Interactive role of infection, inflammation and traditional risk factors in atherosclerosis and coronary artery disease

A possible association between Chlamydiae psittacci infection and temporal arteritis

Some arguments are in favor of the role of Chlamydia in the pathogenesis of atherosclerosis and some vasculitis. Illustrating this possible relation, we report the case of a patient developing consecutively a Chlamydia psittacci infection and a temporal arteritis. A 73-year-old woman, with no significant medical history, was hospitalized for constitutional symptoms. Three weeks before, she had described fever and sore throat of two days' duration. Since that time, she had remained exhausted and developed a mild intermittent claudication of the jaws. Clinical examination was poor. A biological inflammatory syndrome was noticed. Chest X-ray revealed bilateral interstitial opacities. The titer of anti-C. psittaci antibodies was significant (positive 1g G at 1/2048). Soon after initiation of doxycycline, a temporal arteritis biopsy was performed, due to the persistence of clinical symptoms and high inflammatory syndrome, conclusive for the diagnosis of temporal arteritis. Corticotherapy was added to antibiotic therapy, resulting in the decrease of inflammatory syndrome and an improvement in the general status of the patient. X-ray opacities decreased in three weeks. Serological control after three months showed a decrease of the titer of anti-C. psittacci antibodies to 1/256, confirming the initial diagnosis of Chlamydia pneumopathy. Our observation could provide one more argument for the role of bacteria-like Chlamydia in the pathogenesis of vascular diseases. Prospective seroepidemiological and molecular biology studies could allow us to clarify the association between Chlamydia infections and inflammatory vasculitis-like temporal arteritis.

On the wide spectrum of abnormalities in the coronary arteries of Whipple's disease

BACKGROUND

There is growing interest in the role of microbes in the pathogenesis of coronary atherosclerosis but most of the evidence has been seroepidemiologic. It would be useful to know more about the cytology and histology of coronary lesions containing clearly depicted microbes.

OBJECTIVE

To define carefully the assorted abnormalities apparent in the coronary arteries of individuals dying with Whipple's disease.

METHODS

Myocardial tissue from 12 cases of Whipple's disease was studied by light microscopy. Slides were stained routinely (in sequence) with either the periodic-acid-Schiff (PAS) or Goldner-trichrome method and some with Gomori methenimine silver. Cardiac slides with PAS-positive bacilli were compared to lesions in jejunal lamina propria.

RESULTS

There were abundant sites of coronary arterial damage associated with presence of Whipple bacilli, more in the tunica media than in intima and adventitia. Bacilli in the arterial lesions were identical to those in lamina propria. Medial lesions were often associated with a fibroproliferative 'atheroma'. Both intracellular and extracellular bacilli were found. Most lesions were devoid of inflammation, but some sites exhibited either florid arteritis or dense scarring. Arteries that were scarred or inflamed exhibited only a few bacilli. There was an apparent affinity of bacilli for the nuclei in medial smooth muscle cells and in nearby ventricular myocytes. Apoptosis (TUNEL-positive) was present in medial smooth muscle cells, endothelial cells, and ventricular myocytes.

CONCLUSIONS

There is a wide spectrum of coronary abnormalities in Whipple's disease. It would be useful to know how often the Whipple bacillus is a part of the total pathogen burden in coronary disease.

Association of serum tumour necrosis factor-alpha with serum low-density lipoprotein-cholesterol and blood pressure in apparently healthy Japanese women

1. The pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha is considered to be involved in the development of atherosclerosis by inducing local inflammatory responses in the vascular wall. Because TNF-alpha is also known to affect lipid and glucose metabolism, the association between the circulating concentration of TNF-alpha and atherogenic risk factors was examined in 82 apparently healthy Japanese women (aged 19-69 years; mean age 48.5 years). 2. The mean (+/-SD) serum TNF-alpha concentration was 2.7+/-0.9 pg/mL (range 1.4-5.9 pg/mL). The TNF-alpha concentration showed significant correlations with age (r = 0.28; P = 0.01), body mass index (r = 0.27; P = 0.01), the waist-hip ratio (r = 0.41; P = 0.0002), percentage body fat (r = 0.30; P = 0.006), systolic (r = 0.32; P = 0.004) and diastolic (r = 0.24; P = 0.03) blood pressure, total cholesterol (r = 0.27; P = 0.02) and low-density lipoprotein-cholesterol (LDL-C; r = 0.36; P = 0.001), while the correlations with high-density lipoprotein-cholesterol (r = -0.20; P = 0.08) and insulin resistance estimated by the homeostasis model assessment (HOMA(IR); r = 0.16; P = 0.15) were not statistically significant. 3. When adjusted for age and menopause, TNF-alpha was significantly associated with systolic blood pressure (r = 0.25; P = 0.02) and LDL-C (r = 0.27; P = 0.02). The association between TNF-alpha and LDL-C remained significant when adjustment was made for age, menopause and the waist-hip ratio (r = 0.24; P = 0.03). 4. Our results indicate that TNF-alpha may play a role in modulating blood pressure and LDL-C.

Association of seropositivity for antibody to Chlamydia-specific lipopolysaccharide and coronary artery disease in Japanese men

Recent studies suggest an association between Chlamydia pneumoniae infection and coronary artery disease (CAD). To examine this relationship in Japanese men, serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 507 patients with CAD and 200 age-matched controls. CAD patients were divided into (1) 269 patients with myocardial infarction (MI) and (2) 238 patients with chronic coronary heart disease (CCHD). Compared with the control group, the CAD group did not differ in the prevalences of both antibodies (IgA: 23.7 vs 18.0%, p=0.10; IgG: 52.7 vs 51.0%, p=0.6). The index of IgG antibody was not significantly different between CAD and control groups (median 1.19 vs 1.18, p=0.3), whereas the index of IgA antibody was significantly higher in CAD than control group (median 0.60 vs 0.46, p<0.0001). Compared with the control group, the MI group had a significantly higher prevalence of IgA antibody (28.6 vs 18.0%, p=0.007); however, there was no difference in the prevalence of IgG antibody (58.0 vs 51.0%, p=0.13). The CCHD group did not differ in the prevalences of both antibodies (IgA: 18.1 vs 18.0%, p=0.9; IgG: 45.6 vs 51.0%, p=0.2). After the adjustment for coronary risk factors, odds ratios (ORs) of seropositive antibodies for CAD were 1.59 [95% confidence interval (CI): 0.88-2.87, p=0.12] for IgA seropositivity and 0.92 (95%CI: 0.58-1.47, p=0.7) for IgG seropositivity in all cases. In the MI and control groups, ORs of seropositive antibodies for MI were 2.67 (95%CI: 1.32-5.38, p=0.007) for IgA seropositivity, and 1.36 (95%CI: 0.79-2.36, p=0.2) for IgG seropositivity. This study discovered that IgA antibody to Chlamydia was significantly associated with CAD, especially with MI, in Japanese Men and the findings suggest that chronic infection of Chlamydia may be linked to the pathogenesis of MI.

Current infection with Helicobacter pylori, but not seropositivity to Chlamydia pneumoniae or cytomegalovirus, is associated with an atherogenic, modified lipid profile

Infectious agents may be involved in atherothrombogenesis. The potential pathogenic pathway, however, remains unclear. We investigated the association between various infectious agents and lipoproteins known to have an atherogenic effect. We recruited 470 healthy blood donors and 238 patients with angiographically proven coronary heart disease (CHD), aged 40 to 68 years. Seropositivity to Chlamydia pneumoniae (CP), chlamydial lipopolysaccharide, and cytomegalovirus (CMV) was determined; infection with Helicobacter pylori (HP) was assessed by using the [(13)C]urea breath test. In all subjects, total cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), and various apolipoproteins (apos) were determined. In unadjusted analysis, mean HDL cholesterol concentration was significantly decreased in HP-positive healthy subjects (1.36 vs 1.44 mmol/L, P=0.006) compared with HP-negative subjects. The HDL cholesterol to total cholesterol ratio was significantly decreased in HP-positive (0.259 vs 0.276, P=0.01) and CP-seropositive (0.266 vs 0.280, P=0.04) healthy subjects compared with (sero)negatives. Mean apoAI levels were significantly lower in HP-positive healthy subjects (1.46 vs 1.51 g/L, P=0.03) and in CMV-positive healthy subjects (1.47 vs 1.52 g/L, P=0.01) compared with (sero)negative subjects. After multivariable adjustment by means of linear regression analysis, only the association between HP infection and decreased HDL cholesterol (P=0.002), decreased HDL cholesterol to total cholesterol ratio (P:=0.005), decreased apoAI (P=0.02), and increased apoB (P=0.02) persisted and remained significant. There was no independent association between other lipoproteins and serological markers of CP or CMV infection. Current infection with HP, but not seropositivity to CP or CMV, was associated with an atherogenic, modified lipid profile. These lipid alterations could explain, at least in part, the reported weak association between chronic HP infection and atherosclerotic diseases.

