Stroop interference, under moderate urge relative to no urge (128 ± 41 ms vs 202 ± 37 ms, t64  = 2.07; P = 0.021, Cohen's d: 0.44), but not relative to high urge (154 ± 45 ms, t64  = 1.20; P = 0.12, Cohen's d: 0.30). High BIS participants also showed a higher preference for larger-later reward in the delay discounting task under high (odds ratio = 1.51 [1.02-2.25], P = 0.039) relative to no urge, but not relative to moderate urge (odds ratio = 1.02 [0.73-1.42], P = 0.91). In contrast, rectal distension did not influence performance on either of the tasks in participants with low BIS (n = 18). CONCLUSIONS AND INFERENCE: These findings may be interpreted as a "spill-over" effect of inhibition of the urge to defecate to volitional cognitive control among healthy participants with high BIS.

Factors Predictive of Treatment-Emergent Adverse Events of Prucalopride: An Integrated Analysis of Four Randomized, Double-Blind, Placebo-Controlled Trials

BACKGROUND/AIMS: This integrated analysis aimed to identify the factors associated with the most frequently reported treatment-emergent adverse events (TEAEs) in Asian and non-Asian patients with chronic constipation (CC) who receive prucalopride or placebo over 12 weeks. METHODS: Pooled data from four randomized, double-blind, placebo-controlled, multicenter, phase III studies (NCT00488137, NCT00483886, NCT00485940, and NCT01116206) on patients treated with prucalopride 2 mg or placebo were analyzed. The associations between predictors and TEAEs were evaluated based on a logistic regression model. RESULTS: Overall, 1,821 patients (Asian, 26.1%; non-Asian, 73.9%) were analyzed. Prucalopride treatment was significantly associated with diarrhea, headache, and nausea (p<0.001), but not with abdominal pain, compared with placebo. Differences in the prevalence of TEAEs between prucalopride and placebo decreased greatly after the first day of treatment. Compared with non-Asians, Asians were more likely to experience diarrhea and less likely to develop abdominal pain, headache, and nausea. Prior laxative use, CC duration, and body weight were not predictive of any of these TEAEs. CONCLUSIONS: Prucalopride treatment was positively associated with diarrhea, headache, and nausea. Asian patients tended to have a higher frequency of diarrhea but lower frequencies of headache, abdominal pain, and nausea compared with non-Asians.

Factors Predictive of Treatment-Emergent Adverse Events of Prucalopride: An Integrated Analysis of Four Randomized, Double-Blind, Placebo-Controlled Trials

BACKGROUND/AIMS: This integrated analysis aimed to identify the factors associated with the most frequently reported treatment-emergent adverse events (TEAEs) in Asian and non-Asian patients with chronic constipation (CC) who receive prucalopride or placebo over 12 weeks. METHODS: Pooled data from four randomized, double-blind, placebo-controlled, multicenter, phase III studies (NCT00488137, NCT00483886, NCT00485940, and NCT01116206) on patients treated with prucalopride 2 mg or placebo were analyzed. The associations between predictors and TEAEs were evaluated based on a logistic regression model. RESULTS: Overall, 1,821 patients (Asian, 26.1%; non-Asian, 73.9%) were analyzed. Prucalopride treatment was significantly associated with diarrhea, headache, and nausea (p<0.001), but not with abdominal pain, compared with placebo. Differences in the prevalence of TEAEs between prucalopride and placebo decreased greatly after the first day of treatment. Compared with non-Asians, Asians were more likely to experience diarrhea and less likely to develop abdominal pain, headache, and nausea. Prior laxative use, CC duration, and body weight were not predictive of any of these TEAEs. CONCLUSIONS: Prucalopride treatment was positively associated with diarrhea, headache, and nausea. Asian patients tended to have a higher frequency of diarrhea but lower frequencies of headache, abdominal pain, and nausea compared with non-Asians.

