OBJECTIVE: To examine the antiplatelet and antithrombotic activity of Rumex acetosella extract. METHODS: Standard light aggregometry was used for platelet aggregation, intracellular calcium mobilization assessed using Fura-2/AM, granule secretion (ATP release) by luminometer, and fibrinogen binding to integrin α_IIbβ₃ detected using flow cytometry. Western blotting is carried out to determine the phosphorylation of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Akt signaling. RESULTS: Rumex acetosella displayed the ability to inhibit platelet aggregation, calcium mobilization, granule secretion, and fibrinogen binding to integrin α_IIbβ₃. Rumex acetosella has also down-regulated MAPK and PI3K/Akt phosphorylation (all P<0.01). CONCLUSION Rumex acetosella extract exhibits antiplatelet activity via modulating GPVI signaling, and it may protect against the development of platelet-related cardiovascular diseases.
Blood Platelets/metabolism* ; Calcium/metabolism* ; Fibrinogen/metabolism* ; Mitogen-Activated Protein Kinases/metabolism* ; Phosphatidylinositol 3-Kinase/pharmacology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Phosphorylation ; Plant Extracts/pharmacology* ; Platelet Aggregation ; Platelet Aggregation Inhibitors/pharmacology* ; Platelet Glycoprotein GPIIb-IIIa Complex/pharmacology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Rumex/metabolism*

OBJECTIVETo observe the effect of Tongxinluo Capsule on platelet activities and vascular endothelial functions as well as prognosis in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) at different stages.

METHODS160 patients with acute coronary syndrome were randomly assigned to Tongxinluo (TXL) group (80 patients) and the conventional treatment group (80 patients). And 50 healthy subjects were set up as the health control group. Patients' plasma platelet activating factors (CD62p, CD63), and glucose protein (GP) IIb/IIIa, and endothelium-1 (ET-1), von Willebrand factor (vWF), nitric oxide (NO) levels, and endothelium dependent flow-mediated dilatation (FMD) were detected respectively. Patients in the TXL group orally took TXLC for six months. The aforesaid indices were re-detected in all patients after two months and six months. Comparison between before and after treatment in the same group and inter-group comparison were performed in the two groups.

RESULTSCompared with the health control group, CD62p, CD63, GPIIb/IIIa, vWF, and ET-1 levels increased significantly in ACS patients after PCI (all P<0.01), NO and FMD significantly decreased (P<0.01). CD62p, CD63, GPIIb/IIIa and, vWF also increased, and FMD decreased after PCI (all P<0.05), but insignificant difference was found in ET-1 and NO (P>0.05). In the TXL group and the conventional treatment group, the levels of CD62p, CD63, GPIIb/IIIa, vWF and ET-1 decreased significantly (P<0.05, P<0.01), NO and FMD increased (P<0.05, P<0. 01) when compared with before treatment. Compared with the conventional treatment group, the decrement of CD62p, CD63, GPIIb/IIIa and vWF (P<0.05, P<0.01), and the increment of FMD and NO (both P<0.05) were more obvious in the TXL group. The aforesaid indices were more obviously different between 6-month treatment and 2-month treatment in the TXL group and the conventional treatment group (P<0.05, P<0.01). Seven patients suffered from angina, six from heart failure, three from ventricular tachycardiac (VT)/ventricular fibrillation (VF), and two died suddenly in the conventional treatment group after six months of treatment, while only one suffered from angina, one from heart failure, and none from VT/VF or died suddenly in the TXL treatment group after 6 months of treatment.

CONCLUSIONTXL could be used in the prevention and treatment of coronary thrombosis, protect the vascular endothelial functions, as well as improve the prognosis of ACS patients after PCI.

