Effect of thrombolytic therapy on platelet expression and plasma concentration of PECAM-1 (CD31) in patients with acute myocardial infarction

Investigation of cardiovascular risk parameters in adolescents with metabolic syndrome

BACKGROUND

Metabolic syndrome leading to type 2 diabetes mellitus and cardiovascular diseases is a chronic multifactorial syndrome, associated with low-grade inflammation status. In our study, we aimed at assessing the serum levels of follistatin (FST), pregnancy-associated plasma protein-A (PAPP-A), and platelet/endothelial cell adhesion molecule-1 (PECAM-1) in adolescent patients with metabolic syndrome.

METHODS

This study was performed in 43 (19 males, 24 females) metabolic syndrome adolescents and 37 lean controls matched for age and sex. The serum levels of FST, PECAM-1, and PAPP-A were measured by using ELISA method.

RESULTS

Serum FST and PAPP-A levels in metabolic syndrome were significantly higher than those of controls (p < 0.005 and p < 0.05). However, there was no difference in serum PECAM-1 levels between metabolic syndrome and control groups (p = 0.927). There was a significant positive correlation between serum FST and triglyceride (r = 0.252; p < 0.05), and PAPP-A and weight, (r = 0.252; p < 0.05) in metabolic syndrome groups. Follistatin was determined statistically significant in both univariate (p = 0,008) and multivariate (p = 0,011) logistic regression analysis.

CONCLUSIONS

Our findings indicated a significant relationship between FST and PAPP-A levels and metabolic syndrome. These findings offer the possibility of using these markers in diagnosis of metabolic syndrome in adolescents as the prevention of the future complications.

Lifetime Evaluation of Left Ventricular Structure and Function in Male C57BL/6J Mice after Gamma and Space-Type Radiation Exposure

The lifetime effects of space irradiation (IR) on left ventricular (LV) function are unknown. The cardiac effects induced by space-type IR, specifically 5-ion simplified galactic cosmic ray simulation (simGCRsim), are yet to be discovered. Three-month-old, age-matched, male C57BL/6J mice were irradiated with 137Cs gamma (γ; 100, 200 cGy) and simGCRsim (50 and 100 cGy). LV function was assessed via transthoracic echocardiography at 14 and 28 days (early), and at 365, 440, and 660 (late) days post IR. We measured the endothelial function marker brain natriuretic peptide in plasma at three late timepoints. We assessed the mRNA expression of the genes involved in cardiac remodeling, fibrosis, inflammation, and calcium handling in LVs harvested at 660 days post IR. All IR groups had impaired global LV systolic function at 14, 28, and 365 days. At 660 days, 50 cGy simGCRsim-IR mice exhibited preserved LV systolic function with altered LV size and mass. At this timepoint, the simGCRsim-IR mice had elevated levels of cardiac fibrosis, inflammation, and hypertrophy markers Tgfβ1, Mcp1, Mmp9, and βmhc, suggesting that space-type IR may induce the cardiac remodeling processes that are commonly associated with diastolic dysfunction. IR groups showing statistical significance were modeled to calculate the Relative Biological Effectiveness (RBE) and Radiation Effects Ratio (RER). The observed dose-response shape did not indicate a lower threshold at these IR doses. A single full-body IR at doses of 100-200 cGy for γ-IR, and 50-100 cGy for simGCRsim-IR decreases the global LV systolic function in WT mice as early as 14 and 28 days after exposure, and at 660 days post IR. Interestingly, there is an intermediate time point (365 days) where the impairment in LV function is observed. These findings do not exclude the possibility of increased acute or degenerative cardiovascular disease risks at lower doses of space-type IR, and/or when combined with other space travel-associated stressors such as microgravity.

Bioinformatic Analysis for Potential Biomarkers and Therapeutic Targets of T2DM-related MI

Background

Type 2 diabetes mellitus (T2DM), a major risk factor of coronary heart disease, is associated with an approximately twofold increase in the risk of myocardial infarction (MI). We studied co-expressed genes to demonstrate relationships between DM and MI and revealed the potential biomarkers and therapeutic targets of T2DM-related MI.

