Link between infection and atherosclerosis: who are the culprits: viruses, bacteria, both, or neither?

The anti-atherosclerotic effects of natural polysaccharides: from phenomena to the main mechanisms of action

Polysaccharides (PSs) of plant origin have a variety of biological activities, anti-atherosclerotic including, but their use in atherosclerosis therapy is hindered by insufficient knowledge on the cellular and molecular mechanisms of action. In this review, the influence of several natural PSs on the function of macrophages, viral activity, and macrophage cholesterol metabolism has been discussed considering the tight interplay between these aspects in the pathogenesis of atherosclerosis. The anti-atherosclerotic activities of natural PSs related to other mechanisms have been also explored. Directions for further research of anti-atherosclerotic effects of natural PSs have been outlined, the most promising of which can be nutrigenomic studies.

Trends, outcomes, and management of acute myocardial infarction in patients with chronic viral hepatitis

OBJECTIVES

There is a paucity of data on the management and outcomes of chronic viral hepatitis (CVH) patients [including chronic hepatitis B (CHB) and chronic hepatitis C (CHC)] presenting with acute myocardial infarction (AMI).

METHODS

We utilized the National Inpatient Sample database (2001-2019) and studied the management and outcomes of CVH patients with AMI and stratified them by subtypes of CVH. The adjusted odds ratio (aOR) of adverse outcomes in CVH groups were compared to no-CVH groups using multivariable logistic regression.

RESULTS

Of 18,794,686 AMI admissions, 84,147 (0.45%) had a CVH diagnosis. CVH patients had increased odds of adverse outcomes including in-hospital mortality (aOR 1.40, 95%CI 1.31-1.49, p < 0.05), respiratory failure (1.11, 95%CI 1.04-1.17, p < 0.001), vascular complications (1.09, 95%CI 1.04-1.15, p < 0.001), acute kidney injury (1.36, 95%CI 1.30-1.42, p < 0.001), gastrointestinal bleeding (1.57, 95%CI 1.50-1.68, p < 0.001), cardiogenic shock (1.44, 95%CI 1.04-1.30, p < 0.001), sepsis (1.24, 95%CI 1.17-1.31, p < 0.001), and were less likely to undergo invasive management. On subgroup analysis, CHB had higher odds of adverse outcomes than the CHC group (p < 0.05).

CONCLUSION

CVH patients presenting with AMI are associated with worse clinical outcomes. CHB subgroup had worse outcomes compared to the CHC subgroup.

Impact of Direct-Acting Antivirals (daas) on cardiovascular diseases in patients with chronic hepatitis C

In the last years the hepatitis C virus (HCV) infection was a relevant public health problem due to the large number of affected people worldwide and the impact on hepatic and extrahepatic complications. The availability of direct-acting antivirals (DAAs) and the very high rate of sustained virological response (SVR) after treatment has radically changed the course of HCV chronic infection. Robust evidence showed a close link between HCV infection and development of cardiovascular disease (CVD), as result of the atherogenic effect of the virus. This review aims to explore the evidence linking HCV infection with cardiovascular disease and to evaluate the impact of SVR after DAAs on cardiovascular complications.

Short- and long-term outcomes following percutaneous coronary intervention in hepatitis C virus seropositive patients

Background

Hepatitis C virus (HCV) infection is progressively recognized as a potential atherogenic condition that is associated with coronary artery disease (CAD). Factors that affect the cardiovascular system as diabetes mellitus and dyslipidemia also may affect the outcomes following PCI. So, HCV infection may have an impact on the outcomes following PCI. We aimed to investigate the impact of HCV seropositivity on the outcomes following percutaneous coronary intervention (PCI).

Results

We conducted a multi-center prospective cohort study on 400 patients candidate for elective PCI using drug-eluting stents; 200 patients were HCV seropositive and did not received antiviral treatment, and 200 patients were HCV seronegative. The patients were followed up for 1 year for the development of major adverse cardiovascular events (MACEs) and clinical in-stent restenosis. Multivariate Cox hazard regression analyses for MACEs and clinical in-stent restenosis at 12 months after adjustment for confounding factors showed that HCV seropositivity did not present a higher hazard upon MACEs (adjusted hazard ratio (HR) 0.74; 95% CI 0.41–1.32; p value 0.302), the individual cardiovascular outcomes (target lesion revascularization (TLR), target vessel revascularization (TVR), myocardial infarction (MI), cerebrovascular stroke (CVS), stent thrombosis, major bleeding, coronary artery bypass graft (CABG), cardiac death, and non-cardiac death), or the incidence of clinical in-stent restenosis (adjusted HR was 1.70; 95% CI 0.64–4.51; p value 0.28) compared to seronegative patients.

Conclusion

HCV seropositivity had no impact on MACEs, individual cardiovascular outcomes, or clinical in-stent restenosis following PCI for a 1 year follow-up period.

High proviral load of human T cell lymphotropic virus type-1 facilitates coronary artery diseases

Objective(s):

Coronary artery disease (CAD) is known as a life threatening disease, worldwide. In this study the role of HTLV-1 infection was evaluated on cardiac involvement in an endemic region of northeastern Iran.

