Mast cell-dependent excitation of visceral-nociceptive sensory neurons in irritable bowel syndrome

BACKGROUND & AIMS

Intestinal mast cell infiltration may participate to abdominal pain in irritable bowel syndrome (IBS) patients. However, the underlying mechanisms remain unknown. We assessed the effect of mast cell mediators released from the colonic mucosa of IBS patients on the activation of rat sensory neurons in vitro.

METHODS

Colonic mast cell infiltration and mediator release were assessed with quantitative immunofluorescence and immunoenzymatic assays. The effect of mucosal mediators was tested on mesenteric sensory nerve firing and Ca(2+) mobilization in dorsal root ganglia in rats.

RESULTS

Mediators from IBS patients, but not controls, markedly enhanced the firing of mesenteric nerves (14.7 +/- 3.2 imp/sec vs 2.8 +/- 1.5 imp/sec; P < .05) and stimulated mobilization of Ca(2+) in dorsal root ganglia neurons (29% +/- 4% vs 11% +/- 4%; P < .05). On average, 64% of dorsal root ganglia responsive to mediators were capsaicin-sensitive, known to mediate nociception. Histamine and tryptase were mainly localized to mucosal mast cells. IBS-dependent nerve firing and Ca(2+) mobilization were correlated with the area of the colonic lamina propria occupied by mast cells (r = 0.74; P < .01, and r = 0.78; P < .01, respectively). IBS-dependent excitation of dorsal root ganglia was inhibited by histamine H(1) receptor blockade and serine protease inactivation (inhibition of 51.7%; P < .05 and 74.5%; P < .05; respectively).

CONCLUSIONS

Mucosal mast cell mediators from IBS patients excite rat nociceptive visceral sensory nerves. These results provide new insights into the mechanism underlying visceral hypersensitivity in IBS.

Enteric neuropathology of congenital intestinal obstruction: A case report

Experimental evidence indicates that chronic mechanical sub-occlusion of the intestine may damage the enteric nervous system (ENS), although data in humans are lacking. We here describe the first case of enteric degenerative neuropathy related to a congenital obstruction of the gut. A 3-year and 9-mo old girl began to complain of vomiting, abdominal distension, constipation with air-fluid levels at plane abdominal radiology. Her subsequent medical history was characterized by 3 operations: the first showed dilated duodeno-jejunal loops in the absence of occlusive lesions; the second (2 years later) was performed to obtain full-thickness biopsies of the dilated intestinal loops and revealed hyperganglionosis at histopathology; the third (9 years after the hyperganglionosis was identified) disclosed a Ladd's band which was removed and the associated gut malrotation was corrected. Repeated intraoperative full-thickness biopsies showed enteric degenerative neuropathy along with reduced interstitial cells of Cajal network in dilated loops above the obstruction and a normal neuromuscular layer below the Ladd's band. One year after the latest surgery the patient tolerated oral feeding and did well, suggesting that congenital (partial) mechanical obstruction of the small bowel in humans can evoke progressive adaptive changes of the ENS which are similar to those found in animal models of intestinal mechanical occlusion. Such ENS changes mimic neuronal abnormalities observed in intestinal pseudo-obstruction.

Postinfectious gastroparesis related to autonomic failure: a case report

BACKGROUND AND AIM

Severe dysautonomia may be secondary to viral infections, resulting in impaired autoimmune, cardiovascular, urinary and digestive dysfunction. Herein, we present a case of a 31-year-old white female patient who had severe gastroparesis related to autonomic failure following an episode of acute gastroenteritis. This seems to be the first report providing thorough assessment of the enteric and autonomic nervous system by analysis of full-thickness small intestinal biopsies, cardiovagal testing and autopsy.

HOSPITAL COURSE

This patient affected by a severe gastroparesis was treated with antiemetics, prokinetics, analgesics and gastric electrical stimulation to control symptoms. Nutritional support was made using jejunal feeding tube and, in the final stage of disease, with total parenteral nutrition. Autonomic studies revealed minimal heart rate variability and a disordered Valsalva manoeuvre although the enteric nervous system and the smooth muscle layer showed a normal appearance. Hospital courses were complicated by episodes of bacteraemia and fungemia. Serum antiphospholipid antibodies were noted but despite anticoagulation, she developed a pulmonary embolism and shortly thereafter the patient died. Autopsy revealed acute haemorrhagic Candida pneumonia with left main pulmonary artery thrombus. Sympathetic chain analysis revealed decreased myelinated axons with vacuolar degeneration and patchy inflammation consistent with Guillain-Barre syndrome. The evaluation of the enteric nervous system in the stomach and small bowel revealed no evidence of enteric neuropathy or myopathy.

