Optimizing the Use of Linaclotide in Patients with Constipation-Predominant Irritable Bowel Syndrome: An Expert Consensus Report

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic or recurrent abdominal pain in association with defecation or a change in bowel habits. A predominant disorder of bowel habits, IBS is classified into three main subtypes: constipation-predominant IBS (IBS-C), diarrhea-predominant IBS (IBS-D) and IBS alternating between constipation and diarrhea (IBS-M). Linaclotide is a first-in-class, oral, once-daily guanylate cyclase-C receptor agonist (GC-CA) that is licensed for the symptomatic treatment of moderate-to-severe IBS-C in adults. This review aims to facilitate and optimize clinical practices, establishing common guidelines to monitor patients with IBS-C that are treated with linaclotide.

METHODS

A group of experts in functional digestive disorders was convened to review the efficacy and safety of linaclotide and to develop an updated consensus report for the treatment of patients with IBS-C. A search was performed for English, French and Spanish language articles in PubMed. On the basis of the articles identified, an initial document was drafted addressing different issues frequently raised by general practitioners and GI specialists that are related to the prescription, efficacy and safety of linaclotide. This document was then reviewed and modified by the expert panel until a final text was agreed upon and validated.

RESULTS

Based on the evidence, the panel addressed the following recommendations: (1) Linaclotide is indicated for the treatment of moderate to severe IBS-C in adults; (2) it is recommended that patients take linaclotide continuously and not sporadically; (3) patients should be warned about the risk of diarrhea and given choices concerning how to deal with this possible side effect; (4) the absence of tachyphylaxis or potential risks implies that linaclotide treatment can be maintained for long periods of time.

CONCLUSIONS

This document seeks to lay down a set of recommendations and to identify key issues that may be useful for the clinical management of IBS-C patients treated with linaclotide.

Characteristics of primary care processes for the treatment of faecal incontinence in an urban area

AIM

In this study, we investigated the adequacy of the healthcare response systems to detect and treat faecal incontinence in patients in the primary care areas (PCAs) in a core urban area of Barcelona.

METHOD

Patients with a diagnosis of faecal incontinence in the study area were identified from the electronic register of diagnostic codes, and from a manual review of electronic medical records of a random sample of the study population. The remaining variables were obtained through a structured telephone interview.

RESULTS

In the study population (n = 65,023) with a previously estimated prevalence of faecal incontinence of 13% [95% confidence interval (CI) 10-17%], 68 cases of faecal incontinence were detected by the health care system (prevalence: 0.10%; 95% CI, 0.08-0.13). Of these, 39 patients (68% women, 68 ± 18 years of age) were interviewed: 18 (46%) reported symptoms lasting for longer than 5-10 years and 20 (51%) had waited for more than 5 years before seeking medical advice. Only 8 (18%) had received any treatment for faecal incontinence, and 18 (46%) reported persistent faecal incontinence at the time of the interview (Vaizey severity score 13 ± 4/24).

CONCLUSION

The detection and treatment of faecal incontinence is insufficient in primary care services. Strategies to correct this are needed.

A prospective multicentre study to investigate percutaneous tibial nerve stimulation for the treatment of faecal incontinence

AIM

Percutaneous tibial nerve stimulation (PTNS) is a minimal invasive treatment that can be performed in the outpatient clinic. This is a pilot study to investigate PTNS in the treatment of faecal incontinence.

METHOD

  Percutaneous tibial nerve stimulation was performed by insertion of a needle electrode near the posterior tibial nerve. Patients were treated twice a week. Evaluation of faecal incontinence and quality of life was performed at baseline, 6 weeks, 3 months, 6 months and 1 year. Quality of life was estimated using SF-36 and FIQL questionnaires.

RESULTS

A total of 22 patients were included. The mean age was 60.4 ± 11.7 years. After 6 weeks, 18 continued the treatment; 13 patients had a > 50% decrease in incontinence episodes. Overall incontinence episodes fell from 19.6 ± 21.0 at baseline to 9.9 ± 15.5 (P = 0.082) at 6 weeks and to 3.6 ± 4.8 (P = 0.029) at 1 year. Postponement time and quality of life increased significantly during follow up.

CONCLUSION

Percutaneous tibial nerve stimulation is simple and can be used in the outpatient setting. Good results can be obtained and sustained during maintenance treatment.

[Endoanal ultrasound findings in patients with faecal incontinence using a scoring system]

INTRODUCTION

The main aim of the study was to apply a severity classification of sphincter lesions detected by endoanal ultrasound using Starck score in patients who suffered faecal incontinence.

MATERIAL AND METHOD

Data were analysed on 133 patients with faecal incontinence. Those in whom anal sphincter lesions were detected by endoanal ultrasound are described and their corresponding scores according to Starck classification calculated. This system scores severity of detected sphincter lesions from 0 to 16, involving the three axes of the anal canal. Patient demographic characteristics and anorectal manometry results were also analysed. The relationship between this score, patient gender and age, and anorectal manometric results were also analysed.

