O. Karádi

Crohn's Disease Is Associated with Polymorphism of CARD15/NOD2 Gene in a Hungarian Population

Abstract: Crohns disease (CD) is commonly classified as an immune‐mediated disorder, but genetic and environmental factors seem to be important in its pathogenesis. Mutations within the CARD15/NOD2 gene have been associated with CD in the Caucasian population. The aim of our work was to investigate the allele frequency and clinical impact of the three common mutations in Hungarian CD patients and healthy controls. Seventy‐four CD patients and 107 controls were examined. The genotyping of the three common CARD15/NOD2 mutations (Arg702Trp, Gly908Arg, and Leu1007fsinsC) was carried out by restriction fragment length polymorphism (RFLP) and amplification refractory mutation system (ARMS) techniques. The demographic and clinical parameters were correlated with χ2 analysis. The overall prevalence of CARD15/NOD2 mutations in the Hungarian CD patients (33.78%) was significantly higher than in healthy control individuals (16.23%) (P < 0.025). The allele frequency of the Gly908Arg mutation did not differ, but the Arg702Trp and Leu1007fsinsC mutation were more common in CD patients than in controls. The onset of CD occurs about three years earlier in CARD15/NOD2 carriers. Carriage of the Arg702Trp and Leu1007fsinsC allele within the CARD15/NOD2 gene is associated with CD. These data are in line with similar findings showing a role of the CARD15/NOD2 protein in the etiopathogenesis of CD. The genotyping of these mutations might be used to identify high‐risk patients.

Modification of aspirin and ethanol-induced mucosal damage in rats by intragastric application of resiniferatoxin

The capsaicin analogue ‘resiniferatoxin’ (RTX) was used to investigate the role of capsaicin-sensitive sensory nerves in gastric mucosal injury caused by intragastric (ig) acidified aspirin (200 mg/kg in 2 ml of 0.15 N HCl) or ethanol (2 ml of 50% v/v or 96%) in pylorus-ligated rats. Animals were sacrificed 1, 2 and 4 h later, when gastric secretory responses, number and severity of mucosal lesions were calculated. Intragastric RTX (0.6–1.8 µg/kg) prevented mucosal injury in a dose-dependent manner induced by topical acidified aspirin. The protective effect lasted for 1h and was accompanied by inhibition of gastric acid secretion by RTX. RTX (0.6 and 1.0 µg/kg) co-administered with ethanol reduced mucosal injury caused by 50% ethanol; the protective effect of RTX being more apparent when the drug was given 15 min prior to 50% ethanol. Unexpectedly, RTX co-administered with absolute ethanol aggravated the ethanol-induced mucosal damage. It is concluded that capsaicin-sensitive sensory nerves mediated microcirculatory changes in gastroprotection and these involve inhibition of gastric acid secretion.

Hemochromatosis (HFE) gene mutations and hepatitis C virus infection as risk factors for porphyria cutanea tarda in Hungarian patients

Aim: It is not clear whether the mutations in hemochromatosis (HFE) gene and hepatitis C virus (HCV) infection act independently in the pathogenesis of porphyria cutanea tarda (PCT). The prevalence of both risk factors varies greatly in different parts of the world. PCT patients from Hungary were evaluated to assess both factors.

13C-Urea breath test is superior in sensitivity to detect Helicobacter pylori infection than either antral histology or rapid urease test.

There is no single technique which fulfils the criterion for a reference method to detect Helicobacter pylori (Hp) infection. The aim was to compare the results of antral histology (H), rapid urease test (U) and urea breath test (UBT) from antral biopsy samples in patients having gastric or duodenal lesions during upper GI endoscopy. We used the following methods: 1) biopsy specimens for histology (Warthin-Starry staining); 2) rapid urease test; and 3) 13C-urea breath test with infrared spectrometry. The total number of patients was 166 examined by H, U, and UBT. H, U and UBT were negative (-) in 64 patients and positive (+) in 51. The true positivity and false negativity (%, number of patients in parentheses) of each method based upon the positivity of the other two tests were: H+, U+ (54): UBT+, 94.4% (51) and UBT-, 5.6% (3); H+, UBT+ (57): U+, 89.5% (51) and U-, 10.5% (6); U+, UBT+ (65): H+, 78.5% (51) and H-, 21.5% (14). If Hp infection is considered to be positive when at least two tests detect the presence of Hp, UBT shows the highest sensitivity in comparison to histology of biopsy specimens and urease test. UBT is highly recommended as a screening test for Hp infection in patients presenting upper GI endoscopic alterations.

