Relationship between infectious burden, systemic inflammatory response, and risk of stable coronary artery disease: role of confounding and reference group

Mendelian randomization analysis using multiple biomarkers of an underlying common exposure

Mendelian randomization (MR) analysis is increasingly popular for testing the causal effect of exposures on disease outcomes using data from genome-wide association studies. In some settings, the underlying exposure, such as systematic inflammation, may not be directly observable, but measurements can be available on multiple biomarkers or other types of traits that are co-regulated by the exposure. We propose a method for MR analysis on latent exposures (MRLE), which tests the significance for, and the direction of, the effect of a latent exposure by leveraging information from multiple related traits. The method is developed by constructing a set of estimating functions based on the second-order moments of GWAS summary association statistics for the observable traits, under a structural equation model where genetic variants are assumed to have indirect effects through the latent exposure and potentially direct effects on the traits. Simulation studies show that MRLE has well-controlled type I error rates and enhanced power compared to single-trait MR tests under various types of pleiotropy. Applications of MRLE using genetic association statistics across five inflammatory biomarkers (CRP, IL-6, IL-8, TNF-α, and MCP-1) provide evidence for potential causal effects of inflammation on increasing the risk of coronary artery disease, colorectal cancer, and rheumatoid arthritis, while standard MR analysis for individual biomarkers fails to detect consistent evidence for such effects.

Causality of anti-Helicobacter pylori IgG levels on myocardial infarction and potential pathogenesis: a Mendelian randomization study

Background

Previous observational studies have shown that a potential relationship between anti-Helicobacter pylori (H. pylori) IgG levels and Myocardial Infarction (MI). Nevertheless, the evidence for the causal inferences remains disputable. To further clarify the relationship between anti-H. pylori IgG levels and MI and explore its pathogenesis, we conducted a Mendelian randomization (MR) analysis.

Methods

In this study, we used two-sample Mendelian Randomization (MR) to assess the causality of anti-H. pylori IgG levels on MI and potential pathogenesis, 12 single nucleotide polymorphisms (SNPs) related to anti-H. pylori IgG levels were obtained from the European Bioinformatics Institute (EBI). Summary data from a large-scale GWAS meta-analysis of MI was utilized as the outcome dataset. Summary data of mediators was obtained from the FinnGen database, the UK Biobank, the EBI database, MRC-IEU database, the International Consortium of Blood Pressure, the Consortium of Within family GWAS. Inverse variance weighted (IVW) analysis under the fixed effect model was identified as our main method. To ensure the reliability of the findings, many sensitivity analyses were performed.

Results

Our study revealed that increases of anti-H. pylori IgG levels were significantly related to an increased risk of MI (OR, 1.104; 95% CI,1.042-1.169; p = 7.084 × 10-4) and decreases in HDL cholesterol levels (β, -0.016; 95% CI, -0.026 to -0.006; p = 2.02 × 10-3). In addition, there was no heterogeneity or pleiotropy in our findings.

Conclusion

This two-sample MR analysis revealed the causality of anti-H. pylori IgG levels on MI, which might be explained by lower HDL cholesterol levels. Further research is needed to clarify the results.

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.

Abdominal aortic aneurysm and virus infection: A potential causative role for cytomegalovirus infection?

An abdominal aortic aneurysm (AAA) is a multifactorial disease with a variety of genetic and environmental risk factors, but the exact mechanism of AAA formation and progression is still not well understood. The present study investigated the frequency of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and papillomavirus types 6 and 11 (HPV6 and HPV11), their impact on clinical manifestations of cardiovascular diseases, and their possible association with inflammation in patients with AAA and healthy volunteers. Genotyping of CMV UL75, EBV LMP-1, and HPV6, and HPV11 E6 was performed by polymerase chain reaction (PCR), while the viral DNA loads were measured by quantitative real-time PCR. Cytokine levels were determined by enzyme-linked immunosorbent assays. The CMV UL75 was detected more frequently in the blood of patients with AAA than in the blood of healthy volunteers (32.7% vs. 6.3%, p < .0001). Neither EBV LMP-1 nor HPV6 E6 was found in blood and aortic wall biopsies, while the HPV11 E6 was detected in 36.4% of AAA walls. The CMV infection in patients with AAA was associated with an increased risk of hypertension and coronary artery disease (OR, 9.057; 95% CI, 1.141-71.862; p = .037; and OR, 2.575; 95% CI, 1.002-6.615; p = .049, respectively). Additionally, CMV-infected patients with AAA had higher tumor necrosis factor-α levels compared with noninfected subjects (p = .017). Our findings suggest that CMV infection can stimulate local inflammation in the aorta but is not a direct cause of most abdominal aortic aneurysms.

