Assessment of myocardial injury by serum tumour necrosis factor alpha measurements in acute myocardial infarction

Increased Expression of Inactive Rhomboid Protein 2 in Circulating Monocytes after Acute Myocardial Infarction

Increased TNF-α levels following acute myocardial infarction (AMI) contribute to impaired recovery of myocardial function. Interaction of inactive rhomboid protein 2 (iRhom2) with TNF-α converting enzyme (TACE) is required for TNF-α shedding from immune cells. We hypothesized that iRhom2 expression increases in circulating monocytes following AMI. Transcript levels of iRhom2, TACE and TNF-α were evaluated by quantitative real-time PCR in isolated monocytes of 50 AMI patients at admission (d1) and 3 days (d3) after. We observed a significant increase in levels of iRhom2 mRNA expression in monocytes between d1-3, while TNF-α and TACE mRNA expression remained unchanged. At d3, iRhom2 mRNA expression positively correlated with levels of intermediate monocytes or serum TNF-α, and negatively with LV systolic function. iRhom2 may contribute to regulation of post-infarction inflammation and is associated with LV dysfunction following AMI. iRhom2 modulation should be evaluated as a potential therapeutic strategy to attenuate cardiac remodeling following AMI.

Prognostic role of inflammatory cytokines and novel adipokines in acute myocardial infarction: An updated and comprehensive review

Acute myocardial infarction (AMI) is one of the major causes of morbidity and mortality worldwide. The inflammation response during and after AMI is common and seems to play a key role in the peri-AMI period, related with ischaemia-reperfusion injury, adverse cardiac remodelling, infarct size and poor prognosis. In this article, we provide an updated and comprehensive overview of the most important cytokines and adipokines involved in the complex pathophysiology mechanisms in AMI, summarizing their prognostic role post-AMI. Data so far support that elevated levels of the major proinflammatory cytokines TNFα, IL-6 and IL-1 and the adipokines adiponectin, visfatin and resistin, are linked to high mortality and morbidity. In contrary, there is evidence that anti-inflammatory cytokines and adipokines as IL-10, omentin-1 and ghrelin can suppress the AMI-induced inflammatory response and are correlated with better prognosis. Mixed data make unclear the role of the novel adipokines leptin and apelin. After all, imbalance of pro-inflammatory and anti-inflammatory cytokines may result in worst AMI prognosis. The incorporation of these inflammation biomarkers in established prognostic models could further improve their prognostic power improving overall the management of AMI patients.

Identification of Regulatory circRNAs Involved in the Pathogenesis of Acute Myocardial Infarction

Background

Acute myocardial infarction (AMI) has high morbidity and mortality worldwide. However, the pathogenesis of AMI is still unclear, and the impact of circular RNAs (circRNAs) on AMI has rarely been recognized and needs to be explored.

Materials and Methods

The circRNA array was applied to investigate the expression level of circRNAs in the blood samples of coronary arteries of three AMI patients and three normal persons. Principal component analysis (PCA) and unsupervised clustering analysis were performed to reveal the distinguished expression patterns of circRNAs. The miRNA expression profiles of AMI patients were identified from a public dataset from the Gene Expression Omnibus (GEO) database (GSE31568). The miRNA binding sites on the circRNAs were predicted by miRanda. The miRNA enrichment analysis and annotation tool were used to explore the pathways that the dysregulated circRNAs may participate in.

Results

In total, 142 differentially expressed circRNAs, including 89 upregulated and 53 downregulated in AMI samples, were identified by the differential expression analysis. AMI patients had quite different circRNA expression profiles to those of normal controls. Functional characterization revealed that circRNAs that had the potential to regulate miRNAs were mainly involved in seven pathways, such as the Runt-related transcription factor-1 (RUNX1) expression and activity-related pathway. Specifically, hsa_circRNA_001654, hsa_circRNA_091761, hsa_circRNA_405624, and hsa_circRNA_406698 were predicted to sponge four miRNAs including hsa-miR-491-3p, hsa-miR-646, hsa-miR-603, and hsa-miR-922, thereby regulating RUNX1 expression or activity.

Conclusion

We identified dysregulated blood circRNAs in the coronary arteries of AMI patients and predicted that four upregulated circRNAs were involved in the regulation of RUNX1 expression or activity through sponging four miRNAs.