Effect of Prucalopride in the Treatment of Chronic Constipation in Asian and Non-Asian Women: A Pooled Analysis of 4 Randomized, Placebo-controlled Studies

BACKGROUND/AIMS: To compare the efficacy and safety of prucalopride, a novel selective high-affinity 5-hydroxytryptamine type 4 receptor agonist, versus placebo, in Asian and non-Asian women with chronic constipation (CC). METHODS: Data of patients with CC, receiving once-daily prucalopride 2-mg or placebo for 12-weeks, were pooled from 4 double-blind, randomized, phase-III trials (NCT00488137, NCT00483886, NCT00485940 and NCT01116206). The efficacy endpoints were: average of > or = 3 spontaneous complete bowel movements (SCBMs)/week; average increases of > or = 1 SCBMs/week; and change from baseline in each CC-associated symptom scores (bloating, abdominal pain, hard stool and straining). RESULTS: Overall, 1,596 women (Asian [26.6%], non-Asian [73.4%]) were included in this analysis. Significantly more patients in the prucalopride group versus placebo experienced an average of > or = 3 SCBMs/week in Asian (34% vs. 11%, P or = 1 SCBMs/week from baseline was significantly higher in the prucalopride group versus placebo among both Asian (57.4% vs. 28.3%, P < 0.001) and non-Asian (45.3% vs. 24.0%, P < 0.001) subgroups. The difference between the subgroups was not statistically significant. Prucalopride significantly reduced the symptom scores for bloating, hard stool, and straining in both subgroups. CONCLUSIONS: Prucalopride 2-mg once-daily treatment over 12-weeks was more efficacious than placebo in promoting SCBMs and improvement of CC-associated symptoms in Asian and non-Asian women, and was found to be safe and well-tolerated. There were numeric differences between Asian and non-Asian patients on efficacy and treatment emergent adverse events, which may be partially due to the overlap with functional gastrointestinal disorders in non-Asian patients.

Gastrointestinal Motility Changes and Myenteric Plexus Alterations in Spontaneously Diabetic Biobreeding Rats

BACKGROUND/AIMS: Type 1 diabetes is often accompanied by gastrointestinal motility disturbances. Vagal neuropathy, hyperglycemia, and alterations in the myenteric plexus have been proposed as underlying mechanism. We therefore studied the relationship between vagal function, gastrointestinal motiliy and characteristics of the enteric nervous system in the biobreeding (BB) rat known as model for spontaneous type 1 diabetes. METHODS: Gastric emptying breath test, small intestinal electromyography, relative risk-interval variability, histology and immunohistochemistry on antral and jejunal segments were performed at 1, 8 and 16 weeks after diabetes onset and on age-matched controls. RESULTS: We observed no consistent changes in relative risk-interval variability and gastric emptying rate. There was however, a loss of phases 3 with longer duration of diabetes on small intestinal electromyography. We found a progressive decrease of nitrergic neurons in the myenteric plexus of antrum and jejunum, while numbers of cholinergic nerve were not altered. In addition, a transient inflammatory infiltrate in jejunal wall was found in spontaneous diabetic BB rats at 8 weeks of diabetes. CONCLUSIONS: In diabetic BB rats, altered small intestinal motor control associated with a loss of myenteric nitric oxide synthase expression occurs, which does not depend on hyperglycemia or vagal dysfunction, and which is preceded by transient intestinal inflammation.

Validation of Octanoate Breath Test for Measuring Gastric Emptying in Rats

BACKGROUND/AIMS: Lack of simple and repeatable tests hampers gastric emptying studies in rats. The aim of this study was to adapt the 14C-octanoate solid gastric emptying breath test for application in rats, and to validate it against radioscintigraphic method. METHODS: After ingestion of a meal containing 3 mCi 99mTc and 2 microCi 14C-octanoate, 23 male Wistar rats were placed on a gamma camera in a airflow container. Scintigraphic images were taken at regular intervals. The amount of 14CO2 in a regularly replaced hyamine hydroxide solution, capturing CO2 in the outflow air, was counted using liquid scintillation spectrometry. 99mTc gastric retention curves and 14CO2-excretion curves were fitted to their respective data. Three rats underwent the same procedures after administration of atropine. RESULTS: Overall Tr10% (time at which 10% of the original amount of 99mTc remained in the stomach) was 355 +/- 64 minutes; Te90% (time at which 90% of total amount of 14CO2 was excreted) was 325 +/- 106 minutes. Their correlation coefficient was 0.71, R-square 0.50 and P < 0.005. Tr1/2 (50% of original amount of 99mTc remained) was 124 +/- 28 minutes; Te1/2 (50% of total amount of 14CO2 excreted) 114 +/- 32 minutes. Their correlation coefficient was 0.83 with R-square of 0.69 and P < 0.00005. In 12 immobilized animals correlation was even better: correlation coefficient 0.84; R-square 0.71 and P < 0.001 (Tr10% was 388 +/- 117 minutes; Te90% 532 +/- 219 minutes; Tr1/2 of 165 +/- 54 minutes; Te1/2 of 175 +/- 67 minutes). Atropine significantly lengthened all emptying times: 904 +/- 307 and 1461 +/- 684 minutes for Tr10% and Te90%, respectively; and 432 +/- 117 minutes for Tr1/2 and 473 +/- 190 minutes for Te1/2. CONCLUSIONS: We adapted and validated the 14C-octanoate gastric emptying breath test for application in rats.

