Background: Epidemiological studies have suggested an association between Helicobacter pylori ( H pylori ) infection and atherosclerosis through undefined mechanisms. Endothelial dysfunction is critical to the development of atherosclerosis and related cardiovascular diseases. The present study was designed to test the hypothesis that H pylori infection impaires endothelial function through exosome‐mediated mechanisms. Methods and Results: Young male and female patients (18‐35 years old) with and without H pylori infection were recruited to minimize the chance of potential risk factors for endothelial dysfunction for the study. Endothelium‐dependent flow‐mediated vasodilatation of the brachial artery was evaluated in the patients and control subjects. Mouse infection models with CagA ⁺ H pylori from a gastric ulcer patient were created to determine if H pylori infection‐induced endothelial dysfunction could be reproduced in animal models. H pylori infection significantly decreased endothelium‐dependent flow‐mediated vasodilatation in young patients and significantly attenuated acetylcholine‐induced endothelium‐dependent aortic relaxation without change in nitroglycerin‐induced endothelium‐independent vascular relaxation in mice. H pylori eradication significantly improved endothelium‐dependent vasodilation in both patients and mice with H pylori infection. Exosomes from conditioned media of human gastric epithelial cells cultured with CagA ⁺ H pylori or serum exosomes from patients and mice with H pylori infection significantly decreased endothelial functions with decreased migration, tube formation, and proliferation in vitro. Inhibition of exosome secretion with GW 4869 effectively preserved endothelial function in mice with H pylori infection. Conclusions: H pylori infection impaired endothelial function in patients and mice through exosome‐medicated mechanisms. The findings indicated that H pylori infection might be a novel risk factor for cardiovascular diseases.

Helicobacter pylori (H. pylori) recurrence remains a significant public health concern. The study aimed to assess H. pylori reinfection rate and identify its risk factors in China. This prospective open cohort, observational study was performed at 18 hospitals across 15 provinces in China. Consecutive patients who received the successful initial eradication during 1 January 2012 and 31 December 2018 were eligible for enrolment. H. pylori recurrence was defined as reinfection that occurred at more than the 12-month interval after successful initial eradication. Surveyed risk factors that might be associated with reinfection were preliminarily estimated by log-rank test and further determined by Cox regression model to calculate the hazard ratio (HR) and 95% confidence interval (CI). A total of 5193 subjects enrolled in the study. The follow-up intervals varied from 6 to 84 months with a general follow-up rate of 67.9%. Annual reinfection rate was 1.5% (95% CI: 1.2–1.8) per person-year. H. pylori reinfection was independently associated with the following five risk factors: minority groups (HR = 4.7, 95% CI: 1.6–13.9), the education at lower levels (HR = 1.7, 95% CI: 1.1–2.6), a family history of gastric cancer (HR = 9.9, 95% CI: 6.6–14.7), and the residence located in Western China (HR = 5.5, 95% CI: 2.6–11.5) following by in Central China (HR = 4.9, 95% CI: 3–8.1) (all P < 0.05). Reinfection rate of H. pylori in China is relatively low. Patients with specific properties of ethnic groups, education level, family history, or residence location appear to be at higher risk for reinfection.

H. pylori induces a complicated local and systematic immune response and contributes to the carcinogenesis of gastric cancer. A primary type 1 immune response is evoked by H. pylori since its occurrence. However, it is not unusual that an inhibitory immunity is dominant in H. pylori-associated diseases, which are promoted by the formation of immunosuppressive microenvironment. But whether group 2 innate lymphoid cells (ILC2s) plays a critical role in H. pylori-induced skewed type 2 immunity is still unclear. In the present study, firstly, we confirmed that type 1 immunity was inhibited and type 2 immunity were undisturbed or promoted after H. pylori infection in vitro and in vivo. Secondly, GATA-3 was firstly found to be increased in the interstitial lymphocytes from H. pylori-associated gastric cancer, among them, Lin−GATA-3⁺ cells and Lin⁺GATA-3⁺ cells were also found to be enhanced, which indicated an important role for ILC2s in H. pylori infection. More importantly, ILC2s were found to be increased after H. pylori infection in clinical patients and animal models. In conclusion, our results indicated that ILC2-mediated innate immune response might play a potential role in dominant type 2 phenotype and immunosuppressive microenvironment in H. pylori infection.

Background: The chronic infection with Helicobacter pylori (H. pylori), especially cytotoxin-associated gene A-positive (CagA⁺) strains, has been associated with various extragastric disorders. Evaluating the potential impacts of virulence factor CagA on intestine may provide a better understanding of H. pylori pathogenesis such as colitis. The intestinal mucosal barrier is essential for maintaining its integrity and functions. However, how persistent CagA⁺H. pylori colonization influences barrier disruption and thereby affects chronic colitis is not fully understood. Results: Chronic colitis models of CagA⁺H. pylori-colonized mice treated with 2% Dextran sulphate sodium (DSS) were established to assess the disease activity and pertinent expression of tight junction proteins closely related to mucosal integrity. The aggravating effect of CagA⁺H. pylori infection on DSS-induced chronic colitis was confirmed in mouse models. In addition, augmented Claudin-2 expression was detected in CagA⁺H. pylori infection conditions and selected for mechanistic analysis. Next, GES-1 human gastric epithelial cells were cultured with CagA⁺H. pylori or a recombinant CagA protein, and exosomes isolated from conditioned media were then identified. We assessed the Claudin-2 levels after exposure to CagA⁺ exosomes, CagA⁻ exosomes, and IFN-γ incubation, revealing that CagA⁺H. pylori compromised the colonic mucosal barrier and facilitated IFN-γ-induced intestinal epithelial destruction through CagA-containing exosome-mediated mechanisms. Specifically, CagA upregulated Claudin-2 expression at the transcriptional level via a CDX2-dependent mechanism to slow the restoration of wounded mucosa in colitis in vitro. Conclusions: These data suggest that exosomes containing CagA facilitate CDX2-dependent Claudin-2 maintenance. The exosome-dependent mechanisms of CagA⁺H. pylori infection are indispensable for damaging the mucosal barrier integrity in chronic colitis, which may provide a new idea for inflammatory bowel disease (IBD) treatment.