Ethnic differences in infectious burden and the association with metabolic risk factors for cardiovascular disease: a cross-sectional analysis

Background

The burden of metabolic risk factors for cardiovascular disease (CVD), such as type 2 diabetes, elevated cholesterol and hypertension, is unequally distributed across ethnic groups. Recent findings suggest an association of infectious burden (IB) and metabolic risk factors, but data from ethnic groups are scarce. Therefore, we investigated ethnic differences in IB and its association with metabolic risk factors.

Methods

We included 440 Dutch, 320 Turkish and 272 Moroccan participants, 18–70 years, of the 2004 general health survey in Amsterdam, the Netherlands. IB was defined by seropositivity to the sum of 6 infections: Herpes Simplex Virus 1 and 2; Hepatitis A, B and C; and Helicobacter pylori. Associations between IB categories 4–6 (high), 3 (intermediate) and 0–2 (low) infections and metabolic risk factors were assessed by logistic regression. Finally, we determined the contribution of IB to the association between ethnicity and the metabolic risk factors by comparing adjusted logistic regression models with and without IB categories.

Results

A high IB was more frequently observed among the Turkish and Moroccans than among the Dutch. After adjustment for age, sex, ethnicity, educational level, physical activity and body mass index, high IB was associated with type 2 diabetes (odds ratio high vs low IB (OR) =2.14, 95%-confidence interval (CI) 1.05–4.36). The association was weaker and not statistically significant, for elevated cholesterol (OR = 1.39, 95%-CI 0.82–2.34) and hypertension (OR = 1.49, 95%-CI 0.88–2.51). IB attenuated ethnic differences particularly for type 2 diabetes.

Conclusions

Our study showed that Turkish and Moroccan adults in Amsterdam have a higher IB than Dutch adults, which was associated with the differences in type 2 diabetes. Due to the cross-sectional nature of the study, we cannot draw a conclusions with regards to the time-sequence of cause and effect. Nevertheless, the findings ask for further research into the nature of association of IB with metabolic risk factors in a longitudinal setting.

Prevalence of bacteria in the circulation of cardiovascular disease patients, Madurai, India

Cardiovascular diseases (CVDs) have a complex aetiology determined by risk factors, which include genetic and environmental factors. Chronic infection and inflammation is reported to be a pathogenic determinant for the development of CVDs. Here, we report the prevalence of bacterial pathogens in the circulation of CVD patients in Madurai, India. Blood culturing was performed using BD BACTEC automated culture system and organisms were identified by16S rRNA gene sequence analysis. From a total of 133 samples screened, 47 samples showed culture positive which indicates a high level of bacteraemia in CVD patients. From the 47 samples that showed growth, we have identified 57 bacterial isolates comprising 35 different species. Coagulase negative Staphylococci (CoNS) was the most predominant group of bacteria and other notable bacterial species isolated in this study are discussed.

Molecular survey of atheromatous plaques for the presence of DNA from periodontal bacterial pathogens, archaea and fungi

BACKGROUND AND OBJECTIVE

Chronic infections, such as periodontitis, have been associated with the development and progression of atherosclerosis. The mechanisms through which this occurs have yet to be elucidated. This study was carried out to detect periodontopathic bacteria as well as archaea and fungi in atheromatous plaques and search for factors associated with their occurrence in atheromas.

