Th response to Helicobacter pylori differs between patients with gastric ulcer and duodenal ulcer

Isolation of lymphocytes from the human gastric mucosa

Flow cytometry is widely used for lymphocyte immunophenotyping in clinical settings. However, few studies have applied it for analyzing lymphocytes of the gastric mucosa. This review offers an overview of methodologies for isolating lymphocytes from the human stomach. Previously reported articles were reviewed, focusing on procedures for isolating human gastric mucosal lymphocytes. Helicobacter pylori-associated peptic diseases and gastric cancer are two major subjects of research in this field. Enzymatic dissociation, mechanical dissociation, or a combination of the two have been used to isolate lymphocytes from the stomach. Intra-epithelial and lamina propria lymphocytes were separately isolated in several studies. We also summarize the history and present trends in analyzing lymphocytes in patients with gastric disease.

Therapy with omeprazole modulates regulatory T cell/T helper 17 immune response in children with duodenal ulcers

The purpose of this study was to determine the effect of omeprazole on the regulatory T cell (Treg) and T helper 17 (Th17)-mediated response in patients with duodenal ulcers (DUs). DU patients were randomly divided into omeprazole and colloid bismuth subcitrate treatment groups. The ratios of Th17 and Treg in peripheral blood mononuclear cells (PBMCs) were measured. Cytokine production and Foxp3⁺- and RORγt-positive cells were detected. The expressions of STAT3, p-STAT3, STAT5 and p-STAT5 were detected by Western blot. The results showed that DU patients had an imbalanced Treg/Th17 response, as reflected by the higher IL-17 level and Th17 ratio and lower IL-10 level and Treg proportion in serum compared with those in the healthy volunteers. The administration of omeprazole to the patients significantly increased Treg and IL-10 levels and reduced Th17 and IL-17 levels. Omeprazole markedly increased the number of Foxp3-positive cells, decreased the number of RORγt-positive cells and restored the balanced ratio of IL-10/IL-17 in the ulcer tissue. Interestingly, we observed a negative correlation between the ratios of Treg/Th17 and the pathological scores in damaged tissues. Of note, H. pylori-infected PBMCs showed decreased Treg and an increased Th17 proportion, which could be reversed by omeprazole. Finally, omeprazole increased the expression of p-STAT5 and reduced the level of p-STAT3 without any effects on the total expression of STAT5 and STAT3. Our data suggest that omeprazole treatment restores the equilibrium of the Treg/Th17-mediated response in DU patients. Moreover, the modulation of p-STAT3 and p-STAT5 expression by omeprazole induced balanced polarisation of Treg/Th17.

Increased expression and cellular localization of lipocalin-type prostaglandin D synthase in Helicobacter pylori-induced gastritis

Immunological responses in the host can result in different disease outcomes of Helicobacter pylori-induced gastritis. Prostaglandin E2 derived from cyclooxygenase (COX) and prostaglandin E synthase contribute to gastric protection. Recently, prostaglandin D2 was shown to be involved in host immunity by chemotactic activity through chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2), but its role in H. pylori-induced gastritis has not been clarified. We determined the expression levels of mRNAs for haematopoietic PGD synthase (H-PGDS) and lipocalin-type PGDS (L-PGDS), MIP-1 alpha, IFN-gamma, IL-4, and CDX2 in H. pylori-induced gastritis mucosa by quantitative RT-PCR. We found that L-PGDS was constitutively expressed in the epithelium of the glandular base. L-PGDS, but not H-PGDS, was induced on fibroblasts close to infiltrating cells in the H. pylori-infected gastric mucosa. These fibroblasts co-expressed COX-2. The level of L-PGDS mRNA expression decreased as gastritis became more severe. In most of the H. pylori-infected gastric mucosa, CCR5(+) cells had more actively infiltrated than had CRTH2(+) cells. However, the expression level of IFN-gamma was lower in the mucosa of the CRTH2(+) cells-dominantly infiltrating group than that of the less CRTH2-infiltrating group. Exogenously added PGD2 decreased the H. pylori-induced expression of IFN-gamma in peripheral blood mononuclear cells in vitro. The data suggest that PGD2 derived from the gastric mucosa and fibroblasts plays protective roles against inflammatory changes in H. pylori-induced gastritis.

