Role of Helicobacter pylori and interleukin 6 -174 gene polymorphism in dyslipidemia: a case-control study.

OBJECTIVE: To assess the role of Helicobacter pylori infection and interleukin 6 polymorphism -174 (rs1800795) in dyslipidemia. DESIGN: Case-control study comparing serum lipids between H. pylori positive and negative patients and controlling for IL-6 -174 polymorphism, age, sex and smoking. SETTING: 3 hospitals performing outpatient endoscopies in the city of Oulu, Finland. PARTICIPANTS: 199 adult patients with dyspepsia symptoms fulfilling Rome criteria originating from ethnically Finnish population. Patients with an immunosuppressive disorder or malignant disease, treated H. pylori infection, immunosuppressive or anticoagulant medication, previous gastric surgery or ongoing antibiotic treatment were excluded. PRIMARY OUTCOME MEASURES: Association of H. pylori infection and serum lipid concentrations in the whole group or in genotype-based subgroups. The associations between peptic ulcer, gastric mucosal inflammation and serum lipid concentrations were assessed as secondary outcomes. RESULTS: The median high-density lipoprotein (HDL) serum concentration was significantly lower in the H. pylori positive group (0.81 mmol/L) than in the negative group (0.95 mmol/L; p<0.001). In the genotype subgroup analyses, a similar association between H. pylori infection and HDL serum levels was seen within the IL-6 -174 CC genotype group (HDL 0.72 vs 1.06 mmol/L, respectively; p<0.001), but no significant associations were seen in the GC or GG genotype groups. Additionally, patients with peptic ulcer demonstrated lower HDL levels (0.75 mmol/L) than H. pylori positive patients without ulcer (0.86 mmol/L; p=0.010). CONCLUSIONS: H. pylori infection associated significantly with low serum levels of HDL in the IL-6 -174 CC genotype patients but not in the other genotypes. This suggests that the association between H. pylori infection and serum HDL could be transmitted through IL-6. We suggest that the role of IL-6 genotype should also be studied in relation to other associations between gastrointestinal microbiome and cardiovascular risk factors.

Toll-Like Receptor 4 Wild Type Homozygozity of Polymorphisms +896 and +1196 Is Associated with High Gastrin Serum Levels and Peptic Ulcer Risk.

Toll-like receptor 4 is a part of the innate immune system and recognizes Helicobacter pylori lipopolysaccharide. The goal of this study was to analyze the role of Toll-like receptor 4 polymorphisms +896 (rs4986790) and +1196 (rs4986791) in the pathogenesis of Helicobacter pylori related gastroduodenal diseases in relation to gastric secretion and inflammation. Toll-like receptor 4 polymorphisms, serum gastrin-17 and pepsinogen I and II concentrations were determined, and gastroscopies with histopathological analyses were performed to 216 dyspeptic patients. As genotype controls, 179 controls and 61 gastric cancer patients were studied. In our study, the Toll-like receptor 4 +896 and +1196 polymorphisms were in total linkage disequilibrium. The homozygous wild types displayed higher gastrin-17 serum concentrations than the mutants (p = 0.001) and this effect was independent of Helicobacter pylori. The homozygous wild types also displayed an increased risk for peptic ulcers (OR: 4.390). Toll-like receptor 4 genotypes did not show any association with Helicobacter pylori positivity or the features of gastric inflammation. Toll-like receptor 4 expression was seen in gastrin and somatostatin expressing cells of antral mucosa by immunohistochemistry. Our results suggest a role for Toll-like receptor 4 in gastric acid regulation and that the Toll-like receptor 4 +896 and +1196 wild type homozygozity increases peptic ulcer risk via gastrin secretion.

Interleukin 6 gene polymorphism -174 is associated with the diffuse type gastric carcinoma.

The aim of this study was to assess the significance of the interleukin 6 gene polymorphism -174 in gastric cancer risk. The interleukin 6 -174 G/C (rs1800795) gene polymorphisms was analyzed in gastric cancer, peptic ulcer, and nonulcer dyspepsia patients and in healthy control subjects and the data were correlated with the histopathological features of the patients' biopsies. The interleukin 6 -174 GG and GC genotypes have been previously associated with high interleukin 6 serum levels. We discovered that the interleukin 6 -174 GG and GC genotypes are associated with an increased risk of the diffuse histologic subtype of gastric carcinomas (OR: 6.809, P = 0.034), but absent in the intestinal type carcinomas (OR: 1.109, P = 0.908). No significant associations with peptic ulcer, gastric atrophy, or intestinal metaplasia were seen. Our results demonstrate that the interleukin 6 -174 GG and GC genotypes increase the risk of the diffuse type gastric carcinoma, but not the intestinal type gastric carcinoma or its precursor conditions, including atrophy or intestinal metaplasia. Thus, interleukin 6 seems to be an important carcinogenetic factor in the diffuse type gastric adenocarcinoma and its carcinogenetic effect could be noninflammatory.

Cytokine gene polymorphism in microscopic colitis association with the IL-6-174 GG genotype.