RESULTS

A total of 83 (62.4%) patients had some type of anal sphincter lesion. The presence of sphincter defects was not related to gender (P=0.172), although it did correlate with younger ages (P=0.028). The severity of anal sphincter damage by Starck score did not show significant correlation to gender (P=0.327) or to the age (P=0.350) of patients. However, a significant correlation was detected between Starck score and anal resting pressure (P=0.008) or anorectal squeeze pressure (P=0.011).

CONCLUSIONS

The presence of anal sphincter injuries could be well defined by Starck score in patients with faecal incontinence. Severity of damage scored by Starck correlated with anorectal manometric results.

High body mass alters colonic sensory-motor function and transit in humans

There is increased prevalence of abdominal pain and diarrhea and decreased gastric sensation with increased body mass index (BMI). Our hypothesis is that increased BMI is associated with increased colonic motility and sensation. The study aim was to assess effect of BMI on colonic sensory and motor functions and transit. We used a database of colonic tone, compliance, and perception of distensions measured by intracolonic, barostat-controlled balloon, and gastrointestinal transit was measured by validated scintigraphy in healthy obese and nonobese subjects. Regression analysis was applied to assess the association of BMI with colonic sensory and motor functions. We included adjustments for sex differences, age, height, balloon volumes during distension, and psychological stress. Among 165 participants (87 women, 78 men), increased BMI was associated with decreased colonic compliance (P < 0.006, adjusted), decreased pain rating during distensions (P = 0.02, adjusted), and a higher threshold for pain (P = 0.042, adjusted). Sensation for gas, colonic tone, and contraction after meal ingestion were not significantly associated with BMI. Transit was assessed in 72 participants (41 women, 31 men); colonic transit was faster with BMI >30 kg/m(2) (P = 0.003 unadjusted, P = 0.08 adjusted for gender). In conclusion, BMI >25 kg/m(2) is associated with decreased colonic compliance and pain sensation; colonic transit is accelerated particularly with BMI >30 kg/m(2) in women. These data suggest that colonic dysfunction may contribute to diarrhea, but the cause of increased abdominal pain in obesity is not explained by the studies of colonic sensation and requires further study of afferent, spinal, and central mechanisms.

[Gastric emptying and functional dyspepsia]

Dyspeptic syndrome includes symptoms such as upper abdominal pain, nausea and/or vomiting. These symptoms are common to highly diverse processes such as duodenal ulcer, pancreatitis and even intestinal ischemia, among many others. However, most patients who consult for this syndrome do not have any of these well known processes. New mechanisms have been proposed that could explain the symptoms presented by these patients. Among these mechanisms are those relating to an alteration of normal gastroduodenal motor function, such as alterations of gastric compliance, antral distension, gastric accommodation to anomalous ingestion, and alterations of gastric emptying. The present review evaluates the role of gastric emptying in producing dyspeptic symptoms according to the evidence available to date. We discuss gastric emptying in patients with functional or idiopathic dyspepsia compared with that in the healthy population, the correlation between gastric emptying and dyspeptic symptoms, and the response of dyspeptic symptoms to the prokinetic therapies carried out to date.

Effect of gastric volume or emptying on meal-related symptoms after liquid nutrients in obesity: a pharmacologic study

BACKGROUND & AIMS

Altered postprandial satiation influences food intake in obesity. The aim of this study was to evaluate the contribution of gastric motor functions to intra- and postprandial symptoms in obese, otherwise healthy, people.

METHODS

In a randomized, parallel-group, double-blind design, 40 obese (body mass index>30 kg/m2) healthy volunteers (n=10/group) received intravenous saline (placebo), atropine (.02 mg/kg), or erythromycin (1 or 3 mg/kg) to alter gastric volume and emptying after liquid nutrient meals, measured by validated imaging methods. The nutrient drink test assessed the volume ingested at maximum satiation, and intra- and early postprandial symptoms. Relationships between gastric motor functions, meal size, and symptoms were assessed by using multiple regression. Circulating levels of candidate upper-gut hormones involved in satiation were measured.

RESULTS

Relative to placebo, atropine retarded gastric emptying and increased gastric volumes; erythromycin accelerated gastric emptying and reduced gastric volumes during fasting. Although similar maximal tolerated volumes were recorded across treatments, intra- and immediate postprandial symptoms were increased by these perturbations, particularly nausea and bloating. Upper-gut hormonal profiles generally reflected changes in gastric emptying. Regression analysis showed that fasting predrug gastric volume was a significant predictor of intra- and postprandial bloating. Change in gastric volume postdrug or postmeal did not contribute additionally to predicting intra- or postprandial symptoms. There was significant (negative) association between gastric emptying and fullness score, and significant (positive) association with hunger score 30 minutes postprandially.

CONCLUSIONS

In obese individuals, fasting gastric volumes and gastric emptying, but not postprandial gastric volumes, were associated with intra- and postprandial symptoms. Understanding the determinants of gastric volume may provide insights on mechanisms controlling satiation.