Materials and Methods:

Serologic and molecular tests for HTLV-1 infection were carried out in subjects who had coronary angiography. A real-time PCR, TaqMan method, to quantify HTLV-1 proviral load (PVL), and routine hematological and biochemical tests were performed for study subjects.

Results:

Twenty nine patients were HTLV-1+CAD+ and 13 cases were HTLV-1+CAD-. Although, there were no significant differences for risk factors like FBS, HDL, triglyceride, systolic and diastolic blood pressure (Cbp, Dbp), waist circumference (WC), hip circumference (WL), cholesterol (P=0.003), and LDL (P=0.007) levels, and monocyte count (P=0.05) had meaningful differences. The mean HTLV-1 PVL in HTLV-1+CAD+ subjects was 992.62±120 which was higher compared with HTLV-1+CAD- group (406.54±302 copies/104 PBMCs). Moreover, HTLV-1 PVL in males (833±108) was lower compared with females (1218±141 copies/104 PBMCs) (P=0.05). Patients with HTLV-1-PVL of more than 500 copies/104 had more diffused atherosclerosis plaque than patients with less than 500 (OR=6.87, 95% CI=1.34-35.05; P=0.016). Furthermore, patients with diffused coronary atherosclerosis had significantly higher levels of HTLV-1 PVL than patients with middle, proximal, and normal location of coronary sclerotic lesions (P<0.05).

Conclusion:

Taken together, in endemic area, HTLV-1 infection, more likely is a facilitating factor for heart complications and the high HTLV-1 PVL might affect CAD manifestations.

Risk of Cardiovascular Disease Due to Chronic Hepatitis C Infection: A Review

Hepatitis C (HCV) infection has an estimated global prevalence of 2.5%, causing chronic liver disease in 170 million people worldwide. Recent data has identified HCV infection as a risk factor for subclinical and clinical cardiovascular disease (CVD), but these data have been mixed and whether HCV is an independent risk factor for development of CVD remains controversial. In this review, we present the literature regarding the association of HCV with subclinical and clinical CVD and the possible underlying mechanisms leading to increased CVD among those infected with HCV. HCV infection leads to increased CVD via direct and indirect mechanisms with chronic inflammation, endothelial dysfunction and direct invasion of the arterial wall cited as possible mechanisms. Our review showed that HCV infection, particularly chronic HCV infection, appears to lead to increased subclinical CVD most consistently and potentially also to increased clinical CVD outcomes, leading to increased morbidity and mortality. Furthermore, the majority of studies evaluating the impact of HCV therapy on CVD morbidity and mortality showed an improvement in subclinical and clinical CVD endpoints in patients who were successfully treated and achieved sustained viral suppression. These results are of particular interest following the development of new direct antiviral agents which have made HCV eradication simple and feasible for many more patients globally, and in doing so may possibly reduce CVD morbidity and mortality in those with chronic HCV infection.

Latent tuberculosis infection among patients with erectile dysfunction

No previous studies have investigated the prevalence of latent tuberculosis infection (LTBI) among patients with erectile dysfunction (ED) or its contribution to the development of high-grade ED through a process of chronic inflammation-induced atherosclerosis. The aim of this study was to determine the frequency of LTBI among patients with erectile dysfunction and to explore the contribution of LTBI to high-grade ED. For all the study sample, clinical evaluation, imaging studies, and laboratory investigations were provided. Evaluation included, but was not confined to, scrotal ultrasonography, tuberculin skin test, and QuantiFERON-TB Gold test. The study sample mean ± SD age was 47.9 ± 13.6 years. Approximately 30% of the patients had LTBI and 43% had high-grade ED. After a multivariate analysis, it was found that older age (≥40 years) (OR, 5.2; 95% CI, 1.9-54.6; p 0.004), metabolic syndrome (MS) (OR, 3.4; 95% CI, 1.3-48.2; p 0.016), and LTBI (OR, 4.1; 95% CI, 1.7-61.3; p 0.021) were significantly, independently associated with high-grade ED as opposed to low-grade ED. In conclusion, the prevalence of LTBI among patients with high-grade ED is higher than among those with low-grade ED. In addition to LTBI, older age and MS are associated with high-grade ED as opposed to low-grade ED.

Prevalence of Hepatitis C Virus Seropositivity and Its Impact on Coronary Artery Disease among Egyptian Patients Referred for Coronary Angiography

Background. We tested the prevalence and impact of HCV seropositivity among Egyptian patients referred for coronary angiography. Subjects and Methods. This cross-sectional study was conducted in Zagazig University hospitals including 509 patients scheduled for elective coronary angiography between June 2013 and June 2014. By taking full history on admission, laboratory workup including HCV Ab, echocardiography study, and coronary angiography, we calculated the mean number of coronary artery lesions and the mean number of affected coronary artery vessels for all patients. The severity of the coronary lesions was estimated using the Gensini score. Results. HCV seropositive patients referred for coronary angiography were about 30.3% (which is greater than the prevalence of HCV seropositivity among general population in Egypt), patients proved to have CAD who are HCV antibody positive had more severe coronary lesions than in seronegative one (p < 0.05), and patients proved to have CAD who are HCV antibody positive had comparable prevalence of cardiovascular risk factors as seronegative patients except for diabetes and hypertension which are more prevalent in seronegative patients (p < 0.05). Conclusion. Prevalence of HCV antibody positive patients referred for coronary angiography was about 30.3%, and CAD patients who are HCV antibody positive had more severe coronary lesions and less prevalence of diabetes and hypertension than HCV antibody negative.

