Associations of plasma IL-8 levels with Helicobacter pylori seropositivity, gastric atrophy, and IL-8 T-251A genotypes

Influence of Cytokine Genetic Polymorphisms in Helicobacter pylori-Associated Gastric Inflammation According to Sex in South Korea

Background/Aims

: The relationship between genetic polymorphisms and gastric inflammation remains unclear. This study aimed to evaluate the impact of genetic polymorphisms on Helicobacter pylori (HP)-associated gastritis according to sex.

Methods

: Two hundred thirty-two male and 404 female subjects with current HP infection were prospectively enrolled. The genotyping of IL-1B-511 C/T, IL-1RN variable number of tandem repeats, IL-6-572 G/C, IL-8-251 A/T, IL-8-781 C/T, IL-10-1082 G/A, IL-10-592 C/A, TNF-A-308 G/A, and transforming growth factor (TGF)-B-509 C/T, was determined by polymerase chain reaction-restriction fragment length polymorphism. The degree of monocyte or neutrophil infiltration, atrophic gastritis, and intestinal metaplasia was evaluated using the updated Sydney system.

Results

: Among the male subjects, moderate/severe atrophic gastritis of the corpus was higher in IL-1B-511 CC carriers than in CT and TT carriers independent of age, alcohol consumption, and HP virulence factors (26.9% vs 10.4%; adjusted hazard ratio [HR], 4.377; 95% confidence interval, 1.387 to 13.814). In females, IL-8-251 AA carriers were independently and significantly associated with moderate/severe atrophic gastritis of the corpus compared with that in AT and TT carriers (21.4% vs 6.0%, adjusted HR=3.799). In males, the IL-8-251 TT genotype was associated with moderate/severe intestinal metaplasia of the corpus compared with the AT and AA genotypes (13.4% vs 5.6%, adjusted HR=3.128), while the IL-10-592 CA and CC genotypes were associated with moderate/severe monocyte infiltration of the antrum compared with AA genotype (83.6% vs 71.8%, adjusted HR=2.227).

Conclusions

: Genetic polymorphisms in cytokines play different roles in HP-associated gastritis according to sex.

Genetic polymorphisms in interleukin-1β (rs1143634) and interleukin-8 (rs4073) are associated with survival after resection of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is a rare, understudied primary hepatic malignancy with dismal outcomes. Aiming to identify prognostically relevant single-nucleotide polymorphisms, we analyzed 11 genetic variants with a role in tumor-promoting inflammation (VEGF, EGF, EGFR, IL-1B, IL-6, CXCL8 (IL-8), IL-10, CXCR1, HIF1A and PTGS2 (COX-2) genes) and their association with disease-free (DFS) and overall survival (OS) in patients undergoing curative-intent surgery for iCCA. Genomic DNA was isolated from 112 patients (64 female, 48 male) with iCCA. Germline polymorphisms were analyzed with polymerase chain reaction-restriction fragment length polymorphism protocols. The IL-1B +3954 C/C (73/112, hazard ratio (HR) = 1.735, p = 0.012) and the IL-8 -251 T/A or A/A (53/112 and 16/112, HR = 2.001 and 1.1777, p = 0.026) genotypes were associated with shorter OS in univariable and multivariable analysis. The IL-1B +3954 polymorphism was also associated with shorter DFS (HR = 1.983, p = 0.012), but this effect was not sustained in the multivariable model. A genetic risk model of 0, 1 and 2 unfavorable alleles was established and confirmed in multivariable analysis. This study supports the prognostic role of the IL-1B C+3954T and the IL-8 T-251A variant as outcome markers in iCCA patients, identifying patient subgroups at higher risk for dismal clinical outcomes.

Old and New Aspects of H. pylori-Associated Inflammation and Gastric Cancer

H. pylori is involved in the development of 80% of gastric cancers and 5.5% of all malignant conditions worldwide. Its persistence within the host’s stomach causes chronic inflammation, which is a well-known hallmark of carcinogenesis. A wide range of cytokines was reported to be involved in the initiation and long-term persistence of this local and systemic inflammation. IL-8 was among the first cytokines described to be increased in patients with H. pylori infection. Although, this cytokine was initially identified to exert a chemoattracting effect that represents a trigger for the activation of inflammatory cells within H.-pylori-infected mucosa, more recent studies failed in encountering any association between IL-8 and H. pylori infection. IL-6 is a multifunctional, pleiotropic and multipotent cytokine involved in mediating the interaction between innate and adaptive immunity with a dichotomous role acting as both a proinflammatory and an anti-inflammatory cytokine depending on the signaling pathway. IL-1α functions as a promoter of angiogenesis and vascular endothelial cell proliferation in gastric carcinoma since it is closely related to H.-pylori-induced inflammation in children. IL-1β is an essential trigger and enhancer of inflammation. The association between a low IL-1β level and an increased TNF-α level might be considered a risk factor for peptic ulcer disease in the setting of H. pylori infection. IL-10 downregulates both cytotoxic inflammatory responses and cell-mediated immune responses. H. pylori uses the immunosuppressive role of IL-10 to favor its escape from the host’s immune system. TGFβ is a continuous inflammatory mediator that promotes the adherence of H. pylori to the host’s cells and their subsequent colonization. The role of H.-pylori-induced inflammatory responses in the onset of gastric carcinogenesis seems to represent the missing puzzle piece for designing effective preventive and therapeutic strategies in patients with H.-pylori-associated gastric cancer.

