Are morphological or functional changes in the carotid artery wall associated with Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, or herpes simplex virus infection?

Atherosclerosis Associated With COVID-19: Acute, Tends to Severely Involve Peripheral Arteries, and May be Reversible

Arterial stiffness was reported with corona virus disease 2019 (COVID-19). We studied atherosclerosis in COVID-19 directly through duplex ultrasound measurements and their relation to co-morbidities, clinical and laboratory severity markers, and serum interleukin (IL) 6 and 17. Serum IL 6 and 17, average carotid intima-media thickness (cIMT), diameter and peak systolic velocities (PSV) of tibial, ulnar, radial arteries, and ankle brachial index (ABI) were measured in 44 COVID-19 patients and 44 healthy controls. Serum IL6, IL17, PSV, and cIMT were higher while diameter was lower (P ≤ .01) in cases. Clinical severity index correlated positively with age, co-morbidities, ferritin, IL6, IL17, cIMT, and PSV (P ≤ .04) and negatively with diameter and ABI (P = .04). Patients with severe lymphopenia had higher PSV, IL6, and IL17 and lower diameter (P < .00001). Ferritin positively correlated with PSV and negatively with diameter and ABI (P ≤ .01). Those who received an IL6 inhibitor (tocilizumab) showed lower PSV and higher diameter (P ≤ .01). In multiple regression analysis, IL17 and (age, co-morbidities) were related to (PSV, diameter) and cIMT (P ≤ .001, ≤0.02), respectively. COVID-19 may be associated with subclinical acute and may be reversible atherosclerosis severely involving peripheral arteries.

Are We Aware of the Neurological Manifestations of Cytomegalovirus Infection in Immunocompetent Individuals?

BACKGROUND

While cytomegalovirus (CMV) infection usually causes disease in immunosuppressed individuals, it mostly progresses as an asymptomatic infection in healthy adults. However, very rarely, immunocompetent individuals may also suffer from encephalitis and stroke.

METHODS

Nine patients who were admitted to the Neurology Clinic of Abant Izzet Baysal University Faculty of Medicine from 2016 to 2020 who had various neurological symptoms and were diagnosed with CMV infection were retrospectively analyzed. Symptoms, examination findings, laboratory results, radiologic imaging, and treatments were recorded and evaluated.

RESULTS

Although severe infections because of CMV generally occur in newborns and immunosuppressed adults, it is estimated that the disease is more common in immunocompetent adults than known. This may be associated with unrecognized risks, in part because of immune dysfunction or comorbidities such as renal failure or diabetes mellitus. Also, CMV replication in arterial endothelial cells can restrict blood flow, inducing an atherosclerotic environment and causing stroke. Diagnosis is based on clinical suspicion and serology. Ganciclovir is administered for treatment.

CONCLUSION

CMV infection should be considered in the differential diagnosis of patients presenting with neurological symptoms, even among immunocompetent individuals, because of the high possibility that patients can greatly benefit from antiviral treatment at the early stage.

[Infections and inflammation in the development of stroke]

The review systematizes data on the role of infectious diseases and systemic inflammation in the pathogenesis of stroke. Various risk factors for stroke associated with pro-inflammatory reactions and their contribution to the pathogenesis of cerebrovascular pathology are analyzed. The interaction of systemic inflammation with hemostasis disturbances and clots formation, activation of autoreactive clones of cytotoxic lymphocytes, the progression of endothelial damage, and other processes is shown. Along with infection, these factors increase the risk of stroke. The key mechanisms of the pathogenesis from the development of acute or chronic inflammation to the preconditions of stroke are presented. The mechanisms of the acting of the infectious process as a trigger factor and/or medium-term or long-term risk factors of stroke are described. A separate section is devoted to the mechanisms of developing cerebrovascular diseases after COVID-19. Identifying an increased risk of stroke due to infection can be of great preventive value. Understanding of this risk by specialists followed by correction of drug therapy and rehabilitation measures can reduce the incidence of cerebrovascular complications in infectious patients.

Chlamydia pneumoniae and Mycoplasma pneumoniae as two Emerging Risk Factors in Atherosclerosis: Meta-Analysis Study and Systematic Review

BACKGROUND

Previous studies suggested an association between Chlamydia pneumoniae and Mycoplasma pneumonia with atherosclerosis, separately. Until now, according to inconsistent information, the relationship between C.pneumoniae and M.pneumoniae with atherosclerosis is controversial.

OBJECTIVE

the aim of this study, investigate of the association between C.pneumoniae and M.pneumoniae as two separate risk factors with atherosclerosis by systematic review and meta-analysis study.

METHODS

We searched databases such as Pubmed, SID, Magiran, Google scholar and Iranmedex using the following keywords in English and Persian language as C. pneumoniae , M. pneumoniae and atherosclerosis. Data were analyzed with meta-analysis and a random effect model. Also, in this study Heterogeneity of articles were estimated by using I2 index. Finally, data was analyzed with STAT (version 11.2) Results: Among thirty-eight articles for C. pneumoniae and five articles for M. pneumoniae individually reviewed that included 2980 samples for M. pneumoniae and 23298 samples for C. pneumoniae, result demonstrated that association between M. pneumoniae and C. pneumoniae with atherosclerosis is significant with OR (odd ratio) = 1.58 (95% Confidence Interval (CI): 1.00 to 2.50), OR (odd ratio) = 2.25(95% Confidence Interval (CI): 1.91 to 2.64), respectively.

CONCLUSION

This systematic review study provides strong evidence for the role of persistent bacterial infection such as M. pneumoniae and C. pneumoniae in potential atherosclerosis. Thus, a novel way should be employed for the complete management of bacterial infection.

Association between Helicobacter pylori infection and carotid atherosclerosis in Chinese adults

Background and aims

The role of Helicobacter pylori (H. pylori) infection in carotid atherosclerosis remains inconsistent and sometimes controversial. We aimed to determine whether H. pylori infection is associated with carotid atherosclerotic plaques in a large number of Chinese adults.

Methods

We recruited 108,210 Chinese adults who participated in a standard medical screening with both carotid ultrasonic examination and ¹³C-urea breath test for H.pylori infection from two Chinese cohorts. A total of 93,915 adults were included in the analysis after excluding participants with cardiovascular disease (CVD) and carotid plaques at baseline. Hazard ratio (HR) for developing carotid plaques by H. pylori infection was analyzed using the Cox proportional hazard model, with sociodemographic and clinical factors adjusted. Findings across cohorts were pooled by meta-analyses.

Results

11,208 (13.13%) participants occurred carotid plaques at a median follow-up of 20 months in the MN cohort, while 1279 (14.95%) participants occurred carotid plaques at a median follow-up of 24 months in the MJ cohort. Compare with participants without H. pylori infection, participants with H. pylori infection were more likely to occur carotid plaques. After adjusting for age, sex, annual personal income, body mass index, blood pressure, blood glucose, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and estimated glomerular filtration rate, the HR was 1.04 (95%CI: 1.01-1.08). After further adjusting for education level, marital status, smoking status, alcohol drinking status, physical activity, and family history of CVD, the HR changed minimally. Additional sensitivity analyses confirmed the robustness of the results. Significant interactions of age, sex, blood pressure, blood glucose, or chronic inflammation were not observed in this research.

Conclusions

H. pylori infection was associated with carotid plaque onset in a large number of Chinese adults without previous CVD. These data suggested that the prevention of H. pylori infection may reduce the burden of carotid atherosclerosis.

Helicobacter pylori infection and susceptibility to cardiac syndrome X: A systematic review and meta-analysis

BACKGROUND

Cardiac syndrome X (CSX) is characterized by persistent angina with normal coronary arteries. Several pathophysiologic mechanisms have been introduced, particularly Helicobacter pylori (H. pylori) infection.

AIM

To investigate the association between H. pylori infection and CSX.

METHODS

All studies related to H. pylori infection and CSX were evaluated by comprehensive searches of global databases such as ISI Web of Knowledge, PubMed, Scopus, EMBASE, and Google scholar. Statistical analyses of selected articles were evaluated based on the summary odds ratio (OR). Finally, heterogeneity and publication bias were estimated using the I² statistic and Cochrane Q-test as well as Begg’s and Egger’s tests.

