Role of cyclooxygenase-2 functional gene polymorphisms in Helicobacter pylori induced gastritis and gastric atrophy

Linking dysbiosis to precancerous stomach through inflammation: Deeper than and beyond imaging

Upper gastrointestinal endoscopy is considered the gold standard for gastric lesions detection and surveillance, but it is still associated with a non-negligible rate of missing conditions. In the Era of Personalized Medicine, biomarkers could be the key to overcome missed lesions or to better predict recurrence, pushing the frontier of endoscopy to functional endoscopy. In the last decade, microbiota in gastric cancer has been extensively explored, with gastric carcinogenesis being associated with progressive dysbiosis. Helicobacter pylori infection has been considered the main causative agent of gastritis due to its interference in disrupting the acidic environment of the stomach through inflammatory mediators. Thus, does inflammation bridge the gap between gastric dysbiosis and the gastric carcinogenesis cascade and could the microbiota-inflammation axis-derived biomarkers be the answer to the unmet challenge of functional upper endoscopy? To address this question, in this review, the available evidence on the role of gastric dysbiosis and chronic inflammation in precancerous conditions of the stomach is summarized, particularly targeting the nuclear factor-κB (NF-κB), toll-like receptors (TLRs) and cyclooxygenase-2 (COX-2) pathways. Additionally, the potential of liquid biopsies as a non-invasive source and the clinical utility of studied biomarkers is also explored. Overall, and although most studies offer a mechanistic perspective linking a strong proinflammatory Th1 cell response associated with, but not limited to, chronic infection with Helicobacter pylori, promising data recently published highlights not only the diagnostic value of microbial biomarkers but also the potential of gastric juice as a liquid biopsy pushing forward the concept of functional endoscopy and personalized care in gastric cancer early diagnosis and surveillance.

Determination of gastric atrophy with artificial intelligence compared to the assessments of the modified Kyoto and OLGA classifications

BACKGROUND AND AIM

Gastric atrophy is a precancerous lesion. We aimed to clarify whether gastric atrophy determined by artificial intelligence (AI) correlates with the diagnosis made by expert endoscopists using several endoscopic classifications, the Operative Link on Gastritis Assessment (OLGA) classification based on histological findings, and genotypes associated with gastric atrophy and cancer.

METHODS

Two hundred seventy Helicobacter pylori-positive outpatients were enrolled. All patients' endoscopy data were retrospectively evaluated based on the Kimura-Takemoto, modified Kyoto, and OLGA classifications. The AI-trained neural network generated a continuous number between 0 and 1 for gastric atrophy. Nucleotide variance of some candidate genes was confirmed or selectively assessed for a variety of genotypes, including the COX-21195, IL-1β 511, and mPGES-1 genotypes.

RESULTS

There were significant correlations between determinations of gastric atrophy by AI and by expert endoscopists using not only the Kimura-Takemoto classification (P < 0.001), but also the modified Kyoto classification (P = 0.046 and P < 0.001 for the two criteria). Moreover, there was a significant correlation with the OLGA classification (P = 0.009). Nucleotide variance of the COX-2, IL-1β, and mPGES-1genes was not significantly associated with gastric atrophy determined by AI. The area under the curve values of the combinations of AI and the modified Kyoto classification (0.746) and AI and the OLGA classification (0.675) were higher than in AI alone (0.665).

CONCLUSION

Combinations of AI and the modified Kyoto classification or of AI and the OLGA classification could be useful tools for evaluating gastric atrophy in patients with H. pylori infection as the risk of gastric cancer.

Interaction of Cyclooxygenase-2 with Helicobacter pylori Induces Gastric Chronic Nonresolving Inflammation and the Formation of Syndrome of Internal Block of Static Blood in Helicobacter pylori-Related Gastric Diseases