40 Years of Helicobacter pylori: A Revolution in Biomedical Thought

Background: Various microorganisms such as bacteria, virus, and fungi can infect humans and cause not just a simple infection but septic conditions, organ dysfunction, and precancerous conditions or cancer involving various organ systems. After the discovery of the microscope, it was easier to discover and study such microorganisms, as in the case of Helicobacter pylori, a pathogen that was seen in the distant era of the nineteenth century but without being recognized as such. It took 100 years to later discover the pathogenesis and the cancer that this bacterium can cause. Since it was discovered, until today, there has been a continuous search for the understanding of its pathogenetic mechanisms, and the therapeutic approach is continuously updated. Methods: We investigated how diagnosis and therapy were dealt with in the past and how researchers sought to understand, exactly, the pathogenetic biomolecular mechanisms of H. pylori, from the genesis of the infection to the current knowledge, with an analysis of carcinogenic mechanisms in the stomach. We have examined the scientific evolution of the knowledge of the disease over these 40 years in the gastroenterological and pharmacological fields. This was possible through a search in the databases of Medline, the WHO website, the Centers for Disease Control and Prevention (CDC) website, PubMed, and Web of Science to analyze the earlier and the latest data regarding H. pylori. Results: With the scientific discoveries over time, thanks to an increasing number of progressions in scientific research in the analysis of the gastric mucosa, the role of Helicobacter pylori in peptic ulcer, carcinogenesis, and in some forms of gastric lymphoma was revealed. Furthermore, over the years, the biomolecular mechanism involvement in some diseases has also been noted (such as cardiovascular ones), which could affect patients positive for H. pylori. Conclusions: Thanks to scientific and technological advances, the role of the bacterium H. pylori in carcinogenesis has been discovered and demonstrated, and new prospective research is currently attempting to investigate the role of other factors in the stomach and other organs. Cancer from H. pylori infection had a high incidence rate compared to various types of cancer, but in recent years, it is improving thanks to the techniques developed in the detection of the bacterium and the evolution of therapies. Thus, although it has become an increasingly treatable disease, there is still continuous ongoing research in the field of treatment for resistance and pharma compliance. Furthermore, in this field, probiotic therapy is considered a valid adjuvant.

Cot kinase plays a critical role in Helicobacter pylori-induced IL-8 expression

Helicobacter pylori is a major pathogen causing various gastric diseases including gastric cancer. Infection of H. pylori induces pro-inflammatory cytokine IL-8 expression in gastric epithelial cells in the initial inflammatory process. It has been known that H. pylori can modulate Ras-Raf-Mek-Erk signal pathway for IL-8 induction. Recently, it has been shown that another signal molecule, cancer Osaka thyroid oncogene/tumor progression locus 2 (Cot/Tpl2) kinase, activates Mek and Erk and plays a role in the Erk pathway, similar to MAP3K signal molecule Raf kinase. Therefore, the objective of this study was to determine whether Cot kinase might be involved in IL-8 induction caused by H. pylori infection. AGS gastric epithelial cells were infected by H. pylori strain G27 or its isogenic mutants lacking cagA or type IV secretion system followed by treatment with Cot kinase inhibitor (KI) or siRNA specific for Cot kinase. Activation of Erk was assessed by Western blot analysis and expression of IL-8 was measured by ELISA. Treatment with Cot KI reduced both transient and sustained Erk activation. It also reduced early and late IL-8 secretion in the gastric epithelial cell line. Furthermore, siRNA knockdown of Cot inhibited early and late IL-8 secretion induced by H. pylori infection. Taken together, these results suggest that Cot kinase might play a critical role in H. pylori type IV secretion apparatus-dependent early IL-8 secretion and CagA-dependent late IL-8 secretion as an alternative signaling molecule in the Erk pathway.

