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

Platelets play a key role in the pathogenesis of atherothrombosis, and also perform the physiological hemostasis. The platelet function assays have values in the investigating patients with suspected platelet disorders and in studying the effects of anti-platelet drugs. There are increasing assays for investigating platelet function, including assessment of platelet adhesion, activation and aggregation, etc. However, all of these assays have certain limited sensitivity. It is necessary to develop a simple, sensitive assay that measures the activated platelet. This article reviewed advances of researches on platelet function assays, including assay for general function of platelet, assay of platelet adhesion function, platelet activation assay, platelet aggregation assay, platelet coagulation assay and application of flow cytometry in assessment of platelet functions, etc. and looked forward to research prospect in this field.
Blood Platelets ; physiology ; Humans ; Platelet Activation ; physiology ; Platelet Adhesiveness ; physiology ; Platelet Aggregation ; physiology ; Platelet Function Tests ; methods ; trends

AIMTo study the antagonistic effect of myricetin on platelet activing factor (PAF).

METHODSThe specific binding of [3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique.

RESULTSThe specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in [3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1.

CONCLUSIONThe specific receptor binding of PAF can be antagonized by myricetin.

Animals ; Calcium ; metabolism ; Flavonoids ; pharmacology ; Male ; Neutrophils ; metabolism ; Platelet Activating Factor ; antagonists & inhibitors ; metabolism ; Platelet Activation ; drug effects ; Platelet Adhesiveness ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Platelet Membrane Glycoproteins ; metabolism ; Rabbits ; Receptors, G-Protein-Coupled ; metabolism

These active components and monomes inhibit thrombosis aimed directly at activation, adhesiveness and aggregation of platelet, thus preventing and curing ischemic cardiovascular and cerebrovascular diseases. Here we summarized the effect of active components and monomes of the traditional Chinese medicine targeted platelet on ischemic cardiovascular and cerebrovascular diseases, to provide references for drug investigation and clinical application.
Alkaloids ; isolation & purification ; pharmacology ; Animals ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Flavones ; isolation & purification ; pharmacology ; Humans ; Plants, Medicinal ; chemistry ; Platelet Activation ; drug effects ; Platelet Adhesiveness ; drug effects ; Platelet Aggregation ; drug effects ; Terpenes ; isolation & purification ; pharmacology

BACKGROUND: We evaluate the efficacy of ultra-hydrophilic coated bypass circuits in comparison with uncoated bypass circuits in a porcine cardiopulmonary bypass model. MATERIAL AND METHOD: Normothermic cardiopulmonary bypass was performed in 10 anesthetized pigs via the left atrium and ascending aorta with a centrifugal biopump. Ultra-hydrophilic coated bypass circuits were used in 5 pigs (the study group) and uncoated bypass circuits were used for the control group. Platelet counts and platelet aggregation tests were performed. The thrombin-antithrombin (TAT) complex level and total protein level were evaluated. RESULT: There were no significant changes in the platelet counts and aggregation ability of both groups. The TAT complex levels were not different between the two groups. The total protein level was significantly lower in the control group after cessation of cardiopulmonary bypass. CONCLUSION: The clinical effects of ultra-hydrophilic coating circuits were not remarkable, in terms of reducing inflammatory reaction and protection of platelet function. However, the effect of protection for blood protein adsorption might be acceptable.
Adsorption* ; Aorta ; Blood Platelets* ; Cardiopulmonary Bypass ; Heart Atria ; Platelet Activation* ; Platelet Aggregation ; Platelet Count ; Swine

Hemocompatibility is an important component of biocompatibility; it reflects the degree of interaction between material and blood. Hemocompatibility is multifaceted, so that the material's impact on the blood and the underlying mechanism are very complicated. This article presents a review of researches probing the impact of material on blood via contact activation and plasma protein adsorption; via the platelet activated and the formation of thrombin; via the complement system activated and the activation of leukocytes as well as other mechanisms of hemolysis. The current methods for evaluation and the future trend of development are also introduced.
Biocompatible Materials ; standards ; Blood ; Humans ; Materials Testing ; methods ; Platelet Activation ; Platelet Adhesiveness ; Stress, Mechanical ; Surface Properties ; Thrombin ; analysis

