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

OBJECTIVE: To explore the regulation of mitochondria on platelet apoptosis and activation, and the relationship between platelet apoptosis and activation. METHODS: Platelets were isolated from peripheral venous blood of healthy volunteers. Cyclosporin A (CsA), which has a protective effect on the function of platelet mitochondria, BAPTA, which can chelate calcium ions across membranes in platelets, and NAC, an antioxidant that reduces the level of intracellular reactive oxygen species, were selected for coincubation with washed platelets, respectively. By flow cytometry, platelet aggregator was used to detect the changes of platelet mitochondrial function and platelet activation indexes after different interventions. RESULTS: H89, staurosporine, and A23187 led to platelet mitochondrial abnormalities, while CsA could effectively reverse the decline of platelet mitochondrial membrane potential caused by them. Antioxidant NAC could reverse platelet mitochondrial damage correspondingly, and completely reverse platelet shrinkage and phosphatidylserine eversion induced by H89. BAPTA, prostaglandin E1, acetylsalicylic acid and other inhibitors could not reverse the decline of platelet mitochondrial membrane potential. CONCLUSION Mitochondrial function plays an important role in platelet apoptosis and activation. Abnormal mitochondrial function causes the imbalance of reduction/oxidation state in platelets, which leads to platelet apoptosis. Platelet apoptosis and activation are independent signal processes.
Humans ; Blood Platelets/metabolism* ; Antioxidants/pharmacology* ; Mitochondria/physiology* ; Platelet Activation ; Apoptosis ; Membrane Potential, Mitochondrial ; Reactive Oxygen Species/pharmacology*

Platelets, small pieces of cytoplasm with biological activity, split and fall off the megakaryocytes and mature from the bone marrow. After stimulated, platelets produce nitric oxide to inhibit their own activation and aggregation. Pathologically, the injury of endothelial cells activates platelets and changes their functions. The release of inflammatory mediators and cytokines induces and enhances the development and progression of atherosclerosis, and thereby promotes the occurrence of erectile dysfunction. Besides, platelets and their related functional parameters may serve as important indicators in the diagnosis and treatment of erectile dysfunction.
Atherosclerosis ; etiology ; Blood Platelets ; physiology ; Cytokines ; metabolism ; Endothelial Cells ; Erectile Dysfunction ; etiology ; Humans ; Male ; Nitric Oxide ; biosynthesis ; Platelet Activation

OBJECTIVETo investigate the effect of the anticoagulants on PRP quality, so as to clarify the appropriate anticoagulant used in PRP production.

METHODSThe microstructure change of platelets collected via heparin, citrate, acid citrate dextrose (ACD) and citrate-theophylline-adenosine-dipyridamole ( CTAD) was observed by TEM following time course. The extent of spontaneous activation of platelets in four groups was detected by measuring sP-selectin in plasma. The TGF-β1 release amount of activated PRP of four groups was measured.

RESULTSCTAD is superior to other anticoagulants in maintaining the integrity of platelet structures for a long time and preventing platelet spontaneous activation. ACD slightly surpassed heparin and citrate in above two aspects. ACD-PRP and CTAD-PRP released significantly more TGF-β1 compared with heparin and citrate.

CONCLUSIONSThe PRP quality and biological effects were strongly associated with the type of Anticoagulants. ACD and CTAD are optimal anticoagulants in PRP production for they can maintain platelet viability at a high level.

Adenosine ; pharmacology ; Anticoagulants ; pharmacology ; Blood Platelets ; drug effects ; physiology ; Citrates ; pharmacology ; Citric Acid ; pharmacology ; Dipyridamole ; pharmacology ; Drug Combinations ; Glucose ; analogs & derivatives ; pharmacology ; Heparin ; pharmacology ; Platelet Activation ; drug effects ; Platelet-Rich Plasma ; Theophylline ; pharmacology ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the relationship between platelet parameters and delayed graft function (DGF) early after kidney transplantation.

METHODSWe retrospectively analyzed the clinical data of 232 recipients within 2 months following kidney transplantation performed between January, 2009 and September, 2013, among whom 29 experienced DGF. The laboratory data of the preoperative and postoperative platelets were collected from all the recipients.

RESULTSCompared with the preoperative levels, the platelet number (PLT) and platelet hematocrit (PCT) were decreased on day 1 after kidney transplantation and was the lowest on day 5 (P<0.05), followed by gradual increase till reaching the highest levels on day 15 (P<0.05) and recovery of the preoperative level in days 30-60. The average platelet volume (MPV), platelet volume distribution width (PDW) and large platelet ratio (P-LCR) were increased on day 1, highest on day 7 (P<0.05), and reduced to the preoperative level on day 15, but then rose again slowly. MPV and P-LCR in days 30 to 60 and PDW in days 45 to 60 were significantly higher than the preoperative levels (P<0.05). The patients with DGF showed lowered PLT than those without DGF since day 2, and this difference was statistically significant in days 7 to 10, while PCT remained comparable between the two groups; MPV, PDW, and P-LCR were higher in DGF group than in DGF-free group with statistically significant difference on days 7, 10, and 15 (P<0.05).

CONCLUSIONPlatelet function is associated with postoperative renal graft function recovery, and platelet parameters can provide new markers for monitoring the occurrence and reversion of DGF.