Visceral hypersensitivity

Visceral hypersensitivity is considered one of the causes of functional gastrointestinal disorders. The objectives of this review are to provide a practical description of neuroanatomy and physiology of gut sensation, to describe the diverse tests of visceral sensation and the potential role of brain imaging to further our understanding of visceral sensitivity in health and disease. Changes in motor function in the gut may influence sensory levels, eg, during contractions or as a result of changes in viscus compliance. New insights on sensory end organs, such as intraganglionic laminar endings, and basic neurophysiologic studies showing afferent firing during changes in stretch rather than tension illustrate the importance of different types of stimuli, not just tension, to stimulate afferent sensation. These insights provide the basis for understanding visceral sensation in health and disease, which will be extensively discussed in subsequent articles.

Contributions of gastric volumes and gastric emptying to meal size and postmeal symptoms in functional dyspepsia

BACKGROUND & AIMS

The aim was to assess relative contributions of gastric volumes (GV) and gastric emptying (GE) to meal size and postprandial symptoms in patients with functional dyspepsia.

METHODS

Patients with chronic upper gastrointestinal symptoms were prospectively evaluated. GV during fasting and after 300 mL Ensure was measured with 99m Tc-single-photon emission computed tomography imaging and solid GE (99m Tc-egg) by scintigraphy. Maximum tolerated volume (MTV) and symptoms were measured after Ensure challenge.

RESULTS

Of 57 adult patients evaluated, 39 (23 women, 16 men) met Rome II criteria for functional dyspepsia and had no other diagnosis to account for dyspepsia. The most frequent symptoms were abdominal pain (90%), pain predominantly after meals (76%), nausea (85%), and early fullness after meals (79%). Relative to established laboratory normal values, MTV was abnormal in 82%, aggregate symptom score >209 in 72%, GE (at 1 hour) accelerated in 41%, GE (at 4 hours) delayed in 41%, and postmeal GV reduced in 52%. Lower body mass was associated with lower MTV and higher postchallenge symptoms. Lower fasting (not postprandial) GV and faster GE were independent predictors of lower MTV, explaining 18% of the variance after adjusting for body weight (32% of variance). GE was an independent predictor of postchallenge symptoms (10% of variance) after adjusting for volume ingested (10%), age (20%), and weight (10%).

CONCLUSIONS

In adults with functional dyspepsia seen in a tertiary referral practice, decreased meal size and postmeal symptoms are associated with low fasting GV and faster GE. These data provide physiologic targets for ameliorating symptoms of functional dyspepsia.

Obesity is associated with increased risk of gastrointestinal symptoms: a population-based study

OBJECTIVES

Perception of sensations arising from the gastrointestinal tract may be diminished in obese subjects and thus facilitate overeating. Alternatively, excess food intake may cause gastrointestinal (GI) symptoms in obese patients. We evaluated the relationship between body mass index (BMI) and specific GI symptoms in the community.

METHODS

Residents of Olmsted County, MN were selected at random to receive by mail one of two validated questionnaires. The association of reported GI symptoms with BMI (kg/m(2)) was assessed using a logistic regression analysis adjusting for age, gender, psychosomatic symptom score, and alcohol and tobacco use.

RESULTS

Response rate was 74% (1,963 of 2,660). The prevalence of obesity (BMI > or = 30 kg/m(2)) was 23%. There was a positive relationship between BMI and frequent vomiting (p= 0.02), upper abdominal pain (p= 0.03), bloating (p= 0.002), and diarrhea (p= 0.01). The prevalence of frequent lower abdominal pain, nausea, and constipation was increased among obese (BMI > or = 30 kg/m(2)) compared to normal weight participants, however, no significant association was found between BMI and these symptoms.

CONCLUSIONS

In the community, increasing BMI is associated with increased upper GI symptoms, bloating, and diarrhea. Clarification of the cause-and-effect relationships and the mechanisms of these associations require further investigation.

Effect of oral CCK-1 agonist GI181771X on fasting and postprandial gastric functions in healthy volunteers

CCK influences satiation and gastric and gallbladder emptying. GI181771X is a novel oral CCK-1 agonist; its effects on gastric emptying of solids, accommodation, and postprandial symptoms are unclear. Effects of four dose levels of the oral CCK-1 agonist GI181771X and placebo on gastric functions and postprandial symptoms were compared in 61 healthy men and women in a randomized, gender-stratified, double-blind, double-dummy placebo-controlled, parallel group study. Effects of 0.1, 0.5, and 1.5 mg of oral solution and a 5.0-mg tablet of GI181771X on gastric emptying of solids by scintigraphy, gastric volume by (99m)Tc-single photon emission computed tomographic imaging, maximum tolerated volume of Ensure, and postprandial nausea, bloating, fullness, and pain were studied. On each of 3 study days, participants received their randomly assigned treatment. Adverse effects and safety were monitored. There were overall group effects of GI181771X on gastric emptying (P < 0.01) and fasting and postprandial volumes (P = 0.036 and 0.015, respectively). The 1.5-mg oral solution of GI181771X significantly delayed gastric emptying of solids (P < 0.01) and increased fasting (P = 0.035) gastric volumes without altering postprandial (P = 0.056) gastric volumes or postprandial symptoms relative to placebo. The effect of the 5.0-mg tablet on gastric emptying of solids did not reach significance (P = 0.052). Pharmacokinetic profiles showed the highest area under the curve over 4 h for the 1.5-mg solution and a similar area under the curve for the 0.5-mg solution and 5-mg tablet. Adverse effects were predominantly gastrointestinal and occurred in a minority of participants. GI181771X delays gastric emptying of solids and exhibits an acceptable safety profile in healthy participants. CCK-1 receptors can be modulated to increase fasting gastric volume.

