Degree Of Platelet Activation Research Articles

Impact of rise and fall phases of shear on platelet activation and aggregation using microfluidics.

Blood flow disorders are often the result of the non-physiological narrowing of blood arteries caused by atherosclerosis and thrombus. The blood then proceeds through rising-peak-decreasing phases as it passes through the narrow area. Although abnormally high shear is known to activate platelets, the shear process that platelets undergo in small arteries is complex. Thus, understanding how each shear phase affects platelet activation can be used to improve antiplatelet therapy and decrease the risk of side effects like bleeding. Blood samples were sheared (68.8 ms,5200s-1) in vitro by the microfluidic technique, and platelet activation levels (P-selectin and integrin αIIbβ3) and von Willebrand factor (vWF) binding to platelets were analyzed by flow cytometry. Post-stenosis platelet aggregation was dynamically detected using microfluidic technology. We studied TXA2, P2Y12-ADP, and integrin αIIbβ3-fibrinogen receptor pathways by adding antiplatelet drugs, such as acetylsalicylic acid (ASA, an active ingredient of aspirin that inhibits platelet metabolism), ticagrelor (hinders platelet activation), and tirofiban (blocks integrin αIIbβ3 receptor) in vitro, respectively, to determine platelet activation function mediated by transient non-physiological high shear rates. We demonstrated that platelets can be activated under transient pathological high shear rates. The shear rise and fall phases influenced shear-induced platelet activation by regulating the binding of vWF to platelets. The degree of platelet activation and aggregation increased with multiple shear rise and fall phases. ASA did not inhibit shear-mediated platelet activation, but ticagrelor and tirofiban effectively inhibited shear-mediated platelet activation. Our data demonstrated that the shear rise and fall phases play an important role in shear-mediated platelet activation and promote platelet activation and aggregation in a vWF-dependent manner. Blocking integrin αIIbβ3 receptor and hindering P2Y12-ADP were beneficial to reducing shear-mediated platelet activation.

Platelet activation and blood extracellular vesicles: The influence of venepuncture and short blood storage

Extracellular vesicles (EVs) as membrane-bound particles released by various cells are potential tools for diagnosis and treatment. Blood cells, particularly platelets, are the source of circulating EVs. MaterialEVs were enriched with gradient ultracentrifugation and measured by nanoparticle tracking assay. A flow cytometric multiplex assay was used for cellular source determination. Activation of platelets was measured as a percentage of CD62p+/CD61+ platelets and correlated with the concentration and size of released EVs. ResultsIn general there was no statistically significant correlation between EVs` concentration and degree of platelet activation. EVs from different cellular sources were detected. Comparing different needle thicknesses, there was a decrease in the EVs concentration for the 16G needle versus the 21G needle, but no difference was observed for EVs` size and phenotype or platelets activation. During blood storage, platelet activation increased, but there was no effect on the EVs` concentration, size, or phenotype. ConclusionsPreanalytical factors like needle thickness and storage time can affect the MVs' properties. Activation of platelets during blood collection or blood storage occurs; however, it is difficult to determine its effect on the physiological properties of EVs since the mechanisms of EVs` biogenesis and especially clearness are not precisely known.

Preparation of aminated poly (L‐lactic acid) film coated with multilayers of mussel‐inspired heparin‐like carboxymethylcellulose sodium and chitosan for anticoagulant materials

