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Biomedical subjects

E Kankuri

Publications and source records attributed to E Kankuri.

7 recordsLinked to original sources

Probiotic supplementation improves tolerance to Helicobacter pylori eradication therapy--a placebo-controlled, double-blind randomized pilot study.

BACKGROUND: H. pylori is the major cause of chronic gastritis, and a risk factor for peptic ulcer and gastric cancer. AIM: To investigate the effect of probiotic supplementation on the tolerance and efficacy of H. pylori eradication treatment in a randomized, double-blind, placebo-controlled trial. METHODS: A total of 338 volunteers were screened for H. pylori infection. The eligibility criteria were met by 47 subjects whose H. pylori infection was verified at the outset and re-evaluated after the treatment by the 13C-urea breath test and by enzyme immunoassay serology. The subjects were randomized to receive probiotic therapy (Lactobacillus rhamnosus GG, L. rhamnosusLC705, Bifidobacterium breve Bb99 and Propionibacterium freudenreichii ssp. shermanii JS) or a placebo during H. pylori eradication and for 3 weeks following the treatment, and recorded their daily symptoms in a standardized diary. RESULTS: When the frequencies of new or aggravated symptoms were evaluated, no significant differences were found between the two groups for individual symptoms. However, the probiotic group showed less treatment-related symptoms as measured by the total symptom score change (P = 0.038) throughout the H. pylori eradication therapy in contrast to the placebo group. The H. pylori eradication rate was non-significantly higher in the group receiving probiotic therapy (91% vs. 79%, P = 0.42). In this group the recovery of probiotic bacteria in the faeces increased significantly (P < 0.001). CONCLUSIONS: In this pilot study, probiotic supplementation did not diminish significantly the frequency of new or aggravated symptoms during H. pylori eradication. However, our data suggest an improved tolerance to the eradication treatment when total symptom severity was taken into account. Furthermore, the results show that probiotic bacteria are able to survive in the gastrointestinal tract despite the intensive antimicrobial therapy.

Adult↗

Cell-cell contacts trigger programmed necrosis and induce cyclooxygenase-2 expression.

Necrosis was induced by cell-cell contacts of human dermal fibroblasts in three-dimensional culture. Dramatic induction of cyclooxygenase-2 (COX-2) expression was found throughout these necrotizing cell clusters, whereas no increase in expression of apoptosis markers was seen. The cells were rapidly committed to necrosis, and the process could not be reversed by allowing them to spread and adhere on a solid substrate. Induction of COX-2 expression was accompanied by greatly enhanced production of the prostaglandins E(2), I(2), and F(2alpha). When applied exogenously on necrotizing clusters, these prostaglandins delayed cell clustering and further enhanced COX-2 expression. Abolishing prostaglandin production by NS-398 or indomethacin reduced cell membrane damage (as measured by lactate dehydrogenase release into the culture medium). We also identified alpha-enolase-mediated plasminogen activation as the major extracellular proteolytic executor of necrotic cell death. In contrast to inhibition of COX-2, inhibition of plasminogen activation failed to inhibit membrane damage associated with necrosis. Intracellular proteolysis, by caspases, was shown to take part in COX-2 induction. Taken together, our results indicate that cell-cell contacts induce an actively programmed necrotic process that functionally involves COX-2, a known hallmark of inflammation and cancer.

Anti-Inflammatory Agents, Non-Steroidal↗

Suppression of pro-inflammatory cytokine release by selective inhibition of inducible nitric oxide synthase in mucosal explants from patients with ulcerative colitis.

BACKGROUND: In ulcerative colitis (UC), inflammatory damage is associated with increased production of pro-inflammatory cytokines and nitric oxide through the inducible nitric oxide synthase (iNOS) pathway. In an animal model of acute experimental colitis we have previously shown amelioration of inflammation with the highly selective iNOS inhibitor 1400W. The aim of the present study was to investigate the effects of selective iNOS inhibition on the production of pro-inflammatory cytokines by the colon mucosa in UC. METHODS: Inflamed and uninflamed mucosa from patients with severe UC were incubated with a highly selective iNOS inhibitor N-[3-(aminomethyl)benzyl]acetamidine (1400W), with a relatively selective cNOS inhibitor N(G)-nitro-L-arginine-methyl-esther (L-NAME), or with an NO-donor, S-nitroso-acetylpenicillamine (SNAP). Cytokine concentrations in the incubation medium were quantitated with ELISA. RESULTS: Compared to uninflamed mucosa there was an increase in iNOS protein and nitrotyrosine levels in inflamed mucosal samples. Immunolocalization of iNOS and nitrotyrosine showed their expression in inflammatory cells in the lamina propria. Expression of iNOS was also found in the epithelial brush border. Selective inhibition of iNOS suppressed the release of tumour necrosis factor alpha (TNF-alpha, by 66%) and interleukin-6 (IL-6, by 27%). The NO-donor, SNAP, augmented the secretion of TNF-alpha, IL-6 and IL-1-beta (by 62%, 52% and 175%, respectively) and decreased the release of IL-1 receptor antagonist (IL-1Ra, by 34%) by the inflamed mucosa. Moreover, in uninflamed samples, 1400W suppressed the production of TNF-alpha (by 69%) and incubation with SNAP decreased IL-6 concentrations by 48%. The cNOS over iNOS selective inhibitor L-NAME had no significant effects on the accumulation of cytokines. CONCLUSION: Selective inhibition of iNOS suppresses mucosal TNF-alpha and IL-6 release in active UC, whereas NO seems to exacerbate the inflammatory response. These results suggest that selective iNOS inhibition may have therapeutic promise in the treatment of UC.