Cyclooxygenase-2 (COX-2) is an inducible enzyme stimulated by various inflammatory factors (IFs). Chronic gastritis is a classic model of “inflammation-cancer transformation” and Helicobacter pylori-related gastric diseases (HPGD) are specific ones of this model. Traditional Chinese Medicine (TCM) syndromes could play a predictive role in gastric histopathological evolution. To search for early warning evidence about “inflammation-cancer transformation,” this study is about to explore interaction of COX-2 with Helicobacter pylori (Hp) in HPGD with different TCM syndromes. All included subjects underwent endoscopy and biopsy. Hp infection was detected by rapid urease test and methylene blue staining. Histopathological characteristics and COX-2 expression in gastric mucosa (GM) were, respectively, observed by hematoxylin-eosin and Elivision™ plus. SPSS 18.0 and Stata 11.0 statistical software packages were used for statistical analysis. Results of immunohistochemical staining in this study showed COX-2 expression in Hp-positive patients was stronger than that in Hp-negative ones. Spearman' analysis indicated that degrees of both Hp infection and COX-2 expression were positively correlated with those of gastric inflammation and inflammatory activity. Compared with the relative normal group, both severe dysplasia group and gastric carcinoma group had more severe Hp infection and COX-2 expression. Compared with the nonsyndrome, syndrome of internal block of static blood (IBSB) had higher scores in semiquantitative analysis of COX-2 protein expression among TCM groups. Moreover, multivariate logistics regression analysis suggested that patients with Hp infection could increase the risk of IBSB. These results indicated that COX-2 interacting with Hp could play an important role in transforming gastric chronic nonresolving inflammation into carcinoma in subjects with HPGD, as well as inducing the formation of IBSB. HPGD together with IBSB could be an early warning evidence for GM with histopathological evolution from benign to malignant.

Association of IL10 gene promoter polymorphisms with risks of gastric cancer and atrophic gastritis

OBJECTIVE

To investigate the association between polymorphisms of the interleukin 10 ( IL10) gene and risk of gastric cancer (GC) and atrophic gastritis (AG).

METHODS

This study enrolled patients with GC, patients with AG and healthy control subjects. Demographic data were collected and the IL10 gene -1082A/G, -819C/T and -592A/C polymorphisms were genotyped. An enzyme-linked immunosorbent assay was performed to detect Helicobacter pylori infection.

RESULTS

The study enrolled 556 participants including 208 in the GC group, 116 in the AG group and 232 controls (CON group). In a recessive model of the IL10-819C/T polymorphism, a significantly decreased risk of GC was found compared with AG and non-cancer subjects, respectively (AG→GC: odds ratio OR 0.41; non-cancer→GC: OR 0.57). The CC genotype demonstrated a significantly increased risk of AG compared with CON. Similar significant results were detected in males and H. pylori-negative subgroups. The ACC haplotype was associated with a decreased risk of GC compared with AG. The ATC haplotype was associated with a decreased risk of AG compared with the CON group, but it was associated with an increased risk of GC compared with AG.

CONCLUSION

The IL10 gene promoter -819C/T (rs1800871) polymorphism was associated with the risk of GC and AG in a Chinese population.

Impact of Cyclooxygenase-2 1195 G-Carrier Genotype Associated with Intestinal Metaplasia and Endoscopic Findings Based on Kyoto Classification

BACKGROUND/AIMS

We aimed to clarify whether cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) genotypes were associated with certain histological findings and endoscopical appearances based on Kyoto classification.

METHODS

We enrolled 285 Helicobacter pylori-infected gastritis patients. Genotypes of COX-2 1195, COX-2 1290, mPGES-1, interleukin-1β (IL-1β) 511 and tumour necrosis factor-α (TNF-α) 308 were analyzed. Genotyping was performed by polymerase chain reaction. Endoscopic appearances and histological assessment were determined by using Kyoto classification, operative link on gastritic intestinal metaplasia assessment and the updated Sydney system.

RESULTS

There was a significant (p = 0.027) relationship between the IL-1β 511 C-carrier and histological gastric inflammation in H. pylori-infected gastritis patients. There was a significant (p = 0.009) correlation between the COX-2 1195 G-carrier genotype and histological intestinal metaplasia in the gastric antrum of H. pylori-infected gastritis patients and gastric xanthoma (p = 0.027). The COX-2 1195 G-carrier genotype was also significantly (p = 0.038) associated with the score of endoscopic intestinal metaplasia based on Kyoto classification. The mPGES-1 genotype was significantly (p = 0.002) associated with endoscopic swelling of area.

CONCLUSION

Our results suggest that in Japan, there exists a significant correlation between the COX-2 1195 G-carrier genotype and intestinal metaplasia in histological and endoscopic findings based on Kyoto classification in H. pylori-infected gastric mucosa.