MATERIAL AND METHODS

  A cross-sectional study was carried out including 30 patients diagnosed with atherosclerosis in the carotid, coronary or femoral arteries. Plaques were collected during surgery and analysed using PCR to detect Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola and members of the Synergistetes group. Samples were also surveyed with universal primers for bacterial, archaeal and fungal DNA. Patients responded to a questionnaire to determine factors associated with PCR results.

RESULTS

All dentate individuals (66.7%) had periodontal disease, 95% of which was severe and 65% extensive. None of the targeted periodontopathic bacteria was found in the atheromas. No sample yielded positive results for fungal and archaeal DNA. Four samples (13%) were positive for the presence of bacterial DNA. Of these, three participants were dentate (two with severely chronic generalized periodontitis and one with severely chronic localized periodontitis).

CONCLUSION

This study did not confirm previous findings of periodontal pathogens in atheromas, making it impossible to establish factors associated with their presence in plaques. Presence of bacterial DNA in some samples indicates that periodontal or nonoral bacterial species other than the ones targeted in this study may be involved with some cases of atherosclerosis.

The influence of persistent pathogens on circulating levels of inflammatory markers: a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis

Background

Systemic inflammation is linked to cardiovascular risk, but the influence of persistent pathogens, which are conventionally dichotomously categorized, on circulating levels of inflammatory markers is not clear. Antibody levels of pathogens have not been examined in relation to inflammation.

Methods

Using data from a subsample of the Multi-Ethnic Study of Atherosclerosis, we examined circulating levels of interleukin-6 (IL-6), C-reactive protein (CRP) and fibrinogen in relation to five common persistent pathogens: cytomegalovirus, herpes simplex virus-1, Hepatitis A virus, Helicobacter pylori and Chlamydia pneumoniae. We tested the hypothesis that the number of seropositive pathogens (based on conventional cut-off points) would not be as sensitive a marker of inflammation as immune response measured by antibody levels to pathogens.

Results

High antibody response to multiple pathogens showed graded and significant associations with IL-6 (p < 0.001), CRP (p = 0.04) and fibrinogen (p = 0.001), whereas seropositive pathogen burden did not. In multiple linear regression models, high antibody response to multiple pathogens maintained a positive association only with IL-6 (4.4% per pathogen exhibiting high antibody response, 95% CI 0.0-8.9).

Conclusions

High antibody response to pathogens was a more consistent marker of inflammatory outcomes compared to seropositivity alone and high antibody response to multiple pathogens was a stronger marker compared to any single pathogen.

Mycotic DNA in non-atherosclerotic aortic wall of coronary patients is associated with sICAM-1 expression

BACKGROUND

Atherosclerosis is currently being investigated as a chronic inflammatory process and the role of infectious agents is unclear. The presence of mycotic DNA in the wall of the non-atherosclerotic aorta of patients with coronary artery disease (CAD) and its association with levels of soluble intercellular adhesion molecule (sICAM)-1 expression was examined in the present study.

METHODS AND RESULTS

In 40 patients with CAD and a comparative group of 20 patients with aortic valve stenosis (AS) without CAD, specimens of the aortic wall were obtained during cardiac surgery. Mycotic DNA was analyzed by polymerase chain reaction (PCR) using a fungus-specific universal primer pair, ITS3 and ITS4, to amplify a portion of the 5.8S rDNA region, the entire ITS2 region and a portion of the 28S rDNA region, and using a species-specific primer pair, CALB1 and CALB2, to specifically amplify Candida (C.) albicans. The nested PCR method was performed to amplify the intergenic transcribed spacer regions of the rRNAs of Candida species. Before surgery the serum level of sICAM-1 was estimated. Mycotic DNA was detected in 48% of the CAD patients and in 40% of the AS patients, with C. albicans DNA in 58% and 100%, respectively (P>0.05). In CAD patients with a high level of sICAM-1, C. albicans DNA was found more frequently than in patients without elevated levels of sICAM-1 (P<0.05).