Methods

DM and MI-related differentially expressed genes (DEGs) were identified by bioinformatic analysis, Gene Expression Omnibus (GEO) datasets GSE42148 and GSE61144 of MI patients, and the normal control and GSE26168 and GSE15932 of DM patients and normal controls, respectively. Further target prediction and network analysis method were used to detect protein-protein interaction (PPI) networks, gene ontology (GO) terms, and pathway enrichment of DEGs. Co-expressed DEGs of T2DM-related MI were analyzed as well.

Results

We identified 210 upregulated and 127 downregulated DEGs in T2DM, as well as 264 upregulated and 242 downregulated DEGs in MI. Eighteen upregulated and four downregulated DEGs were identified as co-DEGs of T2DM and MI. Functional analysis revealed that T2DM-related DEGs were mostly enriched in the viral process and ubiquitin-mediated proteolysis, while MI-related DEGs were mostly enriched in protein phosphorylation and TNF signaling pathway. MPO, MMP9, CAMP, LTF, AZU1, DEFA4, STAT3, and PECAM1 were recognized as the hub genes of the co-DEGs with acceptable diagnostic values in T2DM and MI datasets. Adenosine receptor agonist IB-MECA was predicted to be a potential drug for T2DM-related MI with the highest CMap connectivity score.

Conclusion

Our study identified that the co-DEGs of MPO, MMP9, CAMP, LTF, AZU1, DEFA4, STAT3, and PECAM1 are significantly associated with novel biomarkers involved in T2DM-related MI. However, more experimental research and clinical trials are demanded to verify our results.

Myocardial Infarction Superimposed on Aging: MMP-9 Deletion Promotes M2 Macrophage Polarization

In this study, we examined the combined effect of aging and myocardial infarction on left ventricular remodeling, focusing on matrix metalloproteinase (MMP)-9-dependent mechanisms. We enrolled 55 C57BL/6J wild type (WT) and 85 MMP-9 Null (Null) mice of both sexes at 11-36 months of age and evaluated their response at Day 7 post-myocardial infarction. Plasma MMP-9 levels positively linked to age in WT mice (r = .46, p = .001). MMP-9 deletion improved survival (76% for WT vs 88% for Null, p = .021). Post-myocardial infarction, there was a progressive increase in left ventricular dilation with age in WT but not in Null mice. By inflammatory gene array analysis, WT mice showed linear age-dependent increases in three different proinflammatory genes (C3, CCl4, and CX3CL1; all p < .05), whereas Null mice showed increases in three proinflammatory genes (CCL5, CCL9, and CXCL4; all p < .05) and seven anti-inflammatory genes (CCL1, CCL6, CCR1, IL11, IL1r2, IL8rb, and Mif; all p < .05). Compared with WT, macrophages isolated from Null left ventricle infarct demonstrated enhanced expression of anti-inflammatory M2 markers CD163, MRC1, TGF-β1, and YM1 (all p < .05), without affecting proinflammatory M1 markers. In conclusion, MMP-9 deletion stimulated anti-inflammatory polarization of macrophages to attenuate left ventricle dysfunction in the aging post-myocardial infarction.

Association of G+1688A polymorphism of platelet endothelial cell adhesion molecule-1 gene with myocardial infarction in the Chinese Han population

In order to investigate the association of G+1688A (Ser563Asn) polymorphism of platelet endothelial cell adhesion molecule-1 (PECAM-1) gene with myocardial infarction (MI) in the Chinese Han population, the G+1688A polymorphism in PECAM-1 gene was detected by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method among 502 subjects, including 218 patients with MI and 284 controls. The results showed that there was significant difference in AA frequencies of genotype G+1688A polymorphism between case and control groups (39% vs 24%, P<0.001). A similar trend was observed on the allele frequencies (A/G: 62% vs 49%, P<0.001). Among the subjects with high serum total cholesterol level or high systolic blood pressure level, the variant AA genotype was associated with high risk of MI (adjusted OR, 2.13; 95% CI, 1.08-4.41 and adjusted OR, 2.53; 95%CI, 1.63-3.63). The single nucleotide polymorphism (SNP) at position +1688 in the exon 8 of PECAM-1 gene was associated with MI and the allele A might be a risk factor for MI in the Chinese Han population.

