Increased frequency of HLA-A*02 in patients with atherosclerosis is associated with VZV seropositivity

BACKGROUND

HLA molecules are inherited key molecules in the immune inflammation and specific responses to environmental pathogens. We investigated the association of HLA-A alleles with Varicella zoster virus (VZV) seropositivity in patients with atherosclerosis (AS).

MATERIALS AND METHODS

Plasma Anti-VZV IgG and molecular HLA type were detected in 203 (100 AS⁺ and 103 AS^-) individuals.

RESULTS

Of 100 AS⁺ individuals, 66 were anti-VZV⁺ and 34 were anti-VZV^-. Of 103 age/sex-matched AS^- individuals, 59 were anti-VZV⁺ and 44 were anti-VZV^-. Anti-VZV-IgG in AS⁺ cases was higher than AS^- controls (p = .034). The mean anti-VZV IgG in HLA-A*02⁺AS⁺ individuals was higher than HLA-A*02⁺AS^- controls (p < .001). HLA-A*02 was associated with VZV-seropositivity (p = .01) in AS⁺ patients. A higher frequency of HLA-A*02-allele in AS⁺ patients compared to AS^- controls (p = .015) and an accumulation of HLA-A*02-allele in AS⁺ anti-VZV⁺ group (33.3%, p = .004) was observed.

CONCLUSIONS

HLA-A alleles and immune responses to VZV are associated with clinical atherosclerosis.

The impact of atherosclerotic cardiovascular disease, dyslipidaemia and lipid lowering therapy on Coronavirus disease 2019 outcomes: an examination of the available evidence

PURPOSE OF REVIEW

Coronavirus Disease 2019 (COVID19) has caused significant global morbidity and mortality, especially in persons with underlying cardiovascular disease. There have been concerns that lipid-lowering therapy (LLT) increases angiotensin-converting enzyme 2 levels. Conversely, pleiotropic effects of statins can theoretically protect against severe COVID19 infection, supporting evidence from other respiratory illnesses in which statin use probably confers benefit.

RECENT FINDINGS

There is an abundance of studies that show that statins are safe and potentially protect against severe COVID19 infection (critical illness and death), even when adjustment for potential confounders is undertaken. However, the evidence is limited to retrospective cohorts. The benefit for patients with diabetes is less clear. There is a paucity of evidence for other LLT agents. Available clinical guidelines recommend the ongoing use of LLT in patients with COVID19 (unless specifically contra-indicated) and the data from available studies support these.

SUMMARY

In patients with COVID19 infection, LLT should be continued. However, the current findings need substantiating in larger prospective clinical studies with specific examination of the possible mechanisms by which LLT confers benefit from COVID19.

Extracellular Vesicles: Versatile Nanomediators, Potential Biomarkers and Therapeutic Agents in Atherosclerosis and COVID-19-Related Thrombosis

Cells convey information among one another. One instrument employed to transmit data and constituents to specific (target) cells is extracellular vesicles (EVs). They originate from a variety of cells (endothelial, immune cells, platelets, mesenchymal stromal cells, etc.), and consequently, their surface characteristics and cargo vary according to the paternal cell. The cargo could be DNA, mRNA, microRNA, receptors, metabolites, cytoplasmic proteins, or pathological molecules, as a function of which EVs exert different effects upon endocytosis in recipient cells. Recently, EVs have become important participants in a variety of pathologies, including atherogenesis and coronavirus disease 2019 (COVID-19)-associated thrombosis. Herein, we summarize recent advances and some of our own results on the role of EVs in atherosclerotic cardiovascular diseases, and discuss their potential to function as signaling mediators, biomarkers and therapeutic agents. Since COVID-19 patients have a high rate of thrombotic events, a special section of the review is dedicated to the mechanism of thrombosis and the possible therapeutic potential of EVs in COVID-19-related thrombosis. Yet, EV mechanisms and their role in the transfer of information between cells in normal and pathological conditions remain to be explored.

Potential mechanisms of cerebrovascular diseases in COVID-19 patients

Since the outbreak of coronavirus disease 2019 (COVID-19) in 2019, it is gaining worldwide attention at the moment. Apart from respiratory manifestations, neurological dysfunction in COVID-19 patients, especially the occurrence of cerebrovascular diseases (CVD), has been intensively investigated. In this review, the effects of COVID-19 infection on CVD were summarized as follows: (I) angiotensin-converting enzyme 2 (ACE2) may be involved in the attack on vascular endothelial cells by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), leading to endothelial damage and increased subintimal inflammation, which are followed by hemorrhage or thrombosis; (II) SARS-CoV-2 could alter the expression/activity of ACE2, consequently resulting in the disruption of renin-angiotensin system which is associated with the occurrence and progression of atherosclerosis; (III) upregulation of neutrophil extracellular traps has been detected in COVID-19 patients, which is closely associated with immunothrombosis; (IV) the inflammatory cascade induced by SARS-CoV-2 often leads to hypercoagulability and promotes the formation and progress of atherosclerosis; (V) antiphospholipid antibodies are also detected in plasma of some severe cases, which aggravate the thrombosis through the formation of immune complexes; (VI) hyperglycemia in COVID-19 patients may trigger CVD by increasing oxidative stress and blood viscosity; (VII) the COVID-19 outbreak is a global emergency and causes psychological stress, which could be a potential risk factor of CVD as coagulation, and fibrinolysis may be affected. In this review, we aimed to further our understanding of CVD-associated COVID-19 infection, which could improve the therapeutic outcomes of patients. Personalized treatments should be offered to COVID-19 patients at greater risk for stroke in future clinical practice.

Lipids, biomarkers, and subclinical atherosclerosis in treatment-naive HIV patients starting or not starting antiretroviral therapy: Comparison with a healthy control group in a 2-year prospective study

Objective

To assess the effect of HIV infection and combined antiretroviral therapy (c-ART) on various proatherogenic biomarkers and lipids and to investigate their relationship with subclinical atherosclerosis in a cohort of treatment-naive HIV-infected patients.

Methods

We performed a prospective, comparative, multicenter study of 2 groups of treatment-naive HIV-infected patients (group A, CD4>500 cells/μL, not starting c-ART; and group B, CD4<500 cells/μL, starting c-ART at baseline) and a healthy control group. Laboratory analyses and carotid ultrasound were performed at baseline and at months 12 and 24. The parameters measured were low-density lipoprotein (LDL) particle phenotype, lipoprotein-associated phospholipase A2 (Lp-PLA2), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), sCD14, sCD163, monocyte chemoattractant protein-1(MCP-1), and asymmetric dimethylarginine (ADMA). A linear mixed model based on patient clusters was used to assess differences in biomarkers between the study groups and over time.

Results

The study population comprised 62 HIV-infected patients (group A, n = 31; group B, n = 31) and 22 controls. Age was 37 (30–43) years, and 81% were men. At baseline, the HIV-infected patients had a worse LDL particle phenotype and higher plasma concentration of sCD14, sCD163, hs-CRP, and LDL-Lp-PLA2 than the controls. At month 12, there was an increase in total cholesterol (p = 0.002), HDL-c (p = 0.003), and Apo A-I (p = 0.049) and a decrease in sCD14 (p = <0.001) and sCD163 (p<0.001), although only in group B. LDL particle size increased in group B at month 24 (p = 0.038). No changes were observed in group A or in the healthy controls. Common carotid intima-media thickness increased in HIV-infected patients at month 24 (Group A p = 0.053; group B p = 0.048). Plasma levels of sCD14, sCD163, and hs-CRP correlated with lipid values.

Conclusions

In treatment-naive HIV-infected patients, initiation of c-ART was associated with an improvement in LDL particle phenotype and inflammatory/immune biomarkers, reaching values similar to those of the controls. HIV infection was associated with progression of carotid intima-media thickness.

