C. Mengoli

Bone Mass and Mineral Metabolism Alterations in Adult Celiac Disease: Pathophysiology and Clinical Approach

Osteoporosis affects many patients with celiac disease (CD), representing the consequence of calcium malabsorption and persistent activation of mucosal inflammation. A slight increase of fracture risk is evident in this condition, particularly in those with overt malabsorption and in postmenopausal state. The adoption of a correct gluten-free diet (GFD) improves bone derangement, but is not able to normalize bone mass in all the patients. Biomarkers effective in the prediction of bone response to gluten-free diet are not yet available and the indications of guidelines are still imperfect and debated. In this review, the pathophysiology of bone loss is correlated to clinical aspects, defining an alternative proposal of management for this condition.

Fasting and Postprandial Gastric Sensorimotor Activity in Functional Dyspepsia: Postprandial Distress Vs. Epigastric Pain Syndrome

OBJECTIVES:Little information is available on the mechanisms responsible for dyspeptic symptoms in postprandial distress syndrome (PDS), characterized by the presence of prevalently meal-related early satiation and fullness, and the epigastric pain syndrome (EPS), characterized by the prominent symptom of epigastric pain, generally not meal related. In a group of PDS patients, the presence of hypersensitivity to gastric distension in both fasting and postprandial phases was described as the main pathophysiological mechanism; on the contrary, we have no information on the pathophysiology of EPS.METHODS:Sixty Helicobacter pylori (HP)-negative, irritable bowel syndrome (IBS)-negative, and gastroesophageal reflux disease (GERD)-negative patients with functional dyspepsia according to Rome III criteria underwent symptom, anxiety, depression, and somatization evaluation, gastric barostat test, and gastric emptying time evaluation for solids. Fifteen age- and sex-matched healthy volunteers (HVs) were also enrolled as a control group.RESULTS:In PDS patients, the prevalence of both fasting and postprandial hypersensitivity was higher than in EPS patients, and the extent of postprandial reduction of discomfort threshold was significantly correlated with symptom severity. In EPS patients, gastric volume at fasting discomfort threshold and fasting compliance were significantly lower than in PDS patients. Gastric emptying time and gastric accommodation were similar between the two dyspeptic groups. Dyspeptic patients showed a higher prevalence of psychiatric disorders than HVs, but the prevalence was similar between PDS and EPS patients.CONCLUSIONS:Fasting and postprandial hypersensitivity characterize PDS patients and a reduction of gastric compliance is present in EPS patients. However, the pathophysiology of EPS appears more complex than PDS and further studies are needed to analyze central processing and integration of afferent pathways in order to clarify the role of the central nervous system in this condition.

Breath Methane Excretion Is not An Accurate Marker of Colonic Methane Production in Irritable Bowel Syndrome

OBJECTIVES:The role of colonic methane production in functional bowel disorders is still uncertain. In small samples of irritable bowel syndrome (IBS) patients, it was shown that methane breath excretion correlates with clinical presentation and delayed gastrointestinal transit time. The aim of this study was to evaluate the relationship between intestinal production and breath excretion of CH4 and to correlate CH4 production with the presence and the severity of symptoms, in a large cohort of IBS patients and in a group of healthy volunteers.METHODS:A group of 103 IBS patients and a group of 28 healthy volunteers were enrolled. The presence and severity of symptoms and gastrointestinal transit were evaluated in all subjects, who underwent breath H2/CH4 measurement for 7 h after lactulose to identify breath excretors of these gases; H2 and CH4 were also measured in rectal samples to identify colonic producers. Cumulative H2 and CH4 excretion and production were evaluated by the area under the time–concentration curve calculation (AUC).RESULTS:In IBS patients, CH4 was detected in rectal samples in 48 patients (47%), but only 27 of them (26% of the 103 enrolled patients) excreted this gas with breath. In CH4 producers, the prevalence and severity of symptoms and gastrointestinal transit time were not significantly different with respect to non-producers. IBS subtypes were homogeneously represented in CH4 producers and in non-producers. Healthy volunteers, compared with IBS patients, showed a significantly lower prevalence of CH4 excretion, whereas no difference was found in the prevalence of colonic CH4 production; moreover, in healthy volunteers compared with IBS, CH4 breath excretion and CH4 production were not different in quantitative terms.CONCLUSION:Our data show that colonic CH4 production is not associated with clinical presentation in IBS patients and does not correlate with symptom severity or with gastrointestinal transit time. Clinical inferences based on breath CH4 excretion should undergo an in-depth revision, as this method is not a good marker of CH4 colonic production.