AbstractIn this study, dopamine hydrochloride was grafted onto the sulfated carboxymethylcellulose sodium with different sulfated degree (DA‐g‐SCMCS) as heparin‐like polysaccharides. By studying the preliminary structure and coagulation time of DA‐g‐SCMCS, the DA‐g‐SCMC2 possessing good anticoagulant properties were selected to be assembled layer by layer on the surface of aminated poly (L‐lactic acid) (APLLA) film with chitosan (CS). The characterization properties including morphologies and wettability of DA‐g‐SCMC2/CS multilayers modified APLLA films were studied by scanning electron microscope and water contact angle instrument. Anticoagulation tests revealed that the (DA‐g‐SCMC2/CS)15 multilayers modified APLLA film experienced a decrease of 37.5% and 73.68% in the adsorption of bovine serum albumin (BSA) and fibrinogen (FBG), respectively. And the platelet adhesion ability was reduced by 92.42% compared with the APLLA film. The degree of platelet activation (PF4 and TAT) and hemolysis rates of modified APLLA films also decreased significantly. Besides, the modified APLLA films promoted the growth of L929 cells and exhibited remarkable anti‐inflammatory and antibacterial abilities. To summarize, the APLLA films modified with heparin‐like multifunctional DA‐g‐SCMC2/CS multilayers exhibit outstanding biocompatibility, cytocompatibility, anti‐inflammatory, and antibacterial characteristics, showcasing their potential as anticoagulation materials.

In vitro study on the effect of fibrinogen γ-chain peptide-coated ADP-encapsulated liposomes on postcardiopulmonary bypass coagulopathy using patient blood

BackgroundFibrinogen γ-chain peptide-coated, adenosine 5'-diphosphate (ADP)-encapsulated liposomes (H12-ADP-liposomes) are potent hemostatic adjuvants that promote platelet thrombi formation at bleeding sites. Although we have reported the efficacy of these liposomes in a rabbit model of cardiopulmonary bypass coagulopathy, we are yet to address the possibility of their hypercoagulative potential, especially in human beings. ObjectivesConsidering its future clinical applications, we herein investigated the safety of using H12-ADP-liposomes in vitro using blood samples from patients who had received platelet transfusion after cardiopulmonary bypass surgeries. MethodsTen patients receiving platelet transfusions after cardiopulmonary bypass surgery were enrolled. Blood samples were collected at the following 3 points: at the time of incision, at the end of the cardiopulmonary bypass, and immediately after platelet transfusion. After incubating the samples with H12-ADP-liposomes or phosphate-buffered saline (PBS, as a control), blood coagulation, platelet activation, and platelet-leukocyte aggregate formation were evaluated. ResultsPatients’ blood incubated with H12-ADP-liposomes did not differ from that incubated with PBS in coagulation ability, degree of platelet activation, and platelet-leukocyte aggregation at any of the time points. ConclusionH12-ADP-liposomes did not cause abnormal coagulation, platelet activation, or platelet-leukocyte aggregation in the blood of patients who received platelet transfusion after a cardiopulmonary bypass. These results suggest that H12-ADP-liposomes could likely be safely used in these patients, providing hemostasis at the bleeding sites without causing considerable adverse reactions. Future studies are needed to ensure robust safety in human beings.

Computational Analysis of Flow Structures in Turbulent Ventricular Blood Flow Associated With Mitral Valve Intervention.

Cardiac disease and clinical intervention may both lead to an increased risk for thrombosis events due to a modified blood flow in the heart, and thereby a change in the mechanical stimuli of blood cells passing through the chambers of the heart. Specifically, the degree of platelet activation is influenced by the level and type of mechanical stresses in the blood flow. In this article we analyze the blood flow in the left ventricle of the heart through a computational model constructed from patient-specific data. The blood flow in the ventricle is modelled by the Navier-Stokes equations, and the flow through the mitral valve by a parameterized model which represents the projected opening of the valve. A finite element method is used to solve the equations, from which a simulation of the velocity and pressure of the blood flow is constructed. The intraventricular blood flow is complex, in particular in diastole when the inflow jet from the atrium breaks down into turbulent flow on a range of scales. A triple decomposition of the velocity gradient tensor is then used to distinguish between rigid body rotational flow, irrotational straining flow, and shear flow. The triple decomposition enables the separation of three fundamentally different flow structures, that each generates a distinct type of mechanical stimulus on the blood cells in the flow. We compare the results in a simulation where a mitral valve clip intervention is modelled, which leads to a significant modification of the intraventricular flow. Further, we perform a sensitivity study of the results with respect to the positioning of the clip. It was found that the shear in the simulation cases treated with clips increased more compared to the untreated case than the rotation and strain did. A decrease in valve opening area of 64% in one of the cases led to a 90% increase in rotation and strain, but a 150% increase in shear. The computational analysis opens up for improvements in models of shear-induced platelet activation, by offering an algorithm to distinguish shear from other modalities in intraventricular blood flow.