Association between platelet endothelial cellular adhesion molecule-1 polymorphisms and atherosclerosis: results of a study on patients from northern Italy

Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leukocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule-1 (PECAM-1), involved in this migration, has been associated with the development of atherosclerosis. Studies have investigated an association between coronary artery disease (CAD) and single-nucleotide polymorphisms (SNPs) located in functionally important domains of the PECAM-1 gene with inconsistent results. Thus, we have analyzed the distribution of V125L, N563S, and G670R SNPs in patients and controls from northern Italy, and also analyzed another functional variant identified in the 5'-untranslated region (UTR) of the PECAM-1 gene (53 G-->A). The polymorphisms of PECAM-1 were genotyped by PCR amplification with sequence-specific primers (PCR-SSP) in 119 controls and 431 CAD patients. Our results demonstrate that genotype and allele frequencies for the 53 G/A polymorphism are significantly different in patients affected by CAD compared to healthy controls, whereas, as regards the V125L and N563S polymorphisms, only the allelic frequency is significantly different. We have shown that there were a significant differences for the 53 G/A and V125L and N563S polymorphisms of PECAM-1 in patients affected by CAD compared to controls. This demonstrates a possible involvement of this gene in contributing to the development of CAD. Therefore, an understanding of the role of the PECAM-1 molecule in this complex mechanism is of pivotal significance in further development of innovative and suitable medical therapies in the future.

Effects of pretreatment with clopidogrel on nonemergent percutaneous coronary intervention after fibrinolytic administration for ST-segment elevation myocardial infarction: a Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis in Myocardial Infarction (CLARITY-TIMI) 28 study

BACKGROUND

The use of routine nonemergent percutaneous coronary intervention (PCI) among patients with ST-segment elevation myocardial infarction (STEMI) after fibrinolytic therapy is unknown. We sought to evaluate the effect of nonemergent PCI on mortality among patients with STEMI treated with fibrinolytic administration and the consequence of clopidogrel pretreatment on this effect.

METHODS

CLARITY-TIMI 28 randomized 3491 patients with STEMI treated with fibrinolytic administration and aspirin to clopidogrel or placebo. All patients were to undergo angiography 48 to 192 hours after randomization. Percutaneous coronary intervention was performed at the discretion of the treating physician. Nonemergent PCI, which was defined as PCI that was not precipitated by recurrent myocardial infarction, was performed in 1781 patients (55.7%).

RESULTS

Nonemergent PCI did not affect 30-day mortality (2.0% vs 2.3% among patients who did not undergo PCI). However, nonemergent PCI was associated with lower mortality among patients randomized to clopidogrel (1.3% vs 2.8%, P = .04) but not among those randomized to placebo (2.6% vs 1.7%, P = .25; interaction P = .025). In multivariate modeling, PCI remained associated with lower mortality among patients randomized to clopidogrel (OR 0.34, 95% CI 0.13-0.92, P = .034) but not placebo (OR 1.41, 95% CI 0.63-3.19, P = .40, interaction P = .028).

CONCLUSION

Among patients with STEMI treated with fibrinolytic administration and aspirin, nonemergent PCI was associated with lower mortality among patients pretreated with clopidogrel. These results suggest that routine nonemergent PCI is beneficial among such patients, although further confirmatory randomized studies are needed.

Intracoronary enalaprilat during angioplasty for acute myocardial infarction: alleviation of postischaemic neurohumoral and inflammatory stress?

AIM

Reperfusion after myocardial ischaemia is associated with a distinct ischaemia/reperfusion injury. Since ACE-inhibition, beyond its influence on cardiac angiotensin II formation and kinin metabolism, has been shown to be cardioprotective by decreasing leucocyte adhesion and endothelin-1 (ET-1) release, we investigated the effects of intracoronary (i.c.) enalaprilat during primary angioplasty in acute myocardial infarction.

METHODS AND RESULTS

Twenty-two patients were randomized to receive i.c. enalaprilat (50 micro g) or placebo immediately after reopening of the infarct-related artery (IRA). Plasma concentrations of soluble L-selectin, P-selectin, intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), ET-1 and nitric oxide metabolite concentrations (NOx) were measured in pulmonary arterial blood. Coronary blood flow was assessed using corrected thrombolysis in myocardial infarction (TIMI) frame counts (CTFC). During reperfusion, there was a significant increase in sL-selectin, sP-selectin and ET-1 in the placebo group, which was greatly diminished by enalaprilat. Levels of sVCAM-1 and sICAM-1 were not affected in either group. CTFC in the placebo group remained higher than normal in both the IRA and nonculprit vessels, whereas myocardial blood flow improved with enalaprilat.