Adult↗

Effects of a COX-2 preferential agent nimesulide on TNBS-induced acute inflammation in the gut.

In inflammatory bowel disease, increased production of prostaglandins by cyclooxygenase-2 (COX-2) contributes to bowel dysfunction, inflammatory edema, and hyperemia suggesting that inhibitors of COX-2 may have beneficial effect in gut inflammation. We compared the effects of nimesulide, a preferential COX-2 inhibitor, with those of indomethacin, acetylsalicylic acid (ASA), and dexamethasone in a 24-h model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in the rat. TNBS-induced colitis was associated with enhanced COX-2 expression in the gut and increased circulating concentrations of PGE2 metabolite (PGEM). Treatment with nimesulide (10 mg/kg), indomethacin (10 mg/kg), or dexamethasone (1 mg/kg) reduced plasma PGEM concentrations and edema in the inflamed bowel. In addition, nimesulide and dexamethasone treatments decreased neutrophil infiltration into the inflamed colon mucosa. ASA (10 mg/kg) did not have a significant effect on any of these measures of inflammation. None of the studied drugs reduced the size of inflammatory mucosal lesions in the colon. In TNBS-induced acute inflammation of the colon, nimesulide reduced the formation of inflammatory edema, probably by a mechanism related to inhibition of PGE2 production by COX-2 pathway. In addition, nimesulide inhibited neutrophil infiltration into inflamed mucosa mimicking the action of dexamethasone.

Acute Disease↗

Suppression of acute experimental colitis by a highly selective inducible nitric-oxide synthase inhibitor, N-[3-(aminomethyl)benzyl]acetamidine.

High concentrations of nitric oxide (NO) produced by the inducible nitric-oxide synthase (iNOS) are associated with ulcerative inflammation and disease activity in colitis. Therefore, inhibition of iNOS serves as a novel experimental approach to treat gut inflammation. The aim of the present study was to investigate the effects of a novel highly selective iNOS inhibitor, N-[3-(aminomethyl)benzyl]acetamidine (1400W), as compared with a nonselective NOS inhibitor, N(G)-nitro-L-arginine-methyl-ester (L-NAME), in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute colitis in the rat. Increased expression of iNOS protein and mRNA was found in acute TNBS-induced colitis along with neutrophil infiltration, inflammatory edema, and tissue damage. In a 24-h model of acute colitis, subcutaneous injections of 1400W (5 or 10 mg/kg t.i.d.) produced a 56 and 95% reduction in inflammatory edema formation, a 68 and 63% reduction in neutrophil infiltration (measured as myeloperoxidase activity), and a 19 and 26% decrease in the size of mucosal lesions as compared with vehicle treatment. Administration of L-NAME (35 mg/kg) failed to produce any significant beneficial effects as compared with vehicle treatment in this experimental model of acute colitis. Treatment with 1400W, a highly selective inhibitor of iNOS, reduced formation of edema, neutrophil infiltration, and macroscopic inflammatory damage in experimentally induced acute colitis in the rat. In contrast, nonselective nitric-oxide synthase inhibition with L-NAME provided no benefit. These results support the idea that selective iNOS inhibitors have a promise in the treatment of colitis.

Amidines↗

Induction of iNOS in a rat model of acute colitis.

Induction of colitis by 2,4,6-Trinitrobenzenesulphonic acid (TNB) in the rat is a widely used experimental model of inflammatory bowel disease. Action of TNB as a hapten, induces colitis involving infiltration of colonic mucosa by neutrophils and macrophages and increased production of inflammatory mediators. The aim of the present study was to measure nitric oxide synthase (NOS) activity and characterize relations between inducible NOS (iNOS) activity and other signs of inflammation in TNB-induced colitis. A profound and sustained increase in the activity of iNOS was found in the colon. The activity of NOS in the spleen was also increased, but remained at low levels as compared to those in colon. No increases in plasma nitrite + nitrate concentrations were found suggesting local rather than systemic induction of iNOS. The increase in iNOS activity in the colon was preceded by macroscopic inflammatory lesions, like hyperemia, ulcerations and edema formation as well as neutrophil accumulation in the gastric mucosa and increased circulating concentrations of PGE2 metabolite (PGEM). Concentrations of PGEM in the plasma and myeloperoxidase activity (MPO; marker of neutrophil infiltration) in the gut declined in 48h whereas increased iNOS activity and the macroscopic inflammatory lesions remained over the 72h follow-up period. The results demonstrate increased local iNOS activity in TNB-Induced colitis mimicking the situation in human inflammatory bowel disease.

Acute Disease↗