RESULTS

A total of 11 studies met our inclusion criteria and 1435 patients (63% female, and 37% male) were reviewed. A significant association was observed between female patients and this syndrome (P = 0.02). Our results showed a positive association between infection with this pathogen and presence of CSX (OR: 5.65; 95% confidence interval [CI]: 4.17-7.64; I²: 82.20). However, no significant association was observed with cagA-positive H. pylori strains and this syndrome (OR: 0.97; 0.56-1.70 with 95%CI). Given the heterogeneity and publication bias, the results need to confirmed by further prospective investigation.

CONCLUSION

Based on our results, H. pylori infection is associated with an increased risk of CSX. This bacterium appears to play a major role in the pathogenesis of CXS by inducing persistent inflammation.

Carotid stiffness, intima-media thickness and aortic augmentation index among adults with SARS-CoV-2

New Findings

What is the central question of this study?

We sought to investigate whether carotid stiffness, carotid intima–media thickness and the aortic augmentation index are altered in young adults 3–4 weeks after contraction of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) compared with young healthy adults.

What is the main finding and its importance?

We found that carotid stiffness, Young's modulus and the aortic augmentation index were greater in young adults who tested positive for SARS‐CoV‐2 compared with healthy young adults. These findings provide additional evidence for detrimental effects of SARS‐CoV‐2 on young adult vasculature, which might have implications for cardiovascular health.

Abstract

Contracting severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has been observed to cause decrements in vascular function of young adults. However, less is known about the impact of SARS‐CoV‐2 on arterial stiffness and structure, which might have additional implications for cardiovascular health. The purpose of this study was to assess the carotid artery stiffness and structure using ultrasound and the aortic augmentation index (AIx) using applanation tonometry in young adults after they tested positive for SARS‐CoV‐2. We hypothesized that carotid artery stiffness, carotid intima–media thickness (cIMT) and aortic AIx would be elevated in young adults with SARS‐CoV‐2 compared with healthy young adults. We evaluated 15 young adults (six male and nine female; 20 ± 1 years of age; body mass index, 24 ± 3 kg m⁻²) 3–4 weeks after a positive SARS‐CoV‐2 test result compared with young healthy adults (five male and 10 female; 23 ± 1 years of age; body mass index, 22 ± 2 kg m⁻²) who were evaluated before the coronavirus 2019 pandemic. Carotid stiffness, Young's modulus and cIMT were assessed using ultrasound, whereas aortic AIx and aortic AIx standardized to 75 beats min⁻¹ (AIx@HR75) were assessed from carotid pulse wave analysis using SphygmoCor. Group differences were observed for carotid stiffness (control, 5 ± 1 m s⁻¹; SARS‐CoV‐2, 6 ± 1 m s⁻¹), Young's modulus (control, 396 ± 120 kPa; SARS‐CoV‐2, 576 ± 224 kPa), aortic AIx (control, 3 ± 13%; SARS‐CoV‐2, 13 ± 9%) and aortic AIx@HR75 (control, −3 ± 16%; SARS‐CoV‐2, 10 ± 7%; P < 0.05). However, cIMT was similar between groups (control, 0.42 ± 0.06 mm; SARS‐CoV‐2, 0.44 ± 0.08 mm; P > 0.05). This cross‐sectional analysis revealed higher carotid artery stiffness and aortic stiffness among young adults with SARS‐CoV‐2. These results provide further evidence of cardiovascular impairments among young adults recovering from SARS‐CoV‐2 infection, which should be considered for cardiovascular complications associated with SARS‐CoV‐2.

Association of recurrent common infections and subclinical cardiovascular disease in Mexican women

BACKGROUND

Acute and agent-specific chronic infections have been associated with increased cardiovascular risk, however data on the burden of common recurrent infections on cardiovascular disease is limited. We hypothesized women with greater exposure to uncomplicated common infectious events had an increased risk of subclinical cardiovascular disease (sCVD).

METHODS

In a cross-sectional study, we assessed the relation of recurrent infections and carotid artery intima-media thickness (IMT) in 1946 disease-free women from the Mexican Teachers' Cohort. Through 2012-2016, participants answered structured questions on respiratory, urinary and vaginal infections during the previous year and their IMT was measured using ultrasound by standardized neurologists. We defined sCVD as mean right and left IMT ≥0.8 mm or the presence of atheromatous plaque. Multivariable linear and logistic regression analyses were used to evaluate the association of infectious events with IMT and sCVD adjusting for age, sociodemographic, and cardiovascular risk factors.

RESULTS

Among participants (50±5 years) 13% reported no infections, 20% one infection and 67% three or more episodes. Overall prevalence of sCVD was 12%(n = 240). Adjusted models for logistic regression showed that women with 2 or more infections had 91% higher odds of sCVD (OR 1.91; 95%CI 1.16, 3.13) compared to women without infections (p-trend:0.015). Sub-analyses by type of infection resulted not significant. Linear regression analysis did not show a significant association between mean IMT and recurrent infections.

CONCLUSIONS

Recurrent infectious events in young adult women are associated with greater sCVD, which supports the hypothesis of low-grade chronic inflammation in the pathophysiology of cardiovascular disease.

The Microbiota Promotes Arterial Thrombosis in Low-Density Lipoprotein Receptor-Deficient Mice

Atherosclerotic plaque development depends on chronic inflammation of the arterial wall. A dysbiotic gut microbiota can cause low-grade inflammation, and microbiota composition was linked to cardiovascular disease risk. However, the role of this environmental factor in atherothrombosis remains undefined. To analyze the impact of gut microbiota on atherothrombosis, we rederived low-density lipoprotein receptor-deficient (Ldlr^-/- ) mice as germfree (GF) and kept these mice for 16 weeks on an atherogenic high-fat Western diet (HFD) under GF isolator conditions and under conventionally raised specific-pathogen-free conditions (CONV-R). In spite of reduced diversity of the cecal gut microbiome, caused by atherogenic HFD, GF Ldlr^-/- mice and CONV-R Ldlr^-/- mice exhibited atherosclerotic lesions of comparable sizes in the common carotid artery. In contrast to HFD-fed mice, showing no difference in total cholesterol levels, CONV-R Ldlr^-/- mice fed control diet (CD) had significantly reduced total plasma cholesterol, very-low-density lipoprotein (VLDL), and LDL levels compared with GF Ldlr^-/- mice. Myeloid cell counts in blood as well as leukocyte adhesion to the vessel wall at the common carotid artery of GF Ldlr^-/- mice on HFD were diminished compared to CONV-R Ldlr^-/- controls. Plasma cytokine profiling revealed reduced levels of the proinflammatory chemokines CCL7 and CXCL1 in GF Ldlr^-/- mice, whereas the T-cell-related interleukin 9 (IL-9) and IL-27 were elevated. In the atherothrombosis model of ultrasound-induced rupture of the common carotid artery plaque, thrombus area was significantly reduced in GF Ldlr^-/- mice relative to CONV-R Ldlr^-/- mice. Ex vivo, this atherothrombotic phenotype was explained by decreased adhesion-dependent platelet activation and thrombus growth of HFD-fed GF Ldlr^-/- mice on type III collagen.IMPORTANCE Our results demonstrate a functional role for the commensal microbiota in atherothrombosis. In a ferric chloride injury model of the carotid artery, GF C57BL/6J mice had increased occlusion times compared to colonized controls. Interestingly, in late atherosclerosis, HFD-fed GF Ldlr^-/- mice had reduced plaque rupture-induced thrombus growth in the carotid artery and diminished ex vivo thrombus formation under arterial flow conditions.

Predictive value for cardiovascular events of common carotid intima media thickness and its rate of change in individuals at high cardiovascular risk - Results from the PROG-IMT collaboration

AIMS

Carotid intima media thickness (CIMT) predicts cardiovascular (CVD) events, but the predictive value of CIMT change is debated. We assessed the relation between CIMT change and events in individuals at high cardiovascular risk.

