Increased expression of neutrophil and monocyte adhesion molecules in unstable coronary artery disease

C-reactive protein and coronary artery disease

Evidence suggests that inflammation plays a key role in the pathogenesis of atherosclerosis. The chronic inflammatory process can develop to an acute clinical event by the induction of plaque rupture and therefore cause acute coronary syndromes. The aim of this study was to determine the serum levels of the circulating acute-phase reactant C-reactive protein (CRP), which is a sensitive indicator of inflammation, in patients with chronic stable coronary artery disease (CAD) and acute coronary syndromes (ACS). We studied 56 subjects: 1) 25 consecutive patients (18 men, 7 women; mean age, 68.5 +/- 14.3 years, range, 40-86) with unstable angina (UA) or acute myocardial infarction (AMI); 2) 31 consecutive patients (25 men, 6 women; mean age 64 +/- 12.7; range, 47-83, years) with signs and symptoms of clinically stable CAD. High-sensitivity-C-reactive protein (hs-CRP) levels were determined with a commercially available enzyme-linked immunoassay method. In patients with unstable angina and AMI before reperfusion therapy, CRP levels were not significantly different to those in patients with stable CAD (5.96 +/- 2.26 versus 4.35 +/- 2.6 mg/L; P = 0.12), but tended to be higher in patients with unstable angina and AMI. Baseline CRP levels in the subgroup of patients with AMI (6.49 +/- 2.28 mg/L) were significantly higher than levels in patients with stable CAD (4.35 +/- 2.6 mg/L; P = 0.02). CRP levels in patients with unstable angina and AMI were measured four times during a 72-hour period (0, 12, 24, and 72 hours). The lowest value was observed at baseline and differed significantly from values measured at any other time of the observation period (P < 0.001; 5.96 +/- 2.26; 9.5 +/- 9.04, 18.25 +/- 11.02; 20.25 +/- 10.61). CRP levels after 12, 24, and 72 hours were also significantly different to the initial values for patients with stable CAD (P < 0.01). There was no correlation between CRP and creatine kinase (CK), CK-MB isoenzyme, or troponin I positivity as markers for the extent of the myocardial injury during the observation period. Baseline levels of serum CRP tended to be higher in patients with unstable angina or AMI but were not significantly different from levels in patients with chronic stable CAD. In the subgroup of patients with AMI, baseline CRP levels were significantly higher than the levels in patients with stable CAD. CRP as a marker of inflammation is significantly increased in patients with AMI and unstable angina shortly after the onset of symptoms (after a period of 12 hours), supporting the hypothesis of an activation of inflammatory mechanisms in patients with an acute coronary syndrome or AMI.

Inflammation and immune system response against unstable angina and its relationship with coronary angiographic findings

The aim of this study was to assess the relations between inflammation, immune response, and coronary angiographic findings in patients with unstable angina pectoris (UAP). Recent studies suggest a role for inflammation in the pathophysiology of UAP. Although activation of neutrophils, monocytes and lymphocytes has been shown in UAP, no studies have correlated the activation findings with clinical and angiographic features of patients with UAP. Seventy-three patients undergoing coronary angiography were classified according to their ischaemic syndrome, stable angina pectoris (SAP) (n = 25) and UAP (n = 48). Patients with UAP were classified using the Braunwald classification; UAP class I (n = 15), UAP class II (n = 15), and UAP class III (n = 18). Patients with UAP were also classified into a progression to myocardial infarction (MI (+)) group (n = 15) and a non-progression to myocardial infarction (MI(-)) group (n = 33). Venous blood samples were taken from all patients. Cell surface receptors (CD4, CD8, CD3, CD14, CD45, CD56+16, and HLA-DR) were detected by flow cytometry using monoclonal antibodies tagged with fluorescent markers and serum levels of C-reactive protein (CRP) were measured. The serum levels of CRP and the percentages of HLA-DR, CD14, and CD16+56 were higher in UAP than SAP. The serum levels of CRP and percentages of HLA-DR, CD14, and CD16+56 were higher in UAP class II than UAP class I. The serum levels of CRP and percentages of HLA-DR, CD14, and CD16+56 were higher in UAP class III than UAP class II and UAP class I. The serum levels of CRP and percentages of CD16+56 were higher in the MI(+) group than the MI(-) group. The CRP levels in serum and the percentages of cell surface antigens had no correlation with extent of coronary artery disease (no differences among one, two or three vessels) but Type C lesion had significantly higher percentages of HLA-DR, CD14, CD16+56 and the serum levels of CRP than Type A and Type B lesions. This investigation shows that inflammatory and immunologial components may be detectable in UAP and were correlated with the clinical severity, progression to myocardial infarction, and lesion morphology, but were not correlated with the extent of coronary artery disease.

Elevation of serum levels of the anti-inflammatory cytokine interleukin-10 and decreased risk of coronary events in patients with unstable angina

BACKGROUND

Inflammation is an important phenomenon in atherosclerotic plaque growth and in plaque instability. Cytokines are nuclear mediators in the inflammatory response; some have proinflammatory and others anti-inflammatory roles. Proinflammatory cytokines have been associated with worse outcomes in unstable angina. The aims of this study were to determine the role of the anti-inflammatory cytokine interleukin (IL)-10 and the proinflammatory to anti-inflammatory ratios in the short-term prognosis of patients with unstable angina.

METHODS

Serum levels of proinflammatory cytokines IL-1beta, IL-6, and IL-8, and of the anti-inflammatory cytokine IL-10 were determined on admission in 127 consecutive patients with severe unstable angina, and comparisons were made between patients who had cardiovascular events (death, nonfatal myocardial infarction, readmission for refractory angina) (n = 20) and patients without coronary events (n = 107) during a follow-up period of 3 months.

RESULTS

IL-10 levels were lower (0.67 +/- 1.13 vs 1.33 +/- 1.67 pg/mL, P =.04) and IL-8 levels were higher (3.6 +/- 2.41 vs 2.23 +/- 2.47 pg/mL, P =.029) in patients in whom cardiovascular events subsequently developed compared with those without events, with resulting higher proinflammatory to anti-inflammatory cytokine ratios in the former group, whereas no significant differences were seen in IL-1beta or IL-6 levels between the groups, except for the subgroup of patients with prolonged rest angina and persistent electrocardiographic changes. A greater ratio of IL-8 to IL-10 serum levels was observed in patients who had coronary events (28 +/- 25 vs 12 +/- 21, P =.007). The risk of subsequent coronary events increased in patients in the highest quartile of proinflammatory to anti-inflammatory cytokine ratio (IL-8/IL-10). Patients in the highest quartile had a relative risk 3.8 times higher than those in the lowest quartile (P =.01).

CONCLUSIONS

Lower levels of IL-10, with higher proinflammatory to anti-inflammatory cytokine ratios, were observed on admission in patients with unstable angina who subsequently had cardiovascular events. Higher levels of the anti-inflammatory cytokine IL-10 may be needed to provide protection in unstable angina.

The GP IIb/IIIa inhibitor abciximab (c7E3) inhibits the binding of various ligands to the leukocyte integrin Mac-1 (CD11b/CD18, alphaMbeta2)

Cross-reactivity with integrins other than glycoprotein IIb/IIIa (GP IIb/IIIa) is discussed as a potential reason for the overall clinical benefits of the GP IIb/IIIa-blocking antibody-fragment abciximab. We evaluated whether abciximab binds to the leukocyte integrin Mac-1, whether it inhibits binding of the distinct ligands and thereby may modulate inflammation, cell proliferation and coagulation. Binding of fluorescence-labelled abciximab to phorbolmyristate acetate-stimulated monocytes and to a monocytic cell line (THP-1) could be detected in flow cytometry. The binding of fibrinogen, the inactivated complement factor 3b (iC3b), and the coagulation factor X to Mac-1 could be inhibited by abciximab (10 microg/ml) in vitro. As a functional consequence, the conversion of factor X to factor Xa mediated by Mac-1, as detected by the chromogenic substrate SZ-2222, was impaired by abciximab. Adhesion of THP-1 cells to immobilized intercellular adhesion molecule 1 (ICAM-1) and to fibrinogen was reduced significantly by abciximab. Fibrinogen-mediated cell aggregation was also impaired. In conclusion, we describe binding of abciximab to Mac-1 on stimulated monocytes. Thereby, abciximab inhibits binding of the ligands fibrinogen, ICAM-1, iC3b and factor X. Furthermore, we demonstrated that Mac-1-dependent conversion from factor X to factor Xa is impaired by abciximab, arguing for the direct modulation of the coagulation cascade by abciximab. Overall, the inhibition of Mac-1 could provide additional clinical benefits of abciximab beyond the well-described blockade of GP IIb/IIIa.

