Monocyte-related cytokines in acute myocardial infarction

Association of plasma macrophage colony-stimulating factor with cardiovascular morbidity and all-cause mortality in chronic hemodialysis patients

Background

Cardiovascular disease (CVD) events are the main cause of death in long-term hemodialysis (HD) patients. Macrophage colony- stimulating factor (M-CSF) is actively involved in the formation of atherosclerosis and causes plaque instability, thrombosis and the development of acute coronary syndromes. However, little information is available on the role of M-CSF in HD patients. We aimed to investigate the association between plasma M-CSF levels and CVD events as well as all-cause mortality in patients undergoing long-term HD.

Methods

Fifty two HD patients and 8 healthy controls were recruited in this study. HD patients were followed up from September 2014 to May 2017. The primary end point was CVD event, the secondary outcome was death from any cause. Patients were divided into two groups with low and high M-CSF levels based on the optimal cut-off value determined by the ROC curve. Cox regression analyses were used to assess the predictive value of plasma M-CSF for CVD events and all-cause mortality in HD patients. We tested the levels of plasma M-CSF and other inflammatory cytokines in surviving HD patients using ELISA or CBA kit.

Results

The average plasma level of M-CSF in 52 patients was approximately twice that of healthy controls (992.4 vs. 427.2 pg/mL; p <  0.05). During 32 months of follow-up, 26 patients (50.0%) had at least one CVD event and 8 patients (15.4%) died. The mean plasma M-CSF concentration increased in survivors after follow-up compared to that detected at baseline (1277.8 ± 693.3 vs. 997.2 ± 417.4 pg/mL; p <  0.05). Multivariate Cox regression analysis showed that plasma M-CSF is an independent risk factor for CVD events in HD patients (p <  0.05). In the Cox regression model after adjusting for gender and age, high M-CSF levels were related to an increased risk of all-cause death (p <  0.05). We also found that M-CSF levels were positively correlated with IL-6 and IL-18 levels (both p < 0.05), which are the major pathogentic cytokines that contribute to HD-related CVD events.

Conclusion

M-CSF is a prognostic factor for CVD events and all-cause mortality in HD patients.

Role of Novel Biomarkers of Inflammation in Patients With Stable Coronary Heart Disease

Atherosclerosis is a dynamic chronic inflammatory process, and some inflammatory biomarkers have roles in this process. The levels of C-reactive protein (CRP) in patients with chronic stable coronary heart disease (CHD) have not been investigated well, and the levels of macrophage colony-stimulating factor (M-CSF) and interleukin-3 (IL-3) in patients with chronic stable CHD and the effects of these cytokines on atherogenesis are not known. To determine whether new inflammatory biomarkers have roles in atherosclerosis, the authors measured the levels of CRP, M-CSF, and IL-3 in patients with chronic stable CHD and in healthy controls. They measured plasma CRP concentrations by using a highly sensitive CRP reagent with immunonephelometric method, and plasma M-CSF and IL-3 concentrations with the help of a commercial enzyme-linked immunoassay test in 31 patients with chronic stable CHD documented by coronary angiography and in 22 age-matched healthy control subjects documented by coronary angiography. Mean plasma CRP, M-CSF, and IL-3 concentrations in patients with chronic stable CHD were significantly higher than those in controls (8.2 vs 4.6 mg/L, 195.3 vs 28.9 pg/mL, 173 vs 118 ng/mL, respectively, pπ.05). CRP, M-CSF, and IL-3 were all increased in patients with chronic stable CHD relative to controls. These findings suggest that these are new inflammatory biomarkers that may have important roles in the development of atherosclerotic lesions.

Relationship between site of myocardial infarction, left ventricular function and cytokine levels in patients undergoing coronary artery surgery

BACKGROUND

The purpose of this study was to examine the relationship between left ventricular (LV) function, cytokine levels and site of myocardial infarction (MI) in patients undergoing coronary artery bypass grafting (CABG).

METHODS

Sixty patients undergoing CABG were divided into three groups (n = 20) according to their history of site of myocardial infarction (MI): no previous MI, anterior MI and posterior/inferior MI. In the pre-operative period, detailed analysis of LV function was done by transthoracic echocardiography. The levels of adrenomedullin, interleukin-1-beta, interleukin-6, tumour necrosis factor-alpha (TNF-α) and angiotensin-II in both peripheral blood samples and pericardial fluid were also measured.

RESULTS

Echocardiographic analyses showed that the anterior MI group had significantly worse LV function than both the group with no previous MI and the posterior/inferior MI group (p < 0.05 for LV end-systolic diameter, fractional shortening, LV end-systolic volume, LV end-systolic volume index and ejection fraction). In the anterior MI group, both plasma and pericardial fluid levels of adrenomedullin and and pericardial fluid levels of interleukin-6 and interleukin- 1-beta were significantly higher than those in the group with no previous MI (p < 0.05), and pericardial fluid levels of adrenomedullin, interleukin-6 and interleukin-1-beta were significantly higher than those in the posterior/inferior MI group (p < 0.05).

CONCLUSIONS

The results of this study indicate that (1) patients with an anterior MI had worse LV function than patients with no previous MI and those with a posterior/inferior MI, and (2) cytokine levels in the plasma and pericardial fluid in patients with anterior MI were increased compared to patients with no previous MI.

Acute gouty arthritis complicated with acute ST elevation myocardial infarction is independently associated with short- and long-term adverse non-fatal cardiac events

Large epidemiologic studies have associated gouty arthritis with the risk of coronary heart disease. However, there has been a lack of information regarding the outcomes for patients who have gout attacks during hospitalization for acute myocardial infarction. We reviewed the data of 444 consecutive patients who were admitted to our hospital between 2005 and 2008 due to acute ST elevation myocardial infarction (STEMI). The clinical outcomes were compared between patients with gout attack and those without. Of the 444, 48 patients with acute STEMI developed acute gouty arthritis during hospitalization. The multivariate analysis identified prior history of gout and estimated glomerular filtration rate as independent risk factors of gout attack for patients with acute STEMI (odds ratio (OR) 21.02, 95 % CI 2.96-149.26, p = 0.002; OR 0.92, 95 % CI 0.86-0.99, p = 0.035, respectively). The in-hospital mortality and duration of hospital stay did not differ significantly between the gouty group and the non-gouty group (controls). During a mean follow-up of 49 ± 28 months, all-cause mortality and stroke were similar for both groups. Multivariate Cox regression showed that gout attack was independently associated with short- and long-term adverse non-fatal cardiac events (hazard ratio (HR) 1.88, 95 % CI 1.09-3.24, p = 0.024; HR 1.82, 95 % CI 1.09-3.03, p = 0.022, respectively). Gout attack among patients hospitalized due to acute STEMI was independently associated with short-term and long-term rates of adverse non-fatal cardiac events.

GM-CSF promotes inflammatory dendritic cell formation but does not contribute to disease progression in experimental autoimmune myocarditis

BACKGROUND

Granulocyte macrophage-colony stimulating factor (GM-CSF) is critically required for the induction of experimental autoimmune myocarditis (EAM), a model of post-inflammatory dilated cardiomyopathy. Its specific role in the progression of myocarditis into end stage heart failure is not known.

METHODS AND RESULTS

BALB/c mice were immunized with myosin peptide and complete Freund's adjuvant at days 0 and 7. Heart-infiltrating inflammatory CD133(+) progenitors were isolated from inflamed hearts at the peak of inflammation (day 21). In the presence of GM-CSF, inflammatory CD133(+) progenitors up-regulated integrin, alpha X (CD11c), class II major histocompatibility complex, CD80 and CD86 co-stimulatory molecules reflecting an inflammatory dendritic cell (DC) phenotype. Inflammatory DCs stimulated antigen-specific CD4(+) T cell proliferation and induced myocarditis after myosin peptide loading and adoptive transfer in healthy mice. Moreover, GM-CSF treatment of mice after the peak of disease, between days 21 and 29 of EAM, transiently increased accumulation of inflammatory DCs in the myocardium. Importantly, bone marrow-derived CD11b(+) monocytes, rather than inflammatory CD133(+) progenitors represent the dominant cellular source of heart-infiltrating inflammatory DCs in EAM. In contrast, GM-CSF treatment neither affected numbers of heart-infiltrating CD45(+) and CD3(+) T cells nor the development of post-inflammatory fibrosis.

CONCLUSIONS

GM-CSF treatment promotes formation of inflammatory DCs in EAM. In contrast to the active roles of GM-CSF and DCs in EAM induction, GM-CSF-induced inflammatory DCs neither prevent resolution of active inflammation, nor contribute to post-inflammatory cardiac remodelling. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.

Elevated peripheral blood mononuclear cell count is an independent predictor of left ventricular remodeling in patients with acute myocardial infarction

OBJECTIVES

Peripheral blood mononuclear cells (PBMCs) increase after acute myocardial infarction (AMI) and infiltrate to the infarct region. However, its impact on left ventricular (LV) remodeling remains unclear. The purpose of the present study was to clarify whether elevated PBMC count contributed to LV remodeling in patients with AMI.