CONCLUSIONS

Mycotic DNA was found in the non-atherosclerotic aortic wall of CAD patients as well as in patients with AS. In the CAD patients C. albicans DNA was related to sICAM-1 expression.

Socioeconomic and psychosocial gradients in cardiovascular pathogen burden and immune response: the multi-ethnic study of atherosclerosis

BACKGROUND

The biologic mechanisms linking socioeconomic position and psychosocial factors to cardiovascular disease (CVD) are not well understood. Immune response to persistent pathogens may be one of these mechanisms.

METHODS

We analyzed cross-sectional data from the multi-ethnic study of atherosclerosis (N=999) composed of adults age 45-84. Log-binomial regression and ordinal logistic regression models were used to examine associations of socioeconomic factors and psychosocial factors with pathogen burden and immune response among those infected. Pathogen burden was assessed based on seroprevalence of Helicobacter pylori, cytomegalovirus, herpes simplex virus-1, and Chlamydia pneumoniae and antibody levels were used to characterize high immune response to all four pathogens.

RESULTS

Low education was a strong and significant independent predictor of higher pathogen burden after adjustment for covariates (adjusted odds ratio (OR) 95% confidence interval (CI) 1.37, 1.19-1.57). Among subjects seropositive for all four pathogens, low education and a higher level of chronic psychosocial stress showed a positive association with higher antibody response, although associations were no longer significant in models with all covariates included (OR=1.64, 95% CI 0.82-3.31 for lowest vs. highest educational category and OR=1.29, 95% CI 0.96-1.73 for a one level increase in chronic stress).

CONCLUSION

Pathogen burden and heightened immune response may represent a biological pathway by which low socioeconomic position and chronic stress are related to increased rates of cardiovascular disease.

Airways inflammation and treatment during acute exacerbations of COPD

INTRODUCTION

Inflammation is a core feature of acute chronic obstructive pulmonary disease (COPD) exacerbations. It is important to focus on inflammation since it gives insight into the pathological changes causing an exacerbation, thereby possibly providing directions for future therapies which modify inflammation.

OBJECTIVES

To provide a cell-by-cell overview of the inflammatory processes during COPD exacerbations. To evaluate cell activation, and cytokine production, cellular interactions, damaging effects of inflammatory mediators to tissue, and the relation to symptoms at the onset of COPD exacerbations. To speculate on future therapeutic options to modify inflammation during COPD exacerbations.

RESULTS

During COPD exacerbations, there is increased airway wall inflammation, with pathophysiological influx of eosinophils, neutrophils, and lymphocytes. Although links have been suggested between the increase in eosinophils and lymphocytes and a viral etiology of the exacerbation, and between the increase in neutrophils and a bacterial aetiology, these increases in both inflammatory cell types are not limited to the respective aetiologies and the underlying mechanisms remain elusive.

CONCLUSION

Further research is required to fully understand the inflammatory mechanisms in the onset and development of COPD exacerbations. This might make inflammatory pathway-specific intervention possible, resulting in a more effective treatment of COPD exacerbations with fewer side effects.

Single-stranded polyinosinic acid oligonucleotides trigger leukocyte production of proteins belonging to fibrinolytic and coagulation cascades

The present study assessed the inductory effects of ds- and ssRNA on the leukocyte production of proteins belonging to fibrinolytic and coagulation cascades. Murine splenocytes were stimulated with dsRNA [polyinosinic:polycytidylic acid (polyIC)] and ssRNA sequences [polyinosinic acid (polyI), polycytidylic acid (polyC), and polyuridylic acid (polyU)]. The expression of plasminogen (Plg), tissue factor (TF), IL-6, and IFN-alpha was assessed. Intracellular transduction mechanisms activated by oligonucleotides were evaluated using specific inhibitors of signaling pathways and genetically modified mice. polyIC efficiently and dose-dependently induced the expression of Plg, IL-6, and IFN-alpha, whereas TF was not induced by polyIC. polyI was unable to trigger IFN-alpha production, and it was efficiently inducing Plg and TF. IFN-alphaR and dsRNA-dependent protein kinase signaling were not required for the polyI-induced production of Plg or TF. Neither polyU nor polyC induced the expression of Plg or TF. Importantly, the presence of U- and C-nucleotide strands in the dsRNA significantly reduced expression of Plg and TF compared with polyI alone. Exposure of splenocytes to polyI activated the NF-kappaB pathway followed by the expression of TF and IL-6. In contrast, Plg production did not require NF-kappaB, was only partly down-regulated by p38 MAPK inhibitor, and was efficiently inhibited by insulin, indicating a different mechanism for its induction. ssRNA exerts its TF-generating properties through NF-kappaB activation in an IFN-alpha-independent manner. The expression of fibrinolytic versus coagulation proteins is regulated through distinctly different transduction pathways. As fibrinolytic and coagulation cascades are important components of inflammatory homeostasis, these findings might have importance for development of new, targeted therapies.