Porphyromonas gingivalis-Induced MIF Regulates Intercellular Adhesion Molecule-1 Expression in EA.hy926 Cells and Monocyte-Endothelial Cell Adhesion Through the Receptors CD74 and CXCR4

Porphyromonas gingivalis (P. gingivalis) is an important pathogen that contributes to periodontal disease and causes infections that promote the progression of atherosclerosis. Our previous studies showed that macrophage migration inhibitory factor (MIF) facilitates monocyte adhesion to endothelial cells by regulating the expression of intercellular adhesion molecule-1 (ICAM-1) in P. gingivalis-infected endothelial cells. However, the detailed pathological role of MIF has yet to be elucidated in this context. To explore the functional receptor(s) of MIF that underlie its participation in the pathogenesis of atherosclerosis, we investigated the expression of the chemokine receptors CD74 and CXCR4 in endothelial cells, both of which were shown to be involved in the adhesion of monocytes to endothelial cells pretreated with P. gingivalis. Furthermore, the formation of a MIF, CD74, and CXCR4 ligand-receptor complex was revealed by our immunofluorescence staining and coimmunoprecipitation results. By interacting with the CD74/CXCR4 receptor complex, MIF may act as a crucial regulator of monocyte-endothelial cell adhesion and promote the atherosclerotic plaque formation induced by P. gingivalis.

Influenza virus and atherosclerosis

Influenza viruses infect the upper respiratory system, causing usually a self-limited disease with mild respiratory symptoms. Acute lung injury, pulmonary microvascular leakage and cardiovascular collapse may occur in severe cases, usually in the elderly or in immunocompromised patients. Acute lung injury is a syndrome associated with pulmonary oedema, hypoxaemia and respiratory failure. Influenza virus primarily binds to the epithelium, interfering with the epithelial sodium channel function. However, the main clinical devastating effects are caused by endothelial dysfunction, thought to be the main mechanism leading to pulmonary oedema, respiratory failure and cardiovascular collapse. A significant association was found between influenza infection and acute myocardial infarction (AMI). The incidence of admission due to AMI during an acute viral infection was six times as high during the 7 days after laboratory confirmation of influenza infection as during the control interval (10-fold in influenza B, 5-fold in influenza A, 3.5-fold in respiratory syncytial virus and 2.7-fold for all other viruses). Our review will focus on the mechanisms responsible for endothelial dysfunction during influenza infection leading to cardiovascular collapse and death.

Chronic hepatitis C, atherosclerosis and cardiovascular disease: What impact of direct-acting antiviral treatments?

Hepatitis C virus (HCV) infection is associated with extrahepatic manifestations, among these there is an increased risk of atherosclerosis and cardiovascular disease as well as an increased cardiovascular mortality. Several direct and indirect HCV pro-atherogenic mechanisms have been proposed. HCV lives and replicates within carotid plaques, promoting a local environment of pro-atherogenic factors. In addition, it causes conditions such as insulin resistance, diabetes, hepatic steatosis, cryoglobulinemia and endotoxinemia that are associated with the development of atherosclerosis and cardiovascular disease. Therapeutic regimens based on direct-acting antiviral agents (DAA) are currently available with high efficacy in HCV clearance and improvement of liver disease, but does HCV eradication also improve atherosclerosis and the risk of cardiovascular disease? Recently, a multi-center study has shown that elimination of HCV improves carotid atherosclerosis. Two studies have shown that DAA treatments significantly reduce the risk of cardiovascular events. Several studies have assessed the impact of HCV clearance on pro-atherosclerosis metabolic conditions showing improvement in cardiovascular risk biomarkers, disappearance or improvement of insulin resistance, reduction of risk of developing diabetes and improvement of glycemic control. There are also evidences that HCV clearance promotes the recovery of cytokines and inflammatory markers associated with atherosclerosis and the disappearance of cryoglobulinemia. Available data show that clearance of HCV by DAAs is associated with an improvement in atherosclerosis and metabolic and immunological conditions that promote the development of cardiovascular disease. However, the data are not sufficient to allow definitive conclusions and further studies will be needed to definitively clarify the impact of HCV clearance on atherosclerosis and cardiovascular disease.

Cardiovascular disease risk prediction by the American College of Cardiology (ACC)/American Heart Association (AHA) Atherosclerotic Cardiovascular Disease (ASCVD) risk score among HIV-infected patients in sub-Saharan Africa

OBJECTIVES

HIV-infected patients are at increased risk for cardiovascular disease (CVD). However, general population CVD risk prediction equations that identify HIV-infected patients at elevated risk have not been widely assessed in sub-Saharan African (SSA).

METHODS

HIV-infected adults from 30-50 years of age with documented viral suppression were enrolled into a cross-sectional study in Gaborone, Botswana. Participants were screened for CVD risk factors. Bilateral carotid intima-media thickness (cIMT) was measured and 10-year predicted risk of cardiovascular disease was calculated using the Pooled Cohorts Equation for atherosclerotic CVD (ASCVD) and the 2008 Framingham Risk Score (FRS) (National Cholesterol Education Program III-NCEP III). ASCVD ≥7.5%, FRS ≥10%, and cIMT≥75th percentile were considered elevated risk for CVD. Agreement in classification of participants as high-risk for CVD by cIMT and FRS or ASCVD risk score was assessed using McNemar`s Test. The optimal cIMT cut off-point that matched ASCVD predicted risk of ≥7.5% was assessed using Youden's J index.

RESULTS

Among 208 HIV-infected patients (female: 55%, mean age 38 years), 78 (38%) met criteria for ASCVD calculation versus 130 (62%) who did not meet the criteria. ASCVD classified more participants as having elevated CVD risk than FRS (14.1% versus 2.6%, McNemar's exact test p = 0.01), while also classifying similar proportion of participants as having elevated CVD like cIMT (14.1% versus 19.2%, McNemar's exact test p = 0.34). Youden's J calculated the optimal cut point at the 81st percentile for cIMT to correspond to an ASCVD score ≥7.5% (sensitivity = 72.7% and specificity = 88.1% with area under the curve for the receiver operating characteristic [AUC] of 0.82, 95% Mann-Whitney CI: 0.66-0.99).

CONCLUSION

While the ASCVD risk score classified more patients at elevated CVD risk than FRS, ASCVD score classified similar proportion of patients as high risk when compared with established subclinical atherosclerosis. However, potential CVD risk category misclassification by established equations such as ASCVD may still exist among HIV-infected patients; hence there is still a need for development of a CVD risk prediction equation tailored to HIV-infected patients in SSA.

Murine Norovirus Infection Variably Alters Atherosclerosis in Mice Lacking Apolipoprotein E

Macrophages play a key role in the development of atherosclerosis. Murine noroviruses (MNV) are highly prevalent in research mouse colonies and infect macrophages and dendritic cells. Our laboratory found that MNV4 infection in mice lacking the LDL receptor alters the development of atherosclerosis, potentially confounding research outcomes. Therefore, we investigated whether MNV4 likewise altered atherosclerosis in ApoE(-/-) mice. In the presence of oxidized LDL, MNV4 infection of ApoE(-/-) bone marrow-derived macrophages increased the gene expression of the inflammatory markers inducible nitric oxide synthase, monocyte chemoattractant protein 1, and IL6. In addition, proteins involved in cholesterol transport were altered in MNV4-infected ApoE -/- bone marrow-derived macrophages and consisted of increased CD36 and decreased ATP-binding cassette transporter A1. MNV4 infection of ApoE(-/-) mice at 12 wk of age (during the development of atherosclerosis) had a variable effect on atherosclerotic lesion size. In one study, MNV4 significantly increased atherosclerotic plaque area whereas in a second study, no effect was observed. Compared with controls, MNV4-infected mice had higher circulating Ly6C-positive monocytes, and viral RNA was detected in the aortas of some mice, suggesting potential mechanisms by which MNV4 alters disease progression. Plaque size did not differ when ApoE -/- mice were infected at 4 wk of age (early during disease development) or in ApoE -/- mice maintained on a high-fat, high-cholesterol diet. Therefore, these data show that MNV4 has the potential to exert a variable and unpredictable effect on atherosclerosis in ApoE(-/-) mice. We therefore propose that performing experiments in MNV-free mouse colonies is warranted.