Intravital Microscopy of the Beating Murine Heart to Understand Cardiac Leukocyte Dynamics

Cardiovascular disease is the leading cause of worldwide mortality. Intravital microscopy has provided unprecedented insight into leukocyte biology by enabling the visualization of dynamic responses within living organ systems at the cell-scale. The heart presents a uniquely dynamic microenvironment driven by periodic, synchronous electrical conduction leading to rhythmic contractions of cardiomyocytes, and phasic coronary blood flow. In addition to functions shared throughout the body, immune cells have specific functions in the heart including tissue-resident macrophage-facilitated electrical conduction and rapid monocyte infiltration upon injury. Leukocyte responses to cardiac pathologies, including myocardial infarction and heart failure, have been well-studied using standard techniques, however, certain questions related to spatiotemporal relationships remain unanswered. Intravital imaging techniques could greatly benefit our understanding of the complexities of in vivo leukocyte behavior within cardiac tissue, but these techniques have been challenging to apply. Different approaches have been developed including high frame rate imaging of the beating heart, explantation models, micro-endoscopy, and mechanical stabilization coupled with various acquisition schemes to overcome challenges specific to the heart. The field of cardiac science has only begun to benefit from intravital microscopy techniques. The current focused review presents an overview of leukocyte responses in the heart, recent developments in intravital microscopy for the murine heart, and a discussion of future developments and applications for cardiovascular immunology.

Ischemic preconditioning: Interruption of various disorders

Ischemic heart diseases are the leading cause of morbidity and mortality worldwide. Reperfusion of an ischemic heart is necessary to regain the normal functioning of the heart. However, abrupt reperfusion of an ischemic heart elicits a cascade of adverse events that leads to injury of the myocardium, i.e., ischemia-reperfusion injury. An endogenous powerful strategy to protect the ischemic heart is ischemic preconditioning, in which the myocardium is subjected to short periods of sublethal ischemia and reperfusion before the prolonged ischemic insult. However, it should be noted that the cardioprotective effect of preconditioning is attenuated in some pathological conditions. The aim of this article is to review present knowledge on how menopause and some metabolic disorders such as diabetes and hyperlipidemia affect myocardial ischemic preconditioning and the mechanisms involved.

Interplay Between Inflammation and Hemostasis in Patients with Coronary Artery Disease

Coronary artery disease (CAD) is a global epidemic currently. This study was planned to evaluate markers of inflammation and hemostasis and their possible association, if any, in patients with CAD. The study was carried out in 60 patients with acute myocardial infarction (AMI) and 60 age and gender matched controls. The following parameters were assayed in all study subjects-inflammatory-interleukin (IL)-10, high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, fibrinogen; hemostatic-fibrinogen, fibrin D-dimer and a novel risk factor-homocysteine. Inflammatory markers (hs-CRP, TNF-α and IL-10), fibrinogen, fibrin D-dimer and homocysteine levels were significantly higher in the patients with AMI, as compared with controls. A positive correlation was observed between D-dimer and the inflammatory markers-hs-CRP and TNF-α. Upon multivariate analysis, TNF-α emerged as the best determinant of CAD in our study. Our results indicate that there is a possible interplay of inflammation and hemostasis in CAD, underlining their synergistic role in the pathogenesis of CAD.

WISP1, a pro-mitogenic, pro-survival factor, mediates tumor necrosis factor-alpha (TNF-alpha)-stimulated cardiac fibroblast proliferation but inhibits TNF-alpha-induced cardiomyocyte death

WNT1-inducible signaling pathway protein-1 (WISP1), a member of the CYR61/CTGF/Nov family of growth factors, can mediate cell growth, transformation, and survival. Previously we demonstrated that WISP1 is up-regulated in post-infarct heart, stimulates cardiac fibroblast proliferation, and is induced by the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). Here we investigated (i) the localization of TNF-alpha and WISP1 in post-infarct heart, (ii) the mechanism of TNF-alpha-mediated WISP1 induction in primary human cardiac fibroblasts (CF), (iii) the role of WISP1 in TNF-alpha-mediated CF proliferation and collagen production, and (iv) the effects of WISP1 on TNF-alpha-mediated cardiomyocyte death. TNF-alpha and WISP1 expressions were increased in the border zones and non-ischemic remote regions of the post-ischemic heart. In CF, TNF-alpha potently induced WISP1 expression in cyclic AMP response element-binding protein (CREB)-dependent manner. TNF-alpha induced CREB phosphorylation in vitro and DNA binding and reporter gene activities in vivo. TNF-alpha induced CREB activation via ERK1/2, and inhibition of ERK1/2 and CREB blunted TNF-alpha-mediated WISP1 induction. Most importantly, WISP1 knockdown attenuated TNF-alpha stimulated collagen production and CF proliferation. Furthermore, WISP1 attenuated TNF-alpha-mediated cardiomyocyte death, thus demonstrating pro-mitogenic and pro-survival effects for WISP1 in myocardial constituent cells. Our results suggest that a TNF-alpha/WISP1 signaling pathway may contribute to post-infarct cardiac remodeling, a condition characterized by fibrosis and progressive cardiomyocyte loss.

