RESUMO
Antiplatelet medications remain a cornerstone of therapy for atherosclerotic cardiovascular and cerebrovascular diseases. In primary prevention (patients with cardiovascular risk factors but no documented events, symptoms or angiographic disease), there is little evidence of benefit of any antiplatelet therapy, and such therapy carries the risk of excess bleeding. Where there is documented disease (secondary prevention), stable patients benefit from long-term antiplatelet monotherapy, aspirin being first choice in those with coronary heart disease and clopidogrel in those with cerebrovascular disease; moreover, recent evidence shows that low-dose rivaroxaban in combination with aspirin confers added benefit, in patients with stable cardiovascular and peripheral arterial disease. In patients with acute cerebrovascular disease, aspirin combined with clopidogrel reduces subsequent risk, while in acute coronary syndrome, dual antiplatelet therapy comprising aspirin and a P2Y12 inhibitor (clopidogrel, prasugrel or ticagrelor) confers greater protection than aspirin monotherapy, with prasugrel and ticagrelor offering greater antiplatelet efficacy with faster onset of action than clopidogrel. Although greater antiplatelet efficacy is advantageous in preventing thrombotic events, this must be tempered by increased risk of bleeding, which may be a particular issue in certain patient groups, as will be discussed. We will also discuss possible future approaches to personalisation of antiplatelet therapy.
Assuntos
Síndrome Coronariana Aguda , Doenças Cardiovasculares , Síndrome Coronariana Aguda/tratamento farmacológico , Aspirina , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/prevenção & controle , Clopidogrel , Hemorragia/induzido quimicamente , Hemorragia/tratamento farmacológico , Humanos , Inibidores da Agregação Plaquetária/efeitos adversos , Cloridrato de Prasugrel/efeitos adversos , Ticagrelor/uso terapêuticoRESUMO
Cardiovascular disease (CVD) represents the leading cause of death worldwide, and equally affects both sexes although women develop disease at an older age than men. A number of clinical evidence has identified the female sex as an independent factor for poor prognosis, with the rate of mortality and disability following an acute cardiovascular (CV) event being higher in women than men. It has been argued that the different level of platelet reactivity between sexes may account for a different responsiveness to anti-platelet therapy, with consequent important implications on clinical outcomes. However, conclusive evidence supporting the concept of a gender-dependent effectiveness of platelet inhibitors are lacking. On the contrary, sex-related dissimilarities have been evidenced in cardiovascular patients in terms of age of presentation, comorbidities such as obesity, diabetes and renal disease, and a different pharmacological approach to and effectiveness in controlling classical cardiovascular risk factors such as hypertension, glucose profile and lipid dysmetabolism. All these factors could place women at an increased level of cardiovascular risk compared to men, and may concur to an enhanced pro-thrombogenic profile. The purpose of this manuscript is to provide an overview of gender-related differences in cardiovascular treatment, in order to highlight the need to improve the pharmacological prophylaxis adopted in women through a more accurate evaluation of the overall cardiovascular risk profile with consequent establishment of a more effective and targeted anti-thrombotic strategy which is not limited to the use of anti-platelet agents.
Assuntos
Plaquetas/efeitos dos fármacos , Doenças Cardiovasculares/prevenção & controle , Inibidores da Agregação Plaquetária/uso terapêutico , Plaquetas/patologia , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/patologia , Feminino , Humanos , Masculino , Inibidores da Agregação Plaquetária/farmacologia , Prognóstico , Caracteres Sexuais , Fatores SexuaisRESUMO
Thrombogenic and inflammatory activity are two distinct aspects of platelet biology, which are sustained by the ability of activated platelets to interact with each other (homotypic aggregation) and to adhere to circulating leucocytes (heterotypic aggregation). These two events are regulated by distinct biomolecular mechanisms that are selectively activated in different pathophysiological settings. They can occur simultaneously, for example, as part of a pro-thrombotic/pro-inflammatory response induced by vascular damage, or independently, as in certain clinical conditions in which abnormal heterotypic aggregation has been observed in the absence of intravascular thrombosis. Current antiplatelet drugs have been developed to target specific molecular signalling pathways mainly implicated in thrombus formation, and their ever increasing clinical use has resulted in clear benefits in the treatment and prevention of arterial thrombotic events. However, the efficacy of currently available antiplatelet drugs remains suboptimal, most likely because their therapeutic action is limited to only few of the signalling pathways involved in platelet homotypic aggregation. In this context, modulation of heterotypic aggregation, which is believed to contribute importantly to acute thrombotic events, as well to the pathophysiology of atherosclerosis itself, may offer benefits over and above the classical antiplatelet approach. This review will focus on the distinct biomolecular pathways that, following platelet activation, underlie homotypic and heterotypic aggregation, aiming potentially to identify novel therapeutic targets.