Current Efavirenz (EFV) or ritonavir-boosted lopinavir (LPV/r) use correlates with elevate markers of atherosclerosis in HIV-infected subjects in Addis Ababa, Ethiopia

BACKGROUND

HIV patients on antiretroviral therapy have shown elevated incidence of dyslipidemia, lipodystrophy, and cardiovascular disease (CVD). Most studies, however, focus on cohorts from developed countries, with less data available for these co-morbidities in Ethiopia and sub-Saharan Africa.

METHODS

Adult HIV-negative (n = 36), treatment naïve (n = 51), efavirenz (EFV)-treated (n = 91), nevirapine (NVP)-treated (n = 95), or ritonavir-boosted lopinavir (LPV/r)-treated (n=44) subjects were recruited from Black Lion Hospital in Addis Ababa, Ethiopia. Aortic pressure, augmentation pressure, and pulse wave velocity (PWV) were measured via applanation tonometry and carotid intima-media thickness (cIMT) and carotid arterial stiffness, and brachial artery flow-mediated dilation (FMD) were measured via non-invasive ultrasound. Body mass index, waist-to-hip circumference ratio (WHR), skinfold thickness, and self-reported fat redistribution were used to quantify lipodystrophy. CD4+ cell count, plasma HIV RNA levels, fasting glucose, total-, HDL-, and LDL-cholesterol, triglycerides, hsCRP, sVCAM-1, sICAM-1, leptin and complete blood count were measured.

RESULTS

PWV and normalized cIMT were elevate and FMD impaired in EFV- and LPV/r-treated subjects compared to NVP-treated subjects; normalized cIMT was also elevated and FMD impaired in the EFV- and LPV/r-treated subjects compared to treatment-naïve subjects. cIMT was not statistically different across groups. Treated subjects exhibited elevated markers of dyslipidemia, inflammation, and lipodystrophy. PWV was associated with age, current EFV and LPV/r used, heart rate, blood pressure, triglycerides, LDL, and hsCRP, FMD with age, HIV duration, WHR, and glucose, and cIMT with age, current EFV use, skinfold thickness, and blood pressure.

CONCLUSIONS

Current EFV- or LPV/r-treatment, but not NVP-treatment, correlated with elevated markers of atherosclerosis, which may involve mechanisms distinct from traditional risk factors.

Effects of murine norovirus on atherosclerosis in ldlr(-/-) mice depends on the timing of infection

We previously reported that murine norovirus (MNV), a virus prevalent in United States research institutions, increased atherosclerotic lesion size in Ldlr(-/-) mice when the mice were infected 8 wk after feeding an atherogenic diet. To determine whether the timing of MNV infection relative to atherosclerosis development altered the disease phenotype and to examine potential mechanisms by which MNV influences the disease process, we fed Ldlr(-/-) mice an atherogenic diet for 16 wk. Three days after initiating the atherogenic diet, half of the mice received MNV4 and the other half vehicle only (clarified cell-culture lysate; controls). Both groups of mice developed large aortic sinus lesions (control compared with MNV4: 133 ± 8 × 10³ μm² compared with 140 ± 7 × 10³ μm²) that were not significantly different in size. Because the timing of MNV infection relative to atherosclerosis development and hypercholesterolemia differed between our previous and the current studies, we examined whether hypercholesterolemia altered MNV4-induced changes in bone-marrow-derived macrophages. MNV4 infection increased the potential of macrophages to take up and store cholesterol by increasing CD36 expression while suppressing the ABCA1 transporter. Thus, the effects of MNV4 infection on atherosclerotic lesion size appear to be dependent on the timing of the infection: MNV4 infection promotes only established lesions. This effect may be due to MNV4's ability to increase cholesterol uptake and decrease efflux by regulating CD36 and ABCA1 protein expression.

Extrahepatic manifestations of HCV

The hepatic consequences of an infection with the hepatitis C virus (HCV) are well recognised, but extrahepatic manifestations of HCV may be just as severe. Here we have reviewed various extrahepatic manifestations of HCV such as mixed cryoglobulinemia, lymphoma, metabolic features and neurologic consequences and we discuss pathogenesis and management of these clinical problems. We concluded with important aspects of therapy with novel anti-HCV agents and its effects on extrahepatic manifestations.

Is hepatitis C associated with atherosclerotic burden? A systematic review and meta-analysis

BACKGROUND AND AIMS

Increasing evidence demonstrates that hepatitis C virus (HCV) infection is associated with atherosclerosis. However, there are contrasting findings in several studies that the atherosclerotic burden is not associated with HCV infections. Therefore, we performed a meta-analysis to clarify if HCV infection is associated with atherosclerosis compared to non-infected people.

METHODS

Standard guidelines for performance of meta-analysis were followed.

RESULTS

A thorough database search performed by two independent investigators identified 14 eligible studies for analysis. The data from 11 studies were synthesized to report unadjusted odds ratios (ORs) for carotid atherosclerosis; the pooled unadjusted OR (95% confidence interval (CI)) was 1.65 (1.21, 2.09). By synthesizing the data from 8 studies to report adjusted ORs for carotid atherosclerosis the pooled multi-confounder adjusted OR (95% CI) was 1.76 (1.20, 2.32). However, the numbers of studies on coronary or femoral atherosclerosis were limited and not enough for analysis.

CONCLUSIONS

Our meta-analysis indicates that HCV infection is associated with carotid atherosclerosis independent of classical risk factors. Therefore, we would recommend for HCV infected patients to be counseled on their risk for carotid atherosclerosis.

Cardiovascular disease in HIV: traditional and nontraditional risk factors

A new paradigm for atherogenesis in HIV infection is emerging, in which viral replication and microbial translocation result in ongoing T-cell and monocyte activation, with persistent inflammation leading to the development of atypical, high-risk morphology plaques. These plaques, characterized by low attenuation and positive remodeling, can be found even among HIV-infected patients who are at low risk for cardiovascular disease based on traditional risk factors. Prevention of cardiovascular events in HIV infection requires modulation of traditional risk factors and is also likely to require effective antiinflammatory treatment strategies. Statins, which are traditionally used to treat dyslipidemia, have also been shown to exert antiinflammatory effects associated with clinical benefit and may be useful to treat and prevent cardiovascular disease in HIV-infected patients. However, large-scale studies of statins in the context of HIV infection must be conducted. This article summarizes a presentation by Steven K. Grinspoon, MD, at the IAS-USA continuing education program held in Chicago, Illinois, in May 2014.

Hepatitis C virus infection and coronary artery disease risk: a systematic review of the literature

BACKGROUND AND AIMS

While hepatitis C virus (HCV) infection has been implicated in increasing the risk of coronary artery disease (CAD), conflicting reports exist regarding this association. We performed a systematic review to further investigate this association.

METHODS

We conducted a PubMed search of original research articles from January 1, 1995 to June 30, 2013 to identify case-control and cohort studies evaluating the association between HCV and CAD using keyword terms ["hepatitis c" or "HCV"] and ["coronary artery disease" or "heart disease" or "atherosclerosis."] The primary CAD-related endpoints included myocardial infarction, congestive heart failure, need for coronary artery bypass grafting, or transluminal percutaneous coronary angioplasty. Binary outcomes are reported as odds ratios (OR) with 95 % confidence interval (CI).