SUBJECTS AND METHODS

A total of 131 patients with AMI were recruited. White blood cell (WBC), monocyte, and lymphocyte counts were measured at presentation and every 24h for five days after presentation. The correlation between PBMC count and LV remodeling was evaluated. LV remodeling was defined as an increase of LV end-diastolic volume index ≥ 10% at the 6-month follow-up left ventriculography.

RESULTS

Forty-eight patients had LV remodeling. Peak WBC (p=0.008), peak monocyte (p=0.001), and peak PBMC (p<0.001) counts were significantly greater in patients with LV remodeling than those without remodeling. Multivariate analysis revealed the peak PBMC count ≥ 3600/mm(3) was an independent predictor of LV remodeling [relative risk (RR) 3.243, p=0.011].

CONCLUSION

Increased PBMC count is significantly correlated with LV remodeling, thus suggesting that PBMCs play a pivotal role for the development of LV remodeling after AMI.

Association between circulating monocytes and coronary plaque progression in patients with acute myocardial infarction

BACKGROUND

Monocytes and macrophages have been shown to play major roles in the progression of atherosclerosis. This study examined whether the circulating monocyte count can be used to predict coronary plaque progression of non-culprit intermediate lesions in acute myocardial infarction (AMI).

METHODS AND RESULTS

Intravascular ultrasound findings of non-culprit intermediate plaque in 90 patients were analyzed in the acute phase and at a 7-month follow up. A higher peak monocyte count after AMI was associated with a greater plaque volume change (r=0.32, P=0.002). Multivariate analysis showed that a peak monocyte count of > or =800 /mm(3) was an independent predictor of plaque progression (odds ratio 5.02, P=0.005). High monocyte (> or =800 /mm(3)) at baseline had a higher monocyte count at 7-month follow up than did those with a lower count (368+/-109 vs 263+/-64 /mm(3), P<0.0001). Moreover, the monocyte count at the 7-month follow up was also associated with plaque volume change (r=0.29, P=0.006).

CONCLUSIONS

The results suggest that circulating monocytes play an important role in the progression of coronary plaque in AMI and that the peak monocyte count during hospitalization might be a predictor of plaque progression.

Significance of white blood cell count and its subtypes in patients with acute coronary syndrome

BACKGROUND

Inflammation plays a role in the pathogenesis of coronary atherosclerosis.

MATERIALS AND METHODS

Six hundred twenty-three patients with acute coronary syndrome (ACS) referred for coronary angiography for the first time in our hospital were enrolled in this study. White blood cell and its subtypes were measured on admission. The study population was divided into three groups based on total white blood cell count and followed up. Clinical end points were major adverse cardiac events (MACEs), including cardiogenic death, stroke, heart failure, non-fatal myocardial infarction, rehospitalization for angina pectoris.

RESULTS

The median age was 68 years (range 31-92) and 64.2% of the patients were men. The median white blood cell count was 6.48 x 10(9 )L(-1) (range 2.34-27.10 x 10(9 )L(-1)). The median follow-up duration was 21 months (range 1-116) and MACEs occurred in 167 patients. The multivariable Cox proportional hazards regression model revealed that neutrophil count [Relative risk = 1.098, 95% Confidence interval (CI): 1.010-1.193, P = 0.029) was a risk factor for MACEs. The logistic regression model revealed that lymphocyte count [Odds ratio (OR) = 1.075, 95% CI: 1.012-1.142, P = 0.018] and monocyte count (OR = 8.578, 95% CI: 2.687-27.381, P < 0.001) were predictive of stenosis >or= 75%; Neutrophil proportion (OR = 1.060, 95% CI: 1.007-1.115, P = 0.026), monocyte count (OR = 12.370, 95% CI: 1.298-118.761, P = 0.029) were predictive of the presence of multivessel disease. Kaplan-Meier analysis of short-term and long-term cumulative survival showed no significant statistical differences among three groups.

CONCLUSIONS

Neutrophil count adds prognostic information to MACEs in ACS. Monocyte count and lymphocyte count are predictive of severity of coronary atherosclerosis.

Immune modulation: role of the inflammatory cytokine cascade in the failing human heart

Recent studies have determined that expression of inflammatory mediators, such as cytokines and chemokines, is an important factor in the development and progression of heart failure (HF). These inflammatory mediators are expressed in response to various myocardial insults, including myocardial ischemia, viral infection, and toxins, and appear to have a detrimental effect on cardiac function and prognosis in HF patients. Our previous reports have shown activation of inflammatory cytokines, particularly tumor necrosis factor-alpha (TNF-alpha), in the myocardium and peripheral monocytes in patients with HF. Indeed, sustained increases in cytokines, including TNF-alpha and its receptor, lead to monocyte phenotype transition, myocytic apoptosis, and activation of matrix metalloproteinase. This in turn modifies the interstitial matrix, augmenting further ventricular remodeling. Thus, in view of the emerging importance of TNF-alpha in the pathogenesis of HF, we review the effects of TNF-alpha on the physiology of the heart and the development of clinical strategies to target the inflammatory cytokine cascade.

Prognostic value of C-reactive protein, fibrinogen, interleukin-6, and macrophage colony stimulating factor in severe unstable angina

BACKGROUND

Inflammatory process plays an important role in the pathogenesis of acute coronary syndromes.

HYPOTHESIS

The study was undertaken to evaluate whether admission levels of C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6). and macrophage colony stimulating factor (MCSF) can predict short-term prognosis in patients with unstable angina.

METHODS

C-reactive protein, fibrinogen, IL-6, and MCSF were measured on admission in 141 consecutive patients, aged 59 +/- 10 years, with unstable angina (Braunwald class IIIb). Patients were divided into two groups according to their in-hospital outcome: Group 1 comprised 77 patients with a complicated course (2 died, 15 developed nonfatal myocardial infarction, and 60 had recurrence of angina), and Group 2 comprised 64 patients with an uneventful course.

RESULTS

Admission median levels of CRP (8.8 vs. 3.1 mg/l, p = 0.0002). fibrinogen (392 vs. 340 mg/dl, p = 0.008), IL-6 (8.8 vs. 4.5 pg/ml, p = 0.03), and MCSF (434 vs. 307 pg/ml, p = 0.0001) were higher in Group I than in Group 2. The MCSF levels were an independent risk factor for in-hospital events, with an adjusted odds ratio for eventful in-hospital outcome of 3.3 (95% confidence interval 1-10.9, p = 0.04), and correlated with levels of IL-6 (r(s) = 0.52, p = 0.0001), CRP (r(s) = 0.43, p = 0.0001), and fibrinogen (r(s) = 0.25, p = 0.004).

CONCLUSIONS

These findings suggest that among the studied inflammatory indices only increased admission levels of MCSF are strongly and independently related with adverse short-term prognosis in patients with severe unstable angina.

Role of novel mediators of inflammation in left ventricular remodeling in patients with acute myocardial infarction: do they affect the outcome of patients?

Left ventricular (LV) remodeling after acute myocardial infarction (AMI) is a major mechanism for cardiovascular death and disability. A significant number of post-MI patients develop progressive left ventricular enlargement and heart failure and many require heart transplantation and ventricular assist devices. Understanding of the basic mechanisms regulating the reaction to injury is crucial for the development of site-specific cell biological strategies of intervention to both reduce injury and promote repair. To determine whether there are new inflammatory markers having a role in structural remodeling after AMI in patients who applied to the emergency department of this hospital with severe chest pain at the first 12 hours, the authors measured the levels of C-reactive protein (CRP), macrophage colony-stimulating factor (M-CSF) and interleukin-3 (IL-3) in patients with AMI at hospital admission and on day 5. They measured plasma CRP concentrations by using highly sensitive CRP reagent with the immunonephelometric method, and plasma M-CSF and IL-3 concentrations with the help of a commercial enzyme-linked immunoassay test in 30 patients with AMI. Mean plasma CRP, M-CSF, and IL-3 concentrations at admission to the hospital were significantly higher than those on day 5 (5.0 -/+ 3.1 mg/dL, 119.4 -/+ 103.6 pg/mL, and 155.1 -/+ 83.4 ng/mL, respectively, p < 0.001 for each value). CRP, M-CSF, and IL-3 were all increased in patients with AMI. These findings suggest that these are new inflammatory markers, which may have important roles in LV remodeling after AMI.

Relationship Between Peripheral Monocytosis and Nonrecovery of Left Ventricular Function in Patients With Left Ventricular Dysfunction Complicated With Acute Myocardial Infarction

BACKGROUND

Although ischemic heart failure is a major cause of mortality after acute myocardial infarction (AMI), the factors that may influence the nonrecovery of left ventricular function (LVF) after an AMI are still unclear. The aim of this study was to identify predictors of nonrecovery of LVF in patients with left ventricular (LV) dysfunction (defined as an echocardiographic ejection fraction (EF)<40%) complicated with AMI who undergo successful primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

LVF recovery was defined as improvement of LVEF more than 10% compared with baseline LVEF at follow-up. One hundred and eight patients with LV dysfunction after AMI were divided into 2 groups according to the LVF recovery at follow-up: patients with LVF recovery (n=64) vs patients without LVF recovery (n=44). The follow-up LVEF was measured at 8+/-4 months after PCI. Patients without LVF recovery were older (76+/-13 years vs 59+/-14 years, p=0.023) and the baseline peak monocyte count, creatine kinase, and troponin I levels were significantly higher in patients without LVF recovery than in patients with LVF recovery. Delta LVEF (follow-up LVEF-baseline LVEF) correlated with baseline peak monocyte count (r=-0.417, p<0.001), baseline peak creatine kinase (r=-0.269, p=0.005), and baseline peak troponin I levels (r=-0.256, p=0.007). Multivariate analyses showed that baseline peak monocyte count and old age were the independent predictors of nonrecovery of LVF (hazard ratio; 3.38, 95% confidence interval (CI): 1.16-5.43, p=0.012, and hazard ratio; 2.38, 95% CI: 1.09-4.87, p=0.025, respectively).

