OBJECTIVE: To evaluate the performance of a microfluidic platelet function test platform (MPFTP) previously established by our research group. METHODS: The effects of flow shear rate and storage time on platelet function test were analyzed taking the MPFTP as the object. The intra-assay variability of the MPFTP was evaluated. The function of platelet in peripheral venous blood from 24 healthy volunteers was assessed using the MPFTP and light transmission turbidity, either in the presence of 20 μmol/L acetylsalicylic acid (AS, an inhibitor of cyclooxygenase 1) or 50 μmol/L 5-phospho-2-methylthioadenosine (2-MeSAMP, a P2Y₁₂ receptor inhibitor). The diagnostic performance of both methods in assaying platelet function inhibition by AS and 2-MeSAMP was analyzed by using receiver operating characteristic (ROC) curve. RESULTS: Under the flow shear rate of 1 500 s^-1, our MPFTP could dynamically monitor platelet adhesion and aggregation, as well as quantify platelet function. Platelet aggregation increased with the increase of flow shear rate, while sample storage at room temperature for up to 5 h did not affect results of platelet function test. The intra-assay variability coefficient of variation of the MPFTP was <15%. The area under the curve of ROC showed that this platform had good diagnostic performance in the identification of platelet function inhibition by AS and 2-MeSAMP. CONCLUSION This MPFTP shows good analytical performance for the assay of platelet function and can be developed into a new clinical platelet function test device in the future.
Humans ; Platelet Function Tests

No abstract available.
Blood Platelets ; Humans ; Phenotype ; Platelet Function Tests

OBJECTIVE: To develop a new method for evaluating the inhibitory effect of aspirin on platelet by the three-dimensional (3D) morphological parameters. METHODS: The sodium citrate-anticoagulant peripheral blood samples collected from 12 healthy volunteers were divided into 2 groups: group treated with 200 μmol/L acetylsalicylic acid (ASA), and control group. The platelets in the 2 groups were washed and purified. The purified platelets were added into reaction pools modified with type I collagen and induced to activation and aggregation under static condition. The 3D morphology of the formed platelet aggregate was measured by the laser shape microscopic system. Meanwhile, the platelet function was detected by turbidometric light transmittance aggregometry (LTA). RESULTS: This technology could acquire the shape, height and 3D morphology of the platelet aggregates without label, and could quantify their volume parameters. ASA treatment could obviously change the morphology of platelet aggregates. Compared with the parameters of control group, the volume of platelet aggregates in experimental group decreased significantly (t=8.97, P<0.01), while the cross-sectional area showed no significant change (t=1.94, P>0.05). The receiver-operating characteristic curve(ROC) analysis showed that the platelet aggregate volume as a parameter to identify the ASA inhibition effect had 91.7% sensitivity and 75% specificity when the cut-off value equal to 1395 μm, and its accuracy and sensitivity were both better than those of platelet aggregates rate measured by LTA method. CONCLUSION The new method developed for evaluating the ASA inhibition of platelet aggregation may provide a complementary strategy for researching and clinically evaluating of ASA anti-platelet aggregation in future.
Aspirin ; Blood Platelets ; Hemostasis ; Humans ; Platelet Aggregation ; Platelet Function Tests

OBJECTIVE: To analyze and compare the correlation of platelet aggregation rate measured by platelet analyzer, platelet aggregometer and thromboelastography. METHODS: The performance of platelet analyzer in platelet count and platelet aggregation function was evaluated. The platelet aggregation rate of 55 patients with type 2 diabetes mellitus (T2DM) before and after taking aspirin alone (32 cases) and clopidogrel alone (23 cases) was measured by thromboelastography, platelet aggregometer and platelet analyzer respectively, and the analytical results were compared. The correlation between the results measured by different instruments and equipment were further analyzed and the data were included in the statistical analysis. RESULTS: The precision of platelet analyzer in day and in batch was 1/3 lower than the total error (7%). The contamination rate was 0.30%. The slope of regression equation was 1.02 and R was 0.99 in the linear range of 4.15×10/L to 1379.95×10/L. The coincidence rate of platelet count and platelet reference method was 85%, which met the requirements of industry standards. The platelet aggregation rates of patients with T2DM after clopidogrel or aspirin by using thromboelastography, platelet aggregometer and platelet analyzer respectively was significantly lower than those whom before clopidogrel administration (P<0.01). CONCLUSION Platelet analyzer can provide reliable, objective and accurate information for clinical detection of platelet count and aggregation function, which is meet the requirements of industry standards, and its results are similar to those of platelet aggregometer and thromboelastography.
Diabetes Mellitus, Type 2 ; Humans ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; Platelet Function Tests ; Thrombelastography