Relationship of admission neutrophil count to microvascular injury, left ventricular dilation, and long-term outcome in patients treated with primary angioplasty for acute myocardial infarction

BACKGROUND

The relationship of admission neutrophil count to the degree of microvascular injury, left ventricular (LV) volume, and long-term outcome after acute myocardial infarction (AMI) was examined in the present study.

METHODS AND RESULTS

The study group comprised 228 consecutive patients with a first anterior wall AMI who underwent primary angioplasty within 12 h of onset. The degree of microvascular injury was evaluated by Doppler guidewire. Adverse cardiac events were recorded during an average follow-up of 52+/-28 months. Using a receiver-operating characteristic analysis, a neutrophil count >or=7,260 cells/mm(3) was the best predictor of future cardiac events. By regression analysis, the neutrophil count significantly correlated with diastolic deceleration time (r=-0.40, p<0.0001), coronary flow reserve (r=-0.43, p<0.0001), and LV end-diastolic volume at 4 weeks (r=0.32, p<0.0001). Kaplan-Meier survival analysis showed a higher incidence of adverse cardiac events in patients with a high neutrophil count (p=0.002). By multivariate analysis, a neutrophil count >or=7,260 cells/mm(3) was an independent predictor of long-term adverse cardiac events (odds ratio 3.8, p=0.002).

CONCLUSION

Neutrophilia on admission is associated with impaired microvascular perfusion, LV dilation, and long-term adverse cardiac events in patients treated with primary angioplasty for AMI.

[Prognostic value of tumor necrosis factor-alpha in patients with ST-segment elevation acute myocardial infarction]

INTRODUCTION AND OBJECTIVES

Tumor necrosis factor-alpha (TNFalpha in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to determine the prognostic value of TNFalpha in this clinical setting at six-month follow-up.

METHODS

The levels of TNFalpha, C-reactive protein (CRP), interleukin 6 and type 1 soluble intercellular adhesion molecules measured within the first 10 h of symptom onset and at 48 h in 74 consecutive patients admitted with STEMI. The relationships between these levels and the incidence of ischemic events (i.e., angina, reinfarction, and death), heart failure (HF), or both (i.e., all cardiovascular events) were studied.

RESULTS

Overall, TNFalpha levels were significantly higher in patients who had an ischemic event or HF than in those who did not (P<.02 for both). At 48 h, the adjusted odds ratios of those in the highest TNFalpha quartile (2.92 pg/mL) for the development of ischemic events, HF, and all cardiovascular events combined were 13.1, 9.59 and 9.75, respectively. A TNFalpha level of 2.04 pg/mL at 48 h had a sensitivity of 78% and a specificity of 72.5% in predicting a cardiovascular event of any form. The CRP level, but not the TNFalpha level, at admission was found to be an independent predictor of the development of a cardiovascular events.

CONCLUSIONS

In patients with STEMI, the plasma TNFalpha level 48 h after symptom onset and the CRP level at admission were independent predictors of cardiovascular events.

Serum interferon-gamma-inducible protein 10 level was increased in myocardial infarction patients, and negatively correlated with infarct size

OBJECTIVES

We examined the serum levels of interferon-gamma-inducible protein 10 (IP-10), an inflammation-induced chemokine, in acute myocardial infarction (AMI).

DESIGN AND METHODS

The subjects were 33 AMI patients, 20 stable angina pectoris patients (AP) and 20 normal subjects. In AMI patients, blood samples were collected before percutaneous coronary intervention (PCI) and on days 3, 7 and 28.

RESULTS

Patients with AMI showed significantly higher serum IP-10 levels (137.5+/-79.8 pg/mL) than control subjects (91.2+/-40.1 pg/mL) and patients with AP (93.3+/-41.1 pg/mL). The serum IP-10 level before PCI was negatively correlated with infarct size, as indicated by cumulative release of creatine kinase (CK) and peak CK and its isoenzyme CK-MB. Stepwise multiple regression analysis revealed that the serum IP-10 level before PCI was an independent predictor of cumulative CK release.

CONCLUSIONS

The serum IP-10 level was increased in AMI, and a higher level of serum IP-10 before PCI may be informative regarding infarct size.