CONCLUSION

Peripheral monocytosis is associated with nonrecovery of LVF in patients with LV dysfunction complicating an AMI who underwent successful primary PCI. These results suggest an important role of monocytes in the expansion of the infarct and the development of chronic ischemic heart failure after reperfusion therapy.

Elevated circulating levels of heat shock protein 70 are related to systemic inflammatory reaction through monocyte Toll signal in patients with heart failure after acute myocardial infarction

BACKGROUND

Recent studies have shown that heat shock protein (HSP) 70 may serve as a "damage signal" to the immune system and could be the endogenous ligand for Toll-like receptor (TLR) 4 mediating synthesis of inflammatory cytokines.

AIMS

To explore the relationship between circulating HSP70 levels and activation of monocyte TLR4 and myocardial damage after AMI.

METHODS AND RESULTS

This study examined circulating HSP70 and monocyte TLR4 levels in 52 patients with AMI and 20 controls, and analyzed ex vivo inflammatory cytokine productions using HSP70-stimulated monocytes. Circulating HSP70 levels were higher in AMI patients on day 1 after onset than in controls and remained elevated in AMI patients 14 days after onset. HSP70 levels were positively correlated with monocyte TLR4, plasma interleukin-6 and tumor necrosis factor-alpha levels in AMI patients. HSP70 levels 14 days after onset were higher in AMI patients with heart failure (n=15) than in those without heart failure. In our in vitro study, HSP70-stimulated monocytes resulted in dose-dependent TLR4 expression and release of inflammatory cytokines. TLR4 antibody inhibited inflammatory cytokines release.

CONCLUSIONS

Elevated circulating levels of HSP70 may be involved in TLR4 signal-mediated immune response and the progression of heart failure after AMI.

Myocardial Ischemia Induces Interleukin-6 and Tissue Factor Production in Patients With Coronary Artery Disease

BACKGROUND

Interleukin-6 (IL-6) and macrophage colony stimulating factor plasma levels are elevated in acute coronary syndromes. IL-6 has an inherent negative inotropic action and, with tissue factor (TF), mediates the ischemia-reperfusion myocardial injury. We hypothesized that inducible ischemia leads to cytokine production, TF expression, and consequently persistent left ventricular dysfunction after dobutamine stress echocardiography (DSE) in coronary artery disease patients.

METHODS AND RESULTS

DSE was performed in 103 patients with angiographically documented coronary artery disease. Blood samples were obtained at rest, at peak stress, and 30 minutes after cessation of dobutamine infusion for measurement of macrophage colony stimulating factor, IL-6, and TF. New or worsening wall motion abnormalities at peak stress and their duration into recovery were noted. Median IL-6 and TF levels were increased at peak stress and at 30 minutes into recovery compared with rest (2.7 and 2.4 versus 2.1 pg/mL for IL-6, 310 and 385 versus 266 pg/mL for TF [P<0.01] in patients with an ischemic response; n=55). Compared with rest, a greater release of IL-6 at peak stress and recovery was observed in patients with increasing number of ischemic segments at peak DSE (2 versus 3 to 4 versus 5 to 6 versus 7 to 8 segments; P=0.03). The time to recovery of wall motion abnormalities was also associated with IL-6 levels at peak stress and recovery (r=0.51 and r=0.39, P<0.05). Macrophage colony stimulating factor levels remained unchanged throughout DSE.

CONCLUSIONS

Reversible ischemia induced during DSE increases IL-6 and TF plasma levels. IL-6 is related to the extent of left ventricular dysfunction at peak stress and to persistent LV dysfunction during recovery.

Proinflammatory cytokines and myocardial viability in patients after acute myocardial infarction

BACKGROUND

Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) can potentiate heart muscle damage during acute myocardial infarction (AMI). Whether changes in their plasma levels after AMI are dependent on the presence of myocardial viability is unclear. The aim of the study was to estimate the relation of time course of plasma TNF-alpha and IL-6 and the presence of reversible and irreversible myocardial dysfunction in patients early after AMI treated thrombolytically.

MATERIAL AND METHODS

Patients (54; mean age 60.4 +/- 11.7 years) with AMI plasma TNF-alpha and IL-6 were evaluated on the 2nd, 10th and 30th day after thrombolysis. Based on the response of dysfunctional segments of myocardium during dobutamine stress echocardiography performed on the 10th day, patients were divided into four groups: A, sustained improvement in contractility; B, biphasic (improvement followed by worsening); C, only worsening; D, no change. Twenty-two healthy persons served as controls.

RESULTS

On the 2nd day, all four groups of patients demonstrated increased levels of TNF-alpha and IL-6 and did not differ among one another regarding both cytokines. On the 10th day, plasma TNF-alpha and IL-6 decreased in each group and were the lowest in group A, intermediate in group B and the highest in groups C and D. On the 30th day, both cytokines were not different among all studied groups.

CONCLUSION

Elevated plasma TNF-alpha and IL-6 early after AMI decreased more quickly in patients with dysfunctional myocardium comprising not only necrotic but also viable segments. This decline is attenuated by the presence of residual ischemia.

Activated toll-like receptor 4 in monocytes is associated with heart failure after acute myocardial infarction

Peripheral monocytosis may affect the development of heart failure (HF) after acute myocardial infarction (AMI). Activated toll-like receptor (TLR) 4 in monocytes plays an important role in the synthesis of proinflammatory cytokines. We examined TLR4 expression in monocytes, which may be a possible source of proinflammatory cytokines in AMI. Sixty-five patients with AMI and 20 healthy subjects (HS) were studied. Monocytes were isolated from peripheral blood on days 1 and 14 after the onset of AMI. TLR4 levels in monocytes were measured using real-time RT-PCR and flow cytometry. Generation capacity was evaluated by TLR4 levels and cytokine concentrations in the culture medium with lipopolysaccharide (LPS) stimulation. On day 1 after onset, baseline levels of TLR4 and plasma proinflammatory cytokines, notably IL-6 and TNF-alpha, were higher in AMI patients than in HS. These levels remained elevated in AMI patients 14 days after onset. Generation capacities of TLR4 and proinflammatory cytokines (IL-2, IL-6, IL-8, IL-10, GM-CSF and TNF-alpha) were increased in AMI patients compared to HS. LPS-stimulated TLR4 levels were positively correlated with IL-6 and TNF-alpha levels in AMI patients. Baseline TLR4 levels and plasma proinflammatory cytokine (IL-6, GM-CSF and TNF-alpha) levels were higher in AMI patients with HF (n = 22) than in those without HF. Generation capacities of TLR4 and proinflammatory cytokines (IL-6, GM-CSF and TNF-alpha) were greater in AMI patients with HF than in those without HF. Activation of TLR4 through a myocytic inflammatory reaction is associated with HF after AMI. These observations suggest that TLR4 signaling in monocytes may play a role in the development of HF after AMI.

The role of cytokines in unstable angina

A growing body of evidence suggests that inflammation plays a major role in the pathogenesis of unstable angina; this evidence is mainly derived from the prognostic role of the acute phase reaction proteins, such as C-reactive protein (CRP) and fibrinogen. Since the production of acute phase protein is under the control of the pro-inflammatory cytokines, it is probable that citokines, such as tumour-necrosis factor (TNF)-alpha, interleukin (IL)-1 and IL-6 are involved in the same process. Indeed, elevated levels of IL-1 and IL-6 have been found by our group and by others, in patients with acute coronary syndromes. Cytokines may have procoagulant effects, directly or via endothelial dysfunction, and may induce plaque vulnerability or rupture. They may also be responsible for the activation of other cells, as neutrophils or mast-cells. Although it is conceivable that activated lymphocytes, via interferon-gamma production, are responsible for macrophage activation and cytokine production in unstable angina, the trigger and the precise mechanism of this event are still unknown. The multiple roles of cytokines in unstable angina suggest that a targeted anti-inflammatory therapy might be a novel approach in the future for the treatment of this syndrome.