Functional dyspepsia: drugs for new (and old) therapeutic targets

The therapeutic management of functional dyspepsia remains a major challenge for the gastroenterologist. Current therapies available are based on putative underlying pathophysiologic mechanisms, including gastric acid sensitivity, slow gastric emptying and Helicobacter pylori infection, but only a small proportion of patients achieve symptomatic benefit from these therapeutic approaches. Relatively novel mechanistic concepts under testing include impaired gastric accomodation, visceral hypersensitivity, and central nervous system dysfunction. Serotonergic modulators (e.g. the 5-HT4 agonist tegaserod, the 5-HT3 antagonist alosetron and the 5-HT1P agonist sumatriptan), CCK-1 antagonists (e.g. dexloxiglumide), opioid agonists (e.g. asimadoline), N-methyl-D-aspartate (NMDA) receptor antagonists (e.g dextromethorphan), neurokinin antagonists (e.g. talnetant), capsaicin-like agents and antidepressants are among the agents currently under investigation. It seems unlikely, however, that targeting a single mechanism with an individual drug will result in complete symptom remission in most cases.

The role of pelvic floor dysfunction and slow colonic transit in adolescents with refractory constipation

OBJECTIVE

Although pelvic floor dysfunction (PFD) is recognized as a cause of refractory constipation in adults, this diagnosis is not frequently considered in children and adolescents with refractory constipation. The purpose of this study was to examine the symptoms and colonic transit in adolescents with constipation evaluated for a disorder in pelvic floor function.

METHODS

Adolescents with refractory constipation who had undergone anorectal manometry (ARM) and balloon expulsion test (BET) were identified by retrospective review of records. Initial symptoms and the clinician's assessment were used to categorize patients by pediatric Rome II criteria, that is, functional constipation (FC), constipation-predominant irritable bowel syndrome (C-IBS) or functional fecal retention (FFR). Results of scintigraphic colonic transit studies were evaluated. A chi2 test was used to assess the association between individual clinical symptoms and Rome II criteria.

RESULTS

Sixty-seven adolescents underwent evaluation of pelvic floor function by tests for PFD: BET was abnormal in 42%. There was no underlying disease or alternative diagnosis to account for the constipation in these patients. Among the 41 patients who also underwent scintigraphic colonic transit, 30% had slow transit constipation and 12% had both slow colonic transit and abnormal BET. Patients classified as C-IBS were more likely to report weight loss (p = 0.03), bloating (p = 0.04), and incomplete rectal evacuation (p = 0.03).

CONCLUSION

Abnormal pelvic floor function and delayed colonic transit are demonstrable as single or combined problems in adolescents with refractory constipation.

Treatment of Functional Dyspepsia

Functional dyspepsia is a common chronic condition. It can have a major impact on quality of life and remains a large burden on healthcare resources. Its underlying mechanisms are not fully understood and therapies are mainly empirical. In this review, we summarize the best evidence on available therapeutic interventions in functional dyspepsia. Helicobacter pylori eradication, for those infected, is likely a safe and cost-effective strategy but benefits only a minority. Antisecretory agents such as proton-pump inhibitors and histamine-2 receptor antagonists have shown some benefit and are recommended as the first-line option in the absence of H. pylori infection. There is a lack of strong evidence of benefit from prokinetic agents, and cisapride, the most studied agent, is largely unavailable. Antidepressants need to be adequately tested in functional dyspepsia, but both psychotherapy and hypnotherapy interventions have shown promising results. Herbal therapies need further study in these patients. 5-Hydroxytryptamine3 (5-HT(3)) and 5-HT(4) receptor antagonists, and cholecystokinin type A and neurokinin receptor antagonists remain promising emerging therapies.

Independent influences of body mass and gastric volumes on satiation in humans

BACKGROUND & AIMS

We assessed the association of body mass and gastric volumes (fasting and postprandial) with satiation and postprandial symptoms.

METHODS

Healthy obese and nonobese subjects underwent measurement of caloric intake at maximum satiation; postprandial symptoms were measured with visual analogue scales 30 minutes after a meal. Gastric volume during fasting and after 300 mL of Ensure was measured with technetium-99m single-photon emission computed tomography imaging. We used multiple regression analysis to assess the associations among variables.

