RESUMEN
The study aimed to evaluate the antithrombotic action of Acrocomia aculeata pulp oil (AAPO) in natura, in an in vitro experimental model. AAPO was obtained by solvent extraction, and its chemical characterization was performed by gas chromatography coupled to a mass spectrometer (GC-MS). In vitro toxicity was evaluated with the Trypan Blue exclusion test and in vivo by the Galleria mellonella model. ADP/epinephrine-induced platelet aggregation after treatment with AAPO (50, 100, 200, 400, and 800 µg/mL) was evaluated by turbidimetry, and coagulation was determined by prothrombin activity time (PT) and activated partial thromboplastin time (aPTT). Platelet activation was measured by expression of P-selectin on the platelet surface by flow cytometry and intraplatelet content of reactive oxygen species (ROS) by fluorimetry. The results showed that AAPO has as major components such as oleic acid, palmitic acid, lauric acid, caprylic acid, and squalene. AAPO showed no toxicity in vitro or in vivo. Platelet aggregation decreased against agonists using treatment with different concentrations of AAPO. Oil did not interfere in PT and aPTT. Moreover, it expressively decreased ROS-induced platelet activation and P-selectin expression. Therefore, AAPO showed antiplatelet action since it decreased platelet activation verified by the decrease in P-selectin expression as well as in ROS production.
Asunto(s)
Fibrinolíticos , Selectina-P , Aceites de Plantas , Agregación Plaquetaria , Especies Reactivas de Oxígeno , Animales , Agregación Plaquetaria/efectos de los fármacos , Selectina-P/metabolismo , Humanos , Aceites de Plantas/farmacología , Aceites de Plantas/química , Especies Reactivas de Oxígeno/metabolismo , Fibrinolíticos/farmacología , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Coagulación Sanguínea/efectos de los fármacos , Activación Plaquetaria/efectos de los fármacosRESUMEN
Clopidogrel is widely used worldwide as an antiplatelet therapy in patients with acute coronary disease. Genetic factors influence interindividual variability in response. Some studies have explored the polygenic contributions in the drug response, generating pharmacogenomic risk scores (PgxPRS). Importantly, these factors are less explored in underrepresented populations, such as Latin-American countries. Identifying patients at risk of high-on-treatment platelet reactivity (HTPR) is highly valuable in translational medicine. In this study we used a custom next-generation sequencing (NGS) panel composed of 91 single nucleotide polymorphisms (SNPs) and 28 genes related to clopidogrel metabolism, to analyze 70 patients with platelet reactivity values, assessed through closure time (CT). Our results demonstrated the association of SNPs with HTPR and non-HTPR, revealing the strongest associations with rs2286823 (OR: 5,0; 95% CI: 1,02-24,48; p: 0,03), rs2032582 (OR: 4,41; 95% CI: 1,20-16,12; p: 0,019), and rs1045642 (OR: 3,38; 95% CI: 0,96-11,9; p: 0,05). Bivariate regression analysis demonstrated the significant association of several SNPs with the CT value, a "surrogate" biomarker of clopidogrel response. Exploratory results from the LASSO regression model showed a high discriminatory capacity between HTPR and non-HTPR patients (AUC: 0,955), and the generated PgxPRS demonstrated a significant negative association between the risk score, CT value, and the condition of HTPR and non-HTPR. To our knowledge, our study addresses for the first time the analysis of the polygenic contribution in platelet reactivity using NGS and establishes PgxPRS derived from the LASSO model. Our results demonstrate the polygenic implication of clopidogrel response and offer insights applicable to the translational medicine of antiplatelet therapy in an understudied population.
