Gastroparesis and small bowel dysmotility in irritable bowel syndrome

Postprandial effect of gastrointestinal hormones and gastric activity in patients with irritable bowel syndrome

Altered gut regulation, including motor and secretory mechanisms, is characteristic of irritable bowel syndrome (IBS). The severity of postprandial symptoms in IBS patients is associated with discomfort and pain; gas-related symptoms such as bloating and abdominal distension; and abnormal colonic motility. The aim of this study was to assess the postprandial response, i.e., gut peptide secretion and gastric myoelectric activity, in patients with constipation-predominant IBS. The study was conducted on 42 IBS patients (14 males, 28 females, mean age 45.1 ± 15.3 years) and 42 healthy participants (16 males, 26 females, mean age 41.1 ± 8.7 years). The study assessed plasma gut peptide levels (gastrin, CCK-Cholecystokinin, VIP-Vasoactive Intestinal Peptide, ghrelin, insulin) and gastric myoelectric activity obtained from electrogastrography (EGG) in the preprandial and postprandial period (meal-oral nutritional supplement 300 kcal/300 ml). Mean preprandial gastrin and insulin levels were significantly elevated in IBS patients compared to the control group (gastrin: 72.27 ± 26.89 vs. 12.27 ± 4.91 pg/ml; p < 0.00001 and insulin: 15.31 ± 12.92 vs. 8.04 ± 3.21 IU/ml; p = 0.0001), while VIP and ghrelin levels were decreased in IBS patients (VIP: 6.69 ± 4.68 vs. 27.26 ± 21.51 ng/ml; p = 0.0001 and ghrelin: 176.01 ± 88.47 vs. 250.24 ± 84.55 pg/ml; p < 0.0001). A nonsignificant change in the CCK level was observed. IBS patients showed significant changes in postprandial hormone levels compared to the preprandial state-specifically, there were increases in gastrin (p = 0.000), CCK (p < 0.0001), VIP (p < 0.0001), ghrelin (p = 0.000) and insulin (p < 0.0001). Patients with IBS showed reduced preprandial and postprandial normogastria (59.8 ± 22.0 vs. 66.3 ± 20.2%) compared to control values (83.19 ± 16.7%; p < 0.0001 vs. 86.1 ± 9.4%; p < 0.0001). In response to the meal, we did not observe an increase in the percentage of normogastria or the average percentage slow-wave coupling (APSWC) in IBS patients. The postprandial to preprandial power ratio (PR) indicates alterations in gastric contractions; in controls, PR = 2.7, whereas in IBS patients, PR = 1.7, which was significantly lower (p = 0.00009). This ratio reflects a decrease in gastric contractility. Disturbances in the postprandial concentration of gut peptides (gastrin, insulin and ghrelin) in plasma may contribute to abnormal gastric function and consequently intestinal motility, which are manifested in the intensification of clinical symptoms, such as visceral hypersensitivity or irregular bowel movements in IBS patients.

[Functional Gastrointestinal Disorders in Patients with Inflammatory Bowel Disease]

With emerging more effective drugs, the therapeutic goal of inflammatory bowel disease (IBD) has progressed from clinical remission to mucosal healing. Although the inflammation could be controlled more effectively than before, symptoms such as abdominal pain and bowel habit change is still bothersome to some IBD patients. Recently, these "refractory functional gastrointestinal symptoms" in quiescent IBD patients has been paid more attention. The pathophysiology could be multifactorial with genetics, change in gut motility associated with post inflammatory condition, increased permeability, impaired colorectal function, visceral hypersensitivity and gut microbiota. Because both IBD and functional gastrointestinal disease (FGID) could share similar symptoms and some pathophysiology, it is sometimes challenging to distinguish them exactly. However, to reduce the risk of overtreatment or insufficient control of inflammation, exact diagnosis of functional disease or symptoms in quiescent IBD patients is important. Because there is limited randomized controlled trials or prospective study currently, most of the therapeutic approach in IBD patients are empirical or referred to those of functional gastrointestinal disorders. However, approaches based on pathophysiological mechanisms could give appropriate therapies for both IBD and FGIDs.

Gastroparesis Symptoms Associated with Intestinal Hypomotility: An Explorative Study Using Wireless Motility Capsule

Objective

Gastric emptying measurements are mandatory in gastroparesis diagnostics, but the association between delayed emptying and symptoms is questionable. It is imperative to find biomarkers better correlated to symptom generation. Hence, we examined the association between symptom severity and gastrointestinal motility measured by wireless motility capsule.

Patients and Methods

In this prospective single-centre study, patients with gastroparesis symptoms were simultaneously investigated with gastric emptying scintigraphy and wireless motility capsule, measuring regional transit times and contractility parameters. Symptom severity was assessed with the Patient Assessment of Upper Gastrointestinal Symptom Severity Index (PAGI-SYM), including the Gastroparesis Cardinal Symptom Index (GCSI).

Results

We included 107 patients (70% women). In the whole patient group, nausea correlated with the gastric (r_s = −0.31, p = 0.007), small bowel (r_s = −0.41, p < 0.001) and colonic (r_s = −0.33, p = 0.012) motility indices. In patients with idiopathic etiology, nausea correlated with small bowel motility index (r_s = −0.81, p < 0.001) and mean stomach pressure (r_s = −0.64, p = 0.013). We also found negative correlations between total GCSI score and maximum pressure of the small bowel (r_s = −0.77, p < 0.001) and colon (r_s = −0.74, p = 0.002). In diabetes patients, total PAGI-SYM score correlated with colonic motility index (r_s = −0.34, p = 0.012), and mean pressure of the colon correlated with upper abdominal pain (r_s = −0.37, p = 0.007). We found no association between symptoms, gastric emptying nor any other transit times.

Conclusion

In patients with gastroparesis symptoms, we found that symptom severity was associated with intestinal hypomotility. Based on these results, gastroparesis diagnostics should also include an evaluation of the small bowel and colon.

The Utility of Adding a Liquid-Nutrient Meal to Aid Interpretation of Small-Bowel Transit Scintigraphy

Small-bowel transit scintigraphy (SBTS) evaluates the accumulation of a radiolabeled meal in the terminal ileal reservoir (TIR) 6 h after ingestion. The location of the TIR may be difficult to determine because anatomic information is limited; for equivocal studies, the patient is asked to return the next day to help determine the TIR location by potential transit into the colon. The purpose of this study was to evaluate whether administration of an additional liquid-nutrient meal (LNM) at 6 h can promote movement of the radiolabeled meal to aid in the interpretation of SBTS and eliminate the need for the patient to return. Methods: This retrospective study reviewed 117 SBTS studies from February 2017 to September 2019. Patients were fed a standardized mixed radiolabeled solid-liquid meal for gastric emptying with SBTS according to Society of Nuclear Medicine and Molecular Imaging practice guidelines. An additional LNM was given at 6 h, and post-LNM images were obtained at least 20 min after the LNM. Two board-certified nuclear medicine physicians independently evaluated all images as equivocal or diagnostic at 6 h. Results: Of the 117 patients (71.8% female; median age, 42.0 y) undergoing SBTS, 37 were equivocal cases at 6 h before the LNM (31.6%; 95% CI, 23.3%-40.9%), compared with 12 equivocal cases after the LNM (10.3%; 95% CI, 5.4%-17.2%). Of the equivocal cases, 25 (69.4%; 95% CI, 51.9%-83.7%) had a definitive result after the LNM, whereas 11 (30.6%; 95% CI, 16.4%-48.1%) remained equivocal and 1 showed rapid transit. Among the 23 patients with gastroparesis, only 13 (57%) responded to the LNM, and none of the 3 patients with irritable bowel syndrome responded. Conclusion: The number of equivocal SBTS cases decreased after administration of an LNM at 6 h, converting to a definitive result. This suggests that with use of an LNM, most patients can complete SBTS in 1 d without the need for repeat imaging at 24 h. Administering an LNM appears to be less effective for patients with gastric disorders. However, the clinical significance remains to be explored, and it is unclear whether such patients have both a gastric and a small-bowel disorder, hence reducing any motility-promoting effect of the LNM.