METHODS AND RESULTS

From 31 cohorts with two CIMT scans (total n = 89070) on average 3.6 years apart and clinical follow-up, subcohorts were drawn: (A) individuals with at least 3 cardiovascular risk factors without previous CVD events, (B) individuals with carotid plaques without previous CVD events, and (C) individuals with previous CVD events. Cox regression models were fit to estimate the hazard ratio (HR) of the combined endpoint (myocardial infarction, stroke or vascular death) per standard deviation (SD) of CIMT change, adjusted for CVD risk factors. These HRs were pooled across studies. In groups A, B and C we observed 3483, 2845 and 1165 endpoint events, respectively. Average common CIMT was 0.79mm (SD 0.16mm), and annual common CIMT change was 0.01mm (SD 0.07mm), both in group A. The pooled HR per SD of annual common CIMT change (0.02 to 0.43mm) was 0.99 (95% confidence interval: 0.95-1.02) in group A, 0.98 (0.93-1.04) in group B, and 0.95 (0.89-1.04) in group C. The HR per SD of common CIMT (average of the first and the second CIMT scan, 0.09 to 0.75mm) was 1.15 (1.07-1.23) in group A, 1.13 (1.05-1.22) in group B, and 1.12 (1.05-1.20) in group C.

CONCLUSIONS

We confirm that common CIMT is associated with future CVD events in individuals at high risk. CIMT change does not relate to future event risk in high-risk individuals.

Association of hepatitis B virus infection with decreased ischemic stroke

OBJECTIVES

Inflammatory processes (both infections and autoimmune diseases) may cause endothelial dysfunction and arterial atherosclerosis, subsequently increasing the risk of acute ischemic stroke (AIS). In this investigation, we analyzed the association between hepatitis B virus (HBV) infection and AIS risk.

METHODS

A Taiwan national insurance claims data set of 1,000,000 patients was used to extract 22,303 patients with HBV and 89,212 randomly selected sex- and age-matched controls from the beginning of 2000 to the end of 2006. Both groups were followed up until the appearance of AIS or the end of 2011. AIS risk was measured using the Cox proportional regression model.

RESULTS

After adjusting for the relevant covariates, the HBV group exhibited a lower AIS risk (adjusted hazard ratio [aHR] = 0.77, 95% confidence interval [CI]: 0.66-0.89) compared with the controls at the end of follow-up. Under the condition of no comorbidities, patients with HBV had a lower AIS risk compared with the controls (aHR = 0.65, 95% CI: 0.48-0.87). In 3 age-stratified subgroups, HBV was correlated with a significantly diminished risk of AIS (age ≤ 49 years: aHR = 0.57, 95% CI: 0.39-0.82; age 50-64 years: aHR = 0.65, 95% CI: 0.53-0.80; age ≥ 65 years: aHR = 0.96, 95% CI: 0.76-1.23).

CONCLUSION

HBV was correlated with a reduced risk of AIS development. Although a decrease in AIS risk was noted in the patients with HBV, preventing the development of AIS in this population warrants further attention.

Promoter polymorphism of the gene for CD14 receptor is not associated with sub-clinical carotid atherosclerosis in a community population

BACKGROUND

The monocyte receptor CD14 is an important mediator of the inflammatory response to bacterial endotoxin. Recently, a functional polymorphism in the promoter of the CD14 gene (CD14-260C>T) was found to be associated with coronary heart disease. We examined if this polymorphism was associated with sub-clinical carotid atherosclerosis in a community population.

DESIGN AND METHODS

A randomly selected community population (557 men and 553 women; aged 27-77 years) underwent conventional risk factor assessment and ultrasound evaluation of the common carotid intima-medial wall thickness (IMT) and carotid plaque formation. CD14-260C>T genotypes were examined by restriction fragment length polymorphism analysis. Chlamydia pneumoniae-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) antibody titres were determined by micro-immunofluorescence.

RESULTS

The carrier frequency of the T allele and TT genotype was 0.48 and 0.22 respectively. Genotype frequencies met Hardy-Weinberg expectation. There was no significant association of -260C>T genotypes with traditional risk factors. On multivariate analysis, there was no independent association of genotypes with common carotid IMT in men and women or with prevalence of carotid plaque in women. Contrary to expectation, men who were TT homozygotes relative to CC wild-type had a lower adjusted risk of carotid plaque formation (odds ratio 0.34, 95% confidence interval 0.17-0.69; P=0.003). There was no evidence that smoking or C. pneumoniae infection modified the association of genotypes with carotid IMT or plaque formation.

CONCLUSION

The CD14-260C>T gene polymorphism was not associated with an increased risk of sub-clinical carotid atherosclerosis in a community population.

High Human Cytomegalovirus IgG Level is Associated with Increased Incidence of Diabetic Atherosclerosis in Type 2 Diabetes Mellitus Patients

Background

At present, whether human cytomegalovirus (HCMV) infection is associated with type 2 diabetes mellitus (T2DM) is debatable. The effect of active HCMV infection on glucose regulation has been poorly studied. Although HCMV infection is correlated with atherosclerosis in cardiovascular disease, the role of HCMV infection in the development of diabetic atherosclerosis in T2DM is unclear and is usually neglected by endocrinologists. The aim of this study was to assess the effects of HCMV infection on glucose regulation and the development of diabetic atherosclerosis in T2DM patients.

Material/Methods

A total of 222 hospitalized T2DM patients were enrolled. Nested polymerase chain reactions were used to detect HCMV DNA extracted from peripheral blood leukocytes. Quantitative real-time PCR was used to determine viral load. HCMV IgG antibody concentrations were analyzed by chemiluminescence immunoassay.

Results

HCMV active infection, viral load, and HCMV IgG titers were not correlated with glucose regulation. Binary logistic regression demonstrated that the highest quartile of HCMV IgG concentration (>500 U/ml) was correlated with the incidence of diabetic atherosclerosis (OR: 8.0, 95%CI: 2.3–27.2), and that titer >127U/ml of HCMV IgG is an independent predictor for the development of diabetic atherosclerosis in T2DM patients (OR: 4.6, 95%CI: 1.9–11.3) after adjustment for all potential confounding factors.

Conclusions

Active HCMV infection is unlikely to influence glucose regulation in T2DM. However, HCMV IgG titers are associated with the incidence of diabetic atherosclerosis, and titer >127U/ml of HCMV IgG might be an independent risk factor for the development of diabetic atherosclerosis in T2DM patients.

Virologic correlates of anti-CMV IgG levels in HIV-1-infected men

In human immunodeficiency virus (HIV)-infected individuals, higher levels of anti-cytomegalovirus (CMV) immunoglobulin G (IgG) antibody have been associated with increased immune activation, increased HIV transmission, cardiovascular complications, and neurocognitive impairment. However, the mechanism of these observations is unknown. This analysis of 228 HIV-infected men found that higher CMV IgG levels were positively associated with older age and antiretroviral treatment. Higher frequency of detectable CMV in peripheral blood mononuclear cells and recurrent seminal CMV reactivations were associated with lower plasma CMV IgG levels, suggesting that immune response to CMV rather than direct effect of viral replication is likely responsible for adverse clinical outcome observed in other studies.

Supra-additive expression of interleukin-6, interleukin-8 and basic fibroblast growth factor in vascular smooth muscle cells following coinfection with Chlamydia pneumoniae and cytomegalovirus as a novel link between infection and atherosclerosis

BACKGROUND

Chlamydia pneumoniae and human cytomegalovirus (HCMV) may be involved in the pathogenesis of atherosclerosis. Prospective studies indicate an increased risk for cardiovascular events in patients with evidence of multiple infections.

OBJECTIVE

To determine whether there is a synergistic effect of coinfection with C pneumoniae and HCMV on expression of selected growth factors and cytokines.

METHODS

The production of interleukin (IL)-6, IL-8, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and 'regulated on activation normal T-cell expressed and secreted' (RANTES) was measured in coinfected aortic smooth muscle cells (AoSMC).