CONCLUSION

Enalaprilat as adjunct to primary angioplasty might be a protective approach to prevent leucocyte adhesion and the release of ET-1, thereby improving coronary blood flow.

Evaluation of markers of endothelial damage in cases of young myocardial infarction

The pathogenesis of arterial thrombotic disease involves multiple genetic and environmental factors related to atherosclerosis and thrombosis. The endothelium is a monolayer of polygonal cells that extend continuously over the luminal surface of the entire vasculature. Injury to the endothelium leads to dysfunction. The causes of injury include lipids, immune complexes, microorganisms, smoking, hypertension, aging, diabetes mellitus and trauma. Studies have been done to evaluate the role of different adhesion molecules on the endothelial membrane in the pathogenesis of atherosclerosis. These molecules are intercellular adhesion molecule type-1 (ICAM-1), vascular cell adhesion molecule type-1 (VCAM-1), platelet/endothelial cell adhesion molecule-1 (PECAM-1), soluble P-selectin (sP-selectin) and soluble E-selectin (sE-selectin). One-hundred and twenty patients of myocardial infarction (age below 40 years) were recruited from the out-patients department of Department of Cardiology, KEM Hospital, Mumbai. All the patients were recruited 8-10 weeks after stabilization after MI. We estimated the levels of sP-selectin, sE-selectin, sPECAM-1 and serum homocysteine. Healthy age and sex-matched controls and family controls were also recruited in the present study. The levels of sP-selectin, sE-selectin and sPECAM-1 did not differ significantly in cases as compared to controls (p>0.05). Hyperhomocysteinemia was significantly associated with MI in comparison with controls (p<0.001) with an odds ratio of 6.26 (95% confidence limits 3.11-12.76). Folic acid was able to correct hyperhomocysteinemia in a large majority of the cases. Although the levels of sP-selectin, sE-selectin and sPECAM-1 decreased after folic acid therapy, it was only sE-selectin which was significantly reduced (p<0.05). Thus, folic acid had a dual effect in that it reduced hyperhomocysteinemia and sE-selectin which showed a significant reduction on folate supplementation for 15 days.

Platelet-endothelial cell adhesion molecule-1 gene polymorphism and its soluble level are associated with severe coronary artery stenosis in Chinese Singaporean

OBJECTIVES

Platelet-endothelial cell adhesion molecule-1 (PECAM-1) mediates the transendothelial migration of circulating leukocytes, a characteristic change in vascular inflammation leading to atherosclerotic plaque development. We hypothesized that genetic variation and soluble level of PECAM-1 could be associated with coronary artery disease (CAD).

DESIGN AND METHODS

We analyzed two single nucleotide polymorphisms (SNPs) of PECAM-1 gene C+373G (Leu125Val) at exon 3, which encodes the first extracellular (Ig)-like domain that mediates the homophilic binding of PECAM-1, and G+1688A (Ser563Asn) at exon 8 in 144 angiographically documented (> or =70% stenosis) patients with CAD and 150 age- and sex-matched controls in the Chinese population in Singapore, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy. Level of plasma soluble PECAM-1 (sPECAM-1) was measured by ELISA.

RESULTS

The Leu125Val polymorphism was associated with CAD (P < 0.01). Also, the level of sPECAM-1 is was found to be elevated in CAD patients (P = 0.005). Moreover, subjects with the homozygous GG genotype of the Leu125Val polymorphism had higher sPECAM-1 levels (P = 0.005). The level of sPECAM-1 was further correlated to soluble platelet selectin (sP-selectin, also measured by ELISA), platelet count, and total white blood cell count (WBC), suggesting that platelets are a major source of sPECAM-1 and platelet activation and inflammation may contribute to PECAM-1 elevations in CAD patients.

CONCLUSION

The Leu125Val polymorphism of PECAM-1 and the level of sPECAM-1 are associated with CAD in Chinese in Singapore. The level of sPECAM-1 is also associated with platelet activation and inflammation and correlated to the Leu125Val polymorphism. Our data suggest that PECAM-1 plays an important role in the development of atherosclerosis.

