Martin Raithel

Release of mast cell tryptase from human colorectal mucosa in inflammatory Bowel disease

Background: Histologic detection of mast cells cannot adequately reflect their function and state of activation, since degranulated mast cells may escape from histologic assessment. To better define the role of mast cells in inflammatory bowel disease, the spontaneous secretion of mast cell tryptase, a highly mast cell specific protease, was measured from colorectal samples. Methods: After detection of the initial basal tryptase release, gut mucosal samples were incubated in a modified Hanks/RPMI medium using a mucosa oxygenation system. Spontaneous tryptase secretion from 153 viable samples of 22 controls, 30 patients with Crohn disease (CD) and 19 with ulcerative colitis (UC) was followed over 4 h. Tryptase was measured by radioimmunoassay. Results: The rates of the initial basal tryptase release revealed that mast cell activation occurs during active inflammation in CD and UC. While the time course of tryptase release was similar in all three groups, spontaneous tryptase secretion (over 4 h) was found to be significantly enhanced and prolonged only in UC (P < 0.01 compared to controls), but not in CD. Conclusions: This study provides clear evidence from viable endoscopic colorectal samples that mast cell mediators were secreted during active inflammation in CD and UC. However, the extent of mast cell involvement and activation differs considerably between CD and UC. Significantly increased rates of tryptase secretion were found both in non-inflamed and inflamed tissue of UC, indicating that mast cell involvement is a typical feature of UC.

Mucosal Histamine Content and Histamine Secretion in Crohn’s Disease, Ulcerative Colitis and Allergic Enteropathy

Histamine exhibits various biological effects in inflammatory and immunological reactions. To further define its potential role in allergic enteropathy and inflammatory bowel disease, both gut mucosal histamine levels and histamine release from endoscopic biopsy samples were measured. Tissue histamine content resulted from addition of the released amount of histamine and the remaining part of tissue histamine. The results demonstrate highly elevated mucosal histamine levels of the large intestine in allergic enteropathy. In inflammatory bowel disease histamine content and secretion were found to be significantly increased particularly in affected mucosa of Crohns disease and ulcerative colitis than in unaffected tissue or in healthy controls. These findings give strong evidence that mast cell mediators like histamine play a role in the pathogenesis of these diseases. Mucosal histamine is thus concluded to contribute to the immuno-inflammatory reactions of the intestine found in these disease states and to reflect the degree of colonic inflammation in Crohns disease and ulcerative colitis.

Activation of NFκB Represents the Central Event in the Neoplastic Progression Associated with Barrett's Esophagus: A Possible Link to the Inflammation and Overexpression of COX-2, PPARγ and Growth Factors

The molecular mechanisms responsible for the progression of malignant transformation in Barretts esophagus (BE) are still poorly understood. This study was undertaken (1) to investigate the gene and protein expression of cyclooxygenase-2 (COX-2), peroxisome proliferator-activated receptor-gamma (PPARγ), interleukin-8 (IL-8), hepatocyte growth factor (HGF), gastrin, and its receptor (CCK-2) in the Barretts epithelium; (2) to analyze the activity of NFκB in Barretts esophagus with low-grade dysplasia; and (3) to assess the effects of PPARγ ligand (ciglitazone) and gastrin on cell proliferation in the cell line derived from esophageal adenocarcinoma (OE-33). COX-2, PPARγ, IL-8, HGF, gastrin, and CCK-2 expression levels relative to the control gene encoding GAPDH were analyzed by RT-PCR and Western blot in specimens of BE with low-grade dysplasia (n = 20) and compared with that in the normal squamous esophageal mucosa from the middle portion of the esophagus (n = 20). In vitro experiments included the incubation of cell line OE-33 with ciglitazone (1–15 μ M) and gastrin (100 nM). NFκB activity in biopsies specimens was measured by highly sensitive ELISA. COX-2, PPARγ, IL-8, HGF, gastrin, and CCK-2 expressions were significantly increased in BE compared with normal squamous esophageal mucosa. NFκB activity was significantly upregulated in BE. Ciglitazone inhibited cell proliferation of OE-33 cells as assessed by BrdU and this effect was attenuated partly by gastrin. (1) COX-2, PPARγ, HGF, gastrin, and its receptor are significantly upregulated in BE, suggesting a possible role for these factors in Barretts carcinogenesis; (2) the increased NFκB activity is probably linked to increased IL-8 and COX-2 expression; and (3) PPARγ ligands might be useful as a new therapeutic option in the prevention and treatment of Barretts carcinoma.