Assessment of apheresis platelets during 5 days of storage: A National Cancer Institute, Cairo University experience

BackgroundPlatelet transfusion therapy is widely used to prevent hemorrhage in patients with thrombocytopenia and platelet disorders. The platelet concentrate (PC) quality is affected by increased storage time, as reflected in the decreased number of platelets, morphological changes, and impaired functions. This study aimed to analyze the impact of 5 days storage on platelets count and the expression of CD63, and Annexin V as activation markers during PC storage. MethodsFifty PCs collected from single donors were tested for platelet count on days 0, 3, and 5 using a Sysmex blood counter. CD61, CD63, and Annexin V expression was analyzed by a multicolor Navios flow cytometer. ResultsThere was a significant decrease in platelet count during 5 days of storage. There was a direct relationship between storage time and degree of platelet activation. CD63 had almost double increased expression on day 5 than day 3. Annexin V showed significantly increased expression on day 3 with minor differences between days 3 and 5. ConclusionAccording to standard blood bank conditions, PC stored for 5 days showed a degree of in vitro activation as evidenced by CD63 and Annexin V expression, may lead to reduced therapeutic efficacy. Flow cytometry monitoring platelet activation in PC offers a better understanding of the changes during PC storage and may help improve platelet products.

Evaluation of Plateletcrit and Platelet Distribution Width in Patients with Non-Alcoholic Fatty Liver Disease: A Retrospective Chart Review Study.

BackgroundPlatelets are considered to be essential in proinflammatory environments, including atherosclerosis. The degree of platelet activation has been demonstrated to be correlated with plateletcrit and platelet distribution width. The main purpose of this study was to assess the relationship between plateletcrit (PCT), platelet distribution, and the degree of hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD).Material/MethodsWe enrolled 225 biopsy-proven NAFLD patients and 142 control subjects without NAFLD. NAFLD patients were separated into 2 groups according to percentage of steatosis. Demographic and clinical data were collected retrospectively.ResultsPCT level was significantly higher in NAFLD group I and group II than in the control group. PCT was higher in the NAFLD groups than in the control group. However, there was no difference according to PCT and PDW levels between NAFLD groups.ConclusionsIn this study, a relationship was found between PCT and hepatosteatosis, but no relationship was found with PDW. PCT might be a useful biomarker for early detection of steatohepatitis in patients with nan-alcoholic fatty liver disease.

Evaluating platelet activation related to the degradation of biomaterials using molecular markers

The effective assessment of platelet activation is an important component of the evaluation of cardiovascular implants. Currently, most evaluation is performed based on the ISO 10993-4 international standard. However, the methods specified in this standard were originally designed for non-degradable materials, and the applicability of these methods to evaluate degradable materials has not been carefully assessed. Here, the platelet activation response was evaluated (using blood from health rabbits) for three typical degradable materials (collagen, polylactic acid, and hydroxyapatite) by measuring the widely used molecular markers CD62 P, CD63, and CD40 L and the three molecular markers PF4, β-TG, and TXB2 that are referenced in the ISO 10993-4 standard. The variations of these six markers were compared in the simulated degradation of the three test materials. The results showed differences in platelet activation with degradation that were strongly related to the surface physicochemical properties. Changes in the surface roughness and contact angle of the materials correlated with changes in the degree of platelet activation. The six tested platelet activation molecular markers show promise for assessment of platelet function in degradable medical devices, providing guidance for quality control strategies and the design and improvement of safe medical devices.