Assuntos
Plaquetas/efeitos dos fármacos , Ativação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/uso terapêutico , Agregação Plaquetária/efeitos dos fármacos , Aspirina/farmacologia , Aspirina/uso terapêutico , Humanos , Leucócitos/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Tienopiridinas/farmacologia , Tienopiridinas/uso terapêutico , Trombose/prevenção & controleRESUMO
BACKGROUND: Migratory ability of resident endothelial cells and their circulating progenitors, that is endothelial progenitor cells (EPCs), represent a crucial event in vascular repairing processes. Although oxidants are known to counteract the migratory ability of resident endothelial cells, their possible role in modulating EPC motility is unknown. EPCs exhibit stronger resistance to oxidants than mature endothelial cells mainly because of higher expression of manganese (Mn) superoxide dismutase (SOD). As nifedipine is a dihydropyridine calcium antagonist known to enhance MnSOD expression in mature endothelial cells, we investigated the effects of nifedipine on MnSOD expression and motility in EPCs. METHODS AND RESULTS: EPCs were isolated from peripheral blood of healthy donors and cultured in fibronectin-coated flasks. Nifedipine improved both motility of cultured EPCs (+55% vs. control, P = 0.007) and their adhesion to tumor necrosis factor-alpha-activated mature endothelial cells (+33% vs. control, P = 0.03). Reduction of EPC dichlorofluorescein content (-32% vs. control, P = 0.009) and a parallel increase in nitrite plus nitrate concentration in EPC supernatants (+25% vs. control, P = 0.009) were also observed. The study of SOD showed a nifedipine-dependent upregulation of MnSOD in a time-dependent and dose-dependent manner. MnSOD expression blockade by RNA interference abolished nifedipine effect on EPC motility. Although nifedipine also increased vascular endothelial growth factor (VEGF) release from EPCs, its effect on EPC motility was unaffected by an anti-VEGF antibody. CONCLUSION: Nifedipine improves EPC motility due to MnSOD upregulation. The capability of this dihydropyridine calcium antagonist to reduce cardiovascular events might also be related to improved EPC function.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Movimento Celular/efeitos dos fármacos , Células Endoteliais/citologia , Nifedipino/farmacologia , Células-Tronco , Superóxido Dismutase/genética , Adulto , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Nitratos/metabolismo , Nitritos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/enzimologia , Superóxido Dismutase/metabolismo , Regulação para Cima/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
BACKGROUND: Hypertensives with a blunted nocturnal blood pressure (BP) decrease have increased risk of developing atherosclerotic disease. Soluble CD40 ligand (sCD40L) is involved in the pathogenesis of risk factor-related vascular damage. Therefore, we evaluated the relationship between circulating sCD40L levels, circadian BP profile, and early carotid atherosclerosis in essential hypertensives. METHODS: Plasma sCD40L concentrations were assessed in two groups of 25 never-treated hypertensives, without additional cardiovascular risk factors, differentiated on the basis of a nocturnal decrease of BP either of >10% (dippers) or <10% (nondippers) of daytime values, and in 25 matched normotensives. Carotid intima-media thickness (IMT) was also measured in all participants. RESULTS: Plasma sCD40L concentrations were higher in nondippers (4.9 +/- 1.2 ng/mL) than in dippers (3.7 +/- 0.7, P = .0005) and controls (1.6 +/- 0.6, P < .0001). These latter had lower sCD40L concentrations than dippers (P < .0001). The IMT was higher in both hypertensive groups than in normotensives (P < .0001). In the entire hypertensive population IMT directly correlated with circulating levels of sCD40L (r = 0.365, P = .01) and inversely correlated with nocturnal systolic BP decreases (r = -0.286, P = .043). In a multivariate regression analysis sCD40L was the main determinant of IMT (r(2) = 0.157, P = .004). CONCLUSIONS: Nondippers have enhanced plasma sCD40L levels, which may contribute to their increased susceptibility to develop vascular damage.
Assuntos
Pressão Sanguínea/fisiologia , Ligante de CD40/sangue , Ritmo Circadiano/fisiologia , Hipertensão/fisiopatologia , Proteína C-Reativa/metabolismo , Artéria Carótida Primitiva/patologia , Humanos , Hipertensão/sangue , Hipertensão/patologia , Isoprostanos/sangue , Pessoa de Meia-Idade , Ativação Plaquetária/fisiologiaRESUMO
In atherosclerotic animal models, the cyclo-oxygenase (COX)-inhibitor aspirin counteracts downregulation of endothelial-derived netrin-1, thus reducing arterial inflammation. We here explored the effect of aspirin on netrin-1 in healthy subjects undergoing influenza immunisation, which is an established experimental model of inflammation-related endothelial dysfunction. Our data showed that netrin-1 undergoes reduction (-29.25% from baseline; p=0.0017) in the presence of endothelial activation (VCAM-1 rose by 9.98% 2-days post-vaccination; p=0.0022). Aspirin counteracted vaccine-induced endothelial activation and reduction of netrin-1 in a dose-dependent manner (-3.06% and -17.03% from baseline at a dose of 300mg and 75mg respectively; p=0.0465 and p>0.05 vs untreated). Clopidogrel, which was used as a comparator due to its similar anti-platelet activity, also reduced endothelial activation but, unlike aspirin, enhanced netrin-1 levels (+20.96% from baseline; p=0.0033 vs untreated). A correlation analysis incorporating cytokines, hs-CRP, VCAM-1, TXB2 and PGE2, showed that changes in netrin-1 were directly related to PGE2 variations only (r=0.6103; p=0.0002). In a separate population of 40 healthy unimmunised volunteers, 28-day treatment with aspirin 300mg reduced netrin-1 (-18.76% from baseline; p=0.0012) without affecting endothelial markers or hs-CRP; as expected, aspirin suppressed TXB2 and PGE2. Netrin-1 and PGE2 levels were directly related (r=0.358; p=0.0015), but other parameters including TXB2, hs-CRP and endothelial markers, were not. In conclusion, aspirin counteracts downregulation of netrin-1 following endothelial dysfunction due to its anti-inflammatory effect on the activated endothelium. However, inhibition of COX-dependent prostanoids negatively modulates netrin-1 synthesis in healthy subjects, and this could give rise to aspirin-dependent reduction in netrin-1 under steady state conditions.
