Dual role of infections as risk factors for coronary heart disease

The rise and fall of tobacco smoking and associated rise and fall of coronary atherosclerosis the lethal role of tobacco

In this review two new hypotheses are explored, one, that the decline in coronary heart disease is mainly due to a dramatic decline in the prevalence of underlying atherosclerosis and two, that tobacco smoking has been a much greater influence on atherosclerosis than previously estimated. The major outcome of coronary atherosclerosis is myocardial infarction. Between 1900 and 1960 the prevalence of coronary atherosclerosis dramatically rose in young male soldiers. Between 1960 and 2010 the prevalence of coronary atherosclerosis in young US soldiers equally dramatically fell. Understanding the reasons for this rise and fall offers important insights into the causes of atherosclerosis. In 1960 over 50% of US military personnel were tobacco smokers but by 1988 the rate had reduced to 30%. The increased prevalence of coronary atherosclerosis in young soldiers between 1900 and 1960 was mainly due to increased tobacco smoking. An additional influence was an increase in food and sugar consumption. The fall in atherosclerosis between 1960 and 2010 was probably due to a reduction in tobacco smoking and to a lesser extent, control of hypertension and lowering of high serum total cholesterol. In Western populations up to two thirds of the fall in deaths due to myocardial infarction has been shown to be due to declines in the incidence of heart attacks. Based on the data included in this review it is arguable that the main reason for the fall in the incidence of heart attacks is the fall in the prevalence of underlying coronary atherosclerosis. The adverse influences of tobacco have been well documented. However the enormity of these adverse influences has not been recognised. Over 50% of men continue to smoke tobacco in China, Indonesia, Russia and middle eastern countries. Based on the experience of Western countries over half of these men will die of smoking related conditions.

Immune response to a conserved enteroviral epitope of the major capsid VP1 protein is associated with lower risk of cardiovascular disease

Background

Major cardiac events including myocardial infarction (MI) are associated with viral infections. However, how specific infections contribute to the cardiovascular insults has remained largely unclear.

Methods

We employed next generation phage display mimotope-variation analysis (MVA) to explore the link between antibody-based immune response and severe cardiovascular conditions. Here, we used a case-control design, including the first-stage discovery cohort (n = 100), along with cohorts for second-stage discovery (n = 329) and validation (n = 466).

Findings

We observed strong antibody response to the peptide antigens with Gly-Ile-X-Asp (G-I-X-D) core structure in healthy individuals but not in patients with MI. Analysis of the origin of this epitope linked it with the N-terminus of the VP1 protein of poliovirus 3 (PV3), but also other species of picornaviruses. Consistently, we found low levels of antibody response to the G-I-X-D epitope in individuals with severe cardiac disease complications.

Interpretation

Our findings imply that antibody response to the G-I-X-D epitope is associated with polio vaccinations and that high antibody levels to this epitope could discriminate healthy individuals from prospective MI patients as a blood-derived biomarker. Together, these findings highlight the importance of epitope-specific antibody response and suggest that protective immunity against the polio- and non-polio enteroviral infections support improved cardiovascular health.

Funding

Estonian Ministry of Education (5.1-4/20/170), Estonian Research Council (PRG573, PRG805), H2020-MSCA-RISE-2016 (EU734791), H2020 PANBioRA (EU760921), European Union through the European Regional Development Fund (Project no. 2014-2020.4.01.15-0012), Helsinki University Hospital grants, Mary and Georg C. Ehrnrooth Foundation, Finnish Eye Foundation, Finska Läkaresällskapet, The Finnish Society of Sciences and Letters, Magnus Ehrnrooth Foundation and Sigrid Jusélius Foundation.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Infection and food combine to cause atherosclerotic coronary heart disease - Review and hypothesis

Hypothesis

It is hypothesised that a combination of childhood and later life infections and excess food consumption, particularly of Western style food, initiates and contributes to atherosclerotic coronary heart disease. To consider this hypothesis we have conducted a brief review of the role of childhood infections, food, and their combined influence on atherosclerosis.

Evidence

(i) Studies of populations with high prevalence of infections and low “hunter gather” like food consumption, have extremely low prevalence of atherosclerosis, (ii) there are consistent associations between infections in childhood and adult atherosclerotic coronary heart disease, (iii) there is an association between increased body weight, (an indication of excess eating), and atherosclerotic heart disease, and (iv) there is evidence that a combination of increased body weight and infections influences the development of atherosclerotic coronary heart disease.