Evaluating the Platelet Activation Related to the Degradation of Biomaterials by Scheme of Molecular Markers

The evaluation of platelet activation of medical devices using in cardiovascular system is very meaningful. Currently, it is mainly based on the ISO10993-4 international standard. However, the methods given in the standard are originally designed for non-degradable materials, the applicability, the operability, and the convenience to degradable materials of the methods needs to be carefully studied. In this study, the platelet activation by 3 typical degradable materials (collagen, polylactic acid and hydroxyapatite) were evaluated by three widely used molecular markers CD62P, CD63, CD40L and the three molecular markers PF4, β-TG and TXB2 mentioned in the ISO10993-4 standard. The variations of the six markers in a simulated degradation process of the degradable materials were compared. It was found that the degree of platelet activation changed with the degradation and was strongly relative with the surface physicochemical properties. For example, when the surface roughness and contact angle of the materials change, the degree of platelet activation also changes. These six platelet activation molecular markers can to be the promising key for the assessing of platelet function in degradable medical devices which is instructive for the quality control and the development of new degradable medical devices.

Expression of platelet miR-223 in coronary artery disease patients and its clinical significance

Objective: To investigate the correlation of the expression of platelet microRNA-223 (miR-223) with the degree of platelet activation and the severity of coronary lesions in patients with coronary artery disease (CAD). Methods: A total of 204 consecutive patients underwent coronary artery angiography (CAG) at Beijing Anzhen Hospital between April and December 2016 were enrolled. According to CAG results, all the patients were divided into two groups: 112 patients in CAD group and 92 patients in control group. Real-time fluorescent quantitative PCR was used to detect the expression level of platelet miR-223 and mRNA of its target gene P2Y12. Flow cytometry was performed to detect the expression of platelet associated complement-1 (PAC-1). Results: Compared with control group, the expression level of platelet miR-223 in CAD group was higher [(1.27 (1.17, 1.32) vs 0.73 (0.64, 0.79), P<0.001], while the expression level of P2Y12 mRNA was lower [0.75 (0.51, 0.96) vs 1.00 (0.80, 1.64), P<0.001]. The positive expression rate of PAC-1 of CAD group was higher than that of control group (P<0.001). The expression level of platelet miR-223 was negatively correlated with the expression of P2Y12 (r=-0.39, P=0.02), but positively correlated with the expression of PAC-1 (r=0.50, P<0.001). The platelet miR-223 expression level had a positive correlation with the Gensini score in CAD group (r=0.90, P<0.001), but had no significant correlation with platelet aggregation (r=-0.06, P=0.36). Conclusion: The expression level of platelet miR-223 in patients with CAD may be an indicator for monitoring platelet activation and assessing the severity of CAD.

The Effect of Probiotic Lactic Acid Bacteria (LAB) Strains on the Platelet Activation: A Flow Cytometry-Based Study

Platelet-activation and agonist-induced platelet aggregation process to the pathogenesis of Infective Endocarditis (IE), bacteremia symptoms or other thrombotic complications and cardiovascular diseases. Activation of platelets by probiotic lactic acid bacteria strains is considered as thrombotic initiative factor contributing to the development and progression of Lactobacillus endocarditis. The main purpose of the current study was to evaluate the immunologic enhancement effect of probiotic strains L. plantarum, L. acidophilus and L. rhamnosus on the activation of blood platelets. Whole fresh blood flow cytometry was used to measure p-selectin expression and fibrinogen binding at basal levels and following stimulation with platelet agonists and probiotic lactic acid bacteria strains. Platelet activation was determined by labelling with FITC-conjugated anti-human fibrinogen and phycoerythrin (PE)- conjugated anti-human CD62p before analysis by flow cytometry. Thrombin Receptor Activator Peptide-6 (TRAP-6) was used as positive control. The percentage of CD62p-positive platelets, FITC-conjugated and the light scatter profiles of the agonist-activated platelets were used to identify the occurrence and degree of platelet activation. Probiotic lactic acid bacteria strains included in this study did not show any effect on spontaneous activation of human blood platelets. These test strains also failed to exacerbate or diminish the platelet activation property when co-incubated with TRAP-6 platelet agonist. Hence, this is the first in vitro report showing the safety of a group of probiotic lactic acid bacteria in terms of their potential to contribute to the pathogenesis of infective endocarditic (IE), bacteremia symptoms or other thrombotic disorders and correlated cardiovascular complications by initiating the platelet activation.