Asunto(s)
Plaquetas , Clopidogrel , Secuenciación de Nucleótidos de Alto Rendimiento , Inhibidores de Agregación Plaquetaria , Polimorfismo de Nucleótido Simple , Humanos , Clopidogrel/uso terapéutico , Clopidogrel/farmacología , Masculino , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Femenino , Inhibidores de Agregación Plaquetaria/uso terapéutico , Inhibidores de Agregación Plaquetaria/farmacología , Persona de Mediana Edad , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Anciano , Herencia Multifactorial/genética , Ticlopidina/análogos & derivados , Ticlopidina/uso terapéutico , Ticlopidina/farmacologíaRESUMEN
Gamma-terpinene (γ-TPN) is a cyclohexane monoterpene isolated from plant essential oils, such as tea tree (Melaleuca alternifolia), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris Marchand), and eucalyptus (Eucalyptus sp.). Terpenes are widely studied molecules pharmacologically active on the cardiovascular system, hemostasis, and antioxidant actions. Herein, it was investigated the cytotoxic and antiplatelet activity of γ-TPN using different non-clinical laboratory models. For in silico evaluation, the PreADMET, SwissADME, and SwissTargetPrediction softwares were used. Molecular docking was performed using the AutoDockVina and BIOVIA Discovery Studio databases. The cytotoxicity of γ-TPN was analyzed by the MTT assay upon normal murine endothelial SVEC4-10 and fibroblast L-929 cells. Platelet aggregation was evaluated with platelet-rich (PRP) and platelet-poor (PPP) plasma from spontaneously hypertensive rats (SHR), in addition to SVEC4-10 cells pre-incubated with γ-TPN (50, 100, and 200 µM) for 24 h. SHR animals were pre-treated by gavage with γ-TPN for 7 days and divided into four groups (negative control, 25, 50, and 100 mg/kg). Blood samples were collected to measure nitrite using the Griess reagent. Gamma-TPN proved to be quite lipid-soluble (Log P = +4.50), with a qualified profile of similarity to the drug, good bioavailability, and adequate pharmacokinetics. It exhibited affinity mainly for the P2Y12 receptor (6.450 ± 0.232 Kcal/mol), moderate cytotoxicity for L-929 (CC50 = 333.3 µM) and SVEC 4-10 (CC50 = 366.7 µM) cells. The presence of γ-TPN in SVEC 4-10 cells was also able to reduce platelet aggregation by 51.57 and 44.20% at lower concentrations (50 and 100 µM, respectively). Then, γ-TPN has good affinity with purinergic receptors and an effect on the reversal of platelet aggregation and oxidative stress, being promising and safe for therapeutic targets and subsequent studies on the control of thromboembolic diseases.
Asunto(s)
Monoterpenos Ciclohexánicos , Simulación del Acoplamiento Molecular , Inhibidores de Agregación Plaquetaria , Agregación Plaquetaria , Ratas Endogámicas SHR , Animales , Ratones , Agregación Plaquetaria/efectos de los fármacos , Monoterpenos Ciclohexánicos/farmacología , Inhibidores de Agregación Plaquetaria/farmacología , Masculino , Línea Celular , Ratas , Ratas Wistar , Supervivencia Celular/efectos de los fármacos , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Monoterpenos/farmacologíaRESUMEN
Platelets are the critical target for preventing and treating pathological thrombus formation. However, despite current antiplatelet therapy, cardiovascular mortality remains high, and cardiovascular events continue in prescribed patients. In this study, first results were obtained with ortho-carbonyl hydroquinones as antiplatelet agents; we found that linking triphenylphosphonium cation to a bicyclic ortho-carbonyl hydroquinone moiety by a short alkyl chain significantly improved their antiplatelet effect by affecting the mitochondrial functioning. The mechanism of action involves uncoupling OXPHOS, which leads to an increase in mitochondrial ROS production and a decrease in the mitochondrial membrane potential and OCR. This alteration disrupts the energy production by mitochondrial function necessary for the platelet activation process. These effects are responsive to the complete structure of the compounds and not to isolated parts of the compounds tested. The results obtained in this research can be used as the basis for developing new antiplatelet agents that target mitochondria.
Asunto(s)
Plaquetas , Hidroquinonas , Potencial de la Membrana Mitocondrial , Compuestos Organofosforados , Inhibidores de Agregación Plaquetaria , Humanos , Plaquetas/metabolismo , Plaquetas/efectos de los fármacos , Hidroquinonas/farmacología , Hidroquinonas/química , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Compuestos Organofosforados/farmacología , Compuestos Organofosforados/química , Fosforilación Oxidativa/efectos de los fármacos , Activación Plaquetaria/efectos de los fármacos , Agregación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Inhibidores de Agregación Plaquetaria/química , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic process regulated by different signaling networks. Therefore, there are now focused efforts to search for novel bioactive compounds which target receptors and pathways in the platelet activation process while preserving normal hemostatic function. The antiplatelet activity of numerous fruits and vegetables and their multiple mechanisms of action have recently been highlighted. In this review, we review the antiplatelet actions of bioactive compounds via key pathways (protein disulfide isomerase, mitogen-activated protein kinases, mitochondrial function, cyclic adenosine monophosphate, Akt, and shear stress-induced platelet aggregation) with no effects on bleeding time. Therefore, targeting these pathways might lead to the development of effective antiplatelet strategies that do not increase the risk of bleeding.