Biomarkers ; Blood Platelets ; physiology ; Delayed Graft Function ; Humans ; Kidney Transplantation ; Platelet Activation ; Platelet Count ; Postoperative Period ; Retrospective Studies

Atherosclerosis ; complications ; pathology ; Blood Platelets ; physiology ; Humans ; Platelet Activation ; Thrombosis ; etiology ; pathology

OBJECTIVETo investigate the changes of endothelial function indices and their relation to platelet activation in patients with idiopathic atrial fibrillation (AF).

METHODSWe studied 61 patients with idiopathic AF with 34 age- and sex-matched healthy persons as control. Platelet counts in the blood were tested, and plasma levels of NOx were analyzed using Griess method. The plasma levels of von Willibrand factor (vWF) and soluble P-selectin (sP-selectin) were determined using enzyme-linked immunosorbent assay.

RESULTSCompared to healthy control, the patients with idiopathic AF had significantly lower levels of plasma NOx (18.2-/+7.3 vs 24.3-/+7.8 micromol/L, P=0.049) and higher levels of plasma sP-selectin (25.6-/+6.2 vs 22.4-/+4.8 ng/ml, P=0.007). No significant differences were found in the platelet counts or plasma vWF levels between the two groups. A significant inverse correlation was found between plasma NOx and sP-selectin (r=-0.405, P=0.025) in patients with idiopathic AF.

CONCLUSIONAF per se may impair the endothelial function and activate platelet function, suggesting the role of endothelial dysfunction in activated platelet function in AF patients.

Adult ; Aged ; Atrial Fibrillation ; blood ; Biomarkers ; blood ; Case-Control Studies ; Endothelium, Vascular ; physiology ; Female ; Humans ; Male ; Middle Aged ; Nitric Oxide ; blood ; P-Selectin ; blood ; Platelet Activation ; von Willebrand Factor ; analysis

CHO cells expressing human GPIb/IX and rabbit red blood cells coated with human von Willebrand factor (VWF) were adapted to our study on the binding probability and the detachment force of GPIb/IX and VWF. With the micropipette system, the two cells were impinged under a constant force for controlled time. When the cells were pulled apart, the deformation of RBC was recorded, and the binding score and detachment force of the proteins were determined. After the two cells were impinged into 0.5 microm for 30 s, the binding probability of the two cells carrying GPIb/IX and VWF was 15.0%. Via analyzing the deformation of red blood cells, we found out the distribution of rupture forces of cells with GPIb/IX and VWF. Therefore, we infer that the continuous distribution of the detachment force is due to the stochastic effect. The most probable value of the detachment force was 10 pN.
Animals ; Binding Sites ; Blood Platelets ; metabolism ; CHO Cells ; Cell Adhesion ; Cricetinae ; Cricetulus ; Humans ; Platelet Activation ; physiology ; Platelet Glycoprotein GPIb-IX Complex ; chemistry ; metabolism ; Rabbits ; von Willebrand Factor ; chemistry ; metabolism

The objective of study was to compare the influences of wortmannin on platelet aggregation and platelet membrane surface glycoproteins GPIb expression after thrombin receptor activation, and to investigate the role of phosphatidylinositol 3-kinase (PI3-K) and myosin light chain kinase (MLCK) in the course of thrombin receptor activation. Peptide SFLLRN (PAR1-AP) and AYPGKF (PAR4-AP) were used for stimulating platelet, and the changes of platelet aggregation and GPIb were analyzed with 100 nmol/L wortmannin (inhibitor of PI3-K) and 10 micromol/L wortmannin (inhibitor of MLCK). The results indicated that the platelet activation was influenced by either concentration of wortmannin in response to PAR stimulation. Platelet aggregation was apparently inhibited by 10 micromol/L wortmannin through both PAR peptides, and was slightly inhibited by 100 nmol/L wortmannin only under PAR1-AP activation. In addition, GPIbalpha internalization was partly inhibited by 100 nmol/L wortmannin in response to PAR1 (p < 0.05 at 1, 2, 5 min) and PAR4 (p < 0.05 at 2, 5, 10 min) activation. Meanwhile, 10 micromol/L wortmannin induced little change for GPIbalpha centralisation in the course of PAR activation, with a delayed restoration of surface GPIbalpha observed under PAR1-AP activation, and no change of GPIbalpha redistribution existed under PAR4-AP activation. It is concluded that the different roles of PI3-K and MLCK exist in the course of thrombin receptor activation. PI3-K accelerates the short course of GPIb centralisation for two PAR signal pathways, while MLCK inhibits the restoration of GPIbalpha in PAR1 pathway.
Adult ; Androstadienes ; pharmacology ; Female ; Humans ; Male ; Myosin-Light-Chain Kinase ; metabolism ; Phosphatidylinositol 3-Kinase ; metabolism ; Platelet Activation ; drug effects ; Platelet Aggregation ; Receptors, Thrombin ; metabolism ; physiology ; Signal Transduction

Animals ; Humans ; Hypertension, Pulmonary ; etiology ; Inflammation Mediators ; physiology ; Neutrophil Activation ; Platelet Activating Factor ; antagonists & inhibitors ; physiology ; Pulmonary Edema ; etiology ; Respiratory Distress Syndrome, Adult ; drug therapy ; etiology