RESUMO
BACKGROUND: Platelet dysfunctions are shared by cardiovascular diseases and a wide range of inflammatory diseases. AIMS: To determine the ability of a new whole tomato-based food supplement (WTBFS) containing carotenoid and olive polyphenols to inhibit platelet aggregation. METHODS: Aggregation was evaluated in platelet-rich plasma using microtiter plates and a plate reader. RESULTS: Platelets treated with WTBFS showed a >70% reduction of 5 µM adenosine diphosphate (ADP)-induced platelet aggregation; at 10 µM of ADP, the inhibitory effect of WTBFS was reduced of about 50%. Similarly, 78% and 48% reduction were obtained using 5 µg/mL and 10 µg /mL of collagen as an agonist. CONCLUSION: Since the compounds in WTBFS share the ability to inhibit STAT3, the inhibition of its signaling pathway may represent the mechanism underlying the antiplatelet activities. The activity of a lipophilic solution prepared from WTBS was in vitro tested on the platelet aggregation in response to ADP agonists and Collagen.
Assuntos
Olea , Solanum lycopersicum , Humanos , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/fisiologia , Colágeno/farmacologia , Suplementos Nutricionais , Nutrientes , Difosfato de Adenosina/farmacologiaRESUMO
Cardiovascular events occur most frequently in the early morning. Similarly, the release of reticulated platelets (RP) by megakaryocytes has a peak in the late night and early morning. Which aspirin regimen most effectively inhibits platelets during these critical hours is unknown. Hence, the primary objective of this trial was to assess platelet function and RP levels at 8.00 AM, in stable cardiovascular (CVD) patients, during three different aspirin regimens. In this open-label randomized cross-over study subjects were allocated to three sequential aspirin regimens: once-daily (OD) 80 mg morning; OD-evening, and twice-daily (BID) 40 mg. Platelet function was measured at 8.00 AM & 8.00 PM by serum Thromboxane B2 (sTxB2) levels, the Platelet Function Analyzer (PFA)-200® Closure Time (CT), Aspirin Reaction Units (ARU, VerifyNow®), and RP levels. In total, 22 patients were included. At 8.00 AM, sTxB2 levels were the lowest after OD-evening in comparison with OD-morning (p = <0.01), but not in comparison with BID. Furthermore, RP levels were similar at 8.00 AM, but statistically significantly reduced at 8.00 PM after OD-evening (p = .01) and BID (p = .02) in comparison with OD-morning. OD-evening aspirin intake results in higher levels of platelet inhibition during early morning hours and results in a reduction of RP levels in the evening. These findings may, if confirmed by larger studies, be relevant to large groups of patients taking aspirin to reduce cardiovascular risk.
Assuntos
Aspirina/uso terapêutico , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/tratamento farmacológico , Agregação Plaquetária/fisiologia , Contagem de Plaquetas/métodos , Idoso , Aspirina/farmacologia , Estudos Cross-Over , Feminino , Humanos , Masculino , Fatores de TempoRESUMO
Blood coagulation is central to myocardial ischemia and reperfusion (IR) injury. Studies on the light elicited circadian rhythm protein Period 2 (PER2) using whole body Per2-/- mice found deficient platelet function and reduced clotting which would be expected to protect from myocardial IR-injury. In contrast, intense light induction of PER2 protected from myocardial IR-injury while Per2 deficiency was detrimental. Based on these conflicting data, we sought to evaluate the role of platelet specific PER2 in coagulation and myocardial ischemia and reperfusion injury. We demonstrated that platelets from mice with tissue-specific deletion of Per2 in the megakaryocyte lineage (Per2loxP/loxP-PF4-CRE) significantly clot faster than platelets from control mice. We further found increases in infarct sizes or plasma troponin levels in Per2loxP/loxP-PF4-CRE mice when compared to controls. As intense light increases PER2 protein in human tissues, we also performed translational studies and tested the effects of intense light therapy on coagulation in healthy human subjects. Our human studies revealed that intense light therapy repressed procoagulant pathways in human plasma samples and significantly reduced the clot rate. Based on these results we conclude that intense light elicited PER2 has an inhibitory function on platelet aggregation in mice. Further, we suggest intense light as a novel therapy to prevent or treat clotting in a clinical setting.