F 12511, a novel ACAT inhibitor, and atorvastatin regulate endogenous hypercholesterolemia in a synergistic manner in New Zealand rabbits fed a casein-enriched diet

F 12511, a novel ACAT inhibitor, lowers plasma cholesterol levels in New Zealand rabbits fed a cholesterol-free casein-rich diet. In rabbits endogenous hypercholesterolemia pre-established for 8 weeks was used to compare treatments with F 12511 and atorvastatin for a further 8-week period, and to determine whether both agents act synergistically. F 12511 appears to be 3-4-fold more potent than atorvastatin in reducing total plasma cholesterol (active doses ranging from 0.16 to 2.5 and from 1.25 to 10 mg/kg per day, respectively) while the hypocholesterolemic efficacy of both compounds at 2.5 mg/kg per day amounted to 70 and 45%, respectively. A reduction by as much as 75% of esterified cholesterol in liver mediated by F 12511 could account for the decrease of plasma VLDL, LDL and apo B-100, whereas a reduction of the LDL production rate has been described as the main mechanism underlying the atorvastatin effect. F 12511 modified adrenal cholesterol balance only at the largest dose studied. In a further experiment the co-administration of threshold doses of F 12511 and atorvastatin (0.63 and 1.25 mg/kg per day, respectively) lowered plasma total cholesterol and apo B-100 containing lipoproteins to a greater extent and more rapidly than either agent alone. In the liver a decrease by atorvastatin in free cholesterol substrate for ACAT may amplify the effect of F 12511 on cholesteryl ester content leading to a diminution, in at least an additive manner, of the assembly and secretion of atherogenic lipoproteins in New Zealand rabbits which have developed an endogenous hypercholesterolemia. Thus, the combination of the ACAT inhibitor F 12511 with atorvastatin can represent a better approach than either agent alone to regulate lipoprotein metabolism in certain pathophysiological situations.

White blood cell count: an independent predictor of coronary heart disease mortality among a national cohort

An association between elevated white blood cell (WBC) count and coronary heart disease (CHD) mortality has been previously observed. However, the relationship between WBC count and CHD mortality independent of cigarette smoking and the possible interaction between WBC count and smoking remains unclear. We examined the association between WBC count and CHD mortality with Cox regression analyses of data from 8914 adults, aged 30-75, in the NHANES II Mortality Study (1976-1992). Covariates included age, sex, race, education, physical activity, smoking status, hypertensive status, total serum cholesterol, body mass index, hematocrit, and history of cardiovascular disease, stroke, and diabetes. During 17 follow-up years, there were 548 deaths from CHD (ICD-9 410-414) and 782 deaths from diseases of the heart (ICD-9 390-398, 402, 404, 410-414, 415-417, 420-429). Mean WBC count (x10(9) cells/L) was greater among persons who died from CHD (7.6 vs 7.2, P <.001). Compared to persons with a WBC count <6.1, persons with a WBC count > 7.6 were at increased risk of death from CHD (relative risk = 1.4, 95% confidence interval = 1.1-1.8) after adjustment for smoking status and other CVD risk factors. Similar results were observed among nonsmokers (RR = 1.4, 95% CI = 0.9-2.0). These results suggest that higher WBC counts are a predictor of CHD mortality independent of the effects of smoking and other traditional CVD risk factors, which may indicate a role for inflammation in the pathogenesis of CHD. Additional studies are needed to determine whether interventions to decrease inflammation can reduce the risk for CHD associated with elevated WBC.

Lack of toxic effects of F 12511, a novel potent inhibitor of acyl-coenzyme A: cholesterol O-acyltransferase, on human adrenocortical cells in culture

Inhibition of acyl-coenzyme A: cholesterol O-acyltransferase (EC 2.3.1.26; ACAT) reduces intracellular cholesteryl esters that are substrates for steroidogenesis in adrenal cells. The adrenal side effects of ACAT inhibitors remain a key point for their development as antiatherosclerotic agents. The aim of this study was to characterize the effects of a novel and powerful ACAT inhibitor, F 12511 (S)-2',3',5'-trimethyl-4'-hydroxy-alpha-dodecylthio-phenylacetanilide, on the NCI-H295R cell line, which has functional properties comparable to those of normal human adrenal cells. F 12511 incubated with cultured cells for 4-72 hr strongly inhibited cholesteryl oleate formation. The concentrations required to produce 50% inhibition (IC50) values) ranged from 20 to 50 nM; in the presence of low-density lipoproteins (LDL), this effect was paralleled by a decrease in cholesteryl ester mass and an increase in intracellular free cholesterol. At concentrations 100-fold larger than the IC(50) value for up to 48 hr, F 12511 reduced neither the basal release of cortisol and aldosterone nor the production of cortisol stimulated by forskolin. F 12511 did not modify the mRNA levels of the steroidogenic enzyme genes cytochrome P450 cholesterol side-chain cleavage (P450scc), cytochrome P450 17alpha-hydroxylase (P450c17), or cytochrome P450 21-hydroxylase (P450c21) or those of the LDL receptor and high-density lipoprotein scavenger receptor class B, type I (SR-BI) genes, either in the presence or absence of adenosine 3',5'-cyclic monophosphate stimulation for 24 hr. Exposure to F 12511 at up to 3 microM for 24 or 48 hr did not result in significant change in morphological and ultrastructural characteristics; the cytoplasm contained large numbers of mitochondria with intact crystae, and the same typical features of secretory activity were observed in NCI-H295R control cells. Exposure to 3 microM of F 12511 for 96 hr also did not affect cell viability. These data demonstrate that reduction of the substrate for steroidogenesis by the ACAT inhibitor F 12511 impairs neither steroid production nor transcription of genes involved in steroidogenesis and lipoprotein uptake in the pluripotent human adrenal cell line NCI-H295R.

Detection of Helicobacter pylori in human carotid atherosclerotic plaques

BACKGROUND AND PURPOSE

Several lines of evidence point toward a relationship between infection and atherosclerotic vascular disease. Thus, infection and inflammation often precede ischemic neurological events. Transient alterations in coagulation and direct arterial invasion by certain microorganisms have been reported. Helicobacter pylori infection is the major cause of peptic ulcer disease and appears to be a risk factor for ischemic cerebrovascular disease. However, in contrast to other chronic infectious agents, H pylori has not been consistently isolated from atherosclerotic lesions.

METHODS

We investigated the presence of H pylori in 38 atherosclerotic plaques obtained at carotid endarterectomy by using morphological and immunohistochemical techniques and a highly sensitive polymerase chain reaction method. We performed immunohistochemical detection of intercellular adhesion molecule-1, a marker related to inflammatory cell response. We also examined 7 carotid arteries obtained at autopsy from subjects without carotid atherosclerosis.

RESULTS

H pylori DNA was found in 20 of 38 atherosclerotic plaques. Ten of the H pylori DNA-positive plaques also showed morphological and immunohistochemical evidence of H pylori infection. None of 7 normal carotid arteries was positive for H pylori. Intercellular adhesion molecule-1 was expressed in 75% of H pylori-positive plaques and in 22% of H pylori-negative plaques. The presence of the microorganism was associated with male sex but was independent of age, vascular risk factor profile, and prior neurological symptoms.

CONCLUSIONS

H pylori is present in a substantial number of carotid atherosclerotic lesions and is associated with features of inflammatory cell response. This study provides additional evidence of the relationship between H pylori infection and atherosclerotic disease.

C-reactive protein, fibrinogen, interleukin-6 and tumour necrosis factor-alpha in the prognostic classification of unstable angina pectoris

BACKGROUND

Inflammatory process has been found to play an important role in the pathogenesis of coronary heart disease (CHD) and in the prognosis of CHD patients. AIM. The aim of this study was to investigate the prognostic value of C-reactive protein (CRP), fibrinogen, interleukin (IL)-6 and tumour necrosis factor-alpha (TNF-alpha) in patients with unstable angina pectoris (UAP), including factor analysis to assess their joint effects.

METHODS

The study comprised 263 consecutive patients (159 men, 104 women; median age 68 years) with UAP. Blood samples for the acute-phase protein and cytokine determinations were drawn on admission.