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

BACKGROUND: There are many causes for the failure of aspirin therapy in patients with acute ischemic stroke. Laboratory aspirin resistance (AR) might be involved in clinical aspirin non-response. The PFA-100 is a laboratory method to evaluate AR in the clinical setting. However, there has been limited data regarding concordance with optical platelet aggregometry, which is considered the gold standard for detecting AR. We retrospectively analyzed platelet function tests using the PFA-100 and an optical platelet aggregometer in 86 patients with acute ischemic stroke. METHODS: Eighty six patients were enrolled in the study and were evaluated the platelet function test by optical aggregometer and a PFA-100. We determined the variability in the prevalence of AR and the kappa value between the two tests in patients with acute ischemic stroke. RESULTS: Among 86 patients, 27 (31.4%) were detected as AR by the optical aggregometer and 31 (36.0%) by the PFA-100. There were 13 cases of AR (15.1%) in both laboratory methods. The optical platelet aggregometer results showed that female gender (P=0.03), aspirin monotherapy (P =0.05), and NIHSS at baseline (P=0.04) were related with AR in acute ischemic stroke. Multiple logistic regression analysis showed that NIHSS was independently associated with AR of the optical platelet aggregometer (OR=1.12 95%, CI: 1.00-1.25, P=0.05). CONCLUSION: The prevalence of AR was similar between the PFA-100 and the optical platelet aggregometer in patients with acute ischemic stroke. However, the concordance rate of these two tools is low.
Aspirin ; Blood Platelets ; Female ; Humans ; Logistic Models ; Platelet Aggregation ; Platelet Function Tests ; Prevalence ; Retrospective Studies ; Stroke

BACKGROUND: The purpose of this study is to investigate the prevalence of impaired platelet responsiveness to epinephrine in healthy subjects. Also, we compared the platelet aggregability in response to various agonists in normal population. METHODS: A total of 156 healthy subjects aged 21 to 57 years were investigated for the evidence of impaired responsiveness to epinephrine. Aggregometer PACKS-4 (Platelet Aggregation Chromogenic Kinetic System-4, Helena, Beaumont, USA) was used for platelet function test. Aggregating agonists (Helena Haemostasis Systems, UK) used in the study were consisted of ADP (10 micrometer), collagen (10 microgram/mL), epinephrine (300 micrometer) and ristocetin (1500 microgram/mL). Population showing platelet aggregability with more than 60% activity was classified as normal group, while aggregability with less than 20% as impaired responsiveness. RESULTS: Of 156 healthy subjects, 20.5% (32/156) showed impaired responsiveness, while 33.9% (53/156) revealed decreased aggregability with the activity of less than 60% to epinephrine. The mean of maximal percent aggregating activity for collagen was 90.5+/-11.4% and that of epinephrine was 66.5+/-34.4%. The mean aggregation activity (84.4+/-11.8%) for ADP in subjects showing normal response to epinephrine was significantly higher, compared with that (65.7+/-16.2%) of impaired responsiveness group to epinephrine (P<0.01). CONCLUSION: Impaired responsiveness to epinephrine, which is observed in healthy subjects, appears to be a kind of normal variant reaction. And this abnormality is not considered to be associated with any evident bleeding disorders.
Adenosine Diphosphate ; Blood Platelets* ; Collagen ; Epinephrine* ; Hemorrhage ; Platelet Aggregation ; Platelet Function Tests ; Prevalence* ; Ristocetin

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

Platelets play pivotal roles in hemostasis as well as pathological arterial thrombosis. The combination of aspirin and a P2Y₁₂ inhibitor has become the mainstay therapy in the ageing population with cardiovascular conditions, particularly during and after percutaneous coronary intervention. A number of novel P2Y₁₂ inhibitors has become available in the recent years, and they markedly vary in pharmacokinetic and pharmacodynamic properties. Perioperative physicians today face a challenge of preventing hemorrhage due to platelet inhibitors, while minimizing thrombotic risks. There are several point-of-care platelet function tests available in the peri-procedural assessment of residual platelet aggregation. However, these platelet function tests are not standardized in terms of sample processing, agonist type and potency as well as methods of detecting platelet activity. Understanding the differences in pharmacological properties of antiplatelet agents, principles of platelet function tests, and pertinent hemostatic strategies may be useful to anesthesiologists and intensivists who manage perioperative issues associated with antiplatelet agents. The objectives of this review are: 1) to discuss clinical data on aspirin and P2Y12 inhibitors relating to perioperative bleeding, 2) to outline different features of point-of-care platelet function tests, and 3) to discuss therapeutic options for the prevention and treatment of bleeding associated with antiplatelet agents.
Aspirin* ; Blood Platelets ; Hemorrhage ; Hemostasis ; Percutaneous Coronary Intervention ; Platelet Aggregation ; Platelet Aggregation Inhibitors* ; Platelet Function Tests ; Point-of-Care Systems ; Thrombosis

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