Assuntos
Coagulação Sanguínea/fisiologia , Plaquetas/metabolismo , Isquemia Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Proteínas Circadianas Period/metabolismo , Fototerapia , Animais , Humanos , Luz , Masculino , Camundongos , Isquemia Miocárdica/sangue , Traumatismo por Reperfusão Miocárdica/sangue , Proteínas Circadianas Period/genética , Agregação Plaquetária/fisiologia , ProteômicaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Although Canna edulis Ker Gawl rhizome has been used in Traditional Vietnamese Medicine to prevent and treat heart diseases without thorough scientific evidence, limited intensive search for the bioactivities and useful substances has been done. AIM OF THE STUDY: This study aims to investigate the antiplatelet aggregation, anticoagulant and antioxidant activity of extracts from C. edulis rhizome, separate and purify its compounds from the most active fraction and evaluate the antiplatelet aggregation, anticoagulant and antioxidant activity of isolated compounds. MATERIALS AND METHODS: C. edulis rhizome was extracted with ethanol, then fractionated with n-hexane, ethyl acetate and water. The inhibitory effect on adenosine diphosphate- and collagen-induced human platelet aggregation was evaluated. Prothrombin time, activated partial thromboplastine time and thrombine time were measured to examine the anticoagulant activity. The free radical scavenging ability was assessed with DPPH and ABTS assays. The fraction that showed the most active was used to separate and purify compounds. The structures of compounds were elucidated by NMR and MS spectroscopic methods. Isolated compounds were also tested for antiplatelet, anticoagulant and antioxidant activity. RESULTS: The ethyl acetate fraction showed the most potent antiplatelet aggregation, anticoagulant and antioxidant activity. Subsequent fractionation of this active fraction resulted in the isolation of seven known compounds: 5-hydroxy-6-methyl-2H-pyran-2-one (1), epimedokoreanone A (2), nepetoidin B (3), ferulic acid (4), caffeic acid (5), hydroxytyrosol (6), and 1H-indole-3-carboxaldehyde (7). Previous studies reported the antiplatelet, anticoagulant and antioxidant activity of ferulic acid (4), caffeic acid (5) and hydroxytyrosol (6) and the antioxidant activity of nepetoidin B (3). This study demonstrated that both epimedokoreanone A (2) and nepetoidine B (3) also exhibited good antiplatelet effect and epimedokoreanone A (2) also had effective anticoagulant and antioxidant activity, while 5-hydroxy-6-methyl-2H-pyran-2-one (1) showed weaker antiplatelet and antioxidant activity but no anticoagulant effect. CONCLUSIONS: This is the first experimental study to demonstrate the potent dose-dependent antiplatelet aggregation, anticoagulant and antioxidant activity of C. edulis rhizome and its pure compounds, supporting the traditional use of this plant for the treatment of heart diseases. The C. edulis rhizome is a potential source of bioactive compounds or functional food for treatment and/or prevention of heart- and oxidative stress-related diseases and its bioactive compounds are good candidates for drug development of anti-thrombosis and antioxidant agents.
Assuntos
Anticoagulantes/farmacologia , Antioxidantes/farmacologia , Extratos Vegetais/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Rizoma , Adolescente , Adulto , Anticoagulantes/isolamento & purificação , Antioxidantes/isolamento & purificação , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Agregação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/isolamento & purificação , Vietnã/etnologia , Adulto JovemRESUMO
Platelets play an important role in the development of endometriosis. Scutellarin is a flavonoid isolated from a medicinal herb traditionally used as a potent antiplatelet agent. In this study, we sought to evaluate its potential therapeutic effect, if any, in mice with induced endometriosis. Endometriosis was induced in 27 female Balb/c mice by intraperitoneal injection of uterine fragments. Two weeks after the induction, the 27 mice were randomly divided in equal sizes into 3 groups: untreated, which received only vehicle, and low-dose and high-dose groups, which received low- and high dose of scutellarin treatment. Hotplate test was administrated to all mice before endometriosis induction, and before and after the scutellarin treatment. Two weeks after the treatment, a blood sample was drawn before sacrifice and all lesions were harvested. The peripheral platelet activation rate and total lesion weight were assessed, and immunohistochemistry and histochemistry analyses were performed to evaluate the extent of proliferation, angiogenesis, fibroblast-to-myofibroblast transdifferentiation (FMT), and fibrosis in lesions. Compared with untreated mice, mice in both low-dose and high-dose groups had significantly reduced lesion weight and improved hyperalgesia. Scutellarin also reduced the peripheral-activated platelets rate and resulted in significantly reduced platelet aggregation, cellular proliferation, angiogenesis, the extent of FMT, and the extent of fibrosis in lesions. Thus, we conclude that scutellarin is efficacious in treating endometriosis in vivo by suppressing platelet aggregation, inhibiting proliferation, angiogenesis, and fibrogenesis, resulting in reduced lesion size and improved pain behavior. As such, scutellarin may be a potentially promising therapeutics for the treatment of endometriosis.
Assuntos
Apigenina/uso terapêutico , Endometriose/tratamento farmacológico , Glucuronatos/uso terapêutico , Medição da Dor/efeitos dos fármacos , Medição da Dor/métodos , Agregação Plaquetária/efeitos dos fármacos , Animais , Apigenina/farmacologia , Endometriose/metabolismo , Endometriose/patologia , Feminino , Glucuronatos/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Agregação Plaquetária/fisiologia , Distribuição AleatóriaRESUMO
Shortly after the discovery that linoleic acid was an essential fatty acid in 1930, α-linolenic acid also was reported to prevent the fatty acid deficiency syndrome in animals. However, several prominent laboratories could not confirm the findings with α-linolenic acid, and as a result there was a loss of interest in omega-3 fatty acids in lipid research. Even the findings that a prostaglandin can be synthesized from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is necessary for optimum retinal function generated only limited interest in omega-3 fatty acids. The breakthrough came in the 1970s when Dyerberg and Bang reported that the low incidence of atherosclerotic coronary disease in Greenland Eskimos was due to the high marine lipid content of their diet. They subsequently found that EPA, which was increased in Eskimo plasma, inhibited platelet aggregation, and they concluded that the low incidence of coronary artery disease was due to the anti-thrombotic effect of EPA. This stimulated widespread interest and research in EPA and DHA, leading to the present view that, like their omega-6 counterparts, omega-3 fatty acids have important physiological functions and are essential fatty acids.