Translational informatics approach for identifying the functional molecular communicators linking coronary artery disease, infection and inflammation

Translational informatics approaches are required for the integration of diverse and accumulating data to enable the administration of effective translational medicine specifically in complex diseases such as coronary artery disease (CAD). In the current study, a novel approach for elucidating the association between infection, inflammation and CAD was used. Genes for CAD were collected from the CAD-gene database and those for infection and inflammation were collected from the UniProt database. The cytomegalovirus (CMV)-induced genes were identified from the literature and the CAD-associated clinical phenotypes were obtained from the Unified Medical Language System. A total of 55 gene ontologies (GO) termed functional communicator ontologies were identifed in the gene sets linking clinical phenotypes in the diseasome network. The network topology analysis suggested that important functions including viral entry, cell adhesion, apoptosis, inflammatory and immune responses networked with clinical phenotypes. Microarray data was extracted from the Gene Expression Omnibus (dataset: GSE48060) for highly networked disease myocardial infarction. Further analysis of differentially expressed genes and their GO terms suggested that CMV infection may trigger a xenobiotic response, oxidative stress, inflammation and immune modulation. Notably, the current study identified γ-glutamyl transferase (GGT)-5 as a potential biomarker with an odds ratio of 1.947, which increased to 2.561 following the addition of CMV and CMV-neutralizing antibody (CMV-NA) titers. The C-statistics increased from 0.530 for conventional risk factors (CRFs) to 0.711 for GGT in combination with the above mentioned infections and CRFs. Therefore, the translational informatics approach used in the current study identified a potential molecular mechanism for CMV infection in CAD, and a potential biomarker for risk prediction.

Contribution of Hepatitis B to Long-Term Outcome Among Patients With Acute Myocardial Infarction: A Nationwide Study

Although a possible association between hepatitis B and cardiovascular disease has been identified, the impact of viral hepatitis B on long-term prognosis after an acute myocardial infarction (AMI) is uncertain. Therefore, the aim of our study was to evaluate the specific impact of viral hepatitis B on survival after a first AMI through a retrospective analysis of data from the Taiwan National Health Insurance Research Database.This was a nationwide, propensity score-matched case-control study of patients admitted to hospitals between January 2000 and December 2012 with a primary diagnosis of a first AMI. Among the 7671 prospective patients, 244 patients with a confirmed diagnosis of viral hepatitis B infection were identified. A propensity score, one-to-one matching technique was used to match 244 controls to the AMI group for analysis. Controls were matched on the following variables: sex, age, hypertension, dyslipidemia, diabetes, peripheral vascular disease, heart failure, cerebrovascular accidents, end-stage renal disease, chronic obstructive pulmonary disease, and percutaneous coronary intervention (PCI).Overall, viral hepatitis B infection did not influence the 12-year survival rate (P = 0.98). However, survival was lower in female patients with viral hepatitis B infection compared to those without (P = 0.03; hazard ratio, 1.79; 95% confidence interval, 1.08-2.94). Inclusion of percutaneous coronary management improved survival, independent of sex, age, or hepatitis B status.Hepatitis B infection might increase the mortality risk of female patients after a first AMI. PCI may improve the long-term survival of patients after a first AMI, regardless of sex, age, and hepatitis B status.

The impact of hepatitis C infection on ischemic heart disease via ischemic electrocardiogram

BACKGROUND

Hepatitis C virus (HCV) infection is a serious disease worldwide and it leads to several serious hepatic sequels. Some studies find possible correlation between HCV and ischemic heart disease in retrospective observations. Based on lacked community-based evidence, the study aims to assess correlation between ischemic heart disease and chronic HCV infection via electrocardiogram (ECG) because its abnormalities is strongly associating with cardiovascular disease mortality.

METHODS

The population was from one community health examination in December 2010 in a southern village of Taiwan. A total of 9856 participants were evaluated and finally 5015 eligible residents with age older than 40 years were included. The baseline characteristics and laboratory data in nonischemic ECG and ischemic ECG groups were compared, and multivariate-adjusted analysis was used to evaluate the risks to ischemic ECG.

RESULTS

The higher prevalence of hypertension, metabolic syndrome and even HCV infection (25.3% versus 11.6%; P < 0.001) in ischemic ECG group than those in nonischemic ECG group. In the multivariate adjusted analysis, HCV infection would lead to a 1.759-fold risk to ischemic ECG when compared with non-HCV subjects.

CONCLUSIONS

HCV was strongly associated with ischemic ECG findings in this community study, and it could be a nonconventional risk factor for coronary artery disease.

