Prospective study of potentially virulent strains of Helicobacter pylori and coronary heart disease in middle-aged men

Preventive effect of Helicobacter pylori eradication on the coronary heart diseases depending on age and sex with a median follow-up of 51 months

BACKGROUND

The association between Helicobacter pylori (HP) infection and coronary heart disease (CHD) is controversial. This study aimed to investigate the effect of H. pylori eradication on CHD, especially in terms of age and sex.

MATERIALS AND METHODS

From May 2003 to March 2022, 4765 subjects with H. pylori infection and without CHD (median follow-up: 51 months) were prospectively enrolled. The participants were categorized into two groups: H. pylori eradication and H. pylori non-eradication. After propensity-score matching (PSM), the effect of H. pylori eradication on CHD was analyzed using Cox proportional hazards.

RESULTS

There were no significant differences in age, sex, alcohol consumption, smoking habits, history of diabetes, hypertension, and dyslipidemia, and aspirin intake between the eradication and non-eradication groups (3783 vs. 982) before and after PSM. Multivariate analysis after PSM showed that H. pylori eradication (HR: 0.489, CI: 0.314-0.761, p = .002), age (HR: 1.027, CI: 1.007-1.047, p = .007), hypertension (HR: 2.133, CI: 1.337-3.404, p = 001), dyslipidemia (HR: 1.758, CI: 1.086-2.848, p = .022), and aspirin intake (HR: 2.508, CI: 1.566-4.017, p < .001) were associated with CHD development. H. pylori eradication prevented CHD in males ≤65 years (HR: 0.133, CI: 0.039-0.455, p = .001), but not in those aged >65 years (p = .078) (p for interaction = .022). In contrast, females aged >65 years (HR: 0.260, CI: 0.110-0.615, p = .002) were protected by H. pylori eradication and not those ≤65 years (p = .485) (p for interaction = .003). This preventive effect increased more after PSM, particularly in males ≤65 years and females >65 years.

CONCLUSIONS

H. pylori eradication prevented CHD and this effect was different depending on age and sex.

Prevalence of H. pylori among patients undergoing coronary angiography (The HP-DAPT prevalence study)

Helicobacter pylori (H. pylori) screening and treatment is recommended for patients on chronic aspirin (ASA) therapy to reduce the risk of gastrointestinal bleeding. Coronary artery disease patients requiring combination antithrombotic therapy (dual antiplatelet therapy; DAPT, or dual pathway inhibition; DPI) are at an even higher risk of GI bleeding. Therefore, we aimed to evaluate the prevalence of H. pylori among patients referred for angiography and likely to receive DAPT or DPI. This single-center prospective observational study recruited patients undergoing coronary angiography and with the possibility of requiring DAPT or DPI. All included patients underwent H. pylori serology testing. Multivariable logistic regression was performed to determine predictors of seropositivity. 195 patients were included in the analysis. Mean age was 67 years, 50% had known prior CAD, and 49% underwent coronary intervention. H. pylori serology was positive in 36%. Chronic kidney disease (odds ratio [OR] 2.76; 95% confidence interval [CI] 1.24 to 6.15; p = 0.01) and chronic obstructive pulmonary disease (OR 2.52; 95% CI 1.14 to 5.55; p = 0.02) history were independent predictors of H. pylori seropositivity. Given the clinically significant prevalence of H. pylori seropositivity among patients referred for angiography, systematic screening strategies and eradication of H. pylori could significantly reduce the incidence of GI bleeding in patients requiring DAPT or DPI.

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.

Sex-Specific Risk Factors Associated with Helicobacter pylori Infection Among Individuals Undergoing Health Examinations in China

Purpose

Helicobacter pylori is one of the most common causes of peptic ulcers, gastritis, and gastric cancers. This study investigated sex-specific differences in the prevalence of H. pylori infection and its associated factors among individuals undergoing hospital-based health examinations in southern China.

Methods

This study enrolled consecutive healthy individuals who underwent regular health examinations at a hospital physical examination center between September 2020 and September 2021. Anthropometric characteristics and biochemical profiles were measured. All individuals underwent carbon-13 urea breath tests. Univariate and multivariate analyses were used to evaluate the factors associated with H. pylori infection.

Results

A total of 5035 individuals (men, 59.1%; women, 40.9%) were included in the analyses. The total rate of H. pylori infection was 35.0% (men, 35.5%; women, 34.3%). In the multivariate analysis, the risk factors identified for H. pylori infections were high fasting blood glucose levels and blood pressure ≥160 mmHg in men and older age, high body mass index, and low albumin levels in women.

Conclusion

These findings suggest that physicians must be aware of the metabolic factors associated with H. pylori infections in the Chinese population. Early detection of these factors and timely intervention are expected to reduce H. pylori infections and provide a theoretical basis for the primary prevention of several gastrointestinal diseases.

An Updated Meta-Analysis of the Relationship Between Helicobacter pylori Infection and the Risk of Coronary Heart Disease

Background

Coronary heart disease (CHD) is one of the leading causes of mortality in the world. Although the traditional risk factors for CHD have been identified, it seems that there are still many CHD cases without these factors. Previous studies have hypothesized that Helicobacter pylori (H. pylori) infection was associated with the risk of CHD.

Objective

The association between H. pylori infection and the risk of CHD was studied using a systematic evaluation and meta-analysis method.

Methods

In order to find relevant studies, four electronic databases were systematically searched until August 2021. According to the inclusion and exclusion criteria, studies were screened and data were extracted. Under the random-effects or the fixed-effects model, the odds ratio (OR) and 95% confidence interval (95% CI) were combined. All analyses were conducted using Review Manager software (RevMan 5.4).

Results

Among the included studies, 2 studies were analyzed for H. pylori stool antigen test, 2 studies were analyzed for H. pylori histological staining test, 13 studies were analyzed for the anti-CagA test, and 38 studies were analyzed for the anti-H. pylori IgG test. The pooled results revealed that positive anti-H. pylori IgG was significantly associated with an increased risk of CHD (OR, 1.58; 95% CI: 1.34–1.87). Similarly, positive anti-CagA, positive H. pylori stool antigen, and positive H. pylori histological staining were significantly associated with the development of CHD with (OR: 1.33, 95% CI: 1.16–1.53), (OR: 3.50, 95% CI: 1.60–7.66), and (OR: 1.78, 95% CI: 1.12–2.83), respectively.

Conclusion

This meta-analysis showed that H. pylori infection increased the risk of CHD. However, more studies are needed to further investigate whether early eradication of H. pylori may reduce the morbidity of CHD.

Benefits of Helicobacter pylori Eradication on Extragastric Diseases

Helicobacter pylori (H. pylori) eradication can reduce the risk of gastric diseases such as gastritis, gastric ulcer, and gastric adenocarcinoma. Since H. pylori was discovered more than 30 years ago, many studies have reported associations between H. pylori infection and extragastric diseases such as immune thrombocytopenia and iron-deficiency anemia. Thus, recent guidelines recommended H. pylori eradication in patients with those diseases. In contrast, although the role of H. pylori eradication in other extragastric diseases remains controversial, there is growing evidence of its benefit on them, especially cardiovascular (ischemic heart disease and stroke), metabolic (dyslipidemia, diabetes mellitus, and non-alcoholic fatty liver disease), neurodegenerative (Parkinson’s disease and Alzheimer’s disease), autoimmune (Graves’ disease, Hashimoto’s thyroiditis, Raynaud’s syndrome, rosacea, and chronic urticaria), and other (cap polyposis, colorectal mucosa-associated lymphoid tissue lymphoma, periodontal disease, hyperemesis gravidarum, and osteoporosis) conditions. A recent prospective randomized study reported that H. pylori eradication improved insulin resistance and dyslipidemia. These findings were consistent with the results of a recent meta-analysis. Therefore, well-designed prospective interventional studies are needed to examine the effects of H. pylori eradication on various extragastric diseases.