RESUMO
Anti-inflammatory add-on therapy to conventional cardiovascular prophylaxis has been proposed as a novel therapeutic approach to potentially reduce residual cardiovascular risk. This hypothesis has been challenged by a series of unsuccessful Phase III studies testing the impact on clinical outcomes of novel agents with immunomodulatory actions. Specifically, the apparent ability of phospholipase A2 (PLA2) inhibitors and of antioxidants to ameliorate inflammation and to reduce coronary disease in Phase II trials did not translate into improved secondary cardiovascular prevention in larger population-based studies. Other anti-inflammatory agents are still under scrutiny. However, studies to date have lacked information on the inflammatory profile of the participants, both at baseline and at follow-up, thereby limiting the possibility of identifying subgroups of patients in whom 'residual inflammation' can be detected despite optimal conventional therapy, and who could therefore benefit from a cardiovascular prevention strategy specifically targeting inflammation. This has also rendered it difficult to interpret the results as a conclusive demonstration of inefficacy of the tested anti-inflammatory strategies in the treatment of atherosclerosis. We here discuss the importance of better patient characterization to minimize heterogeneity of the study population, so that effectiveness of different anti-inflammatory strategies can be evaluated in targeted subgroups of patients. We also illustrate how specific inflammatory biomarkers could assist in this process, with particular emphasis on the roles of high-sensitivity C-reactive protein and circulating monocyte phenotype.
Assuntos
Anti-Inflamatórios/uso terapêutico , Proteína C-Reativa/análise , Doenças Cardiovasculares/tratamento farmacológico , Monócitos/fisiologia , Aterosclerose/etiologia , Biomarcadores , Doenças Cardiovasculares/etiologia , Quimiocina CCL5/fisiologia , Humanos , Lipoproteínas LDL , Inibidores de Fosfolipase A2/farmacologia , Prognóstico , Receptores de IgG/análise , Fator de Necrose Tumoral alfa/antagonistas & inibidoresRESUMO
AIMS: Levels of circulating CD14(high)CD16(+) monocytes increase in atherosclerotic patients and are predictive of future cardiovascular events. Platelet activation has been identified as a crucial determinant in the acquisition of a CD16(+) phenotype by classical CD14(high)CD16(-) cells. We tested the hypothesis that anti-platelet drugs modulate the phenotype of circulating monocytes. METHODS AND RESULTS: Sixty healthy subjects undergoing influenza immunization were randomly assigned to either no treatment or anti-platelet therapy, namely aspirin 300 mg or 75 mg daily, or clopidogrel (300 mg loading dose followed by 75 mg), for 48 h post-immunization (n = 15/group). Monocyte subsets, high-sensitivity C-reactive protein, pro-inflammatory cytokines, and P-selectin were measured at baseline and post-immunization. The CD14(high)CD16(+) monocyte cell count rose by 67.3% [interquartile range (IQR): 35.7/169.2; P = 0.0002 vs. baseline] in untreated participants. All anti-platelet regimes counteracted expansion of this monocytic subpopulation. Although no statistical differences were noted among the three treatments, aspirin 300 mg was the most efficacious compared with the untreated group (-12.5% change from baseline; IQR: -28.7/18.31; P = 0.001 vs. untreated). Similarly, the rise in P-selectin (17%; IQR: -5.0/39.7; P = 0.03 vs. baseline) observed in untreated participants was abolished by all treatments, with aspirin 300 mg exerting the strongest effect (-30.7%; IQR: -58.4/-0.03; P = 0.007 vs. untreated). Changes in P-selectin levels directly correlated with changes in CD14(high)CD16(+) cell count (r = 0.5; P = 0.0002). There was a similar increase among groups in high-sensitivity C-reactive protein (P < 0.03 vs. baseline levels). CONCLUSIONS: Anti-platelet drugs exert an immunomodulatory action by counteracting CD14(high)CD16(+) monocyte increase under pro-inflammatory conditions, with this effect being dependent on the amplitude of P-selectin reduction.