RESULTS

We identified five studies (four cohort studies and one case-control study) that met our inclusion criteria. A significant association between HCV and CAD was demonstrated in one cohort study (adjusted HR 1.27; 95 % CI 1.22-1.31). One cohort study demonstrated a decreased risk of CAD associated with HCV (adjusted OR 0.74; 95 % CI 0.71-0.76). The remaining studies did not find a significant association between HCV and risk of CAD.

CONCLUSIONS

The current systematic review demonstrates that the association between HCV and CAD remains unclear. We need more large, long-term cohort studies with clear definitions of patient population and endpoints to better ascertain the association between HCV and CAD.

Pathogenesis and significance of hepatitis C virus steatosis: An update on survival strategy of a successful pathogen

Hepatitis C virus (HCV) is a successful pathogen on the grounds that it exploits its host’s metabolism to build up viral particles; moreover it favours its own survival by inducing chronic disease and the development of specific anatomic changes in the infected organ. Steatosis, therefore, is associated with HCV infection by necessity rather than by chance alone. Approximately 6% of HCV patients have steatohepatitis. Interestingly, HCV steatosis occurs in the setting of multiple metabolic abnormalities (hyperuricemia, reversible hypocholesterolemia, insulin resistance, arterial hypertension and expansion of visceral adipose tissue) collectively referred to as “hepatitis C-associated dysmetabolic syndrome” (HCADS). General, nonalcoholic fatty liver disease (NAFLD)-like, mechanisms of steatogenesis (including increased availability of lipogenic substrates and de novo lipogenesis; decreased oxidation of fatty substrates and export of fatty substrates) are shared by all HCV genotypes. However, genotype 3 seemingly amplifies such steatogenic molecular mechanisms reported to occur in NAFLD via more profound changes in microsomal triglyceride transfer protein; peroxisome proliferator-activated receptor alpha; sterol regulatory element-binding proteins and phosphatase and tensin homologue. HCV steatosis has a remarkable clinical impact in as much as it is an acknowledged risk factor for accelerated fibrogenesis; for impaired treatment response to interferon and ribavirin; and development of hepatocellular carcinoma. Recent data, moreover, suggest that HCV-steatosis contributes to premature atherogenesis via both direct and indirect mechanisms. In conclusion, HCV steatosis fulfills all expected requirements necessary to perpetuate the HCV life cycle. A better understanding of the physiology of HCADS will likely result in a more successful handling of disease with improved antiviral success rates.

Chronic hepatitis C virus infection and atherosclerosis: Clinical impact and mechanisms

Hepatitis C virus (HCV) infection represents a major health issue worldwide due to its burden of chronic liver disease and extrahepatic manifestations including cardiovascular diseases, which are associated with excess mortality. Analysis of published studies supports the view that HCV infection should be considered a risk factor for the development of carotid atherosclerosis, heart failure and stroke. In contrast, findings from studies addressing coronary artery disease and HCV have yielded conflicting results. Therefore, meta-analytic reviews and prospective studies are warranted. The pathogenic mechanisms connecting HCV infection, chronic liver disease, and atherogenesis are not completely understood. However, it has been hypothesized that HCV may promote atherogenesis and its complications through several direct and indirect biological mechanisms involving HCV colonization and replication within arterial walls, liver steatosis and fibrosis, enhanced and imbalanced secretion of inflammatory cytokines, oxidative stress, endotoxemia, mixed cryoglobulinemia, perturbed cellular and humoral immunity, hyperhomocysteinemia, hypo-adiponectinaemia, insulin resistance, type 2 diabetes and other components of the metabolic syndrome. Understanding these complex mechanisms is of fundamental importance for the development of novel therapeutic approaches to prevent and to treat vascular complications in patients with chronic HCV infection. Currently, it seems that HCV clearance by interferon and ribavirin treatment significantly reduces non-liver-related mortality; moreover, interferon-based treatment appears to decrease the risk of ischemic stroke.

Human cytomegalovirus-platelet interaction triggers toll-like receptor 2-dependent proinflammatory and proangiogenic responses

OBJECTIVE

Human cytomegalovirus (HCMV) is a widespread pathogen that correlates with various clinical complications, including atherosclerosis. HCMV is released into the circulation during primary infection and periodic viral reactivation, allowing virus-platelet interactions. Platelets are important in the onset and development of atherosclerosis, but the consequences of platelet-HCMV interactions are unclear.

APPROACH AND RESULTS

We studied the effects of HCMV-platelet interactions in blood from healthy donors using the purified clinical HCMV isolate VR1814. We demonstrated that HCMV bound to a Toll-like receptor (TLR) 2-positive platelet subpopulation, which resulted in signal transduction, degranulation, and release of proinflammatory CD40L and interleukin-1β and proangiogenic vascular endothelial-derived growth factor. In mice, murine CMV activated wild-type but not TLR2-deficient platelets. However, supernatant from murine CMV-stimulated wild-type platelets also activated TLR2-deficient platelets, indicating that activated platelets generated soluble mediators that triggered further platelet activation, independent of TLR2 expression. Inhibitor studies, using ADP receptor antagonists and apyrase, revealed that ADP release is important to trigger secondary platelet activation in response to HCMV. HCMV-activated platelets rapidly bound to and activated neutrophils, supporting their adhesion and transmigration through endothelial monolayers. In an in vivo model, murine CMV induced systemic upregulation of platelet-leukocyte aggregates and plasma vascular endothelial-derived growth factor in mice and showed a tendency to enhance neutrophil extravasation in a TLR2-dependent fashion.

CONCLUSIONS

HCMV is a well-adapted pathogen that does not induce immediate thrombotic events. However, HCMV-platelet interactions lead to proinflammatory and proangiogenic responses, which exacerbate tissue damage and contribute to atherogenesis. Therefore, platelets might contribute to the effects of HCMV in accelerating atherosclerosis.

The role of infection and immunity in atherosclerosis

Cardiovascular diseases account for 20% of deaths worldwide, rising to 50% in developed countries. Current understanding of atherosclerosis derives from a combination of research in animals and cell cultures, analysis of human lesions, clinical investigations of patients with acute coronary syndromes and epidemiological studies of coronary artery disease. By measuring serologic titers in the serum of patients after cardiovascular events, it was observed that the greater the infectious exposure of a patient, the larger the atherosclerotic lesion extension. In addition, gene targeting or pharmacological inhibition of certain cytokines aggravates atherosclerosis in animal experiments. Other animal experiments have succeeded in proving that B cells play a protective role in atherosclerosis through induced immunity against oxidized low-density lipoprotein and other epitopes. Molecular mimicry might respond to the question of how infection may trigger vulnerability in previously stable atherosclerotic lesions. The FLU Vaccination Acute Coronary Syndromes trial enhanced the debate on atherosclerosis prevention by the application of antiflu vaccine. So far, antibiotics have failed to reduce cardiovascular risk, as recent trials could not demonstrate a statistically significant risk reduction. Having assumed atherosclerosis to be an inflammatory disease, the WHO considered the possible role of secondary prevention with antiflu vaccine.

The prospective association of Chlamydia pneumoniae and four other pathogens with development of coronary artery calcium: the multi-ethnic study of atherosclerosis (MESA)

OBJECTIVE

Previous basic and cross-sectional studies obtained conflicting results regarding the association of pathogens with coronary artery calcium (CAC). The aim of this study is to prospectively evaluate this association in a population-based cohort.

METHODS

We examined 5744 individuals aged 45-84 years at baseline (2000-02) who underwent repeated CAC assessment on average 2.4 years later (a half at visit 2 [2002-04] and the other half at visit 3 [2004-05]). CAC incidence was defined as newly detectable CAC at follow-up (475 cases of 2942 participants). CAC progression was defined as annualized change in CAC Agatston score ≥10 units/year if baseline CAC score >0 to <100 or ≥10%/year if baseline score ≥ 100 (1537 cases of 2802 participants). Seropositivity was assessed in the entire cohort for Chlamydia pneumoniae and in a random sample (n = 873) for Helicobacter pylori, cytomegalovirus, herpes simplex virus, and hepatitis A virus.