Relation between neutrophil counts on admission, microvascular injury, and left ventricular functional recovery in patients with an anterior wall first acute myocardial infarction treated with primary coronary angioplasty

Increased neutrophil counts have been associated with an increased risk of adverse clinical events after acute myocardial infarction (AMI). We examined the association of neutrophil counts on admission with degree of microvascular injury and left ventricular functional recovery after primary coronary angioplasty in AMI. We studied 116 patients with a first anterior wall AMI who underwent primary coronary angioplasty within 12 hours of onset. Patients were categorized into 3 groups based on initial neutrophil count: low (<5,000/mm(3)), intermediate (5,000 to 10,000/mm(3)), and high (>10,000/mm(3)). Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. We defined severe microvascular injury as the presence of systolic flow reversal and a diastolic deceleration time <600 ms. Echocardiographic wall motion was analyzed before revascularization and 4 weeks after revascularization. In patients with a high neutrophil count, systolic flow reversal was more frequently observed, diastolic deceleration time was shorter, and coronary flow reserve was lower. By regression analysis, neutrophil count significantly correlated with diastolic deceleration time (r = -0.38, p <0.0001), coronary flow reserve (r = -0.33, p = 0.0004), and score for change in wall motion (r = -0.36, p = 0.0004). Multivariate analysis showed that neutrophil count on admission was an independent predictor of severe microvascular injury (odds ratio 2.94, p = 0.02). In conclusion, neutrophilia on admission is associated with impaired microvascular reperfusion and poor functional recovery after primary coronary angioplasty.

Preconditioning: Gender Effects1

Preconditioning is injury induced protection from subsequent injury. During preconditioning protective cellular responses to injury are up regulated resulting in acute and delayed defense against further damage. Several studies indicate that females experience a protective advantage after acute insult compared to males. Despite evidence of gender differences in acute injury, relatively few studies have evaluated whether there are sex differences in preconditioning. Variations in patients' pre-morbid preconditioning status may explain outcome variations that are not apparent in small animal studies. This review discusses the differences in response to acute injury experienced by males and females, the basic mechanisms of preconditioning, and the sex differences in the mechanisms of preconditioning.

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.

Tumour necrosis factor-alpha and interleukin-6 release during primary percutaneous coronary intervention for acute myocardial infarction is related to coronary collateral flow

OBJECTIVES

We tested the hypothesis that there was an association between tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) release and measured coronary collateral flow in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI).

BACKGROUND

Tumour necrosis factor-alpha and IL-6 increase during acute myocardial infarction (AMI). However, their relation to coronary collateral flow is unknown.

METHODS

Twelve patients with AMI due to complete thrombotic coronary occlusion underwent primary PCI within 12 h of symptom onset. Doppler-derived collateral flow index (CFI) was measured during first balloon inflation. TNF-alpha, IL-6, creatine kinase (CK), CK-MB fraction were measured from venous plasma samples serially for 24 h. Area at risk was determined off-line by coronary arteriography. Ejection fraction (EF) was measured using biplane left ventricular angiography.

RESULTS

Maximal CK release varied between 569 and 6276 U/l and area at risk varied between 7 and 47% of myocardium. Tumour necrosis factor-alpha (peak 4.4+/-0.5 pg/ml) and IL-6 (peak 35.5+/-3.0 pg/ml) increased in all patients. Peak TNF-alpha and IL-6 release was independent of CK, CKMB. No minimal threshold of myocardial necrosis for cytokine expression could be detected. Similarly, TNF-alpha and IL-6 release was also independent of time to reperfusion, area at risk or EF. Using univariate regression analysis, peak TNF-alpha inversely correlated with CFI (r = 0.67, P = 0.017) whereas IL-6 positively correlated with CFI (r = 0.76, P = 0.004).

CONCLUSIONS

Acute myocardial infarction is associated with a significant rise in TNF-alpha and IL-6 levels independent of infarct size or myonecrosis. Tumour necrosis factor-alpha and IL-6 correlate dichotomously with CFI indicating differing roles in reperfused AMI.

The dilemma of the strive for apoptosis in oncology: mind the heart

In recent years, apoptosis has increasingly drawn the attention of both oncologists and cardiologists alike. Anticancer treatment is possible by induction of apoptosis in cancer cells, and targeted anticancer drugs are being developed to promote this. However, since these drugs usually are not selective for malignant cells, side effects on non-cancerous tissue, such as the myocardium must be anticipated. Since apoptosis is a pathophysiological mechanism in cardiac diseases leading to heart failure, cardiologists in contrast to oncologists, aim at preventing apoptosis in the heart. The purpose of this review is to describe new insights in mechanisms of cardiomyocyte apoptosis. In addition to the mitochondrial and death receptor apoptotic pathways, apoptosis through lack or inhibition of growth factor receptor-mediated signalling is discussed. Exploration of the apoptotic pathways in the heart can contribute to the safer use of new anticancer drugs and to the development of new therapies for heart failure.