Asunto(s)
Plaquetas/metabolismo , Hemorragia/prevención & control , Fitoquímicos/uso terapéutico , Activación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Agregación Plaquetaria/efectos de los fármacos , Trombosis/tratamiento farmacológico , Animales , Plaquetas/efectos de los fármacos , Hemorragia/metabolismo , Hemostasis/efectos de los fármacos , Humanos , Fitoquímicos/farmacología , Placa Aterosclerótica/metabolismo , Inhibidores de Agregación Plaquetaria/farmacología , Trombosis/metabolismoAsunto(s)
Plaquetas/fisiología , Proteínas Activadoras de GTPasa/genética , Megacariocitos/citología , Regulación hacia Arriba , Animales , Plaquetas/efectos de los fármacos , Diferenciación Celular , Línea Celular , Linaje de la Célula , Células Cultivadas , Proteínas Activadoras de GTPasa/metabolismo , Silenciador del Gen , Humanos , Megacariocitos/efectos de los fármacos , Megacariocitos/metabolismo , Ratones , Selectina-P/farmacología , Agregación Plaquetaria/efectos de los fármacos , Cultivo Primario de Células , Trombina/farmacologíaRESUMEN
Air pollution is a worldwide public health issue and it is associated with millions of premature deaths due to cancer, thrombosis, and pulmonary and cardiovascular diseases. Thrombosis is the excessive clotting that blocks a blood vessel, and its etiology is multifactorial. In recent years, growing evidence has linked air pollution, especially particulate matter (PM) and metals, to the development of thrombosis. PM and metals induce lung and systemic inflammation and oxidative stress that are frequent mechanisms in thrombosis. Platelets are important effectors of physiological hemostasis and pathological thrombosis. They are responsible for the formation of the initial plug and are important in the cellular model of coagulation. Therefore, any changes in their morphology or function or an increase in activation could be extremely relevant in thrombosis. Megakaryocytes (MKs) in the bone marrow and in the lungs are the precursor cells of platelets, and the latter is the first organ injured by air pollution. There is substantial evidence of the effect that PM and metals have on platelets, but there is almost no research about the effect of PM and metals on MKs. It is very likely that the alterations produced by air pollution originate in these cells. In this article, we review the biology of MKs and platelets and their role in particulate air pollution-related thrombosis to emphasize the need for further research in this field.
Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Plaquetas/efectos de los fármacos , Megacariocitos/efectos de los fármacos , Material Particulado/efectos adversos , Trombosis/etiología , Plaquetas/metabolismo , Humanos , Trombosis/inducido químicamenteRESUMEN
Platelets are the smallest blood cells, and their activation (platelet cohesion or aggregation) at sites of vascular injury is essential for thrombus formation. Since the use of antiplatelet therapy is an unsolved problem, there are now focused and innovative efforts to develop novel antiplatelet compounds. In this context, we assessed the antiplatelet effect of an acylhydroquinone series, synthesized by Fries rearrangement under microwave irradiation, evaluating the effect of diverse acyl chain lengths, their chlorinated derivatives, and their dimethylated derivatives both in the aromatic ring and also the effect of the introduction of a bromine atom at the terminus of the acyl chain. Findings from a primary screening of cytotoxic activity on platelets by lactate dehydrogenase assay identified 19 non-toxic compounds from the 27 acylhydroquinones evaluated. A large number of them showed IC50 values less than 10 µM acting against specific pathways of platelet aggregation. The highest activity was obtained with compound 38, it exhibited sub-micromolar IC50 of 0.98 ± 0.40, 1.10 ± 0.26, 3.98 ± 0.46, 6.79 ± 3.02 and 42.01 ± 3.48 µM against convulxin-, collagen-, TRAP-6-, PMA- and arachidonic acid-induced platelet aggregation, respectively. It also inhibited P-selectin and granulophysin expression. We demonstrated that the antiplatelet mechanism of compound 38 was through a decrease in a central target in human platelet activation as in mitochondrial function, and this could modulate a lower response of platelets to activating agonists. The results of this study show that the chemical space around ortho-carbonyl hydroquinone moiety is a rich source of biologically active compounds, signaling that the acylhydroquinone scaffold has a promising role in antiplatelet drug research.
Asunto(s)
Plaquetas/efectos de los fármacos , Hidroquinonas/química , Hidroquinonas/farmacología , Inhibidores de Agregación Plaquetaria/química , Inhibidores de Agregación Plaquetaria/farmacología , Plaquetas/fisiología , Humanos , Agregación Plaquetaria/efectos de los fármacos , Agregación Plaquetaria/fisiología , Relación Estructura-ActividadRESUMEN
Platelet activation plays a key role in cardiovascular diseases. The generation of mitochondrial reactive oxygen species (ROS) has been described as a critical step required for platelet activation. For this reason, it is necessary to find new molecules with antiplatelet activity and identify their mechanisms of action. Mitoquinone (MitoQ) is a mitochondria-targeted antioxidant that reduces mitochondrial overproduction of ROS. In this work, the antiplatelet effect of MitoQ through platelet adhesion and spreading, secretion, and aggregation was evaluated. Thus MitoQ, in a non-toxic effect, decreased platelet adhesion and spreading on collagen surface, and expression of P-selectin and CD63, and inhibited platelet aggregation induced by collagen, convulxin, thrombin receptor activator peptide-6 (TRAP-6), and phorbol 12-myristate 13-acetate (PMA). As an antiplatelet mechanism, we showed that MitoQ produced mitochondrial depolarization and decreased ATP secretion. Additionally, in platelets stimulated with antimycin A and collagen MitoQ significantly decreased ROS production. Our findings showed, for the first time, an antiplatelet effect of MitoQ that is probably associated with its mitochondrial antioxidant effect.