Low- and moderate-dose non-cancer effects of ionizing radiation in directly exposed individuals, especially circulatory and ocular diseases: a review of the epidemiology

PURPOSE

There are well-known correlations between high and moderate doses (>0.5 Gy) of ionizing radiation exposure and circulatory system damage, also between radiation and posterior subcapsular cataract. At lower dose correlations with circulatory disease are emerging in the Japanese atomic bomb survivors and in some occupationally exposed groups, and are still to some extent controversial. Heterogeneity in excess relative risks per unit dose in epidemiological studies at low (<0.1 Gy) and at low-moderate (>0.1 Gy, <0.5 Gy) doses may result from confounding and other types of bias, and effect modification by established risk factors. There is also accumulating evidence of excess cataract risks at lower dose and low dose rate in various cohorts. Other ocular endpoints, specifically glaucoma and macular degeneration have been little studied. In this paper, we review recent epidemiological findings, and also discuss some of the underlying radiobiology of these conditions. We briefly review some other types of mainly neurological nonmalignant disease in relation to radiation exposure.

CONCLUSIONS

We document statistically significant excess risk of the major types of circulatory disease, specifically ischemic heart disease and stroke, in moderate- or low-dose exposed groups, with some not altogether consistent evidence suggesting dose-response non-linearity, particularly for stroke. However, the patterns of risk reported are not straightforward. We also document evidence of excess risks at lower doses/dose-rates of posterior subcapsular and cortical cataract in the Chernobyl liquidators, US Radiologic Technologists and Russian Mayak nuclear workers, with fundamentally linear dose-response. Nuclear cataracts are less radiogenic. For other ocular endpoints, specifically glaucoma and macular degeneration there is very little evidence of effects at low doses; radiation-associated glaucoma has been documented only for doses >5 Gy, and so has the characteristics of a tissue reaction. There is some evidence of neurological detriment following low-moderate dose (∼0.1-0.2 Gy) radiation exposure in utero or in early childhood.

A meta-analysis of the association between Helicobacter pylori infection and risk of atherosclerotic cardiovascular disease

BACKGROUND

Helicobacter pylori (H pylori) infection may be a risk factor for cardiovascular disease (CVD), but the reported researches have given conflicting results.

AIMS

To investigate the association between H pylori infection and risk of atherosclerotic CVD.

MATERIALS AND METHODS

The studies were retrieved in Embase, PubMed, Web of Science (published from Jan 1, 1990, to Jan 31, 2020, language restrictions: English). All studies included used data from case-control studies and cohort studies of cardiovascular adverse events. Random effect models were used to measure pooled estimates. All data were analyzed with Stata 11.2 SE (StataCorp, College Station, TX).

RESULTS

Helicobacter pylori infection increased the risk of adverse cardiovascular events by 51% (40 studies, n = 19 691, odd ratio [OR] = 1.51, 95% confidence interval [CI]: 1.34-1.70). The effect was greater for studies that the type of CVDs was myocardial infarction (MI) and cerebrovascular disease (MI OR = 1.80, 95% CI: 1.42-2.26, cerebrovascular disease OR = 1.54, 95% CI: 1.27-1.89). Meanwhile, CagA seropositive H pylori strains were associated with a significantly increased risk of cardiovascular adverse events based on published research data (OR = 1.73, 95% CI: 1.40-2.14).

CONCLUSION

In conclusion, H pylori infection enhanced the risk of atherosclerotic cardiovascular adverse events, especially in some patients with MI and cerebrovascular disease. This study will provide guidance for the targeted prevention and treatment of CVDs. But this association need to be confirmed by more prospective studies.

Helicobacter pylori infection and severity of coronary atherosclerosis in patients with chronic coronary artery disease

AIM

Controversy exists concerning the relation between Helicobacter pylori (HP) infection and coronary artery disease (CAD). We aimed to examine the relationship between HP infection and severity of coronary atherosclerosis in patients with chronic CAD.

PATIENTS AND METHODS

A total of 150 patients (109 [73%] men; mean age 62.61±10.23 years) scheduled for coronary artery bypass grafting surgery were consecutively enrolled in the cross-sectional study. According to rapid urease test and/or gastric biopsy samples stained with hematoxylin and eosin and according to Giemsa, patients were classified as HP positive (n=87; 58%) or HP negative (n=63; 42%). Coronary angiograms were scored by quantitative assessment, using multiple angiographic scoring system: 1) vessel score (number of coronary arteries stenosed ≥50%), 2) Gensini score (assigning a severity score to each coronary stenosis according to the degree of luminal narrowing and its topographic importance) and 3) angiographic severity score (number of coronary artery segments stenosed ≥50%).

RESULTS

In comparison to HP-negative patients, HP-positive patients were more frequently hypertensive (P=0.014), had higher values of systolic (P=0.043) and diastolic (P=0.005) blood pressure and total cholesterol (P=0.013) and had lower values of high-density lipoprotein-cholesterol (HDL-C; P=0.010). There were no significant differences between the groups in the severity of coronary atherosclerosis: vessel score (P=0.152), Gensini score (P=0.870) and angiographic severity score (P=0.734).

CONCLUSION

It is likely that HP infection is not a risk factor for the severity of coronary atherosclerosis in chronic CAD patients.

Radiation and circulatory disease

Exposure to therapeutic doses of ionizing radiation is associated with damage to the heart and coronary arteries. However, only recently have studies with high-quality individual dosimetry data allowed this risk to be quantified while also adjusting for concomitant chemotherapy, and medical and lifestyle risk factors. At lower levels of exposure the evidence is less clear. In this article I review radiation-associated risks of circulatory disease in groups treated with radiotherapy for malignant and non-malignant disease, and in occupationally- or environmentally-exposed groups receiving rather lower levels of radiation dose, also for medical diagnostic purposes. Results of a meta-analysis suggest that excess relative risks per unit dose for various types of heart disease do not exhibit statistically significant (p>0.2) heterogeneity between studies. Although there are no marked discrepancies between risks derived from the high-dose therapeutic and medical diagnostic studies and from the moderate/low dose occupational and environmental studies, at least for ischemic heart disease and stroke there are indications of larger risks per unit dose for lower dose rate and fractionated exposures. Risks for stroke and other types of circulatory disease are significantly more variable (p<0.0001), possibly resulting from confounding and effect-modification by well known (but unobserved) risk factors. Adjustment for any of mean dose, dose fractionation or age at exposure results in the residual heterogeneity for cerebrovascular disease becoming non-significant. The review provides strong evidence in support of a causal association between both low and high dose radiation exposure and most types of circulatory disease.

Serum and Mucosal Cytokine Profiles in Patients with Active Helicobacter Pylori and Ischemic Heart Disease: Is There a Relationship?

This study is designed to investigate, for the first time, circulating and gastric mucosal levels of IL1-α, IL-6, IL-8 and TNF-α in patients with ischemic heart disease (IHD) and matched controls, according to the presence or absence of active Helicobacter pylori infection. Furthermore, in order to evaluate whether modified lipid profile was associated to an increased cardiovascular risk, this was determined in the same groups. Cytokine levels were measured using ELISA in 58 patients with IHD and 52 controls. Active H. pylori infection was assessed if either culture of H. pylori or rapid urease test gave a positive result. Our findings indicate increasing cytokine mucosal levels in H. pylori-positive patients compared to H. pylori-negative subjects. However, the increase was statistically significant only for IL-6 and TNF-α in the gastric mucosa of IHD patients. In H. pylori-positive controls, IL-8 mucosal levels positively correlated with both IL-1α (r = 0.98; P = 0.0003) and IL-6 (r = 0.83; P = 0.03) levels. Circulating cytokine levels were comparable in IHD and healthy subjects, regardless of H. pylori status. There were no correlations between mucosal and circulating cytokine levels. Active H. pylori infection was not associated with a modified lipid profile in either controls or IHD patients, although ApoAI levels were significantly higher in H. fly/ort'-positive controls compared to those H. pylori-negative. Taken together, the results of the present study provide evidence that active H. pylori infection may play a role as a trigger factor in the pathophysiology of IHD by inducing an inflammatory cascade concentrated on gastric mucosa.

A Meta-Analysis of the Association between Helicobacter pylori Infection and Risk of Coronary Heart Disease from Published Prospective Studies

BACKGROUND

The association between helicobacter pylori (Hp) infection and coronary heart disease (CHD) has long been debated, and the results from previous meta-analysis are varied.