RESULTS

Seropositivity to C. pneumoniae was not significantly associated with CAC incidence (odds ratio [OR] 1.11 [95% CI, 0.88-1.39], P = 0.371) or progression (1.14 [0.96-1.36], P = 0.135) even in unadjusted models. When CAC incidence and progression were combined, we observed significant association with C. pneumoniae seropositivity before adjustment (OR 1.17 [1.03-1.33], P = 0.016) but not in a model adjusting for traditional risk factors (1.04 [0.90-1.19], P = 0.611). The results were consistent across subgroups according to age, sex, and race/ethnicity. None of five pathogens or their accrual was associated with CAC incidence and progression in the subsample.

CONCLUSION

Our prospective study does not support the pathophysiological involvement of these pathogens in CAC development.

Endothelial dysfunction in HIV infection--the role of circulating endothelial cells, microparticles, endothelial progenitor cells and macrophages

Endothelial dysfunction has emerged as one of the major mechanisms involved in the increased cardiovascular disease risk seen in the HIV population. Endothelial progenitor cells, circulating endothelial cells, endothelial microparticles, and platelet microparticles are all now considered as biomarkers of cardiovascular disease risk in otherwise healthy individuals. Preliminary evidence suggests that these biomarkers may similarly predict cardiovascular disease risk in HIV-infected patients, helping to assist in preventive and therapeutic decision making. This review updates the current knowledge and the most recent advances in the pathophysiology of cells and particles involved in atherosclerosis in the HIV setting. The potential usefulness of measuring cardiovascular disease risk biomarkers in HIV-infected individuals to prevent future cardiovascular events is further discussed.

Role of herpes simplex virus-1, cytomegalovirus and Epstein-Barr virus in atherosclerosis

Infectious agents such as herpes viruses may be implicated in the inflammatory atherosclerotic process. The aim of this study was to assess the levels of IgG antibody specific for Herpes simplex virus-1 (HSV-1), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) among patients with atherosclerotic vascular diseases and to examine the relation between the levels of these antibodies and lipid profile, high-sensitive C-reactive protein (hsCRP) in these patients. Seventy five patients [20 with acute coronary artery disease (ACAD), 20 with chronic coronary artery disease (CCAD), 20 with cerebral stroke and 15 with peripheral arterial disease (PAD)] along with 15 healthy individuals as a control group. The studied individuals were subjected to complete history taking, thorough physical examination, and assessment of the blood glucose level, lipid profile, creatine kinase (CK), hsCRP by nephlemetry and virus-specific IgG antibodies by enzyme immunoassay (EIA). Results showed that the levels of cholesterol, triglycerides, LDL-c and hsCRP were significantly higher, while HDL-c was significantly lower among patients compared to that of the controls. A significantly (p<0.05) higher percentage of patients had CMV-specific IgG as compared to the controls. Higher percentage of patients had HSV- and EBV-specific IgG antibodies, however, there was no significant difference between the 2 groups. Individuals who had CMV-specific IgG were more liable to have vascular disease compared to those without (OR=4.10, CI= 1.07-15.75). The levels of CMV- and EBV-specific IgG antibodies were significantly (P<0.01 and < 0.05 respectively) elevated among patients with atherosclerotic vascular diseases when compared to those of the controls. There was no significant correlation between the levels of virus-specific IgG and lipid profile or hsCRP. In conclusion, the level of CMV- and EBV- specific antibodies are elevated among vascular disease patients and the presence of CMV-specific IgG is associated with development of the disease. Serum lipids and hsCRP were increased among the studied patients; however, no significant correlation was detected between antiviral IgG levels and lipid profile or hsCRP.

Is HIV-1 infection associated with endothelial dysfunction in a population of African ancestry in South Africa?

The chronic infection status suffered by HIV-infected individuals promotes chronic arterial inflammation and injury, which leads to dysfunction of the endothelium, atherosclerosis and thrombosis. Although HIV-1 subtype C is prevalent in South Africa and accounts for almost a third of the infections worldwide, this subtype differs genetically from HIV-1 subtype B on which the majority of studies have been done. The objective of this study was to assess whether newly identified, never-treated, HIV-1-infected South African participants showed signs of endothelial dysfunction, accelerated atherosclerosis and increased blood coagulation. We compared 300 newly diagnosed (never antiretroviraltreated) HIV-infected participants to 300 age-, gender-, body mass index- and locality-matched uninfected controls. Levels of high-density lipoprotein cholesterol (HDL-C), triglycerides, interleukin-6 (IL-6), C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), fibrinogen and plasminogen activator inhibitor-1 (PAI-1), and carotid radialis pulse wave velocity (cr-PWV) were determined. The HIV-infected participants showed lower HDL-C and higher IL-6, CRP, ICAM-1 and VCAM-1 levels compared to the uninfected controls. No differences in fibrinogen and PAI-1 levels were detected. A continuous positive trend of increasing age with cr-PWV was detected in the HIV-infected group. Our findings suggest inflammatory injury of the endothelium, pointing to endothelial dysfunction of never-treated HIV-1-infected South Africans of African ancestry. Although no indication of a prothrombotic state could be detected, there was an indication of accelerated vascular aging and probable early atherosclerosis in the older HIV-infected participants.

[Fluvastatin's effect on atherogenesis in apolipoprotein-E knockout mice infected by cytomegalovirus]

OBJECTIVE

The goal of this study was to investigate whether murine cytomegalovirus (MCMV) is able to exacerbate the atherosclerotic process in apolipoprotein E knockout (apoE -/-) mice, and the effect of fluvastatin on the atherogenesis.

METHODS

The apoE-/- mice kept on a west diet were given low dosage of MCMV. At 14,18 and 24 weeks post infection, AS lesion were measured on aorta. The fluvastatin was administered, and AS lesion were measured accordingly above.

RESULTS

We observed that in the chronic phase of the infection, AS lesion area was significantly increased. MCMV gB mRNA was not amplified by real-time PCR from the arterial wall. The IgG antibody level of MCMV in blood plasma and the content of virus DNA in salivary gland were not correlated with AS lesions. After the administration of fluvastatin, there was no significant difference of AS lesions between MCMV infected group and mock-infected group.

CONCLUSION

MCMV may aggravate the AS lesion in apoE -/- mice in the chronic phase of infection, and promote more severe type of AS lesions. But it might not be the direct effects of mechanism of MCMV on the local lesion of AS. Fluvastatin could meliorate the progression of AS after MCMV infection, but this was not accomplished by decreasing MCMV duplication.

Infectious burden and carotid plaque thickness: the northern Manhattan study

BACKGROUND AND PURPOSE

The overall burden of prior infections may contribute to atherosclerosis and stroke risk. We hypothesized that serological evidence of common infections would be associated with carotid plaque thickness in a multiethnic cohort.

METHODS

Antibody titers to 5 common infectious microorganisms (ie, Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpesvirus 1 and 2) were measured among stroke-free community participants and a weighted index of infectious burden was calculated based on Cox models previously derived for the association of each infection with stroke risk. High-resolution carotid duplex Doppler studies were used to assess maximum carotid plaque thickness. Weighted least squares regression was used to measure the association between infectious burden and maximum carotid plaque thickness after adjusting for other risk factors.

RESULTS

Serological results for all 5 infectious organisms were available in 861 participants with maximum carotid plaque thickness measurements available (mean age, 67.2+/-9.6 years). Each individual infection was associated with stroke risk after adjusting for other risk factors. The infectious burden index (n=861) had a mean of 1.00+/-0.35 SD and a median of 1.08. Plaque was present in 52% of participants (mean, 0.90+/-1.04 mm). Infectious burden was associated with maximum carotid plaque thickness (adjusted increase in maximum carotid plaque thickness 0.09 mm; 95% CI, 0.03 to 0.15 mm per SD increase of infectious burden).

