Objective To examine the antiplatelet effect of ticagrelor by microfluidic chip and flow cytometry under shear stress in vitro. Methods Microfluidic chip was used to examine the effect of ticagrelor on platelet aggregation at the shear rates of 300/s and 1500/s.We adopted the surface coverage of platelet aggregation to calculate the half inhibition rate of ticagrelor.The inhibitory effect of ticagrelor on ADP-induced platelet aggregation was verified by optical turbidimetry.Microfluidic chip was used to construct an in vitro vascular stenosis model,with which the platelet reactivity under high shear rate was determined.Furthermore,the effect of ticagrelor on the expression of fibrinogen receptor (PAC-1) and P-selectin (CD62P) on platelet membrane activated by high shear rate was analyzed by flow cytometry. Results At the shear rates of 300/s and 1500/s,ticagrelor inhibited platelet aggregation in a concentration-dependent manner,and the inhibition at 300/s was stronger than that at 1500/s (both P<0.001).Ticagrelor at a concentration ≥4 μmol/L almost completely inhibited platelet aggregation.The inhibition of ADP-induced platelet aggregation by ticagrelor was similar to the results under flow conditions and also in a concentration-dependent manner.Ticagrelor inhibited the expression of PAC-1 and CD62P. Conclusion We employed microfluidic chip to analyze platelet aggregation and flow cytometry to detect platelet activation,which can reveal the responses of different patients to ticagrelor.
Humans ; Ticagrelor/pharmacology* ; Platelet Aggregation Inhibitors/pharmacology* ; Flow Cytometry/methods* ; Microfluidics ; Platelet Aggregation

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.
Humans ; Microfluidics ; Platelet Adhesiveness ; Platelet Aggregation ; Blood Platelets/metabolism* ; Platelet Aggregation Inhibitors/pharmacology* ; Platelet Activation/physiology* ; Thrombosis

Chemical constituents of Leonurus japonicus were isolated and purified by a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, MCI, and Rp C18. Structures of the isolates were determined by spectroscopic analysis as 10 coumarins: bergapten (1), xanthotoxin (2), isopimpinellin (3), isogosferal (4), imperatorin (5), meransin hydrate(6), isomeranzin(7), murrayone(8) , auraptenol(9), and osthol(10). In addition to compound 9, the others were isolated from the genus Leonurus for the first time. In the in vitro assay, compounds 4 and 8 significantly inhibited the abnormal increase of platelet aggregation induced by ADP.
Blood Platelets ; drug effects ; Coumarins ; chemistry ; pharmacology ; Leonurus ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; chemistry ; pharmacology

OBJECTIVETo investigate the expression of mDia1 (mammalian diaphanous 1)in platelet and the role of mDia1 or phosphatidylinositol 3-kinase (PI3K) in the process of thrombin-induced platelet aggregation.

METHODSThe extent of platelet aggregation was measured by a platelet aggregation system and the expression of mDia1 and its relation with F-actin in quiescent, spreading or aggregated platelets by Western blot.

RESULTSThere was no significant difference in mDia1 expression level between quiescent and activated platelets. mDia1 moved from a Triton-X100-soluble cytosolic fraction to insoluble cytoskeleton fraction after thrombin induced platelets aggregation. Anti-mDia1 antibody could inhibit this aggregation. PI3K inhibitor Wortmannin or Ly294002 inhibited the thrombin induced platelet aggregation and the above mentioned mDia1 translocation.

CONCLUSIONPI3-kinase mediates the thrombin-induced platelet aggregation through mDia1 pathway.