Urinary excretion of N-methylhistamine as a marker of disease activity in inflammatory bowel disease

OBJECTIVE:Mast cells are thought to participate in the pathogenesis of inflammatory bowel disease (IBD). In this study, urinary excretion of N-methylhistamine (UMH), a stable metabolite of the mast cell mediator histamine, was evaluated as an indicator of disease activity in patients with IBD.METHODS:Urinary excretion of UMH (μg/mmol creatinine × m2 body surface area) was measured by radioimmunoassay in 55 controls, 56 patients with Crohns disease, and in 36 patients with ulcerative colitis. Excretion rates were correlated with clinical, serological, and endoscopic disease activity, disease extent, and location.RESULTS:Urinary excretion of UMH was found to be significantly elevated in IBD. Patients with active Crohns disease (7.1 ± 4.2, p = 0.002 vs controls) and active ulcerative colitis (8.1 ± 4.8, p = 0.02 vs controls) had higher rates of UMH excretion than patients in remission (6.3 ± 3.8 and 5.2 ± 2.3, respectively) or controls (4.6 ± 1.9). In Crohns disease and ulcerative colitis, a significant correlation of UMH excretion with clinical disease activity was obtained (Crohns Disease Activity Index r2= 0.58, Clinical Activity Index r2= 0.57, p < 0.0001). Serologically, orosomucoid showed the best positive correlation with disease activity (Crohns Disease Activity Index r2= 0.80, Clinical Activity Index r2= 0.86, p < 0.0001), but UMH excretion was found to reflect disease activity more accurately than C-reactive protein (Crohns Disease Activity Index r2= 0.46, Clinical Activity Index r2= 0.42, p < 0.0001). No association between UMH excretion and disease type or localization could be found in Crohns disease. However, UMH excretion correlated strongly with endoscopic severity of inflammation in Crohns disease (Crohns Disease Endoscopic Index of Severity r2= 0.70, p < 0.0001) or disease extent in ulcerative colitis.CONCLUSIONS:Urinary excretion of the histamine metabolite UMH is enhanced in IBD. It appears to represent an integrative parameter to monitor clinical and endoscopic disease activity in IBD, which appears to be influenced most likely by mediators released from histamine-containing cells, such as intestinal mast cell subtypes.

Double-balloon-enteroscopy-based endoscopic retrograde cholangiopancreatography in post-surgical patients.

AIM To evaluate double balloon enteroscopy (DBE) in post-surgical patients to perform endoscopic retrograde cholangiopancreatography (ERCP) and interventions. METHODS In 37 post-surgical patients, a stepwise approach was performed to reach normal papilla or enteral anastomoses of the biliary tract/pancreas. When conventional endoscopy failed, DBE-based ERCP was performed and standard parameters for DBE, ERCP and interventions were recorded. RESULTS Push-enteroscopy (overall, 16 procedures) reached enteral anastomoses only in six out of 37 post-surgical patients (16.2%). DBE achieved a high rate of luminal access to the biliary tract in 23 of the remaining 31 patients (74.1%) and to the pancreatic duct (three patients). Among all DBE-based ERCPs (86 procedures), 21/23 patients (91.3%) were successfully treated. Interventions included ostium incision or papillotomy in 6/23 (26%) and 7/23 patients (30.4%), respectively. Biliary endoprosthesis insertion and regular exchange was achieved in 17/23 (73.9%) and 7/23 patients (30.4%), respectively. Furthermore, bile duct stone extraction as well as ostium and papillary dilation were performed in 5/23 (21.7%) and 3/23 patients (13.0%), respectively. Complications during DBE-based procedures were bleeding (1.1%), perforation (2.3%) and pancreatitis (2.3%), and minor complications occurred in up to 19.1%. CONCLUSION The appropriate use of DBE yields a high rate of luminal access to papilla or enteral anastomoses in more than two-thirds of post-surgical patients, allowing important successful endoscopic therapeutic interventions.

Guidelines on the management of IgE-mediated food allergies

S2k-Guidelines of the German Society for Allergology and Clinical Immunology (DGAKI) in collaboration with the German Medical Association of Allergologists (AeDA), the German Professional Association of Pediatricians (BVKJ), the German Allergy and Asthma Association (DAAB), German Dermatological Society (DDG), the German Society for Nutrition (DGE), the German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS), the German Society for Oto-Rhino-Laryngology, Head and Neck Surgery, the German Society for Pediatric and Adolescent Medicine (DGKJ), the German Society for Pediatric Allergology and Environmental Medicine (GPA), the German Society for Pneumology (DGP), the German Society for Pediatric Gastroenterology and Nutrition (GPGE), German Contact Allergy Group (DKG), the Austrian Society for Allergology and Immunology (OGAI), German Professional Association of Nutritional Sciences (VDOE) and the Association of the Scienti‰c Medical Societies Germany (AWMF)