Assuntos
Pesquisa Biomédica , Ácidos Graxos Ômega-3/farmacologia , Ácidos Graxos Ômega-3/fisiologia , Fibrinolíticos/farmacologia , Animais , Ácido Araquidônico/fisiologia , Doença da Artéria Coronariana/sangue , Trombose Coronária/sangue , Dieta , Humanos , Inuíte , Ácido Linoleico/fisiologia , Agregação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/fisiologia , RatosRESUMO
Platelet hyperactivity is the hallmark of thrombosis and hemostasis disorders including atherosclerosis, diabetes, stroke, arthritis, and cancer causing significant mortality and morbidity. Therefore, regulating platelet hyperactivity is an ever growing interest. Very recently, basal autophagic process has been demonstrated to be essential for normal functioning of platelets. However, autophagy can be elevated above basal level under conditions like starvation, and how platelets respond in these settings remains to be elucidative. Therefore, in this study we demonstrate a substantial autophagy induction (above basal level) by starvation, which decreases platelet aggregation responses to various agonists. The decreased aggregation in starved platelets was restored in combination with autophagy inhibitors (3-methyladenine and NH4Cl) and acetate supplementation. Starved platelets also showed decreased calcium mobilization, granule release, and adhesive properties. Furthermore, ex vivo platelets obtained from starved rats showed increased autophagy markers and decreased aggregation responses to various agonists. Our results distinctly explain that enhanced autophagy and cellular energy depletion are the cause for decreased platelet activation and aggregation. The study emphasizes the cardinal role of starvation and autophagy in the management of diseases and disorders associated with platelet hyperactivity.
Assuntos
Plaquetas/metabolismo , Agregação Plaquetária/fisiologia , Animais , Autofagia , Humanos , Ratos WistarRESUMO
BACKGROUND: The authors present evidence of the significance and role of the disturbances in platelet hemostasis in pathogenesis of co-morbid cardiac pathology and the absence of the unambiguous opinion as regards the expediency of the application of hyperbaric oxygenation (HBO) for their correction which implies the necessity of searching for new pathogenetically substantiated approaches to the treatment of the patients presenting with this condition. AIM: The objective of the present study was to evaluate the influence of hyperbaric oxygenation on the elastic properties of platelet membrane during spontaneous platelet aggregation in the patients presenting with cardiac co-morbidity. MATERIAL AND METHODS: Thrombocyte hemostasis was investigated in 24 patients at the age of 52.9±11.5 years (67% of men, 33% of women) presenting with functional class II angina of effort concomitant with arterial hypertension (AH). All the patients were given, in addition to the conventional treatment of the main diseases, the courses of daily (No. 5) 30-minute sessions of hyperbaric oxygenation in the 1,2ATA regime in the BLKS 301M and 303MK barochambers (Russia). Before and after HBO, spontaneous aggregation of thrombocytes (light agglomeration method) was determined with the use of a two-channel Biol LA-230-2 laser analyzer (Russia). The elastic properties of the platelet cell membrane were elucidated by atomic-force microscopy in the contact mode using the cantilever type PNP-DB on the Solver P47-PRO scanning probe microscope (Nt-MDT, Russia). RESULTS: The co-morbid cardiac pathology was accompanied by hyperaggregation and hypoaggregation of the platelets (33.3% and 25% respectively). The high levels of spontaneous aggregation in men (1.46±0.47) and the dependence of platelet plate stiffness on the aggregation state were documented. HBO sessions were accompanied by a reduction of spontaneous platelet aggregation in men (0.84±0.19) and a two-fold decrease in the modulus of elasticity in comparison with its initial value in the patients with platelet hyperaggregation (0.42±0.16, p<0.05). CONCLUSION: The membrane-modifying effect of HBO on the platelets is characterized by an increase in the elasticity of their membranes concurrent with a reduction of spontaneous aggregation of platelets, predominantly in men.