Widespread coronary inflammation in unstable angina

BACKGROUND

Inflammation within vulnerable coronary plaques may cause unstable angina by promoting rupture and erosion. In unstable angina, activated leukocytes may be found in peripheral and coronary-sinus blood, but it is unclear whether they are selectively activated in the vascular bed of the culprit stenosis.

METHODS

We measured the content neutrophil myeloperoxidase content in the cardiac and femoral circulations in five groups of patients: two groups with unstable angina and stenosis in either the left anterior descending coronary artery (24 patients) or the right coronary artery (9 patients); 13 with chronic stable angina; 13 with variant angina and recurrent ischemia; and 6 controls. Blood samples were taken from the aorta, the femoral vein, and the great cardiac vein, which selectively drains blood from the left but not the right coronary artery.

RESULTS

The neutrophil myeloperoxidase content of aortic blood was similar in both groups of patients with unstable angina (-3.9 and -5.5, with negative values representing depletion of the enzyme due to neutrophil activation) and significantly lower than in the other three groups (P<0.05). Independently of the site of the stenosis, the neutrophil myeloperoxidase content in blood from the great cardiac vein was significantly decreased in both groups of patients with unstable angina (-6.4 in those with a left coronary lesion and -6.6 in those with a right coronary lesion), but not in patients with stable angina and multiple stenoses, patients with variant angina and recurrent ischemia, or controls. There was also a significant transcoronary reduction in myeloperoxidase content in both groups with unstable angina.

CONCLUSIONS

The widespread activation of neutrophils across the coronary vascular bed in patients with unstable angina, regardless of the location of the culprit stenosis, challenges the concept of a single vulnerable plaque in unstable coronary syndromes.

Elevated soluble CD40 ligand is related to the endothelial adhesion molecules in patients with acute coronary syndrome

BACKGROUND

Increasing evidence indicates that the CD40-CD40L interaction plays a pivotal role in the inflammatory regulation of atherosclerosis. Adhesion molecules especially the vascular adhesion molecules also play an important role in the pathogenesis of atherosclerosis which act as markers of inflammation. These inflammatory factors render vulnerability to the atherosclerotic plaque by triggering the fissure, rupture, and subsequent thrombosis, leading to the clinical scenario of unstable angina and acute myocardial infarction.

METHODS

The difference of sCD40L concentration in different subtype of coronary heart disease and its relationship with vascular adhesion molecules was investigated. Enzyme-linked Immunosorbent Assay (EIA) was used to measure the serum sCD40L, soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1).

RESULTS

The sCD40L concentration was significantly higher in patients with acute coronary syndrome (ACS) (3.17+/-2.84 ng/ml) than in controls (1.19+/-1.05 ng/ml, p<0.01) and in patients with stable coronary heart disease (1.61+/-1.46 ng/ml, p<0.05). The sCD40L concentration was positively correlated with sICAM-1 (r=0.413, p<0.01), triglycerides (TG) (r=0.23, p<0.05), apoB (r=0.248, p<0.05), and HDL-cholesterol (r=-0.253, p<0.05).

CONCLUSIONS

The sCD40L concentration was increased in acute coronary syndrome, suggesting the possible relation of CD40L to the pathogenesis. The serum CD40L concentration was positively correlated with adhesion molecule and was negatively associated with serum high-density lipoprotein cholesterol (HDL-C).

Elevated level of plasma C-reactive protein in patients with unstable angina: its relations with coronary stenosis and lipid profile

C-reactive protein (CRP) is a sensitive marker of inflammation, and elevated levels have been associated with future risk of cardiovascular events. To explore the role and relationship of CRP and coronary stenosis in the development of unstable angina (UA), plasma levels of CRP were determined on admission in 45 patients with UA, and in 42 patients with stable angina (SA) using high-sensitivity ELISA. Coronary angiography was performed in all patients with coronary heart disease (CHD), and severity of coronary stenosis was evaluated by a quantitative analysis. Lipid measurement was performed using automatic biochemical analyzer. Data available from patients with CHD were compared with those of 41 control subjects. The results showed that plasma levels of CRP are significantly higher in patients with UA than those in patients with SA and control subjects (5.1 +/- 1.4 mg/L vs 1.7 +/- 0.4 mg/L and 1.3 +/- 0.2 mg/L, p<0.01, respectively) with no difference between the latter two groups (p>0.05); the total incidence of clinical events during in-hospital follow-up was higher in the group A (p<0.01); the scores of coronary stenosis are significantly higher in patients with SA than those in patients with UA (4.9 +/- 2.1 vs 3.4 +/- 1.4, p<0.05); there is no correlation between plasma levels of CRP and serum total cholesterol (TC) as well as high-density lipoprotein cholesterol (HDL-C) in both groups (p>0.05 respectively); there was no correlation between plasma levels of CRP and severity of coronary stenosis was found in patients with UA (p>0.05) but a significant positive association in patients with SA (p<0.001); and the patients with persistent, severe, treatment-unresponsive UA had significantly higher CRP levels as well as incidence of clinical events than patients with treatment-responsive UA (7.4 +/- 1.8 mg/L vs 2.6 +/- 1.3 mg/L, p<0.01; 0 vs 22.2%, p<0.05). The present data suggested that inflammation may play an important role in the pathogenesis of UA, and the plasma levels of CRP might have a higher prognostic value than the severity of coronary stenosis correlated with the clinical outcome of instability despite of lipid profile status.

Platelet and leukocyte activation during aortoiliac angiography and angioplasty

OBJECTIVE

to evaluate platelet and leukocyte activation during aortoiliac angiography and percutaneous transluminal angioplasty (PTA).

METHODS

an observational study of 14 patients with aortoiliac atherosclerotic disease, nine of whom underwent PTA. The proportion of fibrinogen-, and P-selectin positive platelets, P-selectin expression on platelets, intraplatelet cGMP and cAMP, CD18 positive granulocytes, CD18 expression on granulocytes, plasma (p)-neopterin, p-TNF alpha and p- interleukin-6 were repeatedly measured in arterial blood during angiography and in venous blood before and after.

RESULTS

compared to a previous venous sample, arterial intraplatelet cAMP was increased proximal to the atherosclerotic lesion before contrast infusion and PTA (median 18 [range: 14-22] vs 16 [15-21] pmol/10(9) platelets p<0.05), and intraplatelet cGMP was increased proximal to the lesion after contrast infusion and PTA (1.2 [0.8-3.9] vs 0.9 [0.6-2.5] pmol/10(9) platelets p<0.05). Four hours after angiography, both the proportion of P-selectin positive platelets (28[11-55]%) and platelet P-selectin expression (9[6-40]) had decreased (p<0.05), from arterial values distal to the lesion before contrast infusion and PTA (57 [24-78]% and 26 [10-83]). Granulocyte CD18 expression was lower during angiography than in a previous venous sample.

CONCLUSIONS

the results are compatible with platelet but not leukocyte activation during peripheral angiography.