Quantification of mucosal EEC in jejunum. A comparative study of IBS patients and healthy controls

Background: Enteroendocrine cells (EEC) have been suggested to have a role in the pathogenesis of irritable bowel syndrome (IBS). Although many studies have analysed possible numeric changes of EEC in IBS, the results differ between different studies. One reason might be due to difficulties in standardising the morphometric method.Aim: The aim of this study was to compare two different methods for counting EEC in jejunum biopsies from patients with IBS and healthy controls.Method: Fifty-one patients with IBS and 35 healthy controls were included in the study. Jejunum mucosa was procured using a Watson capsule. Slides were immunostained for serotonin and chromogranin A and then scanned digitally. The morphometry was done by counting cells per high power field (hpf) and per mm² after defining area of the mucosa. The two methods were compared using Bland Altman analysis.Results: There was no difference in the number of EEC in patients with IBS compared to healthy controls. The number of cells detected by per mm² area of mucosa were higher than number of cells per hpf. Counting EEC per high power field systematically underestimated the number of cells in the mucosal area.Conclusions: Counting cells per mm² mucosal area gives a better representation of the number of EEC in small bowel mucosa. The finding of no difference in EEC numbers does not imply an equal function and further studies are needed to evaluate the role, if any of EEC, in IBS.

Validation of Diagnostic and Performance Characteristics of the Wireless Motility Capsule in Patients With Suspected Gastroparesis

BACKGROUND & AIMS

It is a challenge to make a diagnosis of gastroparesis. There is good agreement in results from wireless motility capsule (WMC) analysis and gastric emptying scintigraphy (GES), but the diagnostic yield of WMC is unclear and the accuracy of this method has not been validated. We compared the performance characteristics of WMC vs GES in assessing gastric emptying in patients with suspected gastroparesis.

METHODS

We performed a prospective study of 167 subjects with gastroparesis (53 with diabetes and 114 without) at 10 centers, from 2013 through 2016. Subjects were assessed simultaneously by GES and with a WMC to measure gastric emptying and regional transit. Delayed gastric emptying by GES was defined as more than 10% meal retention at 4 hrs whereas delayed gastric emptying by WMC was defined as more than 5 hrs for passage of the capsule into the duodenum; a severe delay in gastric emptying was defined as a gastric emptying time of more than 12 hrs by WMC or more than 35% retention at 4 hrs by GES. Rapid gastric emptying was defined as less than 38% meal retention at 1 hr based on by GES or gastric emptying times less than 1:45 hrs by WMC. We compared diagnostic and performance characteristics of GES vs WMC.

RESULTS

Delayed gastric emptying was detected in a higher proportion of subjects by WMC (34.6%) than by GES (24.5%) (P=.009). Overall agreement in results between methods was 75.7% (kappa=0.42). In subjects without diabetes, the WMC detected a higher proportion of subjects with delayed gastric emptying (33.3%) than GES (17.1%) (P < .001). A higher proportion of subjects with diabetes had delayed gastric emptying detected by GES (41.7%) compared with non-diabetic subjects (17.1%) (P=.002). Severe delays in gastric emptying were observed in a higher proportion of subjects by WMC (13.8%) than by GES (6.9%) (P = .02). Rapid gastric emptying was detected in a higher proportion of subjects by GES (13.8%) than by WMC (3.3%) (P < .001). Regional and generalized transit abnormalities were observed in 61.8% subjects and only detected by WMC.

CONCLUSION

Although there is agreement in analysis of gastric emptying by GES vs WMC, WMC provides higher diagnostic yield than GES. WMC detects delayed gastric emptying more frequently than GES and identifies extra-gastric transit abnormalities. Diabetic vs non-diabetic subjects have different results from GES vs WMC. These findings could affect management of patients with suspected gastroparesis. ClinicalTrials.gov no: NCT02022826.

Banha-sasim-tang improves gastrointestinal function in loperamide-induced functional dyspepsia mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Banha-sasim-tang (BST; Hange-shashin-to in Kampo medicine; Banxia xiexin tang in traditional Chinese medicine) is a traditional Chinese harbal medicine that has been commonly used for gastrointestinal disorders.

AIM OF THE STUDY

To investigate the pharmacological effects of BST, a standardized herbal drug, on main symptoms of functional dyspepsia including delayed gastric emptying, and underlying mechanisms of action in mouse model.

METHODS AND MATERIALS

Balb/C mice were pretreated with BST (25, 50, 100 mg/kg, po) or mosapride (3 mg/kg, po) for 3 days, and then treated with loperamide (10 mg/kg, ip) after 19 h fasting. A solution of 0.05% phenol red (500 μL) or 5% charcoal diet (200 μL) was orally administered, followed by scarifying and assessment of gastric emptying or gastro-intestinal motility. C-kit (immunofluorescence), nNOS (western blot) and gastric contraction-related gene expression were examined in stomach tissue.

RESULTS

The loperamide injection substantially delayed gastric emptying, while the BST pretreatment significantly attenuated this peristaltic dysfunction, as evidenced by the quantity of stomach-retained phenol red (p < 0.05 or 0.01) and stomach weight (p < 0.05 or 0.01). The BST pretreatment significantly tempered the loperamide-induced inactivation of c-kit and nNOS (p < 0.05 or 0.01) as well as the contraction-related gene expression, such as the 5HT₄ receptor (5HT₄R), anoctamin-1 (ANO1), ryanodine receptor 3 (RYR3) and smooth muscle myosin light chain kinase (smMLCK). The BST pretreatment also significantly attenuated the alterations in gastro-intestinal motility (p < 0.01).

CONCLUSION

Our results are the first evidence of the prokinetic agent effects of Banha-sasim-tang in a loperamide-induced FD animal model. The underlying mechanisms of action may involve the modulation of peristalsis via activation of the interstitial cells of Cajal and the smooth muscle cells in the stomach.

Comparison between small bowel manometric patterns and full-thickness biopsy histopathology in severe intestinal dysmotility

BACKGROUND

Intestinal manometry is the current standard for direct evaluation of small bowel dysmotility. Patients with abnormal motility can either be diagnosed of pseudo-obstruction when there are radiological findings mimicking mechanical intestinal obstruction or of enteric dysmotility when these findings are absent. The aim of the present study was to prospectively compare small bowel manometric abnormalities with histopathological findings in intestinal full-thickness biopsies in patients with severe dysmotility disorders.

METHODS

We investigated 38 patients with intestinal manometry and a subsequent full-thickness intestinal biopsy. Manometric recordings were read by 4 investigators and a diagnostic consensus was obtained in 35 patients. Histopathological analysis, including specific immunohistochemical techniques of small bowel biopsies was performed and compared to manometric readings.