Polymorphisms of the IL-6, IL-8 and IL-10 genes and the risk of gastric pathology in patients infected with Helicobacter pylori

BACKGROUND/PURPOSE

Helicobacter pylori-induced gastric mucosal inflammation is mediated by proinflammatory and anti-inflammatory cytokines. Polymorphisms in genes that code cytokines influence cytokine secretion levels and appear to contribute to the risk of gastric diseases. In this sense, we performed this study to identify the polymorphisms in the IL-6, IL-8, and IL-10 genes and their associations with H. pylori infection and gastric pathologies.

METHODS

Gastric biopsy samples of 151 patients infected with H. pylori and 76 uninfected individuals were used. Helicobacter pylori infection was diagnosed by histological examination and the detection of the ureA and glmM genes. The polymorphisms in the IL-6 (at position -174), IL-8 (at position -251), and IL-10 (at position -819) were detected by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Among the genetic polymorphisms studied, we observed that only the presence of the A allele at position -251 of the IL-8 gene was significantly associated with H. pylori infection. In addition, patient carriers of the A/A genotype at position -251 of the IL-8 gene and carriers of the T allele at position -819 of the IL-10 gene had an increased risk of peptic ulcer disease in the presence of H. pylori infection. We did not find a correlation between polymorphisms in the IL-6, IL-8, and IL-10 genes and a higher risk of gastric carcinoma.

CONCLUSION

We demonstrated that polymorphisms in the IL-8 gene was significantly associated with H. pylori infection. Furthermore, polymorphisms in the IL-8 and IL-10 genes were associated with an enhanced risk of peptic ulcer disease in H. pylori-positive patients.

Association between Helicobacter pylori genotypes and severity of chronic gastritis, peptic ulcer disease and gastric mucosal interleukin-8 levels: Evidence from a study in the Middle East

Background

The varied clinical presentations of Helicobacter pylori (H. pylori) infection are most likely due to differences in the virulence of individual strains, which determines its ability to induce production of interleukin-8 (IL-8) in the gastric mucosa. The aim of this study was to examine association between cagA, vacA-s1 and vacA-s2 genotypes of H. pylori and severity of chronic gastritis and presence of peptic ulcer disease (PUD), and to correlate these with IL-8 levels in the gastric mucosa.

Methods

Gastric mucosal biopsies were obtained from patients during esophagogastroduodenoscopy. The severity of chronic gastritis was documented using the updated Sydney system. H. pylori cagA and vacA genotypes were detected by PCR. The IL-8 levels in the gastric mucosa were measured by ELISA.

Results

H. pylori cagA and/or vacA genotypes were detected in 99 patients (mean age 38.4±12.9; 72 males), of whom 52.5% were positive for cagA, 44.4% for vacA-s1 and 39.4% for vacA-s2; and 70.7% patients had PUD. The severity of inflammation in gastric mucosa was increased with vacA-s1 (p=0.017) and decreased with vacA-s2 (p=0.025), while cagA had no association. The degree of neutrophil activity was not associated with either cagA or vacA-s1, while vacA-s2 was significantly associated with decreased neutrophil activity (p=0.027). PUD was significantly increased in patients with cagA (p=0.002) and vacA-s1 (p=0.031), and decreased in those with vacA-s2 (p=0.011). The level of IL-8 was significantly increased in patients with cagA (p=0.011) and vacA-s1 (p=0.024), and lower with vacA-s2 (p=0.004). Higher levels of IL-8 were also found in patients with a more severe chronic inflammation (p=0.001), neutrophil activity (p=0.007) and those with PUD (p=0.001).

Conclusions

Presence of vacA-s1 genotype of H. pylori is associated with more severe chronic inflammation and higher levels of IL-8 in the gastric mucosa, as well as higher frequency of PUD. Patients with vacA-s2 have less severe gastritis, lower levels of IL-8, and lower rates of PUD. The presence of cagA genotype is not associated with the severity of gastritis or IL-8 induction in the gastric mucosa. The association of cagA with PUD may be a reflection of its presence with vacA-s1 genotype.

Genetic traits for the persistence of Helicobacter pylori infection

Helicobacter pylori infection elevates the risk of gastric diseases, including peptic ulcer and gastric cancer. Persistent infection is the first step to induce H. pylori-induced multistage diseases. Although the roles of genetic traits on persistent infection have not yet been elucidated, some individuals escape from persistent infection. Possible favorable conditions for H. pylori seem to be low acid secretion, reduced innate immune responses, and easier binding to gastric epithelial cells. IL-1β and TNF-α inhibit acid secretion. The genetic polymorphisms associated with both molecules have the potential to be the genetic traits underlying persistent infection. Functional polymorphisms associated with innate immune responses could also be involved with the genetic traits, but no polymorphisms with consistent associations have been identified so far. The polymorphisms associated with molecules for adhesion to epithelial cells are candidates of genetic traits, but more research is needed.