Assuntos
Aspirina/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Fatores Imunológicos/administração & dosagem , Inflamação/sangue , Vacinas contra Influenza/administração & dosagem , Receptores de Lipopolissacarídeos/sangue , Monócitos/efeitos dos fármacos , Inibidores da Agregação Plaquetária/administração & dosagem , Receptores de IgG/sangue , Ticlopidina/análogos & derivados , Adulto , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , Clopidogrel , Citocinas/sangue , Feminino , Citometria de Fluxo , Proteínas Ligadas por GPI/sangue , Humanos , Inflamação/imunologia , Mediadores da Inflamação/sangue , Londres , Masculino , Monócitos/imunologia , Monócitos/metabolismo , Selectina-P/sangue , Fenótipo , Ticlopidina/administração & dosagem , VacinaçãoRESUMO
Obesity in adulthood is combined with vascular endothelial cell and platelet activation. In this study we evaluated whether or not such activation is already present in obese children. Forty obese (10.3 +/- 2.5 yr) and 40 nonobese (10.3 +/- 2.3 yr) children were studied. Circulating levels of soluble (s) intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, as indices of vascular endothelial cell activation, were assessed in both groups. Plasma concentrations of sP-selectin and sCD40 ligand, as indices of platelet activation, were also measured. Circulating levels of highly sensitive C-reactive protein (hs-CRP) and the lipid peroxidation product 8-iso-prostaglandin (PG)F(2alpha) were evaluated because of their ability to promote vascular endothelial cell and platelet activation. Circulating levels of all of the assessed markers were higher in obese than in nonobese children (sICAM-1, +38.8 +/- 13.3%; sVCAM-1, +26.5 +/- 13.7%; sE-selectin, +31.3 +/- 17.3%; sP-selectin, +31.7 +/- 16.9%; sCD40 ligand, +36.9 +/- 22.1%; total 8-iso-PGF(2alpha), +24.0 +/- 20.2%; hs-CRP, +76.6 +/- 12.9%; P < 0.0001). Significant correlations (P < 0.004) between plasma total 8-iso-PGF(2alpha) levels and circulating sICAM-1 (r = 0.485), sVCAM-1 (r = 0.506), sP-selectin (r = 0.449), sCD40 ligand (r = 0.498), and hs-CRP (r = 0.520) concentrations were found in obese children. In conclusion, an early activation of vascular endothelial cells and platelets was present in obese children. Increased lipid peroxidation was also present in these children and likely contributed to the observed proinflammatory phenotype.
Assuntos
Endotélio Vascular/fisiopatologia , Molécula 1 de Adesão Intercelular/sangue , Obesidade/fisiopatologia , Ativação Plaquetária/fisiologia , Molécula 1 de Adesão de Célula Vascular/sangue , Área Sob a Curva , Biomarcadores/sangue , Glicemia/metabolismo , Pressão Sanguínea , Criança , Selectina E/sangue , Humanos , Insulina/sangue , Lipídeos/sangue , Masculino , Obesidade/sangue , Valores de ReferênciaRESUMO
Netrins are a family of laminin-like proteins, which were initially identified for their role in embryonic axonal guidance. Over recent years, it has become apparent that netrin-1 may additionally be involved in the underlying pathology of several multisystem diseases, making it an attractive potential therapeutic target. It is involved in postnatal angiogenesis, particularly in the context of an ischaemic insult, although there are conflicting reports as to whether netrin-1 acts in a pro- or anti-angiogenic capacity. In atherosclerosis, opposing effects have similarly been reported on plaque progression, due to the ability of netrin-1 to inhibit both macrophage egress from and monocyte ingress into lesions. Netrin-1 has also been shown to exert a cardioprotective action in the context of ischaemia-reperfusion injury following myocardial infarction. Moreover, urinary netrin-1 levels rise in response to acute kidney injury and at a faster rate than traditional markers of renal impairment, highlighting a potential clinical role for netrin-1 as a biomarker of renal function. The increased urinary excretion of netrin-1 during kidney disease is paralleled by a down-regulation of its plasma levels, with potential implications at a systemic level. In summary, the role of netrin-1 in cardiovascular disease is an emerging area of research requiring further in-depth study to elucidate its mechanism of action and potential as a therapeutic target, especially in view of its seemingly contradictory actions in certain physiological pathways which serve to highlight its manifold and often opposite effects in numerous physiological and pathophysiological processes.