KEY RESULTS

Patients with abnormal intestinal manometry had abnormal histopathological findings in 73% of cases. However, manometric patterns did not match with the specific neuromuscular abnormalities. Among patients with a neuropathic manometry pattern and abnormal histopathology, only 23% had an enteric neuropathy, whereas 62% had neuromuscular inflammation, and 15% an enteric myopathy. On the other hand, patients with a myopathic manometry pattern all had abnormal histopathology, however, none of them with signs of enteric myopathy.

CONCLUSION & INFERENCES

Small bowel dysmotility detected by intestinal manometry is often associated with abnormal neuromuscular findings in full-thickness biopsies. However, there is no correlation between the specific manometric patterns and the histopathological findings.

An activating gucy2c mutation causes impaired contractility and fluid stagnation in the small bowel

OBJECTIVE

Familial GUCY2C diarrhoea syndrome (FGDS) is caused by an activating mutation in the GUCY2C gene encoding the receptor guanylate cyclase C in enterocytes. Activation leads to increased secretion of fluid into the intestinal lumen. Twenty percent of the patients have increased risk of Crohn's disease and intestinal obstruction (CD, 20%) and the condition resembles irritable bowel syndrome with diarrhoea. We aimed to describe fluid content, contractility, peristaltic activity and bowel wall thickness in the intestine in fasting FGDS patients, using ultrasound, with healthy volunteers serving as controls.

METHODS

Twenty-three patients with FGDS and 22 healthy controls (HC) were examined with a Logiq E9 scanner in a fasting state. Bowel wall thickness was measured and fluid-filled small bowel loops were counted using three-dimensional (3D) magnetic positioning navigation. The HC ingested 500 ml PEG solution, an electrolyte balanced, non-absorbable solution, in order to investigate the contractions of the small bowel.

RESULTS

The fasting 23 FGDS patients had significantly higher number of fluid-filled small bowel segments compared to 22 fasting HC, p < 0.001. A high number of non-occlusive contractions in the ileum was observed, which was significant when compared to HC after ingesting PEG solution, p < 0.016. An increase in intestinal wall thickness or other signs of CD were not observed.

CONCLUSIONS

FGDS is characterised by multiple, fluid-filled small bowel loops with incomplete contractions and fluid stagnation in fasting state. These findings may play a role in the increased risk of bowel obstruction as well as IBS-like symptoms observed in these patients.

Recent advances in the diagnosis of irritable bowel syndrome

The symptom-based diagnosis of irritable bowel syndrome (IBS) has not been established in everyday clinical practice, and the diagnosis of this disorder remains one of exclusion. It has been demonstrated that the densities of duodenal chromogranin A, rectal peptide YY and somatostatin cells are good biomarkers for the diagnosis of sporadic IBS, and low-grade mucosal inflammation is a promising biomarker for the diagnosis of postinfectious IBS. Genetic markers are not useful as biomarkers for IBS since the potential risk genes have yet to be validated, and the intestinal microbiota cannot be used because of the lack of an association between a specific bacterial species and IBS. Furthermore, gastrointestinal dysmotility and visceral hypersensitivity tests produce results that are too nonconsistent and noncharacteristic to be used in the diagnosis of IBS. A combination of symptom-based assessment, exclusion of overlapping gastrointestinal diseases and positive biomarkers appears to be the best way to diagnose IBS.

Irritable bowel syndrome: Is it "irritable brain" or "irritable bowel"?

Irritable bowel syndrome (IBS) has been recognized as one of the most common and best studied disorders among the group of functional gastrointestinal disorders. It is a functional bowel disorder in which abdominal pain or discomfort is associated with defecation or a change in bowel habit. In the Western world, IBS appears to affect up to 20% of the population at any given time but in Asian countries, the median value of IBS prevalence defined by various criteria ranges between 6.5% and 10.1%, and community prevalence of 4% is found in North India. Those attending gastroenterology clinics represent only the tip of the iceberg. The disorder substantially impairs the quality of life, and the overall health-care costs are high. IBS has therefore gained increased attention from clinicians, researchers, and pharmaceutical industries. It is often frustrating to both patients and physicians as the disease is usually chronic in nature and difficult to treat. However, the understanding of IBS has been changing from time to time and still most of its concepts are unknown. In this review we have discussed, debated, and synthesized the evidence base, focusing on underlying mechanisms in the brain and bowel. We conclude that it is both brain and bowel mechanisms that are responsible. The clinical implication of such mechanisms is discussed.

Multi-Dimensional Gastrointestinal Symptom Severity Index: Validation of a Brief GI Symptom Assessment Tool

Few instruments have been developed and validated for the evaluation of multi-dimensional GI symptoms. The Gastrointestinal Symptoms Severity Index (GISSI), a multi-dimensional, self-report instrument, was designed as a brief measure of the frequency, severity, and bothersomeness of individual GI and pelvic floor/urogynecologic symptoms.

AIM

To report the psychometric properties of the GISSI subscales, including factorial structure, validity, and internal consistency.

METHODS

The GISSI included 32 items that assessed upper and lower GI symptoms and seven items related to pelvic floor/urogynecologic symptoms. A total of 934 patients presenting for upper and lower GI complaints completed the questionnaire between January 2013 and December 2013. The sample was randomly split into derivation (n = 466) and validation datasets (n = 468). A non-patient sample of 200 was collected separately.

RESULTS

Exploratory factor analysis supported a six-factor model for the derivation sample that accounted for 69.3 % of the total variance. The six GI symptom clusters were labeled as constipation/difficult defecation (five items), abdominal pain/discomfort (four items), dyspepsia (four items), diarrhea/anal incontinence (four items), GERD/chest symptoms (four items), and nausea/vomiting (two items). Inclusion of additional items related to female pelvic floor/urogynecologic symptoms resulted in a separate factor. Confirmatory factor analysis of the validation dataset supported the a priori hypothesized six-factor measurement model (Χ (2)(428) = 1462.98; P < 0.001; GFI = .88; RMSEA = .051).

CONCLUSION

The GISSI demonstrated good to excellent psychometric properties and provided multi-dimensional scaling of prominent GI symptom clusters. Further validation may provide an efficient, valid, and reliable measure of patient-reported clinical outcomes.

Interaction between ingested nutrients and gut endocrine cells in patients with irritable bowel syndrome (review)

Several endocrine cell abnormalities have been reported in different segments of the gastrointestinal tract of patients with irritable bowel syndrome (IBS). These cells have specialized microvilli that project into the lumen; they function as sensors for the gut contents and respond to luminal stimuli (mostly ingested nutrients) by releasing hormones into the lamina propria, where they exert their effects via a paracrine/endocrine mode of action. Certain food items trigger the symptoms experienced by IBS patients, including those rich in fermentable oligo-, di- and monosaccharides, and polyols (FODMAPs). In this review, we present the argument that the effects of both FODMAPs and the proportional intake of proteins, fats and carbohydrates on IBS symptoms may be caused by an interaction with the gut endocrine cells. Since the gut hormones control and regulate gastrointestinal motility and sensation, this interaction may be responsible for abnormal gastrointestinal motility and the visceral hypersensitivity observed in these patients. There is no consistent evidence that IBS patients suffer from food allergy. The role of gluten intolerance in the development of IBS symptoms in these patients remains a matter of controversy. Individual guidance on food management, which includes restrictions in the intake of FODMAP-rich foods and testing diets with different proportions of proteins, fats and carbohydrates has been found to reduce the symptoms, improve the quality of life, and make the habitual diet of IBS patients more healthy.

