RESUMO
BACKGROUND: Whether mutations in the hemochromatosis (HFE) gene increase cardiovascular disease risk is still undetermined. The main reason is the low frequency of the mutations, in particular of the compound C282Y/H63D genotype. We combined the data of 11 observational studies for an individual patient data meta-analysis. METHODS AND RESULTS: Individual patient data were obtained from published as well as unpublished studies that had information available on the C282Y mutation as well as the H63D mutation in relation to coronary heart disease risk. Individual records were provided on each of the 53 880 participants in 11 studies. In total, 10 541 patients with coronary events were documented, of whom 5724 had an acute myocardial infarction. The crude and adjusted association between HFE genotypes and coronary events was examined by logistic regression analysis. We explored potential effect modification of the association between traditional cardiovascular risk factors and coronary events by HFE genotypes. After full adjustment, the odds ratio for coronary heart disease was 1.12 (95% CI, 0.92 to 1.37) for subjects with the compound heterozygous (C282Y/H63D) genotype relative to those with the wild-type/wild-type genotype. The odds ratios for C282Y/C282Y, C282Y/wild-type, H63D/H63D, and H63D/wild-type were 0.78 (95% CI, 0.49 to 1.26), 0.98 (95% CI, 0.90 to 1.07), 1.16 (95% CI, 0.97 to 1.38), and 1.07 (95% CI, 1.00 to 1.14), respectively. There was no evidence for effect modification. CONCLUSIONS: The results of this large individual patient data meta-analysis do not support the view that HFE gene mutations are associated with an increased risk of coronary heart disease or acute myocardial infarction.
Assuntos
Doenças Cardiovasculares/genética , Predisposição Genética para Doença , Antígenos de Histocompatibilidade Classe I/genética , Proteínas de Membrana/genética , Mutação/genética , Feminino , Proteína da Hemocromatose , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fatores de RiscoRESUMO
Two-dimensional (2-D) Blue Native/SDS gel electrophoresis combines a first-dimensional separation of monomeric and multimeric proteins in their native state with a second denaturing dimension. These high-resolution 2-D gels aim at identifying multiprotein complexes with respect to their subunit composition. We applied this method for the first time to analyze two human platelet subproteomes: the cytosolic and the microsomal membrane protein fraction. Solubilization of platelet membrane proteins was achieved with the nondenaturing detergent n-dodecyl-beta-D-maltoside. To validate native solubilization conditions, we demonstrated the correct assembly of the Na,K-ATPase, a functional multimeric transmembrane protein, when expressed in Xenopus oocytes. We identified 63 platelet proteins after in-gel tryptic digestion of 58 selected protein spots and liquid chromatography-coupled tandem mass spectrometry. Nine proteins were detected for the first time in platelets by a proteomic approach. We also show that this technology efficiently resolves several known membrane and cytosolic multiprotein complexes. Blue Native/SDS gel electrophoresis is thus a valuable procedure to analyze specific platelet subproteomes, like the membrane(-bound) protein fraction, by mass spectrometry and immunoblotting and could be relevant for the study of protein-protein interactions generated following platelet activation.
Assuntos
Plaquetas/química , Eletroforese em Gel Bidimensional/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Proteínas de Membrana/sangue , Proteoma/isolamento & purificação , Animais , Humanos , Proteínas de Membrana/isolamento & purificação , Microssomos/metabolismo , Oócitos/metabolismo , Estrutura Quaternária de Proteína , XenopusRESUMO
Carney complex (CNC) is a familial multiple neoplasia syndrome characterized by cardiac and extracardiac myxomas in the setting of spotty skin pigmentation and endocrinopathy. We previously identified PRKAR1A (regulatory subunit 1alpha of protein kinase A) mutations in CNC. Mutational analyses of the PRKAR1A gene in 51 unrelated CNC probands now detect mutations in 65%. All mutations, except for one unique missense mutation, lead to PRKAR1A haploinsufficiency. Therefore, we studied the consequences of prkar1a haploinsufficiency in mice. Although we did not observe cardiac myxomas or altered pigmentation in prkar1a(+/-) mice, we did observe some phenotypes similar to CNC, including altered heart rate variability. Moreover, prkar1a(+/-) mice exhibited a marked propensity for extracardiac tumorigenesis. They developed sarcomas and hepatocellular carcinomas. Sarcomas were frequently associated with myxomatous differentiation. Tumors from prkar1a(+/-) mice did not exhibit prkar1a loss of heterozygosity. Thus, we conclude that although PRKAR1A haploinsufficiency does predispose to tumorigenesis, distinct secondary genetic events are required for tumor formation.
