Study on Platelet Adhesion and Aggregation Induced by Gradient Shear Stress Using Microfluidic Chip Technology / 中国实验血液学杂志

OBJECTIVE@#To study the effect of gradient shear stress on platelet aggregation by microfluidic chip Technology.@*METHODS@#Microfluidic chip was used to simulate 80% fixed stenotic microchannel, and the hydrodynamic behavior of the stenotic microchannel model was analyzed by the finite element analysis module of sollidwork software. Microfluidic chip was used to analyze the adhesion and aggregation behavior of platelets in patients with different diseases, and flow cytometry was used to detect expression of the platelet activation marker CD62p. Aspirin, Tirofiban and protocatechuic acid were used to treat the blood, and the adhesion and aggregation of platelets were observed by fluorescence microscope.@*RESULTS@#The gradient fluid shear rate produced by the stenosis model of microfluidic chip could induce platelet aggregation, and the degree of platelet adhesion and aggregation increased with the increase of shear rate within a certain range of shear rate. The effect of platelet aggregation in patients with arterial thrombotic diseases were significantly higher than normal group (P<0.05), and the effect of platelet aggregation in patients with myelodysplastic disease was lower than normal group (P<0.05).@*CONCLUSION@#The microfluidic chip analysis technology can accurately analyze and evaluate the platelet adhesion and aggregation effects of various thrombotic diseases unde the environment of the shear rate, and is helpful for auxiliary diagnosis of clinical thrombotic diseases.

Exploring molecular mechanisms of anti-platelet adhesion of Chinese medicine for promoting blood circulation and removing blood stasis by activity screen and network analysis / 药学学报

Platelet adhesion is a key process in thrombosis. Anti-platelet adhesion effect of some Chinese medicines for promoting blood circulation and removing blood stasis (PBCRBS) has been reported, but their relative efficacies as a whole and specific targets remained unclear. This paper combined activity screening, drug compatibility analysis, pathway clustering, target prediction, and molecular docking to explore the mechanism of anti-platelet adhesion by PBCRBS Chinese medicine. Screening the activity of anti-platelet adhesion of 58 commercially available PBCRBS Chinese patent medicines showed that about 50.0% significantly inhibit ADP-induced platelet adhesion in vitro, and about 96.6% significantly inhibit thrombin-induced platelet adhesion in vitro. The animal experiment involved was approved by the Animal Ethics Committee of Tianjin International Biomedical Research Institute. Combined with the auxiliary platform for TCM (V2.0) inheritance showed that the compatibility of Danshen-Chuanxiong was used most frequently among the top 20 active proprietary Chinese patent medicines. IPA network analysis revealed that IL-1, APP and CCL2 might be the key targets for anti-platelet adhesion function of Danshen-Chuanxiong against atherosclerosis, neuroinflammation and chemokine signaling pathways as the main mechanisms. Molecular docking analysis confirmed the interaction between one of the active compounds shared by Danshen and Chuanxiong, i.e. chlorogenic acid, with its target CCL2. This study provides TCM theory guidance and experimental support for targeting platelet adhesion in anti-thrombosis therapy by Chinese medicine for promoting blood circulation and removing blood stasis.

A simple microfluidic technology for assaying platelet adhesion and aggregation under physiological flow / 军事医学

Objective To develop a simple microfluidic chip technology for analyzing platelet adhesion and aggregation under the condition of physiological flow .Methods The basic structure of the proposed microfluidic chip was a straight microchannel , where a sample pool and an outlet were located on each side respectively .The fluid dynamic behavior ,of the fluid in the microchannel was analyzed by theoretical calculation and finite element numerical analysis software ANSYS . The microchannel was first coated with type Ⅰ collagen protein.Then,blood flowed through the microchannel at 200 s-1 venous physiological shear rate and 1000 s-1 arterial physiological shear rate respectively .The behavior of the fluorescence labeled platelet adhesion and aggregation was recorded by fluorescence microscopy .Results Theoretical calculation and finite element numerical analysis showed that the microchannel with a width of 700 μm and a height of 70 μm ( aspect ration 10:1 ) had a uniform fluidic shear rate distribution .Compared with those at the 200 s-1 shear rate, the initial adhesion time, aggregation rate and the maximum surface cover rate of the platelet were significantly reduced at the 1000 s-1 shear rate ( P<0.05 ) .At the 1000 s-1 shear rate, tirofiban, an anticoagulant drug , significantly reduced the platelet aggregation in a concentration-dependent manner and the IC 50 was 23.8 nmol/L.Conclusion The technology developed in this paper can dynamically assay platelet adhesion and aggregation under the condition of physiological flow . The proposed microfluidic methods have the advantage of simple implementation and low sample cousumpation , and can be used for point-of-care detection of human platelet function , assay of the efficacy of anticoagulant drugs and for inspection of the thrombin behaviors of small animal models .