CONCLUSIONS

A quantitative weighted index of infectious burden, derived from the magnitude of association of individual infections with stroke, was associated with carotid plaque thickness in this multiethnic cohort. These results lend support to the notion that past or chronic exposure to common infections, perhaps by exacerbating inflammation, contributes to atherosclerosis. Future studies are needed to confirm this hypothesis and to define optimal measures of infectious burden as a vascular risk factor.

[Distribution of cytomegalovirus DNA in vascular tissues and the relationship between virus and atherosclersogenesis]

OBJECTIVE

To explore the distribution of cytomegalovirus (CMV) in vascular tissues and the relationship between virus and atherosclerogenesis after CMV infecting mice.

METHODS

(1) C57 BL/6J Murine model of CMV infection was established by intraperitoneal injection of CMV lethiferous amount. (2) After 12 weeks of CMV infection, the sera, carotids, aorta, hearts and postcaval veins from the mice were collected under euthanasia. The tissues would be used to DNA extraction, PCR and pathological examination. (3) Interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) in serum were measured with ILELISA.

RESULTS

(1) The typical pathologic feature in 2 aorta samples of 6 mice infected by CMV was found and the mice uninfected by CMV did not show any pathologic change. (2) CMV DNA appeared in 6 aorta, 6 postcaval veins, 4 carotids and 4 heart tissues including endocardium, cardiac muscle and coronary artery from the CMV infected mice. CMV DNA was not found in the vascular and heart tissues from 6 mice uninfected by CMV. (3) The ELISA test showed the significant difference (Mann-Witney test of Nonparametric Test, P < 0.05) in serum IL-6 (Median among 25% and 75% percentile: 113.7 pg/ml vs. 49.77 pg/ml) and MCP-1 (Median among 25% and 75% percentile: 128.7 pg/ml vs. 45.36 pg/ml) between CMV infected mice and uninfected mice.

CONCLUSION

Cardiovascular cells are CMV latent reservoir in host body and CMV infection and the cytokines induced by CMV infection probably relate to atherosclerogenesis.

Epstein-Barr virus-encoded dUTPase enhances proinflammatory cytokine production by macrophages in contact with endothelial cells: evidence for depression-induced atherosclerotic risk

Increased levels of proinflammatory cytokines, TNF-alpha and IL-6, predict mortality and morbidity. In cardiovascular disease patients, they are observed in atherosclerotic lesions and serum. Factors behind the increased levels of these cytokines are multifaceted and may include latent herpesviruses, such as Epstein-Barr virus (EBV) that can be reactivated by stress. Previously, we showed that the EBV-encoded deoxyuridine triphosphate nucleotidohydrolase (dUTPase), a protein synthesized in the early phase of virus replication, can induce human monocytes/macrophages to produce TNF-alpha and IL-6. In this study, we modeled the interactions that take place between macrophages and endothelial cells in vivo using human umbilical vein endothelial cells (HUVEC). HUVEC were stimulated by soluble factors induced by EBV dUTPase-treated monocyte-derived macrophages (MDM) that resulted in the upregulation of VCAM-1 and ICAM-1. These changes were related to MDM production of TNF-alpha following the activation of NF-kappaB. In a previous study, chronically stressed dementia caregivers had elevations in plasma IL-6 levels, a risk for cardiovascular disease. We found a relationship between plasma IL-6 levels and neutralizing antibody titers to EBV dUTPase suggesting that one source of the plasma IL-6 observed in our previous study could be related to the effect of EBV-encoded dUTPase on macrophages. The results suggest that EBV-encoded dUTPase can enhance production of proinflammatory cytokines by monocytes/macrophages in contact with endothelial cells of blood vessels, and may play a role in cardiovascular pathology and chronic inflammation.

Infection and atherosclerosis. An alternative view on an outdated hypothesis

Already at the beginning of the 20th century, a potential role for microbes in vascular diseases was suggested. However, until the late '70 of that century, not much attention has been paid to this infection hypothesis. Then, predominantly based on the pioneering work of Fabricant et al., evidence for a contributing or even initiating role for microbes in atherosclerosis, as well as other vascular diseases, was accumulating. Also, the seminal paper by Saikku and co-workers, demonstrating serological evidence of an association of Chlamydia pneumoniae, an obligate intracellular respiratory gram-negative bacterium, with chronic coronary heart disease and acute myocardial infarction, significantly boosted the research on the infection hypothesis. Since then, numerous papers have been published demonstrating associations between a large variety of pathogens and atherosclerotic disease. Furthermore, many molecular mechanisms have been suggested by which microbes may affect atherogenesis. Nevertheless, in recent large randomised prospective trials, evaluating the efficacy of antibiotic treatment for the secondary prevention of coronary events, no reduction in the rate of cardiovascular events was observed, thereby seriously challenging the validity of the infection hypothesis. Nevertheless, the large body of supporting evidence, which has accumulate over the past decades, should not be ignored and maybe we should look at the hypothesis, and in particular the mechanisms by which microbes affect the disease, from a different angle.

Detection of human cytomegalovirus in the atherosclerotic cerebral arteries in Han population in China

The association of atherosclerosis (AS) and Human cytomegalovirus (HCMV) infection was studied. AS plays an important role in the brain stroke and HCMV infection is supposed to be involved in the process of atherosclerotic formation. The presence of HCMV DNA and antigens was examined in the internal carotid arteries collected from 35 patients with ischemic stroke and from 20 patients from the control population. All patients belonged to the ethnic Han population in China. Three methods, immunohistochemistry (IHC), hybridization in situ (HIS), and PCR were used to detect the HCMV immediate early (IE) and late (L) antigens as well as viral DNA in vessel walls. Levels of HCMV IE gene/protein were significantly higher in the stroke group than in control group detected by the three methods (IHC 34.3% vs. 10.0%; HIS 40.0% vs. 10.0; PCR 60.0% vs. 30.0%). However, there was no significant difference in the levels of HCMV L gene/protein between these two groups of patients (IHC 11.4% vs. 5.0%; HIS 11.4% vs. 10.0%; PCR 20.0% vs. 20.0%). We concluded that the presence of HCMV IE antigen and HCMV DNA in the vessel wall was associated with the pathological process of AS formation.

Effects of atypical pneumonia agents on progression of atherosclerosis and acute coronary syndrome

BACKGROUND

The aim of this study was to investigate the presence of various atypical pneumonia agents (Chlamydia pneumoniae, cytomegalovirus, Mycoplasma pneumoniae), which are considered to have a role in the ethiopathogenesis of atherosclerosis, in aortic biopsies without macroscopically visible plaque and in internal thoracic artery biopsies.

MATERIAL AND METHODS

Thirty-three patients (group 1), who had undergone coronary bypass operation and 10 non-atherosclerotic patients (group 2), were included in the study. Seventy-six tissue biopsies were taken. Biopsies from the patients in group 1 a were obtained from the atheroma plaque-free aortic tissue and 33 biopsies (group Ib) were obtained from their internal thoracic arteries. Following DNA extraction, nested PCR was used to detect Chlamydia pneumoniae DNA, and real time PCR was used to detect cytomegalovirus and Mycoplasma pneumoniae DNA. Blood parameters (lipid profile, CRP, fibrinogen) of the patients and operation characteristics were recorded.

RESULTS

Chlamydia pneumoniae DNA was detected in 5 of 33 biopsy samples from coronary bypass patients, whereas none of the control patients (group 1b and group 2) were positive for this agent (P = 0.001). Neither CMV nor Mycoplasma pneumoniae was detected in IMA and aortic biopsies of both bypass and control patients. Elevated total cholesterol levels (P = 0.02) and positive CRP (P = 0.001) was found in C. pneumoniae positive patients. Prevalence of acute coronary syndrome was significantly higher in C. pneumoniae detected patients compared (P = 0.00 1).