Infections do not appear to act independently to cause atherosclerosis. A combination of both food and infection appears to be required to cause atheroma.

Conclusion

The hypothesis that infections when combined with excess eating initiates atherosclerosis, is plausible.

Action

Action aimed at prevention of atherosclerotic heart disease is possible. There are three safe approaches to prevention (i) encouragement of Mediterranean like diets, (ii) avoidance of overeating and (iii) vigorous control of infections among all age groups. There is a need to monitor patients with a history of serious childhood infections and poor nutrition. In addition, for high risk subjects, cholesterol lowering statins are of proven and safe value.

Association of Childhood Oral Infections With Cardiovascular Risk Factors and Subclinical Atherosclerosis in Adulthood

IMPORTANCE

Severe forms of common chronic oral infections or inflammations are associated with increased cardiovascular risk in adults. To date, the role of childhood oral infections in cardiovascular risk is not known because no long-term studies have been conducted.

OBJECTIVE

To investigate whether signs of oral infections in childhood are associated with cardiovascular risk factors and subclinical atherosclerosis in adulthood.

DESIGN, SETTING, AND PARTICIPANTS

The cohort study (n = 755) was derived from the Cardiovascular Risk in Young Finns Study, an ongoing prospective cohort study in Finland initiated in 1980. Participants underwent clinical oral examinations during childhood, when they were aged 6, 9, or 12 years and a clinical cardiovascular follow-up in adulthood in 2001 at age 27, 30, or 33 years and/or in 2007 at age 33, 36, or 39 years. Cardiovascular risk factors were measured at baseline and during the follow-up until the end of 2007. Final statistical analyses were completed on February 19, 2019.

MAIN OUTCOMES AND MEASURES

Four signs of oral infections (bleeding on probing, periodontal probing pocket depth, caries, and dental fillings) were documented. Cumulative lifetime exposure to 6 cardiovascular risk factors was calculated from dichotomized variables obtained by using the area-under-the-curve method. Subclinical atherosclerosis (ie, carotid artery intima-media thickness [IMT]) was quantified in 2001 (n = 468) and 2007 (n = 489).

RESULTS

This study included 755 participants, of whom 371 (49.1%) were male; the mean (SD) age at baseline examination was 8.07 (2.00) years. In this cohort, 33 children (4.5%) had no sign of oral infections, whereas 41 (5.6%) had 1 sign, 127 (17.4%) had 2 signs, 278 (38.3%) had 3 signs, and 248 (34.1%) had 4 signs. The cumulative exposure to risk factors increased with the increasing number of oral infections both in childhood and adulthood. In multiple linear regression models, childhood oral infections, including signs of either periodontal disease (R2 = 0.018; P = .01), caries (R2 = 0.022; P = .008), or both (R2 = 0.024; P = .004), were associated with adulthood IMT. The presence of any sign of oral infection in childhood was associated with increased IMT (third tertile vs tertiles 1 and 2) with a relative risk of 1.87 (95% CI, 1.25-2.79), whereas the presence of all 4 signs produced a relative risk of 1.95 (95% CI, 1.28-3.00). The associations were more obvious in boys: if periodontal disease were present, the corresponding estimate was 1.69 (95% CI, 1.21-2.36); if caries, 1.46 (95% CI, 1.04-2.05); and if all 4 signs of oral infections, 2.25 (95% CI, 1.30-3.89). The associations were independent of cardiovascular risk factors.

CONCLUSIONS AND RELEVANCE

Oral infections in childhood appear to be associated with the subclinical carotid atherosclerosis seen in adulthood.

Adaptation to acute coronary syndrome-induced stress with lowering of testosterone: a possible survival factor

OBJECTIVE

The objective of this study was to explore whether circulating testosterone (T) concentration is associated with the occurrence and risk for acute coronary syndromes (ACS).

METHOD

This case-control study included male patients with acute myocardial infarction (AMI) (n=174) or unstable angina pectoris (UAP) (n=90) and healthy controls (n=238). Patients gave serum samples during the acute (n=264) and recovery (n=132) phases after a median of 10.5 months after the incident event. Secondary events (ACS or cardiovascular death) were registered during the following 6 years.