Stimulation of capsaicin-sensitive sensory peripheral nerves with topically applied resiniferatoxin decreases salicylate-induced gastric H+ back-diffusion in the rat

Capsaicin-sensitive sensory nerves (CSSN) exert local protective functions in the stomach and have been proposed to regulate gastric H+ back-diffusion. The present study aimed to evaluate the possible influence of stimulation of CSSN with the intragastrically (ig) applied capsaicin analogue, resiniferatoxin (RTX), on gastric H+ back-diffusion and mucosal injury caused by ig application of HCl (2 ml 0.15 mol/L) or acidified salicylate (200 mg/kg in 2 ml 0.15 mol/L HCl) after 1 or 2 h in the pylorus-ligated rat. Stimulation of CSSN with a low concentration (0.04 µg/ml) of RTX markedly decreased H+ back-diffusion caused by acidified salicylate. After acute bilateral truncal vagotomy or treatment with atropine sulphate, RTX did not inhibit gastric acid back-diffusion. Surgical vagotomy alone increased, while RTX or atropine markedly diminished, the development of gastric mucosal injury in these models. In saline-treated rats, RTX significantly reduced gastric secretory volume and acid output. The inhibitory effect lasted for 1 h. These data suggest an essential role for CSSN in regulation of gastric acid secretion and in maintaining the integrity of the gastric mucosa that appear to depend on intact vagal nerves.

Direct cellular effects of some mediators, hormones and growth factor-like agents on denervated (isolated) rat gastric mucosal cells

The brain-gut axis has an important role in the mechanism of gastric cytoprotection in vivo. The aim of this study was to evaluate the in vitro effect of protective agents without any central and peripheral innervation. A mixed population of rat gastric mucosal cells was isolated by the method of Nagy et al (Gastroenterology (1994) 77, 433-443). Cells were incubated for 60 min with cytoprotective drugs such as prostacyclin, histamine, pentagastrin and PL-10 substances (synthesized parts of BPC). At the end of this incubation cells were treated by 15% ethanol for 5 min. Cell viability was tested by trypan blue exclusion test and succinic dehydrogenase activity. The following results were obtained: 1) prostacyclin, histamine and pentagastrin had no direct cytoprotective effect on isolated cells; and 2) PL-10 substances significantly protected the cells against ethanol-induced cellular damage. This led to the following conclusions: 1) in the phenomenon of gastric cytoprotection only the growth factor-like agents have a direct cellular effect; and 2) the intact peripheral innervation is basically necessary for the development of mediators and hormone-induced gastric cytoprotection.

The key-role of vagal nerve and adrenals in the cytoprotection and general gastric mucosal integrity.

BACKGROUND Our laboratory group observed earlier that the gastric mucosal cytoprotective effect of prostacyclin (PGI(2)) disappeared after surgical vagotomy in rats. Similarly to this, the beta-carotene induced gastric cytoprotection disappeared in adrenalectomized rats too. AIMS In these studies we aimed to investigate the possible role of vagal nerve and adrenals in the development of gastric mucosal lesions induced by exogenously administered chemicals (ethanol, HCl, NaOH, NaCl and indomethacin), and on the effects of cytoprotective and antisecretory drugs (atropine, cimetidine), and scavengers (vitamin A and beta-carotene). METHODS The observations were carried out in fasted CFY strain rats. The gastric mucosal lesions were produced by intragastric (i.g.) administration of narcotising agents (96% ethanol; 0.6 M HCl; 0.2 M NaOH; 25% NaCl) or subcutaneously (s.c.) administered indomethacin (20 mg/kg) in intact, surgically bilaterally vagatomized, and adrenalectomized rats without or with glucocorticoid supplementation (Oradexon, 0.6 mg/kg given i.m. for 1 week). The gastric mucosal protective effect of antisecretory doses of atropine (0.1-0.5-1.0 mg/kg i.g.) and cimetidine (10-25-50 mg/kg i.g.), and vitamin A and beta-carotene (0.01-0.1-1.0-10 mg/kg i.g.) was studied. The number and severity of mucosal gastric lesions was numerically or semiquantitatively measured. In other series of observations the gastric acid secretion and mucosal damage were studied in 24 h pylorus-ligated rats without and with acute bilateral surgical vagotomy. RESULTS It was found that: (1) the chemical-induced gastric mucosal damage was enhanced in vagotomized and adrenalectomized rats, meanwhile the endogenous secretion of gastric acid, and the development of mucosal damage can be prevented by surgical vagotomy; (2) the gastric cyto- and general protection produced by the drugs and scavengers disappeared in vagotomized and adrenalectomized rats; (3) the gastric mucosal protective effects of drugs and of scavengers returned after sufficient glucocorticoid supplementation of the rats. CONCLUSION It has been concluded that the intact vagal nerve and adrenals have a key role in the gastric mucosal integrity, and in drugs- and scavengers-induced gastric cyto- and general mucosal protection.