Activated tumour necrosis factor-α shedding process is associated with in-hospital complication in patients with acute myocardial infarction

TACE [TNF-α (tumour necrosis factor-α)-converting enzyme] plays an essential role in the shedding of TNF-α, which could affect the outcome of AMI (acute myocardial infarction). To investigate the clinical significance of the TACE–TNF-α system in AMI, we examined TACE-mediated TNF-α synthesis in PBMCs (peripheral blood mononuclear cells), which are a possible source of TNF-α in AMI. Forty-one patients with AMI and 15 healthy subjects (HS) were enrolled in the present study. PBMCs were isolated from peripheral blood on day 1 and 14 after the onset of AMI. TACE and TNF-α mRNA levels and intracellular median fluorescence intensity were measured by real-time RT (reverse transcriptase)–PCR and flow cytometry respectively. TACE-mediated TNF-α production was evaluated in cultured PBMCs with PMA, which is known to activate TACE. Spontaneous TACE and TNF-α levels were higher in AMI patients than in HS (P<0.001). TACE and TNF-α levels in PMA-stimulated PMBCs were markedly increased in AMI patients compared with HS (P<0.001). There was a positive correlation between TACE and TNF-α levels in AMI. Although spontaneous and stimulated levels of TACE and TNF-α decreased 14 days after the onset of AMI, levels in AMI patients were higher than in HS. In AMI patients with in-hospital complications (n=15; pump failure in ten, recurrent myocardial infarction in one, malignant ventricular arrhythmia in three and cardiac death in one), spontaneous and stimulated levels of TACE and TNF-α were higher than in patients without complications (P<0.01). These levels were higher in AMI patients with in-hospital complications 14 days after onset. These results demonstrate that TACE-mediated TNF-α maturation in PBMCs may play an important role in poor outcomes from AMI, suggesting that TACE may be a potential target for the inhibition of cellular TNF-α production in AMI.

Simvastatin Regulates Myocardial Cytokine Expression and Improves Ventricular Remodeling in Rats after Acute Myocardial Infarction

PURPOSE

Studies have showed that inflammatory cytokines were involved in the process of left ventricular (LV) remodeling after acute myocardial infarction (AMI), anti-inflammation treatment ameliorated LV remodeling and improved cardiac performance. Hydroxymethylglutary coenzyme A reductase inhibition (statins) could affect the expression of inflammatory cytokines. We hypothesized that statins have beneficial effects on early LV remodeling and cardiac performance in rats with AMI by modulating the production of inflammatory cytokines.

METHODS

Rats with AMI were treated with placebo or simvastatin (gastric gavage) for 4 weeks. The pro-inflammatory cytokines: tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and the anti-inflammatory cytokine: IL-10 excreted by cardiac myocytes was examined. Echocardiography, hemodynamics and collagen type I production were measured to evaluate LV remodeling and cardiac function.

RESULTS

The mRNA expression and protein production of TNF-alpha, IL-1beta, IL-6 and IL-10 in AMI group were significantly elevated compared with sham rats. Simvastatin markedly attenuated the production of TNF-alpha, IL-1beta, IL-6 and increased IL-10 levels in the noninfarcted and infarcted regions, reduced collagen deposition in the noninfarcted myocardium and improved left ventricular function. However simvastatin did not alter plasma lipids.

CONCLUSIONS

Simvastatin ameliorates early LV remodeling and improve cardiac function after AMI. Simultaneously, it decreased pro-inflammatory and increased anti-inflammatory cytokines, which suggests, but does not prove, a causal relationship independent of plasma lipid-lowering effects.

Possible involvement of macrophage-colony stimulating factor in the pathogenesis of cardiac dysfunction in hemodialysis patients

In patients with end stage renal disease on hemodialysis (HD), left ventricular (LV) function is frequently impaired. However, the mechanism of the LV dysfunction is totally unknown. It has been suggested that overproduction of nitric oxide induced by inflammatory cytokines may contribute to the LV dysfunction in some diseased states. In this study, we examined whether inflammatory cytokines play a role in the altered LV function in HD patients. The plasma concentrations of 5 major inflammatory cytokines, including interleukin (IL)-1alpha, IL-1beta, IL-6, tumor necrosis factor-alpha, and macrophage-colony stimulating factor (M-CSF) were measured by enzyme immunoassay with horseradish peroxidase in 18 consecutive patients on HD and in 16 control subjects. Then, we examined the relationship between plasma concentrations of M-CSF and LV ejection fraction (EF) on echocardiography. Among the inflammatory cytokines examined, only the plasma concentrations of M-CSF were significantly elevated in patients on HD as compared to the control subjects. There was no significant change in the M-CSF concentrations before and after HD. Furthermore, there was a significant negative correlation between the plasma concentrations of M-CSF and LVEF. These results suggest that elevated levels of plasma M-CSF may exist prior to the development of LV dysfunction observed in HD patients.

Changes in the Expression of Leukocyte Adhesion Molecules Throughout the Acute Phase of Myocardial Infarction

Since increased leukocytes within days after the onset of acute myocardial infarction (AMI) may reflect an increased expression of the adhesion molecules necessary for effective endothelial transmigration, we evaluated the expression of adhesion molecules on leukocytes throughout the acute phase of MI. We measured the number of leukocytes and enzymes and the expression levels of CD11a, CD18, very-late-after-activation antigen-4 alpha, intracellular adhesion molecule-1 (ICAM-1) and L-selectin by flow cytometry before and after coronary intervention, and at 6, 12, 18, 48 and 72 hours of MI in 5 patients (AMI group). As controls, we measured these parameters in 5 patients who had been diagnosed with angina pectoris and underwent coronary intervention (AP group). In the AMI group the expression of monocyte CD11a was significantly increased after 6 hours, and CD18 and ICAM-1 expression were also significantly increased after 12 hours, whereas that of monocyte L-selectin was increased after 72 hours. In addition, the increased monocyte CD11a was accompanied by an increased number of monocytes and a greater expression of CD11a per cell in the AMI group. In conclusion, since CD11a and CD18 are expressed on the cell surface as a heterodimer and ICAM-1 is a ligand for CD11a/CD18, their increased expression may contribute to their adhesion to endothelium in ischemic regions and may lead to the formation of microaggregates.

Increases in Interleukin-6 and Matrix Metalloproteinase-9 in the Infarct-Related Coronary Artery of Acute Myocardial Infarction

BACKGROUND

To elucidate the involvement of inflammation in coronary artery occlusion, the regional changes in cytokines and matrix metalloproteinases (MMPs) in the infarct-related coronary artery were determined in patients with acute myocardial infarction.

METHODS AND RESULTS

Cardiac catheterization was carried out within 24 h of the onset of infarction in 36 patients. Blood samples were collected from the infarct-related coronary artery, the ascending aorta and the peripheral vein. Plasma interleukin (IL)-6 concentrations were elevated in all 3 samples. Particularly, the plasma IL-6 concentrations were 14.4 pg/ml in the infarct-related coronary artery, a value significantly greater than the respective 8.0 pg/ml and 6.5 pg/ml in the ascending aorta and peripheral vein. Plasma IL-6 concentrations in the infarct-related coronary artery had positive correlation with all of the following references measured by intravascular ultrasound: external elastic membrane cross-sectional area (EEM-CSA) (r=0.47, p<0.01), lesion EEM-CSA (r=0.51, p<0.01) and plaque area (r=0.48, p<0.01). MMP-9 was increased regionally in the infarct-related coronary artery, at 11.8 ng/ml vs 8.2 ng/ml in the ascending aorta (p<0.001).

CONCLUSIONS

The present findings suggest that IL-6 at least is released from the ruptured vulnerable atherosclerotic plaque and that regional activation of macrophages is involved in the occlusive process of coronary artery in acute myocardial infarction.

Interleukin-6 and tumor necrosis factor alpha in relation to myocardial infarct size and collagen formation

BACKGROUND

Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) levels increase after acute myocardial infarction (AMI) in humans. Experimental data suggest that these cytokines regulate the initiation of scar formation after AMI. We investigated the interrelationships of IL-6 and TNF-alpha, tissue injury, infarct size, cardiac function, and collagen formation in humans.

METHODS

Serum and plasma samples were taken on 93 patients receiving thrombolytic treatment for their first AMI. Collagen formation was evaluated by measuring concentrations of serum aminoterminal propeptide of type III procollagen (PIIINP).

RESULTS

IL-6 levels increased by 44% (P<.001) and peaked at 24 hours. Peak IL-6 levels correlated positively with area under the curve of creatine kinase MB mass (r=.31, P<.01), peak troponin T level (r=.34, P<.005), and PIIINP measured at discharge (r=.46, P<.001). There were no changes in TNF-alpha levels, and patients with left ventricular dysfunction (EF<40%) had similar TNF-alpha levels as those with preserved left ventricular function.

CONCLUSIONS

IL-6 may regulate collagen formation and thus remodeling of the left ventricle after AMI. In addition, TNF-alpha measurement is useless in the assessment of infarct size or left ventricular function during the immediate post-infarction period.

Inhibition of the renin-angiotensin system: no effect on circulating macrophage colony-stimulating factor levels in acute myocardial infarction

Macrophage colony-stimulating factor, which induces proliferation and differentiation, and activation of monocytes and macrophages, plays an important role in the vulnerability of atheromatous plaques as well as the formation of atherosclerotic lesions. We measured serum concentrations of macrophage colony-stimulating factor in patients with acute myocardial infarction and also investigated the effects of early administration of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker on circulating macrophage colony-stimulating factor levels in these patients. The patients were divided randomly into 3 therapeutic groups; perindopril, candesartan, and control (without perindopril and candesartan) groups, and the drugs were administered within 24 to 36 hours after the onset of acute myocardial infarction. Serum macrophage colony-stimulating factor concentrations in acute myocardial infarction patients at the time of admission were significantly higher than those in healthy control subjects. The macrophage colony-stimulating factor levels in the patients decreased gradually after admission, but remained significantly higher than those in control subjects for 14 days. There were no significant differences in serum macrophage colony-stimulating factor levels among the 3 therapeutic groups during this study period. In conclusion, circulating macrophage colony-stimulating factor levels are elevated during the course of acute myocardial infarction, and inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker does not affect these levels.

