nan Stanghellini

Intestinal Serotonin Release, Sensory Neuron Activation, and Abdominal Pain in Irritable Bowel Syndrome

OBJECTIVES:Serotonin (5-hydroxytryptamine, 5-HT) metabolism may be altered in gut disorders, including in the irritable bowel syndrome (IBS). We assessed in patients with IBS vs. healthy controls (HCs) the number of colonic 5-HT-positive cells; the amount of mucosal 5-HT release; their correlation with mast cell counts and mediator release, as well as IBS symptoms; and the effects of mucosal 5-HT on electrophysiological responses in vitro.METHODS:We enrolled 25 Rome II IBS patients and 12 HCs. IBS symptom severity and frequency were graded 0–4. 5-HT-positive enterochromaffin cells and tryptase-positive mast cells were assessed with quantitative immunohistochemistry on colonic biopsies. Mucosal 5-HT and mast cell mediators were assessed by high-performance liquid chromatography or immunoenzymatic assay, respectively. The impact of mucosal 5-HT on electrophysiological activity of rat mesenteric afferent nerves was evaluated in vitro.RESULTS:Compared with HCs, patients with IBS showed a significant increase in 5-HT-positive cell counts (0.37±0.16% vs. 0.56±0.26%; P=0.039), which was significantly greater in patients with diarrhea-predominant IBS vs. constipation-predominant IBS (P=0.035). Compared with HCs, 5-HT release in patients with IBS was 10-fold significantly increased (P<0.001), irrespective of bowel habit, and was correlated with mast cell counts. A significant correlation was found between the mucosal 5-HT release and the severity of abdominal pain (rs=0.582, P=0.047). The area under the curve, but not peak sensory afferent discharge evoked by IBS samples in rat jejunum, was significantly inhibited by the 5-HT3 receptor antagonist granisetron (P<0.005).CONCLUSIONS:In patients with IBS, 5-HT spontaneous release was significantly increased irrespective of bowel habit and correlated with mast cell counts and the severity of abdominal pain. Our results suggest that increased 5-HT release contributes to development of abdominal pain in IBS, probably through mucosal immune activation.

Idiopathic myenteric ganglionitis underlying intractable vomiting in a young adult.

Inflammatory infiltration of intestinal myenteric plexuses (i.e. myenteric ganglionitis), along with severe intestinal motor abnormalities, may accompany paraneoplastic syndromes, neurological disorders and gastrointestinal infections, although rare cases can be idiopathic. In this report, we describe the case of a patient who presented with chronic intractable vomiting and weight loss associated with idiopathic myenteric ganglionitis mainly involving the stomach. Tissue analysis showed that the inflammatory infiltrate comprised T lymphocytes (CD4+ and CD8+), and peptide immunolabelling revealed a marked decrease of substance P/tachykinin immunoreactive staining in nerve fibres and myenteric neurones. Following systemic steroid therapy, the patients symptoms dramatically improved, and after one year of follow-up his general condition remains satisfactory. The possible mechanisms leading to symptom generation and gastric dysmotility in the context of an idiopathic myenteric ganglionitis are discussed.

Contrast-enhanced ultrasound in the differential diagnosis of exocrine versus neuroendocrine pancreatic tumors.

Objectives Contrast-enhanced ultrasound (CEUS) has been developed to better characterize the microvasculature of solid masses in several organs, including the pancreas. In this study, we assessed CEUS accuracy in differentiating exocrine from endocrine pancreatic tumors. Methods A total of 127 patients with single, undetermined pancreatic masses were prospectively examined with transabdominal ultrasound and CEUS, before surgical resection or percutaneous biopsy. Results Exocrine and endocrine pancreatic tumors showed different intralesional vascularization patterns: 98.9% (90/91) of exocrine tumors were hypoenhancing, whereas 95.8 % (23/24) of endocrine tumors had a hypervascular supply. A hypoenhancing pattern, indicative of ductal adenocarcinoma, had a significant (P < 0.001) diagnostic accuracy of 91.3% with a sensitivity of 96.8%, a specificity of 85.3%, a positive predictive value and a negative predictive value of 94.7% and 90.6%, respectively. The hyperenhancing pattern, indicative of endocrine tumors, had a significant (P = 0.031) diagnostic accuracy of 73.8% with a sensitivity of 83.3%, a specificity of 60.0%, a positive predictive value and negative predictive value of 83.3% and 60.0%, respectively. Conclusions Contrast-enhanced ultrasound has a valuable diagnostic accuracy in differentiating exocrine from endocrine pancreatic tumors, which is a fundamental step to address appropriate histological evaluation, therapeutic approach, and follow-up.

A 5-year experience of benign pancreatic hyperenzymemia.

Objective Benign pancreatic hyperenzymemia is characterized by a long-term increase of serum pancreatic enzymes in otherwise healthy subjects. This study was designed to determine (a) whether all pancreatic enzymes are elevated, (b) the extent of each enzyme increase, (c) the relative frequency of the familial form, and (d) the relative frequencies of pancreatic and salivary hyperamylasemia and macroamylasemia. Methods Two hundred seven asymptomatic subjects with benign pancreatic hyperenzymemia were studied during the 5-year period. Serum amylase, isoamylase, and lipase levels were assessed by immunoenzymatic assays. Results Most (n = 183; 88.4%) patients had benign pancreatic hyperenzymemia; 155 (74.9%) patients had an abnormal increase of all 3 enzymes, 15 (7.2%) patients of only lipase, and 13 (6.3%) patients of only amylase and pancreatic isoamylase. Lipase levels were the highest (1.1–21 times above upper limit). Of the 183 subjects, 72 were members of 35 different families, 15 (7.2%) had increased salivary amylase, and 9 (4.3%) had macroamylasemia. Wide day-to-day fluctuations of pancreatic enzymes, including falls within the reference ranges, were recorded. Conclusions All enzymes were increased in benign pancreatic hyperenzymemia, with lipase showing the highest elevation. Doctors should reassure patients about the benign nature of this condition and limit repeating useless examinations.

The diagnostic challenge of symptomatic uncomplicated diverticular disease.

Colonic diverticulosis is a common condition in Western industrialized countries occurring in up to 65% of people over the age of 60 years. Only a minority of these subjects (about 10-25%) experience symptoms, fulfilling Rome III Diagnostic Criteria for irritable bowel syndrome (IBS) diagnosis (IBS-like symptoms) in 10% to 66% of cases. Symptomatic uncomplicated diverticular disease (SUDD) is a syndrome characterized by recurrent abdominal symptoms attributed to diverticula in the absence of macroscopically evident alterations other than the presence of diverticula. Due to the different peak of incidence, the overlap between SUDD and IBS is predominantly present in middle-aged or older patients. In these cases, it is very complex to establish if the symptoms are related to the presence of diverticula or due to an overlapping IBS. In fact, the link between gastrointestinal symptoms and diverticula is unclear, and the mechanism by which diverticula may induce the development of IBS-like symptoms remains to be elucidated. Currently, the etiology and pathophysiology of SUDD, particularly when IBS-like symptoms are present, are not completely understood, and thus these two entities remain a diagnostic challenge not only for the general practitioner but also for the gastroenterologist. Although many issues remain open and unresolved, some minimize the importance of a distinction of these two entities as dietary and pharmacological management may be largely overlapping.