AIMS

The aim for this study was to identify the association between Hp and CHD using published perspective cohort studies.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed on studies published from January, 1992 to April, 2014. All studies included used data from prospective cohort studies of CHD events or CHD deaths. Random effect models were applied in all estimations.

RESULTS

H. pylori infection increased the risk of CHD events by 11% (19 studies, n = 22,207, risk ratio (RR) = 1.11, 95% confidence interval (CI): 1.01-1.22). This effect was greater for studies that had less than 5 years' follow-up time (RR = 1.15, 95% CI: 1.00-1.32). However, this effect was not significant for studies that had follow-up times ≥10 years (n = 5100, RR = 1.04, 95% CI: 0.87-1.24). Neither Cag-A seropositive nor Cag-A seronegative strains of H. pylori were associated with a significantly increased risk of CHD events or deaths based on the current published data.

CONCLUSION

In conclusion, H. pylori infection increased the risk of CHD events, especially in a patient's early life, but this association was weaker or might be masked by other CHD risk factors in long-term observations.

Low dose radiation and circulatory diseases: a brief narrative review

Exposure to high doses of ionizing radiation is associated with damage to the heart and coronary arteries. However, only recently have studies with high-quality individual dosimetry data allowed this risk to be estimated while adjusting for concomitant chemotherapy. An association between lower dose exposures and late-occurring circulatory disease has only recently been suspected in the Japanese atomic bomb survivors and in various occupationally exposed cohorts and is still controversial. Excess relative risks per unit dose in moderate- and low-dose epidemiological studies are variable, possibly resulting from confounding and effect-modification by well known (but unobserved) risk factors. Here, we summarize the evidence for a causal association between moderate- and low-level radiation exposure (whether at high or low dose rates) and circulatory disease.

Role of Helicobacter pylori infection in pathogenesis of atherosclerosis

Though a century old hypothesis, infection as a cause for atherosclerosis is still a debatable issue. Epidemiological and clinical studies had shown a possible association but inhomogeneity in the study population and study methods along with potential confounders have yielded conflicting results. Infection triggers a chronic inflammatory state which along with other mechanisms such as dyslipidemia, hyper-homocysteinemia, hypercoagulability, impaired glucose metabolism and endothelial dysfunction, contribute in pathogenesis of atherosclerosis. Studies have shown a positive relations between Cytotoxic associated gene-A positive strains of Helicobacter pylori and vascular diseases such as coronary artery disease and stroke. Infection mediated genetic modulation is a new emerging theory in this regard. Further large scale studies on infection and atherosclerosis focusing on multiple pathogenetic mechanisms may help in refining our knowledge in this aspect.

Association between Bacterial Infection and Peripheral Vascular Disease: A Review

There are an increasing number of data showing a clinically important association between bacterial infection and peripheral artery disease (PAD). Bacteria suspected of being involved in PAD pathogenesis are: periodontal bacteria, gut microbiota, Helicobacter pylori, and Chlamydia pneumoniae. Infectious agents may be involved in the pathogenesis of atherosclerosis via activation of a systemic or local host immunological response to contamination of extravascular tissues or the vascular wall, respectively. A systemic immunological reaction may damage vascular walls in the course of autoimmunological cross-reactions between anti-pathogen antibodies and host vascular antigens (immunological mimicry), pathogen burden mechanisms (nonspecific activation of inflammatory processes in the vascular wall), and neuroendocrine-immune cross-talk. Besides activating the inflammatory pathway, bacterial infection may trigger PAD progression or exacerbation by enhancement of platelet reactivity, by a stimulatory effect on von Willebrand factor binding, factor VIII, fibrinogen, P-selectin activation, disturbances in plasma lipids, increase in oxidative stress, and resistance to insulin. Local inflammatory host reaction and induction of atherosclerotic plaque progression and/or instability result mainly from atherosclerotic plaque colonization by microorganisms. Despite these premises, the role of bacterial infection in PAD pathogenesis should still be recognized as controversial, and randomized, controlled trials are required to evaluate the outcome of periodontal or gut bacteria modification (through diet, prebiotics, and probiotics) or eradication (using antibiotics) in hard and surrogate cardiovascular endpoints.

Helicobacter pylori: Does it add to risk of coronary artery disease

Helicobacter pylori (H. pylori) is a known pathogen implicated in genesis of gastritis, peptic ulcer disease, gastric carcinoma and gastric lymphoma. Beyond the stomach, the organism has also been implicated in the causation of immune thrombocytopenia and iron deficiency anemia. Although an area of active clinical research, the role of this gram negative organism in causation of atherosclerosis and coronary artery disease (CAD) remains enigmatic. CAD is a multifactorial disease which results from the atherosclerosis involving coronary arteries. The major risk factors include age, diabetes mellitus, smoking, hypertension and dyslipidemia. The risk of CAD is believed to increase with chronic inflammation. Various organisms like Chlamydia and Helicobacter have been suspected to have a role in genesis of atherosclerosis via causation of chronic inflammation. This paper focuses on available evidence to ascertain if the role of H. pylori in CAD causation has been proven beyond doubt and if eradication may reduce the risk of CAD or improve outcomes in these patients.

Clinical significance of Helicobacter pylori infection in patients with acute coronary syndromes: an overview of current evidence

Although Helicobacter pylori (Hp) primarily colonizes gastric mucosa, it can occasionally inhabit in atherosclerotic plaques. Both forms of Hp infection may be involved in the pathogenesis of atherosclerosis via activation of a systemic or local inflammatory host reaction and induction of plaque progression and/or instability, possibly leading to coronary syndromes. The association between Hp infection and cardiovascular endpoint prevalence remains uncertain; however, it has been reported in many epidemiological investigations and may be reasonably explained by pathophysiological mechanisms. Besides the inflammatory pathway, Hp infection may trigger acute coronary syndromes by enhanced platelet reactivity and increased risk of gastrointestinal bleeding (type 2 myocardial infarction). The former seems to be predominantly related to the stimulatory effect of Hp infection on von Willebrand factor-binding and P-selectin activation, and the latter results from cytotoxic bacteria properties and aggravation of digestive tract injury related to aspirin or dual antiplatelet therapy. Despite these premises, the role of Hp infection in cardiovascular syndromes should still be recognized as controversial and requiring randomized, controlled trials to evaluate the outcome of Hp eradication in both cardiac and gastroenterological endpoints. Such need is also justified by potential bias of previous studies resulting from (1) using different diagnostic methods for identification of Hp infection, since only a small number of studies required confirmation of active Hp infection; and from (2) common lack of adjustment for important confounders such as socioeconomic status, smoking and effectiveness of eradication therapy, as well as the genetic characteristics of both the host and the bacterium.

Clinical effects of Helicobacter pylori outside the stomach

The discovery of Helicobacter pylori infection in the stomach could be considered as one of the most important events of modern gastroenterology. Understanding of the natural history of many disorders of the upper gastrointestinal tract, including chronic gastritis, peptic ulcer disease, gastric cancer and MALT lymphoma, was altered by this discovery. Interestingly, epidemiological studies have also revealed a correlation between H. pylori infection and some diseases localized outside the stomach, especially those characterized by persistent and low-grade systemic inflammation. Of note, H. pylori has an important role in iron deficiency anaemia, idiopathic thrombocytopenic purpura and vitamin B12 deficiency. Moreover, the association of this bacterial pathogen with many other diseases, including hepatobiliary, pancreatic, cardiovascular and neurodegenerative disorders is currently under investigation. In this Review, we summarize the results of the most important studies performed to date surrounding the association of H. pylori infection with extragastric diseases, as well as the strength of the evidence. We also provide information concerning bacterial-host interactions and the mechanisms implicated in the pathogenesis of each of these extragastric diseases.