The effects of metabolic syndrome versus infectious burden on inflammation, severity of coronary atherosclerosis, and major adverse cardiovascular events

BACKGROUND

The clinical predictors of inflammation in atherosclerosis remain controversial. The objective of this study was to compare the associations of metabolic factors vs. infectious burden (IB) with inflammation, the severity of coronary atherosclerosis, and major adverse cardiovascular events (MACEs).

DESIGN, SETTING, AND PATIENTS

Coronary angiography with Gensini score was applied to assess the severity of coronary atherosclerosis in 568 patients with coronary artery disease. Metabolic syndrome (MS) score (0-5) was defined according to the modified criteria of National Cholesterol Education Program Adult Treatment Panel III. IB score (0-7) was defined as the number of seropositivities to several agents.

RESULTS

IB score was not associated with plasma C-reactive protein (CRP) concentration, Gensini score, or the risk of MACE. In contrast, MS score significantly correlated with both plasma CRP concentration and Gensini score (P < 0.001 for both). MS score and plasma CRP concentration were also significantly associated with the risk of MACE (hazard ratios 1.51, P < 0.001; and 1.90, P = 0.002, respectively).

CONCLUSION

Compared with IB, metabolic abnormalities have a more prominent association with the degree of inflammation, the severity of coronary atherosclerosis, and the risk of MACE in patients with coronary artery disease.

Socioeconomic status, pathogen burden and cardiovascular disease risk

OBJECTIVE

Socioeconomic status (SES) is inversely associated with coronary heart disease (CHD) risk. Cumulative pathogen burden may also predict future CHD. The hypothesis was tested that lower SES is associated with a greater pathogen burden, and that pathogen burden accounts in part for SES differences in cardiovascular risk factors.

METHODS

This was a cross-sectional observational study involving the clinical examination of 451 men and women aged 51-72 without CHD, recruited from the Whitehall II epidemiological cohort. SES was defined by grade of employment, and pathogen burden by summing positive serostatus for Chlamydia pneumoniae, cytomegalovirus and herpes simplex virus 1. Cardiovascular risk factors were also assessed.

RESULTS

Pathogen burden averaged 1.94 (SD) 0.93 in the lower grade group, compared with 1.64 (0.97) and 1.64 (0.93) in the intermediate and higher grade groups (p = 0.011). Pathogen burden was associated with a higher body mass index, waist/hip ratio, blood pressure and incidence of diabetes. There were SES differences in waist/hip ratio, high-density lipoprotein-cholesterol, fasting glucose, glycated haemoglobin, lung function, smoking and diabetes. The SES gradient in these cardiovascular risk factors was unchanged when pathogen burden was taken into account statistically.

CONCLUSIONS

Although serological signs of infection with common pathogens are more frequent in lower SES groups, their distribution across the social gradient does not match the linear increases in CHD risk present across higher, intermediate and lower SES groups. Additionally, pathogen burden does not appear to mediate SES differences in cardiovascular risk profiles.