Serum tumour necrosis factor-alpha, interleukin-2 and interleukin-10 activation in stable angina and acute coronary syndromes

BACKGROUND

Dynamic instability of coronary atherosclerotic plaque results in the development of both unstable angina and myocardial infarction. The aim of the study was to investigate the dynamics of serum concentrations of tumour necrosis factor (TNF)alpha, interleukin (IL)-10, and IL-2 in patients with myocardial infarction (MI) and unstable angina (UA) as compared to stable angina (SA) patients and healthy volunteers.

METHODS

A total of 189 patients with coronary artery disease (CAD) were studied: 100 patients with SA (class II/III according to CCS), 57 patients with UA (Braunwald class IIIB; determinations at 6, 24, and 48 h after chest pain), and 32 patients with MI (determinations at admission, on the 7th and 30th days after MI). Twenty healthy volunteers acted as controls.

RESULTS

Serum TNFalpha levels were elevated in all CAD groups (SA: 17.3+/-4; UA: 18.7+/-4; MI: 22.0+/-3 pg/ml; p<0.001) in comparison to the controls (8.3+/-1.4 pg/ml). However, the highest values were characteristic of MI patients, especially values obtained at admission (p<0.01 versus SA and UA). Mean serum concentrations of IL-2 were significantly higher in patients with MI and UA (89.6+/-40; 87.0+/-24 pg/ml, respectively; p<0.01) when compared to SA and the control group (58.3+/-49; and 51.5+/-39, respectively). Serum IL-10 levels were also higher in MI and UA patients. Levels of IL-2 and IL-10 measured following chest pain in unstable patients, as well as their consecutive determinations in MI patients did not show any change dynamics, that is, they were persistently elevated.

CONCLUSIONS

When compared to stable CAD and healthy subjects, acute coronary syndromes are associated with long-term increase of serum concentrations of pro- and anti-inflammatory cytokines. It seems likely that sudden CAD progression leading to acute coronary syndromes is triggered/accompanied by prolonged immune activation.

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.

Endogenous cannabinoids mediate hypotension after experimental myocardial infarction

OBJECTIVES

We sought to determine whether endocannabinoids influence hemodynamic variables in experimental models of acute myocardial infarction (MI).

BACKGROUND

Hypotension and cardiogenic shock are common complications in acute MI. Cannabinoids are strong vasodilators, and endocannabinoids are involved in hypotension in hemorrhagic and septic shock.

METHODS

The early effect of left coronary artery ligation on hemodynamic variables was measured in rats pretreated with the selective cannabinoid(1) receptor (CB(1)) antagonist SR141716A (herein referred to as SR, 6.45 micromol/kg body weight intravenously) or vehicle. Endocannabinoids produced in monocytes and platelets were quantified by liquid chromatography/mass spectrometry (LC/MS), and their effects on blood pressure and vascular reactivity were determined.

RESULTS

After MI, mean arterial pressure (MAP) dropped from 126 +/- 2 mm Hg to 76 +/- 3 mm Hg in control rats, whereas the decline in blood pressure was smaller (from 121 +/- 3 mm Hg to 108 +/- 7 mm Hg, p < 0.01) in rats pretreated with SR. SR increased the tachycardia that follows MI (change [Delta] in heart rate [HR] = 107 +/- 21 beats/min vs. 49 +/- 9 beats/min in control rats, p < 0.05). The MI sizes were the same in control rats and SR-treated rats. Circulating monocytes and platelets isolated 30 min after MI only decreased MAP when injected into untreated rats (DeltaMAP = -20 +/- 5 mm Hg), but not in SR-pretreated rats. The endocannabinoids anandamide and 2-arachidonyl glycerol were detected in monocytes and platelets isolated after MI, but not in cells from sham rats. Survival rates at 2 h after MI were 70% for control rats and 36% for SR-treated rats (p < 0.05). Endothelium-dependent arterial relaxation was attenuated in SR-treated rats (maximal relaxation: 44 +/- 3% [p < 0.01] vs. 70 +/- 3% in control rats) and further depressed by SR treatment (24 +/- 5%, p < 0.01 vs. MI placebo).