Preconditioning with sevoflurane decreases PECAM-1 expression and improves one-year cardiovascular outcome in coronary artery bypass graft surgery

BACKGROUND

Cardiac preconditioning is thought to be involved in the observed decreased coronary artery reocclusion rate in patients with angina preceding myocardial infarction. We prospectively examined whether preconditioning by sevoflurane would decrease late cardiac events in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

Seventy-two patients scheduled for elective CABG surgery were randomized to preconditioning by sevoflurane (10 min at 4 vol%) or placebo. For all patients, follow-up of adverse cardiac events was obtained 6 and 12 months after surgery. Transcript levels for platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31), catalase and heat shock protein 70 (Hsp70) were determined in atrial biopsies after sevoflurane preconditioning.

RESULTS

Pharmacological preconditioning by sevoflurane reduced the incidence of late cardiac events during the first year after CABG surgery (sevoflurane 3% vs 17% in the placebo group, log-rank test, P=0.038). One patient in the sevoflurane group and three patients in the placebo group experienced new episodes of congestive heart failure and three additional patients had coronary artery reocclusion. Perioperative peak concentrations for myocardial injury markers were higher in patients with subsequent late cardiac events [NTproBNP, 9031 (4125) vs 3049 (1906) ng litre(-1), P<0.001; cTnT, 1.31 (0.88) vs 0.46 (0.29) microg litre(-1), P<0.001]. Transcript levels were reduced for PECAM-1 and increased for catalase but unchanged for Hsp70 in atrial biopsies after sevoflurane preconditioning.

CONCLUSIONS

This prospective randomized clinical study provides evidence of a protective role for pharmacological preconditioning by sevoflurane in late cardiac events in CABG patients, which may be related to favourable transcriptional changes in pro- and antiprotective proteins.

Increased soluble platelet/endothelial cell adhesion molecule-1 in the early stages of acute coronary syndromes

Specific molecules including inflammatory cell adhesion molecules mediate attachment of blood leukocyte and platelets to the endothelium and mononuclear cell migration into the arterial intima. However, the clinical significance of soluble cell adhesion molecules very early in the course of acute coronary syndrome is not known. We assayed platelet/endothelial cell adhesion molecule-1 (PECAM-1, CD31), intercellular adhesion molecule-1 (ICAM-1, CD54), and P-selectin (CD62P) in plasma obtained from 20 patients within 3 h after the onset of acute myocardial infarction (AMI); 16 patients with unstable angina pectoris; 20 patients with stable angina pectoris, and 28 controls. Blood samples were obtained on hospital admission and again 1 week after onset of AMI and unstable angina, and on admission in patients with stable angina and controls. Plasma PECAM-1 concentration (ng/ml) on admission was higher in patients with AMI (25.6+/-4.7) and unstable angina (24.7+/-4.4) than in stable angina (20.5+/-4.4) and control (18.8+/-3.8) groups. In both AMI and unstable angina, plasma PECAM-1 had decreased significantly by 1 week (AMI, 20.8+/-4.0; unstable angina, 21.0+/-4.1). Plasma ICAM-1 concentration (ng/ml) on admission was higher in patients with AMI (254+/-70), unstable angina (264+/-78), and stable angina (245+/-68) than in controls (201+/-56), but did not differ between the three coronary syndromes. Plasma P-selectin concentration did not differ between the four groups, including controls. Therefore, soluble PECAM-1 concentration may be a sensitive markers providing early diagnostic aid in acute coronary syndromes.

The role of platelet receptors and adhesion molecules in coronary artery disease

Platelets play a significant role in coronary artery disease through interactions with each other and with other cell types. These interactions are mediated by certain receptors on the surface of platelets and other cells which can lead to intra-coronary thrombus formation and occlusion that may result in acute coronary syndromes. The important roles of the currently available anti-platelet therapies have been well established in many clinical outcome trials in cardiovascular patients. An understanding of these different interactions provides the clinician with a background that supports the clinical importance of currently available anti-platelet therapies. Moreover, knowledge of the mechanisms of cellular crosstalk will lead to important advances in the development of better antithrombotic therapies.

Onset and extent of platelet inhibition by clopidogrel loading in patients undergoing elective coronary stenting: the Plavix Reduction Of New Thrombus Occurrence (PRONTO) trial

BACKGROUND

Despite the common practice of clopidogrel loading for coronary stenting, the time dependence and degree of platelet inhibition after this therapy are not well defined. We sought to establish an optimal clopidogrel dosing regimen for sustained platelet inhibition in stented patients.