Assuntos
Neoplasia Endócrina Múltipla/genética , Proteínas/genética , Alelos , Animais , Células COS , Chlorocebus aethiops , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico , Proteínas Quinases Dependentes de AMP Cíclico , Análise Mutacional de DNA , Humanos , Camundongos , Camundongos Knockout , Neoplasia Endócrina Múltipla/patologia , Mutação , Mixoma/genética , Mixoma/patologia , Linhagem , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Subunidades Proteicas , Proteínas/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Baço/metabolismo , Baço/patologiaRESUMO
BACKGROUND: The use of intravenous glycoprotein IIb/IIIa-receptor antagonists has been shown to improve outcomes in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). Tirofiban has shown benefit in a wide range of patients presenting with acute coronary syndromes. Although this agent has been used in patients undergoing percutaneous coronary intervention, a literature search identified no prospective data comparing tirofiban with placebo in patients undergoing planned intracoronary stent placement. OBJECTIVE: This study examined the tolerability of tirofiban in patients undergoing percutaneous intervention with planned intracoronary stent placement. METHODS: This was a multinational, multicenter, prospective, randomized, double-blind, placebo-controlled trial in patients scheduled to undergo PTCA with planned intracoronary stent placement. Patients were randomized in a 3:2 ratio to receive tirofiban as an intravenous bolus (10 microg/kg over 3 minutes) and maintenance infusion (0.10 microg/kg per minute for 36 hours) or a bolus and infusion of placebo. All patients received periprocedural aspirin and heparin and an optional postprocedural thienopyridine (ticlopidine or clopidogrel). Laboratory and safety monitoring were performed throughout the 36 hours after the procedure and at hour 40 or hospital discharge. The primary end point was the proportion of patients with bleeding, defined according to Thrombolysis in Myocardial Infarction (TIMI) trial criteria. The number of patients with cardiac events (death, myo- cardial infarction, urgent revascularization) during the first 30 days after stent placement was also assessed. RESULTS: Eight hundred ninety-four patients (536 tirofiban, 358 placebo) were enrolled, all of whom received aspirin and heparin periprocedurally and optional ticlopidine or clopidogrel after the procedure. No significant between-group differences were observed in the incidence of TIMI major bleeding (0.2% tirofiban, 0.6% placebo) or any TIMI bleeding (3.2% and 1.7%, respectively). The incidence of TIMI minor bleeding was higher with tirofiban than with placebo (2.8% vs 0.6%). The 30-day incidence of the composite end point of any cardiac event was 3.9% in both groups. CONCLUSIONS: On a background of concomitant aspirin, heparin, and a thienopyridine, tirofiban was generally well tolerated in patients undergoing PTCA with planned intracoronary stent placement. Further investigation is needed to ascertain the optimal dosing of tirofiban and heparin to achieve reductions in ischemic complications of intracoronary stenting with an acceptable incidence of bleeding complications.
Assuntos
Angioplastia Coronária com Balão , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Tirosina/uso terapêutico , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Stents , Tirofibana , Tirosina/análogos & derivadosRESUMO
BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) have an increased risk of cardiovascular events including myocardial infarction and stroke. OBJECTIVE: To determine whether in vivo platelet activation and the generation of procoagulant platelet-derived microparticles (PMP) are increased during sleep in patients with OSAS. METHODS: In vivo platelet activation and PMP formation was determined using flow cytometry in 12 patients with untreated OSAS during and after sleep (4 and 7 a.m.). To study the effect of treatment with continuous positive airway pressure (CPAP), the measurements were repeated at the same time points after initiation of CPAP therapy. Healthy volunteers served as controls (n = 6). RESULTS: Patients with OSAS had an increased percentage of platelets positive for the activation-dependent epitopes CD63 and CD62P during sleep (4 a.m.) compared to controls (4.8 +/- 0.8 vs. 1.9 +/- 0.4% for CD63, p < 0.01, and 2.0 +/- 0.5 vs. 1.1 +/- 0.3% for CD62P, p < 0.05). In OSAS patients, the amount of CD63- and CD62P-positive platelets was significantly elevated at 4 compared to 7 a.m. (4.8 +/- 0.8 vs. 2.6 +/- 0.4% for CD63 and 2.0 +/- 0.5 vs. 1.1 +/- 0.2% for CD62P, p < 0.05), but not in the control group. The levels of PMP were similar in patients with OSAS and controls at 4 and 7 a.m. After 1 night of CPAP therapy, there was a trend to reduced levels of CD63- and CD62P-positive platelets at 4 a.m. CONCLUSIONS: Patients with OSAS have increased in vivo platelet activation during sleep, which may contribute to the increased incidence of cardiovascular events in patients with OSAS.
Assuntos
Ativação Plaquetária , Apneia Obstrutiva do Sono/fisiopatologia , Sono/fisiologia , Idoso , Antígenos CD/análise , Epitopos , Humanos , Masculino , Pessoa de Meia-Idade , Selectina-P/análise , Glicoproteínas da Membrana de Plaquetas/análise , Tetraspanina 30RESUMO
The major goal of myocardial reperfusion therapy is to restore normal coronary blood flow as quickly as possible and to maintain coronary patency in the highest number of patients with acute myocardial infarction. Recent studies support the hypothesis that more rapid and complete restoration of coronary flow through the infarct-related artery results in improved ventricular performance and lower mortality. Accelerated tissue plasminogen activator therapy appears to produce the most favorable effects compared to other lytic strategies, particularly in patients with anterior and large myocardial infarctions. However, the finding in GUSTO II trial, that even with the best strategy only 54% of patients had TIMI grade 3 flow, suggests that further improvement in the treatment of acute myocardial infarction may be possible in the future. The effectiveness of thrombolytic therapy may be enhanced by earlier identification of evolving myocardial infarction and reduced time delays in the initiation of thrombolytic therapy, bolus thrombolytic therapy, new thrombolytic agents, or more potent adjunctive antithrombotic strategies.