Significant association between serum interleukin-6 and Helicobacter pylori antibody levels among H. pylori-positive Japanese adults

Background. Interleukin-6 (IL-6) is a multifunctional cytokine produced by many types of cells. Inflammation plays a key role in the pathogenesis of atherosclerosis that is an underlying cause of coronary heart disease (CHD). Since the 1990s, some studies have shown an association between H. pylori infection and CHD, which may be mediated by inflammation. Therefore, this study aimed to evaluate the association between serum anti-H. pylori IgG levels and serum IL-6 levels in H. pylori-infected adults. Methods. We enrolled 158 subjects who visited a clinic located in an urban area to be tested for H. pylori infection, using the ¹³C-urea breath test, and who were found to be infected and subsequently received eradication. Results. The geometric mean serum IL-6 level was 1.78 pg/mL for men, 1.57 pg/mL for women, and 1.64 pg/mL overall. Logarithms of serum IL-6 levels were positively correlated with logarithms of serum H. pylori IgG levels (r = 0.24, P = 0.002). In multiple linear regression analysis adjusting for sex and age, the serum IL-6 level was still significantly associated with the IgG level in all subjects (β = 0.18, P = 0.012). Conclusion. Higher H. pylori IgG levels were significantly associated with higher serum IL-6 levels among H. pylori-infected individuals.

Cross-sectional study: CagA-positive Helicobacter pylori infection, acute coronary artery disease and systemic levels of B-type natriuretic peptide

BACKGROUND

B-type natriuretic peptide (BNP) determination is routinely used to evaluate the severity of congestive heart failure, a possible consequence of coronary artery disease (CAD). CAD originates from vascular atherosclerotic processes and is stimulated by inflammatory events, which may also be triggered by chronic bacterial infections.

AIM

To explore the effect of Helicobacter pylori infection upon systemic BNP, tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels and linear homology between cardiac peptides and H pylori.

METHODS

A group of 103 consecutive patients with a diagnosis of non-ST elevation acute CAD (ACAD) and no other concomitant pathology was examined. BNP was measured by a commercial solid-phase sandwich immunoradiometric assay. H pylori infection, CagA serological status and circulating levels of IL-6 and TNF-α, were determined by ELISA assays. Amino acid sequence homology between human cardiac and H pylori peptides was investigated by Basic Local Alignment Search Tool (BLAST) analysis.

RESULTS

Circulating levels of BNP and IL-6, in pg/mL (interquartile difference), among infected patients with anti-CagA serum antibodies, respectively 781 (1899) and 37.7 (137.6), were significantly increased in respect to those measured in uninfected patients, respectively 325 (655) and 7.7 (23.5), (p<0.01 and p=0.025), and, with regard to BNP alone, also in patients infected by CagA negative H pylori strains, 305 (593), (p<0.01). TNF-α levels were raised in CagA positive in respect to uninfected patients. Tropomyosin and Ca2+ transporting ATPases showed strong similarities to H pylori proteins, suggesting the existence of molecular mimicry phenomena.

CONCLUSIONS

Chronic infection by H pylori expressing CagA correlates with high circulating levels of BNP and IL-6 in patients with ACAD.

A review of non-cancer effects, especially circulatory and ocular diseases

There is a well-established association between high doses (>5 Gy) of ionizing radiation exposure and damage to the heart and coronary arteries, although only recently have studies with high-quality individual dosimetry been conducted that would enable quantification of this risk adjusting for concomitant chemotherapy. The association between lower dose exposures and late occurring circulatory disease has only recently begun to emerge in the Japanese atomic bomb survivors and in various occupationally exposed cohorts and is still controversial. Excess relative risks per unit dose in moderate- and low-dose epidemiological studies are somewhat variable, possibly a result of confounding and effect modification by well-known (but unobserved) risk factors. Radiation doses of 1 Gy or more are associated with increased risk of posterior subcapsular cataract. Accumulating evidence from the Japanese atomic bomb survivors, Chernobyl liquidators, US astronauts, and various other exposed groups suggests that cortical cataracts may also be associated with ionizing radiation, although there is little evidence that nuclear cataracts are radiogenic. The dose-response appears to be linear, although modest thresholds (of no more than about 0.6 Gy) cannot be ruled out. A variety of other non-malignant effects have been observed after moderate/low-dose exposure in various groups, in particular respiratory and digestive disease and central nervous system (and in particular neuro-cognitive) damage. However, because these are generally only observed in isolated groups, or because the evidence is excessively heterogeneous, these associations must be treated with caution.

Impact of Helicobacter pylori eradication on circulating adiponectin in humans

BACKGROUND

The relationship between Helicobacter pylori infection and metabolic syndrome is not well understood. Adiponectin is an adipose-derived protein considered to play a significant role in the development of metabolic syndrome. The aim of this study was to clarify the influence of H. pylori infection on circulating adiponectin in humans.

METHODS

In a prospective study, 456 patients underwent endoscopy and H. pylori testing. All of the 338 H. pylori -positive patients received eradication therapy. Treatment was successful in 241 patients. Circulating adiponectin and other metabolic parameters were measured at baseline in all patients and 12 weeks after eradication therapy in those initially positive for H. pylori.

RESULTS

Circulating adiponectin levels were not different between H. pylori -positive and H. pylori -negative patients. In the group with successful eradication, levels of total adiponectin and each multimer form were significantly increased after therapy. Conversely, the levels of total adiponectin and high-molecular-weight adiponectin, but not middle-molecular-weight and low-molecular-weight adiponectin, were increased in the group with unsuccessful eradication after the therapy.

CONCLUSIONS

Eradication therapy of H. pylori increased circulating adiponectin levels in Japanese individuals and could be beneficial for preventing metabolic syndrome conditions.

Does Helicobacter pylori infection increase incidence of dementia? The Personnes Agées QUID Study

OBJECTIVES

To determine whether Helicobacter pylori infection was associated with dementia and risk of developing dementia in a longitudinal population-based cohort of elderly adults living in the community.

DESIGN

Prospective community-based cohort study.

SETTING

The population-based Personnes Agées QUID (PAQUID) Study.

PARTICIPANTS

Six hundred three noninstitutionalized individuals aged 65 and older living in the southwest of France followed from 1989 to 2008.

MEASUREMENTS

A descriptive and comparative analysis including dementia prevalence, according to H. pylori status (serology), was made at baseline. Cox proportional hazard models were used to study the risk of developing dementia according to H. pylori status assessed on sera samples from elderly adults initially free of dementia and followed for 20 years. A neurologist diagnosed dementia according to Diagnostic and Statistical Manual of Mental Disorders Third Edition criteria.

RESULTS

At baseline, 391 (64.8%) subjects (348 women, mean age 73.9 ± 6.5) were seropositive for H. pylori. Dementia prevalence was higher in the infected group (5.4% vs 1.4%, P = .02). After 20 years of follow-up, 148 incident cases of dementia were diagnosed. After controlling for age, sex, educational level, apolipoprotein E4 status, cardiovascular risk factors, and Mini-Mental State Examination score, H. pylori infection was determined to be a risk factor for developing dementia (hazard ratio = 1.46, P = .04).

CONCLUSION

This longitudinal population-based study provides additional epidemiological support to the hypothesis of an association between dementia and H. pylori infection, which may enhance neurodegeneration.

Association between metabolic syndrome and Helicobacter pylori infection diagnosed by histologic status and serological status

GOALS

We aimed to simultaneously evaluate the association between metabolic syndrome and Helicobacter pylori (HP) infection diagnosed histologically and serologically in a large number of healthy Korean adults.

BACKGROUND

Serological positivity for HP does not necessarily indicate current infection. No study to date has compared the association between metabolic syndrome and HP infection diagnosed by histologic and serological status.

STUDY

HP status was ascertained histologically and serologically in healthy Korean adults who underwent comprehensive health screening in a private health screening center in Korea. Metabolic syndrome was defined according to the International Diabetes Federation definition. Multivariate logistic analyses were performed, after adjusting for potential confounders, including age, sex, smoking, alcohol consumption, and income level.

RESULTS

A total of 5889 subjects were included in the analysis. The metabolic syndrome was more strongly associated with histologic positivity for HP [adjusted odds ratio (aOR)=1.26; 95% confidence interval (CI), 1.08-1.48] than serologic positivity (aOR=1.12, 95% CI, 0.95-1.32), after adjusting for age, sex, smoking status, alcohol consumption, and economic status.

CONCLUSIONS

The stronger association between metabolic syndrome and histologic positivity than serological positivity suggests that the effects of HP infection on the pathogenesis of cardiometabolic outcomes may be reversible. Further prospective studies are needed.