Assuntos
Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/terapia , Nefropatias/metabolismo , Neovascularização Patológica/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Biomarcadores/metabolismo , Doenças Cardiovasculares/complicações , Regulação para Baixo/fisiologia , Humanos , Nefropatias/complicações , Netrina-1RESUMO
BACKGROUND AND PURPOSE: There are conflicting data regarding whether netrin-1 retards or accelerates atherosclerosis progression, as it can lead either to monocyte repulsion from or retention within plaques depending on its cellular source. We investigated the effect of aspirin, which is widely used in cardiovascular prophylaxis, on the synthesis of different isoforms of netrin-1 by endothelial cells under pro-inflammatory conditions, and defined the net effect of aspirin-dependent systemic modulation of netrin-1 on atherosclerosis progression. EXPERIMENTAL APPROACH: Netrin-1 synthesis was studied in vitro using human endothelial cells stimulated with TNF-α, with or without aspirin treatment. In vivo experiments were conducted in ApoE(-/-) mice fed with a high-fat diet (HFD), receiving either aspirin or clopidogrel. KEY RESULTS: TNF-α-induced NF-κB activation up-regulated the nuclear isoform of netrin-1, while simultaneously reducing secreted netrin-1. Down-regulation of the secreted isoform compromised the chemorepellent action of the endothelium against monocyte chemotaxis. Aspirin counteracted TNF-α-mediated effects on netrin-1 synthesis by endothelial cells through COX-dependent inhibition of NF-κB and concomitant histone hyperacetylation. Administration of aspirin to ApoE(-/-) mice on HFD increased blood and arterial wall levels of netrin-1 independently of its effects on platelets, accompanied by reduced plaque size and content of monocytes/macrophages, compared with untreated or clopidogrel-treated mice. In vivo blockade of netrin-1 enhanced monocyte plaque infiltration in aspirin-treated ApoE(-/-) mice. CONCLUSIONS AND IMPLICATIONS: Aspirin counteracts down-regulation of secreted netrin-1 induced by pro-inflammatory stimuli in endothelial cells. The aspirin-dependent increase of netrin-1 in ApoE(-/-) mice exerts anti-atherogenic effects by preventing arterial accumulation of monocytes.
Assuntos
Aspirina/farmacologia , Histonas/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Monócitos/citologia , Monócitos/efeitos dos fármacos , Fatores de Crescimento Neural/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Acetilação/efeitos dos fármacos , Animais , Apolipoproteínas E/deficiência , Apolipoproteínas E/metabolismo , Aspirina/administração & dosagem , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , Camundongos , Camundongos Knockout , Monócitos/metabolismo , Fatores de Crescimento Neural/biossíntese , Netrina-1 , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Supressoras de Tumor/biossínteseRESUMO
Hypercholesterolemia is combined with enhanced lipid peroxidation, which can promote atherogenesis by inducing endothelial adhesion molecule expression. Statins may protect vascular endothelium in hypercholesterolemia by reducing enhanced plasma levels of low-density lipoprotein and decreasing oxidative stress. Herein, we describe increased circulating levels of soluble intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin and total 8-iso-prostaglandin F(2 alpha) (8-iso-PGF(2 alpha)) concentrations, as indexes of endothelial activation and lipid peroxidation, respectively, in 67 hypercholesterolemic patients compared with 32 normocholesterolemic subjects. Significant cholesterol reductions were achieved in hypercholesterolemic patients after 6 months under either simvastatin (40 mg/d) or bezafibrate (800 mg/d) treatment, given according to a randomized double-blind trial. Simvastatin but not bezafibrate simultaneously reduced soluble adhesin and total 8-iso-PGF(2 alpha) concentrations also. Vitamin E supplementation (400 IU/d) further reduced indexes of endothelial activation and lipid peroxidation in simvastatin-treated patients and significantly reduced the above indexes in bezafibrate-treated patients. Changes in circulating soluble adhesion molecule levels were directly correlated with changes in total 8-iso-PGF(2 alpha) concentrations in simvastatin-treated patients also receiving vitamin E supplementation. All together, our data demonstrated that hypercholesterolemia was combined with endothelial activation and lipid peroxidation, which were efficaciously counteracted by simvastatin but not bezafibrate treatment. Thus, a different vascular protection can be achieved by different lipid-lowering treatments.
Assuntos
Anticolesterolemiantes/administração & dosagem , Benzimidazóis/administração & dosagem , Dinoprosta/análogos & derivados , Hipercolesterolemia/tratamento farmacológico , Hipercolesterolemia/metabolismo , Sinvastatina/administração & dosagem , Adulto , Antioxidantes/administração & dosagem , Selectina E/metabolismo , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , F2-Isoprostanos/metabolismo , Feminino , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Solubilidade , Molécula 1 de Adesão de Célula Vascular/metabolismo , Vitamina E/administração & dosagemRESUMO
AIMS: ß-catenin has been shown to be regulated by inducible nitric oxide synthase (NOS) in endothelial cells. We investigated here whether ß-catenin interacts with and regulates endothelial NOS (eNOS) and whether eNOS activation promotes ß-catenin signalling. METHODS AND RESULTS: We identified ß-catenin as a novel eNOS binding protein in human umbilical vein endothelial cells (HUVECs) by mass spectroscopy and western blot analyses of ß-catenin and eNOS immunoprecipitates. This was confirmed by in situ proximity ligation assay. eNOS activity, assessed by cGMP production and eNOS phosphorylation (Ser1177), was enhanced in ß-catenin(-/-) mouse pulmonary endothelial cells (MPECs) relative to wild-type MPECs. eNOS activation (using adenosine, salbutamol, thrombin, or histamine), or application of an NO donor (spermine NONOate) or cGMP-analogue (8-bromo-cGMP) caused nuclear translocation of ß-catenin in HUVEC as shown by western blotting of nuclear extracts. Exposure to spermine NONOate, 8-bromo-cGMP, or sildenafil (a phosphodiesterase type 5 inhibitor) also increased the expression of ß-catenin-dependent transcripts, IL-8, and cyclin D1. Stimulation of wild-type MPECs with basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), spermine NONOate, 8-bromo-cGMP, or sildenafil increased tube length relative to controls in an angiogenesis assay. These responses were abrogated in ß-catenin(-/-) MPECs, with the exception of that to bFGF which is NO-independent. In C57BL/6 mice, subcutaneous VEGF-supplemented Matrigel plugs containing ß-catenin(-/-) MPECs exhibited reduced angiogenesis compared with plugs containing wild-type MPECs. Angiogenesis was not altered in bFGF-supplemented Matrigel. CONCLUSION: These data reveal bidirectional cross-talk and regulation between the NO-cGMP and ß-catenin signalling pathways.