Assuntos
Doenças Cardiovasculares/terapia , Oxigenoterapia Hiperbárica , Agregação Plaquetária/fisiologia , Adulto , Doenças Cardiovasculares/epidemiologia , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Federação RussaRESUMO
CONTEXT: The rising problem of atherosclerosis and ischemic heart disease emphasizes the need to look for new antithrombotic components with effective modes of action. Corydalis yanhusuo (Y.H. Chou & Chun C. Hsu) W.T. Wang ex Z.Y. Su & C.Y. Wu (Papaveraceae) (Rhizoma Corydalis) has been used in the traditional medicines for the treatment of cardiovascular disease. OBJECTIVE: The antiplatelet aggregation compounds in Rhizoma Corydalis were screened to validate its traditional medicinal use. MATERIAL AND METHODS: Total alkaloid extract (TAE) of Rhizoma Corydalis was obtained by refluxing 100 g Rhizoma Corydalis powder with 600 mL 70% ethanol, and purified by acidification (20% HCl) and alkalization (5 M NaOH) process. Potential antiplatelet aggregation compounds in TAE were screened by a method involving platelet bio-specific extraction and HPLC-DAD/LC-MS analysis. Further in vitro antiplatelet aggregation activity confirmation of TAE and seven main alkaloids were achieved by turbidimetry method within 3 h after blood collection from rabbit carotid artery, and all the test drugs were at the concentration range of 25-350 µg/mL. Finally, HPLC-DAD was employed for the quantitative determination of seven main components in TAE. RESULTS: Five alkaloids, identified as glaucine, dehydrocorydaline, canadine, tetrahydrocoptisine and corydaline, can be specifically extracted with platelets. The results indicated that all these five alkaloids can inhibit thrombin-induced platelet aggregation in a low dose (IC50 of glaucine, dehydrocorydaline, canadine, tetrahydrocoptisine and corydaline were 49.057, 34.914, 33.547, 84.261 and 54.164 µg/mL, respectively) as compared to TAE (IC50 = 175.426 µg/mL) and aspirin (IC50 = 300.340 µg/mL), while the unbound compounds (palmatine and tetrahydropalmatine) had a very weak antiplatelet effect (IC50 > 200 µg/mL). DISCUSSION AND CONCLUSION: This study is the first reported work for antiplatelet components screening in Rhizoma Corydalis. Seven compounds were detected and identified by HPLC-DAD/LC-MS, of which five platelet-targeted compounds were discovered.
Assuntos
Alcaloides/análise , Corydalis , Extratos Vegetais/análise , Inibidores da Agregação Plaquetária/análise , Agregação Plaquetária/efeitos dos fármacos , Rizoma , Alcaloides/farmacologia , Animais , Extratos Vegetais/farmacologia , Agregação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/farmacologia , CoelhosRESUMO
Diabetes mellitus (DM) is a disease condition characterised by hyperglycemia; free radical and abnormalhaematological indices. Vitamin C can reduce free radical generation and ameliorate adverse conditions of diabetes mellitus.The aim of the present study is to investigate the effect of vitamin C on platelet aggregation and electrolyte levels in Type 1DM. Male Wistar rats were divided into four groups namely control, DM, DM +Vitamin C and Vitamin C groups. Rats weremade diabetic with a single dose of streptozotocin (65 mg/kg) intraperitoneally. Vitamin C was administered orally todiabetic and normal rats at 200 mg/kg body weight for 28 days. Blood samples were analyzed for hematological parameters,platelet aggregation, and serum electrolyte levels. Blood glucose in DM+ Vitamin C group (9.9 ± 1.8 mmol/L) wassignificantly reduced (p<0.01) compared to DM group (32.2 ± 2.1 mmol/L) and significantly higher (p<0.05) than control(4.4 ± 0.8 mmol/L). Haemoglobin (Hb) concentration in DM group (12 ± 0.1 g/dL) was significantly reduced (p<0.01) whencompared with control groups (14 ± 0.24 g/dL) and significantly increased (p<0.05) in the DM+vitamin C group (13.5 ± 0.5g/dL) compared with the diabetic group. The mean corpuscular volume values in DM (68.66 ± 0.5 fL) and DM+vitamin Cgroups (68.11 ± 0.4 fL) were significantly higher (p<0.01) than the control (59.49 ± 0.5fL). Platelet count in DM group (523± 8.5 x109/L) was significantly raised (p<0.01) when compared to control (356 ± 6.2 x109/L) and significantly reduced(p<0.01) in DM+ vitamin C-treated group (385 ± 7.8 x109/L) compared with DM group. Platelet aggregation and serumsodium/potassium ratios was significantly reduced (p<0.01) in DM+vitamin C compared with DM group. These resultssuggest that oral vitamin C administration increases haemoglobin, reduced plasma glucose level, platelet count, serumsodium/potassium ion ratio and inhibits platelet aggregation in streptozotocin-induced DM in rats.
Assuntos
Ácido Ascórbico/administração & dosagem , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Suplementos Nutricionais , Eletrólitos/sangue , Agregação Plaquetária/efeitos dos fármacos , Administração Oral , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Masculino , Agregação Plaquetária/fisiologia , Ratos , Ratos Wistar , Estreptozocina , Resultado do TratamentoRESUMO
AIM: To study the impact of low-intensity laser therapy (LILT) on typical pathological processes of impairments in platelet aggregation and microcirculation (MC) in patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: A photo optical aggregatometric method was used to investigate platelet aggregation function in patients with COPD and MC was estimated by laser Doppler flowmetry over time. RESULTS: There were muitidirectional changes in platelet aggregation function with a predominance of hyperaggregation, as well as a significant improvement in aggregation indicators during LILT; the latter was shown to have a correcting impact on MC disorders in patients with COPD in the presence of the spastic and stagnant-stasic types of MC, which were prevalent in the majority of patients. CONCLUSION: Laser therapy used in the combination treatment of patients with COPD promotes correction of the typical pathological processes.