RESULTS

Among 134 participants (81 women and 53 men), the median age was 26 years (range, 12-58 years), and the median body mass index was 24 kg/m(2) (range, 17-48 kg/m(2)). Increased body mass index, but not height, was associated with delayed satiation (P < 0.003, adjusted for sex). Overweight and obese subjects ingested, on average, 225 +/- 57 more kilocalories (945 +/- 239 kJ) at maximum satiation compared with normal weight individuals. Increased fasting gastric volume was not associated with body mass index or height, but it was significantly associated with delayed satiation (P = 0.001, adjusted for body mass index and sex). An increase of 50 mL in the fasting gastric volume was associated with 114 +/- 32 kcal (479 +/- 134 kJ) more ingested at maximum satiation. Increased body mass index was associated with lower fullness scores 30 minutes after a meal (P = 0.0012, adjusted for sex and volume of Ensure ingested). In contrast, scores of postprandial bloating and pain were higher with increased body mass index (both P < 0.05, adjusted for sex and volume of Ensure ingested).

CONCLUSIONS

Greater body mass index and fasting gastric volume are associated with reduced satiation. Increased body mass index or height was not associated with greater gastric volumes.

Functional dyspepsia, upper gastrointestinal symptoms, and transit in children

OBJECTIVE

To assess the prevalence of abnormal gastric emptying and small bowel transit in children with functional dyspepsia at a tertiary care center, and the relationship between abnormal gastric and small bowel transit and symptoms in pediatric patients with functional gastrointestinal disorders.

STUDY DESIGN

Patients were selected by a cross-sectional chart review based on the following inclusion criteria: (1) completion of scintigraphic study of the gastric emptying of solids at 2 hours (GE2), 4 hours (GE4), and small bowel transit at 6 hours (SBT) using a standardized egg meal labeled with 99mTechnetium sulfur colloid, and (2) gastrointestinal (GI) complaints without mucosal or organic disease. Logistic regression analysis was used to assess the association between the presence of upper GI symptoms, and each parameter of gastric and small bowel transit.

RESULTS

Children with upper GI symptoms (n=96) were identified. Among 57 children with functional dyspepsia, 40% had slow SBT. Fast GE at 4 hours, and slow SBT were independently associated with bloating. Children with fast SBT were less likely to report abdominal pain.

CONCLUSION

Incorporating assessments of gastric and small bowel transit may be useful in the evaluation of pediatric patients with upper GI symptoms and functional dyspepsia.

Effects of asimadoline, a kappa-opioid agonist, on satiation and postprandial symptoms in health

AIM

To evaluate the effect of single administrations of asimadoline, a kappa-opioid agonist, on satiation volume, postprandial symptoms and gastric volumes.

METHODS

Healthy subjects received oral placebo, or 0.5 or 1.5 mg asimadoline in a randomized, double-blind fashion 1 h prior to testing. We assessed effects on the volume of Ensure to achieve full satiation and postprandial symptoms 30 min after meal, and on gastric volume (fasting and postprandial) measured by 99mTc-single photon emission tomography (SPECT) imaging.

RESULTS

Thirteen healthy subjects were studied in each treatment arm. Compared to placebo, asimadoline 0.5 mg decreased postprandial fullness (P = 0.027) without affecting the volume ingested at full satiation (P = 0.6). Asimadoline 1.5 mg decreased satiation during meal, allowing increased satiation volumes (P = 0.008) and tended to decrease postprandial fullness (P = 0.067), despite higher volumes ingested. There was a significant treatment-gender interaction in the effect of asimadoline on gastric volumes (P < 0.05). Asimadoline 0.5 mg (not 1.5 mg) increased fasting (P = 0.047) and postprandial (P = 0.009) gastric volumes in females but decreased fasting volumes in males (P = 0.008). The effect of asimadoline on gastric volume did not explain the effect observed on satiation volume (P = 0.371) or postprandial fullness (P = 0.399).

CONCLUSION

A single oral administration of asimadoline decreases satiation and postprandial fullness in humans independently of its effects on gastric volume.

Meta-analysis: the relationship between Helicobacter pylori infection and gastro-oesophageal reflux disease

BACKGROUND

The relationship between Helicobacter pylori infection and its treatment and gastro-oesophageal reflux disease (GERD) is controversial.

AIMS

To establish if H. pylori infection is associated with the presence of GERD and if anti-H. pylori treatment leads to de novo GERD or rebound/exacerbation of GERD.

METHODS

A search of MEDLINE and EMBASE databases was made. Pooled odds ratios (OR) were calculated for de novo GERD and rebound/exacerbated GERD after anti-H. pylori therapy in case-control studies and in therapeutic trials.

RESULTS

Fourteen case-control studies and 10 clinical trials were included. Among case-control studies, pooled OR for the association between H. pylori negative status and GERD was 1.34 [95% confidence interval (CI) 1.15-1.55]. Among therapeutic trials, pooled OR for the association anti-H. pylori therapy - GERD was 2.54 (95% CI 1.92-3.37). The OR for de novo GERD was 3.25 (95% CI 2.09-5.33), and for rebound/exacerbated GERD was 2.39 (95% CI 1.75-3.34). Associations were higher among Asian studies than among North American and European studies.