RESULTS

Coronary mortality during the median follow-up time of 17 months was 6-fold higher in the highest tertile for CRP and IL-6 and 3.5-fold higher in the highest tertile for fibrinogen and TNF-alpha than in the respective combined lower tertiles. Factor analysis produced two underlying factors, ie the 'inflammation' factor, including CRP, fibrinogen and IL-6, and the 'injury' factor, including troponin T, creatine kinase MB mass and TNF-alpha. In Cox models, both of these factors were independent predictors of the risk of coronary death and major coronary events (coronary death or nonfatal myocardial infarction).

CONCLUSIONS

Elevated levels of acute-phase proteins and cytokines, particularly CRP and IL-6, are strong predictors of the risk of serious coronary events in patients with UAP.

Is the observed association between periodontitis and atherosclerosis causal?

Most of the documentation of possible causal links between periodontitis and atherosclerosis-related diseases appears indirect or circumstantial. There is, however, an increasing number of both experimental and longitudinal epidemiological studies which seem to support a causal relationship. A critical evaluation of the epidemiological data available might therefore be appropriate. The present study is based on a literature search using Ovid medical data base covering the period from 1989 to October 2000 and applying specific inclusion criteria. Based on a critical evaluation of the 14 investigations selected from a total of 21 retrieved from the search, a causal relationship between periodontitis and atherosclerosis-related diseases appeared possible. However, the nature both of periodontitis and atherosclerosis is multifactorial, and caution should be exercised when implicating periodontal disease in the causation of atherosclerotic disorders.

Instability of coronary lesions in unstable angina assessed by C-reactive protein values following coronary interventions

The instability of coronary lesions was evaluated in 30 patients with stable angina and 60 patients with unstable angina. The grade of instability of coronary lesions as predicted by the increases in C-reactive protein induced by PTCA and/or stenting was closely correlated with Braunwald's classification of unstable angina.

Effects of seasonal mood changes on seasonal variations in coronary heart disease: role of immune system, infection, and inflammation

Coronary heart disease shows a winter peak and summer trough in incidence and mortality. A substantial part of a general population experiences seasonal mood changes including winter depression. Many studies demonstrate that depression is associated with increased incidence, morbidity, and mortality of cardiovascular disease. Therefore, the author previously suggested that persons with high levels of seasonality may be at increased risk of developing or worsening of coronary heart disease in the winter. Some psychological factors promote the development of disorders of the cardiovascular system. The same psychological factors decrease immunity and promote infection. There is evidence that the infectious process is involved in the pathogenesis of coronary heart disease. Therefore, the author previously proposed that the development of infection and inflammation in the atherosclerotic plaque may be related to the psychological disorders that suppress the immune system. In this paper, the author suggests that winter depression-induced suppression of the immune system may contribute to the winter increase in incidence and mortality of cardiovascular disease.

Ongoing viral replication is required for gammaherpesvirus 68-induced vascular damage

The role of autoimmunity in large-vessel vasculitis in humans remains unclear. We have previously shown that infection of gamma interferon receptor knockout (IFN-gamma R(-/-)) mice with gammaherpesvirus 68 (gamma HV68) results in severe inflammation of the large elastic arteries that is pathologically similar to the lesions observed in Takayasu's arteritis, the nongranulomatous variant of temporal arteritis, and Kawasaki's disease (K. E. Weck et al., Nat. Med. 3:1346-1353, 1997). Here we define the mechanism of damage to the elastic arteries. We show that there is a persistent productive infection of the media of the large elastic vessels. In addition, we demonstrate that persistent virus replication is necessary for chronic arteritis, since antiviral therapy of mice with established disease resulted in increased survival, clearance of viral antigen from the media of the affected vessel, and dramatic amelioration of arteritic lesions. These data argue that ongoing virus replication, rather than autoimmunity, is the cause of gamma HV68-induced elastic arteritis.

Activated coagulation/fibrinolysis system and platelet function in acute thrombotic stroke patients with increased C-reactive protein levels

The relationship between systemic infection or inflammation and an increased risk of thrombotic diseases has recently raised renewed interest. In order to determine the mechanisms underlying this relationship, we determined plasma levels of coagulation/fibrinolysis markers and platelet function in patients with acute thrombotic stroke (<24 h after onset) prior to treatment, and compared the results between cases with elevated and normal C-reactive protein (CRP) levels and controls. Plasma levels of thrombin-antithrombin complex (TAT), plasmin-antiplasmin complex, and D-dimer were significantly higher in patients with elevated CRP levels than in those with normal CRP levels and controls (P<0.005). Platelet aggregation induced by 1 and 10 microM ADP was significantly higher in patients with elevated CRP levels than those with normal CRP levels (P<0.05). These findings suggest that activation of the coagulation/fibrinolysis system and platelet function may be in part related to stroke onset in patients with increased CRP levels.

Identification of periodontal pathogens in atheromatous plaques

BACKGROUND

Recent studies suggest that chronic infections including those associated with periodontitis increase the risk for coronary vascular disease (CVD) and stroke. We hypothesize that oral microorganisms including periodontal bacterial pathogens enter the blood stream during transient bacteremias where they may play a role in the development and progression of atherosclerosis leading to CVD.

METHODS

To test this hypothesis, 50 human specimens obtained during carotid endarterectomy were examined for the presence of Chlamydia pneumoniae, human cytomegalovirus, and bacterial 16S ribosomal RNA using specific oligonucleotide primers in polymerase chain reaction (PCR) assays. Approximately 100 ng of chromosomal DNA was extracted from each specimen and then amplified using standard conditions (30 cycles of 30 seconds at 95 degrees C, 30 seconds at 55 degrees C, and 30 seconds at 72 degrees C). Bacterial 16S rDNA was amplified using 2 synthetic oligonucleotide primers specific for eubacteria. The PCR product generated with the eubacterial primers was transferred to a charged nylon membrane and probed with digoxigenin-labeled synthetic oligonucleotides specific for Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, and Prevotella intermedia.

RESULTS

Eighty percent of the 50 endarterectomy specimens were positive in 1 or more of the PCR assays. Thirty-eight percent were positive for HCMV and 18% percent were positive for C. pneumoniae. PCR assays for bacterial 16S rDNA also indicated the presence of bacteria in 72% of the surgical specimens. Subsequent hybridization of the bacterial 16S rDNA positive specimens with species-specific oligonucleotide probes revealed that 44% of the 50 atheromas were positive for at least one of the target periodontal pathogens. Thirty percent of the surgical specimens were positive for B. forsythus, 26% were positive for P. gingivalis, 18% were positive for A. actinomycetemcomitans, and 14% were positive for P. intermedia. In the surgical specimens positive for periodontal pathogens, more than 1 species was most often detected. Thirteen (59%) of the 22 periodontal pathogen-positive surgical specimens were positive for 2 or more of the target species.

CONCLUSIONS

Periodontal pathogens are present in atherosclerotic plaques where, like other infectious microorganisms such as C. pneumoniae, they may play a role in the development and progression of atherosclerosis leading to coronary vascular disease and other clinical sequelae.

Inflammation and infection in acute coronary syndrome

Basic science research has revealed that monocytes and macrophages are important factors in atherogenesis. Immune system activation occurs at all stages of plaque formation, from the fatty streak to an advanced, complicated lesion. The inflammatory response not only stimulates changes in coronary artery endothelial cells causing endothelial injury and dysfunction, but also plays a role in plaque instability and rupture. New perspectives of atherosclerosis and acute coronary syndromes will be discussed in relation to inflammation. In addition, discussion will focus on bacterial and viral infectious microorganisms as a potential factor that may induce and promote inflammation and lead to acute coronary events. Clinical studies in humans have provided insight relating inflammation and infectious agents to atherosclerosis and plaque vulnerability. Other studies focus on specific interventions that may aid in diagnosis and treatment.

Common polymorphism in the promoter of the CD14 monocyte receptor gene is associated with acute myocardial infarction in Japanese men

We investigated whether C(-260)-->T polymorphism in the promoter of the CD14 monocyte receptor gene predisposed to coronary atherosclerosis and acute myocardial infarction (AMI) in Japanese men. The frequencies of T allele and T/T homozygotes in patients with AMI were significantly higher than in controls and in patients with angina without prior AMI, suggesting that the CD14 promoter polymorphism is associated with AMI rather than with coronary atherosclerosis, and this polymorphism may be one of the genetic risk factors for AMI in Japanese men.