CONCLUSION

A Guillain-Barre-like disease with gastroparesis following acute gastroenteritis is supported by physiological and autonomic studies with histological findings.

Interactions between commensal bacteria and gut sensorimotor function in health and disease

Commensal bacteria inhabiting the human intestine (i.e., intestinal microflora) participate in the development and maintenance of gut sensory and motor functions, including the promotion of intestinal propulsive activity. On the other hand, intestinal motility represents one of the major control systems of gut microflora, through the sweeping of excessive bacteria from the lumen. There is emerging evidence indicating that changes in this bidirectional interplay contribute to the pathogenesis of gut diseases, such as small intestinal bacterial overgrowth and intestinal pseudo-obstruction. Recent interest has also been directed to the potential role of intestinal microflora in the pathogenesis of the irritable bowel syndrome. Although the status of intestinal microflora in the irritable bowel syndrome remains unsettled, small intestinal bacterial overgrowth (as detected with breath testing) and increased fermentation of foods with gas production, provide indirect evidence that microflora may contribute to symptom generation in irritable bowel syndrome. The potential benefit of antibiotic and probiotic therapy is currently under investigation and opens new perspectives in irritable bowel syndrome treatment.

Idiopathic achalasia is not allelic to alacrima achalasia adrenal insufficiency syndrome at the ALADIN locus

BACKGROUND

Evidence indicates that patients with familial achalasia associated with Allgrove or triple-A syndrome (i.e. alacrima, achalasia and adrenocorticotropin-resistant adrenal insufficiency with neurological impairment) have mutations of the alacrima achalasia adrenal insufficiency syndrome (AAAS) gene.

AIM

The present study was aimed at identifying possible AAAS gene mutations in patients with established idiopathic non-familial achalasia.

METHODS

Genomic DNA of 41 patients was isolated from peripheral blood cells using standard methods. The 16 exons of the AAAS gene (or ALADIN) were screened for mutations using the denaturing high-performance liquid chromatography method.

RESULTS

Four heterozygous nucleotidic variations have been identified in patients with idiopathic achalasia, among which three were exonic conservative polymorphisms [i.e. D138D (GAT-->GAC), L227L (TTG-->CTG) and F285F (TTC-->TTT) in exons 5, 7 and 9, respectively]. The fourth nucleotidic variation was located in intron 13 (IVS14-23delT). All variants have been regarded as polymorphisms resulting in a normal ALADIN protein since they are either conservative or lying outside the consensus splice sites.

CONCLUSIONS

Our data do not support a pathogenetic role for common AAAS gene mutations in patients with idiopathic achalasia as seen in Allgrove syndrome. These findings suggest the participation of different mechanisms in the pathogenesis of idiopathic achalasia.

Inflammation of the gastric cardia in children with symptoms of acid peptic disease

OBJECTIVES

To assess the severity and causes of inflammation of the gastric cardia in children undergoing endoscopy for symptoms of acid peptic disease.

STUDY DESIGN

Patients undergoing upper gastrointestinal endoscopy for symptoms of acid peptic disease had biopsies from gastric cardia, gastric, and esophageal sites, and 24-hour intraesophageal pH monitoring. Gastric cardia was defined at endoscopy as the anatomic zone from the squamocolumnar junction to 0.5 cm below it. Severity of gastric cardia inflammation was scored 0 to 9 according to densities of inflammatory cells and epithelial abnormalities in surface and pit epithelium. A score > or =2 was considered positive.

RESULTS

Forty-seven children (median age, 6.5 years; range, 3-15) had Helicobacter pylori infection, gastroesophageal reflux disease (GERD), or both. In 22 patients, H pylori was detected in cardiac biopsies by rapid urease test and histology; it was detected also in the corpus and antrum in only seven of the 22. No patient had H pylori in gastric corpus/antrum without having the organism at the cardia as well. In 12 H pylori-positive patients, GERD was also diagnosed. Twenty-five patients had GERD and no H. pylori infection. Severity score was 3.8+/-0.8 in the H pylori group and 2.08+/-0.9 in the GERD alone group (P<.001); however, there was no difference in reflux index (24-hour % of gastroesophageal reflux) between the two groups. In neither group was correlation found between reflux index and severity score (H pylori, r=0.22; GERD alone, r=0.31; NS) nor between cardia inflammation and esophagitis grade (H pylori, r=0.37; GERD alone, r=0.22; NS).