A simple microfluidic technology for assaying platelet adhesion and aggregation under physiological flow / 军事医学

Objective To develop a simple microfluidic chip technology for analyzing platelet adhesion and aggregation under the condition of physiological flow .Methods The basic structure of the proposed microfluidic chip was a straight microchannel , where a sample pool and an outlet were located on each side respectively .The fluid dynamic behavior ,of the fluid in the microchannel was analyzed by theoretical calculation and finite element numerical analysis software ANSYS . The microchannel was first coated with type Ⅰ collagen protein.Then,blood flowed through the microchannel at 200 s-1 venous physiological shear rate and 1000 s-1 arterial physiological shear rate respectively .The behavior of the fluorescence labeled platelet adhesion and aggregation was recorded by fluorescence microscopy .Results Theoretical calculation and finite element numerical analysis showed that the microchannel with a width of 700 μm and a height of 70 μm ( aspect ration 10:1 ) had a uniform fluidic shear rate distribution .Compared with those at the 200 s-1 shear rate, the initial adhesion time, aggregation rate and the maximum surface cover rate of the platelet were significantly reduced at the 1000 s-1 shear rate ( P<0.05 ) .At the 1000 s-1 shear rate, tirofiban, an anticoagulant drug , significantly reduced the platelet aggregation in a concentration-dependent manner and the IC 50 was 23.8 nmol/L.Conclusion The technology developed in this paper can dynamically assay platelet adhesion and aggregation under the condition of physiological flow . The proposed microfluidic methods have the advantage of simple implementation and low sample cousumpation , and can be used for point-of-care detection of human platelet function , assay of the efficacy of anticoagulant drugs and for inspection of the thrombin behaviors of small animal models .

Revacept: Collagen GP VI receptor inhibitor, a new & a formidable target for antiplatelet action.

Antiplatelet drugs play an important role in the prevention as well as treatment of cardiovascular diseases like coronary artery disease and stroke. Many of the currently available antiplatelet drugs face limitations due to safety and efficacy issues. A new antiplatelet drug, revacept i.e. a collagen receptor antagonist, has been shown to reduce platelet adhesion by blocking GP VI-dependent pathways without increasing the risk of bleeding complications and without affecting the general hemostasis.

El síndrome de las plaquetas pegajosas y su diagnóstico en el laboratorio / The sticky platelet syndrome and its diagnosis in the laboratory

El síndrome de las plaquetas pegajosas (SPP) es un trastorno plaquetario autosómico dominante considerado como una de las causas más frecuentes de eventos trombóticos, tanto arteriales como venosos. Este síndrome supone trastornos en la agregación de las plaquetas caracterizados por su incremento anormal. El mecanismo patogénico no se conoce; su existencia puede determinarse con las pruebas de agregación y adhesión plaquetarias. Tampoco se conoce su prevalencia, pero hay datos que sugieren que es frecuente. Algunos investigadores plantean que es responsable del 23 por ciento de las trombosis arteriales inexplicables y del 14 por ciento de las venosas, en las que no es posible identificar una causa. Se presenta una breve revisión acerca de la información disponible sobre el síndrome de las plaquetas pegajosas y su trascendencia en la salud. En Cuba existen pocos reportes de la evaluación clínica de pacientes con esta afección, por lo que resulta necesario realizar estudios más profundos para establecer la magnitud de la enfermedad

The sticky platelet syndrome (SPS) is an autosomal dominant platelet disorder considered as one of the most common causes of thrombotic events, both arterial and venous. This syndrome involves disturbances in platelet aggregation characterized by abnormal increase. The pathogenic mechanism is not known. Its existence can be determined by platelet aggregation and platelet adhesion tests. Its prevalence is also unknown, but evidence suggests that it is common. Some researchers argue that it is responsible for 23 percent of unexplained arterial thrombosis and 14 percent of the vein thrombosis, in which is not possible to identify a cause. Here a brief review on the available information on the sticky platelet syndrome and its importance in health is shown. In Cuba there are few reports of the clinical evaluation of patients with this condition, so further study to determine the extent of the disease is needed

Evaluación de factores predisponentes para el sangrado mediastinal en cirugía de revascularización miocárdica: Papel del ácido acetilsalicílico, otros antiagregantes plaquetarios, y anticoagulantes / Evaluation of Predisposing Factors for Mediastinal Bleeding in Myocardial Revascularization Surgery: Role of Acetylsalicylic Acid, Other Platelet Adhesion Inhibitors, and Anticoagulants

Propósito del trabajo: Determinar los factores predisponentes para sangrados perioperatorios en cirugía de revascularización miocárdica y establecer el papel de ácido acetilsalicílico, otros antiagregantes plaquetarios, y anticoagulantes, en la ocurrencia de estos sangrados. Método: Se realizó un análisis multivariado de 251 pacientes sometidos a cirugía de revascularización miocárdica en el año 2002. Resultados: En la administración prequirúrgica de ácido acetilsalicílico no se encontró diferencia significativa para la ocurrencia de sangrado perioperatorio importante. No existió incremento significativo en la transfusión de unidades de paquetes globulares, plaquetas, crioprecipitados. Los pacientes con administración de heparina no fraccionada y de bajo peso molecular, tuvieron un sangrado transoperatorio significativamente mayor (p < 0.001) que los pacientes sin este fármaco. El empleo del resto de los fármacos estudiados, no incrementó la cantidad de sangrado ni la administración de hemoderivados. Conclusiones: No existe evidencia estadística que justifique suspender la administración de antiagregantes plaquetarios en los pacientes con síndromes coronarios urgentes o electivos, a quienes se les someta a cirugía de revascularización miocárdica. Sin embargo, resultaría conveniente suspender la administración de heparina no fraccionada y de bajo peso molecular, a pacientes sometidos a cirugía de revascularización miocárdica en forma electiva.