Induction of apoptosis and ubiquitin hydrolase gene expression by human serum factors in the early phase of acute myocardial infarction

The physiologic events leading to apoptosis in myocardial infarction and the molecules involved in the death process have not been clarified unequivocally. We developed a method to search for serum factors that induce apoptosis of human cells, using serum obtained from patients within 1 day of the onset of acute myocardial infarction (AMI). Serum factors were found to have the ability to increase the caspase-3 activity levels in human RSa cells, which are susceptible to apoptosis inducers. The factors obtained from AMI patients by elution at about 0.5 mol/L KCl from a dye-ligand column were named AMI-SFs (serum factors from AMI). Electrophoretic analysis showed DNA fragmentation in AMI-SF-treated RSa cells, but not in RSa cells treated with fractions from AMI patients 1 week after clinical onset of illness. AMI-SF-induced DNA fragmentation was also demonstrated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling analysis, whereas a suppression of fragmentation was seen in RSa cells treated with AMI-SFs in combination with a caspase-3 inhibitor. The increase in caspase-3 activity was not inhibited by neutralizing antibodies to tumor necrosis factor-alpha, interleukin-6, human interferon-beta, or interferon-gamma. Polymerase chain reaction-based messenger RNA differential display and Northern blotting revealed an increase in the messenger RNA expression level of human ubiquitin hydrolase in AMI-SF-treated RSa cells. Antisense oligonucleotides for ubiquitin hydrolase inhibited the increase in caspase-3 activity. These findings suggested that serum from AMI patients in the acute phase contains factors that induce apoptosis, possibly by inducing the expression of the ubiquitin hydrolase gene, at least in the human cells tested.

Prognostic significance of plasma concentrations of transforming growth factor-beta in patients with coronary artery disease

BACKGROUND

Cytokines play an important role in modulating inflammatory and proliferative responses, including atherosclerosis. Transforming growth factor-beta (TGF-beta) and macrophage-colony stimulating factor (M-CSF) are one of the major antiinflammatory and proinflammatory cytokines, respectively. We have previously demonstrated that plasma concentrations of TGF-beta are decreased while those of M-CSF are increased in patients with coronary artery disease (CAD). In this study, we examined whether those alterations in plasma levels of cytokines have a prognostic significance in patients with CAD.

METHODS AND RESULTS

Sixty-eight consecutive patients with proven CAD were studied. The plasma concentrations of TGF-beta and those of M-CSF were measured by enzyme-linked immunosorbent assay (ELISA). They were divided into groups: high (> or =6 ng/ml, n = 19) and low (<6 ng/ml, n = 49) TGF-beta groups and high (>500 ng/ml, n = 52) and low (< or =500 ng/ml, n = 16) M-CSF groups. The long-term prognosis of these patients was prospectively followed up for a mean period of 979 +/- 27 days. The prognosis was analyzed by Kaplan-Meier analysis in terms of total survival, survival without myocardial infarction, survival without cardiovascular events and survival without coronary interventions. The analysis showed that the low TGF-beta group had a significantly poor prognosis in terms of survival without cardiovascular events and survival without coronary interventions as compared with the high TGF-beta group (both P < 0.05), while other prognoses were comparable between the two groups. By contrast, no significant prognostic influence was noted regarding M-CSF.

CONCLUSIONS

These results suggest that plasma concentrations of TGF-beta may have a prognostic significance in patients with CAD.

Prognostic significance of peripheral monocytosis after reperfused acute myocardial infarction:a possible role for left ventricular remodeling

OBJECTIVES

The aim of this study was to determine the significance of peripheral monocytosis in clinical outcome after reperfused acute myocardial infarction (AMI), especially relating to post-infarct left ventricular (LV) remodeling.

BACKGROUND

Peripheral monocytosis occurs two to three days after AMI, reflecting infiltration of monocytes and macrophages into the necrotic myocardium. However, the prognostic significance of peripheral monocytosis after AMI remains to be determined.

METHODS

A total of 149 patients with first Q-wave AMI were studied. White blood cell (WBC) count, percentage of monocytes and serum C-reactive protein level were measured every 24 h for four days after the onset of AMI. We assessed association between peripheral monocytosis and prognosis including pump failure, LV aneurysm and long-term outcome after AMI.

RESULTS

Patients with pump failure (p < 0.0001) or LV aneurysm (p = 0.005) had higher peak monocyte counts than those without these complications. Predischarge left ventriculography revealed that peak monocyte count was positively correlated with LV end-diastolic volume (p = 0.024) and negatively correlated with ejection fraction (p = 0.023). Multivariate analyses showed that peak monocyte count > or = 900/mm(3) was an independent determinant of pump failure (relative risk [RR] 9.83, p < 0.0001), LV aneurysm (RR 4.78, p = 0.046) and cardiac events (RR 6.30, p < 0.0001), including readmission for heart failure, recurrent myocardial infarction and cardiac deaths, including sudden deaths.

CONCLUSIONS

Peripheral monocytosis is associated with LV dysfunction and LV aneurysm, suggesting a possible role of monocytes in the development of LV remodeling after reperfused AMI.

Elevated interleukin-1beta in pericardial fluid of patients with ischemic heart disease

BACKGROUND

Inflammatory cytokines may play an important role in the pathogenesis of atherosclerosis and heart failure. We have previously demonstrated that long-term treatment with interleukin (IL)-1beta in the coronary artery and myocardium promotes coronary arteriosclerosis and impairs cardiac function, respectively. The cytokines in pericardial fluid may reflect the extent of coronary atherosclerosis and may also directly promote the atherosclerotic process. This study was designed to examine the significance of cytokine concentrations in pericardial fluid of patients with cardiovascular disease.

METHODS

We measured concentrations of 10 major cytokines in the pericardial fluid of 56 consecutive patients obtained during open heart surgery, 27 with ischemic heart disease (IHD group), 21 with valvular heart disease (VHD group) and eight with congenital heart disease (CHD group).

RESULTS

The pericardial concentrations of IL-1beta (pg/ml) were significantly higher in the IHD group (60 +/- 15) than in the VHD (29 +/- 5) or the CHD group (26 +/- 4) (P < 0.05 both). There was no significant difference in pericardial concentrations of other cytokines among the three groups. In the IHD group, the IL-1beta concentrations were significantly elevated in patients who had undergone emergency operations or in those with unstable angina.

CONCLUSIONS

These results suggest that pericardial concentrations of IL-1beta may reflect the extent of ischemic heart disease and that elevated IL-1beta concentrations in pericardial fluid may also directly promote the process of coronary atherosclerosis.

Chemokine expression in coronary circulation after coronary angioplasty as a prognostic factor for restenosis

Recent studies have clarified the significance of chemokines in cardiovascular diseases, such as development of atherosclerosis, atheromatous plaque rupture and restenosis after coronary angioplasty. We investigated changes in chemokine expression in the coronary circulation induced by percutaneous transluminal coronary angioplasty (PTCA) and their clinical significance. We examined 40 patients with angina pectoris who underwent elective PTCA for isolated stenotic lesions of the left coronary artery. Eight patients received PTCA only, 14 percutaneous transluminal rotational atherectomy and 18 stent implantation. Venous blood samples were obtained from the coronary sinus before, and immediately after as well as 4 and 24 h after PTCA. Plasma levels of interleukin (IL)-8, macrophage-colony stimulating factor (M-CSF) and monocyte chemoattractant protein-1 (MCP)-1 were measured by enzyme-linked immunosorbent assay. Plasma levels of M-CSF in the coronary sinus blood showed significant increases 4 and 24 h after PTCA. On the other hand, plasma MCP-1 levels did not change significantly during a 24-h observation period after PTCA. Immunoreactive IL-8 was not detected in any patients before or after PTCA. A significant positive correlation was found between plasma M-CSF levels 24 h after PTCA and late loss index 6 months after the procedure. Plasma levels of M-CSF 24 h after PTCA were significantly higher in patients with than in those without late restenosis. PTCA induced increases in plasma levels of M-CSF in the coronary circulation. Increased M-CSF expression may be involved in neointima formation at injured vessels through activation of mononuclear phagocytes.

Role of cytokines in the pathogenesis of restenosis after percutaneous transluminal coronary angioplasty

BACKGROUND

Inflammatory cytokines play an important role in mediating inflammatory/proliferative responses including atherosclerosis. However, their role in the pathogenesis of restenosis after percutaneous transluminal coronary angioplasty (PTCA) remains to be clarified.

OBJECTIVE

To determine plasma levels of inflammatory cytokines as well as cytokine-generation capacities of monocytes before PTCA and after the follow-up period.