Assuntos
Terapia com Luz de Baixa Intensidade/métodos , Microcirculação/fisiologia , Avaliação de Resultados em Cuidados de Saúde , Agregação Plaquetária/fisiologia , Doença Pulmonar Obstrutiva Crônica/terapia , Idoso , Terapia Combinada , Feminino , Humanos , Fluxometria por Laser-Doppler , Masculino , Pessoa de Meia-IdadeRESUMO
Bioactive compounds present in foods could have beneficial effects on human health. In this study, we report the capacity of peptides released from oat, highland barley, and buckwheat proteins after enzymatic digestion to inhibit platelet aggregation in vitro. All hydrolysates showed high antiplatelet activity, with IC50 values of 0.282mg/ml (oat flour gastrointestinal hydrolysate, 6h) to 2.496mg/ml (highland barley glutelin tryptic hydrolysate, 14h) in a dose-dependent manner. Thirty-eight peptides with more than seven residues were identified in the tryptic hydrolysates of oat globulin. Results of computational modeling revealed that nine peptides, including ALPIDVLANAYR, EFLLAGNNKR, GEEFGAFTPK, QLAQIPR, LQAFEPLR, ALPVDVLANAYR, GEEFDAFTPK, QKEFLLAGNNK, and TNPNSMVSHIAGK bound the cyclooxygenase-1 active centers with low binding energy (-6.5 to -7.5kcal/mol). This is the first report to identify antiplatelet peptides from grain hydrolysates and the binding modes at the molecular level, leading to their possible use as functional food ingredients to prevent thrombosis.
Assuntos
Avena/química , Cromatografia Líquida/métodos , Fagopyrum/química , Hordeum/química , Espectrometria de Massas/métodos , Peptídeos/fisiologia , Agregação Plaquetária/fisiologia , HumanosRESUMO
An effective and safe anti-platelet drug is central to the management of patients with acute coronary syndrome (ACS). Glycoprotein VI (GPVI) is currently regarded as a potential target for novel anti-platelet agents due to its collagen-binding potential. Development of anti-thrombotics is associated with testing in animals. We have previously successfully evaluated anti-platelet drugs in the Cape Chacma baboon (Papio ursinus). However, various anti-GPVI agents did not have an effect on baboons when evaluated in our arterial thrombosis model. To evaluate the suitability of baboons for GPVI studies, we performed collagen-induced platelet aggregation, GPVI quantification and DNA sequencing. Baboon platelets needed double the amount of collagen compared to human platelets to illicit proper aggregation. GPVI quantification was unsuccessful due to non-binding of monoclonal antibodies. Sequencing of the GPVI gene revealed 36 SNPs leading to 14 amino acid changes, as well as a 9 bp deletion causing a 3 amino acid deletion. Several of the amino acid changes were within the ligand binding region of GPVI, causing limited binding of humanized anti-GPVI antibodies to the baboon platelets. Therefore, the baboon was deemed not suitable to evaluate human targeted anti-GPVI agents.
Assuntos
Anticorpos Monoclonais/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Glicoproteínas da Membrana de Plaquetas/antagonistas & inibidores , Substituição de Aminoácidos , Animais , Anticorpos Monoclonais/uso terapêutico , Sequência de Bases , Colágeno/metabolismo , Colágeno/farmacologia , Avaliação Pré-Clínica de Medicamentos , Humanos , Modelos Animais , Dados de Sequência Molecular , Papio ursinus , Agregação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/uso terapêutico , Glicoproteínas da Membrana de Plaquetas/química , Glicoproteínas da Membrana de Plaquetas/genética , Glicoproteínas da Membrana de Plaquetas/metabolismo , Polimorfismo de Nucleotídeo Único , Alinhamento de SequênciaRESUMO
OBJECTIVE: Platelets are key cells in atherosclerosis and acute cardiovascular events. Platelet hyperreactivity and increased platelet-monocyte aggregation (PMA) are found in HIV-infected patients and may contribute to the excess cardiovascular risk. The integrase inhibitor raltegravir (RAL) has been associated with better residual viral suppression and reduction in inflammatory and coagulation biomarkers. The aim of our study was to investigate whether RAL-treated patients have reduced platelet reactivity and PMA. DESIGN AND METHODS: We performed a cross-sectional study involving 80 virologically suppressed adult HIV1-infected patients on a RAL-based (n = 25), nonnucleoside reverse transcriptase inhibitor (NNRTI)-based (n = 30) or a protease inhibitor based (n = 25) regimen and 30 healthy controls. Platelet reactivity was determined by measuring platelet P-selectin expression and the binding of fibrinogen to platelets to stimulation with two concentrations of ADP. PMA was determined by measuring the expression of the platelet marker CD42b on CD14 positive cells. RESULTS: HIV-infected individuals had higher platelet reactivity and PMA than controls. RAL-treated individuals showed significantly lower P-selectin expression to stimulation with low (P = 0.026 vs. NNRTI and P = 0.005 vs. protease inhibitor group) and high-dose ADP (P = 0.009 vs. NNRTI and P = 0.003 vs. protease inhibitor group). A similar trend for was found for fibrinogen binding, although only the difference in P-selectin expression between RAL and protease inhibitor treated patients reached statistical significance (P = 0.038). PMA was also lower in the RAL group than in the NNRTI (P = 0.037) and protease inhibitor (P = 0.034) groups. CONCLUSION: Use of a RAL-based regimen was associated with a reduction in persistent HIV-induced platelet hyperreactivity and PMA compared with NNRTI and protease inhibitor based regimen.