Autologous platelet-rich plasma: evidence for clinical use.

Autologous platelet-rich plasma (aPRP) is growing in popularity as a therapy to augment wound healing, speed the recovery from muscle and joint injuries, and enhance recovery after surgical repair. High-profile athletes treated with aPRP have increased the demand from the general population. Yet, evidence to support the use of aPRP in most clinical settings is weak, because of poorly controlled clinical trials. Preparations of aPRP vary by platelet count, leukocyte content, and degree of platelet activation. Nonetheless, these heterogeneous preparations are used in trials to assess the efficacy of aPRP treatment. Despite weak evidence, the use of aPRP continues to grow. High-quality randomized controlled trials are needed to validate or repudiate the potential efficacy of aPRP. Standards for aPRP preparation and quality should be created.

Peculiarities of Platelet Activation Changes in Patients with Chronic Schizophrenia, Depending on the Severity of Positive and Negative Symptoms during the Remission Formation

The aim of our study was to compare the changes in the severity of positive, negative and psychopathological PANSS symptoms which occur at an outcome of an attack in schizophrenic patients along with remission formation and the degree of platelet activation in these patients. Psychometric scale of the Positive and Negative Syndrome Scale (PA NSS) and the method of estimation of platelet activation based on the calculation of cells number after elution from the column with sepharose CL-2B were used. The changes in the severity of the disease were estimated using the PANSS scale of chronic schizophrenic patients in remission formation. An increase in platelet activation was determined on the basis of the above described quantitative parameter. Comparison of changes in platelet activation parameter with changes in the disease severity rating detected similar statistically indistinguishable (p > 0.05) changes in the severity of positive symptoms and quantitative variable of platelet activation between the 1st and the 3rd visits in the period of remission formation. Platelet number after elution from the column during the 3rd visit was approximately two times less than during the 1st visit (p < 0.002). PANSS positive subscale shows a decrease of the severity of the syndrome by 1.6 times (p < 0.0002). In addition the difference between the platelet activation parameter and severity of the negative syndrome was fixed during the 3rd visit (p < 0.034). Similar changes in the severity of positive syndrome and platelet activation parameter were presented from 1st to 3rd visit in the remission formation. A distinction between the platelet activation parameter and severity of the negative syndrome was fixed during the 3rd visit.

Platelet activation and arterial peripheral serotonin turnover in cardiac remodeling associated to aortic stenosis

Peripheral serotonin (5-HT) has been involved in adverse cardiac remodeling and valve fibrosis. The peripheral levels of 5-HT mainly depend on its release from activated platelets and degradation by monoamine oxidase A (MAO-A). The SERAOPI study investigated the relationship between arterial serotoninergic system, degree of platelet activation and cardiac remodeling, in patients with aortic valve stenosis (AS). Thirty patients with severe AS and 15 control subjects underwent transthoracic echocardiography, radial, and aortic arterial blood sampling. Measurements of 5-HT and its MAO-A-dependent degradation product, 5-HIAA, were performed by HPLC. Arterial platelet activation was assessed by flow cytometry analysis of platelet surface expression of P-selectin and activated integrin GPIIb/IIIa. Activated platelets and arterial plasma 5-HT increased in AS patients as compared to control subjects (P-selectin 1.08 ± 0.2MFI vs. 0.49 ± 0.1MFI, P = 0.04; GPIIb/IIIa 0.71 ± 0.1MFI vs. 0.35 ± 0.1MFI; P = 0.0015 and arterial plasma 5-HT 11.55 ± 1.6 nM vs. 6.18 ± 0.7 nM, P = 0.028, respectively). Moreover, 5-HT was strongly correlated to left ventricular hypertrophy assessed by echocardiography. The correlation was independent of cardiovascular risk comorbidities and others echocardiographic AS parameters. Finally, plasma 5-HIAA increased in AS patients (74.64 ± 9.7 nM vs. 37.16 ± 4.1 nM; P = 0.0002) indicating a higher 5-HT degradation rate by MAO-A. Platelet activation, arterial circulating serotonin, and serotonin degradation increased in patients with AS. These observations suggest that the serotoninergic system may contribute to the pathogenesis of AS including valve fibrosis and adverse ventricular remodeling.