Endothelial dysfunction after repeated Chlamydia pneumoniae infection in apolipoprotein E-knockout mice

BACKGROUND

Arterial relaxation is largely regulated by endothelial nitric oxide (NO). Its diminished activity has been associated with incipient atherosclerosis. We investigated the endothelium-dependent relaxation of aorta in apolipoprotein E-knockout (apoE-KO) mice exposed to single or repeated Chlamydia pneumoniae inoculation.

METHODS AND RESULTS

Forty-eight apoE-KO mice, 8 weeks old, were inoculated intranasally with C pneumoniae (n=24) or saline (n=24) every 2 weeks over a 6-week period. Twenty mice (10 infected and 10 controls) were killed at 2 weeks and 6 weeks, respectively, after the first inoculation. The smooth muscle tone of aortic rings was measured in vitro at both time points. The norepinephrine-precontracted thoracic aortic rings were successively exposed to methacholine in the absence and presence of N:(G)-nitro-L-arginine methyl ester (L-NAME) and diclofenac. The methacholine-induced relaxation was attenuated in the infected mice at 6 weeks in both the absence and presence of L-NAME (P:<0.05 and P:<0.01, respectively). When administered together with L-NAME, diclofenac enhanced the relaxation of the L-NAME-pretreated aortas in infected mice at 2 weeks (P:<0.05) but not in noninfected mice. The relaxation response from infected mice tended to differ in the same manner at 6 weeks (P:<0.1). No intimal thickening was detected at either time point.

CONCLUSIONS

C pneumoniae impairs arterial endothelial function, and the NO pathway is principally involved. Cyclooxygenase-dependent vasoconstricting products may also account for the infection-induced impaired relaxation. These findings further support the role of C pneumoniae infection in atherosclerosis development.

Prognostic value of C-reactive protein levels within six hours after the onset of acute myocardial infarction

BACKGROUND

Inflammation is an important feature of atherosclerotic lesions, and the vulnerability of coronary lesions in acute myocardial infarction (AMI) at the time of onset may be related to blood levels of C-reactive protein (CRP) on admission, before CRP levels are affected by myocardial damage.

METHODS

A total of 234 patients with AMI in whom plasma CRP was measured within 6 hours after onset were studied. They were divided into 2 groups: group 1 (n = 49) with elevated CRP (>/=0.3 mg/dL) on admission within 6 hours after onset and group 2 (n = 185) with normal CRP (<0.3 mg/dL) within 6 hours after onset. All were treated by primary percutaneous transluminal coronary angioplasty with provisional stenting.

RESULTS

There were no significant differences in baseline characteristics between the 2 groups. In-hospital adverse coronary events, including coronary reocclusion, reinfarction, target vessel revascularization, and death, were significantly more frequent in group 1 (22.4%) than in group 2 (4.3%, P <.005), and bailout stenting was performed significantly more frequently in group 1 (61. 2%) than in group 2 (37.8%, P <.005). In contrast, there were no significant differences between the 2 groups in parameters that represent myocardial damage, including peak creatine kinase and left ventricular ejection fraction.

CONCLUSION

CRP levels within 6 hours after the onset of AMI reflect the vulnerability of culprit coronary lesions and predict adverse coronary events after primary PTCA/stenting.

Gene expression of inflammatory mediators in different chambers of the human heart

BACKGROUND

Inflammatory genes may be unevenly expressed in different heart chambers.

METHODS

Biopsies were taken simultaneously from the right atrium (RA), left atrium (LA), and left ventricle (LV) of 19 patients before cardioplegic arrest during open heart surgery. The mRNA expression of tumor necrosis factor alpha (TNFalpha), interleukin 1beta (IL-1beta), inducible and endothelial nitric oxide synthase (iNOS and eNOS), endothelin-1 (ET-1), E-selectin (CD62E), intercellular adhesion molecule-1 (ICAM-1) and its ligand CD18, and CD25 was evaluated with semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Expression of TNFalpha mRNA was higher in RA than LA and LV (p<0.05), whereas IL-1beta was more expressed in LA than RA (p<0.05), which was higher than LV (p<0.0001). There were no significant regional differences in the expression of ICAM-1, CD62E, CD25, iNOS, and eNOS. CD18 was higher in RA than LA (p<0.05); ET-1 was more expressed in RA than LV (p<0.04). Patients with stable angina had no expression of eNOS.

CONCLUSIONS

Gene expression of inflammatory mediators was detected in the hearts of patients with different cardiovascular disorders, and was unevenly distributed in different heart chambers. Cardiac biopsies should be taken from the same site.

Current, new and future treatments in dyslipidaemia and atherosclerosis

The new therapeutic options available to clinicians treating dyslipidaemia in the last decade have enabled effective treatment for many patients. The development of the HMG-CoA reductase inhibitors (statins) have been a major advance in that they possess multiple pharmacological effects (pleiotropic effects) resulting in potent reductions of low density lipoproteins (LDL) and prevention of the atherosclerotic process. More recently, the newer fibric acid derivatives have also reduced LDL to levels comparable to those achieved with statins, have reduced triglycerides, and gemfibrozil has been shown to increase high density lipoprotein (HDL) levels. Nicotinic acid has been made tolerable with sustained-release formulations, and is still considered an excellent choice in elevating HDL cholesterol and is potentially effective in reducing lipoprotein(a) [Lp(a)] levels, an emerging risk factor for coronary heart disease (CHD). Furthermore, recent studies have reported positive lipid-lowering effects from estrogen and/or progestogen in postmenopausal women but there are still conflicting reports on the use of these agents in dyslipidaemia and in females at risk for CHD. In addition to lowering lipid levels, these antihyperlipidaemic agents may have directly or indirectly targeted thrombogenic, fibrinolytic and atherosclerotic processes which may have been unaccounted for in their overall success in clinical trials. Although LDL cholesterol is still the major target for therapy, it is likely that over the next several years other lipid/lipoprotein and nonlipid parameters will become more generally accepted targets for specific therapeutic interventions. Some important emerging lipid/lipoprotein parameters that have been associated with CHD include elevated triglyceride, oxidised LDL cholesterol and Lp(a) levels, and low HDL levels. The nonlipid parameters include elevated homocysteine and fibrinogen, and decreased endothelial-derived nitric oxide production. Among the new investigational agents are inhibitors of squalene synthetase, acylCoA: cholesterol acyltransferase, cholesteryl ester transfer protein, monocyte-macrophages and LDL cholesterol oxidation. Future applications may include thyromimetic therapy, cholesterol vaccination, somatic gene therapy, and recombinant proteins, in particular, apolipoproteins A-I and E. Non-LDL-related targets such as peroxisome proliferator-activating receptors, matrix metalloproteinases and scavenger receptor class B type I may also have clinical significance in the treatment of atherosclerosis in the near future. Before lipid-lowering therapy, dietary and lifestyle modification is and should be the first therapeutic intervention in the management of dyslipidaemia. Although current recommendations from the US and Europe are slightly different, adherence to these recommendations is essential to lower the risk of atherosclerotic vascular disease, more specifically CHD. New guidelines that are expected in the near future will encompass global opinions from the expert scientific community addressing the issue of target LDL goal (aggressive versus moderate lowering) and the application of therapy for newer emerging CHD risk factors.

Detection of Chlamydia pneumoniae in giant cell vasculitis and correlation with the topographic arrangement of tissue-infiltrating dendritic cells

OBJECTIVE

Recent studies suggest that giant cell arteritis (GCA) may be an antigen-driven disease. Since Chlamydia pneumoniae has been identified in arterial vessel walls, it was hypothesized that this organism might be associated with GCA.

METHODS

Fourteen paraffin-embedded temporal artery biopsy specimens from 9 patients with GCA were examined by immunohistochemistry and by polymerase chain reaction (PCR) for the presence of C pneumoniae; for 5 patients, specimens were available from both the left and right arteries. Four temporal artery specimens from 3 patients with polymyalgia rheumatica (PMR) and 9 temporal artery specimens from 5 patients without GCA or PMR served as controls.

RESULTS

C pneumoniae was detected by both immunohistochemistry and PCR in 6 GCA patient samples. One GCA patient sample was immunopositive only; another was PCR positive only. Thus, C pneumoniae was found in 8 of 9 GCA patients. One of 4 control samples from the PMR patients was immunopositive, but PCR negative, for C pneumoniae. The C pneumoniae-positive PMR patient also had respiratory symptoms. The remaining 9 control samples were negative for C pneumoniae by both immunohistochemistry and PCR. Immunohistochemistry showed that bacteria predominate in the adventitial layer of temporal arteries, in granulomatous infiltrates. Dendritic cells were examined by immunohistochemistry for their presence and localization in consecutive temporal artery specimens, and showed a strong topographic relationship with C pneumoniae. Like the bacterium, dendritic cells predominate in the adventitial layer of the arteries.

