Luciana Tomasi

Hydroxymethyl-Glutaryl Coenzyme A Reductase Inhibition Limits Cytomegalovirus Infection in Human Endothelial Cells

Background—Statins exert anti-inflammatory effects independently of cholesterol-lowering properties. Cytomegalovirus (CMV) infection appears to be implicated in the pathophysiology of atherosclerosis by inducing inflammatory modifications in endothelial cells, especially in immunosuppressed patients. We investigated whether the activity of statins can inhibit replication of CMV in human endothelial cells. Methods and Results—Human umbilical vein endothelial cells (HUVECs) were infected with CMV and coincubated with fluvastatin at 0.1 and 0.2 &mgr;mol/L. Fluvastatin inhibited (P <0.001) CMV antigen expression, and this effect was dose related (P <0.001). Quantitative polymerase chain reaction showed that CMV DNA concentration was consistently lower in supernatants from fluvastatin-treated cells than in infected controls, and viral particle concentration was up to 30 times lower in 0.2 &mgr;mol/L fluvastatin-treated cells than in infected controls (10.5±0.9 versus 0.34±0.03 per 103 pfu/mL, P <0.001). Addition of mevalonate to treated cultures almost completely abolished fluvastatin inhibition of viral growth. Electrophoretic mobility shift assay showed that fluvastatin reduced nuclear factor-&kgr;B binding activity in CMV-infected cells. Conclusions—HMG-CoA inhibition by fluvastatin restrains CMV replication in HUVECs by inhibiting viral antigen expression, DNA synthesis, and viral particle production, conceivably by involving a reduction of nuclear factor-&kgr;B binding activity.

A randomised study comparing the antiplatelet and antinflammatory effect of clopidogrel 150 mg/day versus 75 mg/day in patients with ST-segment elevation acute myocardial infarction and poor responsiveness to clopidogrel: Results from the DOUBLE study

INTRODUCTION The antiplatelet effect of standard or increased clopidogrel doses in patients with ST- segment elevation acute myocardial infarction (STEMI) has never been studied. In this study we compared the antiplatelet effect of a 75 mg daily maintenance dose of clopidogrel with 150 mg in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). MATERIALS AND METHODS Fifty-four patients with STEMI undergoing PCI were randomly allocated to receive either 75 mg/day clopidogrel (group 1) or 150 mg/day (group 2) for 1 month. Platelet function, measured by 5 different assays, was determined at 3 time points: 38+/-8 hours after the procedure, 1 week and 1 month after randomization. RESULTS In group 1, mean +/- SD platelet reactivity index (PRI) measured with the VASP assay was 57.7+/-15.7% and 46.9+/-15.7% at 1 week and 1 month, respectively, compared to 38.8+/-15.7% and 34.9+/-12.6% in group 2 (p=0.0001). Same results were observed for light transmittance aggregometry, whole blood aggregometry and VerifyNow, but not for thromboelastometry. In contrast to what may be expected, the 75 mg daily maintenance dose took longer than 1-week to provide the full clopidogrel antiplatelet effect. Furthermore, patients in group 2 had a nearly 50% reduction in C-reactive protein levels both at 1 week and 1 month. CONCLUSION In patients with STEMI and poor responsiveness to clopidogrel a 150 mg daily maintenance dose of clopidogrel is associated with a significant reduction of platelet aggregation and a trend towards reduced inflammation.

Minimal effective concentration values of propafenone and 5-hydroxy-propafenone in acute and chronic therapy