CONCLUSIONS

Detection of C. pneumoniae DNA in the atheroma free aortic biopsies might indicate that this micro-organism intervened in the progression of atheroma plaque. There was a strong relationship between the detection of this micro-organism in the aortic wall and acute coronary syndrome. The absence of DNA of the corresponding micro-organisms in the IMA wall may show its resistance to infective agents and in turn to atherosclerosis, which is a result of the prevailing endothelial functions of this artery.

Human immunodeficiency virus infection and macrophage cholesterol metabolism

Macrophages play a central role in the pathogenesis of atherosclerosis and are also a host for a number of viruses, most importantly, HIV. Many viruses, including HIV, require cholesterol for their replication and as a structural element. Cholesterol also plays a pivotal role in innate antiviral immune responses. Although impairing innate immune response by increasing cell cholesterol content may be a deliberate strategy used by a pathogen to improve its infectivity, enhancing the risk of atherosclerosis is likely a byproduct. Consistent association between HIV infection and elevated risk of atherosclerosis suggested a connection between virus-induced changes in cholesterol metabolism and atherogenesis, but the mechanisms of such connection have not been identified. We describe in this review various mechanisms enabling viruses to exploit macrophage pathways of cholesterol metabolism, thus diverting cholesterol for a purpose of increasing viral replication and/or for altering innate immune responses. To alter the cellular cholesterol content, viruses "hijack" the pathways responsible for maintaining intracellular cholesterol metabolism. The damage to these pathways by viral infection may result in the inability of macrophages to control cholesterol accumulation and may lead to formation of foam cells, a characteristic feature of atherosclerosis. Further elucidation of the mechanisms connecting viral infection and macrophage cholesterol metabolism may be fruitful for developing approaches to treatment of atherosclerosis and viral diseases.

Chronic Immune Reactivity Against Persisting Microbial Antigen in the Vasculature Exacerbates Atherosclerotic Lesion Formation

Objective— The purpose of this study was to examine the relative contribution of different immunopathological mechanisms during murine cytomegalovirus (MCMV)-mediated acceleration of atheroma formation in apolipoprotein E–deficient (apoE −/− ) mice.

Methods and Results— To distinguish between the effects of systemic activation and cognate immune reactivity against a pathogen-derived persisting antigen in the vasculature, we used hypercholesterolemic transgenic mice constitutively expressing the β-galactosidase (β-gal) transgene in the cardiovascular system (apoE −/− ×SM-LacZ). After infection with β-gal–recombinant MCMV-LacZ, apoE −/− , and apoE −/− ×SM-LacZ mice mounted comparable cellular immune responses against the virus. β-gal–specific CD8 + T cells expanded rapidly and remained detectable for at least 100 days in both mouse strains. However, compared with apoE −/− mice, apoE −/− ×SM-LacZ mice developed drastically accelerated atherosclerosis. Moreover, atherosclerotic lesions in MCMV-LacZ–infected apoE −/− ×SM-LacZ but not apoE −/− mice were associated with pronounced inflammatory infiltrates.

Conclusions— Taken together, our data indicate that chronic immune reactivity against pathogen-derived antigens persisting in the vasculature significantly exacerbates atherogenesis.

Hepatitis B virus seropositivity and the risk of stroke and myocardial infarction

BACKGROUND AND PURPOSE

Conflicting findings on the possible association between hepatitis B virus surface antigen (HBsAg) seropositivity and atherosclerosis have been reported. We examined the association between HBsAg seropositivity and cardiovascular diseases in a cohort of Koreans with a high prevalence of hepatitis B viral infection.

METHODS

Men (N=521 421) aged 30 to 64 years were categorized into 4 groups according to HBsAg seropositivity status and the presence of liver dysfunction were followed up from 1990 to 2001 for both fatal and nonfatal myocardial infarctions (MIs) and strokes. The associations of HBsAg seropositivity with these cardiovascular diseases were examined with a Cox proportional-hazards model.

RESULT

Overall, HBsAg seropositivity was associated with a decreased risk of ischemic stroke and MI and an increased risk of hemorrhagic stroke, with multivariable-adjusted hazard ratios (95% CIs) of 0.79 (0.68, 0.90), 0.74 (0.62, 0.87), and 1.33 (1.15, 1.52), respectively. Risks for stroke and MI were similar between HBsAg-seronegative and HBsAg-seropositive men in the absence of liver dysfunction, whereas men with both HBsAg seropositivity and liver dysfunction had a higher risk of hemorrhagic stroke and lower risks of ischemic stroke and MI compared with HBsAg-seronegative men.

CONCLUSIONS

The association between HBsAg seropositivity and stroke and MI appears to be secondary to the liver dysfunction associated with hepatitis B viral infection. HBsAg seropositivity itself did not appear to play an important role in atherothrombosis through inducing a proinflammatory effect.

Carotid Intima-Media Thickness in HIV-Infected Individuals: Relationship of Premature Atherosclerosis to Neuropsychological Deficits?

BACKGROUND

Intima-media thickness (IMT) measured by extracranial duplex sonography is a surrogate marker for atherosclerosis. It is well known that IMT is greater in HIV patients than in age-matched healthy controls due to HIV- induced endothelial damage and metabolic side-effects of antiretroviral therapy. However, it remains unclear whether atherosclerosis has an additional impact on cognitive function in HIV patients. Therefore, the objective of this study was to investigate the correlation between IMT and neuropsychological deficits in HIV patients.

METHODS

47 HIV patients and 40 age-matched healthy controls were examined by extracranial ultrasound 2 and 3 cm before the flow divider to evaluate differences in IMT. Possible neuropsychological deficits in HIV patients were assessed using a battery of 10 neuropsychological tests. Results of neuropsychological tests and markers of disease severity were correlated with IMT in HIV patients.

RESULTS

IMT was significantly greater in patients than in healthy controls (p < 0.001). However, none of the neuropsychological tests correlated significantly with IMT measurements in HIV patients. There was only a weak correlation between deficits in attention and IMT in HIV patients (r = 0.44; p = 0.005), which was non-significant after correction for multiple comparisons. Markers of disease severity (CD4 cell count, HIV load in plasma, duration of HIV disease) did not correlate with IMT either.

CONCLUSION

IMT was greater in HIV patients compared to age-matched controls but it appears that premature atherosclerosis has no additional impact on the evolution of neuropsychological deficits in HIV patients. IMT did not correlate with the severity of immunodeficiency.

Cytomegalovirus and Proliferative Signals in the Vascular Wall of CABG Patients

OBJECTIVE

To further elucidate the mechanism by which cytomegalovirus (CMV) may promote atherosclerosis, we studied the expression pattern of cellular inflammatory and proliferative signals in the aortic wall of CMV(+) and CMV(-) patients undergoing coronary artery bypass grafting (CABG).

METHODS

Aortic biopsies and blood samples of 68 CABG patients were investigated for CMV-DNA by PCR and IN SITU hybridisation. Expression of pp65 antigen, adhesion molecules (ICAM-1, VCAM-1, E-selectin), growth factors (PDGF-AA, TGF-beta), and the cellular proliferation factor Ki-67 was studied by immunohistochemistry. Logistic regression was used to test the correlation between the presence of CMV, vascular inflammation, and traditional noninflammatory risk factors for atherosclerosis.

RESULTS

CMV-DNA was detected in the aortic tissue of 52 (76%) patients, and was localised predominantly in vascular smooth muscle cells. In CMV(+) patients, the expression of adhesion molecules and growth factors in the aortic endothelium was increased compared with CMV(-) patients. A positive correlation of elevated CRP, the induction of adhesion molecules and growth factors and CMV(+) was found. Female gender, smoking, and hyperlipidaemia were identified as risk factors for CMV(+).