Bacteria in the adventitia of cardiovascular disease patients with and without rheumatoid arthritis

The incidence of atherosclerosis is significantly increased in rheumatoid arthritis (RA). Infection is one factor that may be involved in the pathogenesis of both diseases. The cause of RA and atherosclerosis is unknown, and infection is one of the factors that may be involved in the pathogenesis of both diseases. The aims of this study were to identify bacteria in the aortic adventitia of patients with cardiovascular disease (CVD) in the presence and absence of RA, and to determine the effect of identified candidate pathogens on Toll-like receptor (TLR)-dependent signalling and the proinflammatory response. The aortic adventitia of 11 CVD patients with RA (RA+CVD) and 11 CVD patients without RA (CVD) were collected during coronary artery bypass graft surgery. Bacteria were detected in four samples from CVD patients and three samples from RA+CVD patients and identified by 16S rRNA gene sequencing. Methylobacterium oryzae was identified in all three RA+CVD samples, representing 44.1% of the bacterial flora. The effect of M. oryzae on TLR-dependent signalling was determined by transfection of HEK-293 cells. Although mild TLR2 signalling was observed, TLR4 was insensitive to M. oryzae. Human primary macrophages were infected with M. oryzae, and a TLDA qPCR array targeting 90 genes involved in inflammation and immune regulation was used to profile the transcriptional response. A significant proinflammatory response was observed, with many of the up-regulated genes encoding proinflammatory cytokines (IL-1α, IL-1β, IL-6, TNF-α) and chemokines (CCR7, IL-8). The aortic adventitia of CVD patients contains a wide range of bacterial species, and the bacterial flora is significantly less diverse in RA+CVD than CVD patients. M. oryzae may stimulate an proinflammatory response that may aggravate and perpetuate the pathological processes underlying atherosclerosis in RA patients.

NF-κB and hypoxia: a double-edged sword in atherosclerosis

This Commentary highlights the article by Fang et al, which describes novel mouse models of chronic intermittent hypoxia (CIH)-induced atherosclerosis, revealing that loss of the NF-κB p50 subunit increased atherosclerosis in the presence of CIH.

Effect of filarial infection on serum inflammatory and atherogenic biomarkers in coronary artery disease (CURES-121)

Helminth infections can potentially confer protection against metabolic disorders, possibly through immunomodulation. In this study, the baseline prevalence of lymphatic filariasis (LF) among subjects without (N = 236) and with (N = 217) coronary artery disease (CAD) was examined as part of the Chennai Urban Rural Epidemiological Study (CURES). The prevalence of LF was not significantly different between CAD(-) and CAD(+) subjects. The LF antigen load and antibody levels indicated comparable levels of infection and exposure between the groups. Within the CAD group, LF(+) and LF(-) subjects had no significant difference in the intimal medial thickness and high-sensitivity C-reactive protein values. However, LF infection was associated with augmented levels of tumor necrosis factor-α and interleukin-6 among CAD(+) subjects. The LF infection had no effect on serum adipocytokine profile. In conclusion, unlike type-2 diabetes, there is no association between the prevalence of LF and CAD and also no evidence of protective immunomodulation of LF infection on CAD in the Asian Indian population.

Host cholesterol and inflammation as common key regulators of toxoplasmosis and artherosclerosis development

Atherosclerosis and toxoplasmosis are two widely prevalent diseases worldwide. The relationship between these diseases is now being elucidated. Atherosclerosis is a disease with three main components: increased blood lipoprotein/cholesterol and their deposition in the arterial wall, an important Th1-mediated proinflammatory reaction and thrombogenic status. Toxoplasma gondii, in turn, is dependent on host cholesterol for optimal intracellular growth and replication. As a result, host cholesterol will be cleared from the blood, reducing plasma low-density lipoprotein, a crucial atherosclerosis risk factor. On the other hand, T. gondii infection elicits an important Th1 systemic inflammatory response in the host. Therefore, this additional proinflammatory stimulus may impose an enhanced pro-atherogenic environment in the host. As result, the association between these two diseases in one individual could change the course of atherosclerosis. In this review, we demonstrate that the host-parasite relationship is complex and that the outcome of each disease is dependent on the availability of intracellular cholesterol, as well as the intensity of the inflammatory reaction triggered by the parasite. We also discuss the possible clinical implications of these studies.

Association between Histoplasma exposure and stroke

BACKGROUND AND PURPOSE

The rate of cerebrovascular events within the stroke belt, a geographic area defined in the Southeastern United States, exceeds that of the rest of the nation. Despite evaluation of multiple risk factors for this disparity, specific causes for the stroke belt have not been elucidated. More than 45 years ago, the US Public Health Service and US Navy cooperative skin-testing program (1958-1965) documented adolescent exposure to Histoplasma capsulatum. Our purpose was to evaluate the association between exposure to Histoplasma capsulatum and subsequent development of stroke.

METHODS

A cross-sectional study of stroke in a cohort of US Navy veterans was designed to assess our hypothesis. Medical records from 23,795 men who participated in the cooperative skin-testing program and who received medical care at Veterans Administration Hospitals and Clinics were reviewed. A logistic regression model was used to estimate the odds ratio of stroke while controlling for multiple covariates. Because of the large number of possible risk factors for stroke, propensity scores were used to reduce bias.

RESULTS

The adjusted odds ratio for stroke in veterans exposed to Histoplasma capsulatum during adolescence was 1.34 (95% confidence interval: 1.1-1.6; P = .0033). The increased risk was independent of traditional cerebrovascular event risk factors. Less frequent risk factors (atrial fibrillation, coronary heart disease, rheumatic heart disease, and prosthetic cardiac valvular replacement) were not controlled in this model.