Nocturnal Gastroesophageal Reflux Revisited by Impedance-pH Monitoring

BACKGROUND/AIMS: Impedance-pH monitoring allows detailed characterization of gastroesophageal reflux and esophageal activity associated with reflux. We assessed the characteristics of nocturnal reflux and esophageal activity preceding and following reflux. METHODS: Impedance-pH tracings from 11 healthy subjects and 76 patients with gastroesophageal reflux disease off acid-suppressive therapy were analyzed. Characteristics of nocturnal supine reflux, time distribution and esophageal activity seen on impedance at 2 minute intervals preceding and following reflux were described. RESULTS: Patients had more nocturnal reflux events than healthy subjects (8 [4-12] vs 2 [1-5], P = 0.002), with lower proportion of weakly acidic reflux (57% [35-78] vs 80% [60-100], P = 0.044). Nocturnal reflux was mainly liquid (80%) and reached the proximal esophagus more often in patients (6% vs 0%, P = 0.047). Acid reflux predominated in the first 2 hours (66%) and weakly acidic reflux in the last 3 hours (70%) of the night. Most nocturnal reflux was preceded by aboral flows and cleared by short lasting volume clearance. In patients, prolonged chemical clearance was associated with less esophageal activity. CONCLUSIONS: Nocturnal weakly acidic reflux is as common as acid reflux in patients with gastroesophageal reflux disease, and predominates later in the night. Impedance-pH can predict prolonged chemical clearance after nocturnal acid reflux.

Duodenal Implications in the Pathophysiology of Functional Dyspepsia

Functional dyspepsia (FD) is a heterogeneous disorder associated with diverse pathophysiologic mechanisms. Studies have shown duodenal implications in the pathophysiology of FD. Duodenal hypersensitivity to acid, increased duodenal acid exposure, and abnormal responses to duodenal lipids or released cholecystokinin have been observed in patients with FD. Moreover, there is evidence indicating duodenal immune activation in FD. Alterations in the number of duodenal eosinophils or intraepithelial lymphocytes have been reported in a subset of FD patients, particularly in patients with post-infectious FD. Whether these abnormalities in the duodenum play a crucial role in the generation of dyspeptic symptoms needs to be elucidated. Further investigations on the relationship between duodenal abnormalities and well-known pathophysiologic mechanisms of FD are required. Furthermore, the causative factors related to the development of duodenal abnormalities in FD warrant further study.

Gastroparesis: Current Concepts and Management

Delayed gastric emptying in the absence of mechanical obstruction is referred to as gastroparesis. Symptoms that are often attributed to gastroparesis include postprandial fullness, nausea, and vomiting. Although tests of gastric motor function may aid diagnostic labeling, their contribution to determining the treatment approach is often limited. Although clinical suspicion of gastroparesis warrants the exclusion of mechanical causes and serum electrolyte imbalances, followed by empirical treatment with a gastroprokinetic such as domperidone or metoclopramide, evidence that these drugs are effective for patients with gastroparesis is far from overwhelming. In refractory cases with severe weight loss, invasive therapeutics such as inserting a feeding jejunostomy tube, intrapyloric injection of botulinum toxin, surgical (partial) gastrectomy, and implantable gastric electrical stimulation are occasionally considered.