METHODS

Plasma levels of cytokines in 34 consecutive patients before and 3-6 months after PTCA were measured by enzyme-linked immunosorbent assay. We measured the plasma levels of macrophage-colony-stimulating factor (MCSF) and transforming growth factor-beta. Cytokine-generation capacities of monocytes were also measured by a whole-blood induction method with lipopolysaccharide. The levels of cytokines measured for assessment of the capacities included those of interleukin-1alpha, interleukin-1beta, interleukin-6, granulocyte-colony-stimulating factor, tumor necrosis factor-alpha and interferon-gamma.

RESULTS

Plasma levels of MCSF in patients without restenosis (n = 20) decreased significantly (from 1460+/-138 microg/ml before PTCA to 1039+/-125 microg/ml after the follow-up period, P < 0.01), whereas those in patients with restenosis (n = 14) increased significantly (from 1107+/-105 microg/ml before PTCA to 1039+/-125 microg/ml after the follow-up period, P < 0.05). We noted a positive correlation between the increase in plasma levels of MCSF and the extent of loss of lumen by restenosis. Cytokine-generation capacities of monocytes for interleukin-1alpha and interleukin-1beta of patients with restenosis significantly increased but those of patients without restenosis did not. Furthermore, plasma levels of C-reactive protein decreased significantly only in patients without restenosis after the follow-up period.

CONCLUSIONS

These results suggest that inflammatory changes mediated by cytokines may be involved in the pathogenesis of restenosis after PTCA.

Expression of an endothelial-type nitric oxide synthase isoform in human neutrophils: modification by tumor necrosis factor-alpha and during acute myocardial infarction

OBJECTIVES

The purpose of this study was to determine whether human neutrophils express an endothelial-type nitric oxide synthase (eNOS), and to study the effect of tumor necrosis factor-alpha (TNF-alpha) on its expression.

BACKGROUND

Several studies have demonstrated the presence of a constitutively expressed nitric oxide svnthase (NOS) in neutrophils. Cardiovascular disease is characterized by increased levels of plasma TNF-alpha, a cytokine that has demonstrated eNOS messenger ribonucleic acid (mRNA) destabilization in cultured endothelial cells.

METHODS

Neutrophils were obtained from healthy volunteers and from patients with acute myocardial infarction (AMI).

RESULTS

Human neutrophils express eNOS mRNA and eNOS protein. Stimulation of neutrophils with TNF-alpha decreased eNOS protein expression by reducing eNOS mRNA stabilization. In the present study, we also show that the cytosol of human neutrophils contains proteins that bind to a specific region within the 3'-untranslated region (3'-UTR) of eNOS mRNA. Tumor necrosis factor-alpha increased the binding of the cytosolic proteins to the 3'-UTR of eNOS mRNA. Simvastatin reduced the TNF-alpha-related binding activity of neutrophil cytosolic proteins to eNOS mRNA, which was associated with its protective effect on eNOS protein expression. The in vivo reproduction of the in vitro findings was performed in neutrophils obtained from patients with AMI and showed a diminished expression of eNOS protein, which was associated with increased binding of the cytosolic proteins.

CONCLUSIONS

These observations demonstrate that human neutrophils express eNOS, which is downregulated by TNF-alpha and during AMI. This effect is associated with increased binding of neutrophil cytosolic proteins to the 3'-UTR of eNOS mRNA.

Expression of matrix metalloproteinases in patients with acute myocardial infarction

This study investigated the clinical significance of matrix metalloproteinases (MMPs) in acute myocardial infarction (AMI) and the involvement of peripheral blood mononuclear cells (PBMCs), which are a possible source of MMPs in AMI. Forty patients with AMI were recruited. Plasma and PBMCs were isolated from peripheral blood on days 1, 7, 14 and 21 after the onset of AMI. Levels of MMP-1 and MMP-2 were measured by enzyme-linked immunosorbent assay. The MMP-1 level in the culture medium of PBMCs after incubation for 24h was designated as 'PBMC-MMP-1 level.' Plasma MMP-1 did not significantly change during the course of AMI, but the plasma MMP-2 levels increased gradually after the onset of AMI with maximum elevation on day 21 after onset. Plasma MMP-2 activity also became significantly elevated during the course of AMI. PBMC-MMP-1 levels in the patients were significantly higher than those in control subjects over the course of AMI. Significant positive correlations were observed between maximum PBMC-MMP-1 levels and maximum plasma C-reactive protein levels (r=+0.55, p<0.01) and left ventricular end-diastolic volume index (r=+0.63, p<0.001). In conclusion, plasma MMP-2 levels and activity and MMP-1 production by PBMCs are increased in patients with AMI. Inflammation after AMI may enhance production of MMP-1 by PBMCs. These changes may play an important role in the ventricular remodeling that occurs after AMI by promoting the degradation of the extracellular matrix.

IL-6 and IL-1 receptor antagonist in stable angina pectoris and relation of IL-6 to clinical findings in acute myocardial infarction

OBJECTIVES

To determine if increased inflammatory activity, as reflected by interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) levels, is present in patients with stable angina pectoris and if IL-6 levels on admission to the coronary care unit in patients with acute myocardial infarction (AMI) are related to heart failure and fever response.

SUBJECTS AND METHODS

We studied 28 patients with stable angina pectoris enrolled for coronary angiography, and compared them with sex- and age-matched controls. Thirty-four patients with AMI were studied and samples for determination of IL-6 levels were taken on admission within 36 h of onset of symptoms. IL-6 and IL-1ra were determined in serum by enzyme immunoassay.

RESULTS

Levels of IL-6 and IL-1ra were higher in patients with stable angina pectoris than in controls (mean 4.6 +/- 3.6 vs. 3.0 +/- 2.9 ng L-1, P < 0.03, and 774 +/- 509 vs. 490 +/- 511 ng L-1, P < 0.01, respectively). IL-6 and IL-1ra levels were not related to angiographic findings. IL-6 levels were high in patients with AMI (38.9 +/- 75.6 ng L-1). Patients with prolonged fever (duration > 4 days) had higher IL-6 levels (94.7 +/- 138.2 vs. 21.7 +/- 29.7 ng L-1, P < 0.05). IL-6 levels were not related to heart failure.

CONCLUSIONS

Our results indicate that increased inflammatory activity is present not only in acute coronary syndromes, but also in a chronic form of ischaemic heart disease, giving further evidence for a central role of inflammatory processes in coronary artery disease. With regard to AMI, we found increased inflammatory activity in patients with prolonged fever.

Expression of vascular endothelial growth factor in patients with acute myocardial infarction

OBJECTIVE

The purpose of this study was to investigate the clinical significance of vascular endothelial growth factor (VEGF) in acute myocardial infarction (AMI). We also examined the involvement of peripheral blood mononuclear cells (PBMCs), which are a possible source of VEGF in AMI.

BACKGROUND

VEGF is a potent endothelial cell-specific mitogen and could affect the outcome of AMI.

METHODS

Thirty patients with AMI were used for this study. Serum and PBMCs were isolated from peripheral blood on days 1, 7, 14 and 21 after the onset of AMI. PBMCs were cultured at a density of 5 x 10(6) cells/ml for 24 h. VEGF levels in serum and the culture media were measured by enzyme-linked immunosorbent assay using a specific anti-human VEGF antibody.

RESULTS

Serum VEGF levels elevated gradually after the onset of AMI and reached a peak on day 14. VEGF levels in the culture medium of PBMCs after incubation for 24 h (PBMC-VEGF) were maximally elevated 7 days after the onset. Maximum serum VEGF levels showed significant positive correlations with maximum creatine phosphokinase (CPK) levels (r = +0.70, p < 0.001), but maximum PBMC-VEGF levels did not correlate with maximum CPK levels. Patients showing improvement in left ventricular systolic function during the course of AMI showed significantly higher PBMC-VEGF levels than patients without improvement.

CONCLUSIONS

The extent of myocardial damage contributes to the elevation of serum VEGF levels in AMI. VEGF produced by PBMCs may play an important role in the improvement of left ventricular function by promoting angiogenesis and reendothelialization after AMI.

Clinical significance of increased plasma concentration of macrophage colony-stimulating factor in patients with angina pectoris

OBJECTIVES

To determine the effect of macrophage colony-stimulating factor (MCSF) on atherogenesis in patients with coronary artery disease (CAD), we assessed the relation between the plasma concentration of MCSF and the incidence of acute coronary events in patients with CAD.

BACKGROUND

Cytokines such as MCSF play a central role in inflammatory and proliferative responses in patients with acute coronary syndromes. However, the effect of MCSF on the clinical course in patients with CAD is still not known.

METHODS

We measured the plasma MCSF concentration in 142 patients with documented CAD (62 +/- 9 years) and followed up for a mean period of 14 +/- 6 months. The study included 97 patients with stable angina (SA), 45 patients with unstable angina (UA) and 22 age-matched control subjects. The predictors of coronary events were analyzed by using a Cox proportional hazards model.