CONCLUSION

Exposure to Histoplasma capsulatum during adolescence was associated with an increased risk of stroke.

Hepatitis B Virus Infection and the Risk of Coronary Atherosclerosis

Introduction: Many studies have reported on the association between human coronary artery disease (CAD) and certain persistent bacterial and viral infections. Currently, it is unclear whether hepatitis B virus infection is associated with the risk of the atherosclerosis. The aim of this study was to investigate the possible association between hepatitis B virus infection and angiography-proven CAD. Materials and Methods: Sera from 5004 patients who underwent coronary angiography were tested for hepatitis B surface antigen (HBsAg) by enzyme-linked immunosorbant assay at Madani Heart Hospital, Tabriz University of Medical Sciences, Iran. Results: Our study population comprised 66% male and 34% female, with an age range of 36 to 86 years. The prevalence of HBsAg positivity tended to be higher in CAD patients than in those without CAD (3.28% versus 2.17%), but the difference was not statistically significant. Conclusion: Our results suggest that hepatitis B virus infection is not associated with coronary atherosclerosis in this population. Key words: Atherosclerosis, Coronary artery disease, Hepatitis B virus

The association between hepatitis C infection and prevalent cardiovascular disease among HIV-infected individuals

OBJECTIVE

To examine the association between hepatitis C and prevalent cardiovascular disease (CVD) among HIV-infected individuals.

DESIGN

A cross-sectional analysis of data from the HIV-Longitudinal Interrelationships of Viruses and Ethanol (HIV-LIVE) cohort, a prospective cohort of HIV-infected individuals with current or past alcohol problems.

METHODS

We analysed health questionnaire and laboratory data from 395 HIV-infected individuals (50.1% co-infected with hepatitis C) using logistic regression to estimate the odds ratio (OR) for the prevalence of CVD among those co-infected with hepatitis C and HIV compared with those infected with HIV alone.

RESULTS

The prevalence of CVD was higher among those co-infected with hepatitis C compared with those with HIV alone (11.1 versus 2.5%, respectively). After adjusting for age, the OR for the prevalence of CVD was significantly higher among those with hepatitis C co-infection (adjusted OR 4.65, 95% confidence interval 1.70-12.71). The relationship between hepatitis C and CVD persisted when adjusting for age and other sociodemographic characteristics, substance use, and cardiovascular risk factors in separate regression models.

CONCLUSION

Co-infection with hepatitis C among a cohort of HIV-infected individuals was associated with a higher age-adjusted odds for the prevalence of CVD. These data suggest that hepatitis C infection may be associated with an increased risk of CVD among those co-infected with HIV.

Inflammation in coronary artery disease: potential role for immunomodulatory therapy

Understanding of the mechanisms underlying atherosclerotic disorders has evolved beyond the view of a progressive collection of lipids and cellular debris in the vascular wall. Current evidence has implicated inflammatory pathways as an important pathogenic mechanism in atherogenesis and plaque destabilization. Although not necessarily the primary event, inflammation and cytokine activation during plaque formation and destabilization may represent a common final pathway to various stimuli. Thus, it seems that not only 'new' risk factors, such as infections with various microorganisms, but also classic risk factors for cardiovascular disease, such as hyperlipidemia, hypertension and diabetes, may promote their atherogenic effects through inflammatory responses. Indeed, recent reports have suggested that traditional cardiovascular medications may attenuate atherogenesis and enhance plaque stability, at least partly through anti-inflammatory mechanisms. However, uncovering the inflammatory pathways in atherosclerosis has raised the possibility that newer treatment modalities should be more directly targeted against inflammatory mediators. Recently, a series of experimental studies have reported reduction of atherosclerosis by immunomodulatory therapy, such as chemokine blockade, interleukin-10 and immunization/vaccination against oxidized low-density lipoprotein and heat-shock protein. It is conceivable that some of these approaches will be tested clinically and, if successful, they could provide novel treatment strategies in coronary artery disease in humans.

The relation of lipid peroxidation processes with atherogenesis: A new theory on atherogenesis