RESULTS

Using reverse transcription polymerase chain reaction and immunoassays, it was demonstrated that the expression of IL-6, IL-8, RANTES and bFGF was stimulated in a dose- and time-dependent fashion in C pneumoniae and also in HCMV-infected cultures. In contrast, the expression of PDGF-AA was only stimulated following HCMV infection. Coinfection with C pneumoniae and HCMV resulted in a supra-additive stimulation of IL-6 (30% increased expression, P≤0.05) at 48 h, IL-8 (137% increased expression, P≤0.001) at 24 h and bFGF (209% increased expression, P≤0.01) at 48 h following infection.

CONCLUSIONS

The findings of the present study show that C pneumoniae and HCMV are able to act in synergy in coinfected AoSMC. The supra-additive induction of AoSMC growth factors and cytokines indicates a novel molecular link between infection and vascular disease development.

Increased carotid intima-media thickness associated with antibody responses to varicella-zoster virus and cytomegalovirus in HIV-infected patients

Objective

We investigated the relationship of the Herpesviridiae with inflammation and subclinical atherosclerosis in HIV-infected patients.

Methods

Prospective study including virologically suppressed HIV-infected patients. IgG antibodies against herpesviruses, carotid intima-media thickness (cIMT), endothelial function through flow-mediated dilatation (FMD) of the brachial artery, and blood atherosclerosis biomarkers (hsCRP, TNF-α, IL-6, MCP-1, MDA, sCD14, sCD163, VCAM-1, ICAM-1, D-dimer, and PAI-1) were measured.

Results

136 patients with HIV viral load <200 copies/ml were included. 93.4% patients were infected with herpes simplex virus type-1, 55.9% with herpes simplex virus type-2, 97.1% with varicella-zoster virus, 65.4% with human herpesvirus-6, 91.2% with cytomegalovirus, and 99.3% with Epstein-Barr virus. Previous AIDS diagnosis was associated with higher cytomegalovirus IgG titers (23,000 vs 17,000 AU, P = 0.011) and higher varicella-zoster virus IgG titers (3.19 vs 2.88 AU, P = 0.047), and there was a positive correlation of the Framingham risk score with IgG levels against cytomegalovirus (Spearman's Rho 0.216, P = 0.016) and Herpes simplex virus-2 (Spearman's Rho 0.293, P = 0.001). IgG antibodies against cytomegalovirus correlated in adjusted analysis with the cIMT (P = 0.030). High seropositivity for varicella-zoster virus (OR 2.91, 95% CI 1.05–8.01, P = 0.039), and for cytomegalovirus (OR 3.79, 95% CI 1.20–11.97, P = 0.023) were predictors for the highest quartile of the cIMT in adjusted analyses. PAI-1 levels were independently associated with cytomegalovirus IgG titers (P = 0.041), IL-6 and ICAM-1 levels with varicella-zoster virus IgG (P = 0.046 and P = 0.035 respectively), and hsCRP levels with Herpes simplex virus-2 IgG (P = 0.035).

Conclusion

In virologically suppressed HIV-infected patients, antibody responses against herpesviruses are associated with subclinical atherosclerosis, and with increased inflammation and coagulation biomarkers.

Cytomegalovirus seropositivity is associated with increased arterial stiffness in patients with chronic kidney disease

BACKGROUND

Patients with chronic kidney disease have an increased cardiovascular risk that is not fully explained by traditional risk factors but appears to be related to increased arterial stiffness. Cytomegalovirus (CMV) infection is associated with increased cardiovascular risk although the mechanisms for this are unknown. We examined whether CMV seropositivity was associated with increased arterial stiffness in patients with chronic kidney disease.

METHODOLOGY AND PRINCIPAL FINDINGS

In 215 non-diabetic patients with chronic kidney disease, CMV seropositivity was determined using an anti-CMV IgG ELISA. Pulse wave velocity was measured and aortic distensibility assessed in the ascending, proximal descending and distal descending thoracic aorta. Patients seropositive for CMV had a higher pulse wave velocity and lower aortic distensibility at all 3 levels. These differences (except for ascending aortic distensibility) persisted in a subcohort matched for age, gender and renal function, and when the whole cohort was divided into quartiles of age. In multivariable analyses, CMV seropositivity was an independent determinant of pulse wave velocity and proximal and distal descending aortic distensibility.

CONCLUSIONS

In patients with chronic kidney disease, CMV seropositivity is associated with increased arterial stiffness and decreased distensibility of the proximal descending and distal aorta. These findings suggest that further research is required to examine CMV as a possible cause of arterial disease and increased cardiovascular risk in patients with CKD and may be relevant more widely for CMV seropositive patients with normal renal function.

Cytomegalovirus immunoglobulin G antibody is associated with subclinical carotid artery disease among HIV-infected women

BACKGROUND

Cytomegalovirus (CMV) infection has been implicated in immune activation and accelerated progression of immunodeficiency from human immunodeficiency virus (HIV) coinfection. We hypothesized that CMV is associated with vascular disease in HIV-infected adults.

METHODS

In the Women's Interagency HIV Study, we studied 601 HIV-infected and 90 HIV-uninfected participants. We assessed the association of CMV immunoglobulin G (IgG) level with carotid artery intima-media thickness, carotid artery distensibility, Young's elastic modulus, and blood pressures. Multivariable models adjusted for age, race/ethnicity, smoking, diabetes, and body mass index.

RESULTS

Mean CMV IgG levels were higher in HIV-infected women compared with HIV-uninfected women (P < .01). Among HIV-infected women, higher CMV IgG level was associated with decreased carotid artery distensibility (P < .01) and increased Young's modulus (P = .02). Higher CMV IgG antibody level was associated with increased prevalence of carotid artery lesions among HIV-infected women who achieved HIV suppression on antiretroviral therapy, but not among viremic or untreated HIV-infected women. Adjustment for Epstein-Barr virus antibody levels and C-reactive protein levels had no effect on the associations between CMV IgG levels and vascular parameters.

CONCLUSIONS

Cytomegalovirus antibody titers are increased in HIV-infected women and associated with subclinical cardiovascular disease. Host responses to CMV may be abnormal in HIV infection and associated with clinical disease.

Pathogens and atherosclerosis: update on the potential contribution of multiple infectious organisms to the pathogenesis of atherosclerosis

It is currently unclear what causes the chronic inflammation within atherosclerotic plaques. One emerging paradigm suggests that infection with bacteria and/or viruses can contribute to the pathogenesis of atherosclerosis either via direct infection of vascular cells or via the indirect effects of cytokines or acute phase proteins induced by infection at non-vascular sites. This paradigm has been supported by multiple epidemiological studies that have established positive associations between the risk of cardiovascular disease morbidity and mortality and markers of infection. It has also been supported by experimental studies showing an acceleration of the development of atherosclerosis following infection of hyperlipidaemic animal models. There are now a large number of different infectious agents that have been linked with an increased risk of cardiovascular disease. These include: Chlamydia pneumoniae, Porphyromonas gingivalis, Helicobacter pylori , influenza A virus, hepatitis C virus, cytomegalovirus, and human immunodeficiency virus. However, there are significant differences in the strength of the data supporting their association with cardiovascular disease pathogenesis. In some cases, the infectious agents are found within the plaques and viable organisms can be isolated suggesting a direct effect. In other cases, the association is entirely based on biomarkers. In the following review, we evaluate the strength of the data for individual or groups of pathogens with regard to atherosclerosis pathogenesis and their potential contribution by direct or indirect mechanisms and discuss whether the established associations are supportive of the infectious disease paradigm. We also discuss the failure of antibiotic trials and the question of persistent infection.

Infectious burden: a new risk factor and treatment target for atherosclerosis

Atherosclerosis is a chronic inflammatory process, and several common bacterial and viral infections have been hypothesized to contribute to the inflammation of the vascular wall that leads to atherosclerosis. More recently, investigators have found preliminary evidence that the aggregate burden of these chronic infections, rather than any single organism, may contribute to atherosclerosis and risk of clinical vascular events, including ischemic stroke. This aggregate burden of infections, which has been variably labeled "infectious burden" or "pathogen burden," may be associated with stroke through mechanisms independent of atherosclerosis, as well, including platelet aggregation and endothelial dysfunction. Host factors, moreover, may interact with infectious burden to modify the risk of disease associated with these infections. Currently there is no commonly accepted group of organisms or method of assessing infectious burden, and not all studies confirm an association of infection and stroke risk. Nonetheless, if infectious burden does play a role in atherosclerosis or stroke, it is plausible that preventive anti-infective treatment, such as vaccination, or antibiotics, would reduce the risk of incident or recurrent stroke. While influenza vaccination has been recommended to prevent recurrence among those with coronary disease, similar recommendations for stroke patients have not yet been made. Large scale randomized clinical trials of macrolide antibiotics for coronary patients, moreover, have been negative. Further studies are needed, however, to determine whether an association between infectious burden and stroke exists, and whether infectious burden may be a target for intervention.