SummaryWe evaluated the antiarrhythmic efficacy and the minimal effective concentrations of propafenone and its metabolite 5-hydroxy-propafenone during a) acute intravenous infusion (1.5 mg/kg in bolus followed by 45 minutes infusion), b) an acute oral single-dose test (450 mg), and c) 14-day chronic therapy (300 mg tid) followed by a washout. Oxidative metabolism was assessed by a debrisoquine oral test in every patient. Eleven patients with stable ventricular premature beats (VPBs)≥300/hr and Lown class ≥ 3 completed the study. The main results emphasized a certain discrepancy between the clinical effect of the acute intravenous infusion (efficacy in 5 out of 11 patients) and of the acute oral test and chronic therapy (efficacy in 11/11), with a time lag of the ECG changes during the acute intravenous infusion. The minimal effective concentrations were lower after acute oral administration compared with chronic treatment both for propafenone (200±189 ng/ml vs. 492±530 ng/ml; p<0.05) and for 5-hydroxy-propafenone (82±40 ng/ml vs. 149±80 ng/ml; p<0.02). A linear correlation was demonstrated between drug/metabolite ratios of propafenone and debrisoquine, either after acute oral (r=0.91) or after chronic administration (r=0.84). The pharmacokinetics of propafenone was nonlinear and showed wide interindividual variations. In conclusion, a) the lower efficacy and delayed electrophysiologic effects of propafenone after intravenous administration suggest that longer infusion times are necessary for complete antiarrhythmic efficacy; b) the differences observed in the minimal effective concentrations of acute versus chronic oral therapy suggest the development of partial tolerance to propafenone during chronic treatment.

Detection of Tissue Factor Antigen and Coagulation Activity in Coronary Artery Thrombi Isolated from Patients with ST-Segment Elevation Acute Myocardial Infarction

Introduction Although ruptured atherosclerotic plaques have been extensively analyzed, the composition of thrombi causing arterial occlusion in patients with ST-segment elevation acute myocardial infarction has been less thoroughly investigated. We sought to investigate whether coagulant active tissue factor can be retrieved in thrombi of patients with STEMI undergoing primary percutaneous coronary intervention. Methods Nineteen patients with ST-segment elevation acute myocardial infarction referred for primary percutaneous coronary intervention were enrolled in this study. Coronary thrombi aspirated from coronary arteries were routinely processed for paraffin embedding and histological evaluation (4 patients) or immediately snap frozen for evaluation of tissue factor activity using a modified aPTT test (15 patients). Immunoprecipitation followed by immunoblotting was also performed in 12 patients. Results Thrombi aspirated from coronary arteries showed large and irregular areas of tissue factor staining within platelet aggregates, and in close contact with inflammatory cells. Some platelet aggregates stained positive for tissue factor, whereas others did not. Monocytes consistently stained strongly for tissue factor, neutrophils had a more variable and irregular tissue factor staining, and red blood cells did not demonstrate staining for tissue factor. Median clotting time of plasma samples containing homogenized thrombi incubated with a monoclonal antibody that specifically inhibits tissue factor-mediated coagulation activity (mAb 5G9) were significantly longer than their respective controls (88.9 seconds versus 76.5 seconds, respectively; p<0.001). Tissue factor was also identified by immunoprecipitation in 10 patients, with significant variability among band intensities. Conclusions Active tissue factor is present in coronary artery thrombi of patients with ST-segment elevation acute myocardial infarction, suggesting that it contributes to activate the coagulation cascade ensuing in coronary thrombosis.

Relationship between diabetes, platelet reactivity, and the SYNTAX score to one-year clinical outcome in patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention

AIMS In patients with non-ST-elevation acute coronary syndromes (NSTE-ACS) treated with PCI, high (H) platelet reactivity (PR) significantly affects one-year outcome. The aim of this report was to analyse the relationships between HPR, the SYNTAX score (SS) and one-year major adverse cardiac events (MACE: cardiac death, myocardial infarction, stent thrombosis) according to diabetes mellitus (DM) status in patients included in the GEne Polymorphism, Platelet REactivity, and the Syntax Score (GEPRESS) study. METHODS AND RESULTS PR was measured using the vasodilator-stimulated phosphoprotein (VASP) assay at three time points (before PCI, at hospital discharge and at one month after PCI), with HPR defined as >50% PR index in 1,042 patients treated with aspirin and clopidogrel for one year after PCI. Patients with DM and an SS ≥15 had the highest MACE rate between one month and one year, further increased by the presence of HPR (16.4%). On the other hand, among all patients with an SS <15, MACE rates remained low (<3%), irrespective of DM status and PR. CONCLUSIONS Among NSTE-ACS patients treated with PCI, the combination of DM, an SS ≥15 and HPR characterised a cohort with the highest MACE rate from one month to one year. In such high-risk patients, careful clinical monitoring and implementation of secondary prevention measures, including the use of potent P2Y12 inhibitors, are strongly advised.