RESULTS

The mean plasma MCSF concentration in patients with UA was significantly higher than that in patients with SA and in control subjects (981 +/- 277 vs. 693 +/- 223 vs. 680 +/- 158 pg/ml, p < 0.001). The mean plasma MCSF concentration in the 20 patients with coronary events was significantly higher than that in patients without coronary events (1,192 +/- 232 vs. 690 +/- 213 pg/ml, p < 0.001). The predictors of unfavorable outcome were an increased MCSF concentration, the presence of CAD and a low ejection fraction.

CONCLUSIONS

These findings suggest that an increased circulating MCSF concentration reflects atherosclerotic progression in patients with CAD and predicts future cardiac events.

Decreased soluble interleukin-6 receptor in patients with acute myocardial infarction

BACKGROUND

The plasma level of interleukin-6 (IL-6), a proinflammatory cytokine, has been reported to be elevated in patients with acute myocardial infarction (AMI). In addition to a specific cell-surface IL-6 receptor, a soluble IL-6 receptor (sIL-6R) exists in plasma as an extracellular domain of glycoprotein 80. The pathophysiologic roles of IL-6 and sIL-6R in AMI are still unknown.

METHODS AND RESULTS

We measured plasma levels of IL-6 and sIL-6R in 17 patients with AMI to evaluate changes over time at 11 points in the acute phase and compared them with parameters of inflammation, myocardial injury, and atherosclerosis. IL-6 showed a triphasic increase with peaks at 3 hours (276.2 +/- 50.0 pg/mL), 2 days (153.6 +/- 35.7 pg/mL), and 5 days (180.7 +/- 52.3 pg/mL) after the onset of AMI. sIL-6R had biphasic dips at 12 hours (31.1 +/- 4.1 ng/mL) and 3 days (29.9 +/- 1.5 ng/mL) after the onset on AMI. The time-dependent changes in IL-6 paralleled those in sIL-6R from onset to 5 days. Thereafter, the changes in IL-6 and sIL-6R varied; that is, IL-6 gradually decreased from 5 days to 4 weeks, whereas sIL-6R gradually increased from 5 days to 4 weeks. Significant positive correlations were observed between the absolute increase in IL-6 and the decrease in sIL-6R and the changes in white blood cell count, erythrocyte sedimentation rate, C-reactive protein, creatine kinase, and lactic dehydrogenase. Neither IL-6 nor sIL-6R strongly correlated with parameters of coronary atherosclerosis.

CONCLUSIONS

These results demonstrate that IL-6 and sIL-6R are associated with the processes of inflammation and myocardial injury during the acute phase of AMI.

Increased proinflammatory cytokines in patients with chronic stable angina and their reduction by aspirin

BACKGROUND

Proinflammatory cytokines released by injured endothelium facilitate interaction of endothelial cells with circulating leukocytes and thus may contribute to development and progression of atherosclerosis. We investigated whether cytokines and C-reactive protein (CRP) are indicative of myocardial ischemia or of diseased vessels and whether they are influenced by aspirin treatment in patients with chronic stable angina.

METHODS AND RESULTS

Plasma macrophage colony stimulating factor (MCSF), IL-1b, IL-6, and CRP were measured in 60 stable patients after 48-hour Holter monitoring and in 24 matched controls. All patients had angiographic documentation of disease and positive exercise ECGs. Patients with ischemia on Holter monitoring (n=40) received aspirin or placebo in a 6-week, randomized, double blind, crossover trial. Blood sampling was repeated at the end of each treatment phase (3 weeks). Compared to controls, patients had more than twice median MCSF (800 versus 372 pg/mL), IL-6 (3.9 versus 1.7 pg/mL), and CRP (1.25 versus 0.23 mg/L) levels (P<0.01 for all comparisons). MCSF was related to ischemia on Holter monitoring (P<0.01), to low ischemic threshold during exercise (P<0.01), and together with IL-1b to number of diseased vessels (P<0.05). MCSF, IL-6, and CRP were all reduced after 6 weeks of aspirin treatment (P<0.05).

CONCLUSIONS

These findings suggest that cytokines are associated with both ischemia and anatomic extent of disease in patients with stable angina. Reduced cytokine and CRP levels by aspirin may explain part of aspirin's therapeutic action.

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.

Pimobendan inhibits the production of proinflammatory cytokines and gene expression of inducible nitric oxide synthase in a murine model of viral myocarditis

OBJECTIVES

This study was designed to examine the effects of pimobendan in a murine model of viral myocarditis in relation to proinflammatory cytokine production and nitric oxide (NO) synthesis by inducible NO synthase (iNOS) in the heart.

BACKGROUND

Pimobendan has been recently confirmed to improve both acute and chronic heart failure. Since the modulation of myocardial necrosis and contractile dysfunction by various proinflammatory cytokines may be partially mediated by the production of nitric oxide, the effects of pimobendan on the production ofproinflammatory cytokines and NO were investigated in an animal model of viral myocarditis involving heart failure.

METHODS

DBA/2 mice were inoculated with the encephalomyocarditis virus. To observe its effect on survival up to 14 days, pimobendan (0.1 mg/kg or 1 mg/kg) or vehicles were given from the day of virus inoculation (day 0) orally once daily. The effects of pimobendan on histological changes, cytokine production, NO production and iNOS gene expression in the heart were studied in mice treated either with pimobendan, 1 mg/kg or with vehicles only, and sacrificed seven days after virus inoculation.

RESULTS

The survival of mice improved in a dose-dependent fashion such that a significant difference (p < 0.02) was found between the higher-dose pimobendan group (20 of 30 [66.7%]) and the control group (11 of 30 [36.7%]). Histological scores for cellular infiltration (1.1+/-0.1 vs. 2.0+/-0.0, p < 0.001), intracardiac tumor necrosis factor (TNF)-alpha (18.2+/-1.8 vs. 35.8+/-4.2 pg/mg heart, p < 0.001) and interleukin (IL)-1beta (9.3 +/-1.2 vs. 26.6+/-7.1 pg/mg heart, p < 0.01) were significantly lower in the mice given pimobendan versus those of the control mice. Interleukin-6 levels (7.1+/-0.8 vs. 9.2+/-1.9 pg/mg heart) were also lower in the mice treated with pimobendan. Furthermore, intracardiac NO production was significantly (p < 0.001) less in the pimobendan group (0.165+/-0.004 nmol/mg heart) than in the control group (0.291+/-0.051 nmol/mg heart), and intracardiac iNOS gene expression in the mice given pimobendan was 74% lower than it was in the control animals (p < 0.01).

CONCLUSIONS

These findings suggest that the beneficial effects of pimobendan in viral myocarditis are partially mediated by the inhibition of both proinflammatory cytokine production and NO synthesis by iNOS.

Effects of cytokines on nitric oxide pathways in human vasculature

Proinflammatory cytokines exert a number of important effects on vascular reactivity. At one end of the spectrum, certain cytokines may induce vascular paresis leading to profound vasodilatation and hyporesponsiveness to constrictor stimuli. This may be relevant to the pathogenesis of septic shock and other types of inflammatory vasodilatation. At the other end of the spectrum, inflammatory cytokines can impair endothelium-dependent dilatation and the endothelium may lose its ability to respond to circulating hormones or autacoids. This effect may case a predisposition to vessel spasm, thrombosis or atherogenesis. Studies in human vessels suggest that interleukin-1 is particularly important as a mediator of inflammatory dilatation; the underlying mechanisms include induction of the inducible isoform of nitric oxide synthase in vascular smooth muscle, or over-production of nitric oxide from the endothelial isoform of nitric oxide synthase. Induction of the enzyme GTP cyclohydrolase 1 and consequent production of tetrahydrobiopterin contributes to the increase in the activity of endothelial nitric oxide synthase. In contrast, tumour necrosis factor-alpha considerably impairs endothelium-dependent relaxation. The mechanisms of these effects are not yet fully understood, but tumour necrosis factor can induce endothelial dysfunction in human endothelial cells in culture, and human blood vessels in vitro and in vivo. The implications of these observations for cardiovascular disease are discussed.

Cytokine generation capacities of monocytes are reduced in patients with severe heart failure

BACKGROUND

Immunologic mechanisms mediated by proinflammatory cytokines have been implicated in the pathogenesis of heart failure. Although monocytes are the major source of such cytokines, little is known about their cytokine generation capacities in heart failure.

METHODS

We measured plasma levels of 7 major monocyte-related cytokines and the generation capacity of monocytes for 3 cytokines (interleukin-1alpha, interleukin-1beta, and tumor necrosis factor-alpha) on stimulation by lipopolysaccharide in 45 consecutive patients with heart failure and 27 controls. The cytokine levels were measured by enzyme-linked immunosorbent assay.

RESULTS

The generation capacities of monocytes for all 3 cytokines were decreased in patients with worsened outcome during hospitalization and the monocyte capacities were significantly reduced in patients with severe heart failure (New York Heart Association class IV). There was a significant negative correlation between the cytokine generation capacities of monocytes and the plasma cortisol levels. Moreover, cortisol significantly inhibited the cytokine production by lipopolysaccharide-stimulated monocytes ex vivo.

CONCLUSIONS

These results indicate that the cytokine generation capacities of monocytes are reduced in patients with severe heart failure, partly because of the negative regulation by cortisol. Because monocytes and cytokines play a central role in immune responses, this reduced monocyte function may be involved in part in the pathophysiology of severe heart failure.