Clinical Features of Heparin-Induced Thrombocytopenia Diagnosed By Lumi-Aggregometry

Background: Heparin-induced thrombocytopenia (HIT) is associated with anti-platelet factor-4 (PF4)/heparin antibodies that activate platelets, resulting in thrombocytopenia and a pro-thrombotic state. At our institution antibody-mediated platelet activation is demonstrated by lumi-aggregometry, which is a method previously validated against the gold standard serotonin-release assay (SRA). Lumi-aggregometry does not involve radioactive isotopes, which is its major advantage over the SRA. The clinical course of HIT diagnosed via SRA and ELISA has been previously described, and clinical prediction tools such as the 4-T score were validated using these diagnostic tests. However, the clinical picture of HIT diagnosed by lumi-aggregometry has not been previously described.Aims: The objective of this study is to describe the clinical and laboratory presentation of patients diagnosed with HIT by lumi-aggregometry.Methods: Patients with clinically suspected HIT and quantitative anti-PF4 IgG-specific ELISA OD ≥0.400 (Gen-Probe, San Diego) received confirmatory HIT testing by lumi-aggregometry. Briefly, HIT antibody-induced activation of washed healthy donor platelets was tested at therapeutic (0.1U/mL and 0.5U/mL) and high (100U/mL) porcine heparin concentration. The degree of platelet activation was quantitated luminographically based on the light flash reaction of ATP (released from platelet dense-granules) with luciferin luciferase reagent. A ratio of therapeutic to high heparin luminescence amplitude of >5.0 and platelet aggregation at therapeutic, but not high, concentrations was considered a positive result. The results of assays performed by our regional HIT testing referral laboratory from June 2009 to July 2012 were reviewed to identify patients with positive HIT testing by lumi-aggregometry. Patient records were retrospectively reviewed to obtain predefined data on baseline patient characteristics, heparin exposure, platelet counts, and thrombotic events occurring in the 5 days preceding or the 30 days following the date of positive HIT testing.Results: We identified 43 patients diagnosed with HIT by lumi-aggregometry (median age 68.0, 49% male) while under the care of local academic (46%) or urban community hospitals (37.2% medical; 53.5% surgical; 9.3% intensive care). Median baseline platelet count was 187 (14-349). Median date of platelet drop post-heparin exposure was 6 days (range 3-14) in patients without prior heparin exposure or platelet transfusions (Figure 1). Platelet drop >50% and platelet nadir ≥20x109/L were present in the majority of patients (Table 1). Thrombocytopenia occurred prior to (70.5%) or the same day (23.5%) as thrombosis in 16/17 patients with serial platelet counts who developed HIT-associated thromboembolism.Conclusion: Patients diagnosed with HIT by lumi-aggregometry present with similar findings to those described in SRA-confirmed HIT. These findings lend support to the use of lumi-aggregometry as an accurate diagnostic assay for the clinico-pathologic syndrome of HIT. [Display omitted] Table 1Percentage platelet drop from baseline and platelet nadirPercent platelet dropPlatelet nadir>50%30-50%<30%≥20 x 109/L283210-19 x 109/L510<10 x 109/L110 DisclosuresSzkotak:Alexion Pharmaceuticals: Research Funding. Sandhu:Celgene: Honoraria; Jansen: Honoraria; Novartis: Honoraria.