CONCLUSIONS

This meta-analysis shows significant association between absence of H. pylori infection and GERD symptoms, and a positive association between anti-H. pylori therapy and occurrence of both de novo and rebound/exacerbated GERD. The significance of these associations appears to have been inflated by the effect of single trials and by geographical variations.

Effects of glucagon-like peptide-1 and feeding on gastric volumes in diabetes mellitus with cardio-vagal dysfunction

Glucagon-like peptide-1 (GLP-1) increases gastric volume in humans possibly through the vagus nerve. Gastric volume response to feeding is preserved after vagal denervation in animals. We evaluated gastric volume responses to GLP-1 and placebo in seven diabetic patients with vagal neuropathy in a crossover study. We also compared gastric volume response to feeding in diabetes with that in healthy controls. We measured gastric volume using SPECT imaging. Data are median (interquartile range). In diabetic patients, GLP-1 did not increase gastric volume during fasting [5 mL (-3; 30)] relative to placebo [4 mL (-14; 50) P = 0.5], or postprandially [Delta postprandial minus fasting volume 469 mL (383; 563) with GLP-1 and 452 mL (400; 493) with placebo P = 0.3]. Change in gastric volume over fasting in diabetic patients on placebo was comparable to that of healthy controls [452 mL (400; 493)], P = 0.5. In contrast to effects in health, GLP-1 did not increase gastric volume in diabetics with vagal neuropathy, suggesting GLP-1's effects on stomach volume are vagally mediated. Normal gastric volume response to feeding in diabetics with vagal neuropathy suggests that other mechanisms compensate for vagal denervation.

Systematic review and meta-analysis: does gall-bladder ejection fraction on cholecystokinin cholescintigraphy predict outcome after cholecystectomy in suspected functional biliary pain?

BACKGROUND

Patients with suspected functional biliary pain often undergo cholecystectomy if a decreased gall-bladder ejection fraction (GBEF <35%) is demonstrated by cholecystokinin cholescintigraphy. However, the validity of GBEF in predicting which patients will have symptomatic relief following cholecystectomy is unclear.

AIM

To determine whether patients with suspected functional biliary pain with decreased GBEF have a better symptomatic outcome after cholecystectomy than those with normal GBEF.

METHODS

Systematic review and meta-analysis of the published literature through MEDLINE and EMBASE databases.

RESULTS

We included nine studies with a total of 974 patients with suspected functional biliary pain; 362 patients underwent cholecystectomy. Most studies assessed outcome by direct patient interview. Mean ages across the studies ranged from 35 to 47 years; 78% of all patients were female. Mean duration of follow-up after surgery ranged from 1 to 2.5 years. After cholecystectomy, 94% of the patients with reduced GBEF had a positive outcome compared to 85% among those with normal GBEF. The pooled Mantel-Haenszel odds ratio for positive outcome was 1.37 (95% confidence interval 0.56-3.34), P=0.56.

CONCLUSION

These data do not support the use of GBEF to select patients with suspected functional biliary pain for cholecystectomy. Prospective randomized trials are required if this practice is to be evidence-based.

Pseudo-obstruction in the critically ill

Intestinal pseudo-obstruction is defined as a clinical syndrome characterized by impairment of intestinal propulsion, which may resemble intestinal obstruction, in the absence of a mechanical cause. It may involve the small and/or the large bowel, and may present in acute, subacute or chronic forms. We have performed a systematic review of acute pseudo-obstruction, also referred to as Ogilvie's syndrome in the literature, and focused on proposed mechanisms, manifestations and management of post-surgery and critically ill patients who suffer from one or more underlying clinical conditions. The hallmark of the syndrome is massive intestinal distension, which is detected on clinical inspection and plain abdominal radiography. The underlying pathophysiological mechanisms are not fully understood. Therefore, treatment focuses on preventing intestinal perforation, which is associated with an average 21% mortality rate.

Pseudo-obstruction in the critically ill

Intestinal pseudo-obstruction is defined as a clinical syndrome characterized by impairment of intestinal propulsion, which may resemble intestinal obstruction, in the absence of a mechanical cause. It may involve the small and/or the large bowel, and may present in acute, subacute or chronic forms. We have performed a systematic review of acute pseudo-obstruction, also referred to as Ogilvie's syndrome in the literature, and focused on proposed mechanisms, manifestations and management of post-surgery and critically ill patients who suffer from one or more underlying clinical conditions. The hallmark of the syndrome is massive intestinal distension, which is detected on clinical inspection and plain abdominal radiography. The underlying pathophysiological mechanisms are not fully understood. Therefore, treatment focuses on preventing intestinal perforation, which is associated with an average 21% mortality rate.