Inflammation in acute coronary syndromes

Extensive evidence supports a pathogenic role for both local and systemic inflammation in acute coronary syndromes. However, several important questions remain unanswered. Is the observed inflammatory process a precursor or a consequence of coronary plaque rupture? Is the inflammatory component of unstable coronary disease a potential therapeutic target? Finally, do infectious agents have a pathogenic role in coronary atherosclerosis and acute coronary syndromes?

Normal pregnancy is associated with peripheral leukocyte activation

PROBLEM

Normal pregnancy has been described as both a pro-inflammatory condition and a T helper (Th)2-dominated state. Deviations in the percentage of different subpopulations of circulating leukocytes have been detected, although with conflicting results. This study was designed to analyse further the phenotype of subpopulations of peripheral blood leukocytes in normal pregnant women.

METHOD OF STUDY

Whole-blood flow cytometry was used to differentiate subsets of leukocytes using directly labeled monoclonal antibodies to specific cell surface antigens and to a panel of activation-associated markers in 33 normal pregnant women in their third trimester and in 26 non-pregnant controls.

RESULTS

We found a significant increase in the proportion of granulocytes and of CD8+ T lymphocytes during pregnancy. Up-regulation of the expression of adhesion molecules was observed on granulocytes, monocytes and T lymphocytes.

CONCLUSIONS

Pregnancy alters the representation of leukocyte subpopulations in the maternal circulation and is associated with systemic activation of leukocytes.

Increased production of inflammatory cytokines in patients with silent myocardial ischemia

OBJECTIVES

The aim of the study was to examine the inflammatory cytokines in patients with myocardial ischemia to evaluate whether silent ischemia patients exhibit any particular cytokine pattern.

BACKGROUND

Silent myocardial ischemia is frequently observed in patients with coronary artery disease. Various endogenous mechanisms control a patient's perceived intensity of pain. Among them, the inflammatory process and the related cytokine production are known to modulate the threshold for activating the primary afferent nociceptors.

METHODS

Seventy-eight patients with reproducible exercise-induced myocardial ischemia were studied: 34 symptomatic patients, with rest and/or stress angina; 44 asymptomatic patients, with no symptoms during daily life activities or during positive exercise stress test. Venous blood samples were taken from all patients to evaluate the expression of CD11b receptors both on neutrophils and monocytes. Frozen plasma samples (at -80 degrees C) were used to quantify the anti-inflammatory (interleukin-4 and -10, transforming growth factor-beta) and the proinflammatory cytokines (tumor necrosis factor-alpha, interferon-gamma, interleukin-1beta and -6).

RESULTS

In asymptomatic patients lower CD11b receptor expression and higher concentration of anti-inflammatory cytokines were observed. Proinflammatory cytokine production was similar in the two groups.

CONCLUSIONS

The data suggest that an "anti-inflammatory pattern" of cytokine production correlates with silent ischemia and that the immune and inflammatory system activation may be crucial for angina symptoms.

Patients with acute coronary syndromes express enhanced CD40 ligand/CD154 on platelets

OBJECTIVE

To investigate whether CD40L/CD154 on platelets and soluble CD40L/CD154 may play a role in the inflammatory process of acute coronary syndromes.

DESIGN AND SETTING

Observational study in a university hospital.

PATIENTS

15 patients with acute myocardial infarction, 25 patients with unstable angina, 15 patients with stable angina, and 12 controls.

MAIN OUTCOME MEASURES

CD40L/CD154 on platelets, P-selectin/CD62P on platelets, soluble CD40L/CD154 serum concentrations.

RESULTS

Mean (SD) CD40L/CD154 expression on platelets was 6.2 (2.8) MFI (mean fluorescence intensity) in the infarct group, 11 (3.3) MFI in the unstable angina group (p < 0.001 v infarction), 3.6 (0.9) MFI in the stable angina group (p < 0.01 v infarction; p < 0.001 v unstable angina), and 3.2 (1.0) MFI in the controls (p < 0.01 v infarction; p < 0.001 v unstable angina; NS v stable angina). Soluble CD40L/CD154 concentration was 5.2 (1.1) ng/ml in the infarct group, 4.2 (0.7) ng/ml in the unstable angina group (p < 0.001 v infarction), 2.9 (1.0) ng/ml in stable angina group (p < 0.001 v infarction and unstable angina), and 3.0 (0.5) ng/ml in the controls (p < 0.001 v infarction and unstable angina; NS v stable angina). At a six months follow up, there was lower expression of CD40L/CD154 on platelets in patients with unstable angina (12.3 (3.6) v 3.8 (1.2) MFI, p < 0.0001) and acute myocardial infarction (6.2 (2.8) v 3.5 (0.8) MFI, p < 0.01) compared with their admission values six months earlier. Patients with unstable angina who needed redo coronary angioplasty (PTCA) or who had recurrence of angina were characterised by increased CD40L/CD154 expression on platelets compared with the remainder of the study group (recurrence of angina: 12.7 (3.2) v 9.7 (1.6) MFI, p < 0.05; re-do PTCA: 14.3 (4.2) v 10.3 (2.1) MFI, p < 0.05).

CONCLUSIONS

Both CD40L/CD154 on platelets and soluble CD40L/CD154 are raised in patients with unstable angina and myocardial infarction. These findings suggest that CD40-CD40L/CD154 interactions may play a pathogenic role in triggering and propagation of acute coronary syndromes.

Enhanced endothelial activation in diabetic patients with unstable angina and non-Q-wave myocardial infarction

AIMS

Diabetes mellitus (DM) is associated with chronic endothelial dysfunction. Diabetic patients presenting with acute coronary syndromes have a worse prognosis than non-diabetics. An acute inflammatory reaction at the site of coronary plaque rupture and increased expression of surface and soluble cellular adhesion molecules (CAMs) are pathological features of acute coronary syndromes. We set out to characterize the expression of soluble CAMs in patients with and without diabetes presenting with unstable angina (UA) and non Q-wave myocardial infarction (NQMI).

METHODS

Patients presenting with UA and NQMI had serum samples taken on presentation, after 72 h and then 3, 6 and 12 months after discharge. Levels of soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin and P-selectin were measured using an ELISA technique.

RESULTS

We studied 15 diabetic patients and 15 age- and sex-matched non-diabetic patients presenting with either UA or NQMI. Levels of soluble E-selectin were elevated in the diabetic patients in comparison with the non-diabetic patients at all measured time points: 74 +/- 10 ng/ml vs. 47 +/- 3 ng/ml, P < 0.03 at t = 0 h, 55 +/- 5 ng/ml vs. 38 +/- 2 ng/ml, P < 0.02 at t = 72 h. However, levels of soluble P-selectin were lower in the diabetic cohort during follow-up: 134 +/- 15 ng/ml vs. 225 +/- 32 ng/ml, P < 0.02 at t = 3/12 and 112 +/- 8 ng/ml vs. 197 +/- 23 ng/ml, P < 0.02 at t = 6/12. There was no significant difference in levels of soluble ICAM-1 and VCAM-1 between diabetic and non-diabetic patients.

CONCLUSIONS

Levels of soluble E-selectin are significantly elevated in diabetic patients presenting with UA and NQMI in comparison with non-diabetics. This finding may reflect enhanced endothelial activation which may contribute to the adverse prognosis of diabetic patients with acute coronary syndromes.

Increased circulating monocyte activation in patients with unstable coronary syndromes

OBJECTIVES

The primary objective of this research was to assess the activation level of circulating monocytes in patients with unstable angina.

BACKGROUND

Markers of systemic inflammatory responses are increased in patients with unstable coronary syndromes, but the activation state and invasive capacity of circulating monocytes have not been directly assessed.

METHODS

Peripheral blood mononuclear cell (MC) activation in blood samples isolated from patients with stable and unstable coronary artery disease was measured in two studies. In study 1, a modified Boyden chamber assay was used to assess spontaneous cellular migration rates. In study 2, optical analysis of MC membrane fluidity was correlated with soluble CD14 (sCD14), a cellular activation marker.