Systematic review and meta-analysis of circulatory disease from exposure to low-level ionizing radiation and estimates of potential population mortality risks

BACKGROUND

Although high doses of ionizing radiation have long been linked to circulatory disease, evidence for an association at lower exposures remains controversial. However, recent analyses suggest excess relative risks at occupational exposure levels.

OBJECTIVES

We performed a systematic review and meta-analysis to summarize information on circulatory disease risks associated with moderate- and low-level whole-body ionizing radiation exposures.

METHODS

We conducted PubMed/ISI Thomson searches of peer-reviewed papers published since 1990 using the terms "radiation" AND "heart" AND "disease," OR "radiation" AND "stroke," OR "radiation" AND "circulatory" AND "disease." Radiation exposures had to be whole-body, with a cumulative mean dose of < 0.5 Sv, or at a low dose rate (< 10 mSv/day). We estimated population risks of circulatory disease from low-level radiation exposure using excess relative risk estimates from this meta-analysis and current mortality rates for nine major developed countries.

RESULTS

Estimated excess population risks for all circulatory diseases combined ranged from 2.5%/Sv [95% confidence interval (CI): 0.8, 4.2] for France to 8.5%/Sv (95% CI: 4.0, 13.0) for Russia.

CONCLUSIONS

Our review supports an association between circulatory disease mortality and low and moderate doses of ionizing radiation. Our analysis was limited by heterogeneity among studies (particularly for noncardiac end points), the possibility of uncontrolled confounding in some occupational groups by lifestyle factors, and higher dose groups (> 0.5 Sv) generally driving the observed trends. If confirmed, our findings suggest that overall radiation-related mortality is about twice that currently estimated based on estimates for cancer end points alone (which range from 4.2% to 5.6%/Sv for these populations).

Coronary atherosclerotic burden in patients with infection by CagA-positive strains of Helicobacter pylori

OBJECTIVES

Cytotoxic associated gene-A (CagA)-positive strains of Helicobacter pylori emerged as a possible atherosclerotic stimulus. Nevertheless, whether CagA-positivity is associated with more extensive or severe atherosclerotic coronary burden has never been studied.

METHODS

Forty consecutive patients with coronary artery disease (CAD) and twenty consecutive patients with normal coronary arteries undergoing coronary angiography were enrolled. All patients underwent evaluation of classical atherogenic risk factors and assessment of anti-urease B and anti-CagA antibodies titer. Either the severity of coronary stenosis (stenosis score) or the extent of coronary atherosclerosis (extent score) was evaluated in CAD patients.

RESULTS

The anti-CagA antibody titer was significantly higher in patients with CAD as compared with normal coronary arteries patients [85 (10-108.75) vs. 47.3 (17-64) RU/ml, P=0.02], whereas there were no differences in anti-urease B titer between the two groups. A significant correlation was found between anti-CagA antibody titer and extent score (R=0.35, P=0.03), whereas stenosis score was similar (R=0.25, P=0.11). On the contrary, no significant correlation was found between anti-urease B antibody titer and either extent or stenosis score. Moreover, CagA-positive patients had a more extensive CAD (P=0.029) when compared with CagA-negative patients. Interestingly, whereas serum glucose, LDL levels, anti-urease B, and anti-CagA antibodies were predictors of extent score at univariate analysis, at multivariate analysis anti-CagA antibody titer only was an independent predictor of the extent of coronary atherosclerosis (B=0.051, standard error of B=0.042, P=0.04).

CONCLUSION

These results support the association between CagA-positive H. pylori infection and coronary atherosclerotic burden. Further studies are needed to better elucidate the mechanism by which CagA-positive strains may promote atherosclerosis.

Review and meta-analysis of epidemiological associations between low/moderate doses of ionizing radiation and circulatory disease risks, and their possible mechanisms

Although the link between high doses of ionizing radiation and damage to the heart and coronary arteries has been well established for some time, the association between lower-dose exposures and late occurring cardiovascular disease has only recently begun to emerge, and is still controversial. In this paper, we extend an earlier systematic review by Little et al. on the epidemiological evidence for associations between low and moderate doses of ionizing radiation exposure and late occurring blood circulatory system disease. Excess relative risks per unit dose in epidemiological studies vary over at least two orders of magnitude, possibly a result of confounding and effect modification by well-known (but unobserved) risk factors, and there is statistically significant (p < 0.00001) heterogeneity between the risks. This heterogeneity is reduced, but remains significant, if adjustments are made for the effects of fractionated delivery or if there is stratification by endpoint (cardiovascular disease vs. stroke, morbidity vs. mortality). One possible biological mechanism is damage to endothelial cells and subsequent induction of an inflammatory response, although it seems unlikely that this would extend to low-dose and low-dose-rate exposure. A recent paper of Little et al. proposed an arguably more plausible mechanism for fractionated low-dose effects, based on monocyte cell killing in the intima. Although the predictions of the model are consistent with the epidemiological data, the experimental predictions made have yet to be tested. Further epidemiological and biological evidence will allow a firmer conclusion to be drawn.

A population-based epidemiologic study of Helicobacter pylori infection and its association with systemic inflammation

BACKGROUND

Infection with Helicobacter pylori is associated with a variety of non-gastrointestinal sequelae. These may be mediated by an increase in systemic inflammation. We assessed if serologic evidence of infection with H. pylori is associated with increased serum C-reactive protein (CRP) levels.

METHODS

The study design consisted of a randomly selected, cross-sectional population-based study of 2633 individuals phenotyped in 1991, of whom 2361 participants provided serum samples to permit measurement of H. pylori's serologic status and CRP levels.

RESULTS

Male gender (odds ratio (OR): 1.65; 95% confidence interval (CI): 1.23-2.21), age (OR per year: 1.05; 95% CI: 1.04-1.06), height (OR per meter: 0.05; 95% CI: 0.01-0.24), current smoking habit (compared with never smokers, OR: 1.46; 95% CI: 1.13-1.88), and less affluent socioeconomic status were associated with increased odds of being seropositive for H. pylori. Helicobacter pylori infection was associated with increased risk of having an elevated serum CRP (above 3 mg/L) after adjustment for gender, age, height, smoking status, and socioeconomic status (OR: 1.32; 95% CI: 1.05-1.67). Similar associations were seen using a threshold for elevated serum CRP of greater than 1 mg/L.

CONCLUSIONS

Our data suggest that infection with H. pylori is associated with increased systemic inflammation. This suggests one potential mechanism to explain the extra-gastrointestinal conditions associated with H. pylori infection.

Possible association of atrophic gastritis and arterial stiffness in healthy middle-aged Japanese

AIM

Helicobacter pylori (HP) has been implicated as a risk factor for cardiovascular and atherosclerotic diseases. Arterial stiffness determined by pulse wave velocity (PWV) or the cardio-ankle vascular index (CAVI) has been shown to be higher in HP-positive subjects than in HP-negative subjects; however, this result has been observed only in young subjects. The aim of the study was to investigate the possible correlation between HP infection and PWV or CAVI in middle-aged subjects.

METHODS

We measured brachial-ankle PWV (baPWV), CAVI, metabolism markers, pepsinogens (PGs) and IgG antibody to HP in 343 individuals aged either 60 or 65 year old. Atrophic gastritis (AG) was diagnosed based on the values of PGs.

RESULTS

baPWV and CAVI were significantly higher in the AG-positive group than in the AG-negative group even after adjusting for possible confounding factors (baPWVc; 16.63+/-3.50 vs. 15.59+/-3.47 p=0.010, CAVIc; 8.59+/-1.20 vs. 8.27+/-1.19 p=0.022). baPWV and CAVI values tended to be higher in the HP-positive group than in the HP-negative group. High-density lipoprotein (HDL) cholesterol level and the adiponectin level were lower in the AG-positive group than in the AG-negative group.

CONCLUSION

There may be an association between atrophic gastritis and atherosclerosis in middle-aged subjects.

CagA antigen of Helicobacter pylori and coronary instability: insight from a clinico-pathological study and a meta-analysis of 4241 cases

BACKGROUND

Cytotoxin-associated gene-A (CagA) antigen is expressed by some virulent strains of Helicobacter pylori (H. pylori). The role of CagA antigen in coronary instability is unknown. We performed a clinico-pathological study and a meta-analysis in the attempt to shed new light on this complex issue.