The role of cytokines in the failing human heart

Despite repeated attempts to develop a unifying hypothesis that explains the clinical syndrome of heart failure, no single conceptual paradigm has withstood the test of time. In this regard, recent studies have shown that a class of biologically active molecules, generically referred to as cytokines, are overexposed in heart failure. This article will review recent clinical and experimental material that suggest proinflammatory (stress activated) cytokines such as tumor necrosis factor-alpha (TFN-alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6) may play a role in the pathogenesis of congestive heart failure. The scope of this article includes an overview of the biology of cytokines in the heart, as well as review of the clinical studies that have documented elevated levels of cytokines and cytokine receptors in patients with heart failure.

Cytokine expression increases in nonmyocytes from rats with postinfarction heart failure

Growing evidence suggests that cardiac nonmyocyte cells may play an important regulatory role in the response to myocardial overload and injury via altered expression of paracrine products, such as cytokines and growth factors, but information concerning the cell-specific changes in the expression of these substances in heart-failure models is limited. Therefore, cardiac nonmyocytes were isolated from rats 1 day and 1 and 6 wk after left coronary artery ligation with resulting hemodynamic evidence of heart failure and in sham-operated control animals. mRNAs for tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, transforming growth factors (TGF)-beta1 and TGF-beta3, and type I and type III collagen were measured by Northern analyses. The temporal and quantitative relationships between the expression of these cytokines and collagen and myocyte hypertrophy were determined. mRNA expression of IL-1beta was increased by 1.3-fold at 1 day and 1 wk, and expression of TNF-alpha, IL-1beta, IL-6, TGF-beta1, and TGF-beta3 were increased by 1.4- to 2.1-fold at the 1-wk time point before returning toward baseline at 6 wk. There were significant correlations between the expression of these cytokines and the expression of types I and III collagen, which also peaked at 1 wk. Myocyte hypertrophy was seen first at 6 wk. These observations are consistent with a hypothesis that nonmyocyte cells play a regulatory role in the extracellular matrix changes during postinfarction remodeling and highlight the importance of examining cell-specific changes in gene expression and elucidating the role of cell-to-cell interactions within the myocardium.

Role of nitric oxide and peroxynitrite in the cytokine-induced sustained myocardial dysfunction in dogs in vivo

Studies in vitro suggested that inflammatory cytokines could cause myocardial dysfunction. However, the detailed mechanism for the cytokine-induced myocardial dysfunction in vivo remains to be examined. We thus examined this point in our new canine model in vivo, in which microspheres with and without IL-1beta were injected into the left main coronary artery. Left ventricular ejection fraction (LVEF) was evaluated by echocardiography for 1 wk. Immediately after the microsphere injection, LVEF decreased to approximately 30% in both groups. While LVEF rapidly normalized in 2 d in the control group, it was markedly impaired in the IL-1beta group even at day 7. Pretreatment with dexamethasone or with aminoguanidine, an inhibitor of inducible nitric oxide synthase, prevented the IL-1beta-induced myocardial dysfunction. Nitrotyrosine concentration, an in vivo marker of the peroxynitrite production by nitric oxide and superoxide anion, was significantly higher in the myocardium of the IL-1beta group than in that of the control group or the group cotreated with dexamethasone or aminoguanidine. There was an inverse linear relationship between myocardial nitrotyrosine concentrations and LVEF. These results indicate that IL-1beta induces sustained myocardial dysfunction in vivo and that nitric oxide produced by inducible nitric oxide synthase and the resultant formation of peroxynitrite are substantially involved in the pathogenesis of the cytokine-induced sustained myocardial dysfunction in vivo.

Increased expression of neutrophil and monocyte adhesion molecules LFA-1 and Mac-1 and their ligand ICAM-1 and VLA-4 throughout the acute phase of myocardial infarction: possible implications for leukocyte aggregation and microvascular plugging

OBJECTIVES

This study sought to evaluate expression of adhesion molecules on neutrophils and monocytes throughout the acute phase of myocardial infarction.

BACKGROUND

Neutrophil and monocyte counts increase within days from onset of acute myocardial infarction. Because leukocytes are recruited to the involved myocardial region, we postulated that these activated cells would display an increased expression of adhesion molecules necessary for effective endothelial transmigration.

METHODS

We measured the expression of neutrophil and monocyte lymphocyte function associated antigen-1 (LFA-1), Mac-1, very late after activation antigen-4 (VLA-4) and intercellular adhesion molecule-1 (ICAM-1) by flow cytometry throughout the acute phase of acute myocardial infarction in 25 patients and 10 age-matched control subjects.

RESULTS

Expression of Mac-1 on neutrophils increased significantly, whereas no expression of VLA-4 and ICAM-1 was detected. The expression of LFA-1, Mac-1, VLA-4 and ICAM-1 on the monocyte cell membrane in patients with an acute myocardial infarction was increased compared with that in control subjects by 22% (on day 7), 67%, 13% and 44% (all on day 4), respectively (all p < 0.001). Elevated density of monocyte-specific CD14 in the AMI versus the control group was also shown (30%, p < 0.001).

CONCLUSIONS

Increased expression of neutrophil and monocyte adhesion molecules may contribute to their adhesion to endothelium in the ischemic territory. This adhesion could feasibly precipitate vasoconstriction or add a local thrombotic effect due to tissue factor expression secondary to Mac-1 engagement. In addition, the manifestation of increased density of LFA-1 and Mac-1 by activated leukocytes with monocytes also expressing ICAM-1 suggests that leukocytes may form microaggregates that could cause microvascular plugging. This mechanism may facilitate the occurrence of the "no-reflow" phenomenon or slow coronary filling after acute myocardial infarction.

Chlamydia pneumoniae antibody response in patients with acute myocardial infarction and their follow-up

STUDY POPULATIONS

This study concerned the possible relations between seroreactivity to Chlamydia pneumoniae and myocardial infarction. A group of 29 patients with acute myocardial infarction (AMI), 74 members of a healthy control group, and a subgroup of 24 members of a healthy control group matched for age, sex, and coronary risk factors (HCM) were included in the study. In addition, we evaluated the AMI group in a 1-year patients' follow-up study. We used two different tests to detect anti-C. pneumoniae antibodies: recombinant enzyme immunoassay antilipopolysaccharide antibodies and a reference microimmunofluorescence test.

RESULTS

High titers of C. pneumoniae microimmunofluorescence antibodies were found in 89.65% of the AMI group and in 25% of the HCM group (p = 0.0000065). Immunoglobulin A-microimmunofluorescence was 51.72% in the AMI group and 20.83% in the HCM group (p = 0.0042). Immunoglobulin G and immunoglobulin A antilipopolysoccharide titers were 65.51% and 62.60% in the AMI group and 20.83% in the HCM group, respectively (p = 0.006). High concentrations of interleukin-6 were found in 86.20% of our AMI group (p value = 54.38 pg/ml) when compared with the control group. A good correlation between interleukin-6 levels and immunoglobulin A-lipopolysaccharide titers (r = 0.658) was found.

CONCLUSION

The presence of a high prevalence rate and high titers of immunoglobulin G and immunoglobulin A-specific anti-C. pneumoniae antibodies in AMI at admission demonstrated the presence of a specific anti-C. pneumoniae immunization in the AMI population.

Inflammatory cytokines impair endothelium-dependent dilatation in human veins in vivo

BACKGROUND

Endothelial dysfunction occurs in many diseases associated with increased cardiovascular risk. We examined the effects of pro-inflammatory cytokines on endothelial function.

METHODS AND RESULTS

Subjects lay with one hand placed on an angled support. The diameter of a vein was recorded by measuring the linear displacement of a probe placed on the skin overlying the vein when the pressure in a congesting cuff placed around the upper arm was deflated from 40 to 0 mm Hg. A length of the vein was isolated by two wedges. TNF-alpha (1 ng), IL-1beta (1 ng), or IL-6 (100 pg) were instilled for 1 hour, either individually or together. At the end of the hour, the wedges were removed and the vein reconnected with the circulation. Dose-response curves (bradykinin: 2, 4, and 8 pmol/min; arachidonic acid: 0.2, 2, and 20 nmol/min; and glyceryl trinitrate 1, 2, and 4 pmol/min) were constructed before and 1, 6, 24, and 48 hours after instillation. In another study, hydrocortisone (100 mg) was given 2 hours before the study. In a different study, subjects were given oral aspirin (75 mg or 1 g) 2 hours before the study. TNF-alpha and IL-1beta alone but not IL-6 attenuated the dilatation to bradykinin and arachidonic acid; the response was greatest at 1 hour with recovery occurring by 6 hours. Combination of IL-1beta and TNF-alpha prolonged the endothelial dysfunction, resulting in recovery at 24 hours. Hydrocortisone and high-dose aspirin prevented endothelial dysfunction.

CONCLUSIONS

The results demonstrate that pro-inflammatory cytokines induce transient and reversible endothelial dysfunction and indicate that cyclooxygenase activity may contribute to the genesis of the effect. If other vessels behave similarly, this may provide further insight into the mechanisms precipitating acute cardiovascular events after inflammatory disorders.