Asunto(s)
Antioxidantes/farmacología , Plaquetas/metabolismo , Compuestos Organofosforados/farmacología , Especies Reactivas de Oxígeno/metabolismo , Ubiquinona/análogos & derivados , Adenosina Trifosfato/metabolismo , Animales , Plaquetas/efectos de los fármacos , Células Cultivadas , Colágeno/metabolismo , Humanos , Ratones , Mitocondrias/metabolismo , Oligopéptidos/farmacología , Selectina-P/metabolismo , Ésteres del Forbol/farmacología , Activación Plaquetaria/efectos de los fármacos , Tetraspanina 30/metabolismo , Ubiquinona/farmacologíaRESUMEN
PURPOSE: Hyperlipidemia, characterized by an increase in circulating lipid levels, doubles the chance of developing cardiovascular diseases. It prompts inflammation, immune activation, and oxidative stress in the bloodstream and organs of rats. Thus, we theorized that the metabolism of purines, an immunomodulatory mechanism, is altered in cells involved in the development of cardiovascular diseases. METHODS: Therefore, we induced acute hyperlipidemia in Wistar rats with Poloxamer-407 and euthanized the animals 36 h later. The leucocyte differential, the rate of purine metabolism on the surface of platelets and heart cells, and markers of oxidative stress in the heart tissue were evaluated. These parameters were also assessed in animals pretreated for 30 days with curcumin and/or rutin. RESULTS: Hyperlipidemia increased the hydrolyses of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in platelets. In heart cells, the metabolism of ATP and adenosine (ADO) were increased, while ADP hydrolysis was reduced. Additionally, lipid damage and antioxidant defenses were increased in heart homogenates. Hyperlipidemic rats also exhibited a reduced percentage of eosinophils and lymphocytes. CONCLUSION: Together, these findings are indicative of an increased risk of developing cardiovascular diseases in hyperlipidemic rats. The pretreatments with antioxidants reverted some of the changes prompted by hyperlipidemia preventing detrimental changes in the cells and tissues. Graphical Abstract.
Asunto(s)
Plaquetas/metabolismo , Hiperlipidemias/metabolismo , Miocitos Cardíacos/metabolismo , Estrés Oxidativo , Purinas/metabolismo , Animales , Antioxidantes/farmacología , Plaquetas/efectos de los fármacos , Curcumina/farmacología , Modelos Animales de Enfermedad , Eosinófilos/metabolismo , Hidrólisis , Hiperlipidemias/tratamiento farmacológico , Hiperlipidemias/etiología , Peroxidación de Lípido , Linfocitos/metabolismo , Masculino , Miocitos Cardíacos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Poloxámero , Ratas Wistar , Rutina/farmacologíaRESUMEN
Atherosclerosis is a multifactorial chronic disease, initiated by an endothelial dysfunction. Adenosine and its analogs can change a variety of inflammatory diseases and has shown important effects at different disease models. Inosine is a stable analogous of adenosine, but its effects in inflammatory diseases, like atherosclerosis, have not yet been studied. The aim of this study was to evaluate the pharmacological properties of inosine, administered sub chronically in a hypercholesterolemic model. Male Wistar rats were divided into four groups: control group (C) and control + inosine (C + INO) received standard chow, hypercholesterolemic diet group (HCD) and HCD + inosine (HCD + INO) were fed a hypercholesterolemic diet. At 31st experimentation day, the treatment with inosine was performed for C + INO and HCD + INO groups once daily in the last 15 days. We observed that the hypercholesterolemic diet promoted an increase in lipid levels and inflammatory cytokines production, while inosine treatment strongly decreased these effects. Additionally, HCD group presented a decrease in maximum relaxation acetylcholine induced and an increase in contractile response phenylephrine induced when compared to the control group, as well as it has presented an enhancement in collagen and ADP-induced platelet aggregation. On the other hand, inosine treatment promoted a decrease in contractile response to phenylephrine, evoked an improvement in endothelium-dependent vasorelaxant response and presented antiplatelet properties. Moreover, inosine activated eNOS and reduced p38 MAPK/NF-κB pathway in aortic tissues. Taken together, the present results indicate inosine as a potential drug for the treatment of cardiovascular disorders such as atherosclerosis.