Assuntos
Plaquetas/efeitos dos fármacos , Doença da Artéria Coronariana/tratamento farmacológico , Infecções por HIV/tratamento farmacológico , Monócitos/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Pirrolidinonas/uso terapêutico , Inibidores da Transcriptase Reversa/uso terapêutico , Plaquetas/fisiologia , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/fisiopatologia , Estudos Transversais , Infecções por HIV/sangue , Infecções por HIV/fisiopatologia , Humanos , Monócitos/fisiologia , Selectina-P/sangue , Agregação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/uso terapêutico , Raltegravir Potássico , Fatores de Risco , Resultado do TratamentoRESUMO
OBJECTIVE: To evaluate patients' hemostasis after cardiac surgery using thromboelastometric and impedance aggregometry. MATERIALS AND METHODS: 66 patients were examined intraoperatively. Comparison group included 45 blood donors. Hemostasis was tested for thromboelastometricRotem Gamma with the assessment of external (exTem) and internal (inTem) pathways of coagulation tests performed detection of heparin (hepTem) and cytochalasin-D-inactivation of platelets (fibTem) to assess the level of fibrinogen. Collagen-induced platelet aggregation was determined in an aggregometer CHRONO-LOG (USA). RESULTS: Significant deviations of the parameters of hemostasis were detected in 52 of the 66 studied patients. In group-1 (23 patients) revealed a residual effect of heparin. The effect manifested prolongation CT (clotting time) inTem to an average of 241 +/- 15 s, compared with CT hepTem--181 +/- 7. Patients in this group were in need of additional administration of protamine sulfate. Postoperative bleeding and resternotomia were observed in 3 patients of group-1. In group-2 (25 patients) CT inTem was 216 +/- 21 with significantly fewer CT hepTem (272 +/- 26). The data indicated excess of protamine sulfate. Platelets aggregation decreased compared to the norm. According to the obtained results, the addition of protamine sulfate is not required, however, in 7 cases the protamine sulfate was administered in a dose of 8.9 +/- 0.8 mg in 6 cases resternotomiya required. In the third group (n = 6) bleeding was observed in 4 patients. The difference in CT-hepCT was significant. Significant variations were revealed in the tests of the activity of the extrinsic pathway of coagulation and cytochalasin-D-induced inactivation of platelets: exMCF- 42 +/- 2 mm (normal 57 +/- 15 mm), fibMCF 5.0 +/- 0.3 mm (norm 12.8 +/- 4.3 mm). The concentration of platelets and their aggregation activity was sharply reduced. Disorders of hemostasis in the third group, designated as dilution coagulopathy. CONCLUSION: Turning thromboelastometric and impedance aggregometry in the study of the coagulation profile of patients undergoing cardiac surgery in postperfusion period brings valuable information and allows a differentiated treatment of hemostasis disorders.
Assuntos
Transtornos da Coagulação Sanguínea/prevenção & controle , Coagulação Sanguínea/fisiologia , Procedimentos Cirúrgicos Cardíacos , Hemostasia/fisiologia , Monitorização Intraoperatória/métodos , Anticoagulantes/administração & dosagem , Anticoagulantes/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Transtornos da Coagulação Sanguínea/diagnóstico , Perda Sanguínea Cirúrgica/prevenção & controle , Transfusão de Sangue Autóloga/métodos , Estudos de Casos e Controles , Hemostasia/efeitos dos fármacos , Heparina/administração & dosagem , Heparina/uso terapêutico , Humanos , Recuperação de Sangue Operatório/métodos , Agregação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/fisiologia , Tromboelastografia/métodos , Tempo de Coagulação do Sangue Total/métodosRESUMO
Currently, there are several animal models of diabetes mellitus and hypertension, but relatively little is known about blood platelet function in these models. The aim of this work was to characterise and compare platelet reactivity and activation in db/db mice (mouse model of diabetes) and mice receiving L-NAME (model of chronic inhibition of NO synthesis), using various platelet function assays. We found higher platelet activation (circulating resting platelets) in db/db mice than in db/+heterozygotes, as evidenced by elevated expressions of CD62P and CD40L and a lower expression of CD42b. The expression of COX-1 was significantly increased, and the phosphorylation of vasodilator stimulated phosphoprotein (VASP) Ser(157) significantly reduced in platelets from db/db mice. Similarly, we observed platelet hyperreactivity in db/db mice following the in vitro responses to 20µg/ml collagen (reflected by increased expressions of CD62P and CD40L, and reduced CD42b), 20µM ADP (reduced CD42b) and lower concentrations of thrombin (0.025 U/ml) (increased CD62P, JON/A, bound vWF, and bound fibrinogen). Otherwise, platelet hyporeactivity was revealed for higher thrombin (0.25 U/ml) (reduced CD62P and bound vWF), while hyperreactivity occurred for CD40L and bound Fg in db/db mice compared to non-diabetic control, db/+. Plasma levels of sCD40L, but not of sCD62P, were increased in db/db mice; also plasma TXB2 concentrations were over 3.5-fold higher in this group than in the heterozygous db/+mice (P<0.01). In contrast, in the mice administered with L-NAME, no statistical differences in expressions of platelet activation markers were found between mice supplemented with L-NAME and controls. Likewise, the TXB2 level did not differ between L-NAME mice and controls, but L-NAME mice had significantly higher plasma levels of sCD62P and sCD40L than controls. In conclusion, these two studied models differ in the overall picture of blood platelet activation and reactivity, as they demonstrated opposite time sequence patterns of platelet activation in circulating blood. More generally, our study provides another argument for the opinion that multiparametric analysis of platelet function offers a much better tool for investigation and minimizes the likelihood of artefacts.