CONCLUSION

C pneumoniae was found in temporal artery specimens from most GCA patients, in 1 specimen from a PMR patient, and in no other control specimens; thus, it may play a role in the pathogenesis of the disease. Dendritic cells may represent the antigen-presenting cells in this situation.

Phosphatidylserine-dependent adhesion of T cells to endothelial cells

Phosphatidylserine (PS) was exposed at the surface of human umbilical vein endothelial cells (HUVECs) and cultured cell lines by agonists that increase cytosolic Ca(2+), and factors governing the adhesion of T cells to the treated cells were investigated. Thrombin, ionophore A23187 and the Ca(2+)-ATPase inhibitor 2, 5-di-tert-butyl-1,4-benzohydroquinone each induced a PS-dependent adhesion of Jurkat T cells. A23187, which was the most effective agonist in releasing PS-bearing microvesicles, was the least effective in inducing the PS-dependent adhesion of Jurkat cells. Treatment of ECV304 and EA.hy926 cells with EGTA, followed by a return to normal medium, resulted in an influx of Ca(2+) and an increase in adhering Jurkat cells. Oxidised low-density lipoprotein induced a procoagulant response in cultured ECV304 cells and increased the number of adhering Jurkat cells, but adhesion was not inhibited by pretreating ECV304 cells with annexin V. PS was not significantly exposed on untreated Jurkat cells, as determined by flow cytometry with annexin V-FITC. However, after adhesion to thrombin-treated ECV304 cells for 10 min followed by detachment in 1 mM EDTA, there was a marked exposure of PS on the Jurkat cells. Binding of annexin V-FITC to the detached cells was inhibited by pretreating them with unlabelled annexin V. Contact with thrombin-treated ECV304 cells thus induced the exposure of PS on Jurkat cells and, as Jurkat cells were unable to adhere to thrombin-treated ECV304 cells in the presence of EGTA, the adhesion of the two cell types may involve a Ca(2+) bridge between PS on both cell surfaces. The number of T cells from normal, human peripheral blood that adhered to ECV304 cells was not increased by treating the latter with thrombin. However, findings made with several T cell lines were generally, but not completely, consistent with the possibility that adhesion to surface PS on endothelial cells may be a feature of T cells that express both CD4(+) and CD8(+) antigens. Possible implications for PS-dependent adhesion of T cells to endothelial cells in metastasis, and early in atherogenesis, are discussed.

Relationship of Chlamydia pneumoniae infection to severity of human coronary atherosclerosis

BACKGROUND

Infection with Chlamydia pneumoniae has been postulated to play a pathogenic role in atherosclerosis. We examined the role of infection with C pneumoniae in relation to the extent of coronary atherosclerosis.

METHODS AND RESULTS

Coronary atherosclerosis was graded microscopically on a postmortem basis in a blinded fashion in 60 subjects as mild (n=18) or severe (n=42) atherosclerosis. Serum antibodies to C pneumoniae were measured by microimmunofluorescence test. Paraffin-embedded coronary artery specimens were examined for the presence of chlamydia by use of a genus-specific direct immunofluorescence monoclonal antibody. Frozen coronary artery specimens were examined by immunoperoxidase for the presence of C pneumoniae by use of a specific monoclonal antibody RR-402. Direct immunofluorescence was reactive in 86% of cases with severe atherosclerosis but in only 6% of cases with mild atherosclerosis (P<0.01), whereas immunoperoxidase staining was reactive in 80% and 38% of cases with severe and mild atherosclerosis, respectively (P<0. 01). Elevated IgG and IgA levels against C pneumoniae were not different in cases with severe and mild atherosclerosis (61% and 30% for severe atherosclerosis and 67% and 42% for mild atherosclerosis, respectively).

CONCLUSIONS

This study supports the hypothesis that intracellular infection with C pneumoniae may relate to the severity of atherosclerosis in some subjects. Serum antibody titers against C pneumoniae do not differentiate between severe and mild atherosclerosis.

Seropositivity against Chlamydia pneumoniae in patients with coronary atherosclerosis

BACKGROUND

Results of therapy in patients with unstable coronary syndromes with antibiotics directed against Chlamydia pneumoniae have been variable, perhaps due to the heterogeneity of patients in these trials.

HYPOTHESIS

The aim of the present study was to correlate the severity of coronary artery disease (CAD) with seropositivity against C. pneumoniae prospectively.

METHODS

We measured the frequency of seropositivity (IgG levels > or = 1/64 and IgA levels > or = 1/16 against Chlamydia pneumoniae) in 110 patients with CAD and in 49 controls.

RESULTS

As expected, traditional CAD risk factors were seen more often in patients with CAD than in controls. Mean values of total cholesterol (184 +/- 52 and 166 +/- 44 mg/dl, respectively) and triglyceride (143 +/- 60 and 112 +/- 63 mg/dl, respectively) in serum were significantly higher in patients with CAD than in controls (both p < 0.04). There were no significant differences between the two groups in serum high-density lipoprotein cholesterol (34 +/- 13 and 32 +/- 14 mg/dl, respectively) and lipoprotein (a) (Lp(a):241 +/- 247 and 223 +/- 263 mg/l, respectively) levels. The rate of IgG seropositivity was 52% (28/54) in patients with stable CAD, 41% (23/56) in patients with unstable CAD, and 35% in controls (p = NS). The rate of IgA seropositivity was 25% (14/54) in patients with stable CAD, 12% (6/49) in patients with unstable angina, and 12% (6/49) in controls (all p = NS).

CONCLUSIONS

Only a small percentage of patients with CAD demonstrate seropositivity against Chlamydia pneumoniae. Antibiotic therapy in these selected patients, but not in the remaining patients, may be considered rational. These considerations may underlie the failure to see consistent benefits of antibiotic therapy in patients with CAD.

Chlamydia pneumoniae and atherosclerosis

Chlamydia pneumoniae (C. pneumoniae) is a common respiratory pathogen. Many reports have documented the presence of C. pneumoniae in atheromatous coronary arteries, aorta, carotid arteries, and peripheral arteries using a variety of techniques. There is clear experimental evidence that C. pneumoniae can infect macrophages, endothelial cells, smooth muscle cells, and induce the formation of foam cells. Evidence from basic research and epidemiologic studies suggest that C. pneumoniae can induce macrophage foam cell formation by dysregulating native LDL uptake or metabolism (or both). Relatively small, secondary prevention studies, have suggested that antibiotic therapy might reduce monocyte activation and C. pneumoniae antibody titers, reduce inflammatory markers and possibly reduce adverse cardiovascular events. It is possible that C. pneumoniae enhances atherogenesis by causing inflammation and eliciting immune responses and may be one of the factors contributing to this multifactorial disease process.

Human ApoA-IV overexpression in transgenic mice induces cAMP-stimulated cholesterol efflux from J774 macrophages to whole serum

The role of apolipoprotein A-IV (apoA-IV) in lipoprotein metabolism has not been established. The aim of the present study was to investigate the role of apoA-IV in reverse cholesterol transport by comparing cellular cholesterol efflux to serum or serum fractions from control mice and from mice transgenic for human apoA-IV (HuA-IVTg mice). When Fu5AH hepatoma cells were used, the cholesterol efflux to serum from either control or transgenic mice was similar. When control J774 macrophage cells were used, a comparison of efflux to serum or lipoprotein-deficient serum (LPDS) failed to demonstrate any differences between control and transgenic mice. In contrast, when the J774 cells were pretreated with cAMP, there was a stimulation of efflux to whole serum or LPDS from HuA-IVTg mice. cAMP treatment had no effect on efflux to serum or LPDS from control mice. Pretreatment of the cells with cAMP did not enhance the efflux response to high density lipoprotein isolated from HuA-IVTg mouse serum. Our results suggest that apoA-IV, unassociated with high density lipoprotein particles, is responsible for enhanced cholesterol efflux. This study illustrates the role of lipid-free apolipoproteins in mediating cellular cholesterol efflux with use of a biological fluid and is potentially of physiological relevance, especially in apolipoprotein-rich extravascular fluids.