Prevalence of the factor V Leiden mutation in human inflammatory bowel disease with different activity

BACKGROUND the developmental mechanism of inflammatory bowel disease (IBD) in patients is unknown, but it may be influenced by different environmental and genetical factors. AIMS of this study were: (1) to classify the IBD patients according the disease activity; and (2) to determine the presence of factor V Leiden mutation in IBD patients. PATIENTS AND METHODS the observation was carried out in 49 patients with Crohns disease (CD) and 29 patients with ulcerative colitis (UC). None of them had a history of thrombotic episodes. IBD was diagnosed by conventional clinical, endoscopic, radiological and histological criteria. The factor V Leiden mutation was detected by the polymerase chain reaction (PCR) method. Crohns disease activity index (CDAI) was evaluated using the method of the National Cooperative Crohns Disease Study. We determined the UC disease activity according to Truelove-Witts classification. RESULTS The prevalence of factor V Leiden mutation was increased in both populations of the patients to compare it with healthy persons (14.28 and 27.58% vs. 5.26%, n=7/49 and 8/29 vs. 3/57). The statistical analysis did not show a significant relationship between the CDAI or the Truelove-Witts grade in UC and the presence of Leiden mutation. CONCLUSION the presence of factor V Leiden mutation probably has a role in the development of IBD. Our results suggest a higher prevalence of this mutation in Central European patients than in Southern, Northern Europe or America, may be due to the genetical differences of these populations.

Vagal nerve and the gastric mucosal defense

An essential role for an intact vagal nerve has been proven in the development of gastric mucosal cyto- and general protection. On the other hand, chemically-induced (ethanol, HCl, indomethacin) gastric mucosal damage is enhanced after acute surgical vagotomy. The aims of this paper were to study the possible mechanisms of the vagal nerve in the development of gastric mucosal defense. The following questions were addressed: 1) effect of surgical vagotomy on the development of ethanol- (ETOH), HCl-, and indomethacin (IND)-induced gastric mucosal damage: 2) changes in the gastric mucosal defense by scavengers, prostacyclin and other compounds (small doses of atropine and cimetidine; 3) changes in the gastric mucosal vascular permeability due to chemicals; 4) effect of indomethacin in the ETOH and HCl models with and without surgical vagotomy; 5) changes in the gastric mucosal content of prostacyclin and PGE2 in the ETOH and HCl models after surgical vagotomy; and 6) changes in the role of SH-groups in gastric mucosal defense after surgical vagotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Participation of vanilloid/capsaicin receptors, calcitonin-gene-related peptide and substance P in gastric protection of omeprazole and omeprazole-like compounds.

The effects of omeprazole and different omeprazole-like compounds, associated with anti-ischaemic, antioxidant and poly(adenosine-diphosphate-ribose) polymerase (PARP) inhibitory properties, on the gastric acid secretion (4 h pylorus-ligated) and indomethacin-induced gastric mucosal damage connected with the specific immunohistochemical distribution of TRPV1, CRGP and SP during the effects of these compounds, were studied. The observations were carried out in CFY-strain rats (180–210 g), according to the standard methods and the above-mentioned parameters were studied in these experimental circumstances without and with application of different compounds. We found that: (1) all of the compounds dose-dependently inhibited the gastric acid secretion and mucosal damage; (2) the expression of TRPV1 receptor, CGRP and SP decreased significantly in both pylorusligated and indomethacin-treated animals and (3) the expression of TRPV1 and CGRP was reduced. Meanwhile, no change was obtained in SP expression during the gastric mucosal protection produced by omeprazole and omeprazole-like compounds. The conclusions were that (1) a functional overlap exists between the capsaicin-sensitive afferent and efferent vagal nerve during omeprazole effects; (2) chemical modification of omeprazole molecule offers a new pathway to obtain a new drug for the introduction in the clinical practice.