Assuntos
Células Endoteliais da Veia Umbilical Humana/enzimologia , Neovascularização Fisiológica , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , beta Catenina/metabolismo , Animais , Células Cultivadas , GMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Ativação Enzimática , Ativadores de Enzimas/farmacologia , Quinase 3 da Glicogênio Sintase , Glicogênio Sintase Quinase 3 beta , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Inibidores da Fosfodiesterase 5/farmacologia , Fosforilação , Ligação Proteica , Serina , Transdução de Sinais , beta Catenina/deficiência , beta Catenina/genéticaRESUMO
BACKGROUND: Endothelial dysfunction promotes atherosclerosis. We investigated whether in vivo magnetic resonance imaging (MRI) using an albumin-binding contrast agent, gadofosveset, could monitor the efficacy of minocycline and ebselen in reducing endothelial permeability and atherosclerotic burden in the brachiocephalic artery of high-fat diet (HFD)-fed ApoE-/- mice. METHODS AND RESULTS: ApoE-/- mice were scanned 12 weeks after commencement of either a normal diet (controls) or an HFD. HFD-fed ApoE-/- mice were either untreated or treated with minocycline or ebselen for 12 weeks. Delayed-enhancement MRI and T1 mapping of the brachiocephalic artery, 30 minutes after injection of gadofosveset, showed increased vessel wall enhancement and relaxation rate (R1, s(-1)) in untreated HFD-fed ApoE-/- mice (R1 = 3.8 ± 0.52 s(-1)) compared with controls (R1 = 2.15 ± 0.34 s(-1), P < 0.001). Conversely, minocycline-treated (R1 = 2.7 ± 0.17 s(-1), P < 0.001) and ebselen-treated (R1 = 2.7 ± 0.23 s(-1), P < 0.001) ApoE-/- mice showed less vessel wall enhancement compared with untreated HFD-fed ApoE-/- mice. Mass spectroscopy showed a lower gadolinium concentration in the brachiocephalic artery of treated (minocycline = 28.5 ± 3 µmol/L, ebselen = 32.4 ± 4 µmol/L) compared with untreated HFD-fed ApoE-/- mice (191 ± 4.8 µmol/L) (P < 0.02). Both interventions resulted in a lower plaque burden as measured by delayed-enhancement MRI (minocycline = 0.14 ± 0.02 mm2, ebselen= 0.20 ± 0.09 mm2), untreated = 0.44 ± 0.01 mm2; P < 0.001) and histology (minocycline = 0.13 ± 0.05 mm2, ebselen = 0.18 ± 0.02 mm2, untreated = 0.32 ± 0.04 mm2; P < 0.002). Endothelium cells displayed fewer structural changes and smaller gap junction width in treated compared with untreated animals as seen by electron microscopy (minocycline=42.3 ± 8.4 nm, ebselen = 56.5 ± 17 nm, untreated = 2400 ± 39 nm; P < 0.001). Tissue flow cytometry of the brachiocephalic artery showed lower monocyte/macrophage content in both ebselen- and minocycline-treated mice (8.06 ± 3.2% and 7.62 ± 1.73%, respectively) compared with untreated animals (20.1 ± 2.2%) (P = 0.03), with significant attenuation of the proinflammatory Ly6Chigh subtype (untreated mice, 42.64 ± 6.1% of total monocytes; ebselen, 14.07 ± 9.5% of total monocytes; minocycline, 26.42 ± 0.6% of total monocytes). CONCLUSIONS: We demonstrate that contrast-enhanced MRI with an albumin-binding contrast agent can be used to noninvasively monitor the effect of interventions on endothelial permeability and plaque burden. Blood albumin leakage could be a surrogate marker for the in vivo evaluation of interventions that aim at restoring endothelial integrity.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Aterosclerose/diagnóstico , Aterosclerose/metabolismo , Azóis/farmacologia , Meios de Contraste , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Gadolínio , Imageamento por Ressonância Magnética , Minociclina/farmacologia , Compostos Organometálicos , Compostos Organosselênicos/farmacologia , Albuminas , Animais , Isoindóis , Imageamento por Ressonância Magnética/métodos , Masculino , Camundongos , Permeabilidade/efeitos dos fármacosRESUMO
Over the last two decades or more, anti-platelet therapy has become established as a cornerstone in the treatment of patients with ischaemic cardiovascular disease, since such drugs effectively reduce arterial thrombotic events. The original agent used in this context was aspirin (acetylsalicylic acid) but, with the advent of adenosine diphosphate (ADP) receptor antagonists, the use of dual anti-platelet therapy has resulted in further improvement in cardiovascular outcomes when compared with aspirin alone. The first group of platelet ADP receptor antagonists to be developed was the thienopyridine class, which comprise inactive pro-drugs that require in vivo metabolism to their active metabolites before exerting their inhibitory effect on the P2Y(12) receptor. Clopidogrel has been the principal ADP receptor antagonist in