Effects of venlafaxine, buspirone, and placebo on colonic sensorimotor functions in healthy humans

BACKGROUND & AIMS

We have shown that venlafaxine-XR, a serotonin (5-HT) and norepinephrine reuptake inhibitor, enhanced gastric accommodation, whereas buspirone, a 5-HT(1A) receptor agonist, reduced postprandial symptoms after a fully satiating meal. Our aim was to compare the effects of venlafaxine, buspirone, and placebo on colonic sensorimotor functions in healthy adults.

METHODS

In this randomized, double-blind, parallel-group, placebo-controlled trial of 60 healthy adults, we assessed the effects of oral venlafaxine, 150 mg; buspirone, 20 mg; and placebo on colonic sensorimotor functions.

RESULTS

Venlafaxine increased colonic compliance relative to placebo; thus it decreased the intracolonic balloon pressure at half-maximum volume (P = 0.001) and altered the overall shape of the compliance curve, beta (P = 0.01). Venlafaxine also decreased fasting colonic tone (P = 0.02) and the tonic response to a meal (P = 0.003) compared with placebo; no differences in high amplitude phasic contractile events were observed. Pressure thresholds for first sensation (P = 0.1) and gas (P = 0.07) were not statistically significant with venlafaxine. The increase in pain scores per unit pressure during phasic distentions were affected by treatment (P = 0.02), with smallest changes on venlafaxine and highest on placebo. Buspirone did not significantly alter colonic compliance, tone, or sensation relative to placebo.

CONCLUSIONS

Venlafaxine alters colonic compliance and tone, and tends to reduce sensation during colonic distention in healthy humans. These data support the need for further clinical and physiologic studies of venlafaxine in colonic disorders affecting motor and possibly sensory functions.

Effects of a kappa-opioid agonist, asimadoline, on satiation and GI motor and sensory functions in humans

To compare the effects of the kappa-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.

Efficacy of alosetron in irritable bowel syndrome: a meta-analysis of randomized controlled trials

The 5HT3 receptor antagonist alosetron has been tested in several trials on irritable bowel syndrome (IBS) patients. The aim of the present meta-analysis was to determine its effect on adequate relief of pain or global improvement of symptoms in IBS patients. Six large, multicentre, randomized, placebo-controlled trials fulfilled pre-set criteria for high quality and were included in the meta-analysis; 1762 patients were randomized to alosetron treatment and 1356 to placebo. Seventy-five per cent of the patients experienced diarrhoea-predominant IBS and 93% were females. The pooled odds ratio for adequate relief of pain or global symptoms improvement was 1.81 [95% confidence interval (CI) 1.57-2.10). The average number of patients needed to treat with alosetron for one patient to achieve improvement over placebo treatment was seven (95% CI 5.74-9.43). The present analysis shows that alosetron 1 mg b.i.d. positively impacts global symptoms, and pain and discomfort in non-constipated IBS female patients. One in four patients treated with alosetron may develop constipation. The efficacy of alosetron is unclear in male patients.

Manejo clínico de la seudoobstrucción aguda de colon en el enfermo hospitalizado: revisión sistemática de la bibliografía

Intestinal pseudoobstruction is a clinical syndrome characterized by impairment of intestinal propulsion, which may resemble intestinal obstruction, in the absence of a mechanical cause. It usually affects the colon but the small intestine may also be involved, and may present in acute, subacute or chronic forms. We have performed a systematic review of the acute form of pseudoobstruction, also referred to as Ogilvie's syndrome. We discuss proposed pathophysiological mechanisms, manifestations and management of this clinical condition in post-surgery and critically ill patients. The hallmark of the syndrome is massive intestinal distension, which is detected on clinical inspection and plain abdominal radiography. The underlying pathophysiological mechanisms are not fully understood. Therefore, treatment has focussed on preventing intestinal perforation, which is associated with a 21% mortality rate.

SPECT imaging of the stomach: comparison with barostat, and effects of sex, age, body mass index, and fundoplication. Single photon emission computed tomography

BACKGROUND

Impaired gastric accommodation may lead to dyspeptic symptoms. A non-invasive method using single photon emission computed tomography (SPECT) has been developed to measure gastric volumes.

AIMS AND METHODS

Our aims were: to assess the accuracy of SPECT with three dimensional image analysis to measure balloon volumes in vitro; to compare gastric barostat balloon volumes measured post-meal and post-distension with total gastric volumes measured simultaneously with SPECT; to present normal gastric volume data for healthy adults; and to compare SPECT data in health with symptomatic post-fundoplication patients.

RESULTS

In vitro balloon volumes measured by SPECT were highly accurate (R(2)=0.99). When measured simultaneously by gastric barostat and SPECT, postprandial/fasting volume ratios (2.2 (0.12) (mean (SEM)) v 2.3 (0.15), respectively; p=0.6) and post-distension volume ratios (1.4 (0.1) v1.3 (0.1); p=0.2) were highly comparable. In females, postprandial gastric volumes (675 (14) v 744 (20) ml for males; p=0.004) and changes in gastric volumes (464 (14) ml v 521 (20) ml for males; p=0.01) measured by SPECT were significantly lower than in males. No effects of age or body mass index were noted. The postprandial/fasting gastric volume ratio by SPECT was lower in post-fundoplication patients (2.7 (0.2)) than in healthy controls (3.4 (0.1); p=0.003).

