1,721,003 research outputs found
Mechanism for antiplatelet action of statins
No full textHydroxymethyl-glutaryl coenzyme A reductase inhibitors (statins) offer important benefits for the large populations of individuals at high risk for coronary heart and cerebrovascular disease. the overall clinical benefits observed with statin therapy appear to be greater than what might be expected from changes in lipid profile alone, suggesting that the beneficial effects of such drugs may extend beyond their effects on serum cholesterol. Platelet hyperactivity is a key step in atherothrombosis and experimental data suggest that statins could exert an antiplatelet effect which could be involved in their protective action. In the present review we report of the major studies in humans showing the effect of statins on platelets, especially by the more sensitive methods to explore platelet function such as cytofluorymetric detection of specific proteins. Moreover we describe the putative mechanisms involved in platelet deactivation with particular regard to the effects related to cholesterol reduction or beyond lipid-lowering. Indeed, data from several studies suggest some differences among compounds in terms of timing of action by modulation of several activating pathways which could take part either in the early, cholesterol-lowering independent, effects in the acute phase of vascular disease or during chronic treatment. © 2005 Bentham Science Publishers Ltd
Cytokines in acute coronary syndromes
No full textThe aim of this study was to show the presence of an imbalance between pro-inflammatory and anti-inflammatory mediators in patients affected by acute coronary syndromes (ACS). We evaluated the production in cultured and stimulated lymphomonocytes of interferon (IFN)γ and tumor necrosis factor (TNF)α, which are well known to possess pro-inflammatory effects, and of interleukin (IL)10, which has been shown to have a protective anti-inflammatory activity, in two groups of 30 patients affected by acute myocardial infarction (AMI) and unstable angina (UA), compared with two equivalent groups of patients with stable angina (SA) and of healthy volunteers. We found a significant increase of IFNγ and TNFα production (p < 0.01) and a significant decrease of IL-10 production (p < 0.01) in cultures of lymphomonocytes taken from patients with AMI and UA compared with SA patients and controls. No significant changes were found between AMI and UA patients and SA patients and controls. We conclude that a relevant imbalance in cytokine release is present in ACS, markedly favoring pro-inflammatory effects. © 2005 Elsevier Ireland Ltd. All rights reserved
T cell activation and enhanced apoptosis in non-ST elevation myocardi infarction
No full textRecent studies have shown that inflammation plays a major role in coronary plaque destabilization and in the induction of thrombosis in acute coronary syndromes. The aim of this study was to evaluate circulating lymphocyte activation and apoptosis in patients with non-ST elevation myocardial infarction (NSTEMI) in comparison with subjects with stable angina and with age-matched healthy controls. We considered T cell subpopulations, T cell surface HLA-DR and CD69 expression (evaluated by flow cytometry), lymphomonocyte spontaneous apoptosis (evaluated by ELISA), and IL2 production (evaluated by ELISA) in peripheral blood within 6 hours of onset of NSTEMI. We also investigated Fas expression on T cells (evaluated by flow cytometry) and FasL mRNA (evaluated by RT-PCR), as well as Fas functionality. In NSTE-MI patients we found a significant increase of HLA-DR+CD3+ and CD69+CD4+ cells. Spontaneous apoptosis was significantly increased in NSTEMI patients in comparison with the two control groups and was associated with an increased expression of Fas, an increased susceptibility to Fas agonist (CH11), and a normal production of IL2 in cell cultures. These data suggest that the enhanced apoptosis is due to a mechanism of "active" antigen-driven death, induced by the expression of death cytokines and not by the failure of cell growth factors. We conclude that peripheral lymphocytes are activated in NSTEMI and undergo an enhanced programmed cell death due to activation mechanisms. It is likely that lymphocyte activation occurs before the onset of acute ischemia and contributes to the plaque rupture and to the myocardial ischemic insult
Diatolic filling in hypertrophied hearts of elite runners: an echo-doppler study
No full textThe aim of this study was to establish if the physiologic adaptations following a prolonged physical training could influence the diastolic function in a professional Olympic male runner group. From February to December 1999 we studied 25 athletes (Group I) during the period of maximal training compared with 18 healthy sedentary subjects of matched age and sex (Group II). We used mono and bidimensional Echocardiography to assess left ventricular structure and systolic function. The diastolic function was evaluated by Doppler method assessing transmitral and venous pulmonary flow. From the comparison between the two groups, we found great differences in the interventricular septum and the posterior wall thickness; the analysis of the systolic function demonstrated a significant increase in ejection fraction, stroke volume, left ventricular mass, and end-diastolic volume in the athletes' population. Fluximetric study of transmitral and pulmonary venous flow showed that ventricular diastolic function is not influenced by hypertrophy. Our data indicate that diastolic function remains normal or improves in some cases after physical training; left ventricular hypertrophy and concentric remodeling do not involve diastolic changes like hypertrophic and hypertensive heart diseases
Statins discontinuation in compliant chronic users induces atherothrombotic profile despite baseline clinical setting and treatments