BACKGROUND: Platelet activation has an important role in the progression of atheroclerosis and acute ischemic events. In this study, in order to know the significance of platelet functions in a large artery atherosclerotic infarction, we evaluated the serial changes of platelet aggregability in patients with a large artery atherosclerotic infarction. METHODS: We serially (within 24 hrs, at 72 hrs, and 7 days) measured the extents of platelet aggregation to ADP and collagen in 43 patients with acute ischemic stroke (LAA-22, SVD-21) and compared them with those in patients with asymptomatic carotid stenosis (n=20) and in normal controls (n=24). RESULTS: The extents of platelet aggregation to ADP and collagen were significantly increased in large artery atherosclerotic infarctions compared to small vessel disease. These differences of platelet aggregability between the two groups were maintained for seven days after an ischemic event. However, the platelet aggregability was not different between large artery atherosclerotic infarctions and asymptomatic carotid stenosis. CONCLUSIONS: This data suggests that increased platelet aggregability is important in large artery atherosclerotic infarction and is caused by pre-existing atherosclerotic changes rather than acute ischemic events.
Adenosine Diphosphate ; Arteries ; Atherosclerosis ; Blood Platelets* ; Carotid Stenosis ; Collagen ; Humans ; Infarction ; Platelet Activation ; Platelet Aggregation* ; Stroke*

Platelet lineage suggests that it plays a crucial role in immune responses. In recent years, many studies have found that platelet activation is closely related to the activity of inflammatory bowel disease. Activated platelets can release inflammatory mediators, and express surface molecules that mediate inflammation, interact with leukocytes and vascular endothelial cells. It provides a theoretical basis for antiplatelet drugs to treat the inflammatory bowel disease.
Blood Platelets ; Endothelial Cells ; Humans ; Inflammatory Bowel Diseases ; Platelet Activation ; Platelet Aggregation Inhibitors

This study was aimed to investigate the effect of prefreezing parameters such as freezing rate, annealing, rate, annealing temperature, holding time in annealing before lyophilization on lyophilized platelets by orthogonal tests. The recovery rate, the morphological and ultrastructural changes, the activation and aggregation of lyophilized platelet after rehydratation were detected by cytometer, scan electron microscopy, flow cytometry and aggregation reaction on thrombin, respectively, and complex evaluation was carried out. The results showed that the recovery rate of lyophilized platelets was 91% - 53.5% at different conditions of lyophilization, the size and shape of ice crystals in lyophilized platelets of different test groups were not similar, the expression and distribution of platelet activation markers (PAC-1 and CD62p) after rehydration were relatively similar to fresh platelets, expression rate of PAC-1 was lower (0.03% - 0.22%), meanwhile there were differences of CD62p expression levels between different groups. The optimal theoretic composition of prefreezing conditions obtained on basis of platelet recovery rate was A(2)B(1)C(1)D(3), i.e, first, suspensions of platelets on the program control cooling apparatus were lyophilized with a rate of 20 degrees C/min and maintained at -40 degrees C for 2 hours, then the annealing was conducted at -30 degrees C for 0.5 hours with a heating rate of 1.5 degrees C/min; finally, the freeze-drying program was carried out to the end. It is concluded that the freezing rate, annealing rate, annealing temperature and holding time of annealing all impact on the recovery of lyophilized platelets. The preservation qualities of lyophilized platelets were affected by the various combinations of prefreezing parameters.
Blood Platelets ; Blood Preservation ; methods ; Cell Survival ; Cryopreservation ; methods ; Freeze Drying ; methods ; Humans ; Platelet Activation ; Platelet Aggregation ; Platelet Count

This study was purposed to explore the mechanism of cooked blanched garlic leave juice against platelet aggregation. The juice of blanched garlic leaves was mixed with platelet rich plasma (PRP), the human platelet aggregation, the activation of human platelets induced by adenosine diphosphate (ADP) and collagen were observed; the expression levels of the activated platelets (Fib-R) and P-selectin (CD62P), and the amount of platelet fibrinogen binding were detected by flow cytometry; 10 rabbits were randomly divided into two groups, in addition to the normal diet, they were fed with physiologic saline and cooked blanched garlic leave juice respectively. After 1, 3, 5 , 8 weeks, the maximum ratio of rabbit platelet aggregation induced by ADP and collagen were observed . The results showed that the cooked blanched garlic leave juice could significantly inhibit human platelet aggregation induced by ADP and collagen (P < 0.05), the inhibitory ratio were 87.37% and 86.24% respectively; the juice could not inhibit activated platelets Fib-R and CD62P expression levels (P > 0.05), but was able to inhibit platelet fibrinogen binding capacity (P < 0.05); the rabbit platelet aggregation rate in the group given cooked blanched garlic leave juice was significantly lower than that in control group (P < 0.05). It is concluded that the cooked blanched garlic leave juice can inhibit platelet aggregation in vitro and in vivo, the inhibition of aggregation pathway mainly is blocking the combination of fibrinogen with Fib-R, which finally results in the inhibition of platelet aggregation. Therefore, regular consumption of cooked blanched garlic leaves may prevent cardiovascular thrombotic diseases.
Adult ; Aged ; Animals ; Female ; Garlic ; chemistry ; Humans ; Male ; Middle Aged ; Plant Leaves ; chemistry ; Platelet Activation ; Platelet Aggregation ; Platelet Function Tests ; Platelet-Rich Plasma ; Rabbits ; Young Adult