METHODS

In the clinico-pathological study, 38 patients with unstable angina (UA), 25 patients with stable angina (SA), 21 patients with normal coronary arteries (NCA) and 50 age and sex matched healthy volunteers were enrolled. Serology for CagA was assessed in all patients. Specimens of atherosclerotic plaques were obtained from all patients by directional coronary atherectomy, and prepared for immunohistochemistry using anti-CagA monoclonal antibodies. The meta-analysis includes 9 studies assessing the association between seropositivity to CagA strains and acute coronary events.

RESULTS

The titre of anti-CagA antibodies was significantly higher in patients with unstable angina (161+/-90 RU/ml) compared to those with stable angina (83+/-59 RU/ml p<0.02), NCA (47.3+/-29 RU/ml p<0.01) and healthy controls (73+/-69 p<0.02). Anti-CagA antibodies recognized antigens localized inside coronary atherosclerotic plaques in all specimens from both stable and unstable patients. In the meta-analysis, seropositivity to CagA was significantly associated with the occurrence of acute coronary events with an odds ratio (OR) of 1.34 (95% CI, 1.15-1.58, p=0.0003).

CONCLUSIONS

Taken together these findings suggest that in a subset of patients with unstable angina, an intense immune response against CagA-positive H. pylori strains might be critical to precipitate coronary instability mediated by antigen mimicry between CagA antigen and a protein contained in coronary atherosclerotic plaques.

A systematic review of epidemiological associations between low and moderate doses of ionizing radiation and late cardiovascular effects, and their possible mechanisms

Little, M. P., Tawn, E. J., Tzoulaki, I., Wakeford, R., Hildebrandt, G., Paris, F., Tapio, S. and Elliott, P. A Systematic Review of Epidemiological Associations Between Low and Moderate Doses of Ionizing Radiation and Late Cardiovascular Effects, and Their Possible Mechanisms. Radiat. Res. 169, 99-109 (2008). The link between high doses of ionizing radiation and damage to the heart and coronary arteries is established. In this paper, we systematically review the epidemiological evidence for associations between low and moderate doses (<5 Gy) of ionizing radiation and late-occurring cardiovascular disease. Risks per unit dose in epidemiological studies vary over at least two orders of magnitude, possibly a result of confounding factors. An examination of possible biological mechanisms indicates that the most likely causative effect of radiation exposure is damage to endothelial cells and subsequent induction of an inflammatory response, although it seems unlikely that this would extend to low-dose and low-dose-rate exposure. However, a role for somatic mutation has been proposed that would indicate a stochastic effect. In the absence of a convincing mechanistic explanation of epidemiological evidence that is less than persuasive at present, a cause-and-effect interpretation of the reported statistical associations cannot be reliably inferred, although neither can it be reliably excluded. Further epidemiological and biological evidence will allow a firmer conclusion to be drawn.

[Does Helicobacter pylori infection play a role in extragastric diseases?]

Since the discovery of Helicobacter pylori (H. pylori), numerous studies have considered the possibility that it plays a role in different extragastric diseases. Most of these studies may be classified as epidemiological studies or investigations of H. pylori eradication, but there are also case reports and in vitro studies. This review reveals the limitations common to most of them. Idiopathic thrombocytopenic purpura is the disease for which the strongest association with H. pylori infection has been shown. Data are also accumulating about the role of H. pylori infection in idiopathic iron deficiency anemia and chronic idiopathic urticaria. Interesting results show that H. pylori infection affects atherosclerosis and is weakly associated with ischemic heart disease and stroke. Moreover, CagA-positive H. pylori strains may play a role in the natural history of atherosclerotic stroke. Recent studies suggest a link between H. pylori and Parkinson's disease. Preliminary data indicate that H. pylori infection impairs gastric ghrelin production and may influence nutritional status. The association between H. pylori infection and other extragastric diseases remains controversial. H. pylori infection may cause extragastric manifestations directly or indirectly, by various mechanisms including atrophic gastritis, the release of inflammatory mediators, molecular mimicry, and systemic immune response. Evidence suggests that anti-H. pylori therapy improves idiopathic thrombocytopenic purpura (significant increase of platelet count in half of the cases), iron-deficiency anemia, and chronic urticaria (30% remission rate), but the data from randomized controlled trials are insufficient to confirm these positive effects.

Association between Helicobacter pylori-infection, C-reactive protein and status of B vitamins

PURPOSE

Some investigations, but not all, found that a chronic infection with Helicobacter pylori (Hp) is associated with deficiencies in B vitamins, elevated plasma total homocysteine concentrations (tHcy) and increased plasma levels of proinflammatory acute-phase proteins. It has been suggested that these factors promote atherogenesis and therefore could mechanistically explain why people infected with Hp might have an increased risk for cardiovascular diseases (CVD). Therefore we evaluated the association between Hp-infection, concentration of C-reactive protein (CRP), and status of various B vitamins in apparently healthy subjects.

MATERIAL AND METHODS

In 69 subjects with proved Hp-infection and 21 healthy control subjects identified in a cross sectional study, blood samples were collected to determine serum folate, serum vitamin B12, serum methylmalonic acid (MMA), serum CRP and plasma vitamin B6 and plasma total homocysteine (tHcy).

RESULTS

The mean concentration of CRP was significantly higher in the Hp-positive collective than in controls. Although mean concentrations of vitamin B12, B6, and MMA differed between the groups, statistical significance was missed. However, the mean concentrations of homocysteine and folic acid were nearly the same in both groups. In univariate analysis a significant impact of Hp-status was shown on cobalamin (p=0.028; eta square: 0.055), and in multivariate analysis of variance the Hp-status had an impact on vitamin B12-values (p=0.028; eta square 0.057).

CONCLUSIONS

In this study Hp-infection shows no significant impact on status of B vitamins, but has a significant influence on CRP concentration. However, this study does not support the hypothesis that Hp-infection is related to CVD via elevated levels of tHcy.

The effect of different strains of Helicobacter pylori on platelet aggregation

BACKGROUND AND AIMS

Helicobacter pylori is the major causative agent in peptic ulcer disease and is strongly implicated in the development of gastric cancer. It has also been linked, less strongly, to cardiovascular disease. The mechanisms by which certain strains of H pylori induce platelet aggregation through interactions with platelet glycoprotein Ib have been previously described.

METHODS

In the present study, 21 different strains of H pylori, varying in their vacuolating toxin gene, cytotoxic-associated gene A status and other pathogenicity factors, were tested for their ability to induce platelet aggregation.

RESULTS

Ten of the 21 strains induced platelet aggregation, a response that appeared to be independent of their vacuolating toxin gene and cytotoxic-associated gene A status.

CONCLUSIONS

Platelet aggregation has been suggested to be one of the possible mechanisms involved in the effects on the cardiovascular system induced by H pylori. Our results suggest that any putative role H pylori plays in cardiovascular disease may be strain dependent. Further work to identify the H pylori factors involved in induction of platelet aggregation may allow for identification of 'higher risk' strains for cardiovascular disease.

Involvement of Helicobacter pylori infection and impaired glucose metabolism in the increase of brachial-ankle pulse wave velocity

BACKGROUND

The role of Helicobacter pylori in the pathogenesis of atherosclerosis remains controversial. The present study was designed to elucidate the pathogenic role of H. pylori in the early stages of atherosclerosis by measurement of brachial-ankle pulse wave velocity (baPWV) in relation to glucose metabolism.

MATERIALS AND METHODS

baPWV level, anti-H. pylori antibody, fasting blood glucose (FBG), and glycosylated hemoglobin A1c (HbA1c) and other conventional risk factors for cardiovascular diseases were measured in 947 subjects who attended their annual medical check-up.