Acute Coronary Syndrome ; blood ; therapy ; Aged ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Humans ; Male ; Middle Aged ; Nitric Oxide ; blood ; Percutaneous Coronary Intervention ; Platelet Activation ; drug effects ; Platelet Glycoprotein GPIIb-IIIa Complex ; metabolism ; Prognosis ; von Willebrand Factor ; metabolism

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

It is generally accepted that tissue factor plays an important role in coagulation and intravascular thrombus formation. Tissue factor is not only found primarily on the surface of certain cells that are located outside the vasculature, but also found in circulating cells. Monocyte express tissue factor induced by endotoxin. Recently, many researches indicate that P-selectin, CD40 ligand and GPIIb/IIIa receptor of platelet can also affect expression of tissue factor by monocyters. In addition, a lot of studies showed that tissue factor exist in the circulation including contained platelet. Tissue factor in the platelet releases under certain condition, and initiates coagulation. In this review the relation between platelet and tissue factor was elaborated.
Blood Platelets ; drug effects ; metabolism ; physiology ; CD40 Ligand ; physiology ; Humans ; Monocytes ; drug effects ; metabolism ; P-Selectin ; physiology ; Peptides ; pharmacology ; Platelet Glycoprotein GPIIb-IIIa Complex ; physiology ; Thromboplastin ; biosynthesis ; drug effects ; physiology

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid ; pharmacology ; Adolescent ; Adult ; Blood Platelets ; metabolism ; Calcium ; metabolism ; Chloride Channels ; antagonists & inhibitors ; Cytosol ; metabolism ; Dose-Response Relationship, Drug ; Female ; Humans ; Male ; Niflumic Acid ; pharmacology ; Oligopeptides ; pharmacology ; Platelet Aggregation ; drug effects ; Platelet Glycoprotein GPIIb-IIIa Complex ; antagonists & inhibitors

To investigate the changes of platelet activated state and platelet activated function by trace whole blood flow cytometry (FCM), and to explore the mechanism of hemorrhage and infiltration in adults with acute leukemia, the expression percentage and changes of these expressions of CD62p and PAC-1 on platelet surface were determined by FCM of trace whole blood after platelet activated by ADP in patients with new diagnosed AL (group I), complete remission (CR, group II) and continuously complete remission (CCR, group III). Healthy adults were used as control group. The result showed that the expression of CD62p in group I and II was higher than that in control group, before and after platelet activated by ADP (P < 0.01). The expression of PAC-1 in group I was higher than that in control group (P < 0.01), the expression of PAC-1 in group II was lower than that in control group (P > 0.01), There was no significant difference in expression of CD62p and PAC-1 between group III and control group (P > 0.01), and no significant difference was found between AL group with megakaryocyte malignant pathological changes and AL group without megakaryocyte malignant pathological changes before platelet activated by ADP (P > 0.01). After platelet activated by ADP, the expression of PAC-1 in the former was lower than that in the latter (P < 0.01). It is concluded that (1) high level activated platelet in peripheral blood of AL patients show that interaction between activated platelet and leukemia cells can be one of reason resulting in widespread hemorrhage and infiltration AL patiens; (2) the decrease of number and activted function of platelet at the first stage of AL patients may be caused by malignant hyperplasia of leukemia cells and damage of megakaryopoiesis in bone marrow.
Acute Disease ; Adenosine Diphosphate ; pharmacology ; Adolescent ; Adult ; Aged ; Blood Platelets ; cytology ; metabolism ; Cell Membrane ; drug effects ; metabolism ; Female ; Flow Cytometry ; Humans ; Leukemia ; blood ; pathology ; Male ; Middle Aged ; P-Selectin ; biosynthesis ; Platelet Activation ; drug effects ; physiology ; Platelet Glycoprotein GPIIb-IIIa Complex ; biosynthesis

OBJECTIVEBy observing the effect of API 0134, an active ingredient of green chiretta, on platelet membrane glycoprotein (GP) in patients with hyperlipemia to explore the mechanism of the anti-platelet aggregation effect of API.

METHODSThe mean immunofluorescent intensity (MFI) of the platelet membrane glycoprotein GP II b/III a, GPIb, P-selectin (GMP-140) and von Willebrand's factor (vWF) in resting platelet, activated platelet (untreated or treated with API 0134 of different concentrations) were detected in 30 randomly selected patients with hyperlipemia, using immunofluorescent marker and flow cytometry.