RESULTS

Increased rates of spontaneous monocyte migration (p < 0.01) were detected in patients with unstable angina (UA) (Canadian Cardiovascular Society [CCS] angina class IV) on comparison to patients with acute myocardial infarction (MI), stable angina (CCS angina classes I to III) or normal donors. No significant increase in lymphocyte migration was detected in any patient category. Baseline MC membrane fluidity measurements and sCD14 levels in patients with CCS class IV angina were significantly increased on comparison with MCs from normal volunteers (p < 0.001). A concomitant reduction in the MC response to activation was detected (p < 0.05).

CONCLUSIONS

Using two complementary assays, activated monocytes with increased invasive capacity were detected in the circulation of patients with unstable angina. This is the first demonstration of increased monocyte invasive potential in unstable patients, raising the issue that systemic inflammation may both reflect and potentially drive plaque instability.

Cigarette smoking and hypertension influence nitric oxide release and plasma levels of adhesion molecules

Progression of atherosclerosis is currently believed to involve interactions between leukocytes and vascular endothelium. Epidemiological risk factors for atherosclerosis such as hypertension and smoking are known to cause endothelial dysfunction, which is an early event in the atherosclerotic process; they also may be considered in the light of their effects on adhesion molecule expression and release. Little is known about the additive effect between these two risk factors on endothelial adhesion molecule expression and nitric oxide release. Soluble adhesion molecules and the nitric oxide were quantified in smoking hypertensive patients in comparison to those from patients with hypertension alone. Cotinine, a stable metabolite of nicotine, has been used to identify smokers. One hundred and three hypertensive patients were selected: 51 smokers (plasma cotinine levels >25 ng/ml) and 52 non-smokers. Plasma concentrations of soluble intercellular cell adhesion molecule-1 (sICAM-1), soluble endothelial leukocyte adhesion molecule-1 (sELAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-I) were quantified with ELISA methods. Plasma concentration of nitric oxide metabolites was measured by HPLC, whilst plasma concentration of cotinine was measured by RIA. Significant increases of sICAM-1 and sVCAM-1 were demonstrated in smokers (p<0.001 and p<0.05, respectively). In the same patients, a positive significant correlation between sVCAM-1 and plasma cotinine levels was observed (p<0.002). Nitric oxide metabolites were reduced significantly (p<0.04) in smokers. In conclusion, our data show that the two risk factors, smoking and hypertension, are additive risk factors in generating endothelial dysfunction and vascular damage, which plays a key role in atherogenesis.

Monocytic cell adhesion to intact and plasmin-modified fibrinogen: possible involvement of Mac-1 (CD11b/CD18) and ICAM-1 (CD54)

beta(2)-integrin Mac-1 and immunoglobulin-like ICAM-1 adhesion molecules are expressed by monocytes and both known to bind fibrinogen and its degradation products. Here, we investigated whether fibrinogen cleavage with plasmin modulates the adherence of monocytic cells and what types of adhesion molecules are involved. Using several cell types, characterized by different patterns of Mac-1 and ICAM-1 expression, and monoclonal antibodies against beta(2)-integrins and ICAM-1 we demonstrate, that fibrinogen cleavage evokes gradual decrease in beta(2)-integrin-dependent cell adhesion. Furthermore, generation of the early degradation products, fragments X and Y, by minimum cleavage of fibrinogen stimulates cell adhesion, mediated by ICAM-1.

Different effects of antisense RelA p65 and NF-kappaB1 p50 oligonucleotides on the nuclear factor-kappaB mediated expression of ICAM-1 in human coronary endothelial and smooth muscle cells

BACKGROUND

Activation of nuclear factor-kappaB (NF-kappaB) is one of the key events in early atherosclerosis and restenosis. We hypothesized that tumor necrosis factor-alpha (TNF-alpha) induced and NF-kappaB mediated expression of intercellular adhesion molecule-1 (ICAM-1) can be inhibited by antisense RelA p65 and NF-kappaB1 p50 oligonucleotides (RelA p65 and NF-kappaB1 p50).

RESULTS

Smooth muscle cells (SMC) from human coronary plaque material (HCPSMC, plaque material of 52 patients), SMC from the human coronary media (HCMSMC), human endothelial cells (EC) from umbilical veins (HUVEC), and human coronary EC (HCAEC) were successfully isolated (HCPSMC, HUVEC), identified and cultured (HCPSMC, HCMSMC, HUVEC, HCAEC). 12 hrs prior to TNF-alpha stimulus (20 ng/mL, 6 hrs) RelA p65 and NF-kappaB1 p50 (1, 2, 4, 10, 20, and 30 microM) and controls were added for a period of 18 hrs. In HUVEC and HCAEC there was a dose dependent inhibition of ICAM-1 expression after adding of both RelA p65 and NF-kappaB1 p50. No inhibitory effect was seen after incubation of HCMSMC with RelA p65 and NF-kappaB1 p50. A moderate inhibition of ICAM-1 expression was found after simultaneous addition of RelA p65 and NF-kappaB1 p50 to HCPSMC, no inhibitory effect was detected after individual addition of RelA p65 and NF-kappaB1 p50.

CONCLUSIONS

The data point out that differences exist in the NF-kappaB mediated expression of ICAM-1 between EC and SMC. Experimental antisense strategies directed against RelA p65 and NF-kappaB1 p50 in early atherosclerosis and restenosis are promising in HCAEC but will be confronted with redundant pathways in HCMSMC and HCPSMC.

Risk stratification in unstable angina and non-Q wave myocardial infarction using soluble cell adhesion molecules

OBJECTIVE

To assess prospectively the prognostic value of soluble cellular adhesion molecules (CAMs) in patients with unstable angina and non-Q wave myocardial infarction and to compare their prognostic accuracy with that of C reactive protein (CRP).

DESIGN AND SETTING

Prospective observational study of patients presenting acutely with unstable angina and non-Q wave myocardial infarction to a single south Dublin hospital.

METHODS

Patients with Braunwald IIIA unstable angina and non-Q wave myocardial infarction had serum samples taken at presentation before initiation of antithrombotic treatment and were followed for six months. The primary end point was the occurrence of major adverse cardiovascular events (recurrent unstable angina, non-fatal myocardial infarction, and cardiovascular death) at six months. Concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble endothelial selectin, and soluble platelet selectin were measured using an enzyme linked immunosorbent assay technique. CRP was measured with an immunophelometric assay.

RESULTS

91 patients (73 men and 18 women, mean (SD) age 61 (11) years) were studied; 27 patients (30%) had major adverse cardiac events during the six months of follow up. Concentration of CRP were significantly raised in patients who had an ischaemic event (mean (SEM) 11.5 (6.4) mg/l v 5.4 (2.5) mg/l, p < 0.001). Concentrations of sVCAM-1 were also significantly raised in the ischaemic event group (979 (30) ng/ml v 729 (22) ng/ml, p < 0.001). Both sVCAM-1 and CRP concentrations correlated strongly with the occurrence of an adverse event. The sensitivity of CRP > 3 mg/l and sVCAM-1 > 780 ng/ml for predicting future events was > 90%. There was no difference in concentrations of sICAM-1, soluble endothelin selectin, or soluble platelet selectin between event and non-event groups.

CONCLUSION

Raised concentrations of sVCAM-1 and CRP are predictive of an increased risk of major adverse cardiovascular events six months after presentation with unstable angina and non-Q wave myocardial infarction. These findings suggest that the intensity of the vascular inflammatory process at the time of presentation is a determinant of clinical outcome in unstable coronary artery disease.

Increased concentrations of inflammatory mediators in unstable angina: correlation with serum troponin T

OBJECTIVE

To measure plasma interferon γ, monocyte chemotactic protein-1 (MCP-1), and interleukin 6 and to assess their correlation with cardiac troponin T in unstable angina.

DESIGN

Blood sampling in patients undergoing coronary arteriography for known or suspected ischaemic heart disease.