RESULTS

Multiple regression analyses indicated that age, gender (male), body mass index, FBG, systolic blood pressure, and smoking habits were each independently related to baPWV values. In younger subjects (30-49 years), H. pylori seropositivity was significantly correlated with an increase of baPWV levels (r = 0.100, p = .0445). baPWV values in the H. pylori-positive subjects with impaired glucose metabolism (IG: FBG >or= 110 mg/dL and/or HbA1c >or= 5.9%) were significantly greater than those in the H. pylori-negative subjects with IG (p = .0078). Furthermore, H. pylori-positive subjects with IG were at higher risk for increase of baPWV, in younger (r = 0.203, p < .0001) as well as in older subjects (50-69 years, r = 0.099, p = .0009).

CONCLUSIONS

These results suggest that H. pylori seropositivity is a potential risk factor for increased baPWV levels, and that H. pylori infection accelerates the effect of IG on an increase of baPWV, especially in younger subjects. Thus, the possible interaction between H. pylori infection and IG may contribute to the early development of atherosclerosis.

The association between current Helicobacter pylori infection and coronary artery disease

BACKGROUND

The role of Helicobacter pylori (H. pylori) in the pathogenesis of coronary artery disease (CAD) is still controversial, and the relation between current H. pylori infection and CAD has not been fully examined. This study evaluated the relation between H. pylori infection as confirmed by gastroduodenoscopic biopsy and CAD.

METHODS

We determined the presence of H. pylori infections, via gastroduodenoscopy, in 88 patients of the normal coronary angiographic group and also in 175 patients of the CAD group, and the latter patients had more than 50% coronary stenosis angiographically demonstrated. We excluded those patients with a history of previous H. pylori eradication and/or malignancy. A small piece of tissue from the antrum, which was obtained by gastroduodenoscopic biopsy, was stained by Warthin-starry silver stain. We defined a negative staining result that there was no stained tissue in the sample and the stained tissue was also positive for H. pylori infection.

RESULTS

There was no significant difference, except for gender, age, smoking and high density lipoprotein cholesterol (HDL-c), of the demographic and laboratory characteristics between the groups. Twenty seven (30.7%) patients of the normal control group and 71 (40.6%) patients of the CAD group were positive of H. pylori infection, yet there was no statistical difference. We angiographically followed up the 80 patients of the CAD group who were treated by percutaneous coronary intervention (PCI) at 6 to 9 months after their primary intervention. Twenty two (37.9%) of the 58 patients of the H. pylori negative group and 10 (45.5%) of the 22 patients of the H. pylori positive group were treated with reintervention, but reintervention was also not significantly different between the group with H. pylori infection and the group without the infection.

CONCLUSIONS

These data indicated that H. pylori infection had a modest influence on CAD and progressive atheroma, but the showed a tendency to increase. Further studies are needed to evaluate the relationship between H. pylori infection and CAD.

A review of the postulated mechanisms concerning the association of Helicobacter pylori with ischemic heart disease

Since its discovery, Helicobacter pylori has been implicated in the pathogenesis of several diseases, both digestive and extradigestive. Interestingly, the majority of the extradigestive-related literature is focused on two vascular manifestations: stroke and ischemic heart disease. Potential mechanisms for the establishment of a H. pylori-induced ischemic heart disease have been proposed with regard to chronic inflammation, molecular mimicry, oxidative modifications, endothelial dysfunction, direct effect of the microorganism on atherosclerotic plaques as well as changes regarding traditional or novel risk factors for ischemic heart disease or even platelet-H. pylori interactions. A positive link between H. pylori infection and ischemic heart disease has been suggested by a series of studies focusing on epidemiologic evidence, dyslipidemic alterations, upregulation of inflammatory markers or homocysteine levels, induction of hypercoagulability, oxidation of low-density lipoprotein, causation of impaired endothelial function, detection of H. pylori DNA in atherosclerotic plaques, and participation of certain antigens and antibodies in a cross-reactivity model. There are studies, however, which investigated the relationship between H. pylori and ischemic heart disease with regard to the same parameters and failed to confirm the suggested positive association. Further studies in the direction of interaction between H. pylori and the host's genotype as well as a quest for evidence towards novel risk factors for ischemic heart disease such as oxidative stress, vascular remodeling, vascular calcification, or vasomotor activity, may reveal a field of great interest, thus contributing to the determination of new potential mechanisms.

Helicobacter pylori-associated atrophic gastritis and carotid intima-media thickness: is there a link?

Chronic infections are associated with cardiovascular diseases. Helicobacter pylori-induced chronic active gastritis results in atrophic gastritis. In this study, we attempted to determine carotid intima-media thickness in patients with and individuals without H. pylori-induced atrophic gastritis. Oesophagogastroduodenoscopy was performed on 123 patients for various reasons. Helicobacter pylori were considered positive when histological examination and rapid urease test showed H. pylori. Helicobacter pylori-positive cases were divided into two groups, namely atrophic gastritis and non-atrophic gastritis. Of 123 patients, 92 patients had H. pylori-positive non-atrophic gastritis and 31 had H. pylori-positive atrophic gastritis. There was no significant difference in carotid intima-media thickness between the two groups. Carotid intima-media thickness is not associated with H. pylori-induced atrophic gastritis.

H pylori infection and systemic antibodies to CagA and heat shock protein 60 in patients with coronary heart disease

AIM: To determine the overall prevalence of H pylori and CagA positive H pylori infection and the prevalence of other bacterial and viral causes of chronic infection in patients with coronary heart disease (CHD), and the potential role of anti-heat-shock protein 60 (Hsp60) antibody response to these proteins in increasing the risk of CHD development.

METHODS: Eighty patients with CHD and 160 controls were employed. We also compared the levels of anti-heat-shock protein 60 (Hsp60) antibodies in the two groups. The H pylori infection and the CagA status were determined serologically, using commercially available enzyme-linked immunosorbent assays (ELISA), and a Western blotting method developed in our laboratory. Systemic antibodies to Hsp60 were determined by a sandwich ELISA, using a polyclonal antibody to Hsp60 to sensitise polystyrene plates and a commercially available human Hsp60 as an antigen.

RESULTS: The overall prevalence of H pylori infection was 78.7% (n = 63) in patients and 76.2% (n = 122) in controls (P = 0.07). Patients infected by CagA-positive (CagA⁺) H pylori strains were 71.4% (n = 45) vs 52.4% of infected controls (P = 0.030, OR = 2.27). Systemic levels of IgG to Hsp60 were increased in H pylori-negative patients compared with uninfected controls (P < 0.001) and CagA-positive infected patients compared with CagA-positive infected controls (P = 0.007).

CONCLUSION: CagA positive H pylori infection may concur to the development of CHD; high levels of anti-Hsp60 antibodies may constitute a marker and/or a concomitant pathogenic factor of the disease.

Virulent strains of Helicobacter pylori and vascular diseases: a meta-analysis

BACKGROUND

Cytotoxin-associated gene A (CagA)-positive strains of Helicobacter pylori are an etiological factor for peptic ulcer and gastric cancer. Studies on the role of these virulent strains in vascular diseases yield conflicting results.

METHODS

We searched the MEDLINE database for relevant studies. Meta-analysis was performed using the random effects method.

RESULTS

We found 10 retrospective case-control studies (with 1527 case patients and 1661 control subjects) and 3 prospective cohort studies (with 701 case patients and 1439 control subjects) on CagA status and ischemic heart disease and 4 retrospective case-control studies (with 513 case patients and 590 control subjects) on CagA status and cerebral ischemia. In the case-control studies, an association of ischemic heart disease with CagA-positive strains (OR 1.87, 95% CI 1.46-2.40) but no significant association with CagA-negative strains (OR 1.15, 95% CI 0.83-1.60) has been found; in the 3 prospective studies, association with ischemic heart disease was weaker but still significant (OR 1.26, 95% CI 1.05-1.51). In the 4 case-control studies, CagA-positive strains were significantly associated with cerebral ischemia (OR 2.43, 95% CI 1.89-3.13), again with no association for CagA-negative strains.

CONCLUSIONS

We found a small but significant association between vascular diseases and virulent CagA-positive strains of H. pylori. The lack of association with CagA-negative strains further supports the hypothesis of an independent relationship between virulent strains of H. pylori and vascular diseases. The magnitude of the association with cerebral ischemia needs to be confirmed by prospective studies.