CONCLUSIONS

Cannabinoids generated in monocytes and platelets contribute to hypotension in acute MI. Cannabinoid(1) receptor blockade restores MAP but increases 2-h mortality, possibly by impairing endothelial function.

Investigation of human spleen dendritic cell phenotype and distribution reveals evidence of in vivo activation in a subset of organ donors

Although the mouse spleen dendritic cell (DC) is perhaps the most intensively studied DC type, little has been published concerning its human equivalent. In this report, rare event flow cytometry and in situ immunofluorescence were used to study the surface phenotype and distribution of HLA-DR(+) CD3(-)14(-)16(-)19(-) human spleen DC. Spleens from organ donors with different clinical histories were used. Most (81% +/- 9%; n = 14) spleen DCs expressed high levels of the integrin CD11c. CD11c(+) DCs were distributed in 3 distinct regions-the peri-arteriolar T-cell zones, the B-cell zones, and the marginal zone, where they formed a ring of cells surrounding the white pulp, just inside a ring of CD14(+) red pulp macrophages, apparently more regularly organized than the previously described marginating DC population in the mouse spleen. The T-cell zones contained CD86(+) DCs, among which a subpopulation expressed CD83. These mature/activated CD86(+) DCs represented a minority (12% +/- 8%) of total spleen DCs in most organ donors: most spleen DCs are immature. In 3 of 18 (17%) donors, however, most (54%-81%) of spleen DCs were CD86(+), suggesting that in vivo DC activation had occurred. In one donor, a radical shift in DC distribution from the marginal zone to the T-cell zones was also observed. This activation of spleen DCs in vivo was reminiscent of the effects of experimental microbial product injection in mice, and it seemed to correlate with bacterial infection or multiple trauma. (Blood. 2001;97:3470-3477)

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Isoproterenol Inhibits Bacterial Lipopolysaccharide-Stimulated Release of Tumor Necrosis Factor-α from Human Heart Tissue

Recent evidence suggests that inflammatory cytokines, particularly tumor necrosis factor a (TNF-α), may play a role in heart disease. Elevated plasma levels of the cytokine have been reported in congestive heart failure and severe angina and after myocardial infarction. The exact role of TNF-α in heart disease and how production is stimulated and regulated in the heart are current areas of investigation. Regarding regulation of production, isoproterenol elevates cyclic AMP and inhibits TNF-α release in macrophages. Therefore we hypothesized that stimulation of β-adrenergic receptors of the sympathetic nervous system would inhibit release of the cytokine from heart tissue. With Institutional Review Board approval and patient consent atrial tissue was obtained during preparation for cardiac bypass. The tissue was divided into segments, placed in culture medium, and incubated for various times in the presence or absence of lipopolysaccharide (LPS) (20 μg/mL) and/or isoproterenol (1 μM). The medium was removed and analyzed for biologically active TNF-α by the L929 cell cytotoxicity assay. Tissue samples were weighed and TNF-α release was expressed as pg TNF-α/mg tissue. Initially, to determine the time course of release, measurements were made at 2, 5, 10, 15, 30, 60, 120, 180, and 360 minutes after the addition of LPS. Elevated TNF-α levels in the culture medium were reliably detected at 360 minutes after exposure to LPS. In atrial tissue obtained from seven patients TNF-α released into the culture medium at 360 minutes was 6 ± 3 pg/mg tissue. In the presence of LPS, levels of the cytokine in the culture medium increased to 604 ± 233 pg/mg tissue ( P < 0.05 vs LPS alone). When isoproterenol and LPS were simultaneously added to the culture medium release of TNF-α was reduced by 87 per cent to 82 ± 40 pg/mg tissue ( P < 0.05 vs LPS alone). Our results show that activation of the β-adrenergic receptor inhibits myocardial production of TNF-α. This finding suggests that the sympathetic nervous system inhibits production of the cytokine and that impaired sympathetic function in heart failure may play a role in the elevated levels of TNF-α.

Neutrophilia and congestive heart failure after acute myocardial infarction

BACKGROUND

Inflammation associated with acute myocardial infarction (AMI) is frequently marked by a peripheral leukocytosis and relative neutrophilia. Whether this process may contribute to the development of postinfarction congestive heart failure (CHF) is not established. The objective of this study was to examine the association between hospital admission peripheral total leukocyte count and the neutrophil percentage and the subsequent development of CHF in patients with AMI. The study was designed as a retrospective cohort study in the setting of a tertiary referral hospital. Participants included 185 patients discharged with a diagnosis of AMI between May 1 and Sept 30, 1996.