Asunto(s)
Antiinflamatorios/uso terapéutico , Aterosclerosis/tratamiento farmacológico , Inosina/uso terapéutico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Vasodilatadores/uso terapéutico , Animales , Antiinflamatorios/farmacología , Aorta Torácica/efectos de los fármacos , Aorta Torácica/fisiología , Aterosclerosis/sangre , Aterosclerosis/metabolismo , Plaquetas/efectos de los fármacos , Plaquetas/fisiología , Humanos , Inosina/farmacología , Interleucina-6/sangre , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , FN-kappa B/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Agregación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Ratas Wistar , Factor de Necrosis Tumoral alfa/sangre , Vasodilatadores/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
G protein-coupled receptors are critical mediators of platelet activation whose signaling can be modulated by members of the regulator of G protein signaling (RGS) family. The 2 most abundant RGS proteins in human and mouse platelets are RGS10 and RGS18. While each has been studied individually, critical questions remain about the overall impact of this mode of regulation in platelets. Here, we report that mice missing both proteins show reduced platelet survival and a 40% decrease in platelet count that can be partially reversed with aspirin and a P2Y12 antagonist. Their platelets have increased basal (TREM)-like transcript-1 expression, a leftward shift in the dose/response for a thrombin receptor-activating peptide, an increased maximum response to adenosine 5'-diphosphate and TxA2, and a greatly exaggerated response to penetrating injuries in vivo. Neither of the individual knockouts displays this constellation of findings. RGS10-/- platelets have an enhanced response to agonists in vitro, but platelet count and survival are normal. RGS18-/- mice have a 15% reduction in platelet count that is not affected by antiplatelet agents, nearly normal responses to platelet agonists, and normal platelet survival. Megakaryocyte number and ploidy are normal in all 3 mouse lines, but platelet recovery from severe acute thrombocytopenia is slower in RGS18-/- and RGS10-/-18-/- mice. Collectively, these results show that RGS10 and RGS18 have complementary roles in platelets. Removing both at the same time discloses the extent to which this regulatory mechanism normally controls platelet reactivity in vivo, modulates the hemostatic response to injury, promotes platelet production, and prolongs platelet survival.
Asunto(s)
Plaquetas/metabolismo , Activación Plaquetaria/genética , Proteínas RGS/genética , Trombopoyesis/genética , Animales , Plaquetas/efectos de los fármacos , Supervivencia Celular/genética , Ratones , Ratones Noqueados , Fosforilación , Factor de Activación Plaquetaria/farmacología , Activación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Recuento de Plaquetas , Proteínas RGS/metabolismo , Trombopoyesis/efectos de los fármacosRESUMEN
Aging is one of the main risk factors for the development of chronic diseases, with both the vascular endothelium and platelets becoming functionally altered. Cellular senescence is a form of permanent cell cycle arrest initially described in primary cells propagated in vitro, although it can also be induced by anticancer drugs and other stressful stimuli. Attesting for the complexity of the senescent phenotype, senescent cells synthesize and secrete a wide variety of bioactive molecules. This "senescence-associated secretory phenotype" (SASP) endows senescent cells with the ability to modify the tissue microenvironment in ways that may be relevant to the development of various physiological and pathological processes. So far, however, the direct role of factors secreted by senescent endothelial cells on platelet function remains unknown. In the present work, we explore the effects of SASP factors derived from senescent endothelial cells on platelet function. To this end, we took advantage of a model in which immortalized endothelial cells (HMEC-1) were induced to senesce following exposure to doxorubicin, a chemotherapeutic drug widely used in the clinic. Our results indicate that (1) low concentrations of doxorubicin induce senescence in HMEC-1 cells; (2) senescent HMEC-1 cells upregulate the expression of selected components of the SASP and (3) the media conditioned by senescent endothelial cells are capable of inducing platelet activation and aggregation. These results suggest that factors secreted by senescent endothelial cells in vivo could have a relevant role in the platelet activation observed in the elderly or in patients undergoing therapeutic stress.
Asunto(s)
Senescencia Celular , Células Endoteliales/metabolismo , Activación Plaquetaria , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Comunicación Celular , Línea Celular , Células Cultivadas , Medios de Cultivo Condicionados/farmacología , Células Endoteliales/fisiología , HumanosRESUMEN
OBJECTIVE: To examine the efficiency of hemoperfusion in removing South American rattlesnake (Crotalus durissus terrificus) venom from rats compared with neutralization by antivenom. DESIGN: An exploratory experimental investigation in rats involving the injection of snake venom with or without subsequent hemoperfusion or antivenom administration. SETTING: Basic animal research laboratory in a private university. ANIMALS: Normal, healthy male Wistar rats (0.29-0.40 kg, 3-6 months old) from a commercial breeder. INTERVENTIONS: Four experimental groups of randomly allocated rats (n = 3/group) were studied: Group 1: rats were injected with a single dose of venom (5 mg/kg, IM, in the right thigh) with no other treatment; blood samples were collected minutes before death to determine leukocyte, platelet, and erythrocyte counts; Group 2 (Control): rats underwent hemoperfusion alone for 60 min using a hemoperfusion cartridge designed for protein adsorption (by granulated charcoal) and protein precipitation (by tannic acid); Group 3 (Venom + antivenom): rats were injected with venom (5 mg/kg, IM) and, 10 min later, were treated with antivenom at the venom:antivenom ratio recommended by the manufacturer; Group 4 (Venom + hemoperfusion): Rats were injected with venom (5 mg/kg, IM) and, 10 min later, were hemoperfused for 60 min. In groups 2-4, blood samples were collected for leukocyte, platelet, and erythrocyte counts 24 h after venom. MEASUREMENTS AND MAIN RESULTS: Rats injected with venom alone (Group 1) developed signs of neurotoxicity and ataxia and died in 9.0 ± 0.43 h but showed no changes in leukocyte or erythrocyte counts. In contrast, there were no deaths in groups 2-4. The lack of deaths in Groups 3 and 4 indicated that antivenom and hemoperfusion, respectively, protected against the lethal effects of the venom. CONCLUSIONS: Hemoperfusion with a double-action hemoperfusion cartridge capable of protein adsorption and precipitation protected rats against C. d. terrificus venom.