METHODS AND RESULTS

Platelets were assessed by conventional aggregation with 5 micromol/L adenosine diphosphate (ADP), 1 microg/mL collagen (COLL), and 750 micromol/L arachidonic acid; whole blood aggregation by 1 microg/mL collagen (WBA); shear-induced closure time (CT); contractile force (CF); and expression of 9 surface receptors by flow cytometry in 100 patients undergoing elective stent placement without glycoprotein (GP) IIb/IIIa receptor antagonists. Blood was obtained at baseline and serially over 5 days poststenting after different clopidogrel loading regimens: 300 mg 24 hours before (Group A), 12 hours before (Group B), 3 to 6 hours before (Group C), and 75 mg at the time of intervention (Group D). Before stenting, ADP, COLL, CT, and WBA were reduced by clopidogrel loading (P <.05). CF was not affected by clopidogrel. Before stenting, GP IIb/IIIa expression increased in groups A through C (P <.05), whereas PECAM-1 and CD107a were reduced (P <.05). At 2 hours and 2 days poststenting, platelets, in general, exhibited an increase in activity that was most inhibited by clopidogrel loading. Clopidogrel inhibited GP Ib, platelet/endothelial cell adhesion molecule-1, CD 107a, CD 151, and GP IIb/IIIa expression at day 5 poststenting.

CONCLUSION

A 300 mg clopidogrel load given 3 to 24 hours before stenting inhibits platelets at the time of the procedure and reduces poststent activity more than a 75 mg dose given at the time of the procedure. The inhibition of adhesive molecule expression may also contribute an antithrombotic effect. Poststent activation of platelets may warrant higher periprocedural dosing.

Evaluation of platelets in heart failure: is platelet activity related to etiology, functional class, or clinical outcomes?

OBJECTIVES

We sought to determine whether platelet activity in patients with heart failure is related to an ischemic versus nonischemic etiologic condition, clinical disease severity, or adverse clinical outcomes.

BACKGROUND

Platelet activity may affect outcome in patients with heart failure. A prospective evaluation of the relation of baseline platelet function to etiologic condition, New York Heart Association (NYHA) class, and clinical outcomes has not been previously reported.

METHODS

Ninety-six consecutive outpatients with ambulatory heart failure with an ejection fraction <0.40 and NYHA Class II to IV symptoms who presented to the Duke Heart Failure Clinic and 14 healthy control subjects formed the study groups. Baseline characteristics and blood analyzed for thromboxane (Tx) B2, 6-keto PGF(1alpha), platelet contractile force, adenosine diphosphate/collagen shear-induced closure time, whole blood aggregation and CD41, CD31, CD62p, and CD51/CD61 by flow cytometry were determined. Survival status and hospitalizations were determined in the heart failure patient cohort.

RESULTS

The median age of patients was 65 years (22% female, 64% white). An ischemic etiologic condition was present in 61% of patients. The population had mild to moderate heart failure: NYHA class I (1%), II (41%), III (46%), and IV (12.5%) and severe ventricular dysfunction (median ejection fraction = 0.20). There were 39 clinical events (7 deaths, 3 cardiac transplants, 29 other first hospitalizations) in 305 median days of observation. Platelet activity, indicated by whole blood aggregation with 5 micromol adenosine diphosphate (P =.04) and Tx B2 (P =.01), was higher in patients with heart failure. Whole blood aggregation was greater than the 90th percentile in 22% of patients with heart failure versus 7% of control subjects. Platelet function did not differ for any of the markers between the ischemic and nonischemic groups and was not affected by antecedent aspirin. There was no relation of NYHA class or the occurrence of events to platelet activity.

CONCLUSION

Platelet activity is heightened in 22% of outpatients with stable heart failure symptoms and is not affected by antecedent aspirin therapy. The degree of platelet activation is similar in ischemic and nonischemic patients with heart failure and is not related to clinical disease severity. Current methods to assess platelet activation do not appear to predict outcome.

Adhesion molecules in different treatments of acute myocardial infarction

BACKGROUND

Tissue damage after ischemia and reperfusion involves leukocyte endothelial interactions mediated by cell adhesion molecules. This study was designed to determine the time course of soluble adhesion molecules in patients with acute myocardial infarction after attempted reperfusion by thrombolysis with tissue plasminogen activator (tPA) or streptokinase (SK), or percutaneous transluminal coronary angioplasty (PTCA).