use over the past decade, but is limited by variability in its in vivo inhibition of platelet aggregation (IPA). The pharmacokinetics of clopidogrel are unpredictable due to their vulnerability to multiple independent factors including genetic polymorphisms. Expression of the 3435T/T genetic variant encoding the MDR1 gene for the P-glycoprotein efflux transporter results in a significantly reduced maximum drug concentration and area under the plasma concentration-time curve as intestinal absorption of clopidogrel is reduced; and the expression of the mutant *2 allele of CYP2C19 results in similar pharmacokinetic effects as the two cytochrome P450 (CYP)-mediated steps required for the production of the active metabolite of clopidogrel are impaired. These variable pharmacokinetics lead to erratic pharmacodynamics and cannot reliably be overcome with increased dosing. Both prasugrel, a third-generation thienopyridine, and ticagrelor, a cyto-pentyl-triazolo-pyrimidine, have more predictable pharmacokinetics and enhanced pharmacodynamics than clopidogrel. Neither appears to be affected by the same genetic polymorphisms as clopidogrel; prasugrel requires only a single CYP-mediated step to produce its active metabolite and ticagrelor is not a pro-drug. Enhanced IPA by both prasugrel and ticagrelor is achieved at the expense of increased major bleeding, although this is partially mitigated in the case of ticagrelor due to its reversible IPA. However, the reversible binding of ticagrelor to the P2Y(12) receptor requires a twice-daily dosing regimen. Due to limited data from clinical studies, the use of prasugrel is currently restricted to individuals undergoing percutaneous coronary intervention who are ≤75 years old and have a body weight ≥60 kg. The clinical data for ticagrelor are more comprehensive and this drug therefore has a place in the management of patients with acute coronary syndrome at moderate-to-high risk of ischaemic events, irrespective of treatment strategy. Here we review in detail the pharmacokinetics and pharmacodynamics of clopidogrel, prasugrel and ticagrelor, and explore the implications of the differences in these parameters for their clinical use.
Assuntos
Inibidores da Agregação Plaquetária/farmacologia , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Adenosina/análogos & derivados , Adenosina/farmacologia , Adenosina/uso terapêutico , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/metabolismo , Clopidogrel , Humanos , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêutico , Cloridrato de Prasugrel , Antagonistas do Receptor Purinérgico P2Y/uso terapêutico , Tiofenos/farmacologia , Tiofenos/uso terapêutico , Ticagrelor , Ticlopidina/análogos & derivados , Ticlopidina/farmacologia , Ticlopidina/uso terapêuticoRESUMO
AIMS: Heart failure is associated with deficient endothelial nitric oxide (NO) production as well as increased oxidative stress and accelerated NO degradation. The aim of this study was to evaluate platelet NO biosynthesis and superoxide anion (O(2)(-)) production in patients with heart failure. METHODS AND RESULTS: In platelets from patients with heart failure due to idiopathic dilated cardiomyopathy (n= 16) and healthy control subjects (n= 23), NO synthase (NOS) activity was evaluated by L-[(3)H]-arginine to l-[(3)H]-citrulline conversion, cGMP was determined by radioimmunoassay, vasodilator-stimulated phosphoprotein (VASP: total and serine-239-phosphorylated) was assessed by western blotting, and O(2)(-) production and O(2)(-) scavenging capacity were measured by pholasin-enhanced chemiluminescence. In platelets from patients with heart failure, basal NOS activity was higher than in those from controls; furthermore, whereas platelet NOS activity increased as expected in response to albuterol or collagen in controls, no increase occurred in platelets from heart failure subjects. Despite this, basal intraplatelet NO-attributable cGMP was lower in heart failure than in control subjects, as was serine-239 phosphorylation of VASP, suggesting a decrease in bioactive NO. Platelets from heart failure subjects exhibited higher basal and collagen-stimulated O(2)(-) production and impaired O(2)(-) scavenging capacity, resulting in higher oxidative stress, consistent with the observed decrease in bioactive NO. CONCLUSION: In heart failure, despite activation of NOS, platelets produce less bioactive NO, probably as a result of NO scavenging due to increased O(2)(-) production. This functional defect in the platelet l-arginine/NO/guanylyl cyclase pathway could contribute to the platelet activation observed in heart failure.