The relationship between platelet indices and clinical features of coronary artery disease

Platelets play a key role in the development and progression of cardiovascular disease. The degree of platelet activation may be assessed by platelet indices such as platelet count, mean platelet volume (MPV) and platelet distribution width (PDW). To evaluate the relationship between platelet indices and clinical features of coronary artery disease (CAD). Our population is represented by a total of 441 consecutive patients undergoing coronary angiography. Patients were divided into three groups according to their clinical presentation: Patients with stable angina (Group I), with acute coronary syndrome (Group II), and with a normal coronary angiogram (Group III). All demographic and clinical features were collected retrospectively. Platelet indices were measured in all patients. There was no statistical difference for platelet count, MPV and PDW values among the groups. Correlation analysis showed a positive association between platelet count and Gensini scoring (Kendall's tau b, r = 0.312, p = 0.037, two-tailed)and also age (Kendall's tau b, r = 0.518, p = 0.001, two-tailed) in patients with CAD. However, there was no significant correlation between Gensini scoring and MPV or PDW values in these patients. PDW and MPV may not be related to the clinical features or presentation and extent of CAD. Our study findings add to the conflicting results of previous studies in this area. Prospective trials with longer follow-up periods and larger samples are warranted to conclusively define the role of platelet indices in CAD.

Evaluation of therapeutic efficacy on combined use of clopidogrel and ozagrel sodium in the treatment of acute ischemic stroke

Background Antiplatelet aggregation treatment has become a regular treatment of ischemic stroke. The affirmation of antiplatelet therapy is mainly derived from patients with clinical use, which can not provide the laboratory indexes for evaluation of a recognized accuracy. Studies have confirmed that the degree of platelet activation is associated with atherosclerosis and ischemic stroke, and recognized that both CD62p (α-platelet granule membrane glycoprotein) and CD63 (lysosomal membrane glycoprotein) were important indexes of platelet activation. This study aims to explore the differences of efficacy between combined use of clopidogrel and ozagrel sodium and monotherapy by aspirin in the treatment of acute ischemic stroke by investigating the expression of CD62p and CD63. Methods Flow cytometry was employed to detect CD62p and CD63 expression on circulating platelet in patients with ischemic stroke and normal control group. The positive rate of CD62p and CD63 was detected in patients with ischemic stroke who were treated with aspirin 0.15 g (single drug therapy) and clopidogrel 75 mg + ozagrel sodium 80 mg (combination therapy) before and after one and two weeks' treatment. National Institute of Health Stroke Scale (NIHSS) scores were measured in patients with ischemic stroke at the same time in three periods respectively to evaluate the improvement of neural function. Results Platelet CD62p and CD63 positive expression rate in ischemic stroke group were higher than normal control group before treatment (P = 0.001, 0.032). CD62p and CD63 positive expression rate and NIHSS score were measured at different times, and the differences were statistically significant (F = 56.693, P = 0.000; F = 21.544, P = 0.000; F = 216.271, P = 0.000, respectively). Compared with before treatment, CD62p and CD63 positive expression rate and NIHSS score decreased significantly after treatment (P = 0.000, for all), but the differences between aspirin group and combination group were not statistically significant (P > 0.05, for all). There was no interaction between the treatment groups and measuring time with CD62p and CD63 positive expression rate (F = 1.403, P = 0.250; F = 2.830, P = 0.063), while there was interaction between treatment groups and measuring time with NIHSS score (F = 4.518, P = 0.013). Conclusion Antiplatelet drug treatment of acute ischemic stroke is effective. The curative effect of combined treatment (clopidogrel and ozagrel sodium) is not superior to aspirin alone. CD62p positive expression rate in acute stage of ischemic stroke can measure the effect of antiplatelet therapy, while the determination of CD63 needs further research.