Asunto(s)
Venenos de Crotálidos , Hemoperfusión/métodos , Animales , Antivenenos/uso terapéutico , Plaquetas/efectos de los fármacos , Crotalus , Masculino , Ratas , Ratas WistarRESUMEN
Objective: To demonstrate the utility of dexamethasone, used according to the criteria of the attending physician, in patients with HELLP syndrome.Methods: This cross-sectional study was conducted in patients with HELLP syndrome and was based on the daily, real-life management of HELLP syndrome. Patients who received dexamethasone had it administered immediately after giving birth at a dosage of 8 mg every 8 hours for 72 hours, for a total of 72 mg. The analysis was conducted between patients who received corticosteroids and those who did not, with complete or partial HELLP.Results: There were 97 women who suffered complications from HELLP syndrome, there were 43 (44.3%) received dexamethasone. The groups were comparable except for the initial platelet count because this was the criterion used to divide the groups. In addition, the group without corticosteroids comprised more patients with partial HELLP. The platelet count shows that on the third day was similar in both groups, following a difference of more than 40,000 at the beginning of the study. The average platelet increase was 27,448 in the group without corticosteroids and 88,408 in the corticosteroid group; p = .001.Conclusions: This study demonstrates that the administration of postpartum dexamethasone at a dosage of 8 mg every 8 hours for 72 hours in HELLP syndrome is associated with a significant increase in platelet count.
Asunto(s)
Dexametasona/uso terapéutico , Síndrome HELLP/tratamiento farmacológico , Adulto , Plaquetas/efectos de los fármacos , Plaquetas/patología , Bolivia/epidemiología , Estudios Transversales , Dexametasona/administración & dosificación , Esquema de Medicación , Femenino , Síndrome HELLP/epidemiología , Humanos , Recuento de Plaquetas , Atención Posnatal/métodos , Periodo Posparto/sangre , Periodo Posparto/efectos de los fármacos , Pautas de la Práctica en Medicina/estadística & datos numéricos , Embarazo , Resultado del Tratamiento , Adulto JovenRESUMEN
Atroxlysin-III (Atr-III) was purified from the venom of Bothrops atrox. This 56-kDa protein bears N-linked glycoconjugates and is a P-III hemorrhagic metalloproteinase. Its cDNA-deduced amino acid sequence reveals a multidomain structure including a proprotein, a metalloproteinase, a disintegrin-like and a cysteine-rich domain. Its identity with bothropasin and jararhagin from Bothrops jararaca is 97% and 95%, respectively. Its enzymatic activity is metal ion-dependent. The divalent cations, Mg2+ and Ca2+, enhance its activity, whereas excess Zn2+ inhibits it. Chemical modification of the Zn2+-complexing histidine residues within the active site by using diethylpyrocarbonate (DEPC) inactivates it. Atr-III degrades plasma fibronectin, type I-collagen, and mainly the α-chains of fibrinogen and fibrin. The von Willebrand factor (vWF) A1-domain, which harbors the binding site for GPIb, is not hydrolyzed. Platelets interact with collagen via receptors for collagen, glycoprotein VI (GPVI), and α2ß1 integrin. Neither the α2ß1 integrin nor its collagen-binding A-domain is fragmented by Atr-III. In contrast, Atr-III cleaves glycoprotein VI (GPVI) into a soluble ~55-kDa fragment (sGPVI). Thereby, it inhibits aggregation of platelets which had been stimulated by convulxin, a GPVI agonist. Selectively, Atr-III targets GPVI antagonistically and thus contributes to the antithrombotic effect of envenomation by Bothrops atrox.