CONCLUSIONS

SPECT provides a non-invasive estimate of the effect of a meal on total gastric volume that is comparable to changes in balloon volume observed with the gastric barostat. The SPECT technique is promising for investigation of gastric volumes in health and disease and the effects of pharmacological agents.

A nutrient drink test to assess maximum tolerated volume and postprandial symptoms: effects of gender, body mass index and age in health

To assess the effects of age, gender and body mass index on the maximum tolerated volume of a nutrient drink and postprandial symptoms in health. Healthy adolescents (15 M, 15 F, aged 13-17 years) and adults (15 M, 25 F, aged 19-51 years) ingested Ensure (1 kcal mL-1) at a rate of 30 mL min-1. The maximum tolerated volume was recorded. Thirty minutes later, bloating, fullness, nausea and pain were rated using visual analogue scales. The Mann-Whitney test was used for comparisons between groups using body mass index and maximum tolerated volume as covariates. Age-related differences in maximum tolerated volume were noted between adolescents and adults, and were observed in both genders. Adults had higher scores for bloating and pain, and lower scores for fullness. Gender-related differences in maximum tolerated volume were noted in the group as a whole, and separately for adolescents and adults. Females had higher scores for nausea and pain. Gender and age-related differences in the maximum tolerated volume of a nutrient drink and postprandial symptoms should be considered in future studies of upper gastrointestinal symptoms in disease. Body mass index does not appear to influence maximum tolerated volume beyond its association with age and gender.

Effect of GLP-1 on gastric volume, emptying, maximum volume ingested, and postprandial symptoms in humans

Glucagon-like peptide-1 (GLP-1) relaxes the stomach during fasting but decreases hunger and food consumption and retards gastric emptying. The interrelationships between volume, emptying, and postprandial symptoms in response to GLP-1 are unclear. We performed, in healthy human volunteers, a placebo-controlled study of the effects of intravenous GLP-1 on gastric volume using (99m)Tc-single photon emission computed tomography imaging, gastric emptying of a nutrient liquid meal (Ensure) using scintigraphy, maximum tolerated volume (MTV) of Ensure, and postprandial symptoms 30 min after MTV. The role of vagal cholinergic function in the effects of GLP-1 was assessed by human pancreatic polypeptide (HPP) response to the Ensure meal. GLP-1 increased fasting and postprandial gastric volumes and retarded gastric emptying; MTV and postprandial symptoms were not different compared with controls. Effects on postprandial gastric function were associated with reduced postprandial HPP levels. GLP-1 does not induce postprandial symptoms despite significant inhibition of gastric emptying and vagal function; this may be partly explained by the increase in postprandial gastric volume.

Noninvasive measurement of gastric accommodation in patients with idiopathic nonulcer dyspepsia

OBJECTIVES

Postprandial symptoms are associated with impaired postprandial gastric accommodation. The aims of this study were to apply a noninvasive method to measure accommodation of the entire stomach in healthy subjects and in patients with idiopathic dyspeptic symptoms, and to assess the frequency of abnormal gastric accommodation and emptying of solids in these patients.

METHODS

In 20 healthy volunteers and 32 tertiary referral patients, we used i.v. 99mTc-single photon emission computed tomography (SPECT) to measure fasting and postprandial gastric volumes; we expressed the volume response to feeding ("accommodation") as the change in gastric volume and the ratio of postprandial/fasting volumes. The stomach was identified in transaxial SPECT tomographic images using a semiautomated, intensity-based extraction algorithm. Whole gastric volumes were measured using AnalyzeAVW software. Gastric emptying in patients was measured by scintigraphy. We also assessed dyspeptic symptoms and the association with normal or reduced accommodation.

RESULTS

SPECT imaging detects the postprandial change in gastric volume ("accommodation") in health and disease. Among healthy subjects (eight men, 12 women), the postprandial/fasting gastric volume ratio was 4.9+/-1.7 (mean +/- SD; fifth through 95th percentiles 3-8, median 4.6). Thirteen (41%) patients with idiopathic nonulcer dyspepsia had reduced postprandial "accommodation." Gastric emptying was fast in four (13%), normal in 25 (78%), and slow in three (9%) patients. Both tests were normal in 50% of patients. Weight loss of >10 pounds tended to be more frequently observed in those with reduced "accommodation" (62% vs 32%, p = 0.09).

CONCLUSIONS

SPECT imaging noninvasively measures fasting and postprandial gastric volumes in humans. Half the patients with idiopathic nonulcer dyspepsia had impaired gastric accommodation or emptying. Reduced gastric "accommodation" was observed in 41% of a group with idiopathic nonulcer dyspepsia. Abnormal gastric emptying is less frequent (22%).