A randomised, controlled study of small intestinal motility in patients treated with sacral nerve stimulation for irritable bowel syndrome

Background

Irritable bowel syndrome (IBS) is among the most common gastrointestinal disorders worldwide. In selected patients with severe diarrhoea-predominant or mixed IBS subtypes sacral nerve stimulation (SNS) alleviates IBS-specific symptoms and improves quality of life. The mode of action, however, remains unknown. The present study aimed to evaluate the effect of SNS on small intestinal motility in IBS patients.

Methods

Twenty patients treated with SNS for severe diarrhoea-predominant or mixed IBS were included in a randomised, controlled, crossover study. The neurostimulator was turned ON or OFF for the first one month and then to the opposite setting for the next month. Gastrointestinal transit patterns were investigated with the Motility Tracking System-1 (MTS-1) at the end of each the ON and OFF period. Primary endpoint was change in the velocity of the magnetic pill within the small intestine. Statistical testing was performed with Wilcoxon’s rank sum test and Fisher’s exact test.

Results

The median velocity of the magnetic pill through the small intestine in the fasting state was not significantly different between periods with and without SNS (Group ON-OFF: median change 0 m/h (range -1.07, 0.63), Group OFF-ON: median change 0.27 m/h (range -0.59, 1.12)) (p = 0.25). Neither, was the median velocity of the magnetic pill through the small intestine in the postprandial state significantly different between periods with and without SNS (Group ON-OFF: median change -0.13 m/h (range -0.46, 0.23), Group OFF-ON: median change 0.015 m/h (range -0.48, 0.59)) (p = 0.14).

Conclusion

Even though SNS may reduce symptoms of diarrhoea-predominant and mixed IBS, it has no detectable effect on small intestinal transit patterns.

Trial registration

Clinical.trials.gov, (NCT00919672).

Autonomic nervous system activity in constipation-predominant irritable bowel syndrome patients

Background

The main mechanism underlying irritable bowel syndrome is currently believed to be a dysfunction of the brain-gut axis. Autonomic nervous system dysfunction can contribute to development of irritable bowel syndrome symptoms by disturbing visceral sensations.

Material/Methods

Thirty patients with a diagnosis of constipation-predominant irritable bowel syndrome and 30 healthy volunteers were included in the study. Resting and functional autonomic nervous system tests and percutaneous electrogastrography were performed. Plasma adrenalin, noradrenalin, insulin, ghrelin and cholecystokinin activity was analyzed.

Results

Increased sympathetic activation with disturbed parasympathetic function was demonstrated. Patients had substantially higher plasma catecholamine concentration, which confirms sympathetic overbalance. Hyperinsulinemia may explain sympathetic predominance followed by gastric and intestinal motility deceleration. Abnormal, reduced ghrelin and cholecystokinin titre may disturb brain-gut axis functioning and may be responsible for gastric motility deceleration. In electrogastrography, distinctly lower values of fasting normogastria percentage and dominant power were observed. Patients had substantially lower slow wave coupling percentage both in fasting and postprandial periods, which negatively correlated with plasma catecholamines level. Gastric myoelectrical activity disturbances may result from lack of sympatho-parasympathetic equilibrium.

Conclusions

Central sympathetic influence within the brain-gut axis is most probably responsible for myoelectrical activity disturbances in irritable bowel syndrome patients.

Irritable bowel syndrome: Diagnosis and pathogenesis

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome III criteria. A combination of the Rome III criteria, a physical examination, blood tests, gastroscopy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS: heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following: genetic factors, dietary intake, intestinal flora, or low-grade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI- and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.

Low densities of serotonin and peptide YY cells in the colon of patients with irritable bowel syndrome

BACKGROUND

The gut hormones are important in regulating gastrointestinal motility. Disturbances in gastrointestinal motility have been reported in patients with irritable bowel syndrome (IBS). Reduced endocrine cell density, as revealed by chromogranin A, has been reported in the colon of IBS patients.

AIMS

To investigate a possible abnormality in the colonic endocrine cells of IBS patients.

METHODS

A total of 41 patients with IBS according to Rome Criteria III and 20 controls were included in the study. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. The biopsies were immunostained for serotonin, peptide YY (PYY), pancreatic polypeptide (PP), entroglucagon, and somatostatin cells. Cell densities were quantified by computerized image analysis.

RESULTS

Serotonin and PYY cell densities were reduced in the colon of IBS patients. PP, entroglucagon, and somatostatin-immunoreactive cells were too few to enable reliable quantification.

CONCLUSION

The cause of these observations could be primary genetic defect(s), secondary to altered serotonin and/or PYY signaling systems and/or subclinical inflammation. Serotonin activates the submucosal sensory branch of the enteric nervous system and controls gastrointestinal motility and chloride secretion via interneurons and motor neurons. PYY stimulates absorption of water and electrolytes, and inhibits prostaglandin (PG) E2, and vasoactive intestinal peptide, which stimulates intestinal fluid secretion and is a major regulator of the "ileal brake". Although the cause and effect relationship of these findings is difficult to elucidate, the abnormalities reported here might contribute to the symptoms associated with IBS.

Comparative analysis of phase III migrating motor complexes in stomach and small bowel using wireless motility capsule and antroduodenal manometry

BACKGROUND

  Assessment of phase III MMC is often not performed due to the invasive nature of antroduodenal manometry used to detect it. The aim of the study was to evaluate the ability of wireless motility capsule (WMC) to detect phase III MMC and correlate it with the simultaneous measurements by antroduodenal manometry (ADM).

METHODS

  Eighteen patients underwent simultaneous ADM and WMC. MMCs were identified first on ADM and then correlated with WMC events occurring simultaneously. Frequency of contractions per min, AUC, MI, and criteria for amplitude thresholds of contractions representing MCCs on WMC tracings were defined.

KEY RESULTS

  In 18 patients, a total of 29 MMCs were recorded by ADM. WMC detected 86% of MMC events measured by ADM. Hundred percent (10/10) of MMCs in stomach were detected by WMC, whereas 79% (15/19) of MMCs were detected in SB. The sensitivity and specificity of WMC high amplitude contractions to represent phase III MMC were 90% and 71.8% in the stomach; 73.7% and 84.7% in SB, respectively, and negative predictive value was 99.9% in both regions.

CONCLUSIONS & INFERENCES

  Wireless motility capsule was able to detect the phase III MMCs as the high amplitude contractions with good fidelity. WMC does not detect the propagation of MMC. Using the pressure thresholds, WMC can detect high amplitude contraction representing phase III MMC with favorable sensitivity/specificity profile and 99.9% negative predictive value. This observation may have clinical significance, as the absence of high amplitude contractions recorded by WMC during fasting state suggests absence of MMCs.

Traditional thoughts on the pathophysiology of irritable bowel syndrome

The pathogenesis of symptoms in irritable bowel syndrome (IBS) is multifactorial and varies from patient to patient. Disturbances of motor function in the small intestine and colon and smooth-muscle dysfunction in other gut and extraintestinal regions are prominent. Abnormalities of sensory function in visceral and somatic structures are detected in most patients with IBS, which may relate to peripheral sensitization or altered central nervous system processing of afferent information. Contributions from psychosocial disturbances are observed in patients from tertiary centers and primary practice. Proof of causation of symptom genesis for most of these factors is limited.

Abnormal small-intestinal endocrine cells in patients with irritable bowel syndrome

BACKGROUND

General disturbances in gastrointestinal motility have been reported in patients with irritable bowel syndrome (IBS). The gastrointestinal tract hormones play an important role in regulating gastrointestinal motility.

AIMS

To investigate a possible abnormality in the small intestinal endocrine cells of IBS patients.