Asunto(s)
Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Venenos de Crotálidos/enzimología , Crotalinae , Metaloproteasas/farmacología , Glicoproteínas de Membrana Plaquetaria/biosíntesis , Secuencia de Aminoácidos , Animales , Crotalinae/metabolismo , Matriz Extracelular , Metaloproteasas/química , Metaloproteasas/genética , Metaloproteasas/aislamiento & purificación , Modelos Moleculares , Filogenia , Glicoproteínas de Membrana Plaquetaria/antagonistas & inhibidores , Glicoproteínas de Membrana Plaquetaria/química , Conformación Proteica , Proteolisis , Relación Estructura-ActividadRESUMEN
Abstract Background: High platelet reactivity (HPR) during therapy with acetylsalicylic acid (ASA) is a poor prognostic factor in acute coronary syndromes (ACS). The prevalence of HPR during ACS is greater than that reported in stable diseases. However, it is unclear whether this prevalence of HPR is a transient phenomenon or a characteristic of this high-risk population. Objective: The main objective is to compare the effects of ASA on platelet function in the initial and late phases of ACS in a single population. Secondary objectives are: correlation between the tests between themselves and the relationship between the tests and the variation of the inflammatory markers (C-reactive protein and interleukin-6). Methods: Seventy patients with non-ST segment elevation (NSTE) ACS in use of 100-200 mg of ASA per day for at least 7 days were prospectively studied. Platelet function was assessed in the first 48 hours and subsequently after 3 months using four methods: VerifyNow™ (VFN), whole blood platelet aggregation (WBPA) with arachidonic acid (AA) and collagen as agonists, and platelet function analyzer (PFA). The level of statistical significance considered was < 0.05. Results: According to the more specific methods (WBPA with AA and VFN), the incidence of HPR was significantly higher in the early phase than in the late phase: WBPA with AA: 31% versus 13%, p = 0.015; VFN: 32% versus 16%, p = 0.049. The other methods tested, which were less specific for ASA, did not show significant differences between phases. The correlation between the methods was weak or moderate (r ranging from 0.3 to 0.5, p < 0.05), and there were no significant associations between HPR and inflammatory markers. Conclusion: The prevalence of HPR during AAS therapy, assessed by specific methods for cyclooxygenase 1 (COX-1), is higher during the acute phase than in the late phase of NSTE ACS.
Resumo Fundamento: A alta atividade plaquetária (AAP) durante a terapia com ácido acetilsalicílico (AAS) é fator de mau prognóstico nas síndromes coronarianas agudas (SCA). A prevalência de AAP durante a SCA é maior do que a relatada na doença estável. No entanto, não está claro se esta prevalência de AAP é um fenômeno transitório ou característica dessa população de alto risco. Objetivo: O objetivo principal é comparar, em uma mesma população, os efeitos do AAS sobre a função plaquetária nas fases inicial e tardia da SCA. Os objetivos secundários são: correlação entre os testes entre si e a relação entre os testes e a variação dos marcadores inflamatórios (proteína C reativa e interleucina-6). Métodos: Foram estudados prospectivamente 70 pacientes com SCA sem elevação de ST (SCSST) em uso de 100 a 200 mg de AAS por dia por pelo menos 7 dias. A função plaquetária foi avaliada nas primeiras 48 horas e 3 meses após por quatro métodos: VerifyNow™ (VFN), agregometria de sangue total (AST) com ácido araquidônico (AA) e colágeno como agonistas, e analisador de função plaquetária (PFA). O nível de significância estatístico considerado foi < 0,05. Resultados: A média de idade foi de 65 ±9,7 anos e 54% da população eram do sexo feminino. De acordo com os métodos mais específicos (AST com AA e VFN), a incidência de AAP foi significativamente maior na fase inicial, em relação à tardia: AST com AA 31% versus 13%, p = 0,015; VFN 32% versus 16%, p = 0,049. Os outros métodos testados, menos específicos para o AAS, não mostraram diferenças significativas entre as fases. A correlação entre os métodos foi fraca ou moderada (r variando de 0,3 a 0,5, p < 0,05), e não houve associações significativas entre AAP e marcadores inflamatórios. Conclusão: A prevalência de AAP durante a terapia com AAS, avaliada por métodos específicos para cicloxigenase 1 (COX-1), é maior durante a fase aguda do que na tardia da SCASST.