Infectious agents are not necessary for murine atherogenesis

Recent work has revealed correlations between bacterial or viral infections and atherosclerotic disease. One particular bacterium, Chlamydia pneumoniae, has been observed at high frequency in human atherosclerotic lesions, prompting the hypothesis that infectious agents may be necessary for the initiation or progression of atherosclerosis. To determine if responses to gram-negative bacteria are necessary for atherogenesis, we first bred atherosclerosis-prone apolipoprotein (apo) E(-/)- (deficient) mice with animals incapable of responding to bacterial lipopolysaccharide. Atherogenesis was unaffected in doubly deficient animals. We further tested the role of infectious agents by creating a colony of germ-free apo E(-/)- mice. These animals are free of all microbial agents (bacterial, viral, and fungal). Atherosclerosis in germ-free animals was not measurably different from that in animals raised with ambient levels of microbial challenge. These studies show that infection is not necessary for murine atherosclerosis and that, unlike peptic ulcer, Koch's postulates cannot be fulfilled for any infectious agent in atherosclerosis.

Increased serum neopterin: a marker of coronary artery disease activity in women

OBJECTIVE

To assess whether neopterin concentrations in women with unstable angina differ from those in women with chronic stable angina.

DESIGN

Prospective cohort study.

SETTING

University hospital in south west London.

PATIENTS

114 consecutive women with angina were studied: 82 had chronic stable angina (typical exertional chest pain, positive exercise ECG testing, and/or abnormal myocardial scintigraphy; symptoms stable for at least three months), and 32 had unstable angina (Braunwald class III). All patients with chronic stable angina (100%) and 18 with unstable angina (56.3%) underwent digital coronary angiography; neopterin concentrations were determined using a commercially available immunoassay.

MAIN OUTCOME MEASURES

Major clinical events during one year follow up were readmission with Braunwald's class IIIb unstable angina, non-fatal myocardial infarction, and cardiac death.

RESULTS

Major events occurred in 12 women with chronic stable angina (14.6%) and nine women with unstable angina (28.1%). Mean (range) neopterin concentrations were significantly higher in women with unstable angina than in those with chronic stable angina (7.6 (5.1-11.5) nmol/l v 5.9 (4.4-7.5) nmol/l; p = 0.003), even after adjustment for variables which were significantly different on univariate analysis. In women with chronic stable angina, baseline neopterin concentrations were higher in those with cardiac events than in those without events (7.1 (5.9-9.1) nmol/l v 5.7 (3.9-7.3 nmol/l); p = 0.010), even after adjustment for variables with significant differences between both groups on univariate analysis.

CONCLUSIONS

On average, women with unstable angina had significantly higher neopterin concentrations than women with chronic stable angina. Women with chronic stable angina with events during follow up had higher neopterin concentrations than those without events. Neopterin concentrations were similar in patients with unstable angina and women with chronic stable angina who developed events. Neopterin concentrations may therefore be a marker of risk in women with coronary artery disease.

Immunomodulation of atherosclerosis: myth and reality

Atherosclerosis is an inflammatory disease which displays features of immune activation both locally and systemically. In the present review, we discuss the evidence for immune activation in human disease and experimental models, and survey candidate antigens associated with atherosclerosis. Studies of atherosclerosis in genetic models of immunodeficiency are analysed, as well as immunomodulating therapies and immunization protocols. Based on recent research, it is concluded that immunomodulation represents an interesting approach to the development of new prevention and treatment methods for atherosclerosis.

Markers of inflammation as predictors in cardiovascular disease

Recent research suggests that inflammation in the coronary arteries may be intimately involved in the development of atherosclerosis and its associated acute coronary syndromes. Experimental and clinical studies based on the biochemical markers of inflammation and vascular perturbation in plasma as well as in atherosclerotic tissue have provided substantial evidence of ongoing inflammation in coronary heart disease. These studies have suggested a potential role for biochemical markers of inflammation in the prediction of risk for the development of coronary heart disease as well as in the prediction of adverse cardiac-related outcomes in patients with known coronary syndromes. Markers of inflammation appear to offer risk prediction information that is independent of, and possibly complementary to, traditional risk factors for the development of cardiovascular disease. There are numerous potential markers for these inflammatory processes and their interdependence remains somewhat unclear. Clinical studies have investigated some, but not all of these markers in a critical and comparative fashion. Therefore, further well-designed prospective studies should elucidate the role of markers of inflammation in the prediction, diagnosis, and management of cardiovascular disease.

Inflammation, infection and atherosclerosis: do antibacterials have a role in the therapy of coronary artery disease?

Since the recent publication of 3 studies on the use of antibacterials in patients with coronary artery disease (CAD), there has been a phenomenal interest in the role of infection in the genesis of CAD. It is now generally accepted that inflammation accompanies atherosclerosis from its initiation to the evolution of end-events. Inflammation may occur in response to traditional risk factors, such as hyperlipidaemia, smoking and diabetes mellitus. There is a recent resurgence of the concept that inflammation may have an infectious basis. This concept is based on the identification of microorganisms in the atherosclerotic plaque and seropositivity. The data on eradication of the offending organism with antibiotics and prevention of atherosclerosis-related events have, however, been inconsistent. This may reflect lack of precise understanding of steps leading to atherosclerosis and the evolution of acute ischaemic events. Further work in this area may help identify subsets of patient populations within which infection may play a causative role in the genesis of CAD. Targeted therapy then may be considered logical.

Prospective crossover trial of the influence of vitamin E-coated dialyzer membranes on T-cell activation and cytokine induction

Cytokine induction by dialyzer membranes has been related to several acute and chronic side effects of hemodialysis treatment, among them being immune dysfunction and progressive atherosclerosis. Surface modification of cuprophane dialyzers with the antioxidant vitamin E is a new approach to enhance biocompatibility and improve cytokine levels, as well as immune function. Twenty-one patients undergoing treatment with hemophane (HE) dialyzers were enrolled onto a crossover study with a vitamin E-coated (VE) dialyzer or a synthetic polyamide (PA) dialyzer. In vitro assays of lymphocyte activation and measurements of cytokine induction were performed to evaluate biocompatibility. Four weeks of treatment with either VE or PA dialyzers enhanced in vitro proliferation of peripheral blood leukocytes in comparison to treatment with HE membranes used before study entry. Enhancement of lymphocyte function was independent of dialysis efficiency, which was kept constant during the study. In the interdialytic interval, preactivation of monocytes for the production of interleukin-6 (IL-6) did not differ between VE or PA dialysis. In contrast, the VE membrane reduced acute production of IL-6 during a dialysis treatment, whereas the PA membrane did not. Unlike IL-6, the regulatory cytokine IL-10 is not inhibited by either membrane. This is important because IL-10 is believed to have a beneficial effect on immune function in dialysis patients. The VE membrane, despite being based on a cuprophane backbone, is similar to the highly biocompatible PA dialyzer in terms of its effect on lymphocyte function, whereas it exerts an additional suppressive effect on the overproduction of proinflammatory cytokines.

Seropositivity to chlamydial lipopolysaccharide and Chlamydia pneumoniae, systemic inflammation and stable coronary artery disease: negative results of a case-control study

OBJECTIVES

We investigated the association between seropositivity to chlamydial lipopolysaccharide (cLPS) or Chlamydia pneumoniae (CP) and angiographically documented coronary artery disease (CAD), and we examined the relationship between serostatus and markers of systemic inflammation.

BACKGROUND

The potential contribution of CP to atherogenesis is still a matter of debate, and inflammation has been suggested to represent the link between infection and atherosclerotic disease.

METHODS

Subjects age 40 to 68 years were recruited for this case-control study between October 1996 and November 1997: 312 patients with at least one coronary stenosis >50% and 479 age- and sex-matched blood donors without manifest CAD or history of angina. Antibodies against cLPS and CP, C-reactive protein (CRP), fibrinogen, plasma viscosity, leukocytes and neutrophils were determined. The study had a power of >80% to detect an odds ratio (OR) of 1.55 or above for the prevalence of immunoglobulin (IgG) antibodies against cLPS at a significance level of alpha = 0.05.

RESULTS

Prevalence of IgG antibodies against cLPS was not different between cases and controls (61% vs. 62%; p = 0.7). The adjusted OR for the presence of CAD given positive IgG serostatus against cLPS was 0.9 (95% CI; 0.6 to 1.3). Similarly, no difference in the prevalence of IgG antibodies against CP was seen (88% vs. 87%; p = 0.6); the adjusted OR was 1.0 (95% CI; 0.6 to 1.6). Markers of inflammation did not show any statistically significant difference between cLPS seropositives and seronegatives.

CONCLUSIONS

Our results indicate no strong association between CP and CAD, and increased systemic inflammation in patients with CAD does not seem to be due to seropositivity to cLPS or CP.