Assuntos
Plaquetas/fisiologia , Diabetes Mellitus Experimental/sangue , Óxido Nítrico Sintase/antagonistas & inibidores , Ativação Plaquetária/fisiologia , Agregação Plaquetária/fisiologia , Animais , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Ligante de CD40/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/enzimologia , Hipertensão/sangue , Hipertensão/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NG-Nitroarginina Metil Éster/farmacologia , Selectina-P/sangue , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Distribuição Aleatória , Tromboxano B2/sangueRESUMO
Platelet aggregation and thrombus formation at the site of injury is a dynamic process that involves the continuous addition of new platelets as well as thrombus rupture. In the early stages of hemostasis (within minutes after vessel injury) this process can be visualized by transfusing fluorescently labeled human platelets and observing their deposition and detachment. These two counterbalancing events help the developing thrombus reach a steady-state morphology, where it is large enough to cover the injured vessel surface but not too large to form a severe thrombotic occlusion. In this study, the spatial and temporal aspects of early stage thrombus dynamics which result from laser-induced injury on arterioles of cremaster muscle in the humanized mouse were visualized using fluorescent microscopy. It was found that rolling platelets show preference for the upstream region while tethering/detaching platelets were primarily found downstream. It was also determined that the platelet deposition rate is relatively steady, whereas the effective thrombus coverage area does not increase at a constant rate. By introducing a new method to graphically represent the real time in vivo physiological shear stress environment, we conclude that the thrombus continuously changes shape by regional growth and decay, and neither dominates in the high shear stress region.
Assuntos
Plaquetas/fisiologia , Agregação Plaquetária/fisiologia , Trombose/patologia , Animais , Modelos Animais de Doenças , Humanos , Terapia com Luz de Baixa Intensidade , CamundongosRESUMO
BACKGROUND: Transfusion of platelet concentrate is often used to treat bleeding in patients on platelet inhibitors, but little is known about its efficacy between different inhibitors. We assessed the effect of ex vivo platelet supplementation on platelet aggregability in blood samples from patients treated with acetylsalicylic acid (ASA), clopidogrel, or ticagrelor. METHODS: Platelet aggregability was investigated with multiple electrode aggregometry with adenosine diphosphate (ADP), arachidonic acid (to assess ASA-dependent aggregability), and thrombin receptor activating peptide-6 (TRAP) as activators in whole-blood samples from patients treated with ASA (n=10), ASA+clopidogrel (n=15), or ASA+ticagrelor (n=15), and from healthy controls (n=10). Aggregability was measured before and after supplementation of AB0-compatible fresh apheresis platelets (+46, +92, and +138×10(9) litre(-1)). RESULTS: Both ASA-dependent and ADP-dependent aggregability improved in a dose-dependent fashion after platelet supplementation. ASA-dependent aggregability was completely restored in all patient groups, but there was only a small improvement in ADP-dependent aggregability in patients on dual antiplatelet therapy. There was less effect of platelet supplementation on ADP- and ASA-dependent aggregability in ticagrelor-treated patients than in clopidogrel-treated patients [3.9 (95% confidence interval 1.6-6.3) vs 9.0 (5.2-12.8) AU×min (P=0.021) and 48 (36-59) vs 69 (60-78) AU×min (P=0.004), respectively, at the highest platelet dose]. CONCLUSIONS: Platelet supplementation improved platelet aggregability independently of antiplatelet therapy. The effect on ADP-dependent platelet inhibition was limited however. Reduced effect of platelet transfusion is more likely within 2 h of drug intake in patients treated with ASA+ticagrelor compared with ASA+clopidogrel.
Assuntos
Adenosina/análogos & derivados , Aspirina/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/fisiologia , Transfusão de Plaquetas , Ticlopidina/análogos & derivados , Adenosina/farmacologia , Difosfato de Adenosina , Idoso , Ácido Araquidônico/farmacologia , Clopidogrel , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/farmacologia , Ticagrelor , Ticlopidina/farmacologiaRESUMO
The objective of this study was to describe the results of thromboelastography platelet mapping (TEG-PM) carried out using 2 techniques in 20 healthy dogs. Maximum amplitudes (MA) generated by thrombin (MAthrombin), fibrin (MAfibrin), adenosine diphosphate (ADP) receptor activity (MAADP), and thromboxane A2 (TxA2) receptor activity (stimulated by arachidonic acid, MAAA) were recorded. Thromboelastography platelet mapping was carried out according to the manufacturer's guidelines (2-analyzer technique) and using a variation of this method employing only 1 analyzer (1-analyzer technique) on 2 separate blood samples obtained from each dog. Mean [± standard deviation (SD)] MA values for the 1-analyzer/2-analyzer techniques were: MAthrombin = 51.9 mm (± 7.1)/52.5 mm (± 8.0); MAfibrin = 20.7 mm (± 21.8)/23.0 mm (± 26.1); MAADP = 44.5 mm (± 15.6)/45.6 mm (± 17.0); and MAAA = 45.7 mm (± 11.6)/45.0 mm (± 15.4). Mean (± SD) percentage aggregation due to ADP receptor activity was 70.4% (± 32.8)/67.6% (± 33.7). Mean percentage aggregation due to TxA2 receptor activity was 77.3% (± 31.6)/78.1% (± 50.2). Results of TEG-PM were not significantly different for the 1-analyzer and 2-analyzer methods. High correlation was found between the 2 methods for MAfibrin [concordance correlation coefficient (r) = 0.930]; moderate correlation was found for MAthrombin (r = 0.70) and MAADP (r = 0.57); correlation between the 2 methods for MAAA was lower (r = 0.32). Thromboelastography platelet mapping (TEG-PM) should be further investigated to determine if it is a suitable method for measuring platelet dysfunction in dogs with thrombopathy.