Colonic hypersensitivity is a major determinant of the efficacy of bloating treatment in constipation-predominant irritable bowel syndrome

The pathophysiology of bloating is largely unknown, and many mechanisms have been proposed. An alteration of intestinal gas production may have a role in a subgroup of patients, but available data are conflicting. We have previously shown that hypersensitivity to colonic fermentation is associated with severe bloating in a subgroup of patients with low intestinal gas production. Accordingly, we evaluated whether modification of intestinal gas production improves bloating severity according to the presence of visceral hypersensitivity to colonic fermentation. Twenty-four IBS-C patients with severe bloating underwent intestinal gas production measurement by hydrogen breath test after lactulose, and a recto-sigmoid barostat test in order to evaluate sensitivity thresholds in a basal condition and after induction of colonic fermentation. The subjects were then randomly assigned to receive either rifaximin or placebo according to a double-blind, randomized, cross-over trial. Rifaximin induced an improvement of symptom severity. A post hoc analysis according to the presence of hypersensitivity to colonic fermentation shows that rifaximin induces a significant improvement in symptom severity only in normosensitive, hyperproducer patients. Modulation of colonic flora, in order to reduce fermentation, does not interfere with bloating severity in patients with visceral hypersensitivity, thus suggesting that in this subgroup of subjects gas production is not crucial for the onset of bloating.

The effect of gluten on intestinal fermentation, gastric and gallbladder emptying in healthy volunteers.

BACKGROUND The relationship between gluten ingestion and gastrointestinal tract function is a matter of debate. AIM We analysed the effect of gluten on gastric and gallbladder emptying and intestinal fermentation in healthy volunteers. METHODS Ultrasound measurement of gastric and gallbladder emptying after both gluten-containing and gluten-free meals was performed in 18 volunteers (8 women, age 25.0±2.5 years; BMI 22±1.9). Breath hydrogen excretion after a gluten-containing meal, a gluten-free meal and a gluten-free meal with added gluten powder was measured in 16 volunteers (10 women, age 25.2±2.7 years; BMI 22±1.8). The severity of symptoms was monitored. RESULTS Gluten presence in the meals was not recognised. Gastric emptying time was 81.6±13.8min after gluten-containing and 73.9±21.6min after gluten-free meals (p=0.11). Percentage ejection fraction after gluten-containing meals was 60±9% and 60.6±6% after gluten-free meals (p=0.68). Peak and cumulative hydrogen excretion were significantly higher after gluten-containing than after gluten-free meals (peak: 12.5±7.3 vs 6.5±5.1 parts-per-million, p<0.01; and cumulative: 2319±1720 vs 989±680 parts-per-million/minute, respectively; p<0.01). Adding gluten powder to the gluten-free meal did not modify fermentation. Symptoms were mild and not different after the meals. CONCLUSIONS In healthy volunteers, gluten may induce gastrointestinal alterations. Further studies are needed to clarify which patients could benefit from dietary modification.

Hydrogen breath test in patients with severe constipation: The interference of the mixing of intestinal content

The diagnostic accuracy of the hydrogen (H2) breath test might be reduced by the release of preformed H2, trapped in hard stools. Test solution ingestion might induce the mixing of colonic content and a false positive result. We studied severely constipated patients, at diagnosis and after the normalization of bowel function, to clarify whether this mechanism affects test results.

CS.2.1 AN ABNORMAL POSTPRANDIAL TONIC AND PHASIC RECTO-SIGMOID MOTOR ACTIVITY IS EVIDENT IN PATIENTS WITH MIGRAINE AND IRRITABLE BOWEL SYNDROME

AN ABNORMAL POSTPRANDIAL TONIC AND PHASIC RECTO-SIGMOID MOTOR ACTIVITY IS EVIDENT IN PATIENTS WITH MIGRAINE AND IRRITABLE BOWEL SYNDROME M. Di Stefano ∗ ,1, E. Pucci 2, C. Mengoli 1 , F. Racca1 , G. Sandrini 2, G. Nappi2, G. Corazza1 1First Department of Medicine, University of Pavia, IRCCS S. Matteo Hospital Foundation, Pavia; 2University Centre for Adaptive Disorders and Headache (UCADH), University of Pavia, IRCCS “C. Mondino”, Pavia