RESULTS

During the acute phase, AMI and UAP patients had similar significantly reduced concentrations of serum testosterone in comparison to controls. Testosterone associated inversely with weight, the degree of inflammation (i.e. C-reactive protein concentration) and signs of a chronic infection. In a multiadjusted Cox regression, when compared to testosterone concentrations considered high-normal (14.91-34.0  nmol/l), low-normal testosterone (9.26-14.90  nmol/l) in the acute phase predicted better prognosis for cardiovascular death rate with a hazard ratio (HR) of 0.17 (0.04-0.68, P=0.012). The increased testosterone concentrations after the recovery period did not associate with future cardiovascular disease events.

CONCLUSION

Low-normal testosterone levels in the acute phase of ACS predicted better survival. The observation may indicate better adaptation to stress in survivors and warrants further study.

A prospective study of the clinical characteristics of patients with herpes simplex and varicella zoster keratitis, presenting to a New Zealand emergency eye clinic

PURPOSE

To identify the demographic and clinical associations of patients presenting with herpetic keratitis in New Zealand compared with presentations of presumed microbial keratitis.

METHODS

A prospective, 6-month, observational case series of presumed microbial keratitis (including marginal keratitis), specifically identifying all cases of herpes simplex and varicella zoster keratitis attending an emergency eye clinic was conducted. Main outcome measures included demographics, presenting signs and symptoms, and medical, ocular, and drug history.

RESULTS

A total of 140 cases of herpetic keratitis were identified, which comprised 125 cases of herpes simplex virus (89%) and 15 cases of varicella zoster virus (11%). Herpes simplex keratitis was associated with a history of keratitis (n = 58, phi = 0.24, P < 0.0001), Maori ethnicity (n = 27, phi = 0.26, P < 0.0001), respiratory disease (n = 18, phi = 0.14, P = 0.009), corticosteroid use (n = 23, phi = 0.22, P < 0.0001), and cardiovascular disease (CVD) (n = 10, phi = 0.11, P = 0.03). Inverse association was observed between herpes simplex keratitis and ocular surface disease (n = 8, phi = -0.16, P < 0.002) and Asian ethnicity (n = 4, phi = -0.11, P = 0.04). Varicella zoster keratitis was associated with CVD (n = 3, phi = 0.15, P = 0.03).

CONCLUSIONS

Patients with asthma, CVD, on long-term corticosteroid inhalers or creams, or of Maori ethnicity need particular assessment to investigate herpes simplex as a possible cause of keratitis. Clinicians prescribing inhaled corticosteroids or topical corticosteroid creams should be aware of possible association with herpes simplex keratitis.

Association of measles and mumps with cardiovascular disease: The Japan Collaborative Cohort (JACC) study

OBJECTIVE

Although it has been suggested that exposure to infections during childhood could decrease risk of atherosclerotic cardiovascular disease (CVD), the evidence is scarce. We investigated the association of measles and mumps with CVD.

METHODS

43,689 men and 60,147 women aged 40-79 years at baseline (1988-1990) completed a lifestyle questionnaire, including their history of measles and mumps, and were followed until 2009. Histories of infections were categorized as having no infection (reference), measles only, mumps only, or both infections. Hazard ratios (HR) for mortality from CVD across histories of infections were calculated.

RESULTS

Men with measles only had multivariable HR (95% confidence interval) of 0.92 (0.85-0.99) for total CVD, those with mumps only had 0.52 (0.28-0.94) for total stroke and 0.21 (0.05-0.86) for hemorrhagic stroke, and those with both infections had 0.80 (0.71-0.90) for total CVD, 0.71 (0.53-0.93) for myocardial infarction, and 0.83 (0.69-0.98) for total stroke. Women with both infections had 0.83 (0.74-0.92) for total CVD and 0.84 (0.71-0.99) for total stroke. We also compared subjects with measles only or mumps only (reference) and those with both infections. Men with both infections had 0.88 (0.78-0.99) for total CVD. Women with both infections had 0.85 (0.76-0.94) for total CVD, 0.79 (0.67-0.93) for total stroke, 0.78 (0.62-0.98) for ischemic stroke and 0.78 (0.62-0.98) for hemorrhagic stroke.

CONCLUSIONS

Measles and mumps, especially in case of both infections, were associated with lower risks of mortality from atherosclerotic CVD.