The extremely high sensitivity of polyunsaturated fatty acids (PUFAs) to oxygen is apparently used by nature to induce stepwise appropriate cell responses. It is hypothesized that any alteration in the cell membrane structure induces influx of Ca2+ ions. Ca2+ ions are required to activate degrading enzymes, such as phospholipases and lipoxygenases (LOX) that transform PUFAs bound to membrane phospholipids to lipidhydroperoxides (LOOHs). Enzymatic reduction products of LOOHs seem to serve as ligands of proteins, which induce gene activation to initiate a physiological response. Increasing external impact on cells is connected with deactivation of LOX, liberation of the iron ion in its active center followed by cleavage of LOOH molecules to LO * radicals. LO * radicals induce a second set of responses leading to generation of unsaturated aldehydic phospholipids and unsaturated epoxyhydroxy acids that contribute to induction of apoptosis. Finally peroxyl radicals are generated by attack of LO * radicals on phospholipids. The latter attack nearly all types of cell constituents: Amino- and hydroxyl groups are oxidized to carbonyl functions, sugars and proteins are cleaved, molecules containing double bonds such as unsaturated fatty acids or cholesterol suffer epoxidation. LOOH molecules and iron ions at the cell wall of an injured cell are in tight contact with phospholipids of neighboring cells and transfer to these reactive radicals. Thus, the damaging processes proceed and cause finally necrosis except the chain reaction is stopped by scavengers, such as glutathione. Consequently, PUFAs incorporated into phospholipids of the cell wall are apparently equally important for the fate of a single organism as the DNA in the nucleus for conservation of the species. This review intends to demonstrate the connection of cell alteration reactions with induction of lipid peroxidation (LPO) processes and their relation to inflammatory diseases, especially atherosclerosis and a possible involvement of food. Previously it was deduced that food rich in cholesterol and saturated fatty acids is atherogenic, while food rich in n-3 PUFAs was recognized to be protective against vascular diseases. These deductions are in contradiction to the fact that saturated fatty acids withstand oxidation while n-3 PUFAs are subjected to LPO like all other PUFAs. Considering the influence of minor food constituents a new theory about atherogenesis and the influence of n-3 PUFAs is represented that might resolve the contradictory results of feeding experiments and chemical experiences. Cholesterol-PUFA esters are minor constituents of mammalian derived food, but main components of low density lipoprotein (LDL). The PUFA part of these esters occasionally suffers oxidation by heating or storage of mammalian derived food. There are indications that these oxidized cholesterol esters are directly incorporated into lipoproteins and transferred via the LDL into endothelial cells where they induce damage and start the sequence of events outlined above. The deduction that consumption of n-3 PUFAs protects against vascular diseases is based on the observation that people living on a fish diet have a low incidence to be affected by vascular diseases. Fish are rich in n-3 PUFAs; thus, it was deduced that the protective properties of a fish diet are due to n-3 PUFAs. Fish, fish oils, and vegetables contain besides n-3 PUFAs as minor constituents furan fatty acids (F-acids). These are radical scavengers and are incorporated after consumption of these nutrients into human phospholipids, leading to the assumption that not n-3 PUFAs, but F-acids are responsible for the beneficial efficiency of a fish diet.

A High Calcium-Phosphate Product Is Associated with High C-Reactive Protein Concentrations in Hemodialysis Patients

BACKGROUND

An elevated CaxPO4 product and C-reactive protein (CRP) have been associated with coronary artery calcification and increased cardiovascular mortality in hemodialysis (HD) patients. However, it has not been defined, so far, whether and how both parameters are related to each other. For this reason we have evaluated in a cross-sectional and in an interventional study the possible correlation between CaxPO4 and CRP and the effect of the correction of a high CaxPO4 on CRP levels.

METHODS

47 uremic patients (age 65 +/- 16 years) on regular chronic HD were selected from a total population of 125 prevalent patients treated at our Institution. Patients had no clinical evidence of either acute infectious or inflammatory diseases for at least 4 weeks before the study. They were on regular bicarbonate HD for 6-329 months (median 42). CRP, hemoglobin (Hb), serum albumin (sAlb), protein catabolic rate (PCRn), serum calcium (Ca), serum phosphorus (PO4), CaxPO4, intact PTH, Kt/V, presence of ischemic heart disease (IHD) and/or peripheral vascular disease (PVD) were recorded. CRP was Ln-transformed in all statistical analyses because of positive skewness.

RESULTS

The main findings were: LnCRP 2.17 +/- 0.77 mg/l, Ca 10.1 +/- 0.4 mg/dl, PO4 5.8 +/- 0.6 mg/dl, CaxPO4 59 +/- 6 mg2/dl2, andPTHint 218 +/- 195 ng/ml. 18/47 had IHD, 18/47 PVD. A significant hyperbolic correlation between CaxPO4 and CRP was observed. A piecewise linear regression model analysis identified a break-point for CaxPO4 at 55 mg2/dl2. Comparison of CRP levels after the division of the patients into two groups according to CaxPO4 break-point (group A, CaxPO4 < or = 55 mg2/dl2, n = 16 patients; group B, CaxPO4 >55 mg2/dl2, n = 31 patients) showed that CRP levels were significantly lower in patients in group A (LnCRP 1.43 +/- 0.22 mg/l) than in group B (LnCRP 2.55 +/- 0.67 mg/l, p < 0.0001). Multiple regression analysis bearing LnCRP as dependent variable confirmed CaxPO4 as the most significant variable among the other variables examined. In 22 patients with CaxPO4 > or = 60 mg2/dl2, we performed intensive lowering of the CaxPO4 product in order to reach and maintain a CaxPO4 , or =55 mg2/dl2 for 3 months. At the end of observation, a significant reduction in CaxPO4 and LnCRP was observed (CaxPO4 pre 62.8 +/- 1.9 vs. post 46.3 +/- 6.2 mg2/dl2: p < 0.0001; LnCRP pre 2.32 +/-0.36 vs. post 1.83 +/- 0.14 mg/l: p < 0.0001). No significant variation in the other biochemical parameters was observed.

CONCLUSIONS

Our data show that in chronic HD patients in steady clinical conditions with no clinical evidence of either infectious or inflammatory diseases, a high CaxPO4 is associated with high CRP concentrations. Intensive lowering of CaxPO4 reduces CRP

Viral load of the human immunodeficiency virus could be an independent risk factor for endothelial dysfunction

BACKGROUND

Recent reports of myocardial infarction in young persons infected with human immunodeficiency virus (HIV) who are receiving protease inhibitor therapy have raised concerns about premature coronary artery disease in this population. However, endothelial dysfunction, hypercoagulability, hypertriglyceridemia, and abnormal coronary artery pathology have been observed in association with HIV infection prior to the availability of protease inhibitor therapy.