Approach to suspected food allergy in atopic dermatitis

The following guideline of the “Arbeitsgruppe Nahrungsmittelallergie der DGAKI” (Task Force on Food Allergy of the German Society of Allergology and Clinical Immunology) and the ÄDA (“Ärzteverband Deutscher Allergologen”, Medical Association of German Allergologists) and the GPA (German Society of Pediatric Allergology) summarizes the approach to be taken when food allergy is suspected in patients with atopic dermatitis (neurodermatitis, atopic eczema). The problem is clinically relevant because many patients assume that allergic reactions against foods are responsible for triggering or worsening their eczema. It is important to identify those patients who will benefit from an elimination diet but also to avoid unnecessary diets. Elimination diets (especially in early childhood) are associated with the risk of malnutrition and additional emotional stress for the patients. The gold standard for the diagnosis of food‐dependent reactions is to perform placebo‐controlled, double‐blind oral food challenges because specific IgE, prick tests and history often do not correlate with clinical reactivity. This is particularly true in the case of delayed eczematous skin reactions. Diagnostic elimination diets should be used before an oral provocation test. If multiple sensitizations against foods are discovered in a patient, an oligoallergenic diet and a subsequent stepwise supplementation of the nutrition should be performed. If a specific food is suspected of triggering food allergy, oral provocation should be performed after a diagnostic elimination diet. As eczema‐tous skin reactions may develop slowly (i. e. within one or two day), the skin be inspected the day after the provocation test and that a repetitive test be performed if the patient has not reacted to a given food on the first day of oral provocation. The guideline discusses various clinical situations for patients with atopic dermatitis to facilitate differentiated diagnostic procedures.

The Differential Diagnosis of Food Intolerance

INTRODUCTION More than 20% of the population in industrialized countries suffer from food intolerance or food allergy. METHODS Selective literature search for relevant publications in PubMed and the Cochrane Library combined with further data from the interdisciplinary database on chronic inflammatory and allergic diseases of the Erlangen University Hospital. RESULTS The majority of cases of food intolerance (15% to 20%) are due to non-immunological causes. These causes range from pseudoallergic reactions to enzymopathies, chronic infections, and psychosomatic reactions that are associated with food intolerance. The prevalence of true food allergy, i.e., immunologically mediated intolerance reactions, is only 2% to 5%. CONCLUSIONS The differential diagnosis of food intolerance is broad. Therefore, a structured diagnostic algorithm with input from multiple clinical disciplines should be applied. The treatment consists of eliminating the offending substance from the diet as well as medications and psychosomatic support, when indicated.

Immunoglobulin E and eosinophilic cationic protein in segmental lavage fluid of the small and large bowel identify patients with food allergy.

OBJECTIVE:Members of the general population often assume that they suffer from food allergy, but the true prevalence is low. Testing for the diagnosis of food-related hypersensitivity entails laborious procedures, including GI endoscopy. Our objective was to develop an endoscopic screening approach for food allergy.METHODS:Endoscopically guided segmental lavage was performed in 11 patients with GI allergy and in 20 controls during lower GI endoscopy of the terminal ileum, the coecum, and the rectosigmoid. Eosinophilic cationic protein (ECP) and protein were measured in native lavage fluid, and immunoglobulin E (IgE) was also measured after a 10-fold lavage concentration.RESULTS:IgE/protein in lavage fluid from the coecum (0.055 ± 0.068 U/mg vs 0.003 ± 0.012 U/mg; p = 0.001) and the rectosigmoid (0.134 ± 0.170 U/mg vs 0.019 ± 0.042 U/mg; p < 0.05) was significantly elevated in patients with GI allergy. ECP/protein was significantly elevated at the terminal ileum (22.95 ± 37.67 μg/mg vs 7.09 ± 7.68 μg/mg; p < 0.05) and the rectosigmoid (23.66 ± 19.43 μg/mg vs 11.97 ± 16.39 μg/mg; p < 0.05). The combined use of GI lavage IgE and ECP as a diagnostic test for food allergy resulted in a sensitivity of 91% and a specificity of 80%.CONCLUSIONS:In endoscopically guided segmental lavage fluid, IgE and ECP/protein are increased in patients with food allergy. These measurements seem to offer an attractive diagnostic tool and may serve as a screening method.

Secretion and tissue content of eosinophil cationic protein in Crohn's disease.

To define further the role of eosinophils in the pathogenesis of Crohns disease, the secretion rate and tissue content of eosinophilic cationic protein (ECP) were measured in colorectal samples. Mucosal biopsies were obtained from 22 controls and 20 patients with Crohns disease during colonoscopy. After measurement of the initial basal ECP, release samples were incubated using a mucosa oxygenation system. Spontaneous and antiimmunoglobulin E (anti-IgE)-induced secretions of ECP were measured at different time points. For detection of the remaining tissue, ECP amount samples were mechanically homogenized after the incubation period. ECP measurement was performed by radioimmunoassay. Spontaneous ECP secretion rates during the incubation period were similar in all patient groups, whereas the initial basal ECP secretion was significantly increased in tissue affected by Crohns disease. After stimulation with anti-IgE, ECP secretion was increased two-fold in controls and three-fold in patients with Crohns disease. In tissue affected by Crohns disease, ECP levels were found to be significantly increased in most segments of the lower gastrointestinal tract with the highest ECP concentrations in affected mucosa. This functional study demonstrates an enhanced immunologically mediated ECP secretion and an accumulation of ECP in the intestinal mucosa of Crohns disease, indicating a local upregulation of eosinophils.