Is there an antigenic mimicry between arteriosclerotic lesions and H. pylori antigens?

Positive Association Between Helicobacter pylori Infection and Metabolic Syndrome in a Korean Population: A Multicenter Nationwide Study

BACKGROUND AND AIM

Helicobacter pylori (H. pylori) infection causes extra-gastrointestinal as well as gastric diseases. This analytical cross-sectional study was performed to investigate the association between H. pylori infection and metabolic syndrome in a Korean population.

METHODS

Anthropometric and metabolic data, as well as anti-H. pylori IgG antibodies, were measured in 21,106 subjects who participated in a health checkup between January 2016 and June 2017. The classification of metabolic syndrome followed the revised National Cholesterol Education Program criteria.

RESULTS

After excluding subjects with a history of H. pylori eradication therapy, or gastric symptoms, the seropositivity of H. pylori was 43.2% in 15,195 subjects. H. pylori-positive participants had significantly higher body mass index (BMI), waist circumference, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and lower high-density lipoprotein (HDL-C) than did seronegative participants (P < 0.05). After adjusting for confounders, high TC, low HDL-C, and high LDL-C were associated with H. pylori seropositivity. Finally, the prevalence of metabolic syndrome was higher in H. pylori-seropositive subjects than in negative ones (27.2% vs. 21.0%, P < 0.05), and H. pylori seropositivity increased the likelihood of metabolic syndrome (OR 1.19, 95% CI 1.09-1.31, P < 0.001) after adjusting for sex, age, BMI, smoking, residence, household income, and education level. However, the association between H. pylori seropositivity and metabolic syndrome disappeared in those ≥ 65 years old.

CONCLUSIONS

H. pylori infection plays an independent role in the pathogenesis of metabolic syndrome in Koreans under 65 years old.

Eradication of Helicobacter pylori infection improves blood pressure values in patients affected by hypertension

BACKGROUND

Arterial hypertension is a risk factor for atherosclerosis of whose pathogenesis is unknown. Growing evidence underscores the causative role of endothelial dysfunction. A possible association between Helicobacter pylori infection and cardiovascular and autoimmune disorders has been found. The release of cytotoxic substances either of bacterial origin or produced by the host may represent mediators of these systemic sequelae. The aim of our study was to determine the prevalence of H. pylori infection in hypertensive patients and the effects of H. pylori eradication on blood pressure and on digestive symptoms.

MATERIALS AND METHODS

Seventy-two hypertensive patients (34 male and 38 female; mean age 53 +/- 12 years) and 70 normotensive controls (35 male and 35 female; mean age 52 +/- 10 years) were enrolled. All patients were subjected to a first ambulatory blood pressure monitoring (ABPM) at enrollment, a 13C urea breath test and a test for IgG-CagA antibodies, and completed the validated dyspepsia questionnaire. H. pylori-positive patients were treated with triple therapy (amoxicillin, clarithromycin and ranitidine bismute citrate) for 7 days. Control of eradication was assessed by 13C urea breath test, and all patients underwent a second ABPM 6 months after enrollment.

RESULTS

H. pylori infection was 55% in hypertensive patients, with 90% CagA positivity, and 50% in controls, with 60% CagA positivity. At the first ABPM, blood pressure values were similar in H. pylori-positive and -negative individuals; positive patients showed a significant increase in pyrosis and epigastric pain compared to negative patients. H. pylori was eradicated in 80% of patients and in 85% of controls. At the second ABPM, we found a statistically significant decrease in 24-hour mean blood pressure values when compared to the first ABPM only in the eradicated hypertensive group.

CONCLUSIONS

Our study demonstrated a significant decrease in blood pressure values, in particular in diastolic blood pressure values, after H. pylori eradication in hypertensive patients. A high prevalence of CagA positivity was found. The association between cardiovascular disease and H. pylori infection seems pronounced only in CagA-positive patients. The possible links between hypertensive disease and H. pylori infection may involve the activation of the cytokine cascade with the release of vasoactive substances from the primary site of infection, or molecular mimicry between the CagA antigens of H. pylori and some peptides expressed by endothelial cells and smooth muscle cells.

Cross-reactivity of anti-CagA antibodies with vascular wall antigens: possible pathogenic link between Helicobacter pylori infection and atherosclerosis

BACKGROUND

Helicobacter pylori-CagA positive strains have been shown to be associated with atherosclerosis. However, the pathogenesis is still undetermined. The aim of this study was to determine whether anti-CagA antibodies cross-react with antigens of normal and atherosclerotic arteries.

METHODS AND RESULTS

Eight umbilical cord sections, 14 atherosclerotic artery sections, and 10 gastrointestinal tract sections were examined by immunohistochemistry using polyclonal anti-CagA antibodies. Five atherosclerotic and 3 normal artery samples were also lysed in ice-cold lysis buffer containing protease inhibitors and were immunoprecipitated using the same antibodies. Anti-CagA antibodies reacted with cytoplasm and nuclei of smooth muscle cells in umbilical cord and atherosclerotic vessel sections, cytoplasm of fibroblasts-like cells in intimal atherosclerotic plaques, and the cell membranes of endothelial cells. Anti-CagA antibodies also specifically immunoprecipitated 2 high molecular weight antigens of 160 and 180 kDa from both normal and atherosclerotic artery lysates.

CONCLUSIONS

Anti-CagA antibodies cross-react with antigens of both normal and atherosclerotic blood vessels. We speculate that the binding of anti-CagA antibodies to those antigens in injured arteries could influence the progression of atherosclerosis in CagA-positive H pylori-infected patients.