Endothelial cell death and intimal foam cell accumulation in the coronary artery of infected hypercholesterolemic minipigs

Apoptosis of endothelial cells (ECs) has been suggested to play a role in atherosclerosis. We studied the synergism of hypercholesterolemia with Chlamydia pneumoniae and influenza virus infections on EC morphology and intimal changes in a minipig model. The coronary artery was excised at euthanasia (19 weeks of age) and serial sections were processed for the detection of EC apoptosis, histology, and transmission electron microscopy (TEM) studies. There was a significantly higher number of TUNEL-positive ECs in infected compared to noninfected groups [0.2942 % (interquartile ranges (IR), 0.2941; n = 26) versus 0 % (IR, 0; n = 12), p < 0.01]. Caspase-3 staining was negative. Cholesterol diet together with infections induced widening of the subendothelial space and appearance of increased numbers of foam cells. TEM revealed degenerative changes in cytoplasmic organelles and signs of EC necrosis. In conclusion, infection leads to an increase in coronary EC death and seems to exacerbate cholesterol-induced intimal thickening and foam cell accumulation.

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.

Infection-induced coronary dysfunction and systemic inflammation in piglets are dampened in hypercholesterolemic milieu

The synergism of infection with conventional cardiovascular risk factors in atherosclerosis is much debated. We hypothesized that coronary arterial injury correlates with infection recurrence and pathogen burden and is further aggravated by hypercholesterolemia. Forty-two Göttingen minipigs were assigned to repeated intratracheal inoculation of PBS, Chlamydia pneumoniae (Cpn), or both Cpn and influenza virus at 8, 11, and 14 wk of age. Animals were fed either standard or 2% cholesterol diet (chol-diet). At 19 wk of age coronary vasomotor responses to acetylcholine (ACh) and adenosine were assessed in vivo and blood and tissue samples were collected. Nonparametric tests were used to compare the groups. In cholesterol-fed animals, total cholesterol/HDL was significantly increased in infected animals compared with noninfected animals [3.13 (2.17–3.38) vs. 2.03 (1.53–2.41), respectively; P = 0.01]. C-reactive protein (CRP) rose in infected animals [10.60 (4.96–18.00) vs. 2.47 (1.44–3.01) μg/ml in noninfected; P < 0.01] without significant difference between the mono- and coinfected groups. Among coinfected animals, both CRP and haptoglobin were lower in those fed chol-diet than in those fed standard diet ( P < 0.05). The vasoconstricting response to ACh was most prominent in coinfected animals {769.3 (594–1,129) cm; P = 0.03 vs. noninfected [342 (309–455) cm] and P = 0.07 vs. monoinfected [415 (252.5–971.8) cm]}. Among monoinfected animals, similar to CRP, a trend for less vasoconstriction was observed in those fed chol-diet ( P = 0.08). Coinfection of piglets appears to be associated with more pronounced coronary muscarinic vasomotor dysfunction. In monoinfected animals, use of chol-diet seems to dampen both coronary dysfunction and systemic inflammation induced by infection.

Impact of seropositivity to Chlamydia pneumoniae and anti-hHSP60 on cardiovascular events in hemodialysis patients

Autoimmunity to heat shock protein 60 (HSP60) has been related to atherosclerosis. Chlamydia pneumoniae (CP), the most studied infectious agent implicated in promoting atherosclerosis, produces a form of HSP60, which can induce an autoimmune response, due to high antigenic homology with human HSP60 (hHSP60). In this study, we evaluated the correlations among anti-hHSP60 antibodies, CP infection, and cardiovascular disease (CVD) in a high-risk population, such as patients undergoing hemodialysis (HD). Thirty-two patients (67.9 ± 13.9 years; male/female, 23:9) on regular HD were enrolled. Global absolute cardiovascular risk (GCR) was assessed using the Italian CUORE Project's risk charts, which evaluate age, gender, smoking habits, diabetes, systolic blood pressure, and serum cholesterol. The occurrence of cardiovascular events during a 24-month follow-up was recorded. Seropositivity to CP and the presence of anti-hHSP60 antibodies were tested by specific enzyme-linked immunosorbent assays. Inflammation was assessed by measurement of C-reactive protein (CRP) serum levels. Fifteen healthy sex and age-matched (61.9 ± 9.5 years; male/female, 11:4) subjects were the control group. Fifteen of 32 patients resulted seropositive for CP. CP + patients were older than CP-, while they did not differ for GCR, CRP, and dialytic parameters. CVD incidence was significantly higher in CP+ (9 CP+ vs 2 CP-, p < 0.05). Cox analysis recognized that the incidence of CVD was independently correlated with seropositivity to CP (HR, 7.59; p = 0.01; 95% CI = 1.63-35.4). On the other hand, there were no significant differences in anti-hHSP60 levels among CP+, CP- and healthy subjects: 18.11 μg/mL (14.8-47.8), 31.4 μg/mL (23.2-75.3), and 24.72 μg/mL (17.7-41.1), respectively. Anti-hHSP60 did not correlate to GCR, CRP, and incidence of CVD. In conclusion, our data suggest that anti-hHSP60 autoimmune response is not related to CP infection and CP-related CVD risk in HD patients.