Common infections and the risk of stroke

The occurrence of stroke in populations is incompletely explained by traditional vascular risk factors. Data from several case-control studies and one large study using case series methodology indicate that recent infection is a temporarily acting, independent trigger factor for ischemic stroke. Both bacterial and viral infections, particularly respiratory tract infections, contribute to this association. A causal role for infection in stroke is supported by a graded temporal relationship between these conditions, and by multiple pathophysiological pathways linking infection and inflammation, thrombosis, and stroke. Furthermore, observational studies suggest that influenza vaccination confers a preventive effect against stroke. Case-control and prospective studies indicate that chronic infections, such as periodontitis, chronic bronchitis and infection with Helicobacter pylori, Chlamydia pneumoniae or Cytomegalovirus, might increase stroke risk, although considerable variation exists in the results of these studies, and methodological issues regarding serological results remain unresolved. Increasing evidence indicates that the aggregate burden of chronic and/or past infections rather than any one single infectious disease is associated with the risk of stroke. Furthermore, genetic predispositions relating to infection susceptibility and the strength of the inflammatory response seem to co-determine this risk. Here, we summarize and analyze the evidence for common acute and chronic infectious diseases as stroke risk factors.

Inflammatory mechanisms of stroke

Basic and clinical research provides evidence that inflammatory mechanisms play a central role in the pathogenesis and progression of atherosclerosis, plaque rupture, thrombosis, and stroke. Inflammatory biomarkers such as high-sensitivity C-reactive protein have been identified as predictors of first stroke and prognosis after stroke. The value of high-sensitivity C-reactive protein and other markers may depend on the characteristics of the study population; their utility may be less among populations with high vascular risk. A recent randomized, clinical trial suggests that the use of rosuvastatin therapy in otherwise healthy patients with high-sensitivity C-reactive protein >2 mg/dL can reduce the risk of a first stroke by 50%. The prognostic role of high-sensitivity C-reactive protein among patients after stroke, however, is less clear, and other biomarkers, including lipoprotein-associated phospholipase A(2), may provide complementary information about the risk of stroke recurrence. Infections, moreover, may contribute to inflammation and stroke risk. Although no single infectious organism is likely to be identified as the direct cause of atherosclerosis, summary measures of multiple chronic infectious exposures, or "infectious burden," have been associated with the risk of stroke and atherosclerosis affecting the carotid arteries. Acute infections have also been found to serve as stroke triggers in epidemiologic studies. Recommendations to vaccinate patients with cardiovascular disease against influenza represent the first specific anti-infective strategy to be used in vascular prophylaxis. Further studies are needed to determine the role of treatment of inflammation and infection in stroke prevention.

Prevalence of Chlamydophila pneumoniae is higher in aorta and coronary artery than in carotid artery of coronary artery disease patients

Coronary artery disease (CAD) is a public health problem accounting for an estimated one-third of deaths overall. A potential link between infectious agents and atherosclerosis has been suggested. Data obtained from several seroepidemiological studies have suggested that infection with Chlamydophila pneumoniae, Helicobacter pylori, cytomegalovirus and herpes simplex virus-1 can initiate or maintain the atherosclerotic process. However, there is no single study in which multiple infectious agents have been detected together in different vascular locations in the same population. This would help in determining if there is any leading pathogen in atheromatous plaques of CAD patients. Hence, we screened for C. pneumoniae, H. pylori, CMV and HSV-1 in different vascular locations of CAD patients using quantitative real-time (RT) PCR. We performed multiplex RT-PCR for detecting pathogens, viz. C. pneumoniae, H. pylori, CMV and HSV-1 in different vascular locations of CAD patients. Percent positivity scores for C. pneumoniae, H. pylori, CMV and HSV-1 in different vascular locations were as follows: aorta (64.7, 35.3, 11.7 and 11.7 respectively); carotid (27.2, 27.2, 9 and 0 respectively); coronary artery (58.3, 33.3, 16.6 and 8.3 respectively). Combined positivity for C. pneumoniae (C. pneumoniae IgA and RT-PCR for C. pneumoniae) was the highest compared with all other groups. Aorta and coronary artery were more susceptible to these pathogens as compared with carotid artery. Moreover, CAD patients' characteristics were associated with C. pneumoniae positivity (C. pneumoniae IgA and RT-PCR), suggesting thereby that C. pneumoniae may have caused chronic persistent infection in CAD.

Asymptomatic carotid plaque and pro-inflammatory genetic profile in the elderly

BACKGROUND AND AIMS

Several indices of subclinical atherosclerosis (ATS), including ultrasound (US) scan of carotid vessels, have received attention in clinical studies of the general population. Since inflammation takes part in the development of ATS, we studied the relationship between US imaging of carotid vessels and genetic predisposition to inflammation, in both elderly subjects without acknowledged CV risk factors and elderly subjects with acknowledged CV risk factors undergoing primary prevention.

METHODS

Seventy-two elderly subjects (aged between 65-84) were divided into three groups on the basis of cardiovascular (CV) risk (G0: 0-9%, G1: 10-20% and G2: >20%) according to the NCEP Adult Panel III Report. They underwent US evaluation of carotid arteries and were analyzed for single nucleotide polymorphisms in the genes of a number of cytokines: TNF-alpha, TGF-beta1, IL-10, IL-6 and IFN-gamma.

RESULTS

Asymptomatic carotid plaque (ACP) was detected in 19 subjects, not only in those belonging to the major risk group (36.8%) but also in those at lower risk (63.2%). In these subjects, we found a different genotype distribution in the polymorphisms of IFN-gamma (+874), IL-6 (-174) and IL- 10 (-1082). The TT +874 IFN-gamma and GG -174 IL-6 high producer-genotypes and the AA IL-10 low producergenotype were indeed more frequent in the ACP group (IFN-gamma: p=0.000 and IL-6: p=0.004). We found no correlation between genotype and carotid intima-media thickening.

CONCLUSIONS

Our data suggest that, in the elderly, inflammation-associated polymorphisms are related to atherogenesis and that the finding of ACP on US scan can be valuable in identifying subjects at risk for CV events, even if they lack traditional cardiovascular risk factors such as an increase in IMT.

Complexo miointimal das carótidas comum e interna em portadores de esquistossomose mansônica hepatoesplênica

OBJETIVO: Avaliar a espessura do complexo miointimal (IMT) das carótidas comum e interna, em portadores de esquistossomose hepatoesplênica (EHE) não tratados cirurgicamente, já submetidos a cirurgia para descompressão do sistema porta por esplenectomia e ligadura da veia gástrica esquerda, e comparar com volutários de condições sócio-econômico-ambientais similares, não portadores de esquistossomose. MÉTODOS: Utilizando aparelho de ultra-som Doppler de 7,5MHz foram mensurados os IMT de três grupos de voluntários, de ambos os gêneros, com idades que variaram de 20 a 60 anos, sendo avaliados os IMT máximos, IMT médios, IMT mínimos e seus desvios-padrão, das carótidas comuns e internas e feitas as comparações entre os grupos e suas associações com fatores de risco: idade, hipertensão arterial e tabagismo. RESULTADOS: Não houve diferença significante na média dos IMT, entre os lados direito e esquerdo e nem entre os grupos. Nos pacientes tratados cirurgicamente, assim como nos indivíduos-controle confirmou-se a associação, já conhecida, com os fatores de risco para aterosclerose (idade, hipertensão arterial e tabagismo). Contudo, não se observou este comportamento nos pacientes não operados. CONCLUSÃO: A EHE sem tratamento cirúrgico parece conferir "alguma proteção" contra a aterogênese em seres humanos; todavia, os achados não dão suporte definitivo a esta hipótese.