Infection with Helicobacter pylori is not a major independent risk factor for stable coronary heart disease: lack of a role of cytotoxin-associated protein A-positive strains and absence of a systemic inflammatory response

BACKGROUND

There is controversy about the association between Helicobacter pylori infection and manifestations of coronary heart disease (CHD), the potential role of the more virulent H pylori strains, and whether or not a positive serostatus is related to increased levels of markers of systemic inflammation.

METHODS AND RESULTS

We assessed the prevalence of an infection with H pylori and in particular the anti-cytotoxin-associated protein A (CagA) antibody response of the more virulent strains expressing CagA in 312 patients with stable CHD and in 479 control subjects. Serological prevalence of H pylori infection (IgG titer) was significantly higher in patients than in control subjects after adjustment for age and sex (44.2% versus 31.3%, P<0.001). After adjustment for various covariates in multiple logistic regression, the odds ratio (OR) for CHD was 1.3 (95% CI, 0.9 to 1.9) given a positive IgG serostatus. The prevalence of CagA-positive strains was 27.9% in patients and 21.7% in control subjects (P=0.076 adjusted for age and sex). The OR for CHD in the fully adjusted model was 1.1 (95% CI, 0.7 to 1.7). None of the inflammatory markers (C-reactive protein, fibrinogen, plasma viscosity, or leukocytes) was significantly different according to serostatus.

CONCLUSIONS

In this large case-control study, the association of H pylori infection with stable CHD was strongly reduced and was no longer statistically significant after controlling for potential confounders. We also found no independent association between the more virulent strains and CHD. In addition, a positive serostatus was not associated with a systemic inflammatory response. Thus, these data do not support the hypothesis that infection with H pylori might be a major risk factor for stable CHD.

Association between extent of periodontal attachment loss and self-reported history of heart attack: an analysis of NHANES III data

Coronary heart disease is responsible for one of every five deaths in the United States. Recent epidemiological studies have shown an association between periodontal disease and coronary heart disease. The purpose of this cross-sectional study was to verify this association using data from the third National Health and Nutrition Examination Survey (NHANES III). Data for 5564 people 40 years of age and older who had complete periodontal assessments and information on heart attack were evaluated. The outcome was the self-reported history of heart attack (yes vs. no). The main independent variable was the percent of periodontal sites per person with attachment loss of 3 mm or greater (categorized as 0%, > 0-33%, > 33-67%, and > 67%). Periodontal attachment loss was measured at two sites per tooth in randomly assigned half-mouths, one upper and one lower quadrant. The covariables included sociodemographic variables and established risk factors for cardiovascular disease. Relative to the 0% category, the unadjusted odds of heart attack increased with each higher category of attachment loss-2.2 (95% confidence interval = 1.3-3.8), 5.5 (3.4-9.1), and 9.8 (4.5-21.0), respectively. Adjustment for age, sex, race, poverty, smoking, diabetes, high blood pressure, body mass index, and serum cholesterol decreased these odds to 1.4 (0.8-2.5), 2.3 (1.2-4.4), and 3.8 (1.5-9.7), respectively. This study supports findings from previous studies of an association between periodontal disease and coronary heart disease.

Peroxisome proliferator-activated receptor alpha negatively regulates the vascular inflammatory gene response by negative cross-talk with transcription factors NF-kappaB and AP-1

Interleukin-6 (IL-6) is a pleiotropic cytokine, whose plasma levels are elevated in inflammatory diseases such as atherosclerosis. We have previously reported that peroxisome proliferator-activated receptor alpha (PPARalpha) ligands (fibrates) lower elevated plasma concentrations of IL-6 in patients with atherosclerosis and inhibit IL-1-stimulated IL-6 secretion by human aortic smooth muscle cells (SMC). Here, we show that aortic explants isolated from PPARalpha-null mice display an exacerbated response to inflammatory stimuli, such as lipopolysaccharide (LPS), as demonstrated by increased IL-6 secretion. Furthermore, fibrate treatment represses IL-6 mRNA levels in LPS-stimulated aortas of PPARalpha wild-type, but not of PPARalpha-null mice, demonstrating a role for PPARalpha in this fibrate action. In human aortic SMC, fibrates inhibit IL-1-induced IL-6 gene expression. Furthermore, activation of PPARalpha represses both c-Jun- and p65-induced transcription of the human IL-6 promoter. Transcriptional interference between PPARalpha and both c-Jun and p65 occurs reciprocally, since c-Jun and p65 also inhibit PPARalpha-mediated activation of a PPAR response element-driven promoter. This transcriptional interference occurs independent of the promoter context as demonstrated by cotransfection experiments using PPARalpha, p65, and c-Jun Gal4 chimeras. Overexpression of the transcriptional coactivator cAMP-responsive element-binding protein-binding protein (CBP) does not relieve PPARalpha-mediated transcriptional repression of p65 and c-Jun. Finally, glutathione S-transferase pull-down experiments demonstrate that PPARalpha physically interacts with c-Jun, p65, and CBP. Altogether these data indicate that fibrates inhibit the vascular inflammatory response via PPARalpha by interfering with the NF-kappaB and AP-1 transactivation capacity involving direct protein-protein interaction with p65 and c-Jun.

[Ischemic cardiopathy: inflammation markers and the cardiovascular risk]

In recent years it has been established that inflammation is a key mechanism in the pathogenesis of atherosclerosis and in coronary artery disease progression. Inflammation is a host response to a wide variety of tissue injuries. A persistent or continually repeated insult will lead to chronic inflammation which may result in tissue destruction and/or loss of normal organ function. Atherosclerosis and other pathologies involving inflammation are associated with increased levels of cytokines, which in turn raise acute-phase proteins levels in blood (acute inflammation markers, i.e. fibrinogen and C-reactive protein). It has been shown recently that concentrations of these proteins are higher in individuals at increased risk of developing cardiac events in the years to come. This is true both in apparently healthy men and women and in ischaemic heart disease patients. CRP is currently the inflammatory marker which appears to have captured the investigators' attention around the globe. In this report we review the current data on the relationship between atherosclerosis and inflammation, with special attention to cytokines and acute phase reactants. The use of acute phase reactants as prognostic risk markers in ischaemic heart disease is also discussed.

Chlamydia pneumoniae and anti-infective therapy: their role in the pathogenesis and treatment of coronary artery disease

Cardiovascular disease remains the most common cause of death in the United States; however, conventional cardiovascular risk factors fail to explain completely the pathogenesis of atherosclerosis and coronary artery disease. There has been recent interest in the association between Chlamydia pneumoniae and the risk of development or progression of atherosclerotic disease. This association has become evident through serologic, pathologic, and animal-based models and, more recently, through limited trials of antichlamydial antibiotics in humans. Whether C. pneumoniae is a causative agent or "innocent bystander" or whether antibiotic therapy has any role in the treatment of cardiovascular disease remains to be determined.

Plasma levels of interleukin 2, 6, 10 and phenotypic characterization of circulating T lymphocytes in ischemic heart disease

The purpose of this study was to assess lymphocyte receptors expression in patients with ischemic heart diseases, as well as to measure the plasma levels of interleukin (IL) 2, 6 and 10. T Lymphocytes are found in large numbers in human atherosclerotic plaques, indicating that immune and inflammatory mechanisms are important factors in the pathogenesis of atherosclerosis. Recent data have also implicated T lymphocytes in the pathogenetic mechanism of unstable angina and ischemic heart disease. Three groups of patients were studied: 42 with an acute ischemic syndrome (AIS), 36 with stable angina (SA) and 39 healthy controls. To characterize lymphocyte phenotype, flow cytometry was performed in whole-blood samples. IL-2, IL-6 and IL-10 were measured using the ELISA method. Double fluorescence evaluation showed an increase in CD8+/CD11b+ cells (cytotoxic T lymphocytes) and in CD11b+/CD16+CD56+ cells (NK lymphocytes) in the AIS group and in SA group as compared to the control group (P < 0.05 and P < 0.001, respectively). IL-2 was increased in the AIS and SA groups compared to the control group (AIS 4.5 +/- 0.5 pg/ml; SA 6.3 +/- 0.6 pg/ml; controls 2.4 +/- 0.8 pg/ml, P < 0.05), whereas IL-6 was higher in the AIS group than in the other two groups (AIS 10.8 +/- 1.8 pg/ml; SA 1.8 +/- 0.8 pg/ml; controls 1.2 +/- 0.6 pg/ml, P < 0.0001). These data show that patients with ischemic heart disease have an increase in circulating cytotoxic T lymphocytes and in IL-2 plasma levels, irrespective of their clinical presentation, compared to normal control subjects, whereas IL-6 is elevated only in patients with AIS.

