Helicobacter pylori Up-regulates Cyclooxygenase-2 mRNA Expression and Prostaglandin E2 Synthesis in MKN 28 Gastric Mucosal Cells in Vitro

Helicobacter pylori has been suggested to play a role in the development of gastric carcinoma in humans. Also, mounting evidence indicates that cyclooxygenase-2 overexpression is associated with gastrointestinal carcinogenesis. We studied the effect of H. pylori on the expression and activity of cyclooxygenase-1 and cyclooxygenase-2 in MKN 28 gastric mucosal cells. H. pylori did not affect cyclooxygenase-1 expression, whereas cyclooxygenase-2 mRNA levels increased by 5-fold at 24 h after incubation of MKN 28 cells with broth culture filtrates or bacterial suspensions from wild-type H. pylori strain. Also, H. pylori caused a 3-fold increase in the release of prostaglandin E2, the main product of cyclooxygenase activity. This effect was specifically related to H. pylori because it was not observed with Escherichia coli and was independent of VacA, CagA, or ammonia. H. pylori isogenic mutants specifically lacking picA or picB, which are responsible for cytokine production by gastric cells, were less effective in the up-regulation of cyclooxygenase-2 mRNA expression and in the stimulation of prostaglandin E2 release compared with the parental wild-type strain. This study suggests that development of gastric carcinoma associated with H. pylori infection may depend on the activation of cyclooxygenase-2-related events

Alimenti ed apparato digerente: la ricerca, il profitto, l'etica e la salute

Gli aspetti legati all'alimentazione, dalla produzione vegetale, alla trasformazione dei prodotti, ai regimi alimentari, agli effetti sulla salute, sono affrontati da ricercatori delle facoltà di agraria e di medicina. Sono trattati i seguenti temi: aspetti storico-antropologici, fattori sociali e genetici, fattori agronomici, fattori economici, attività antiossidante, funzioni digestive, OGM, qualità delle produzioni agro-alimentari, alimenti e patologie gastriche, micotossine, probiotici, biotecnologie, malnutrizion

Alcoholic beverages and gastric epithelial cell viability: effect on oxidative stress-induced damage

Alcohol is known to cause damage to the gastric epithelium independently of gastric acid secretion. Different alcoholic beverages exert different damaging effects in the stomach. However, this has not been systematically evaluated. Moreover, it is not known whether the non-alcoholic components of alcoholic beverages also play a role in the pathogenesis of gastric epithelial cell damage. Therefore, this study was designed to evaluate whether different alcoholic beverages, at a similar ethanol concentration, exerted different damaging effect in gastric epithelial cells in vitro. Moreover, we evaluated whether pre-treatment of gastric epithelial cells with alcoholic beverages prevented oxidative stress-induced damage to gastric cells. Cell damage was assessed, in MKN-28 gastric epithelial cells, by MTT assay. Oxidative stress was induced by incubating cells with xanthine and xanthine oxidase. Gastric cell viability was assessed following 30, 60, and 120 minutes incubation with ethanol 17.5-125 mg/ml(-1) or different alcoholic beverages (i.e., beer, white wine, red wine, spirits) at comparable ethanol concentration. Finally, we assessed whether pre-incubation with red wine (with or without ethanol) prevented oxidative stress-induced cell damage. Red wine caused less damage to gastric epithelial cells in vitro compared with other alcoholic beverages at comparable ethanol concentration. Pre-treatment with red wine, but not with dealcoholate red wine, significantly and time-dependently prevented oxidative stress-induced cell damage

Distribution, proliferation, and function of Paneth cells in uncomplicated and complicated adult celiac disease

Paneth cells, granulated epithelial cells located at the base of small bowel crypts, have a crucial role in innate immunity. Because controversies remain concerning Paneth cell numbers and function in celiac disease (CD), we quantified Paneth cells and human alpha-defensin (HD)-5 and HD-6 in 28 patients with uncomplicated CD, 8 patients with complicated CD (3 with ulcerative jejunoileitis, 2 with refractory sprue, and 3 with enteropathy-associated T-cell lymphoma), and 14 control subjects. Paneth cell numbers and proliferation did not differ in uncomplicated untreated and treated CD and control cases. However, the number of Paneth cells was significantly reduced in complicated CD. Mucosal HD-5 and HD-6 were comparable in uncomplicated untreated and treated CD and control cases. Ex vivo gliadin challenge of treated CD biopsy specimens had no effect on mucosal HD-5 and HD-6 transcripts. Paneth cell numbers and alpha-defensins are unchanged in the mucosa in uncomplicated CD. Further studies are needed to clarify the implications of reduction of numbers of Paneth cells in complicated CD