Persistent pathogens linking socioeconomic position and cardiovascular disease in the US

BACKGROUND

Numerous studies have documented a strong inverse association between cardiovascular disease and socioeconomic position (SEP). Several infections are associated with both cardiovascular disease and SEP; hence infection may form an important link between SEP and cardiovascular disease. This study examines whether seropositivity to cytomegalovirus (CMV), to herpes simplex virus type-1 (HSV-1), and/or to both pathogens mediates the relationship between SEP and cardiovascular disease history in a nationally representative sample of the United States.

METHODS

We conducted a cross-sectional study of subjects > or =45 years of age, who were tested for seropositivity to CMV, HSV-1 or both pathogens and assessed for cardiovascular disease history in the National Health and Nutrition Examination Survey III. Cardiovascular disease history was defined as history of stroke, heart attack and/or congestive heart failure and SEP as education level.

RESULTS

SEP was associated with CMV, HSV-1 and seropositivity to both pathogens. CMV seropositivity was associated with cardiovascular disease history even after adjusting for confounders as well as SEP. The odds of reporting a history of cardiovascular disease for those with less than a high school education compared with those with more than a high school education decreased by 7.7% after adjusting for CMV (Sobel mediation test for CMV, P = 0.0006). In contrast, neither seropositivity to HSV-1 nor to both pathogens was associated with cardiovascular disease history after adjusting for SEP.

CONCLUSIONS

Persistent pathogens such as CMV infection may explain a portion of the relationship between SEP and cardiovascular disease in the United States. Further studies examining additional pathogens and sociobiological mechanisms are warranted.

Limited role for C. pneumoniae, CMV and HSV-1 in cerebral large and small vessel atherosclerosis

Aims: To explore whether Chlamydia pneumoniae, Cytomegalovirus and Herpes Simplex Virus type 1 could be detected in large and small cerebral arteries, as well as in an area of brain parenchyma where white matter lesions (leukoaraiosis) can be found, in patients with clinically unmanifested cerebrovascular atherosclerosis. Methods and results( Arterial specimens from the basilar artery and middle cerebral artery, and brain samples from the basal ganglia and periventricular white matter were obtained. Neuropathological changes were assessed in Haematoxylin-Eosin stained sections. Polymerase chain reaction (PCR) was performed on paraffin embedded sections. Subsequently, we performed immunohistochemical staining on samples, which were found positive in PCR. We failed to detect C. pneumoniae, CMV, or HSV-1, in any of the cerebral large vessels. In the brain tissue, we found only one case positive for CMV, and one for C. pneumoniae. Conclusions (our findings suggest a limited role for C. pneumoniae, CMV and HSV-1 in cerebral large and small vessel atherosclerosis.

Lack of association between infectious burden and carotid atherosclerosis in Japanese patients

Several infectious agents, such as Chlamydia pneumoniae, cytomegalovirus (CMV), herpes simplex virus (HSV), and Helicobacter pylori, have been implicated in the pathogenesis of atherosclerosis; however, but the contribution of infection may vary among races and geographic conditions. The present study investigates the association between the presence of these pathogens and carotid atherosclerosis and examines the relevance of an infectious burden during atherogenesis in Japanese patients undergoing carotid endarterectomy. We investigated a total of 50 carotid atherosclerotic plaques resected during carotid endarterectomy by polymerase chain reaction (PCR) for C. pneumoniae, CMV, HSV, and H. pylori and by immunocytochemistry (ICC) for C. pneumoniae. We also examined the presence of antibodies to IgG and/or IgA for each pathogen in blood samples. We detected HSV DNA in 2 specimens (4%) and positive ICC for C. pneumoniae in 8 (16%). The results of PCR, ICC, or serum antibodies, as well as the number of seropositive antibodies, did not correlate with severely stenotic, ulcerative, or symptomatic plaques. Our findings indicate that the detection rate of infectious agents within atherosclerotic plaques was significantly lower in our patients than that in other studies. Thus, an inflammatory mechanism might not correlate with the pathogenesis of carotid atherosclerosis among Japanese patients with severe carotid artery stenosis.

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

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

Endothelial function parameters in patients with unstable angina and infection with Helicobacter pylori and Chlamydia pneumoniae

BACKGROUND

Endothelial dysfunction may be a factor linking infection with atherosclerosis. The aim of our study was to assess the relationship between seropositivity to Helicobacter pylori (Hp) and/or to Chlamydia pneumoniae (Cp) and some endothelial function parameters in patients with unstable angina.

METHODS

In 31 patients with unstable angina, we determined the serum concentration of the von Willebrand factor (vWF), thrombomodulin, tissue plasminogen activator antigen, and tissue plasminogen activator inhibitor type 1 antigen, the concentration of IgG antibodies to Hp and Cp (all by ELISA), and the level of C-reactive protein. The Western blot test was performed for all patients seropositive to Hp. It allowed us to identify 15 different antigen proteins of Hp.

RESULTS

Sixty-one percent of the patients were seropositive to both Hp and Cp, and 35% were seropositive to Hp only. We did not find significant differences in serum concentrations of endothelial function parameters and CRP between the two groups of patients. The patients seropositive to both Hp and Cp had a significantly higher serum concentration of vWF when Hp did not contain the 95 kDa protein (p=0.01) and a significantly higher serum concentration of PAI-1:Ag when Hp did not contain the 57 kDa protein (p=0.002) and the 66 kDa protein (p=0.02).

CONCLUSION

The results show that the antigenic profile of bacteria may play a more significant role in coronary artery disease than seropositivity.

Asymptomatic carotid lesions and aging: Role of hypertension and other traditional and emerging risk factors

BACKGROUND

We evaluated the prevalence of intima-media thickening (IMT) and asymptomatic carotid plaque (ACP) in a group of subjects with or without traditional and/or emerging risk factors (RF).

METHODS

There were 631 subjects (313 male and 318 female) aged between 19 and 97 years, asymptomatic for cerebro- and cardiovascular diseases. The following measurements were used: anamnesis, physical examination, height and sitting blood pressure. Biochemistry variables were also considered: total cholesterol, HDL-C, LDL-C, triglycerides, fibrinogen, high sensitive C-reactive protein, IgG antibodies for Helicobacter pylori (HP), cytotoxic HP, cytomegalovirus and Chlamydia pneumoniae. Finally, an echo color Doppler examination of the carotid arteries was performed. We subdivided the population studied in normotensive and hypertensive subjects and evaluated in each group the frequency of IMT and ACP in relation to age.

RESULTS

We showed that IMT + ACP was significantly more frequent in patients >65 years in comparison with those <65 years (80.6 vs. 52.1%, p < 0.005) and in hypertensive patients in comparison to normotensive, independent of coexistence of other cardiovascular risk factors (71 vs. 48%, p < 0.005). Another interesting result of our study is a significant presence of IMT and ACP in subjects with emerging but without traditional RF than in subjects with traditional but without emerging RF.

CONCLUSIONS

IMT and ACP of carotid arteries are significantly more frequent in patients >65 years vs. those <65 years and in hypertensive patients in comparison to controls. Finally, we have found that the seropositivity of infection and the presence of higher levels of marker of inflammation were correlated with carotid lesion.

Cross-reactivity of GroEL antibodies with human heat shock protein 60 and quantification of pathogens in atherosclerosis

BACKGROUND/AIMS

Chronic infections such as those caused by Chlamydia pneumoniae and periodontopathic bacteria such as Porphyromonas gingivalis have been associated with atherosclerosis, possibly due to cross-reactivity of the immune response to bacterial GroEL with human heat shock protein (hHSP) 60.

METHODS

We examined the cross-reactivity of anti-GroEL and anti-P. gingivalis antibodies with hHSP60 in atherosclerosis patients and quantified a panel of six pathogens in atheromas.