Infection and atherosclerosis: emerging mechanistic paradigms

Although definitive proof of a causal role of infection contributing to atherogenesis is lacking, multiple investigations have demonstrated that infectious agents evoke cellular and molecular changes supportive of such a role. Moreover, both Chlamydia pneumoniae and cytomegalovirus exacerbate lesion development in animal models of atherosclerosis and restenosis. The fact that multiple pathogens have been associated with atherosclerosis implies that many "atherogenic" pathogens exist, and recent data suggest that the risk of atherosclerosis conveyed by infection relates to the number of atherogenic pathogens with which an individual is infected. It also is evident that variability in host susceptibility to the atherogenic effects of pathogens exists; this variability appears to be related at least in part to whether the host can generate an immune response that successfully controls pathogen inflammatory activity and in part to the specific pattern of immune response--humoral or cellular. The latter may relate to host capacity to control pathogen activity and to a pathogen-induced autoimmune component of the atherogenic process. Additional animal and human studies are necessary to further test the validity of the infection/atherosclerosis link and to provide more insight into the mechanisms by which infection may contribute to atherosclerosis, information critical for devising strategies to reduce or eliminate any contribution to atherosclerosis caused by infection.

A reactive oxygen-generating system activates nuclear factor-kappaB and releases tumor necrosis factor-alpha in coronary smooth muscle cells

BACKGROUND

Recently we reported that bacterial lipopolysaccharide (LPS) stimulates release of tumor necrosis factor alpha (TNF-alpha) from porcine coronary arteries and smooth muscle cells cultured from those vessels. It has also been reported that plasma levels of TNF-alpha are elevated after myocardial infarction. Since it is known that the production of reactive oxygen intermediates (ROI) occurs during ischemia and ROI are suggested activators of the nuclear regulatory factor kappaB (NF-kappaB), we tested the hypothesis that release of TNF-alpha from smooth muscle cells could also be stimulated with a ROI-generating system.

MATERIALS AND METHODS

Smooth muscle cells were isolated from porcine coronary arteries. Confluent cells in 48-well culture dishes were treated for 30 min with 0.003 units/ml xanthine oxidase (XO) and 2 mM hypoxanthine (HX) added to the culture medium. The medium was then removed and the cells were washed three times and fresh medium without HX-XO was added. Then, at 1, 3, and 6 h the medium was removed and analyzed for biologically active TNF-alpha. In other experiments, smooth muscle cells were treated with 20 micrograms/ml LPS for 6 h and aliquots of medium analyzed for TNF-alpha. Untreated cells served as controls. Data were analyzed by two-way ANOVA with repeated measures. Extracts of total cell protein were prepared and activation of NF-kappaB was determined by electrophoretic mobility shift assay.

RESULTS

Treatment of cells with HX-XO stimulated release of TNF-alpha, which rose to a maximum of 17.5 +/- 1.7 units/mg cell protein at 6 h. This was significantly higher (P < 0. 05) than release stimulated by LPS (10.2 +/- 1.0 units/mg at 6 h) or TNF-alpha detected in the culture medium from untreated control cells (4.2 +/- 0.9 units/mg protein at 6 h). Both HX/XO and LPS activated NF-kappaB.

CONCLUSIONS

These results support the conclusion that coronary smooth muscle cells are a potential source of TNF-alpha during events that are associated with formation of ROI such as myocardial ischemia.

Chlamydia pneumoniae, the Heart, and Coronary Artery Disease: Is There a Cause and Effect Relationship?

The possibility that infection with Chlamydia pneumoniae may somehow contribute to the pathogenesis of atherosclerosis continues to be explored by researchers worldwide. A direct cause-and-effect relationship between the bacterium and subsequent development of atherosclerosis has yet to be proved. However, compelling indirect evidence continues to mount in favor of this association. In this article the most recent information on this topic is reviewed. Seroepidemiologic and histopathologic evidence will be highlighted, as well as recent animal models of infection and atherosclerosis. In addition, current studies looking at the association of antichlamydial antibiotic use and risk of adverse cardiovascular outcomes will be detailed.

Chlamydia pneumoniae and coronary heart disease

OBJECTIVE

To review the potential association between Chlamydia pneumoniae (CP) infection and coronary artery disease (CAD), and to describe possible therapeutic interventions.

DATA SOURCES

A MEDLINE search of literature (January 1966-January 1998) pertaining to CP infection associated with heart disease was performed. Additional literature was obtained from review of journals and reference lists of pertinent articles identified through the search.

STUDY SELECTION AND DATA EXTRACTION

All articles involving CP and CAD were considered for possible inclusion in this review. Other selected articles involved possible links between infection and the atherosclerotic process, inflammation and inflammatory mediators in the atherosclerotic process, and isolation of CP from human tissue.

DATA SYNTHESIS

Numerous reports have suggested an association between chronic CP and CAD. CP has been seroepidemiologically linked to CAD. The organism has also been isolated from atherosclerotic lesions. Two reports in humans and one report in animals have shown that macrolide therapy (azithromycin or roxithromycin) may decrease the risk of adverse cardiovascular events.

CONCLUSIONS

Evidence seems to support an association between CP infection and an increased incidence of CAD. Additional and larger seroepidemiologic studies of this association need to be performed to establish a causal relationship between infection and CAD. Determination of the actual role of CP in CAD may decide the role of specific antichlamydial therapy in the management of this condition.

Characterization of low-density lipoprotein uptake by murine macrophages exposed to Chlamydia pneumoniae

Exposure to Chlamydia pneumoniae is correlated with atherosclerosis in a variety of clinical and epidemiological studies, but how the organism may initiate and promote the disease is poorly understood. One pathogenic mechanism could involve modulation of macrophage function by C. pneumoniae. We recently demonstrated that C. pneumoniae induces macrophages to accumulate excess cholesterol and develop into foam cells, the hallmark of early atherosclerotic lesions. To determine if C. pneumoniae-induced foam cell formation involved increased uptake of low-density lipoprotein (LDL), the current study examined macrophage association of a fluorescent carbocyanine (DiI)-labeled LDL following infection. C. pneumoniae enhanced the association of DiI-LDL with macrophages in a dose-dependent manner with respect to both C. pneumoniae and DiI-LDL. Interestingly, increased association was inhibited by native LDL and occurred in the absence of oxidation byproducts and in the presence of antioxidants. However, enhanced DiI-LDL association occurred without the participation of the classical Apo B/E native LDL receptor, since C. pneumoniae increased DiI-LDL association and induced foam cell formation in macrophages isolated from LDL-receptor-deficient mice. Surprisingly, DiI-LDL association was inhibited not only by unlabeled native LDL but also by high-density lipoprotein, very low density lipoprotein, and oxidized LDL. These data indicate that exposure of macrophages to C. pneumoniae increases the uptake of LDL and foam cell formation by an LDL-receptor-independent mechanism.

Chlamydia pneumoniae and atherosclerosis

OBJECTIVE

To review the literature for evidence that chronic infection with Chlamydia pneumoniae is associated with atherosclerosis and acute coronary syndromes.

DATA SOURCES

MEDLINE and Institute of Science and Information bibliographic databases were searched at the end of September 1998. Indexing terms used were chlamydi*, heart, coronary, and atherosclerosis. Serological and pathological studies published as papers in any language since 1988 or abstracts since 1997 were selected.

DATA EXTRACTION

It was assumed that chronic C pneumoniae infection is characterised by the presence of both specific IgG and IgA, and serological studies were examined for associations that fulfilled these criteria. Pathological studies were also reviewed for evidence that the presence of C pneumoniae in diseased vessels is associated with the severity and extent of atherosclerosis.

DATA SYNTHESIS

The majority of serological studies have shown an association between C pneumoniae and atherosclerosis. However, the number of cases in studies that have reported a positive association when using strict criteria for chronic infection is similar to the number of cases in studies which found no association. Nevertheless, the organism is widely found in atherosclerotic vessels, although it may not be at all diseased sites and is not confined to the most severe lesions. Rabbit models and preliminary antibiotic trials suggest that the organism might exacerbate atherosclerosis.

CONCLUSION

More evidence is required before C pneumoniae can be accepted as playing a role in atherosclerosis. Although use of antibiotics in routine practice is not justified, large scale trials in progress will help to elucidate the role of C pneumoniae.