Infections as a stimulus for coronary occlusion, obstruction, or acute coronary syndromes

BACKGROUND

Atherosclerosis is considered to be an inflammatory disease. Infections are a significant cause of inflammation. Acute infections might precipitate acute coronary syndromes (ACS) whereas chronic infections might be stimuli for the development of atherosclerosis.

METHODS

Coronary angiograms were done on 211 of 335 patients with ACS and the percentage of coronary obstruction was determined. Serum antibody levels to Chlamydia pneumoniae, C. pneumoniae heat shock protein 60 (CpnHSP60), human heat shock protein 60 (hHSP60), enterovirus (EV), herpes simplex virus (HSV), cytomegalovirus (CMV), and two major periodontal pathogens, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, were measured in healthy controls (n = 355) and all patients.

RESULTS

Serum antibody levels to periodontal pathogens did not correlate with ACS. However, IgA-class antibody levels to Aggregatibacter actinomycetemcomitans (p = 0.021), CpnHSP60 (p = 0.048) an hHSP60 (p = 0.038) were higher in patients with coronary occlusion or obstruction compared to those without any obstruction. Odds ratios for coronary changes in the highest quartile as compared to the lower quartiles were for A. actinomycetemcomitans IgA 7.84 (95% CI 1.02-60.39, p = 0.048), for CpnHSP60 IgA 8.61 (1.12-65.89, p = 0.038), and for human HSP60 IgA 3.51 (0.79-15.69, p = 0.100).

CONCLUSIONS

We have previously reported that EV and HSV titres correlated significantly to acute coronary events. They do not correlate to the degree of coronary obstruction as shown here. However, infection by A. actinomycetemcomitans or C. pneumoniae or host response against them associated with coronary obstruction. Clinical coronary events may arise by the effect of acute infections and obstructing lesions by a chronic inflammatory stimulus.

Mannose-binding lectin as a risk factor for acute coronary syndromes

BACKGROUND

Mannose-binding lectin (MBL) is a multifunctional protein involved in innate immunity. We tested whether MBL and elevated viral and bacterial antibodies were risk factors for acute coronary events.

DESIGN

Controlled cohort study.

METHODS

A total of 354 patients with unstable angina pectoris (UA) or acute myocardial infarction (AMI) were compared with 334 paired controls.

RESULTS

Enterovirus titres were associated with increased risk of UA (odds ratio 10.04, P<0.001) and AMI (odds ratio 3.18, P=0.003), but titres did not correlate with either MBL concentration or genotype. Chlamydia pneumoniae heat shock protein 60 IgG concentrations were also associated with increased risk of UA (odds ratio 1.63, P=0.049). Compared to asymptomatic controls, patients had lower complement C3 serum concentrations (P<0.001), higher MBL serum concentration, and more frequently had MBL genotypes that determined high MBL levels (P<0.001). High MBL genotypes had odds ratios of 1.16 (P=0.010) for UA and 1.12 (P=0.007) for AMI. The elevation of MBL concentrations in the acute phase correlated with MBL concentrations after recovery (r=0.85, P<0.001).

CONCLUSIONS

Elevated microbial titres, indicating an on-going inflammation, were associated with cardiovascular events. MBL might have a dual role both decreasing susceptibility to infections and increasing the risk of acute coronary syndromes.

Serum chlamydial lipopolysaccharide as a prognostic factor for a new cardiovascular event

BACKGROUND

Infections caused by Chlamydia pneumoniae are considered to participate in inflammatory processes leading to coronary artery disease. After a primary infection, the bacteria remain dormant intracellularly causing a chronic inflammatory stimulus.

MATERIALS AND METHODS

Blood samples were obtained from 235 patients with acute myocardial infarction (AMI) and 108 patients with unstable angina pectoris (UA). We evaluated the prognostic significance of bacterial and viral antibody titers, serum troponin T, C-reactive protein, and chlamydial lipopolysaccharide (cLPS) concentrations during acute coronary syndrome of patients with AMI and UA for cardiovascular death and new UA and AMI that required hospital care during a 6-year follow-up.