RESULTS

After absorption of plasma samples with hHSP60, there were variable reductions in the levels of anti-GroEL and anti-P. gingivalis antibodies, suggesting that these antibodies cross-reacted with hHSP60. All of the artery specimens were positive for P. gingivalis. Fusobacterium nucleatum, Tannerella forsythia, C. pneumoniae, Helicobacter pylori, and Haemophilus influenzae were found in 84%, 48%, 28%, 4%, and 4% of arteries, respectively. The prevalence of the three periodontopathic microorganisms, P. gingivalis, F. nucleatum and T. forsythia, was significantly higher than that of the remaining three microorganisms.

CONCLUSIONS

These results support the hypothesis that in some patients, cross-reactivity of the immune response to bacterial HSPs including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may be a possible mechanism for the association between atherosclerosis and periodontal infection.

Chronic cytomegalovirus infection and inflammation are associated with prevalent frailty in community-dwelling older women

OBJECTIVES

To evaluate the association between asymptomatic chronic cytomegalovirus (CMV) infection and the frailty syndrome and to assess whether inflammation modifies this association.

DESIGN

Cross-sectional analysis.

SETTING

Women's Health and Aging Study I & II, Baltimore, Maryland.

PARTICIPANTS

Seven hundred twenty-four community-dwelling women aged 70 to 79 with baseline measures of CMV, interleukin-6 (IL-6), and frailty status.

MEASUREMENTS

CMV serology and IL-6 concentrations were measured using enzyme-linked immunosorbent assay. Frailty status was based on previously validated criteria: unintentional weight loss, weak grip strength, exhaustion, slow walking speed, and low level of activity. Frail women had three or more of the five components, prefrail women had one or two components, and women who were not frail had none of the components. Multinomial logistic regression adjusted for potential confounders.

RESULTS

Eighty-seven percent of women were CMV seropositive, an indication of chronic infection. CMV was associated with prevalent frailty, adjusting for age, smoking history, elevated body mass index, diabetes mellitus, and congestive heart failure (CMV frail adjusted odds ratio (AOR)=3.2, P=.03; CMV prefrail AOR=1.5, P=.18). IL-6 interacted with CMV, significantly increasing the magnitude of this association (CMV positive and low IL-6 frail AOR=1.5, P=.53; CMV positive and high IL-6 frail AOR=20.3, P=.007; CMV positive and low IL-6 prefrail AOR=0.9, P=.73; CMV positive and high IL-6 prefrail AOR=5.5, P=.001).

CONCLUSION

Chronic CMV infection is associated with prevalent frailty, a state with increased morbidity and mortality in older adults; inflammation enhances this effect. Further prospective studies are needed to establish a causal relationship between CMV, inflammation, and frailty.

The pathogenesis of atherosclerosis

Worldwide, more people die of the complications of atherosclerosis than of any other cause. It is not surprising, therefore, that enormous resources have been devoted to studying the pathogenesis of this condition. This article attempts to summarize present knowledge on the events that take place within the arterial wall during atherogenesis. Classical risk factors are not dealt with as they are the subjects of other parts of this book. First, we deal with the role of endothelial dysfunction and infection in initiating the atherosclerotic lesion. Then we describe the development of the lesion itself, with particular emphasis on the cell types involved and the interactions between them. The next section of the chapter deals with the events leading to thrombotic occlusion of the atherosclerotic vessel, the cause of heart attack and stroke. Finally, we describe the advantages--and limitations--of current animal models as they contribute to our understanding of atherosclerosis and its complications.

C-reactive protein levels and prevalence of chronic infections in subjects with hypoalphalipoproteinemia

Low levels of high-density lipoprotein cholesterol (HDL-C) show a consistent relationship with the development of atherosclerosis. The underlying mechanisms are not well understood, but recent studies in subjects with primary hypoalphalipoproteinemia suggest that this could represent a proinflammatory condition. To better assess the link between HDL-C levels and C-reactive protein levels and the possible role of chronic infections as putative mediators of this relationship, we studied a population sample with nonselected causes of hypoalphalipoproteinemia. Eighty-six consecutive patients with HDL-C levels below 40 mg/dL who attend our lipid clinic and 86 control subjects with normal concentrations matched for gender, age, smoking habit, and weight were included in the study. Mean HDL-C levels were 34 +/- 3.9 and 55.4 +/- 8.8 mg/dL for subjects with hypoalphalipoproteinemia and control subjects, respectively. C-reactive protein concentrations were increased in case patients as compared with control subjects (2.13 +/- 2.0 vs 1.52 +/- 1.8 mg/L; P = .025). The prevalence of herpes simplex virus type 1, cytomegalovirus, Chlamydia pneumoniae , and Helicobacter pylori infections did not differ between the 2 groups. Although a possible confounding variable could be a degree of insulin resistance within the group of patients with low HDL-C levels, our results indicate that C-reactive protein levels are increased in subjects with nonselected hypoalphalipoproteinemia and that chronic infections do not appear to mediate this relationship.

Soluble CD14 and aortic stiffness in a population-based study

OBJECTIVE

Soluble CD14 (sCD14), an effective mediator for the activation of monocytes by bacterial endotoxin is involved in the release of substances able to modify the characteristics of the arterial wall. The aim of this study was to investigate, in humans, the relationship of sCD14 with aortic stiffness and to analyse the influence of arterial structure and endothelial function on this relationship.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

One thousand and fifteen subjects randomly selected from the polling lists, were recruited by the Toulouse MONICA centre between 1995 and 1997.

METHODS

Carotid-femoral pulse wave velocity (PWV) and blood pressure (BP) were measured in the supine position. Common carotid intima-media thickness (IMT) and the presence of plaques were assessed by ultrasonography. sCD14 was measured using an immunoenzymatic method.

RESULTS

The results concern the 891 subjects with complete data for all the variables. In the bivariate analyses, PWV (P < 0.001), systolic BP (P < 0.05), pulse pressure (PP) (P < 0.01), IMT (P < 0.001), the number of plaques (P < 0.05) and von Willebrand factor activity (vWFa) (P < 0.001) were positively associated with sCD14, whereas no significant relationship was observed between sCD14 and diastolic BP. After adjustment for age and sex, no significant relationship remained between IMT, the number of plaques, SBP, PP and sCD14. A significant and positive relationship was observed between sCD14 and PWV (trend P < 0.05) after adjustment for numerous confounders.

CONCLUSION

This population-based study yields first evidence that sCD14 is associated with aortic stiffness independently of age, BP and atherosclerosis in humans.

Chronic infection and coronary artery disease

On a variety of fronts, chronic infection has been found to be significantly associated with the development of atherosclerosis and the clinical complications of unstable angina, myocardial infarction, and stroke. For the most part, these relationships are still just associations. Failure to confirm initial reports of serologic associations also has been common. Specific causative relationships on par with that determined between H pylori and peptic ulcer disease have not yet been established. Potential mechanisms whereby chronic infections may play a role in atherogenesis are myriad. In the case of C pneumoniae, the effect may result from direct vessel wall colonization that may damage the vessel either directly or indirectly by initiating immunologic responses. In other cases the effect may simply be that of enhancing the pre-existing chronic inflammatory response of the body to standard risk factors such as hyperlipidemia. Even though the infectious agent may not directly infect the vessel wall, it may perform its critical role from afar. Chronic infection might also influence pre-existing plaque by enhancing T-cell activation or other inflammatory responses that may participate in the destabilization of the intimal cap. Hence chronic infection may play a role either in the initiation, progression, or the destabilization of atherosclerotic plaques. The infectious agents with the most evidence to support an etiologic role in atherosclerosis include C pneumoniae and cytomegalovirus. Evidence is mounting for a variety of other potential agents including other herpes viruses, influenza, other specific bacteria (such as M pneumoniae), and chronic infections with common bacterial agents (periodontal disease, chronic bronchitis, and chronic urinary tract infection, among others) [191]. Future studies are expected to elucidate further the pathophysiologic relationship between chronic infection and atherosclerosis and to evaluate further the potential of a variety of treatment approaches, including antibiotics.