The Impact on Coronary Artery Disease of Common Polymorphisms Known to Modulate Responses to Pathogens

There are two distinct models to explain how genetic variants contributing to cardiovascular disease may have arisen. Firstly, variants may result from random, initially neutral, mutations whose effects are largely revealed in post-reproductive individuals in industrialized societies. Alternatively, the introduced variants may confer an adaptive advantage in certain circumstances. Resistance to pathogens is one of the strongest selection pressures on human proteins. To determine whether this evolutionary pressure has made a large contribution to heart disease we tested whether seventeen polymorphisms in fourteen innate-immunity genes, with documented evidence of modulating response to pathogens, had an impact on heart disease. Genotyping was performed in 1,598 CAD subjects (ACS or stable angina) and 332 controls. The TLR4 399Ile allele had the greatest impact on ACS risk (uncorrected p = 0.006); however there was no evidence overall that the resistance alleles cumulatively influenced the risk of ACS compared to controls or stable angina patients (p = 0.12, and p = 0.40, respectively). We did note a significant interaction between age at onset of disease and combined resistance allele carriership when the ACS and non-thrombotic, stable angina groups were compared (p = 0.04, 16 d.f.). This suggests that innate immunity factors could have a greater impact on thrombus formation among younger CAD patients.

Dysregulated Toll-like receptor expression and signaling in bone marrow-derived macrophages at the onset of diabetes in the non-obese diabetic mouse

The expression, responsiveness and regulation of mouse Toll-like receptors (TLRs) in bone marrow-derived macrophages (BM-Ø) were investigated prior to and following the development of diabetes. Expression of TLR3 and TLR5 was significantly higher in newly diabetic non-obese diabetic (NOD) mice when compared with pre-diabetic and control strains of mice. The TLR3 ligand poly(I)poly(C) triggered up-regulation of its own receptor in NOR and pre-diabetic NOD, but TLR3 was already highly expressed in diabetic NOD mice. Expression levels of TLR3 correlated with poly(I)poly(C)-triggered IFN activity. LPS triggered down-regulation of TLR4 in pre-diabetic NOD, NOR and BALB/c, while levels of TLR4 remained consistently elevated in type 1 diabetic NOD and type 2 diabetic NZL mice. Dysregulation of TLR4 expression in the diabetic state correlated with increased nuclear factor kappa B (NF-kappaB) activation in response to the TLR4 ligand LPS and higher expression of IL-12p40, tumor necrosis factor alpha (TNFalpha), IL-6 and inducible nitric oxide synthase but lowered expression of IL-10. Exposure of bone marrow precursor cells from NOD mice to a hyperglycemic environment during differentiation into macrophages resulted in elevated levels of TLR2 and TLR4 and the cytokine TNFalpha. The results indicate that macrophage precursors are influenced by systemic changes in diabetes favoring altered TLR expression and sensitivity that may influence susceptibility to macrophage-mediated diabetes complications and explain inappropriate responses to infection in diabetes.

Prognostic value of interleukin-1 receptor antagonist gene polymorphism and cytomegalovirus seroprevalence in patients with coronary artery disease

Background

Chronic inflammatory stimuli such as cytomegalovirus (CMV) infection and various genetic polymorphisms determining the inflammatory response are assumed to be important risk factors in atherosclerosis. We investigated whether patients with stable coronary artery disease (CAD) and homozygous for allele 2 of the interleukin 1 receptor antagonist (IL-1RA) gene and seropositive for CMV represent a group particular susceptible for recurrent cardiovascular events.

Methods

In a series of 300 consecutive patients with angiographically defined CAD a prospective follow-up was conducted (mean age 57.9 years, median follow-up time 38.2 months).

Results

No statistically significant relationship was found between CMV serostatus and IL-1RN*2 (alone or in combination) and risk for future cardiovascular events (CVE). The hazard ratio (HR) for a CVE given positive CMV-serology and IL-1RN*2 was 1.07 (95% confidence interval (CI) 0.32–3.72) in the fully adjusted model compared to seronegative CMV patients not carrying the IL-1RN*2 allele. In this prospective cohort study involving 300 patients with angiographically defined CAD at baseline, homozygousity for allele 2 of the IL-1 RA and seropositivity to CMV alone and in combination were not associated with an increased risk for cardiovascular events during follow-up; in addition, combination of the CMV-seropositivity and IL-1RN*2 allele were not associated with a proinflammatory response

Conclusion

Our study suggests that seropositivity to CMV and IL-1RA*2 genotype alone or in combination might not be a strong risk factor for recurrent cardiovascular events in patients with manifest CAD, and is not associated with levels of established inflammatory markers.