CONCLUSIONS

In children with symptoms of acid peptic disease, inflammation of the gastric cardia does occur. It is more severe when the cardiac zone is infected with H pylori than in its absence. Of major practical significance is the finding that the gastric cardia is a highly sensitive site for the detection of H pylori infection.

New therapeutic approach in the management of intestinal disease: probiotics in intestinal disease in paediatric age

Current evidence supports the view that oral administration of probiotics may be of therapeutic usefulness in several clinical disorders by reestablishing normal flora in the gastrointestinal tract. These entities include inflammatory and infectious diseases of the gut as well as extraintestinal disorders (such as atopic eczema) in which a defective intestinal permeability plays a role. The probiotic effects are attributed to restoration to normal of increased intestinal permeability, unbalanced gut microecology, improved immunological gut barrier function, downregulation of the intestinal inflammatory responses with reduced generation of proinflammatory cytokines. Entities for which the impact of probiotic administration can be considered as proven are Rotavirus diarrhoea, Clostridium difficile diarrhoea, post-antibiotic diarrhoea, allergic diseases. On the other hand, entities for which administration of probiotics is considered under investigation are inflammatory bowel disease, necrotizing enterocolitis, cystic fibrosis, small bowel bacterial contamination, functional gastrointestinal disorders. The value of probiotics as therapy for a variety of gastrointestinal disorders in childhood still needs to be investigated in detail, through well controlled and rigorous studies, including a placebo group and strict criteria of randomisation. Much work needs to be done in this area by clearly defining indications, delivery system, costs, safety long-term effects.

Domperidone is more effective than cisapride in children with diabetic gastroparesis

BACKGROUND

Disorders of gastrointestinal motility are commonly detected in patients with insulin-dependent diabetes mellitus and are associated with significant morbidity. They contribute to poor metabolic control of diabetes.

AIM

To assess the effect of an 8-week course of domperidone or cisapride on gastric electrical activity, gastric emptying time and dyspeptic symptoms in children with insulin-dependent diabetes mellitus and gastroparesis.

METHODS

Dyspeptic symptoms were assessed by a score system, gastric emptying time was measured by ultrasonography and gastric electrical activity was obtained by electrogastrography. Fourteen children received domperidone and 14 received cisapride. The median (range) ages were 11.6 years (5-15 years) and 12 years (6-16.9 years), respectively. Symptom assessment, ultrasonography and electrogastrography were repeated at the end of the trial. Fasting and fed (180 min after feeding) glycaemia and haemoglobin A, C (HbA1c) levels were also measured.

RESULTS

At the end of the trial both groups showed a significant decrease in symptomatic score; however, the score was markedly lower in the domperidone group than in the cisapride group (P < 0.01). Domperidone was significantly more effective than cisapride in reducing the gastric emptying time (P < 0.05), normalizing gastric electrical activity (P < 0.05) and decreasing the prevalence of episodes of gastric dysrhythmia (P < 0.01). Domperidone was also more effective than cisapride in improving diabetic metabolic control. No potentially drug-related adverse effects occurred.

CONCLUSIONS

In children with insulin-dependent diabetes mellitus complicated by dyspeptic symptoms and gastroparesis, domperidone is superior to cisapride in reversing gastric emptying delay and gastric electrical abnormalities, as well as in improving dyspeptic symptoms and diabetic metabolic control.

Role of drug therapy in the treatment of gastro-oesophageal reflux disorder in children

Gastro-oesophageal reflux (GOR) is the effortless passage of gastric contents into the distal oesophagus. It can be classified as functional (or symptomatic), in which the infant remains free from disease, or a pathological (GOR disease, GORD), in which gastrointestinal, respiratory or neurobehavioural signs occur with intraoesophageal acidification and the development of oesophagitis. Functional or symptomatic GOR is successfully treated by conservative measures and does not require investigative diagnostic tools; however, both drug administration and an investigative approach are mandatory in patients with GORD. There is currently a great range of proven therapeutic options for GORD that are directed at counteracting the pathogenetic components of the disorder. In this report we discuss the role of different drug classes for treating GORD in children. The choice of therapy for GORD depends upon the severity of signs and the degree of oesophagitis. The presence of oesophagitis, as documented by endoscopy, suggests the use of antisecretory drugs; H2 receptor antagonists are the first-line agents. Nevertheless, individuals with refractory disease or those patients requiring potent inhibition of acid secretion (for example, GORD with respiratory involvement) can be given proton pump inhibitors. Other groups of patients who need potent inhibition of acid secretion are children with neurological dysfunction and those with Barrett's oesophagus. It is still unclear whether patients with frequent relapses are candidates for long term administration of antisecretory drugs or for surgical fundoplication.