Helicobacter pylori induces gastric mucosal intestinal metaplasia through the inhibition of interleukin-4-mediated HMG box protein Sox2 expression

Helicobacter pylori is a major cause of the transdifferentiation into intestinal metaplasia that may develop gastric cancer. However, the molecular pathogenesis of this transdifferentiation is poorly understood. A SRY-related HMG box protein Sox2 is an essential transcription factor of organ development in brain, lung, and stomach. Our aim of this study was to investigate the mechanism responsible for regulation of Sox2 in host Th1-dominant response to H. pylori. Sox2 protein was immunohistochemically expressed in both human oxyntic and pyloric glands with H. pylori infection, but not in intestinal metaplasia. Western immunoblotting of gastric epithelial cell lines showed that IL-4, a Th2-related cytokine, dose dependently enhanced Sox2 expression among H. pylori infection-mediated cytokines. Small changes of Sox2 expression were observed after each treatment with IFN-gamma, IL-1beta, or TNF-alpha. IL-4-mediated Sox2 induction was suppressed by the inhibition of STAT6 activation with STAT6 RNA interference, and electrophoretic mobility shift assay indicated that activation of the Sox2 promoter by IL-4 occurred through the action of STAT6. Furthermore, H. pylori and IFN-gamma inhibited the phosphorylation of STAT6, resulting in the suppression of IL-4-mediated Sox2 expression. Immunohistochemical analyses showed significantly the suppressed STAT6 activity in H. pylori-infected human gastric mucosa. Additionally, downregulation of Sox2 by knockdown experiments led to intestinal phenotype with expressions of Cdx2 and MUC2. These results suggest that H. pylori and IFN-gamma interfere with the differentiation into oxyntic and pyloric glands by the downregulation of Sox2 on IL-4/STAT6 signaling, which may contribute to the transdifferentiation into intestinal metaplasia.

Promoter polymorphisms of IL2, IL4, and risk of gastric cancer in a high-risk Chinese population

Interleukin 2 (IL2) is a typical Th1 cytokine, and interleukin 4 (IL4) is an inducible Th2 cytokine. These cytokines are critical mediators of the Th1/Th2 balance and apoptosis potential and involved in the process of inflammation-mediated carcinogenesis in human organs, including the gastrointestinal tract. Therefore, we tested the hypothesis that functional variants in IL2 and IL4 were associated with risk of gastric cancer by genotyping two promoter polymorphisms in IL2 G-330T (rs2069762) and IL4 T-168C (rs2070874) in a case-control study of 1045 patients with incident gastric cancer and 1100 cancer-free controls in a high-risk Han Chinese population. We found that, compared with the IL4 -168TT genotype, heterozygous -168TC and combined -168TC/CC genotypes were associated with a significantly decreased gastric cancer risk [adjusted odds ratio (OR) = 0.81, 95% confidence interval (CI) = 0.67-0.98 for -168TC; OR = 0.83, 95% CI = 0.69-1.00 for -168TC/CC, respectively]. Furthermore, this significant protective effect was more evident for gastric cardia cancer patients (adjusted OR = 0.73, 95% CI = 0.56-0.95 for -168TC/CC vs. -168TT). For IL2 G-330T, subjects carrying GT/TT genotypes also had a significantly reduced risk of gastric cardia cancer (adjusted OR = 0.68, 95% CI = 0.46-0.99), compared with those carrying the GG genotype. Our results indicate that IL4 T-168C and IL2 G-330T promoter polymorphisms may contribute to the etiology of gastric cardia cancer in Chinese populations.

Persistent H. pylori colonization in early acquisition age of mice related with higher gastric sialylated Lewis x, IL-10, but lower interferon-γ expressions

Background

H. pylori infection is less prevalent in childhood. This study validated whether the rates of H. pylori colonization depend on different acquisition ages, and correlate with the different gastric Lewis antigens or cytokine expressions after H. pylori acquisition.

Methods

We applied a young (7-day-old) C57BL/6 mice group (n = 50) and adult (6-week-old) C57BL/6 mice group (n = 50). In each group, 30 mice were challenged with H. pylori and 20 mice served as naïve control. The success of H. pylori colonization was assessed on the 2^nd week and the 8^th week, respectively. The intensity of the Lewis x, sialylated Lewis x(sialyl-Le^x), and cytokine expressions, including TNF-α, IFN-γ, IL-6, IL-10, and IL-1β, were immunochemically stained and graded.

Results

On the 2^nd week after H. pylori challenge, the colonization rates of H. pylori were similar between the young mice group and the adult mice group (89% vs. 100%, P > 0.05). However, on the 8^th week, the H. pylori colonization rate was significantly lower in the young mice group than in the adult mice group (53% vs. 95%, P = 0.003). On the 8^th week, the young mice with a persistence of H. pylori colonization had higher sialyl-Le^x, higher IL-10, and lower IFN-γ than those of the mice that lost colonization during the 2^nd to the 8^th week (P < 0.05).