HYPOTHESIS

The study was undertaken to determine the association between endothelial function, viral load, CD4+ count, and other well-established risk factors for atherosclerosis.

METHODS

This prospective, case-controlled study compared viral (HIV) load and the CD4+ T-lymphocyte count and endothelial function in 24 HIV-positive carriers. Brachial artery diameter, HIV viral load, and CD4 count were measured.

RESULTS

We found that viral load correlated inversely with endothelial function; the higher the viral load, the worse the endothelial dysfunction (p < 0.005).

CONCLUSION

High viral load appears to be associated with endothelial dysfunction in patients with HIV. This preliminary observation supports the infectious theory that viruses may play an important role in the pathogenesis of atherosclerosis.

Serum and peripheral blood mononuclear cells infectious burden: Correlation to inflammation and atherosclerosis in haemodialysis patients

BACKGROUND

Infectious agents may be implicated in the inflammatory atherosclerotic process. Not only specific microorganisms but also the infectious burden, defined as the number of pathogens to which a patient is exposed, has been associated with atherosclerosis. In the present study, the infectious burden, determined directly (by identification of viable pathogens in peripheral blood mononuclear cells (PBMC)) and indirectly (by serum antibodies detection) is correlated to the inflammatory and atherosclerotic status in haemodialysis (HD) patients, a population at high risk for cardiovascular disease.

METHODS

The viable forms of four microorganisms (Chlamydia pneumoniae, herpes virus 1 and 2 and cytomegalovirus) were identified in patients PBMC by cell cultures and subsequent polymerase chain reaction. Serum IgG against the above pathogens and Helicobacter pylori were also determined. Inflammation was assessed by measurement of C-reactive protein (CRP), serum amyloid A (SAA), three pro- and one anti-inflammatory cytokines and four adhesion molecules. Atherosclerosis was defined by a scoring system using medical history data.

RESULTS

The number of viable pathogens identified in PBMC in the 122 HD patients included in the study were zero in 22.1% of them, one in 33.6%, two in 43.4% and three in one patient. The number of IgG antibodies determined was one in 6.6% of patients, two in 32%, three in 48.4% and four in 13.1%. Seropositivity was not significantly different between patients with or without the respective viable pathogen identified in PBMC. Atherosclerosis was present in 40.2% of patients, and CRP, SAA and interleukin-6 were all increased in these patients. Neither inflammatory indexes nor atherosclerosis were significantly different in patients with a higher number of viable pathogens detected in PBMC or in those with a higher antibodies number.

CONCLUSIONS

The direct infectious burden determination (the number of viable pathogens in PBMC) does not coincide with the serum (by IgG detection) infectious burden. Although inflammation correlates to atherosclerosis, neither PBMC nor the serum infectious burden is associated with these two entities in the inflamed and atherosclerotic HD patients.

Lipopolysaccharide induces 5-lipoxygenase-activating protein gene expression in THP-1 cells via a NF-κB and C/EBP-mediated mechanism

We examined induced expression of the 5-lipoxygenase-activating protein (FLAP), which is critical for leukotriene synthesis in mononuclear phagocytes. Prolonged exposure to the bacterial component, lipopolysaccharide (LPS), increased FLAP gene transcription, mRNA expression, and protein expression in the human monocyte-like THP-1 cell line. Activation and inhibition of the NF-κB pathway modulated LPS induction of FLAP gene expression. An NF-κB-mediated mechanism of action was supported by overexpression of dominant-negative IκBα and p50/p65 proteins. EMSA/supershift and DNase I footprint analyses revealed that p50 binds to an NF-κB site located in the proximal FLAP promoter, while chromatin immunoprecipitation assays demonstrated that LPS induced binding of p50 but not of p65. Moreover, EMSA/supershift analyses demonstrated that LPS induced time-dependent binding of THP-1 nuclear extracts (containing p50) to this promoter region. Mutation of the NF-κB site decreased basal promoter activity and abolished the p50- and p65-associated induction. EMSA/supershift analyses also demonstrated that LPS induced binding of THP-1 nuclear extracts [containing CCAAT/enhancer binding protein (C/EBP)-α, -δ, and -ε] to a C/EBP site located adjacent to the NF-κB site in the FLAP promoter. We conclude that LPS enhances FLAP gene expression via both NF-κB- and C/EBP-mediated transcriptional mechanisms in mononuclear phagocytes.

Demonstration of intracellular microorganisms (Rickettsia spp., Chlamydia pneumoniae, Bartonella spp.) in pathological human aortic valves by PCR

OBJECTIVES

Rickettsiae, which causes vasculitis, has not been linked to atherosclerotic cardiovascular disease in contrast to Chlamydia pneumoniae whose association with coronary artery disease and with sclerotic heart valves in patients undergoing aortic valve replacement is well established, even if causality is yet to unproven. In the search for any of these infectious agents, 84 pathological and 15 normal aortic heart valves of patients undergoing forensic autopsy were analysed by PCR and DNA-sequencing.