METHODS

Included in the study were 41 patients with irritable bowel syndrome according to Rome Criteria III and 42 healthy controls. Duodenal biopsies were obtained from both patients and controls during gastroscopy. The biopsies were immunostained by avidin-biotin-complex method for secretin, CCK, GIP, somatostatin, and serotonin cells. The cell densities were quantified by computerized image analysis.

RESULTS

The density of secretin- and CCK-immunoreactive cells in patients with IBS was significantly reduced. The reduction in secretin and CCK cells occurred only in IBS-diarrhea patients, but not in IBS-constipation subtype. Both GIP and somatostatin cell densities were reduced in the duodenum of IBS patients. There was no statistical difference between the subtypes of IBS patients, regarding secretin, CCK, GIP, or somatostatin cell densities. Serotonin cell density was not affected in patients with IBS.

CONCLUSIONS

The low densities of secretin and CCK cells in IBS-diarrhea patients may cause a functional pancreatic insufficiency as well as inadequate gall emptying, as these hormones stimulate pancreatic bicarbonate and enzyme secretion and CCK stimulates as well gall bladder contraction. Low densities of secretin, GIP, and somatostatin cells in IBS patients might result in a high secretion of gastric acid, as secretin, GIP, and somatostatin inhibit gastric acid secretion.

Asian motility studies in irritable bowel syndrome

Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS.

Peripheral factors in the pathophysiology of irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors are thought to contribute to the symptoms of IBS, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity. In this review the involvement of peripheral factors in the pathophysiology in IBS is reviewed. Altered GI motility is commonly found in this patient group, even though a specific motor pattern has been hard to find. Colonic transit has been found to be of relevance for the bowel habit of the patient. Abnormal gas handling within the gut is also commonly seen, and seems to be one, but not the only factor responsive for bloating. There is also limited evidence supporting the presence of abnormal GI secretion in IBS, but its relevance for symptoms remains unclear. Visceral hypersensitivity is currently considered to be one of the most important pathophysiological factors in IBS. It can be modulated by several external and internal factors and recent studies support an association between colorectal sensitivity and the symptoms reported by the patients, especially pain.

Intestinal and anorectal motility and functional disorders

Motility and functional disorders of the small intestine, the colon and the anorectum can induce or contribute to symptoms such as diarrhoea, constipation and abdominal pain and may impair nutrient absorption in severe cases. Acute affections of intestinal functions e.g. during gastrointestinal infections usually need no functional diagnostics but resolve spontaneously or with adequate therapy of the underlying disease. By contrast, chronic disturbances of small intestinal, colonic and anorectal motility and/or sensitivity are subject to gastrointestinal function tests. The role of these tests for diagnosis and therapeutic handling of severe intestinal dysmotility/chronic intestinal pseudo-obstruction, severe constipation, diarrhoea, fecal incontinence and irritable bowel syndrome will be discussed in this review that mainly focuses on adults.

The functional-organic dichotomy: postinfectious irritable bowel syndrome and inflammatory bowel disease-irritable bowel syndrome

Gastroenterologists often encounter situations when the clinical and pathophysiological features that typically distinguish functional from organic disorders overlap. This "blurring of boundaries" can occur with post-infectious irritable bowel syndrome (PI-IBS), a subset of IBS and a newly described entity IBD-IBS. The key associating features include pain and usually diarrheal symptoms that are disproportionate to the observed pathology, microscopic inflammation, and often a co-association with psychological distress. A previous initiating gastrointestinal infection is required for PI-IBS and assumed for IBD-IBS. Using this perspective we discuss the clinical and pathophysiological features of PI-IBS and IBD-IBS and the growing evidence for the overlapping features of these two disorders in terms of alteration of gut flora, immune dysregulation, and role of stress. A unifying model of PI-IBS and IBD-IBS is proposed that may have important clinical and research implications. It obligates us to reframe our understanding of illness and disease from the dualistic biomedical model into a more integrated biopsychosocial (BPS) perspective.

The clinical overlap between functional dyspepsia and irritable bowel syndrome based on Rome III criteria

BACKGROUND

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). To date, no surveys have been performed to investigate the clinical overlap between these two disorders using Rome III criteria. Our aim was to investigate the prevalence and risk factors for the overlap of FD and IBS based on Rome III criteria in a large clinical sample.

METHODS

Consecutive patients at the general gastroenterology outpatient clinic were requested to complete a self-report questionnaire. FD and IBS were defined by Rome III criteria.

RESULTS

Questionnaires were returned by 3014 patients (52.8% female, 89% response rate). FD-IBS overlap was observed in 5.0% of the patients, while 15.2% and 10.9% of the patients were classified as FD alone and IBS alone, respectively. Compared with non-IBS patients, the odds ratio of having FD among IBS patients was 2.09 (95% CI: 1.68-2.59). Patients with FD-IBS overlap had higher severity scores for the postprandial fullness symptom (2.35 +/- 1.49 vs. 1.72 +/- 1.59, P < 0.001) and overall FD symptom (6.65 +/- 2.88 vs. 5.82 +/- 2.76, P = 0.002) than those with FD alone. The only independent risk factor for FD-IBS overlap vs. FD alone was the presence of postprandial fullness symptom (OR 2.67, 95% CI: 1.34-5.31).

CONCLUSION

Clinical overlap of FD and IBS according to Rome III criteria is very common. One risk factor for FD-IBS overlap is the presence of postprandial fullness symptom. This study provides clues for future pathophysiological studies of FD and IBS.

The clinical overlap between functional dyspepsia and irritable bowel syndrome based on Rome III criteria

Background

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). To date, no surveys have been performed to investigate the clinical overlap between these two disorders using Rome III criteria. Our aim was to investigate the prevalence and risk factors for the overlap of FD and IBS based on Rome III criteria in a large clinical sample.

Methods

Consecutive patients at the general gastroenterology outpatient clinic were requested to complete a self-report questionnaire. FD and IBS were defined by Rome III criteria.

Results

Questionnaires were returned by 3014 patients (52.8% female, 89% response rate). FD-IBS overlap was observed in 5.0% of the patients, while 15.2% and 10.9% of the patients were classified as FD alone and IBS alone, respectively. Compared with non-IBS patients, the odds ratio of having FD among IBS patients was 2.09 (95% CI: 1.68–2.59). Patients with FD-IBS overlap had higher severity scores for the postprandial fullness symptom (2.35 ± 1.49 vs. 1.72 ± 1.59, P < 0.001) and overall FD symptom (6.65 ± 2.88 vs. 5.82 ± 2.76, P = 0.002) than those with FD alone. The only independent risk factor for FD-IBS overlap vs. FD alone was the presence of postprandial fullness symptom (OR 2.67, 95% CI: 1.34–5.31).

Conclusion

Clinical overlap of FD and IBS according to Rome III criteria is very common. One risk factor for FD-IBS overlap is the presence of postprandial fullness symptom. This study provides clues for future pathophysiological studies of FD and IBS.