PATIENTS

76 patients divided in three groups: 29 with unstable angina (group 1), 28 with stable angina (group 2), and 19 without ischaemic heart disease and with angiographically normal coronary arteries (group 3).

MAIN OUTCOME MEASURES

Plasma interleukin 6, interferon γ, MCP-1, and troponin T in the three groups of patients.

RESULTS

Interleukin 6 was increased in group 1 (median 2.19 (range 0.53–50.84) pg/ml) compared with the control group (1.62 (0.79–3.98) pg/ml) (p < 0.005), whereas interferon γ was higher in group 1 (range 0–5.51 pg/ml) than in the other two groups (range 0–0.74 pg/ml and 0–0.37 pg/ml; p < 0.005 and p < 0.001, respectively). Patients with unstable angina (group 1) and positive troponin T had higher concentrations of interferon γ than those with negative troponin T (0–5.51 pg/mlv 0–0.60 pg/ml, p < 0.001). Plasma MCP-1 was also higher in group 1 (median 267 (range 6–8670) pg/ml) than in the other two groups (134 (19–890) pg/ml and 84.5 (5–325) pg/ml; p < 0.005 and p < 0.001, respectively), and among group 1 patients with a positive troponin T assay than in those with normal troponin T (531 (14.5–8670) pg/mlv 69 (6–3333) pg/ml; p < 0.01). There was no difference in plasma interleukin 6 in group 1 patients between those with and without raised troponin T.

CONCLUSIONS

The inflammatory cytokines interferon γ and MCP-1 are increased in patients with unstable angina, particularly in those with raised concentrations of troponin T, suggesting that they are probably related to myocardial cell damage or to plaque rupture and thrombus formation.

Increased concentrations of inflammatory mediators in unstable angina: correlation with serum troponin T

OBJECTIVE

To measure plasma interferon gamma, monocyte chemotactic protein-1 (MCP-1), and interleukin 6 and to assess their correlation with cardiac troponin T in unstable angina.

DESIGN

Blood sampling in patients undergoing coronary arteriography for known or suspected ischaemic heart disease.

PATIENTS

76 patients divided in three groups: 29 with unstable angina (group 1), 28 with stable angina (group 2), and 19 without ischaemic heart disease and with angiographically normal coronary arteries (group 3).

MAIN OUTCOME MEASURES

Plasma interleukin 6, interferon gamma, MCP-1, and troponin T in the three groups of patients.

RESULTS

Interleukin 6 was increased in group 1 (median 2.19 (range 0.53-50.84) pg/ml) compared with the control group (1.62 (0.79-3.98) pg/ml) (p < 0.005), whereas interferon gamma was higher in group 1 (range 0-5.51 pg/ml) than in the other two groups (range 0-0.74 pg/ml and 0-0.37 pg/ml; p < 0.005 and p < 0.001, respectively). Patients with unstable angina (group 1) and positive troponin T had higher concentrations of interferon gamma than those with negative troponin T (0-5.51 pg/ml v 0-0.60 pg/ml, p < 0.001). Plasma MCP-1 was also higher in group 1 (median 267 (range 6-8670) pg/ml) than in the other two groups (134 (19-890) pg/ml and 84.5 (5-325) pg/ml; p < 0.005 and p < 0.001, respectively), and among group 1 patients with a positive troponin T assay than in those with normal troponin T (531 (14.5-8670) pg/ml v 69 (6-3333) pg/ml; p < 0.01). There was no difference in plasma interleukin 6 in group 1 patients between those with and without raised troponin T.

CONCLUSIONS

The inflammatory cytokines interferon gamma and MCP-1 are increased in patients with unstable angina, particularly in those with raised concentrations of troponin T, suggesting that they are probably related to myocardial cell damage or to plaque rupture and thrombus formation.

Unstable angina pectoris and non-Q-wave myocardial infarction

Unstable angina pectoris and non-Q-wave myocardial infarction are clinical syndromes that share many pathophysiologic and clinical features. In the spectrum of coronary artery disease, these syndromes lie between chronic stable angina and Q-wave myocardial infarction. Although both conditions are associated with significant morbidity and mortality, patients presenting with these syndromes can be further risk stratified into higher and lower risk based on a number of readily available clinical features and biochemical parameters. Such risk stratification can allow for more tailored treatment and better resource allocation. Although routine early coronary angiography and revascularization has not been shown to be superior to conservative management, certain high-risk patients may benefit from a more aggressive strategy. Medical therapy with the use of antiplatelet, anticoagulant, and antiischemic agents remains the cornerstone of emergent treatment for patients presenting with these syndromes. The recent demonstration of a reduction in both morbidity and mortality with the glycoprotein IIb/IIIa antagonists has further expanded the armamentarium of available agents. Following initial stabilization, risk stratification with stress testing can help identify patients with a large residual ischemic burden who may benefit from coronary angiography with revascularization if feasible.

Interaction between chemokines and oxidative stress: possible pathogenic role in acute coronary syndromes

OBJECTIVES

We sought to study the relationships between chemokines and oxidative stress in acute coronary syndrome.

BACKGROUND

In view of existing knowledge on the participation of leukocytes and oxidative stress in the pathogenesis of acute coronary syndrome, we hypothesized that chemokines may play a role in recruiting and activating leukocytes in this disorder.

METHODS

The levels of chemokines and oxidative stress were studied in 38 patients with stable and 38 with unstable angina and in 20 controls. In separate in vitro experiments the effect of chemokines on reactive oxygen species in monocytes and the effect of antioxidants on chemokine levels in these cells were also studied.

RESULTS

1) Angina patients had raised serum levels of chemokines in both cross-sectional and longitudinal testing, with particularly high levels of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory peptide (MIP)-1-alpha in unstable disease. 2) T cells, and particularly monocytes, seem to contribute to the raised IL-8, MCP-1 and MIP-1-alpha levels in unstable angina. 3) Concomitantly, and significantly correlated with MCP-1 and IL-8 levels, stable and particularly unstable angina patients had decreased plasma levels of antioxidants and increased lipid peroxidation, suggesting enhanced oxidative stress. 4) Monocyte chemoattractant protein-1 enhanced the generation of O2- in monocytes from unstable angina patients, and the antioxidant glutathione-monoethyl ester suppressed the production of IL-8 and MCP-1 in these cells.

CONCLUSIONS

Our findings suggest an interaction between chemokines and oxidative stress in unstable angina. This interaction may represent a vicious circle involved in the pathogenesis of acute coronary syndromes.

Evidence of prolonged inflammation in unstable angina and non-Q wave myocardial infarction

OBJECTIVES

This study was designed to document the inflammatory response up to one year after acute presentation with unstable angina (UA) and non-Q wave infarction (NQMI) as reflected by the expression of soluble cell adhesion molecules (CAMs).

BACKGROUND

Coronary plaque inflammation is a key component in the pathogenesis of acute coronary syndromes. Cell adhesion molecules are critical mediators of the inflammatory process. Soluble forms of these molecules are detectable in serum and are elevated acutely in patients with UA and NQMI.

METHODS

Patients presenting with UA and NQMI had serum samples taken at presentation and then after three, six and 12 months. A control group of similar age and gender distribution was used for comparison. Levels of soluble inter-cellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial-selectin and platelet-selectin were measured using an ELISA technique.

RESULTS

We studied 91 patients (M/F = 73/18, mean age 62 +/- 11 years, 56 UA and 35 NQMI) and 24 controls (M/F = 18/6, mean age 56 +/- 12 years). Levels of all four soluble CAMs were significantly elevated in both UA and NQMI patients at presentation, three and six months in comparison with controls. Levels in UA and NQMI groups fell between six and 12 months after initial presentation.

CONCLUSIONS

The results suggest that the inflammatory stimulus triggering expression of CAMs is sustained for up to six months after presentation with either UA or NQMI and then returns toward control values over the following six months.