Assuntos
Plaquetas/metabolismo , Insuficiência Cardíaca/metabolismo , Óxido Nítrico/fisiologia , Estresse Oxidativo , Transdução de Sinais/fisiologia , Adulto , Moléculas de Adesão Celular/metabolismo , GMP Cíclico/fisiologia , Feminino , Humanos , Masculino , Proteínas dos Microfilamentos/metabolismo , Pessoa de Meia-Idade , Óxido Nítrico Sintase/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Superóxidos/metabolismoRESUMO
BACKGROUND: Activated platelets exert a pro-inflammatory action that can be largely ascribed to their ability to interact with leukocytes and modulate their activity. We hypothesized that platelet activation and consequent formation of monocyte-platelet aggregates (MPA) induces a pro-inflammatory phenotype in circulating monocytes. METHODOLOGY/PRINCIPAL FINDINGS: CD62P(+) platelets and MPA were measured, and monocytes characterized, by whole blood flow cytometry in healthy subjects, before and two days after receiving influenza immunization. Three monocytic subsets were identified: CD14(+)CD16(-), CD14(high)CD16(+)and CD14(low)CD16(+). The increase in high sensitivity C-reactive protein post-immunization was accompanied by increased platelet activation and MPA formation (25.02±12.57 vs 41.48±16.81; pâ=â0.01), along with enhancement of circulating CD14(high)CD16(+) cells (4.7±3.6 vs 10.4±4.8; pâ=â0.003), their percentage being linearly related to levels of CD62P(+)-platelets (r(2)â=â0.4347; pâ=â0.0008). In separate in vitro experiments, co-incubation of CD14(+)CD16(-) cells, isolated from healthy donor subjects, with autologous platelets gave rise to up-regulation of CD16 on monocytes as compared with those maintained in medium alone (% change in CD14(+)CD16(+) cells following 48 h co-incubation of monocytes with platelets was +106±51% vs monocytes in medium alone; p<0.001). This effect correlated directly with degree of MPA formation (r(2)â=â0.7731; p<0.0001) and was associated with increased monocyte adhesion to endothelial cells. P-selectin glycoprotein ligand-1 (PSGL-1) blocking antibody, which abrogates MPA formation, abolished these effects, as did the cyclooxygenase (COX)-2 selective inhibitor NS-398, aspirin and the EP1/EP2-selective antagonist AH6809. CONCLUSIONS/SIGNIFICANCE: These data suggest that MPA formation, as occurs in the blood under pro-inflammatory conditions, expands the pool of circulating CD14(high)CD16(+) monocytes in a COX-2 dependent manner, and these monocytes exhibit increased adhesion to endothelium. Our findings delineate a novel mechanism underlying the pro-inflammatory effect of platelet activation.
Assuntos
Plaquetas/patologia , Comunicação Celular , Movimento Celular , Inflamação/patologia , Monócitos/patologia , Adulto , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Agregação Celular/efeitos dos fármacos , Comunicação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/biossíntese , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , Humanos , Imunização , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Receptores de Lipopolissacarídeos/metabolismo , Masculino , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Fenótipo , Ativação Plaquetária/efeitos dos fármacos , Adesividade Plaquetária/efeitos dos fármacos , Receptores de IgG/metabolismoRESUMO
Essential hypertension is associated with increased risk of arterial thrombotic disease. Among other factors, enhanced platelet activity contributes significantly to this phenomenon. An increased level of circulating monocyte-platelet aggregates (MPAs) represents one of the most robust markers of platelet activation; furthermore, these aggregates are also believed to contribute to the pathophysiology of atherothrombotic disease. Putative mechanisms that contribute to platelet activation in essential hypertension include endothelial dysfunction, neurohumoral (sympathetic and renin-angiotensin systems) overactivity, decreased platelet nitric oxide (NO) biosynthesis, and platelet degranulation secondary to increased shear. Current recommendations are that hypertensive patients receive aspirin therapy only if their calculated cardiovascular risk is high and their blood pressure (BP) is adequately controlled. By contrast, the use of antiplatelet treatment in low-risk hypertensive patients is not established and merits further investigation. Moreover, the place of alternative antiplatelet agents other than aspirin, such as clopidogrel, is unclear at present. Some experimental evidence suggests that clopidogrel may confer an additive protective effect over and above aspirin in hypertensive patients, by virtue of effects on the evolution of the atherosclerotic process. This now needs to be investigated in long-term clinical outcome studies.
Assuntos
Transtornos Plaquetários/tratamento farmacológico , Plaquetas/efeitos dos fármacos , Hipertensão/sangue , Ativação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/uso terapêutico , Trombose/tratamento farmacológico , Anti-Hipertensivos/efeitos adversos , Anti-Hipertensivos/uso terapêutico , Transtornos Plaquetários/etiologia , Clopidogrel , Humanos , Hipertensão/complicações , Ativação Plaquetária/fisiologia , Trombose/etiologia , Ticlopidina/análogos & derivados , Ticlopidina/uso terapêuticoRESUMO
Atherosclerotic plaque plays a crucial role for the development of ischaemic diseases and, therefore, its early diagnosis and feature can help to reduce the incidence of cardiovascular events. Detection of early atherogenesis and characterization of plaque feature are the major end-points of research in cardiovascular imaging. Different techniques have been proposed as instrument for morphological and functional study of vascular walls. The purpose of this review is to underline the possibility of in vivo detecting the different stages of atherogenesis by using imaging techniques as well as their relationship with other risk factors in an attempt to assess the meaning of vascular lesions. Very promising results seem to emerge by the analysis of the literature on the subject, although different patterns are yet to be clarified.