METHODS AND RESULTS

Outcome measures included clinical episodes of CHF with confirmatory chest roentgenogram findings and/or echocardiographic evidence of contractile dysfunction. Multivariable logistic regression analyses were performed to examine the relation between the total leukocyte count, neutrophil percentage, and the development of CHF in the first 4 days after AMI while controlling for baseline characteristics and early therapeutic interventions. Thirty-one percent of the cohort had a leukocyte count >11.0 x10(9)/L on admission to the hospital; 65% had a neutrophil percentage >65%, and 61% had a lymphocyte percentage </=25%. CHF developed in 43% of the cohort. Of these, 92. 5% had relative neutrophilia (neutrophil percentage >65%) compared with 45% of those in whom CHF did not develop. Multivariable analysis revealed a highly significant association between relative neutrophilia and the subsequent development of CHF (odds ratio 14.3; 95% confidence interval 5.2 to 39.3).

CONCLUSIONS

Relative neutrophilia on admission to the hospital in patients with AMI is significantly associated with the early development of CHF. This association may help in the identification of individuals at high risk who might benefit from more aggressive interventions to prevent or reduce the risk of CHF.

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.

Plasma adrenomedullin as an indicator of prognosis after acute myocardial infarction

OBJECTIVE

To elucidate whether prognosis after acute myocardial infarction can be predicted by measuring plasma adrenomedullin, a novel vasorelaxant peptide.

PATIENTS AND DESIGN

Plasma adrenomedullin concentrations on day 2 after myocardial infarction were measured in 113 patients with myocardial infarction with other clinical and haemodynamic variables related to mortality.

RESULTS

During a mean follow up period of 25 months, 16 patients died of cardiac causes. Plasma adrenomedullin concentrations on day 2 increased significantly in patients with myocardial infarction compared with controls (mean (SD), 12.3 (8.8) v 4.9 (1.0) pmol/l, p < 0.001). Plasma adrenomedullin correlated negatively with left ventricular ejection fraction on admission (r = -0.47, p < 0.001), although it did not significantly correlate with any other haemodynamic variable. By univariate Cox proportional hazards analysis, plasma adrenomedullin, age, coronary reperfusion, maximum creatine kinase concentrations, pulmonary congestion, pulmonary capillary wedge pressure, cardiac index, and left ventricular ejection fraction were all significantly related to mortality. Among the non-invasive variables, only plasma adrenomedullin was an independent predictor of mortality after myocardial infarction (p < 0.05). The Kaplan-Meier survival curves based on the median plasma adrenomedullin concentration (10.3 pmol/l) showed that patients with high plasma adrenomedullin had a higher mortality than those with low plasma adrenomedullin (p < 0.01).

CONCLUSIONS

Plasma adrenomedullin on day 2 after myocardial infarction is strongly associated with long term mortality, and thus may complement standard prognostic indicators.

Tissue expression and immunolocalization of tumor necrosis factor-alpha in postinfarction dysfunctional myocardium

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is markedly elevated in advanced heart failure. It is not known whether tissue TNF-alpha is elevated in the common setting of myocardial infarction leading to heart failure and what the source of TNF-alpha is. To determine this, we studied the expression and protein localization of TNF-alpha and its 2 main receptors (TNF-R1/R2) in a rat model of large infarction.

METHODS AND RESULTS

Male rats were randomized to proximal left anterior descending ligation. The animals were killed on days 1, 3, 10, and 35 after ligation to examine gene expression and protein production of TNF-alpha and TNF-R1/R2 from the infarct, peri-infarct, and contralateral zones of infarcted heart. There was increased TNF-alpha mRNA production throughout the myocardium at day 1, and detectable expression persisted to day 35 after myocardial infarction. The expression of this cytokine is not confined strictly to the infarct or peri-infarct zones but is expressed by cardiac myocytes within the myocardium in the contralateral normal zone. Changes in gene expression are mirrored initially by augmented protein production within the myocytes. Levels of TNF-alpha protein in the infarct and peri-infarct zones rose early to 8- to 10-fold above normal levels and rose to 4- to 5-fold in the contralateral zone. Finally, expression of the TNF-R1 mRNA transcripts was upregulated at days 3 and 10 after ligation in the infarct and peri-infarct zones, suggesting that the signal transduction pathways necessary for TNF-alpha in the heart remain intact as TNF-alpha biosynthesis increases.