Correlation between monocyte and T-lymphocyte activation markers in patients with acute coronary syndrome

Evidence suggesting the involvement of activated monocytes and T-lymphocytes in the acute phase of coronary artery disease (CAD) has been increasing. But a detailed analysis of a correlation between monocyte and T-lymphocyte activation markers in CAD has not yet been done. We analyzed plasma C-reactive protein (CRP) levels and the expression levels of CD14 and CD11b on monocytes and the percentage of HLA-DR T-lymphocytes in 25 patients with acute coronary syndrome (ACS), 12 stable angina (SA) patients, and 23 control subjects using flow-cytometry. The expression of CD14 by monocytes was increased significantly in ACS patients (activation index 38.7 +/- 2.5, mean +/- SEM) in comparison to the control subjects (8.0 +/- 1.9) and the SA patients (16.9 +/- 3.9) (p < 0.001 and p < 0.01, respectively). The expression of CD11b by monocytes of ACS patients (4.6 +/- 0.6) was also increased significantly in comparison to control subjects (2.2 +/- 0.1) and the SA patients (2.2 +/- 0.3) (p < 0.001 for both). Also, a significantly higher percentage of HLA-DR positive T-lymphocytes (19.2 +/- 1.8 vs 13.5 +/- 1.2%, p < 0.05) was observed among ACS patients in comparison to control subjects. Significant increases in plasma CRP levels were also detected in ACS patients. Furthermore, there were statistically significant correlations among these activation markers. These results indicate that activation of inflammatory cells may play a role in the pathogenesis of ACS. The correlation between the activation status of monocytes and T-lymphocytes indicates that the activation of these immune cells is linked in such a way that activation of one type of cell may lead to the activation of another type of cell.

Increased expression of peripheral benzodiazepine receptors on leukocytes in silent myocardial ischemia

OBJECTIVES

The purpose of this study was to evaluate benzodiazepine receptor expression on leukocytes from patients with symptomatic or silent myocardial ischemia.

BACKGROUND

Silent myocardial ischemia is frequently observed in patients with coronary artery disease. Pain can be effectively controlled by various endogenous mechanisms. Benzodiazepines and their receptors play key roles in pain, in interactions with peptide opioids, in inflammation and in the response to stress.

METHODS

The study group consisted of 57 patients with reproducible exercise-induced myocardial ischemia. The presence of a constant behavior in the anginal pain perception during both exercise-induced ischemia and daily life was the most important inclusion criterion. Venous blood samples were taken from all patients to evaluate the expression of peripheral benzodiazepine receptors by flow cytometry. The study cohort was classified into two groups: 24 patients who had anginal pain both at home and during the exercise stress test and 33 patients who were asymptomatic during both daily life and exercise-induced ischemia.

RESULTS

Flow cytometry analysis showed increased expression of peripheral benzodiazepine receptors on all types of leukocytes in the asymptomatic patients. The difference was statistically significant for lymphocytes (p < 0.005), monocytes (p < 0.001) and granulocytes (p < 0.001).

CONCLUSIONS

These data show that expression of peripheral benzodiazepine receptors was higher in patients with silent myocardial ischemia than in symptomatic patients.

Apolipoprotein (a) fragments in relation to human carotid plaque instability

PURPOSE

An elevated plasma level of lipoprotein (a) is an independent risk factor for atherothrombotic cardiovascular disease by yet undefined mechanisms. We have previously reported that matrix metalloproteinases cleave apolipoprotein (a) into 2 main fragments, F1 and F2, the latter (the C-terminal domain) exhibiting in vitro a high-affinity binding to extracellular matrix components, including fibrin(ogen). We therefore tested the hypothesis that the lipoprotein (a) matrix metalloproteinase-derived F2 is localized in potentially or morphologically unstable human carotid plaque at regions of increased matrix metalloproteinase activity.

METHODS

Carotid plaques removed after endarterectomy (n = 18) were evaluated for structural features indicative of instability (thin fibrous cap, inflammation, and proximity of the necrotic core to the lumen); each plaque was classified as unstable (n = 10) or stable (n = 8). Western blot analysis was performed to quantitate apolipoprotein (a) and its fragments F1 and F2 in plaque extracts. Immunohistochemical staining was used to localize apolipoprotein (a) and its fragments within the atherosclerotic plaque. In situ zymography was used to determine regions of gelatinase (matrix metalloproteinase 2 and matrix metalloproteinase 9) activity.

RESULTS

Western blot analyses demonstrated a 2.5-fold higher density of F2 in unstable plaques than in stable plaques (3.07 +/- 1.9 vs 1.18 +/- 0.8; P <.05). In morphologically unstable plaques, there was preferential distribution of F2 within regions of fibrous cap inflammation and/or foam cell accumulation and within abluminal necrotic cores. In morphologically stable plaques, however, localization was predominantly found in the medial smooth muscle cells. Regions of enhanced matrix metalloproteinase 2 and matrix metalloproteinase 9 activity co-localized with the transmural distribution of F2 within the plaque.

CONCLUSIONS

These findings suggest that F2 in regions of increased matrix metalloproteinase activity is a potential mechanism for superimposed thrombotic events in morphologically unstable human carotid plaques. The relationship between plasma lipoprotein (a) levels and accumulation of F2 and the potential correlation of F2 to human plaque disruption and thrombosis warrant further study.

Circulating levels of IL-1beta, a prothrombotic cytokine, are elevated in unstable angina versus stable angina

BACKGROUND

Multiple studies support a role for inflammation in the pathogenesis of coronary atherosclerosis and unstable cardiac syndromes. However, of the known proinflammatory cytokines, only elevated plasma levels of interleukin-6 have been linked to unstable angina. We sought to examine the plasma levels of other major proinflammatory cytokines in similar clinical settings and to determine the extent of the relationship between inflammation and unstable coronary syndromes by measuring the levels of various proinflammatory cytokines in patients with stable and unstable angina.

METHODS

We measured plasma levels of interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6) in 97 patients: 67 with stable angina, 24 with unstable angina, and 15 healthy controls.

RESULTS

Mean levels of IL-1beta were significantly higher in patients with unstable angina as compared to patients with stable angina (p =.009). Levels of IL-6 were significantly higher than control patients for both stable angina and unstable angina patients (p =.031 and.006, respectively). No significant differences were found in the levels of TNF-alpha.

CONCLUSIONS

Our results suggest that both IL-1beta and IL-6 contribute to the pathogenesis of unstable angina, and that the profile of circulating plasma levels of proinflammatory cytokines differs in unstable angina from that in stable angina. Abbreviated Abstract. Multiple studies support a role for inflammation in the pathogenesis of coronary atherosclerosis and unstable cardiac syndromes. We measured plasma levels of interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6) in patients with stable and unstable coronary syndromes. Levels of IL-1beta and IL-6 were found to be elevated in patients with unstable coronary syndromes. No significant differences were found in the levels of TNF-alpha. Our results suggest that both IL-1beta and IL-6 contribute to the pathogenesis of unstable angina.

Elevated levels of soluble intercellular adhesion molecule-1 in the coronary circulation of patients with coronary organic stenosis and spasm

The cell surface expression of intercellular adhesion molecule-1 (ICAM-1) is upregulated following activation during inflammatory responses, mediating both cell migration and activation. The involvement of inflammation in unstable angina is suggested by the presence of activated circulating leukocytes. To examine whether plasma soluble ICAM-1 (sICAM-1) levels increase in the coronary circulation of patients with coronary organic stenosis and coronary spasm, plasma sICAM-1 levels were measured in the coronary sinus (CS) and the aortic root (Ao) simultaneously in 10 patients with 90% or more coronary narrowing and coronary spasm (coronary spastic angina (CSA) with organic stenosis), in 11 patients with coronary spasm and no significant coronary narrowing (CSA without organic stenosis), in 16 patients with stable exertional angina, and in 13 control subjects. The plasma sICAM-1 levels (ng/ml) in the CS increased in CSA with organic stenosis (230+/-26) as compared with CSA without organic stenosis (158+/-14), stable exertional angina (130+/-9) and control subjects (121+/-10) (p<0.01). The levels in the Ao also increased in CSA with organic stenosis (208+/-24) as compared with CSA without organic stenosis (149+/-13), stable exertional angina (130+/-11) and control subjects (121+/-10) (p<0.01). Furthermore, the plasma sICAM-1 levels were higher in the CS than in the Ao only in CSA with organic stenosis. These results suggest that activation of leukocytes occurs through the induction of ICAM-1 in the coronary circulation in the patients with CSA with organic stenosis.