Atherosclerosis and innate immune signaling

Atherosclerosis, the leading cause of death in developed countries, is characterized by chronic inflammation in the artery wall. It has been appreciated for decades that this disease is linked to hypercholesterolemia and the accumulation of macrophages in the artery wall, yet the exact mechanisms underlying this inflammatory process remain unclear. The role of innate and adaptive immune responses in the pathogenesis of atherosclerosis has been an area of intense study. It now appears that activation of innate immune signaling pathways designed to protect us from microbes may be responsible for initiating and feeding the chronic inflammatory cascade that characterizes this disease. In this review, we discuss the recent identification of Toll-like receptors and their downstream signaling pathways as critical contributors to atherosclerosis. Unraveling the contribution of individual Toll-like receptors and identifying the ligands that activate these pathways will be a central focus of atherosclerosis research in the next few years. The involvement of these pathways in atherogenesis will not only open up new avenues of investigation, but it also provides new targets for therapeutic manipulation that could ameliorate the atherosclerotic inflammatory response directly.

Blood coagulation and the risk of atherothrombosis: a complex relationship

The principles of Virchov's triad appear to be operational in atherothrombosis or arterial thrombosis: local flow changes and particularly vacular wall damage are the main pathophysiological elements. Furthermore, alterations in arterial blood composition are also involved although the specific role and importance of blood coagulation is an ongoing matter of debate. In this review we provide support for the hypothesis that activated blood coagulation is an essential determinant of the risk of atherothrombotic complications. We distinguish two phases in atherosclerosis: In the first phase, atherosclerosis develops under influence of "classical" risk factors, i.e. both genetic and acquired forces. While fibrinogen/fibrin molecules participate in early plaque lesions, increased activity of systemic coagulation is of no major influence on the risk of arterial thrombosis, except in rare cases where a number of specific procoagulant forces collide. Despite the presence of tissue factor – factor VII complex it is unlikely that all fibrin in the atherosclerotic plaque is the direct result from local clotting activity. The dominant effect of coagulation in this phase is anticoagulant, i.e. thrombin enhances protein C activation through its binding to endothelial thrombomodulin.

The second phase is characterized by advancing atherosclerosis, with greater impact of inflammation as indicated by an elevated level of plasma C-reactive protein, the result of increased production influenced by interleukin-6. Inflammation overwhelms protective anticoagulant forces, which in itself may have become less efficient due to down regulation of thrombomodulin and endothelial cell protein C receptor (EPCR) expression. In this phase, the inflammatory drive leads to recurrent induction of tissue factor and assembly of catalytic complexes on aggregated cells and on microparticles, maintaining a certain level of thrombin production and fibrin formation. In advanced atherosclerosis systemic and vascular wall driven coagulation becomes more important and elevated levels of D-dimer fragments should be interpreted as markers of this hypercoagulability.

Epidemiology of Helicobacter pylori infection

This review summarizes key results of epidemiologic studies published in peer-reviewed journals between April 2003 and March 2004. The prevalence of H. pylori infection continues to vary strongly between developing countries and developed countries, and according to ethnicity, place of birth and socioeconomic factors among people living in the same country. Intrafamilial spread appears to play a central role in transmission of the infection in both developing and developed countries. The role of H. pylori infection in development of noncardia gastric cancer appears to be even much stronger than previously assumed, whereas the lack of an association with cardia cancer and an inverse association with adenocarcinoma of the esophagus could be confirmed. Suggestions for an inverse association of the infection with atopic diseases have recently received further support, whereas evidence concerning the role of the infection (or its eradication) in GERD and a large variety of other extragastric diseases, including cardiovascular disease, remains inconclusive.