No full textLevosimendan improves pro/anti-inflammatory cytokines imbalance in male patients with advanced heart failure. A randomized, double-blind, placebo-controlled study
No full textComplement activation in hypercholesterolemia
No full textBackground and Aim: Inflammatory and lipid factors share an important role in atherosclerosis. This study evaluates their relations in dyslipidemic subjects. Methods and Results: We compared the complement system (serum hemolytic activity CH50, C3 and C4 fractions and terminal complex sC5b-9) in 30 hypercholesterolemic patients with elevated cholesterol and decreased HDL-cholesterol levels, 30 normolipemic patients with clinical atherosclerosis and 30 matched normal subjects. In addition we evaluated the circulating immune complexes containing cholesterol (chol-CIC) on the assumption that they might be important in complement activation, and the circulating levels of the adhesion molecule 1CAM-1 (sICAM-1) as a sign of endhotelial dysfunction. We found a significant increase of sC5b-9 (but not of CH50 and C3, C4) in the hypercholesterolemics compared with the other groups. The plasma sC5b-9 level was inversely and significantly related to HDL-chol (regression analysis), whereas no direct significant relation was found between sC5b-9 and cholesterol. Chol-CIC were also significantly increased in this group. The atherosclerosis patients also presented a significant increase of sC5b-9. Lastly, both patient groups displayed a significant increase of sICAM-1. Conclusions: We suggest that complement activation in dyslipidemics may be induced by their increased immune complexes. However, the decrease of complement regulatory proteins carried by HDL is another important factor, while complement changes may be related to variations of other humoral and cell systems (endothelium, coagulative/fibrinolytic system), whose involvement is suggested in our study by the changes of sICAM-1. ©, Medikal Press
Atorvastatin reduces platelet-oxidized-LDL receptor expression in hypercholesterolaemic patients
No full textBACKGROUND: Oxidized-LDL (ox-LDL) are proatherogenic and platelet-activating molecules. Atorvastatin reduces platelet activity before cholesterol-lowering action. CD36 and lectin-like oxidized-LDL receptor-1 (LOX-1) are specific ox-LDL receptors expressed also in platelets. This study was planned to address whether the possible rapid effect of atorvastatin on platelets could be related to modulation of ox-LDL receptors.
MATERIALS AND METHODS: Forty-eight hypercholesterolaemic subjects requiring statin treatment (atorvastatin 20 mg day(-1)) after an ineffective diet regimen were evaluated for complete lipid-profile (chromogenic); P-selectin (P-sel), CD36 and LOX-1 expression (cytofluorimetric detection); circulating and platelet-associated ox-LDL (ox- and Pox-LDL, ELISA); and intracellular citrullin recovery (iCit, HPLC) at baseline and 3, 6 and 9 days after inclusion in the study. Moreover, we studied 48 normal controls matched for sex and age.
RESULTS: Platelet activity expressed by P-sel (in resting and thrombin-activated cells), CD36 and LOX-1 were increased in hypercholesterolaemic subjects (all P < 0.01). Atorvastatin induced a reduction of CD36 at 6 days (P < 0.05); and P-sel in resting (P < 0.001) and activated cells (P < 0.001) and LOX-1 were reduced at 9 days (all P < 0.001) in association with decreased Pox-LDL (P < 0.001) and increased iCit (P < 0.01). All data were obtained before a significant reduction of LDL and ox-LDL was achieved (P = 0.109 and 0.113).
DISCUSSION: Present data suggest that platelet deactivation by atorvastatin is related to CD36 and LOX-1 expression reduction before significant LDL changes. Moreover, the modulation of LOX-1 can be considered a self-relevant antiatherothrombotic action of atoravastin owing to the important role of this receptor in the ox-LDL-mediated vascular damag
Enhanced apoptosis of peripheral blood mononuclear cells (PBMC) in cardiac transplanted patients undergoing chronic immunosuppressive treatment
No full textApoptosis plays a major role in tissue transplantation because intact T-cell-apoptosis pathways are required for the induction of tolerance to allografts. Moreover, immunosuppressive agents commonly used in clinical transplantation medicine promote lymphocyte apoptosis inhibiting the expression and production of cytokines involved in lymphocyte survival. The aim of our study was to evaluate peripheral blood mononuclear cells (PBMC) spontaneous apoptosis in patients undergoing chronic immunosuppressive treatment after cardiac transplantation. PBMC obtained from patients (n = 31) and controls matched for age and sex (n = 25) were cultured for 72 h and apoptosis was evaluated by quantification of fragmented DNA, staining with Hoechst 33258 dye and annexin V binding. We also investigated Fas expression and FasL mRNA expression as well as the ability of an IgM anti-Fas antibody to induce apoptosis. Finally, we evaluated IL2 production induced by PHA and the ability of IL2 to prevent apoptosis. In patients, PBMC underwent enhanced spontaneous apoptosis in comparison with controls. However, we could not find any difference between patients and normals as regards the expression of Fas and of FasL mRNA, even if the cross-linking of the Fas molecule induced apoptosis in PBMC from patients, whereas it failed to induce cell death in normals. We also found that IL2 production was significantly decreased in patients and that the addition of IL2 to the culture medium reduced PBMC spontaneous apoptosis. Our findings suggest that in cardiac transplanted patients PBMC undergo enhanced spontaneous apoptosis, which may contribute to prevent allograft rejection
Effects ofthymopoietin pentapeptide on low reversible E-rosette forming cells of rheumatoidarthritis patients.-II) In vivo study
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