Heat production of atherosclerotic plaques and inflammation assessed by the acute phase proteins in acute coronary syndromes

Several studies have shown that inflammation plays an important role in the pathogenesis of coronary heart disease (CHD). Serum amyloid A (SAA) and C-reactive protein (CRP) reactants of the acute phase of inflammation, have been shown to be increased in patients with CHD. Recently ex vivo studies demonstrated that some types of atherosclerotic plaques show substantially warmer regions. A catheter-based technique has been developed to measure the temperature of human arteries in vivo. Therefore, the aim of the present study was to measure the luminal surface temperature in patients with CHD and to correlate it with the acute phase proteins in order to discriminate the role of inflammation in heat production in acute coronary syndromes. Sixty patients were studied with CHD (20 with stable angina, 20 with unstable angina and 20 with acute myocardial infarction) and 20 sex- and age-matched controls without coronary artery disease, by measuring plasma levels of SAA, CRP, plasma lipids and intracoronary arterial luminal wall temperature. Intracoronary temperature was measured with a thermography catheter developed in our Institution: a thermistor probe with a temperature accuracy of 0.05 degrees C, was attached at the distal end of a long 3F polyurethane shaft. It was found that the median temperature differences at the site of the lesion from the core temperature was increased in patients with unstable angina (1.025 degrees C) and acute myocardial infarction (2.150 degrees C) compared with stable angina (0.300 degrees C), P<0.001 for each comparison. Furthermore, stable angina has increased temperature differences compared with controls (0.200 degrees C, P<0.001). There were very good correlations between CRP and SAA with the temperature (r=0.796, P=0.01 and r=0.848, P=0.01, respectively). Local heat at the site of lesion is increased in patients with acute coronary syndromes and may arise from an aggressive inflammatory response occurring in these situations. The sensitive measurement of plaque temperature as a prognostic marker may be useful in the management of coronary heart disease.

Novel Antithrombotic Strategies for the Treatment of Coronary Artery Thrombosis: A Critical Appraisal

Large-scale clinical trials have demonstrated that treatment of patients with acute myocardial infarction and unstable angina with antithrombotic agents significantly improves outcome. Despite the proven benefit of current therapies, there is a widespread perception that outcome could be enhanced further with novel antithrombotic agents. Enthusiasm for novel antithrombotic strategies has been stimulated by recent advances in the understanding of the mechanisms responsible for coronary artery thrombosis, which has led to the development of diverse inhibitors of platelet function and coagulation factors. In experimental models of coronary artery thrombosis, aspirin and heparin have been ineffective in preventing recurrent thrombosis after coronary thrombolysis and in preventing the progression of thrombosis in response to strong thrombogenic stimuli. In contrast, inhibitors of the platelet fibrinogen receptor, direct-acting thrombin inhibitors, and inhibitors of coagulation factors that promote elaboration of thrombin have been shown to be effective in attenuating arterial thrombosis in a variety of experimental preparations. Initial clinical trials with these agents have also documented efficacy in attenuating thrombotic events in patients treated with coronary thrombolysis and in those with unstable angina. However, optimal doses of novel antithrombotic agents, the degree to which combination antiplatelet and anticoagulant therapies are needed, and the risk/benefit ratio associated with specific novel antithrombotic drugs are still relatively undefined. With regard to the latter, it is possible that the large-scale clinical trials now in progress may show an increase in bleeding complications with novel anticoagulants compared with conventional therapy. Nonetheless, there are considerable data that suggest that treatment with aspirin and heparin is not completely effective in preventing the progression of thrombosis or its recurrence after interventions in high-risk subgroups of patients with coronary artery thrombosis and unstable coronary artery disease. Accordingly, continued investigation of a large variety of antithrombotic agents, both currently available and in development, should improve the treatment of high-risk patients with coronary disease if regimens with appropriate efficacy but without serious hemorrhagic effects can be designed.

Enhanced inflammatory response in patients with preinfarction unstable angina

OBJECTIVES

We assessed the extent and the time course of the acute phase response following myocardial cell necrosis and its relationship with the presence of preinfarction unstable angina (UA).

BACKGROUND

Elevated levels of acute phase proteins have been reported in patients with UA and in patients with acute myocardial infarction (MI).

METHODS

C-Reactive Protein (CRP), serum amyloid A protein (SAA) and interleukin-6 (IL-6) were measured in 36 patients with MI admitted within 3 h from symptoms onset. All patients had normal levels of creatine kinase and of troponin T on admission, rising above diagnostic levels within 6 to 12 h. Blood samples for CRP, SAA and IL-6 measurements were taken on admission, at 6, 24, 48, 72 h and at discharge.

RESULTS

Twenty of the 36 patients studied presented an unheralded MI (Group 1); the remaining 16 patients had symptoms of unstable angina in the preceding 7 days (Group 2). Group 2 patients have much higher levels of CRP and SAA on admission (median values 8.8 vs. 3 mg/L and 28 vs. 3.4 mg/L, respectively, all p<0.001). Following the necrotic insult, despite similar infarct size and clinical signs of reperfusion, Group 2 patients had strikingly higher peaks of IL-6 (median values 85.2 vs. 19 pg/ml, p<0.05), CRP (50 vs. 31.4 mg/L, p<0.05) and SAA (228 vs. 45 mg/L, p<0.001).

CONCLUSIONS

Our data demonstrated that the acute phase response is greatly enhanced in patients with preinfarction UA compared with those presenting with an unheralded MI. The significant differences in acute phase response observed in these two clinical presentations of MI indicate a major difference in their underlying pathogenetic components.

Independent prognostic value of elevated C-reactive protein in unstable angina

BACKGROUND

There is growing evidence of the prognostic importance of C-reactive protein (CRP) in unstable angina. However, the independent value of CRP relative to other conventional markers at different stages of treatment has not been established. Therefore, we assessed the in-hospital and 90-day prognostic values of serum CRP in unstable angina. We also compared the relation of CRP at admission and discharge with 90-day outcome.

METHODS AND RESULTS

One hundred ninety-four consecutive patients were included in a derivation (n = 105) and a validation set (n = 89). Serum CRP was measured at admission, at 48 hours, and at hospital discharge. A cutoff point of 1.5 mg/dL for CRP provided optimum sensitivity and specificity for adverse outcome, based on the receiver operator curves. No association was found between CRP on admission and in-hospital outcome. CRP at admission, adjusted for age, ECG findings on admission, silent ischemia, left ventricular wall motion score, and high-risk clinical presentation, was related to the combined end point of refractory angina, myocardial infarction, or death at 90 days (hazard ratio [HR] 1.9, 95% CI 1.2 to 8.3, P = 0.002). CRP at hospital discharge was the strongest independent marker of an adverse outcome (HR 3.16, 95% CI 2.0 to 5.2, P = 0.0001). These results were confirmed in the validation set (CRP at discharge: HR 3. 3, 95% CI 2.0 to 7.69, P = 0.0001).

CONCLUSIONS

In unstable angina, CRP is a strong independent marker of increased 90-day risk. Compared with CRP at admission, CRP at discharge is better related to later outcome and could be of great utility for risk stratification.

Increased expression of the CD11b/CD18 antigen on the surface of peripheral white blood cells in patients with ischemic heart disease: further evidence for smoldering inflammation in patients with atherosclerosis

BACKGROUND

This study examined the availability of the CD11b/CD18 and CD62L antigens on the surface of peripheral blood leukocytes in patients with ischemic heart disease.