A link between Helicobacter pylori and/or Chlamydia spp. infections and atherosclerosis

Antibodies to Helicobacter pylori, Chlamydia spp. and Mycobacterium bovis were determined in patients with coronary heart disease, H. pylori-related dyspepsia, and tuberculosis, and healthy controls. Enzyme-linked immunosorbent assay was conducted with a glycine extract and CagA protein of H. pylori, chlamydial lipopolysaccharide and mycobacterial heat shock protein Hsp65. The prevalence of anti-glycine extract IgG in coronary heart disease patients was higher than in the tuberculosis group and controls, and the same as in dyspeptic patients. Anti-chlamydial IgG were more prevalent in the coronary heart disease group than in healthy subjects. There was no difference in the prevalence of anti-CagA IgG in the coronary heart disease group and controls or anti-Hsp65 IgG in the patients with coronary heart disease, dyspepsia, tuberculosis, and controls. Anti-glycine extract IgA (like anti-glycine extract IgG) were more prevalent in the coronary heart disease group than in the healthy group. The highest anti-glycine extract IgG/IgA and anti-chlamydial IgG titers were more frequent in coronary heart disease patients as compared with controls. Infections with H. pylori and Chlamydia spp. and enhanced production of antibodies to these pathogens may predispose to human atherosclerosis.

Lack of association between Chlamydia pneumoniae seropositivity and aortic atherosclerotic plaques: a population-based transesophageal echocardiographic study

OBJECTIVES

The objective of this study was to examine the relationship between Chlamydia pneumoniae seropositivity and aortic atherosclerotic plaques in the general population.

BACKGROUND

Seroepidemiologic studies suggest that C pneumoniae infection plays a role in the pathogenesis of atherosclerosis.

METHODS

Transesophageal echocardiography was performed in 385 subjects (median age 66 years, range 51 to 101 years; 53% men), a sample of the Olmsted County (Minnesota) population. The association between C pneumoniae immunoglobulin (Ig) G antibody titers and aortic atherosclerotic plaques was examined.

RESULTS

Chlamydia pneumoniae IgG antibodies (titers >or=1:16) were detected in 287 subjects (74.5%): low titers (1:16 to 1:32) in 58 (15.1%), intermediate titers (1:64 to 1:128) in 144 (37.4%), and high titers (>or=1:256) in 85 subjects (22.1%). Antibody titers were not associated with the presence of aortic plaques after adjustment for age, gender, and smoking status (p = 0.64). Compared with titers <1:16, the adjusted odds ratios for aortic plaques were 1.46 (95% confidence interval [CI] 0.63 to 3.42) for low titers, 1.32 (95% CI 0.68 to 2.55) for intermediate titers, and 0.94 (95% CI 0.42 to 2.07) for high titers. Among the subgroup with plaques, antibody titers were not associated with the presence of plaques >or=4 mm thick (p = 0.99), plaques >or=6 mm (p = 0.49), or mobile debris (p = 0.71), after adjustment for age and smoking.

CONCLUSIONS

Chlamydia pneumoniae IgG antibody titers are not associated with the presence or severity of aortic atherosclerosis in the general population. These observations do not support a role for C pneumoniae infection in the initiation or progression of atherosclerosis.

Early atherosclerosis and Chlamydia pneumoniae infection in the coronary arteries

In non-atheromatous segments of coronary arteries a sequence of preatherosclerotic changes was identified which consisted of medial thickening followed by intimal thickening. More recently, Chlamydia pneumoniae seropositivity was associated with enhanced intima-media thickness of arteries. In the present study the intimal and medial thickness of coronary artery of young adults were measured, and were correlated with the presence of Chlamydia pneumoniae antigens. Proximal and distal segments of the left anterior descending coronaries (LAD) obtained at autopsy from young adults (15-34 years) were studied. The thickness and cellular density of the intima and of the media without clear-cut atherosclerotic changes were measured by image analysis. The hypertrophy index was calculated as the ratio of cell density and the thickness of the respective layer. Atherosclerotic lesions occurring elsewhere in the same coronary were noted and graded by severity. The presence of Chlamydia pneumoniae verified by immunohistochemistry was correlated with the severity of lesions and with the hypertrophy index. In the proximal segments, atherosclerosis of LAD was associated with the widening of both the intima and the media of lesion free-sites. In the distal coronary segments the proportion of the intimal thickening had a significant association with atherosclerosis. Compared to non-infected arteries, Chlamydia pneumoniae infection was associated with higher hypertrophy index in the intima as well as in the media. The rate of Chlamydia pneumoniae positivity increased with the severity of lesions. As a conclusion: in the LAD coronary, the intimal thickening is the main preatherosclerotic change. Chlamydia pneumoniae may favour arterial wall hypertrophy and plays a role in lesion progression.

Chlamydia pneumoniae and acute chest syndrome in patients with sickle cell disease

PURPOSE Few studies address the association of Chlamydia pneumoniae infection with pulmonary disease and outcome in patients with underlying pathology such as sickle cell disease (SCD). SCD patients are susceptible to the pulmonary disorder known as acute chest syndrome (ACS), where the etiology remains ill defined. The purpose of this study was to analyze the clinical course and outcome of C. pneumoniae-associated ACS among SCD patients as part of the National Acute Chest Syndrome Study.

PATIENTS AND METHODS

This was a longitudinal study of SCD patients presenting with ACS to multiple U.S. medical centers. Two hundred ninety-six SCD patients who developed ACS were tested by PCR for C. pneumoniae and by standard techniques for other respiratory pathogens. These infections were evaluated for association with ACS, clinical course, and complications.

RESULTS

Forty-one (14%) patients with first episodes of ACS were PCR positive for C. pneumoniae. Compared with other infections, C. pneumoniae-infected patients were older, were more likely to present with chest pain, and had higher hemoglobin levels at diagnosis. Both groups had similar rates of respiratory failure and prolonged hospitalization. Of the 89 patients with single-pathogen infections, 27 (30%) were due to C. pneumoniae, 21% to Mycoplasma pneumoniae, 10% to RSV, 4% to Staphylococcus aureus, and 3% to Streptococcus pneumoniae.

CONCLUSIONS

C. pneumoniae was the most prevalent pathogen in this study of ACS and was responsible for significant morbidity. Additional research is required to develop effective treatment guidelines for ACS.

The relation between Helicobacter pylori and atherosclerosis cannot be explained by a high homocysteine concentration

BACKGROUND

Recent studies have suggested that a chronic infection with Helicobacter pylori might be an independent risk factor for atherosclerosis. However, a direct role in atherogenesis is not plausible, since the bacterium has not been isolated from atherosclerotic lesions. An indirect mechanism that could link H. pylori with atherosclerosis might be through an increase in plasma homocysteine concentration caused by deficiencies of vitamin B12 and folate in plasma.

MATERIALS AND METHODS

In 150 female patients with peripheral arterial disease (PAD) and in 412 healthy control women from a nation-wide population-based case-control study, blood samples were collected to determine the antibody titre against H. pylori and to measure plasma homocysteine, folate and vitamin B12 levels. First, the odds ratio for PAD in women with a positive antibody titre against H. pylori was calculated and adjusted for homocysteine level. Secondly, mean concentrations of vitamin B12, folate and homocysteine were compared in healthy controls with a positive or negative antibody titre against H. pylori. Thirdly, the relation between H. pylori and PAD in individuals with a normal or high homocysteine level was investigated.

RESULTS

A positive immunoglobulin G antibody titre against H. pylori was found in 42% of the PAD patients and in 27% of the controls. The age- and socio-economic-status (SES) adjusted odds ratio for PAD was 1.5 (95%CI; 1.0-2.2). Additional adjustment for homocysteine plasma concentration did not essentially change the odds ratio. Secondly, among the healthy controls, the homocysteine plasma concentration did not depend on the immunoglobulin G titre, neither did the folate plasma concentration. The concentration of vitamin B12 was slightly higher in women with a positive titre. Thirdly, H. pylori infection was a risk factor for PAD in subjects with a normal homocysteine concentration [OR 2.0 (95%CI 1.3-3.1)].

CONCLUSIONS

This study shows a relationship between a positive immunoglobulin G antibody titre against H. pylori and PAD in young women. Moreover, this study does not support the hypothesis that H. pylori infection is related to atherosclerosis via an increase in plasma homocysteine concentration.