The nocturnal jejunal migrating motor complex: defining normal ranges by study of 51 healthy adult volunteers and meta-analysis

Interdigestive human small bowel motility is characterized by the migrating motor complex (MMC). The aims of this study were to: (i) establish the normal range of variables of the nocturnal jejunal MMC and (ii) incorporate these data in a subsequent meta-analysis. Eighty-one recordings were performed by prolonged (24 h) ambulatory manometry in 51 subjects in two centres. Quantitative analysis was undertaken of 419 Phase III and 332 Phase II episodes. Adjusted mean values of seven variables were calculated using a mixed-effects model. Meta-analysis of pooled published data to generate a reliable 95% reference range was also performed. Adjusted mean values and confidence intervals are presented for all seven variables. Intrasubject variances were large in comparison with intersubject. Meta-analysis of 19 studies (356 pooled patients) meeting inclusion criteria produced wide reference ranges. At least five such ranges are useful for the detection of abnormality in the individual. This is the largest study of normal volunteers presented to date, with ranges for many variables produced using appropriate statistical methodology. A model for definition of abnormality has been proposed. We recommend that these data may be used by investigators in this field as a complement to other existing indicators of small bowel dysmotility.

Functional findings in irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Several studies have demonstrated altered GI motor function in IBS patients and the pattern differs between IBS subgroups based on the predominant bowel pattern. Few studies have so far addressed GI secretion in IBS, but there are some evidence supporting altered secretion in the small intestine of IBS patients. Visceral hypersensitivity is currently considered to be perhaps the most important pathophysiological factor in IBS. Importantly, several external and internal factors can modulate visceral sensitivity, as well as GI motility, and enhanced responsiveness within the GI tract to for instance stress and nutrients has been demonstrated in IBS patients. Today IBS is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral alterations probably dominating in some patients and disturbed central processing of signals from the periphery in others.

Functional dyspepsia and irritable bowel syndrome, are they different entities and does it matter

A high prevalence of overlap between functional dyspepsia and irritable bowel syndrome has been consistently and universally reported. Recent studies demonstrating shared common pathophysiological disturbances including delayed gastric emptying and visceral hypersensitivity involving more than one region, suggest that these patients have a generalised rather than regional, disorder of the gut. Furthermore, a study of the natural history of dyspepsia suggests that with time, a substantial proportion will evolve into IBS. The recognition of IBS in dyspeptic patients has potentially profound therapeutic importance. It could help to reduce the risk of unnecessary cholecystectomy in IBS patients. The ability to appreciate the extent of involvement could allow us to address the disturbances more comprehensively, and thereby achieve greater patient satisfaction with their treatment.

Rectal distension modulates canine gastric tone and accommodation

Rectal distension affects upper GI myoelectrical activity and motility. The aim of this experiment was to investigate the effect of rectal distension on gastric tone, accommodation, and the underlying mechanism. Seven healthy dogs were surgically prepared and studied. Gastric tone and accommodation were assessed with a barostat. In Experiment 1, the effect of rectal distension on gastric tone and accommodation was evaluated; in Experiment 2, rectal distensions with various volumes were randomly applied and its effects on gastric tone were evaluated; and in Experiment 3, the role of the cholinergic pathway in distension-induced gastric relaxation was assessed. The results showed the following. (1) Rectal distension exerted an inhibitory effect on gastric tone, and this response was distension volume-dependent. (2) Postprandial gastric volume was similar in the control (468.6 +/- 24.7 ml) and the distension study (463.2 +/- 17.5 ml). However, rectal distension increased the preprandial gastric volume, and subsequently decreased the extent of gastric accommodation (139.3 +/- 34.7 ml), which was significantly lower than that of the control (383.2 +/- 26.3 ml; P < 0.001). (3) An intravenous bolus of atropine increased the astric volume from the baseline of 89.4 +/- 12.6 ml to 161.5 +/- 9.8 ml (P < 0.01), and subsequent rectal distension further increased this volume, but the overall change was comparable between the control (297.6 +/- 18.7 ml) and the atropine study (312.1 +/- 21.9 ml; P > 0.05). In conclusion, rectal distension inhibits gastric tone in a volume-dependent manner and impairs gastric accommodation. Atropine dose not block the effect of rectal distension on proximal gastric tone, suggesting that the observed effect may not be mediated by cholinergic pathway.

Review article: gastric emptying in functional gastrointestinal disorders

Although delayed gastric emptying has been described in several functional gastrointestinal disorders, and appears to be especially common in functional dyspepsia, the relationship of this finding to symptoms and basic pathophysiology is difficult to define. The delineation of the interactions between delayed gastric emptying, on the one hand, and symptom pathogenesis, on the other, has been hampered by several factors. These include the limitations of the methodology itself, the extent of overlap between the various functional disorders and the sensitivity of gastric emptying to factors external to the stomach, be they elsewhere within the gastrointestinal tract, in the central nervous system or in the environment. In many instances, delayed gastric emptying is an epiphenomenon, reflecting the overlap between inadequately defined functional syndromes, shared pathophysiology or the activation of physiological interactions between the various organs of the gut. In others, it may imply a truly diffuse motor disorder. The disappointments attendant on attempts to alleviate symptoms through approaches designed to accelerate gastric emptying should therefore not come as a surprise. Pending the definition of the true significance of delayed gastric emptying in all functional gastrointestinal disorders, caution should be exerted in the interpretation of this finding in a patient with functional symptoms.

Intestinal microecology and quality of life in irritable bowel syndrome patients

AIM: It has been noticed that gastroenteritis or dysentery plays a role in pathogenesis of irritable bowel syndrome (IBS), and antibiotics can increase functional abdominal symptoms, both of which may be partly due to intestinal flora disorders. This study was to determine the change of gut flora of IBS, a cluster of abdominal symptoms. Because of the chronic course and frequent occurrence of the disease, IBS patients suffered much from it. So the quality of life (Qol) of IBS patients was also evaluated in this study.

METHODS: Twenty-five Rome II criteria-positive IBS patients were recruited, and 25 age and gender-matched healthy volunteers were accepted as control. The fecal flora, including Lactobacillus, Bifidobacterium, Bacteroides , C. perfringens Enterobacteriacea and Enterococus, were analyzed quantitatively and qualitatively. We also calculated the ratio of Bifidobacterium to Enterobacteriaceae (B/E ratio) in both IBS patients and controls. In both groups, the data were further analyzed based on age difference, and comparisons were made between the younger and elder subgroups. We also evaluated the quality of life (QoL) of IBS patients and the control group using the Chinese version of SF-36 health questionnaire.

RESULTS: In IBS patients, the number of fecal Bifidobacterium was significantly decreased and that of Enterobacteriaceae was significantly increased compared with that in healthy controls (both P < 0.05).The mean microbial colonization resistance (CR) of the bowel in IBS patients was smaller than 1, making a significant difference compared with that in control which was more than 1 (P < 0.01). There was no significant difference in gut flora between two subgroups. While in control, the elder subgroup presented more Enterobacteriacea than the younger one (P < 0.05). Compared with the control group, IBS patients had significantly lower scores on all SF-36 scales, with the exception of physical functioning. However, there was no significant correlation between quality of life and enteric symptoms in IBS patients.

CONCLUSION: There are intestinal flora disorders in IBS patients, which may be involved in triggering the IBS-like symptoms. IBS patients experience significant impairment in QoL, however, the impairment is not caused directly by enteric symptoms.

Impact of coexisting irritable bowel syndrome on symptoms and pathophysiological mechanisms in functional dyspepsia

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS).

AIM

The aim of the present study was to investigate whether coexisting IBS is also associated with symptom pattern or pathophysiology in FD.

METHODS

In 309 consecutive FD patients (207 women, age 42 +/- 0.8 yr), questionnaires were used to assess the dyspepsia symptom pattern and the Rome II criteria for IBS. The overall symptom severity was calculated adding the severity score (0-3, 0 = absent, 3 = severe) of eight dyspepsia symptoms. All patients underwent Helicobacter pylori testing, gastric barostat to determine sensitivity to distention and accommodation to a meal, and gastric emptying breath test.