RESULTSAPI of all concentrations (25 mg/L, 50 mg/L and 100 mg/L) could significantly decrease the MFI of GP II b/III a in a positive dose-dependent manner, as compared with that in activated platelet untreated with API; API of 50 mg/L and 100 mg/L could also reduce the MFI of GMP-140 and vWF in activated platelet (P < 0.01); but API of 100 mg/L showed insignificant influence on GPIb expression in activated platelet membrane.

CONCLUSIONAPI 0134 exerts obvious anti-platelet GP II b/III a effect on activated platelets, middle or large dose of API also shows inhibiting effect on GMP-140 and vWF expression in platelet.

Aged ; Andrographis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Humans ; Hyperlipidemias ; blood ; drug therapy ; Male ; Middle Aged ; P-Selectin ; blood ; Phytotherapy ; Platelet Glycoprotein GPIIb-IIIa Complex ; metabolism ; von Willebrand Factor ; metabolism

OBJECTIVETo prepare a single chain antibody (ScFv) of mAb SZ-21 against platelet GPIIIa for its future clinical application.

METHODSThe expression vector pET20b-SZ-21ScFv was constructed and the fusion protein was expressed in E. coli BL21 (DE3) PlysS. The activated fusion protein was obtained after a series of purification steps, including cell breakage, inclusion body solubilization, His-bind resin affinity chromatography and protein refolding.

RESULTSThe fusion protein yields were up to 21% of the total amount of bacteria protein. The ScFv fragment could inhibit ADP-induced platelets aggregation in a dose-dependent manner in vitro and the maximal inhibition rate was obtained at a concentration of 20 micro g/ml. It also reacted with endothelial cells as detected by flow cytometry. Moreover, the ScFv fragment was able to inhibit the binding of fibrinogen to platelet.

CONCLUSIONThe SZ-21ScFv fragment had the activity to inhibit platelets aggregation and the binding of fibrinogen to platelet, being potentially useful for the treatment of thrombotic diseases.

Antibodies, Monoclonal ; pharmacology ; Blood Platelets ; metabolism ; Endothelium, Vascular ; cytology ; Fibrinogen ; metabolism ; Humans ; Immunoglobulin Fragments ; pharmacology ; Platelet Aggregation ; Platelet Glycoprotein GPIIb-IIIa Complex ; immunology ; Recombinant Fusion Proteins ; isolation & purification ; pharmacology

To investigate the effect of GST-KGDX (glutathione S-transferase-Lys-Gly-Asp-X) fusion protein, GP IIb/IIIa receptor antagonist, on platelet function in vitro. The KGDX (Lys-Gly-Asp-X) gene was assembled from 2 synthetic oligonucleotides, 36 bp in length, using BamH I and Xho I restriction enzyme sites at the end of the gene for cloning into the expression vector pGEX4T-1. Expression of fusion protein was directed by the tac promoter. The Escherichia coli DH5a contained the plasmid pGEX-4T-1-KGDX was expressed by 37 degrees C heat induction. The fusion protein of KGDX with glutathione S-transferase (GST-KGDX) was purified in one step from the bacterial lysate by glutathione-agarose beads for affinity chromatography. GST-KGDX was found to be soluble and abundant, the yield of 35 mg/L of cultures was obtained. The GST-KGDX was expressed in E. coli to a level of 48.02% of total cellular protein. GST-KGDX inhibited ADP-induced human platelet aggregation stronger than GST (P < 0.05 or < 0.01). In flow cytometry assay for fibrinogen binding, both GST and GST-KGDX inhibited platelet aggregation by binding with high affinity to GPIIb/IIIa. Mean fluorescence intensity of GST-KGDX fusion protein was significantly higher than that of GST. It is concluded that the GST-KGDX fusion protein can be produced by E. coli and used as an antiplatelet agent.
Adult ; Escherichia coli ; genetics ; Female ; Fibrinogen ; metabolism ; Flow Cytometry ; Glutathione Transferase ; pharmacology ; Humans ; Male ; Oligopeptides ; pharmacology ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; isolation & purification ; pharmacology ; Platelet Glycoprotein GPIIb-IIIa Complex ; antagonists & inhibitors ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; isolation & purification ; pharmacology