OBJECTIVES: Microscopic colitis (MC) is a chronic inflammatory disease with unknown pathogenesis. Very little is known about polymorphisms in the cytokine genes in MC. We have investigated the occurrence of well-characterized polymorphisms of interleukins (IL-6, IL-1ß, IL-1 receptor antagonist, IL-10) and CD14 in MC. We also determined the serum IL-6 levels. METHODS: We genotyped 81 patients with MC and 178 controls for polymorphisms of IL-6-174, IL-1ß-511, IL-1ß-3953, IL-1 receptor antagonist, IL-10-1082 and CD14-159. Serum concentration of IL-6 was measured in 72 patients. RESULTS: Genotype GG of IL-6-174 was more prevalent in MC compared with the controls (P=0.030; odds ratio: 1.941; confidence interval: 1.078-3.495), and the frequency of allele G of IL-6-174 was higher in MC (0.55 vs. 0.47; P=0.036; odds ratio: 1.514; confidence interval: 1.041-2.203). However, after correction for multiple comparisons, the difference became nonsignificant. IL-6 genotype and the serum IL-6 concentration showed no association. The concentration of IL-6 was higher in patients with collagenous colitis than in those with lymphocytic colitis (median 1.73 vs. 1.34 pg/ml, P=0.011). No association between polymorphisms of other cytokine genes and MC was seen. CONCLUSION: The IL-6-174 gene polymorphism has a possible association with MC, as the IL-6 GG genotype was more frequent in patients with the disease. As this genotype may be linked with an enhanced IL-6 production, we speculate that this polymorphism can influence the pathogenesis of MC by evoking a proinflammatory bias in the mucosal cytokines. The enhanced concentration of IL-6 in collagenous colitis compared with lymphocytic colitis supports a difference in the pathogenetic mechanisms between the two subgroups of MC.

Human leucocyte antigen and TNFalpha polymorphism association in microscopic colitis.

OBJECTIVES: Coeliac disease (CD) is common in patients with microscopic colitis (MC). The human leucocyte antigen (HLA)-DR3-DQ2 haplotype is strongly associated with CD, and there is evidence for an association with MC. We analysed the genetic background of MC by assessing the haplotypes of HLA-DR3-DQ2 and HLA-DR4-DQ8. In addition, TNFalpha gene polymorphism (-308) associated with susceptibility to several autoimmune diseases was studied. METHODS: Eighty patients with MC including 29 with collagenous colitis (CC) and 51 with lymphocytic colitis (LC) were typed for HLA-DR3-DQ2, and HLA-DR4-DQ8 molecule encoding genes using either an allele-specific PCR, or hybridization with sequence-specific oligonucleotides. Duodenal biopsies (N=78) confirmed the diagnosis of CD in 15 (18.8%) patients. TNFalpha(308) alleles were analyzed in 78 patients with MC (27 with CC and 51 with LC). A control group of 3627 patients was used in the HLA study and 178 patients in the TNFalpha study. RESULTS: HLA-DR3-DQ2 haplotype was more frequent in patients with MC (43.8%) including both subgroups (LC, 44.8%; CC, 43.1%; P<0.001), and MC with CD (86.7%; P<0.001) and without CD (33.3%; P=0.003), compared with the controls (18.1%). Similarly, the TNF2 carrier rate was higher in MC (46.2%; P<0.001) including both CC (44.4%; P=0.031) and LC (47.1%; P=0.001), and both MC patients with CD (66.7%; P=0.001) and without CD (39.3%; P=0.019), compared with the controls (23%). CONCLUSION: Both CC and LC are associated with the HLA-DR3-DQ2 haplotype and with TNF2 allele carriage. These associations are present also in MC patients without CD. The shared predisposing HLA-DR3-DQ2 haplotype and the high prevalence of CD in patients with MC suggest an epidemiological overlap, and probably some similarities in the pathogenesis of CD and MC.

Evolution of gastritis in patients with gastric erosions.

OBJECTIVE: Gastric erosions are mainly associated with Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs), but there has been no information available on the long-term evolution of gastritis in subjects with erosions. MATERIAL AND METHODS: A series of 117 patients with gastric erosions without peptic ulcer disease and matched controls without erosions or ulcers were studied. Available subjects underwent endoscopy and biopsy 17 years later. Parietal cell antibodies were analysed at the first visit. RESULTS: Fifty-two patients and 67 controls were available for follow-up. Since H. pylori was a major determinant of gastritis, only subjects with unchanged H. pylori status were included in the evaluation of gastritis progression. At the follow-up visit, gastric erosions were present in 38% (16/42) of the patients and 11% (5/46) of the controls (p=0.005). In H. pylori-negative subjects, no evolution of histological changes was seen. In H. pylori-positive subjects, body gastritis was initially less active in the erosion group. With time, antral gastritis worsened only in the erosion group. Parietal cell antibodies were more common in the control group (23%; erosion patients 0%; p=0.01), which also showed worsening of gastritis (p=0.003) and aggravation of atrophy (p=0.002) in the body mucosa. CONCLUSIONS: Gastritis in H. pylori-positive subjects with gastric erosions shows evolution of antral predominance, body predominance including development of atrophic changes being rare. Accordingly, patients with erosions share the characteristics of gastritis of the duodenal ulcer phenotype. These findings support the importance of H. pylori and acid in the pathogenesis of gastric erosions in H. pylori-positive patients.