RESULTS

Fifty-four percent of the patients had FD alone, whereas 46% had FD + IBS. FD + IBS patients were more likely to be female (75%vs 60%, p < 0.01) and to have a greater weight loss (5.4 +/- 0.6 vs 3.5 +/- 0.4 kg, p < 0.05). Coexisting IBS did not increase the risk of having any of the dyspeptic symptoms but the overall symptom severity was significantly higher in FD + IBS (12.4 +/- 0.4 vs 9.8 +/- 0.3, p < 0.01). FD + IBS patients had a lower threshold for first perception (2.9 +/- 0.3 vs 3.8 +/- 0.3 mmHg, p < 0.05) and for discomfort (7.9 +/- 0.4 vs 9.5 +/- 0.5 mmHg, p < 0.05) and a greater prevalence of hypersensitivity to gastric distention (44%vs 28%, p < 0.05). Gastric emptying, accommodation to a meal, and prevalence of H. pylori infection did not differ in the two groups.

CONCLUSION

About half of the FD patients fulfill the Rome II criteria for IBS. FD + IBS is more prevalent in female patients and is associated with a higher weight loss, with greater overall symptom severity, and with hypersensitivity to distention.

Overlapping upper and lower gastrointestinal symptoms in irritable bowel syndrome patients with constipation or diarrhea

OBJECTIVES

Distinguishing between irritable bowel syndrome (IBS) and functional dyspepsia can be challenging because of the variations in symptom patterns, which commonly overlap. However, the overlap is poorly quantified, and it is equally uncertain whether symptom patterns differ in subgroups of IBS arbitrarily defined by primary bowel patterns of constipation (IBS-C) and diarrhea (IBS-D). We aimed to determine and to compare the distribution of GI symptoms, both, upper and lower, among IBS-C and IBS-D patients.

METHODS

A total of 121 consecutive patients presenting with a diagnosis of IBS were grouped according to primary bowel symptoms as IBS-C (58 women and 18 men, mean age 47 +/- 17 yr) or IBS-D (26 women and 19 men, mean age 47 +/- 15 yr). The Hopkins Bowel Symptom Questionnaire, which includes a brief Quality of Life assessment, and the Hopkins Symptom Checklist 90-Revised were completed by all patients at intake.

RESULTS

IBS-C patients reported significantly more overall GI symptoms when compared to patients with IBS-D (6.67 vs 4.62, respectively, p<0.001). Abdominal pain patterns differed in patients with IBS-C versus IBS-D (lower abdominal pain: 40.8% vs 24.4% p=0.05 and upper abdominal pain: 36.8% vs 24.4%, respectively). Bloating was substantially more common in IBS-C patients (75%) than in IBS-D (40.9%). There were no significant differences in personality subscales by IBS subgroup; however, somatization was positively associated with multiple symptom reports and was negatively correlated with quality of life.

CONCLUSIONS

Upper GI symptoms consistent with functional dyspepsia were more frequent in IBS-C. Although there was considerable overlap of upper and lower GI symptoms in patients with IBS-C and IBS-D, the former had more frequent lower abdominal pain and bloating.

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Full-thickness biopsy of the jejunum reveals inflammation and enteric neuropathy in irritable bowel syndrome

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is regarded as a functional bowel disorder. Few studies have looked for histopathologic changes in the gut and only then in biopsy specimens from intestinal mucosa. Because bowel function is governed mainly by nerve plexuses in the bowel wall, we have investigated full-thickness bowel biopsy specimens in patients with severe IBS.

METHODS

We used a laparoscopy-assisted technique to obtain full-thickness biopsy specimens from the proximal jejunum. Tissue specimens were investigated with light microscopy using routine stainings and immunohistochemical techniques. Horizontal sectioning was done to visualize large areas of the myenteric plexus. Fifteen autopsy specimens were used as controls regarding the myenteric plexus. Colorectal adenoma controls with terminal ileum biopsy specimens and full-thickness jejunal biopsy specimens from patients with degenerative enteric neuropathy were used as control groups for intraepithelial lymphocyte counts.

RESULTS

Ten patients (2 males, 8 females) were studied. In 9 patients, we found low-grade infiltration of lymphocytes in the myenteric plexus. Lymphocytes had peri- and intraganglionic location. The mean number of lymphocytes per ganglion ranged from 1.9 to 7.1 per patient, with an overall mean of 3.4. No intraganglionic lymphocytes were found in the control group and only a few periganglionic lymphocytes (mean, 0.2). Four patients had concomitant intraepithelial lymphocytosis. Neuron degeneration was evident in 6 of 9 patients with and 1 patient without ganglionic lymphocyte infiltration.

CONCLUSIONS

Our findings indicate that inflammation and neuronal degeneration in the myenteric plexus are involved in the pathogenesis of IBS.

Dyspeptic symptoms and gastric emptying in the irritable bowel syndrome

OBJECTIVES

Irritable bowel syndrome (IBS) and dyspepsia often overlap. Delayed gastric emptying has been reported in IBS patients, although conflicting results exist. Whether overlapping dyspepsia correlates with gastric emptying abnormalities in IBS patients has not been clarified. This study aimed to evaluate gastric emptying of solids and its relationship with dyspeptic symptoms in IBS patients.

METHODS

A total of 146 IBS outpatients seen in a referral center were evaluated for dyspeptic symptoms using a validated questionnaire. Gastric emptying of solids was evaluated scintigraphically in all patients and in 50 healthy controls.

RESULTS

Overlapping dyspepsia was diagnosed in 96 (66%) IBS patients. On average, gastric emptying rates were lower in IBS patients (mean +/- SEM, 33% +/- 1%/h) compared with controls (40% +/- 2%/h; p < 0.01). Specifically, gastric emptying was delayed in IBS patients with overlapping dyspepsia (31% +/- 1%/h; p < 0.01), whereas IBS patients without dyspeptic complaints showed gastric emptying rates (37% +/- 2%/h) that were similar to those of healthy controls (40% +/- 2%/h). Relevant postprandial fullness (OR = 4.7, 95% CI = 1.8-12.5) and relevant nausea (OR = 3.3, 95% CI 1.2-9.3) were independently associated with delayed gastric emptying.

CONCLUSIONS

IBS patients without overlapping dyspepsia have normal gastric emptying of solids. A significant association exists in IBS patients between delayed gastric emptying and overlapping relevant postprandial fullness and nausea.

Consultations and referrals for dyspepsia in general practice--a one year database survey

OBJECTIVE

Dyspepsia usually presents first in primary care. There are many reasons for referral including urgent problems (for example, haematemesis and melaena), treatment failure, or to exclude serious pathology. Referral will change the population characteristics of primary and secondary care dyspeptics. Many of the guidelines for primary care dyspepsia, however, are based on secondary care research on these referred patients. The aim of this study was to describe the prevalence of dyspepsia in general practice, the characteristics of patients presenting with dyspepsia in primary care, and the clinical and non-clinical determinants of referral in these patients.

DESIGN

Cross sectional survey of the consultation records of patients presenting with dyspepsia in primary care during a one year period.

METHODS

Dyspeptic patients who consulted their general practitioner (GP) in 1997 were selected on the basis of International Classification of Primary Care codes using a computer search among 20 sentinel practices affiliated with the Utrecht Network of General Practitioners. Cross tables and logistic regression analysis were carried out to reveal patient characteristics and determinants of referral.