Actins ; Animals ; Blood Platelets ; metabolism ; Humans ; Phosphatidylinositol 3-Kinases ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; pharmacology ; Thrombin ; pharmacology

BACKGROUND: Resveratrol has been shown to inhibit platelet aggregation. However, the mechanism for this action of resveratrol remains to be clarified. The purpose of this study was to elucidate the Ca METHODS: Ca RESULTS: Thapsigargin-induced Ca CONCLUSIONS The results suggest that resveratrol inhibits thrombin-induced platelet aggregation through decreasing Ca
Antioxidants/administration & dosage* ; Calcium/physiology* ; Humans ; Platelet Aggregation/drug effects* ; Platelet Aggregation Inhibitors/pharmacology* ; Resveratrol/pharmacology* ; Signal Transduction/drug effects*

The thrombus is a deposit that is formed on the surface of the endovascular or at the site of repair,and known as the main complication of cardiovascular disease and the cause of death. At the same time,thrombus is mainly treated by the following three ways: anticoagulation,anti-platelet aggregation and thrombolysis. In this study,the chemical constituents of seven traditional Chinese medicines in the Xixian Tongshuan Preparation were collected to construct a component database. Subsequently,the pharmacophore were used to screen out the component database,and molecular docking was used to screen out the results of pharmacophore for explaining the material basis and mechanism that Xixian Tongshuan Preparation exerts anti-thrombotic activity by inhibiting platelet aggregation. First of all,P2 Y12,GPⅡb/Ⅲa and PAR1 were selected as study vectors,the optimal models of inhibitors were obtained respectively through verification and evaluation of the pharmacophore models. Afterwards,the component database was screened out by the optimal pharmacophore models of PAR1,P2 Y12 and GP Ⅱ b/Ⅲ a,and the molecular docking method was used to further refine the screening results. The screening results indicated that the anti-platelet aggregation effect of Xixian Tongshuan Preparation was correlated with the inhibition of P2 Y12,PAR1 and GPⅡb/Ⅲa expressions with saffower yellower,hirudin and candidin and notoginseng triterpenes,folinic acid,respectively. The material basis and mechanism of anti-platelet aggregation of Xixian Tongshuan Preparation provided a theoretical basis for the clinical use of the preparation and the lead compounds for the development of anti-platelet aggregation drugs.
Databases, Pharmaceutical ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Molecular Docking Simulation ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; pharmacology ; Thrombosis

Batifiban, a synthetic cyclic peptide, is a potent platelet glycoprotein GPIIb/IIIa antagonist which may be useful in the treatment and prevention of acute coronary syndromes. The pharmacokinetics and pharmacodymanic (inhibition of platelet aggregation) effects, and tolerability of batifiban were investigated in healthy subjects following single bolus injection with doses of 55, 110, or 220 microg/kg, or multiple doses of an bolus followed intravenous infusion for 24 h (180 microg/kg plus 2.0 microg/min.kg, and 220 microg/kg plus 2.5 microg/min.kg) in this phase I clinical trial. Plasma levels of batifiban and areas under the curve were found to be proportional to doses. Batifiban was rapidly eliminated with a half-life of approximately 2.5 h. Significant differences were noted for plasma levels of batifiban and areas under the curve between males and females. No significant differences in the terminal half-life were found between males and females. Batifiban reversibly inhibited ex vivo platelet aggregation in a dose- and concentration-dependent manner, consistent with its mechanism as a GPIIb/IIIa antagonist. Single and multiple intravenous doses of batifiban were found to be safe and well tolerated in healthy subjects. These results support a bolus injection plus intravenous infusion regimen of batifiban for the treatment and prevention of acute coronary syndromes.
Injections, Intravenous ; Peptides, Cyclic/*pharmacokinetics ; Peptides, Cyclic/*pharmacology ; Platelet Aggregation Inhibitors/adverse effects ; Platelet Aggregation Inhibitors/*pharmacokinetics ; Platelet Aggregation Inhibitors/*pharmacology ; Platelet Glycoprotein GPIIb-IIIa Complex/*antagonists & inhibitors ; Young Adult