METHODS

In 3 x 10 randomly selected patients with acute myocardial infarction undergoing thrombolysis with tPA or SK, or treated with PTCA, plasma concentrations of soluble L-selectin, P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) were measured by enzyme-linked immunosorbent assay, 30 min and 1, 2, 4, 8, 12 and 24 hours after intervention.

RESULTS

After thrombolysis with tPA, soluble L-selectin concentrations were persistently depressed and soluble PECAM-1 concentrations were elevated, compared with controls, SK and PTCA. While soluble VCAM-1 concentrations did not differ within the first hours after interventions between the three groups, soluble VCAM-1 rose by 24 hours after tPA thrombolysis but did not increase after SK and PTCA treatment. Soluble ICAM-1 concentrations were consistently elevated after PTCA compared with controls and thrombolysed patients. Soluble E-selectin was depressed after tPA thrombolysis and PTCA in comparison with controls, while the SK group showed an increase throughout the observation period. Soluble P-selectin was increased after PTCA and SK lysis up to 8 hours after treatment compared with controls, but no significant differences could be found between treatment groups.

CONCLUSION

Adhesion molecules mediating leukocyte endothelial interactions are altered subsequent to postischemic reperfusion and by treatment with thrombolytic agents and angioplasty. The clinical relevance of these biological changes remains to be determined.

Soluble P-selectin is not a surrogate marker for platelet P-selectin: evidence from a multicenter chest pain study group

It has been reported that platelet expression and plasma levels of soluble P-selectin are increased in patients with unstable coronary artery syndromes. However, the origin of soluble P-selectin remains unknown. We sought to determine whether platelet expression of P-selectin correlates with plasma levels in the population of patients presenting to the emergency department with chest pain. In 338 patients presenting with chest pain to the emergency departments of three different hospitals, simultaneous soluble and platelet P-selection levels were determined using enzyme-linked immunosorbent assay (ELISA) and whole blood flow cytometry, respectively. Using regression analysis no correlation (R(2)=0.055) was found between soluble and platelet-bound P-selectin for the study population, including those patients with noncardiac chest pain (R(2)=0.019), unstable angina (R(2)=0.007), acute myocardial infraction (R(2)=0.033), congestive heart failure (R(2)=0.231), and gastrointestinal illness (R(2)=0.020). The platelet expression of P-selectin is unrelated to the level found in plasma in patients with acute chest pain, irrespective of the etiology of chest pain. Dissociation between platelet and soluble P-selectin suggests that the soluble form cannot serve as a surrogate marker to indicate platelet activation in the chest pain population.

Increased soluble platelet/endothelial cellular adhesion molecule-1 and osteonectin levels in patients with severe congestive heart failure. Independence of disease etiology, and antecedent aspirin therapy

BACKGROUND

Platelet-endothelial interactions modulated by adhesion molecules, may play an important role in the pathogenesis of congestive heart failure (CHF). Soluble levels of these molecules and platelet-derived substances are reportedly elevated in patients with CHF. However, no data are available on the plasma levels of Platelet/Endothelial Cell Adhesion Molecule-1 (PECAM-1), and platelet-derived osteonectin in this growing population.

METHODS AND RESULTS

Soluble levels by ELISA were prospectively determined in patients with severe CHF (n = 37) and correlated to etiology and antecedent aspirin use, and compared with 14 healthy control subjects. Left ventricular dysfunction was attributed to idiopathic dilated cardiomyopathy in 18 and coronary artery disease in 19 patients. Twenty-one patients were aspirin-free and 16 patients were using aspirin (81-500 mg daily). Elevated soluble PECAM-1 (51.31+/-2.44 ng/ml, P = 0.0001), and osteonectin (826.27+/-22.37 ng/ml, P = 0.0001) were observed in patients with CHF, as compared to healthy controls (32.56+/-1.21 ng/ml, and 478.02+/-31.32 ng/ml, respectively). Neither etiology of CHF, nor antecedent aspirin therapy significantly affects the levels of PECAM-1 or osteonectin.

CONCLUSIONS

Despite long-term aspirin therapy and independently of the etiology of the disease, soluble PECAM-1 and osteonectin were elevated in the majority of patients with severe CHF, suggesting platelet-endothelial activation. The present data provide additional evidence that more potent anti-platelet and endothelial preservation regimens deserve further study in the heart failure population.