Cette étude visait à décrire les résultats de la cartographie de la thromboélastographie des plaquettes (TEG-PM) effectuée à l'aide de deux techniques chez 20 chiens en santé. L'amplitude maximale (MA) générée par la thrombine (MAthrombine), la fibrine (MAfibrine), l'activité du récepteur de l'adénosine diphosphate (ADP) (MAADP), l'activité du récepteur de la thromboxane A2 (TxA2) (stimulée par l'acide arachidonique, MAAA) ont été mesurées. La TEG-PM a été effectuée selon les recommandations du manufacturier (technique à 2 analyseurs) ainsi qu'une variation de cette méthode en utilisant seulement un analyseur (technique à 1 analyseur) sur deux échantillons sanguins séparés obtenus de chaque chien. Les valeurs moyennes [± écart-type (SD)] de MA pour les techniques à 1 analyseur/2 analyseurs étaient: MAthrombine = 51,9 mm (± 7,1)/52,5 mm (± 8,0); MAfibrine = 20,7 mm (± 21,8)/23,0 mm (± 26,1); MAADP = 44,5 mm (± 15,6)/45,6 mm (± 17,0); et MAAA = 45,7 mm (± 11,6)/45,0 mm (± 15,4). La moyenne (± SD) du pourcentage d'agrégation due à l'activité du récepteur ADP était de 70,4 % (± 32,8)/67,6 % (± 33,7). La moyenne du pourcentage d'agrégation due à l'activité du récepteur TxA2 était de 77,3 % (± 31,6)/78,1 % (± 50,2). Il n'y avait pas de différence significative dans les résultats de TEG-PM entre les méthodes à 1 analyseur ou à 2 analyseurs. Une corrélation élevée a été trouvée entre les deux méthodes pour la MAfibrine [coefficient de concordance de corrélation (r) = 0,930]; une corrélation modérée a été trouvée pour MAthrombine (r = 0,70) et MAADP (r = 0,57); la corrélation entre les deux méthodes pour MAAA était plus faible (r = 0,32). Des études supplémentaires devraient être effectuées pour déterminer si la TEG-PM est une méthode qui convient pour mesurer le dysfonctionnement des plaquettes chez les chiens avec thrombopathie.(Traduit par Docteur Serge Messier).
Assuntos
Plaquetas/fisiologia , Cães/fisiologia , Agregação Plaquetária/fisiologia , Tromboelastografia/veterinária , Difosfato de Adenosina/farmacologia , Animais , Feminino , Fibrina/farmacologia , Masculino , Estatísticas não Paramétricas , Tromboelastografia/métodos , Trombina/farmacologia , Tromboxano A2/farmacologiaRESUMO
Nitric oxide (NO) appears to play an important role in the regulation of thrombosis and hemostasis by inhibiting platelet function. The discovery of NO generation by reduction of nitrite (NO2â») and nitrate (NO3â») in mammals has led to increased attention to these anions with respect to potential beneficial effects in cardiovascular diseases. We have previously shown that nitrite anions at 0.1 µM inhibit aggregation and activation of human platelet preparations in vitro in the presence of red blood cells and this effect was enhanced by deoxygenation, an effect likely due to NO generation. In the present study, we hypothesized that nitrite and nitrate derived from the diet could also alter platelet function upon their conversion to NO in vivo. To manipulate the levels of nitrite and nitrate in mouse blood, we used antibiotics, NOS inhibitors, low nitrite/nitrate (NOx) diets, endothelial NOS knock-out mice and also supplementation with high levels of nitrite or nitrate in the drinking water. We found that all of these perturbations affected nitrite and nitrate levels but that the lowest whole blood values were obtained by dietary restriction. Platelet aggregation and ATP release were measured in whole blood and the results show an inverse correlation between nitrite/nitrate levels and platelet activity in aggregation and ATP release. Furthermore, we demonstrated that nitrite-supplemented group has a prolonged bleeding time compared with control or low NOx diet group. These results show that diet restriction contributes greatly to blood nitrite and nitrate levels and that platelet reactivity can be significantly affected by these manipulations. Our study suggests that endogenous levels of nitrite and nitrate may be used as a biomarker for predicting platelet function and that dietary manipulation may affect thrombotic processes.