Asunto(s)
Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Plaquetas/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Aspirina/uso terapéutico , Síndrome Coronario Agudo/tratamiento farmacológico , Pruebas de Función Plaquetaria , Trastornos de las Plaquetas Sanguíneas/tratamiento farmacológico , Plaquetas/metabolismo , Inhibidores de Agregación Plaquetaria/farmacología , Aspirina/farmacología , Estudios Prospectivos , Factores de Riesgo , Infarto del Miocardio sin Elevación del ST/fisiopatologíaRESUMEN
BACKGROUND: Platelet Toll-like receptor (TLR)2/4 are key players in amplifying the host immune response; however, their role in human megakaryo/thrombopoiesis has not yet been defined. OBJECTIVES: We evaluated whether Pam3CSK4 or lipopolysaccharide (LPS), TLR2/4 ligands respectively, modulate human megakaryocyte development and platelet production. METHODS: CD34+ cells from human umbilical cord were stimulated with LPS or Pam3CSK4 with or without thrombopoietin (TPO). RESULTS: CD34+ cells and megakaryocytes express TLR2 and TLR4 at both RNA and protein level; however, direct stimulation of CD34+ cells with LPS or Pam3CSK4 had no effect on cell growth. Interestingly, both TLR ligands markedly increased TPO-induced CD34+ cell proliferation, megakaryocyte number and maturity, proplatelet and platelet production when added at day 0. In contrast, this synergism was not observed when TLR agonists were added 7 days after TPO addition. Interleukin-6 (IL-6) release was observed upon CD34+ or megakaryocyte stimulation with LPS or Pam3CSK4 but not with TPO and this effect was potentiated in combination with TPO. The increased proliferation and IL-6 production induced by TPO + LPS or Pam3CSK4 were suppressed by TLR2/4 or IL-6 neutralizing antibodies, as well as by PI3K/AKT and nuclear factor-κB inhibitors. Additionally, increased proplatelet and platelet production were associated with enhanced nuclear translocation of nuclear factor-E2. Finally, the supernatants of CD34+ cells stimulated with TPO+LPS-induced CFU-M colonies. CONCLUSIONS: Our data suggest that the activation of TLR2 and TLR4 in CD34+ cells and megakaryocytes in the presence of TPO may contribute to warrant platelet provision during infection episodes by an autocrine IL-6 loop triggered by PI3K/NF-κB axes.
Asunto(s)
Antígenos CD34/metabolismo , Plaquetas/efectos de los fármacos , Lipopéptidos/farmacología , Lipopolisacáridos/farmacología , Megacariocitos/efectos de los fármacos , Trombopoyesis/efectos de los fármacos , Trombopoyetina/farmacología , Receptor Toll-Like 2/agonistas , Receptor Toll-Like 4/agonistas , Plaquetas/inmunología , Plaquetas/metabolismo , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Humanos , Interleucina-6/metabolismo , Megacariocitos/inmunología , Megacariocitos/metabolismo , FN-kappa B/metabolismo , Fosfatidilinositol 3-Quinasa/metabolismo , Transducción de Señal , Receptor Toll-Like 2/genética , Receptor Toll-Like 2/metabolismo , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/metabolismoRESUMEN
BACKGROUND: High platelet reactivity (HPR) during therapy with acetylsalicylic acid (ASA) is a poor prognostic factor in acute coronary syndromes (ACS). The prevalence of HPR during ACS is greater than that reported in stable diseases. However, it is unclear whether this prevalence of HPR is a transient phenomenon or a characteristic of this high-risk population. OBJECTIVE: The main objective is to compare the effects of ASA on platelet function in the initial and late phases of ACS in a single population. Secondary objectives are: correlation between the tests between themselves and the relationship between the tests and the variation of the inflammatory markers (C-reactive protein and interleukin-6). METHODS: Seventy patients with non-ST segment elevation (NSTE) ACS in use of 100-200 mg of ASA per day for at least 7 days were prospectively studied. Platelet function was assessed in the first 48 hours and subsequently after 3 months using four methods: VerifyNow™ (VFN), whole blood platelet aggregation (WBPA) with arachidonic acid (AA) and collagen as agonists, and platelet function analyzer (PFA). The level of statistical significance considered was < 0.05. RESULTS: According to the more specific methods (WBPA with AA and VFN), the incidence of HPR was significantly higher in the early phase than in the late phase: WBPA with AA: 31% versus 13%, p = 0.015; VFN: 32% versus 16%, p = 0.049. The other methods tested, which were less specific for ASA, did not show significant differences between phases. The correlation between the methods was weak or moderate (r ranging from 0.3 to 0.5, p < 0.05), and there were no significant associations between HPR and inflammatory markers. CONCLUSION: The prevalence of HPR during AAS therapy, assessed by specific methods for cyclooxygenase 1 (COX-1), is higher during the acute phase than in the late phase of NSTE ACS.
Asunto(s)
Síndrome Coronario Agudo/tratamiento farmacológico , Aspirina/uso terapéutico , Plaquetas/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Anciano , Aspirina/farmacología , Trastornos de las Plaquetas Sanguíneas/tratamiento farmacológico , Plaquetas/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio sin Elevación del ST/fisiopatología , Inhibidores de Agregación Plaquetaria/farmacología , Pruebas de Función Plaquetaria , Estudios Prospectivos , Factores de RiesgoRESUMEN
Myocardial infarction, commonly known as heart attack, evolves from the rupture of unstable atherosclerotic plaques to coronary thrombosis and myocardial ischemia-reperfusion injury. A body of evidence supports a close relationship between the alterations following an ischemia-reperfusion injury-induced oxidative stress and platelet activity. Through their critical role in thrombogenesis and inflammatory responses, platelets are fully (totally) implicated from atherothrombotic plaque formation to myocardial infarction onset and expansion. However, mere platelet aggregation prevention does not offer full protection, suggesting that other antiplatelet therapy mechanisms may also be involved. Thus, the present review discusses the integrative role of platelets, oxidative stress, and antiplatelet therapy in triggering myocardial infarction pathophysiology.