Platelet function tests have been increasingly used to assist in the diagnosis of platelet disorders and prethrombotic state, monitoring of the efficacy of antiplatelet therapies, and personalized treatment. On the basis of light transmission aggregometry, new methods for platelet function test have been developed successively. At present, the research and development of platelet function detector is in its infancy in China. The active constituents of antiplatelet Chinese medicines can be classified into terpenoids, flavonoids, saponins, organic acids, lignans, diketones, volatile oils, and stilbenes. The results of dose-antiplatelet effect relationship of Chinese medicines and the active constituents showed that the effective concentration of the extracts or monomers of Chinese medicines was at micromolar level(μmol·L~(-1)), among which salvianolic acid B and ginkgolide K, ginkgolide B, and ginkgolide A had the strongest antiplatelet effect. These results suggest that the antiplatelet effect of Chinese medicine may be weaker than that of chemical drugs and biological products. Therefore, it is necessary to explore the structure-activity relationship of the active constituents in existing Chinese medicines and further improve their efficacy through structure modification. The antiplatelet effect of Chinese medicines and the constituents involves multiple pathways and multiple targets. These research results provide a reference for clinical application of them. However, there is still a lack of large-scale multi-center clinical trials to confirm the efficacy and safety of them. The regularity of the relationship between the structures of various constituents and their corresponding functions is still unknown and the relevant signal transduction pathways and structure-activity relationship need to be further studied. This paper summarized and analyzed the determination methods of platelet functions and the research results of antiplatelet Chinese medicines, which is of reference value for the research of effective and safe antiplatelet Chinese medicines.
Biological Products ; China ; Medicine, East Asian Traditional ; Platelet Aggregation Inhibitors/pharmacology* ; Platelet Function Tests

The purpose of study was to investigate the effects of L-arginine and cilostazol on platelet-activation and aggregation reserve in vitro, so as to provide proof for selecting reversible activation-inhibitors for platelets lyophilization. Activation and function of platelets were investigated by using flow cytometry with the CD62p and PAC-1 expression and re-expression after being activated by thrombin, and by means of platelet aggregation reaction to thrombin, ADP and propyl gallate, as well as coagulation activity of platelets. The results showed that expression of CD62p and PAC-1 increased after being pretreated. Both L-arginie and cilostazol could inhibit CD62p and PAC-1 expression and related with their concentrations. Cilostazol had an intensive inhibition effect on expressions of CD62p and PAC-1 induced by thrombin, and the inhibition increased when concentration augmented. L-arginine had the same effects on PAC-1, but had no effects on CD62p. L-arginine and cilostazol inhibited aggregation induced by thrombin, ADP and propyl gallate, and the inhibitions were related directly with dosage. When L-arginine concentration was higher or equal to 15 mmol/L, or cilostazol concentration was in range of 1 - 4 mmol/L, the aggregation time were prolonged so much or even no aggregation. It is concluded that when L-Arginine concentration is 5 mmol/L and 10 mmol/L, platelet activation can be inhibited, but aggregation ability and characters keep intact. Concentration at 5 mmol/L may be the best. 1 mmol/L of cilostazol can inhibit activation in vitro and retain part of platelet ability of aggregation and reexpression.
Arginine ; pharmacology ; Blood Platelets ; metabolism ; Humans ; P-Selectin ; drug effects ; metabolism ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Tetrazoles ; pharmacology

Berbamine (molecular formular C37H40N2O6) is a bi-benzle-isoquinolyl alkaloid extracted from Berberis poiretil Schneid (genus of Berberis, family of Beridaceae), a kind of Chinese plants. In aspect of cardiovascular pharmacology, berbamine shows actions of anti-arrhythmia, anti-myocardial ischemia, vasodilatating to lower blood pressure, and antithrombosis, it could lower heart function and heart rate. Study on its anti-arrhythmia was the deepest one. The significant anti-arrhythmia action can be achieved by inhibiting ionic channels of sodium, potassium, calcium, etc., negative frequency and negative transduction, improving the diastolic excitation threshold of myocardium, prolonging effective refractory period of myocardium. As a direction of researches on new type of antiarrhythmic herbs and herbal drugs, the study on berbamine is worthy of further research and development.
Alkaloids ; pharmacology ; Anti-Arrhythmia Agents ; pharmacology ; Antihypertensive Agents ; pharmacology ; Benzylisoquinolines ; pharmacology ; Heart Rate ; drug effects ; Ion Channel Gating ; drug effects ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; pharmacology