Vacuolating cytotoxin A is associated with increased thrombin generation in gastric mucosa

BACKGROUND

Activation of the coagulation system is a critical response for both the repair of tissue injury and the host defense against microbial pathogens. Activation of the coagulation cascade culminates with the generation of thrombin. In vitro studies have shown that thrombin protects gastric epithelial cells from injury. The present study was undertaken to assess in vivo the relationship between gastric intramucosal generation of thrombin and Helicobacter pylori infection.

MATERIALS AND METHODS

This study comprised 59 patients with gastroduodenal disorders. There were 27 patients with H. pylori infection (Hp+), 14 without it (Hp-), and 18 patients with cured H. pylori infection (Hp c). The gastric intramucosal concentrations of thrombin-antithrombin complex (TAT), epidermal growth factor (EGF), prostaglandin E2 (PGE2), and vacuolating cytotoxin A (VacA) were measured by specific immunoassays.

RESULTS

The level of TAT was significantly increased in patients with Hp+ compared to Hp- and Hp c. The levels of TAT, EGF and PGE2 were higher in VacA (+) patients than in those with VacA (-). VacA induced significant expression of tissue factor in gastric epithelial cells in vitro. The gastric intramucosal level of VacA antigen was proportionally and significantly correlated with TAT, EGF and PGE2 in Hp+ patients. The level of TAT was proportionally and significantly correlated with EGF in Hp+ patients but not in Hp- and HP c patients.

CONCLUSIONS

These results showed that VacA produced by H. pylori is associated with increased thrombin generation, and that thrombin may play a protective role in H. pylori-associated gastroduodenal disorders.

Acute coronary syndrome and chronic infection in the Cork coronary care case-control study

OBJECTIVE

To examine the association between chronic infection and cumulative burden of infection and acute coronary syndrome.

DESIGN

The 5C (Cork coronary care case-control) study was a community based case-control study. Patients and controls underwent a standard physical examination and had blood samples taken for serological analysis for Helicobacter pylori (IgG), Chlamydia pneumoniae (IgA, IgM, and IgG), cytomegalovirus (IgG), and herpes simplex virus types 1 and 2 (IgG).

SETTING

Patients were recruited from four hospitals in Cork City and Mallow Town. Controls, individually matched on age and sex, were selected by incident density sampling from the same general practices as the referent case.

MAIN OUTCOME MEASURES

Age and sex adjusted and fully adjusted odds ratios for acute coronary syndrome by seropositivity and by increasing number of infections.

RESULTS

Cases and controls did not differ significantly in seropositivity to C pneumoniae, cytomegalovirus, herpes simplex viruses, and H pylori. In unconditional logistic regression analysis adjusted for age, sex, waist to hip ratio, smoking, physical activity, alcohol consumption, and social class there was no evidence of an increasing risk for acute coronary syndrome with increasing burden of infection.

CONCLUSIONS

The findings do not support an association between specific infectious agents and acute coronary syndrome and do not provide evidence of a burden of infection effect.

Association of CagA+ Helicobacter pylori infection with aortic atheroma

BACKGROUND

To investigate possible association between infection with CagA(+) strains of Helicobacter pylori and aortic atheroma diagnosed by transesophageal echocardiography.

METHODS AND RESULTS

One hundred and eighty-eight consecutive subjects prospectively examined for presence of aortic atheroma (localized intimal thickening of >/=3mm) by transesophageal echocardiography were tested for serum IgG antibodies against H. pylori (enzyme-linked immunosorbent assay) and CagA protein (Western blot assay). The association between infection with H. pylori, CagA status of the infecting H. pylori strains, and aortic atherosclerosis was evaluated after adjusting for coronary artery disease risk factors. There was a linear trend for presence of atheroma in subjects with CagA-positive H. pylori infection (51/81, 63%) compared to subjects with CagA-negative H. pylori infection (21/45, 46.7%) and uninfected subjects (18/62, 29%) (p=0.003). H. pylori seropositivity was not associated with aortic atheroma (OR 2.9; 95% CI, 0.8-10.3; p=0.11) when CagA status is not taken into account. On multivariate analysis, parameters associated with risk of aortic atheroma were CagA-positive H. pylori seropositivity (OR 4.4; 95% CI, 1.4-14.7; p=0.01), older age (OR 1.2; 95% CI, 0.9-14.7; p=0.01), having ever smoked cigarettes (OR 3.6; 95% CI, 1.3-10.0; p<0.001), and elevated serum triglyceride level (OR 3.4; 95% CI, 1.3-9.4; p=0.02).

CONCLUSIONS

After controlling for H. pylori infection and coronary artery disease risk factors, infection with a CagA-positive strain of H. pylori was independently associated with aortic atherosclerosis. This study suggests a gradient of atherosclerosis between uninfected individuals and patients with CagA-positive H. pylori infection and should prompt research into the role of CagA-positive H. pylori infection in the inflammatory atherosclerotic process.

Effects of Helicobacter pylori eradication on platelet activation and disease recurrence in patients with acute coronary syndromes

BACKGROUND

Platelet activation is consistently observed in animal models of Helicobacter pylori infection and could help to explain the alleged epidemiological association between H. pylori and coronary heart disease.

MATERIALS AND METHODS

Ninety-two patients with recent acute coronary syndromes were enrolled. Helicobacter pylori-positive patients were randomized to receive a 7-day course of omeprazole, amoxycillin and metronidazole or placebos. Two months later, H. pylori status was reassessed and baseline parameters, including soluble P-selectin and platelet surface expression of CD62P, CD63 and CD41, were measured again. Patients were followed-up for 1 year or until death or readmission.

RESULTS

No baseline differences were observed between H. pylori-positive and -negative cases. Among H. pylori-positive patients, 18 received placebo and 31 received active medication resulting in eradication in 21 cases. No differences were observed in inflammatory parameters or platelet activation markers between patients with persistent or resolved H. pylori infection. However, coronary events recurred at 6 and 12 months, respectively, in 35% and 55% of patients with persisting H. pylori infection compared with 10% and 25% of patients in whom H. pylori was either absent or eradicated (p = .01). Only final H. pylori status [RR 3.07 (95% CI 1.35-98)] and number of coronary risk factors [RR 2.58 (95% CI 1.51-4.41)] were independent predictors of recurrence.

CONCLUSIONS

Infection with H. pylori does not induce significant platelet activation in patients treated for coronary disease. Helicobacter pylori-infected patients, however, may have an increased risk of recurrence of coronary events.

Oxidized low-density lipoprotein levels circulating in plasma and deposited in the tissues: comparison between Helicobacter pylori-associated gastritis and acute myocardial infarction

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) is a key factor in the progression of atherosclerosis. We developed a sensitive method for measuring plasma ox-LDL levels using a novel anti-ox-LDL antibody. Recently, several studies have shown positive associations between Helicobacter pylori (H pylori) infection and coronary heart disease. Thus the question arises whether an increase in the plasma levels of ox-LDL occurs in patients with H pylori gastritis.

METHODS

We measured plasma ox-LDL levels in patients with H pylori gastritis (n = 27) and compared them with those in patients with acute myocardial infarction (AMI) (n = 62) and stable angina pectoris (SAP; n = 63) and those in control subjects (n = 64). In addition, ox-LDL localization and the presence of macrophages and neutrophils were studied immunohistochemically in gastritis specimens and in coronary culprit lesions obtained from patients with AMI.

RESULTS

Plasma ox-LDL levels in patients with AMI were significantly higher than those in patients with SAP (P <.0001), patients with H pylori gastritis (P <.0001), or in control subjects (P <.0001; AMI, 1.34 +/- 0.95; SAP, 0.61 +/- 0.29; Gastritis, 0.53 +/- 0.17; control, 0.57 +/- 0.23 ng/5 microg LDL protein). Immunohistochemically, H pylori gastritis specimens showed distinct infiltration of macrophages and myeloperoxidase-positive neutrophils; however, ox-LDL localization was not detected. In contrast, coronary culprit plaques revealed strong positivity for ox-LDL in ruptured lipid cores with abundant macrophage-derived foam cells, and these plaques also contained myeloperoxidase-positive neutrophils.

CONCLUSION

Our results suggest that plasma ox-LDL levels do not seem to be associated with H pylori infection, but do relate to coronary plaque instability in AMI.