CONCLUSIONS

CMV-DNA in smooth muscle cells induces local growth factor expression as well as endothelial activation, both of which can promote the progression of atherosclerosis. Since traditional atherogenic risk factors increase the likelihood of aortic CMV manifestation, we suggest that CMV plays a crucial role in mediating the progression of atherosclerosis.

Immune activation following cytomegalovirus infection: More important than direct viral effects in cardiovascular disease?

BACKGROUND

Over the last 30 years multiple micro-organisms have been associated with different types of vascular disease, like atherosclerosis, restenosis or transplant arteriosclerosis. Nonetheless, it is still ambiguous which molecular mechanisms are exactly involved in the exacerbating effect of microbes in these disorders.

OBJECTIVES AND STUDY DESIGN

The present review summarizes sero-epidemiological, in vitro and animal data supporting the role of cytomegalovirus, a member of the herpes virus family, in vascular disease. Additionally, various ways by which the virus can potentially affect the disease will be discussed.

RESULTS

Rodent models as well as in vitro studies suggested that CMV might enhance lesion formation in various ways, like augmentation of the oxLDL uptake, altering monocyte adhesion or increasing the production of pro-inflammatory cytokines. Nevertheless, recent data from our lab and others suggest that alternative mechanisms also may contribute to CMV induced. Inspired by this, we will hypothesise alternative mechanisms by which CMV might affect atherosclerosis.

CONCLUSIONS

Although researchers have tried for many years to unravel the tactics by which micro-organisms, like CMV, aggravate atherosclerosis, so far most suggested mechanisms failed to fully explain both experimental and clinical observations. Therefore, new means to elucidate the observed effects are required.

Detection of cytomegalovirus and Helicobacter pylori DNA in arterial walls with grade III atherosclerosis by PCR

It has been suggested that some microorganisms may play a role in the etiology or progression of atherosclerotic plaques. The purpose of this study was to assess for the presence of Helicobacter pylori and cytomegalovirus (CMV) DNA using polymerase chain reaction (PCR) technique in vascular-wall specimens obtained during autopsy. Four to 5 mm long samples from 3 different vascular wall specimens (coronary, carotid and abdominal aortas) of 30 patients (23 male, 7 female) were taken for pathologic and microbiologic investigations during autopsy. H. pylori DNA was found in 48.2% atherosclerotic and 19.6% non-atherosclerotic vascular wall specimens, whereas CMV DNA was found in 37.9% atherosclerotic and 32.7% non-atherosclerotic vascular wall specimens. In terms of CMV DNA detection, no statistically significant differences between the atherosclerotic and non-atherosclerotic groups were present (P > 0.05). However, there was a statistically significant difference between the atherosclerosis and non-atherosclerotic groups in terms of H. pylori DNA in coronary and abdominal aorta arteries (p = 0.016 and p = 0.0029 respectively) but not in carotid arteries (p = 1.00). In conclusion, the correlation between H. pylori and atherosclerosis could be suggested. These finding warrant further investigation regarding the role of H. pylori in atherosclerosis.

Murine cytomegalovirus infection markedly reduces serum MCP-1 levels in MCP-1 transgenic mice

Monocyte chemoattractant protein-1 (MCP-1) is a pro-inflammatory chemokine believed to play a major role in atherogenesis. Injured endothelial cells express MCP-1, which attracts monocytes to the blood vessel wall and leads to the formation of atheromas. Cytomegalovirus infection may also play a role in atherogenesis and accelerates inflammation in tissues that overexpress MCP-1. To examine the relationship of cytomegalovirus infection and MCP-1, we infected MCP-1 transgenic mice with murine cytomegalovirus (MCMV) and collected serum 6 days post-infection to evaluate TH1-related cytokine levels by ELISA. Serum levels of IL-10, IL-12 and IFN-gamma were increased in MCP-1 transgenic mice on day 6 following MCMV infection, while levels of IL-1beta and TNF-alpha were undetectable. However, MCP-1 serum levels were reduced >50% in MCP-1 transgenic mice following MCMV infection compared to uninfected transgenic mice. This effect was not as dramatic when an M33 null MCMV was administered to MCP-1 transgenic mice. The mechanism by which MCMV lowers serum MCP-1 levels is unknown, but this effect may enhance the survival of the virus and thus allow CMV to contribute to the chronic inflammation of atherogenesis.

What's bugging you?

Alzheimer's disease, atherosclerosis, and other diseases of aging might share something with sinus infections and flu. According to preliminary research, all stem from bacterial or viral attacks. Circumstantial evidence points to the lung-attacking bacterium Chlamydia pneumoniae , the herpes simplex I virus, and other germs. Although supporters of the hypothesis have amassed suggestive data, many researchers remain skeptical. However, advocates argue that we might have to accept weaker-than-usual evidence because the diseases kill so many people.

Human cytomegalovirus, endothelial function and atherosclerosis

Human cytomegalovirus (HCMV) serology is linked to several measures of endothelial dysfunction. There is substantial evidence for HCMV having an aetiological role in transplant arterial disease and accumulating evidence for HCMV in the origins of preeclampsia. However, whether HCMV is a clinically significant cause of atherosclerosis in the general, immunocompetent population remains to be seen.

Influenza and atherosclerosis: vaccination for cardiovascular disease prevention

In both animal and human studies, strong prothrombotic and pro-inflammatory effects have been observed after influenza infection. Influenza is an important trigger for acute coronary syndromes, and it has been shown that in the US it may cause up to 90,000 deaths per year simply by triggering fatal myocardial infarctions. Multiple case-control and cohort studies have shown that the influenza vaccine has a marked protective effect against cardiovascular events, decreasing the incidence of these events by 20 - 70% in the settings of primary and secondary prevention. Although influenza vaccination is an extremely cost-effective method of cardiovascular protection and is recommended for all patients with cardiac diseases, it is largely underused in these patients. Therefore, increased efforts should be directed towards educating physicians and patients about the benefits of influenza vaccination in patients with coronary heart disease.

HCMV infection of human vascular smooth muscle cells leads to enhanced expression of functionally intact PDGF beta-receptor

BACKGROUND

Cytomegaloviruses have been shown to promote atherogenesis in animal models. In humans, several epidemiological and clinical studies suggest involvement of the human cytomegalovirus (HCMV) in the development of atherosclerosis. HCMV is suspected to be associated with an enhanced restenosis rate and the occurrence of vasculopathies after solid organ transplantation. However, knowledge about the cellular and molecular bases of these findings is very limited.

METHODS AND RESULTS

Human coronary artery smooth muscle cells (HCASMC) were successfully infected with HCMV in vitro. Infection of HCASMC with all HCMV strains analyzed resulted in a substantial upregulation of the beta-receptor of platelet-derived growth factor (PDGFR-beta) expression as demonstrated by immunohistochemistry, immunofluorescence, FACS, and Western blot analysis. The amount of PDGFR-beta protein present in HCASMC rapidly increased after 12 h of infection and this difference persisted for 72 h post-infection. We showed by quantitative FACS analysis that the extent of PDGFR-beta upregulation differed significantly between the HCMV strains TB40E, Toledo, and AD169. The expression of insulin-like growth factor receptors as well as hepatocyte growth factor receptors, however, was down-modulated in HCMV-infected HCASMC. Most importantly, the HCMV-associated upregulation of PDGFR-beta protein resulted in functionally intact receptors. A significantly higher increase of proliferative activity following stimulation with PDGF-BB was observed in HCMV-infected HCASMC compared to the uninfected control.

CONCLUSIONS

Our data suggest that HCMV directly activates the PDGF system, which could promote atherogenesis and restenosis by activation of smooth muscle cell proliferation and neointima formation.