METHODS AND RESULTS

The study population included 45 patients with angiographically documented ischemic heart disease admitted to our department of internal medicine and the cardiology department during 1 month (December 1997). Sixty-six healthy members of the hospital medical staff served as control subjects. Another 39 post-trauma patients who were admitted to the emergency room were also evaluated. Patients with ischemic heart disease had significantly (P <.002) higher concentrations of CD11b/CD18 antigen on the surface of their polymorphonuclear leukocytes and monocytes (mean fluorescence intensity of 203 +/- 81 and 261 +/- 75, respectively) compared with the control group (mean fluorescence intensity 158 +/- 68 and 211 +/- 74, respectively) and to the group of patients with acute stress (mean fluorescence intensity of 146 +/- 70 and 200 +/- 22, respectively).

CONCLUSIONS

The presence of increased concentration of CD11b/CD18 suggests that circulating leukocytes are activated in patients with ischemic heart disease. This activation probably reflects the presence of an inflammatory response involving the atherosclerotic lesion and is not merely a result of acute stress.

Increased release of the soluble form of the adhesion molecules L-selectin and ICAM-1 but not E-selectin during attacks of angina pectoris

Myocardial ischemia leads to the activation of neutrophils as well as endothelial cells. The interaction between these cells is dependent on certain adhesion glycoproteins which are expressed on their surface. Adhesion of neutrophils to endothelium, mediated by adhesion molecules, has been shown to result in coronary capillary plugging and impairment of coronary blood flow. In certain conditions, upon cell activation, adhesion proteins may be released in soluble form into the circulating blood. The purpose of our study was to verify whether myocardial ischemia occurring during angina episodes results in the release of the soluble adhesion molecules, L-selectin, E-selectin, and intracellular adhesion molecule-1 (ICAM-1), into the circulation. Plasma samples were collected by venepuncture from 15 patients admitted to the emergency room with chest pain caused by attacks of angina pectoris and 15 patients with noncardiac chest pain. To confirm the diagnosis, all patients underwent an exercise stress test and, if not conclusive, 99mTc MIBI SPECT or coronary arteriography. Another set of plasma samples were taken from each patient in the absence of chest pain. In addition, blood for analysis was obtained from 15 sex-and age-matched healthy subjects. Soluble adhesion molecules plasma levels were measured by standard enzyme-linked immunosorbent assay. In patients with angina pectoris, plasma levels of soluble L-selectin estimated during chest pain were significantly higher than in the control group and decreased in the absence of chest pain. Similarly, the mean concentration of soluble ICAM-1 at the time of angina onset was significantly elevated in the patients in comparison with the control group and remained higher, although not significantly, in the absence of chest pain. In patients with noncardiac chest pain, plasma levels of soluble L-selectin did not differ significantly from those observed in control subjects. In this group of patients, the plasma levels of soluble ICAM-1 estimated during pain onset and in the absence of this symptom were not significantly elevated. On the contrary, the mean values of soluble E-selectin in the patients with ischemic cardiac pain during chest pain and in the absence of this symptom, as well as those in the patients with noncardiac chest pain during or without symptoms, remained unchanged in comparison with the control group. During attacks of angina pectoris an increase in the plasma levels of the soluble adhesion molecules, ICAM-1 and L-selectin, was noted, possibly reflecting activation of neutrophils and endothelial cells during myocardial ischemia. However, E-selectin plasma levels remained unchanged in response to myocardial ischemia.

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.

From plaque biology to clinical setting

Coronary atherosclerosis may cause acute and chronic ischemic syndromes; the former are caused by "acute plaque events," mostly thrombosis complicating vulnerable ruptured plaques, namely severe lesions with large core, thin cap, and weak shoulder infiltrated by activated inflammatory cells. Plaque rupture may also occur in nonischemic settings and is not obligatorily complicated by thrombosis. Furthermore, plaque rupture is not the only thrombus substrate in acute ischemic syndromes: Superficial erosion of fibrous plaques is found in 44% of acute thrombi in sudden coronary deaths and in 25% of those in acute myocardial infarctions. Coronary thrombosis appears to be triggered by superficial intimal inflammation in plaque ulceration and by neointimal hyperplasia in plaque erosion. "Endogenous" and, recently, exogenous factors, particularly infective intracellular organisms, have been proposed as major contributors to plaque inflammation, activation, and vulnerability. Possible exogenous triggers are DNA and RNA viruses and intracellular bacteria such as Chlamydia pneumoniae, which has been identified with microbiological, ultrastructural, immunohistochemical, and molecular tools in a consistent proportion of human plaque samples. Chlamydia increases local thrombogenicity and is associated with an atherogenic lipid profile. Systemic indexes of inflammation, such as PCR, SAA, and fibrinogen, are also increased in acute syndromes and common infectious diseases with high morbidity and minimal clinical impact are good candidates; Helicobacter pylori is a major one. Infectious agents could link local and systemic inflammation: White cells infected in its target tissue could circulate into the flow and be captured, on a specific local trigger, into vessel walls thus stimulating local inflammation.

Inflammation, the acute phase response and atherosclerosis

There is increasing evidence that atherosclerosis is a chronic inflammatory disorder resulting from a combination of processes, and that acute exacerbations of this inflammation are associated with the acute coronary syndromes such as myocardial infarction and unstable angina. Measurement of the serum level of acute phase proteins, such as C-reactive protein and serum amyloid A protein, has been used to predict the risk of acute events in patients with atherosclerosis. Prospective studies have shown that higher serum acute phase protein levels, often within the reference range, are associated with increased risk of myocardial infarction (MI), stroke or peripheral vascular disease and predict risk of infarction and death among high-risk patients. These observations have important implications for the assessment of patients and for treatment.

Aggressive versus conservative therapy in unstable angina

In patients with unstable angina, non-Q-wave, and Q-wave myocardial infarction, atherosclerotic plaque rupture leads to a variable amount of platelet adhesion and aggregation, vasoconstriction, and partially or totally occlusive thrombus formation. This article focuses on the role of aggressive (routine angiography and revascularization) versus conservative (maximal medical therapy, with catheterization and revascularization reserved for those with spontaneous or provable ischemia) management of the patient with unstable angina.

Early temporal expression of soluble cellular adhesion molecules in patients with unstable angina and subendocardial myocardial infarction

Inflammation is increasingly considered to be involved in the pathogenesis of acute coronary syndromes. We documented persistent elevation in the levels of soluble ICAM-1 and soluble VCAM-1 and a decrease in the levels of soluble E-selectin in the first 72 hours of acute presentation in patients with unstable angina and subendocardial myocardial infarction.

Urokinase plasminogen activator system in humans with stable coronary artery disease

1. The present study compares plasma urokinase plasminogen activator (uPA) peptide levels, plasma plasminogen inhibitor (PAI-1) activity and urokinase receptors (uPAR) on peripheral blood monocytes of patients with stable coronary artery disease (SCAD) and healthy volunteers. 2. Urokinase plasminogen activator levels were analysed by ELISA and PAI-1 activity was determined by a plasmin generation method using the chromogenic substrate S2390. Relative uPAR numbers and the adhesion molecules CD11b/CD18 on peripheral blood monocytes were estimated using specific antibodies and flow cytometry. 3. Patients with SCAD were found to have higher plasma uPA peptide levels than age-matched healthy subjects (10.40 +/- 0.99 vs 8.25 +/- 0.53 pmol/L, respectively; P < 0.05). 4. Plasma PAI-1 activity was also higher in patients with SCAD than in healthy subjects (13.6 +/- 2.5 vs 5.2 +/- 1.0 IU/mL, respectively; P < 0.05). 5. Relative uPAR and CD11b/CD18 adhesion molecules were similar on peripheral blood monocytes of patients with SCAD and in healthy subjects. 6. The data indicate a pattern of expression/activity of uPA and PAI-1 in patients with SCAD suggestive of an impaired fibrinolytic ability.