Conclusion

The persistence of H. pylori colonization could be an acquisition-age determinant process. After H. pylori exposure at an early acquisition age, the host response with a higher sialyl-Le^x and IL-10, but a lower IFN-γ correlates to the consequent persistence of H. pylori colonization.

Mechanism for gastric cancer development by Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection plays a crucial role in the development of gastric cancer. There are two major pathways for the development of gastric cancer by H. pylori infection: the indirect action of H. pylori on gastric epithelial cells through inflammation, and the direct action of the bacteria on epithelial cells through the induction of protein modulation and gene mutation. Both pathways work together to promote gastric carcinogenesis.

Alterations in antral cytokine gene expression in peptic ulcer patients during ulcer healing and after Helicobacter pylori eradication

Earlier studies have shown that the antral immune response in Helicobacter pylori infection has a mixed Th1-Th2-T-regulatory profile. After eradication, a chronic inflammation remains in some patients, but a follow-up study with a comprehensive cytokine profile in has not previously been published. Twelve patients with H. pylori positive peptic ulcer disease (five antral and seven duodenal) were enrolled and cytokine gene expressions in antral biopsies were determined (1) at entry, (2) after resolving the ulcer with proton pump inhibitor (PPI) treatment and (3) after eradication. The second endoscopy was performed 4 weeks after ending the PPI treatment, and the third endoscopy was performed after a mean of 10 months after eradication. Inflammation was graded according to the updated Sydney system. Interleukin (IL)1beta, IL8, IL12A, IL18, TNFalpha, IFNgamma, IL4, IL6 and IL10 expression levels were analysed by real-time RT-PCR. Mixed mononuclear and neutrophil infiltrates were seen at entry and after ulcer healing. After eradication, low-grade mononuclear infiltrates were found. The cytokine expression levels after ulcer healing (H. pylori positive gastritis) were not significantly different from the levels at entry (ulcer). After eradication, attenuation of the Th1 cytokines except for TNFalpha and a persisting increase of IL4 levels were observed, whereas the IL10 expression was markedly reduced. The present data did not indicate a specific ulcer promoting cytokine gene regulation profile. However, after eradication a chronic low-grade inflammation was seen with reduced Th1, prolonged Th2 and disappearance of the T-regulatory response.

Novel interleukin-4 and interleukin-1 receptor antagonist gene variations associated with non-cardia gastric cancer in Japan: comprehensive analysis of 207 polymorphisms of 11 cytokine genes

BACKGROUND AND AIM

Helicobacter pylori (H. pylori)-induced chronic atrophic gastritis is a high-risk factor for gastric cancer. Immune responses to H. pylori are involved in gastric mucosal inflammation, and might affect clinical outcome, including the development of gastric cancer. The present study examines the significance of gene polymorphisms of various cytokines in the development of gastric cancer following H. pylori infection.

METHODS

One hundred Japanese non-cardia gastric cancer patients and 93 dyspeptic patients as controls were enrolled in the study (age range 50-75 years). All patients were positive for H. pylori. Genomic DNA was extracted from peripheral whole blood leukocytes, and we comprehensively analyzed 207 single nucleotide polymorphisms (SNP) in 11 cytokine genes; interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist (RN), IL-4, IL-4R, IL-8, IL-10, IL-12, TNF-alpha, TNF-beta, and IFN-gamma, using either invader assay (163 SNP), direct sequencing (22 SNP), or PCR-restriction fragment length polymorphism (22 SNP).

RESULTS

Among the 207 SNP examined, the IL-4 gene diplotypes (984 and 2983 AA/GA) had a significant negative association with gastric cancer development (odds ratio =0.3, 95% confidence interval =0.1-0.9). When we adopted the dyspeptic patients over 66 years of age as the controls, the IL-1RN gene diplotypes (-1102 and 6110 CG/GA) also had a significant negative association (odds ratio =0.2, 95% confidence interval =0.1-0.7).

CONCLUSION

A comprehensive analysis of 207 SNP of 11 cytokine genes revealed that variations in IL-4 and IL-1RN genes are negatively associated with the risk of developing gastric cancer following H. pylori infection. Distinct host cytokine responses in the gastric mucosa might have a role in H. pylori-induced carcinogenesis.