Polymorphisms in COX-2 gene influence prostate cancer susceptibility in a northern Indian cohort

BACKGROUND AND AIMS

Cyclooxygenase-2 (COX-2) converts arachidonic acid to prostaglandins, which are important mediators of cell proliferation and inflammation. Evidence indicates that COX-2 plays a role in carcinogenesis and that it is overexpressed in prostate tumors. We examined whether sequence variants in the COX-2 gene were associated with prostate cancer (PCa) risk.

METHODS

In a hospital-based case/control study, 195 subjects with PCa and 250 healthy controls were investigated for the association of COX-2 -765 G>C (rs20417) and +8473 T>C (rs5275) promoter polymorphism with PCa susceptibility using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method.

RESULT

Variant allele 'C' carriers of COX-2 -765 G>C polymorphism were associated with a 1.7-fold increased risk for PCa (p = 0.016; OR = 1.74). The variant genotype CC of COX-2 +8473 T>C polymorphism was found to be significantly associated with the overall higher risk of PCa (p = 0.045; OR = 1.82). Combined genotype (TC + CC) also demonstrated a 1.5-fold significant risk with PCa (p = 0.040; OR = 1.52). The diplotype C-C was observed to be associated with a significant increase in PCa risk (Bonferroni corrected p value, Pc = 0.004; OR = 4.26). Stratification of cases based on clinical pathological grade of tumors revealed no association with PCa risk.

CONCLUSIONS

Our findings suggest COX-2 -765G>C and +8473 T>C polymorphism and diplotype C-C to be a risk factor for PCa. However, further validation in large population-based studies is needed to confirm the finding.

[Single nucleotide polymorphisms and helicobacter pylori-related gastric cancer]

Helicobacter pylori-related gastric cancer is a special-type gastric cancer determined by genetic, environmental, and life style factors. A series of single nucleotide polymorphisms (SNPs) of susceptibility genes, including inflammation-related genes, gastric acid inhibition-related genes, and immune response-related genes, could be specifically involved in the development of Helicobacter pylori-related gastric cancer that consists of three major stages: Helicobacter pylori infection, gastric atrophy development, and carcinogenesis. The aim of the present paper was to review and evaluate the most recently published evidence on the contribution of SNPs to the carcinogenesis of Helicobacter pylori-related gastric cancer in humans.

The enigma of Helicobacter pylori infection and gastric cancer

Although H. pylori has been recognized as a class I carcinogen, incongruence between infection prevalence and cancer incidence has been reported. Holcombe called attention to the high prevalence of infection in the face of low cancer rates, which he called "The African Enigma". Similar observations have now been made in other geographic areas. Gastric carcinoma should be considered an infectious disease, for which the classical epidemiologic model of causality applies. The model proposes that tissue injury inflicted by the infectious agent is modulated by its interactions with host and environmental factors. Although approximately half of the world's population is infected, only a small proportion of people develop cancer. The African enigma is a striking example of the major contrasts in cancer risk among populations with similarly high prevalence of infection. The mechanisms involved in reducing the risk of cancer in infected individuals are explored in this article, which may lead to the design of effective prevention strategies.

Transforming growth factor-B1 and matrix metalloproteinase-7 promoter variants induce risk for Helicobacter pylori-associated gastric precancerous lesions

The expression of growth factors, proteolytic enzymes, fibrogenic factors, and cytokines is altered in the Helicobacter pylori-infected gastric mucosa. Therefore, we aimed to evaluate the association of functional promoter variants of transforming growth factor (TGF)-B1 and matrix metalloproteinase (MMP)-7 genes with gastritis and gastric precancerous lesions. After upper gastrointestinal endoscopy, a total of 130 rapid urease test-positive patients with nonulcer dyspepsia were examined for H. pylori infection using modified Giemsa stain and IgG anti-CagA ELISA. All patients and 200 asymptomatic controls were genotyped for TGF-B1 (-509 C>T) and MMP-7 (-181 A>G) substitutions using PCR-RFLP. The genotype and allele frequencies of TGF-B1 and MMP-7 polymorphisms did not differ between patients and controls (p > 0.05). However, the CagA-positive patients with TGF-B1 -509 T allele had higher risk for gastric atrophy (p = 0.026, odds ratio [OR] = 2.38) and lymphoid follicle development (p = 0.028, OR = 2.29). In addition, CagA-positive patients carrying MMP-7 -181 G allele had risk for lymphoid follicle formation (p = 0.027, OR = 2.30). Thus, the present study revealed significant association of functional MMP-7 and TGF-B1 gene variants toward susceptibility to H. pylori-induced precancerous gastric lesions.