Objective: To determine the main factors for perioperative mediastinal bleeding during coronary artery by-pass grafting and to establish the role of acetylsalicylic acid, other inhibitors of platelet adhesion, and anticoagulants in its occurrence. Methods: A multivariate analysis was performed to the data obtained from 251 patients subjected to coronary artery by-pass grafting in the year 2002. Results: There were no significant differences for the occurrence of perioperative bleeding induced by the preoperative administration of acetylsalicylic acid. No significant increment in the need for blood, platelet, or cryoprecipitates transfusion existed. Patients receiving non-fractionated or low molecular weight heparin had a significantly greater (p < 0.001) transoperative bleeding than patients without this drug. Administration of the other studied drugs did not increase either mediastinal bleeding or the need for blood derivatives. Conclusions: No statistical evidence was found to suspend administration of inhibitors of platelet adhesion in patients with coronary syndromes, subjected to coronary artery by-pass grafting. However, data obtained suggest the convenience of suspending administration of low molecular weight or non-fractionated heparin to patients subjected electively to coronary artery by-pass grafting.

INFLUNCE OF GELATIN AND DEXTRAN ON PLATELET vWF AND Ⅰb/Ⅰx / 解放军医学杂志

To investigate the effects of platelet glycoproteins after infusion of four kinds of solutions in vivo (30ml/kg), 105 patients for selective cholecystectomy were randomly divided into four groups.Normal saline was infused in group A patients,dextran 70 for group B, urea linked gelatin for group C, and modified fluid gelatin for group D. Blood samples from patients were taken before the infusion and two hours and three hours after the infusion for the measurement of platelet adhesion(PAdT), vonWillebrand factor (vWF), and glycoproteinⅠb/Ⅰx (GPⅠb/Ⅰx). As compared with other groups the level of vWF and GPⅠb/Ⅰx decreased significantly in group B( P

Effects of extracts of ginkgo biloba leaves on platelet adhesion and thrombosis / 中国临床药理学与治疗学

Aim To observe the effect of extracts of ginkgo biloba leaves(GbE) on platelet adhesion and thrombosis. Methods The platelet adhesion was assayed by rotating glass-globe method. The thrombogenesis method in artery-vein bypass was applied to observe thrombosis in vivo. The Chandler method was applied to induce thrombosis in vitro.The tail bleeding time was recorded by shearing tail method.Results GbE significantly decreased platelet adherence rate in rabbits, decreased the weight of thrombus produced in artery-vein bypass in rabbits, shortened the length and reduced dry weight of thrombus of rats in vitro,prolonged the tail bleeding time in mice.Conclusion GbE inhibits the platelet adhesion and thrombosis.

EFFECTS OF THIOPROLINE ON THROMBUS FORMATION AND PLATELET FUNCTION / 中国药理学通报

Effects of thioproline on thrombus formation and platelet function were studied. Thioprolline given in vitro ( 1 g/L ) or ex vivo ( iv 25mg /kg ) shortened length of thrombi and decresed the wet and dry weight of thrombi in rabbits or rats. Thioproline given iv vitro ( 1 g/L ) or ex vivo ( iv 50mg/kg ) inhibited platelet adhesion and aggregation induced by ADP in rabbits.

EFFECT OF CORYDALIS AMABILIS MIGO TOTAL ALKALOID ON FUNCTION OF PLATELETS IN RATS / 中国药理学通报

Corydalis amabilis Migo total alkaloid (COAMTA) given in vitro or in vivo caused an inhibition on ADP-induced blood platelet aggregation. In vitro, COAMTA 15.6, 31.3 & 62.5 ?g/ml PRP showed their inhibitory rates of 8.2, 32.0, & 36.8%. In vivo, at 10, 20, 40 min after iv COAMTA ( 0.6 mg/kg ) , the rates of inhibition were 40, 62.8, 24%.The thrombi formed in vitro were measured also. The results showed that COAMTA given in vitro or in vivo reduced the length and weight of thrombus, at same time, reduced rat platelet adhesion.A carotid-jugular extracorporeal shunt was made in the rats. A 6cm length of silk thread was placed in the shunt. 15 min after the restoration of blood flow in the shunt, the Wet weight of thrombus developed on the thread was measured.The thrombus weight was significantly reduced when COAMTA was given iv 0.3, & 0.6 mg/kg, im 0.9 mg/kg & po 1.5 mg/kg. The thrombus weight of control group was 26.1?0.7, but that of the medicated group was 8.9?1.7, 18.0?1.3, 16.4?0,6 a & 19.7?0.7 mg. The inhibitory rates were 66.1, 31.3, 37.2, & 28.4%.