RESULTS

The prevalence of dyspepsia presenting in primary care in 1997 was 3.4% (1740/48958). These patients were usually not referred during the first consultation. Men, elderly patients, and patients with a previous history of dyspepsia were referred to secondary care more frequently than other dyspeptic patients. Patients diagnosed with both irritable bowel syndrome and dyspepsia were at risk of being referred most.

CONCLUSION

Dyspepsia is a frequently occurring complaint in primary care and patients are usually treated by their GP. Besides clinically relevant reasons for referral, dyspeptic patients with irritable bowel syndrome seem to be more "at risk" of being referred to secondary care than other dyspeptic patients. The differences between primary and secondary care dyspeptic patients should be taken into account when interpreting research for guideline purposes. Further research is needed to clarify the background of the relation between irritable bowel syndrome and dyspepsia and its influence on referral.

Irritable bowel syndrome: causes and treatment

Irritable bowel syndrome (IBS) is a common health care problem worldwide. In the United States and Northern European countries, more women than men seek health care services for IBS. Nurses are often called on to help women with IBS manage their symptoms. This article reviews the literature related to gender differences in diagnosis, symptoms (gastrointestinal, somatic, and disturbed sleep), and physiologic and psychological factors as well as current pharmacologic therapies used in the management of IBS.

The association between Helicobacter pylori infection and functional dyspepsia in patients with irritable bowel syndrome

OBJECTIVE

Irritable bowel syndrome (IBS) is associated with an exaggerated response to a variety of physiological and nonphysiological gastrointestinal stimuli. Many patients with IBS also have functional dyspepsia. Our aim was to examine the hypothesis that Helicobacter pylori (H. pylori) infection may predispose IBS patients to functional dyspepsia.

METHODS

In 69 IBS patients, dyspeptic symptoms, H. pylori status, and sociodemographic and psychological variables (perceived stress, trait anxiety, and depression) were assessed. Sociodemographic and psychological variables were also evaluated in 52 control subjects.

RESULTS

Mean scores for perceived stress (17.1 +/- 6.0 vs 14.9 +/- 6.0, p = 0.05), trait anxiety (45.6 +/- 9.1 vs 41.1 +/- 7.8, p = 0.004) and depression (9.9 +/- 8.4 vs 5.0 +/- 5.5, p = 0.0002) were higher in IBS patients than in controls. In all, 33 of the 69 patients (47.8%) had H. pylori infection, and this was associated with relevant symptoms of epigastric pain (odds ratio [OR] = 6.77, 95% confidence interval [CI] 1.89-24.3) and postprandial upper abdominal fullness (OR = 4.23, 95% CI 1.38-13.2). H. pylori infection and female gender were independent predictors of the presence of relevant dyspepsia (OR = 8.31, 95% CI 2.35-29.5 and 6.06, 95% CI 1.71-21.5, respectively). Symptom intensity was associated with the level of perceived stress (total relevant symptom number > or =3 vs <3, OR = 1.16 per point on a 40-point perceived stress scale, 95% CI 1.01-1.34).

CONCLUSIONS

In IBS patients, the presence of dyspepsia is associated with H. pylori infection, female gender, and perceived stress.

Insulin restores neuronal nitric oxide synthase expression and function that is lost in diabetic gastropathy

Gastrointestinal dysfunction is common in diabetic patients. In genetic (nonobese diabetic) and toxin-elicited (streptozotocin) models of diabetes in mice, we demonstrate defects in gastric emptying and nonadrenergic, noncholinergic relaxation of pyloric muscle, which resemble defects in mice harboring a deletion of the neuronal nitric oxide synthase gene (nNOS). The diabetic mice manifest pronounced reduction in pyloric nNOS protein and mRNA. The decline of nNOS in diabetic mice does not result from loss of myenteric neurons. nNOS expression and pyloric function are restored to normal levels by insulin treatment. Thus diabetic gastropathy in mice reflects an insulin-sensitive reversible loss of nNOS. In diabetic animals, delayed gastric emptying can be reversed with a phosphodiesterase inhibitor, sildenafil. These findings have implications for novel therapeutic approaches and may clarify the etiology of diabetic gastropathy.

Twenty-four hour ambulatory antroduodenal manometry in normal subjects (co-operative study)

Circadian antroduodenal motor activity was studied in 40 normal subjects by means of a portable recording system consisting of a computerized data logger and a probe with microtransducers. The quantitative and qualitative characteristics of contraction events during the interdigestive and digestive periods, as well as during the awake and asleep periods, were analysed. The composition and timing of meals and night recumbence were standardized. In spite of the high interindividual variability in motor parameters, significant differences in the characteristics of interdigestive and digestive periods between waking and sleep states were found. This paper confirms the existence of a circadian variation in antroduodenal motor activity and provides reference values from a large series of normal subjects that can be used for statistical comparisons with those obtained from patients recorded with the same method.

Symptom differences in moderate to severe IBS patients based on predominant bowel habit

OBJECTIVE

We sought to determine if irritable bowel syndrome (IBS) patients with different bowel habit predominance differ in self-reported viscerosensory symptoms related to the upper and lower gastrointestinal (GI) tract, somatosensory symptoms, and constitutional functions.

METHODS

Six hundred and twenty-five Rome criteria-positive IBS patients completed a bowel symptom questionnaire (BSQ), psychological symptom checklist (SCL-90), and health status (SF-36). Bowel habit predominance for IBS patients was determined using the Rome criteria for functional constipation (IBS-C; n = 140) and functional diarrhea (IBS-D; n = 216). The BSQ included questions about viscerosensory symptoms of the upper (chest pressure, bloating, fullness, early satiety, nausea) and lower GI tract (bloating, pain, incomplete evacuation), somatosensory symptoms related to the musculoskeletal system (pain in neck/shoulders, lower back/hip, muscles/joints), and constitutional functions (sleep, appetite, libido). Analysis was further conducted between the IBS-C and IBS-D patients, controlling for gender and quality of sleep, and using the Bonferroni correction to control for multiple comparisons.

RESULTS

Female gender was more prevalent among IBS-C than IBS-D (77% vs 56.1%, p < 0.01), whereas age did not differ (40.2 +/- 1.2 yr vs 39.5 +/- 1.0 yr). Symptoms referred to the upper GI were more prevalent in IBS-C than IBS-D: early satiety (56.7% vs 33.9%, p < 0.004), fullness (63.2% vs 38.5%, p < 0.05), and a trend for upper bloating (80.3 vs 62.6%). IBS-C patients reported higher severity ratings for lower GI bloating (p < 0.001). IBS-C more commonly reported musculoskeletal symptoms (92.2% vs 75.4%, p < 0.001), as well as impairment in sleep (31.3 vs 17.5%, p < 0.009), appetite (35.0% vs 18.4%, p < 0.015) and sexual function (45.2% vs 33.1%, p < 0.0021). There were no differences in SCL-90 and SF-36 scores.

CONCLUSIONS

Compared with the IBS-D group, the IBS-C patients show greater prevalence of a wide range of symptoms referred to the upper and lower abdomen, musculoskeletal, and constitutional functions. These findings may be related to differences in autonomic or perceptual responses to visceral and somatic stimuli, and are likely to have implications for treatment responses in the two subgroups.

Motility of the small intestine

Motility of the small intestine is controlled by myogenic, neural, and hormonal mechanisms and is modulated by external influences such as meals, central nervous system activation, and immune factors. Small-bowel dysmotility is recognized in a number of diseases, but its precise role in symptom generation remains unclear in many instances. We review publications that in the year under review added to the basic understanding of small-intestinal motility as well as its alteration in disease.