CONCLUSIONS

TNF-alpha is present early in a model of large myocardial infarction and is sustained into the later stage within the myocardium. Expression of this cytokine is not only confined strictly to the infarct or peri-infarct zone but is expressed by cardiac myocytes within the myocardium contralateral to the infarct. Therefore TNF-alpha production forms a part of an important intrinsic myocardial stress response system to injury.

Cardiac myocytes produce interleukin-6 in culture and in viable border zone of reperfused infarctions

BACKGROUND

Previous work from our laboratory demonstrated that interleukin (IL)-6 plays a potentially critical role in postreperfusion myocardial injury and is the major cytokine responsible for induction of intracellular adhesion molecule (ICAM)-1 on cardiac myocytes during reperfusion. Myocyte ICAM-1 induction is necessary for neutrophil-associated myocyte injury. We have previously demonstrated the induction of IL-6 in the ischemic myocardium, and the current study addresses the cells of origin of IL-6.

METHODS AND RESULTS

In the present study, we combined Northern blot analysis and in situ hybridization to demonstrate IL-6 gene expression in cardiac myocytes. Isolated ventricular myocytes were stimulated with tumor necrosis factor-alpha, IL-1beta, lipopolysaccharide, preischemic lymph, and postischemic lymph. Unstimulated myocytes showed no significant IL-6 mRNA expression. Myocytes stimulated with preischemic lymph showed minimal or no IL-6 mRNA expression, whereas myocytes stimulated with tumor necrosis factor-alpha, IL-1beta, lipopolysaccharide, or postischemic lymph showed a strong IL-6 mRNA induction. Northern blot with ICAM-1 probe revealed ICAM-1 expression under every condition that demonstrated IL-6 induction. We then investigated the expression of IL-6 mRNA in our canine model of ischemia and reperfusion. Cardiac myocytes in the viable border zone of a myocardial infarction exhibited reperfusion-dependent expression of IL-6 mRNA within 1 hour after reperfusion. Mononuclear cells infiltrate the border zone and express IL-6 mRNA.

CONCLUSIONS

Isolated cardiac myocytes produce IL-6 mRNA in response to several cytokines as well as postischemic cardiac lymph. In addition to its production by inflammatory cells, we demonstrate that IL-6 mRNA is induced in myocytes in the viable border zone of a myocardial infarct. The potential roles of IL-6 in cardiac myocytes in an infarct border are discussed.

Prediction of early complications in patients with acute myocardial infarction by calculation of the ST score

STUDY OBJECTIVE

To assess the relationship between the sum of ST-segment elevations (ST score) in the admission ECG and the occurrence of early complications in patients with acute myocardial infarction (MI).

METHODS

We conducted an observational study of patients who presented with acute anterior or inferior MI to the ED of a 2,000-bed inner-city hospital. Age, sex, time from onset of pain and the start of thrombolysis, and ST score were evaluated by the emergency physician. "Early complications" were defined as acute congestive heart failure or severe rhythm disturbances in the 24 hours after the start of thrombolysis. The outcome measures were the relationship between ST score and the occurrence of early complications; the influence of age, sex, or time between onset of pain and thrombolysis; and identification of a cutoff value with the highest sensitivity and specificity for prediction of complications.

RESULTS

We included 243 patients (194 men, 49 women; mean age, 56.6 years) with acute MI (anterior, 119; inferior, 124) who underwent thrombolysis in our analysis. ST score was significantly greater in patients with early complications, compared with patients without complications (anterior, 10.3 versus 19.4 mm [P < .001]; inferior, 6.9 versus 10.4 mm [P < .001]). Receiver-operator curve analysis revealed an ST score of 13 mm in patients with anterior MI and 9 mm in patients with inferior MI as the cutoff value with the greatest sensitivity and specificity for predicting early complications of MI. (For anterior MI, sensitivity was .79, specificity .73; for inferior MI, sensitivity was .64 and specificity .68.). On multivariate regression analysis, ST score was an independent predictor of the occurrence of at least one complication. (For anterior MI, the odds ratio [OR] was 9.7 and the 95% confidence interval [CI] 3.9 to 25.1; for inferior MI the OR was 5.0 and the 95% CI 2.0 to 12.8). Age, sex, and interval from onset of pain to treatment had no significant effect on the occurrence of early complications.

CONCLUSION

The absolute ST score is useful in estimating the probability of early complications in patients with acute MI receiving thrombolytic therapy. A cutoff value of 13 mm for anterior MI and 9 mm for inferior MI stratifies patients into high- and low-risk subgroups for the development of acute congestive heart failure and severe rhythm disturbances during the first 24 hours of hospitalization.