RESULTS

Serum cLPS levels correlated with C-reactive protein and serum troponin T concentrations during acute coronary events. Patients with AMI had significantly higher serum concentration of cLPS compared with patients with UA. Enterovirus antibody titers and cholesterol-lowering therapy at admission of the index event were negatively correlated with cLPS concentration (r = -.198, P = .0003 and r = -.26, P = .019, respectively). The presence of circulating cLPS was associated with a hazard ratio of 2.04 for a new cardiovascular event during the follow-up period (P = .006). The area under the curve in the receiver operating graph was .572.

CONCLUSION

cLPS is evidently liberated from the infected atherosclerotic tissue during an acute coronary event. Our study supports the view that inflammation caused by C. pneumoniae infection is an important but as yet poorly understood factor in the development of atherosclerosis and may play a role in acute vascular events.

Elevated infection parameters and infection symptoms predict an acute coronary event

Background: The etiology and significance of flu-like symptoms often appearing before myocardial infarction should be clarified.

Methods: In a case-control study of 323 matched controls and a random sample of 110 out of 351 cases the presence of infection symptoms during the preceding four weeks before admission were asked and blood samples taken.

Results: Enterovirus (EV), herpes simplex virus (HSV), and Chlamydia pneumoniae IgA titers were significantly higher in cases than in controls ( p<0.001, 0.008 and 0.046, respectively). Flu-like symptoms appeared significantly more often in patients than in controls the most common one being fatigue ( p<0.001). In controls with fatigue, EV and HSV titers showed a trend to be higher (1.50 vs 1.45 and 4.29 vs 3.73) than in controls without fatigue but only HSV titers were statistically significantly higher (3.47 vs 3.96, p = 0.02). Even CRP and amyloid A concentrations (3.49 vs 2.08, p<0.0001 and 5.70 vs 3.77 mg/l, p = 0.003, respectively) as well as C4 (0.40 vs 0.44, p = 0.02) were higher in controls with fatigue.

Conclusions: Odds ratios for a coronary event in a logistic regression model were 4.79 for fatigue and 2.72 for EV antibody levels in their fourth quartile. A linear-by-linear association test showed increasing number of single symptoms with higher EV titer quartiles ( p = 0.004).

Interrelationship of interleukin 6, C-reactive protein and Chlamydia pneumoniae IgG antibodies in patients with acute coronary syndromes

BACKGROUND/AIM

Inflammation due to infection could be associated with the development of acute coronary syndromes, clinical manifestations of ongoing atherosclerosis in vessel walls. Our aim was determine whether interleukin 6, C-reactive protein and Chlamydia pneumoniae IgG antibodies are connected with the development of acute coronary syndromes, to evaluate their interrelationship and to examine whether they are predictive of new events and mortality.

METHODS

This prospective study included 211 subjects, of whom 111 were patients with acute coronary syndromes (60% male, mean age 59.42 years) and 100 were healthy controls (58% male, mean age 59.03 yuears). Blood samples were taken for analysis on admission, before the application of the therapy. Interleukin 6, high sensitivity C-reactive protein and Chlamydiapneumoniae IgG antibodies were measured, in a follow-up period of 30 days.

RESULTS

Levels of interleukin 6 (p < 0.001) and C-reactive protein (p < 0.001) were significantly higher among the patients with acute coronary syndromes than among controls. Chronic infection caused by Chlamydia pneumoniae was present in 72% of patients and in 22% of healthy controls (p < 0.001). There was a correlation between interleukin 6 and C-reactive protein, C-reactive protein and Chlamydia pneumoniae but not between Chlamydia pneumoniae and interleukin 6. Higher levels of interleukin 6 and C-reactive protein were seen with increasing body mass index, smoking exposure, presence of hypertension and diabetes, and decreasing ejection fraction. The patients with ST-segment elevation had higher examined markers than the patients without ST-segment elevation. Interleukin 6 and C-reactive protein were independently related to the clinical outcome.

CONCLUSION

Interleukin 6, C-reactive protein and Chlamydia pneumoniae infection are connected with the development of acute coronary syndromes and may reflect a clinical outcome of the disease.

Microbial risk factors of cardiovascular and cerebrovascular diseases: potential therapeutical options

Infection and inflammation may have a crucial role in the pathogenesis of atherosclerosis. This hypothesis is supported by an increasing number of reports on the interaction between chronic infection, inflammation, and atherogenesis. Assessment of serological and inflammatory markers of infection may be useful adjuncts in identifying those patients who are at a higher risk of developing vascular events, and in whom more aggressive treatments might be warranted.