METHODS

Two to four pieces of all valves were examined by semi-nested PCR, with primers specific for 16S rDNA, citrate synthase (gltA) and 17 kDa outer membrane protein (OMP) genes.

RESULTS

Genetic material from Rickettsia spp. and C. pneumoniae was found in 17 (20.2%) and 22 (26.2%), respectively, of the 84 pathological aortic valves. In 35 (41.7%) of these 84 valves either C. pneumoniae or Rickettsia spp. were detected by PCR and in six cases (7.1%) these two organisms co-existed. In one case with Lambl's excrescences, previously considered as aseptic, presence of rickettsia-like organisms also was demonstrated by light microscopy, immunohistochemistry and sequencing of the amplified PCR product showing 100% homology with the published sequence for R. helvetica. In three of the 15 control valves, genetic material from only C. pneumoniae was detected compared to Rickettsia spp. that was significantly detected only in the pathological valves (Fisher's Exact test, 1-sided p = 0.046).

CONCLUSIONS

The findings suggest that Rickettsia spp. also have a role in the pathogenesis of aortic valve disease.

HIV-associated coronary artery disease

Cases, case series, and related articles on coronary artery disease in patients with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) identified through a comprehensive literature search were examined for clinical characteristics and angiographic findings of HIV-associated coronary artery disease. Among 129 identified cases, 91% were males. The mean age was 42.3 +/- 10.2 (SD) years (range, 23 to 77 years). The interval between the diagnosis of HIV infection and the diagnosis of coronary artery disease was 72 +/- 60 (SD) months. Degree of immunosuppression was variable (CD4 mean, 313 +/- 209 cells/mm3; range, 6-1070 cells/mm3). There was no correlation between the CD4 cell count and the development and progression of coronary artery disease. Similarly, the development and progression of coronary artery disease was independent of the presence of HIV-related opportunistic infections. Acute myocardial infarction was the initial presentation in 77% of patients. In 76 patients, information on diseased vessels was available: 36 (47%) patients had 3-vessel disease, 14 (18%) patients had 2-vessel disease, and 26 patients (35%) had 1-vessel disease. The left anterior descending artery was involved in 47 (62%) patients while the left circumflex and right coronary arteries were involved in 34 (45%) and 38 (50%) patients, respectively. Thirty-two (25%) patients underwent catheter-based or surgical revascularization. Data were not adequate to assess the prognosis following the acute coronary events or revascularization. The histologic characteristics unique to HIV-associated coronary arteriopathy were diffuse circumferential involvement of the vessel with an unusual proliferation of smooth muscle cells, mixed with abundant elastic fibers, resulting in endoluminal protrusions. Coronary artery disease was a late complication of AIDS.

Chronic infections and atherosclerosis/thrombosis

An emerging pathophysiologic paradigm implicates chronic inflammation in the initiation, progression, and destabilization of atherosclerotic vascular disease. Various potential contributors to the inflammatory response in the vessel wall include atherogenic lipids, mechanical stress and injury, hypertension and angiotensin II, cigarette smoking, immune response to neoantigens, and chronic infections with viruses and or bacteria (Table 1). The potential link between chronic infection and atherosclerosis/thrombosis is under extensive investigation in several laboratories around the world. Although indirect evidence and experimental data tend to support this link, definitive proof is still lacking. If such a link is eventually proven to be causal in nature, it will provide a novel target for preventive and therapeutic strategies (anti-infective drugs, vaccines, etc.) against a common disease that is the leading killer of people in Western nations. Results of ongoing, large-scale clinical trials are eagerly awaited.

P2 receptors: new potential players in atherosclerosis

Atherosclerosis is a focal inflammatory disease of the arterial wall. It starts with the formation of fatty streaks on the arterial wall that evolve to form a raised plaque made of smooth muscle cells (SMCs), and infiltrating leukocytes surrounding a necrotic core. The pathogenesis of the atherosclerotic lesion is incompletely understood, but it is clear that a dysfunction of the endothelium, recruitment and activation of inflammatory cells and SMC proliferation have a pivotal role. Over recent years receptors for extracellular nucleotides, the P2 receptors, have been recognized as fundamental modulators of leukocytes, platelets, SMCs and endothelial cells. P2 receptors mediate chemotaxis, cytokine secretion, NO generation, platelet aggregation and cell proliferation in response to accumulation of nucleotides into the extracellular milieu. Clinical trials have shown the benefit of antagonists of the ADP platelet receptor(s) in the prevention of vascular accidents in patients with atherosclerosis. Therefore, we anticipate that a deeper understanding of the involvement of P2 receptors in atheroma formation will open new avenues for drug design and therapeutic intervention.

Inflammatory mechanisms

Traditional concepts of the pathogenesis of acute coronary syndromes have changed over the last few years. In particular it has been demonstrated that high-risk lesions are not necessarily angiographically severe. Rather, unstable high risk lesions are the ones composed of large lipid cores and thin fibrous caps. It is now widely accepted that plaque instability is related to the development of inflammation within the intima. A consequence of this is that stabilization of lesions provides a new therapeutic target. Furthermore, there is growing evidence that statins may stabilize lesions by altering the inflammatory response. A brief overview of these developments and their impact on clinical practice is presented.