Effect of losartan on the ultrastructural morphology of blood cells in patients with diabetes mellitus and hypertension

U ltrastructural changes of blood cells in with patients with hypertension of 1-2-degree, in patients with diabetes mellitus type 2 at compensation and subcompensation phase as well as in patients with diabetes mellitus and hypertension during correction of blood pressure with losartan was d efined. It is shown that in patients with hypertension of 1-2-degree relative content of activated platelets does not differ from the normal level. In patients with diabetes mellitus type 2 at compensation or subcompensation phase increase of degree of platelet activation, regardless of presence (150.9%) or absence of hypertension (141.5%) is observed . Conducted antihyper ­ tensive therapy does not affect the spontaneous activation of platelets within 1 year. In patients with hypertension potential aggregation of platelets is the most sensitive element of platelet hemostasis damage, which can be normalized beginning with 6 - th month of losartan treatment. In patients with diabetes mellitus type 2 with hypertension elevation of platelet aggregation is the most significant (75.4%) and a reliable effect of antihypertensive therapy on limitation of platelet aggregation is achieved in 9 months of treatment. The degree of platelet degranulation is not different from the norm in patients with hypertension and significantly elevated in patients with diabetes mellitus type 2 (by 81.0%), during 1-year observation a constant level of the parameter is revealed . In the group of patients with diabetes mellitus and hypertension, where the original content of degranulated platelets is sharply increased (by 76.2%), a significant positive d y namic s in the course of treatment with losartan is observed .

Binding of Oxidized Low-Density Lipoprotein on Circulating Platelets Is increased in Patients With Acute Coronary Syndromes and Induces Platelet Adhesion to Vascular Wall In Vivo—Brief Report

Hyperlipidemia is associated with platelet hyperactivity. In the present study, we evaluated the binding of oxidized low-density lipoprotein (oxLDL) on the surface of circulating platelets in patients with stable coronary artery disease and acute coronary syndromes and its possible association with platelet activation. Furthermore, the role of oxLDL binding on platelet adhesion to collagen and endothelial cells in vitro as well as after carotid ligation in mice was investigated. Using flow cytometry, patients with acute coronary syndromes (n=174) showed significantly enhanced oxLDL binding compared with patients with stable coronary artery disease (n=182; P=0.007). Platelet-bound oxLDL positively correlated with the degree of platelet activation (expression of P-selectin and activated fibrinogen receptor; P<0.001 for both). Plasma oxLDL was increased in patients with acute coronary syndromes compared with stable angina pectoris patients. Preincubation of isolated platelets with oxLDL, but not with native LDL, resulted in enhanced platelet adhesion to collagen and activated endothelial cells under high shear stress in vitro, as well as after carotid ligation in C57BL/6J mice and apolipoprotein E(-/-) mice fed a high cholesterol diet. Increased platelet-bound oxLDL in patients with acute coronary syndromes may play an important role in atherothrombosis, thus providing a potential future therapeutic target.

Rapid P2Y 12 Inhibition

Acute coronary syndrome (ACS) is still a serious condition associated with decreased quality of life, increased healthcare expenditures, and premature death. The prevalence of ACS is expected to increase with aging of the population and with the epidemics of obesity and diabetes. The short- and long-term mortality after an ACS has been dramatically reduced by the development of revascularization techniques and new antithrombotic agents. The past decade has seen many trials evaluating new oral and parenteral antiplatelet agents with greater potency than aspirin and clopidogrel. Several antiplatelet agents have been developed, with the ultimate goal to obtain optimal antiplatelet therapy for both the acute and the chronic phases of disease. Articles see p 336, 347 Ideally, efficiency requires several pharmacodynamic proprieties, such as a fast onset of action (immediate onset for emergency situations), a strong degree of platelet inhibition (at least stronger than the standard of care [aspirin and clopidogrel]), a narrow interindividual variability with no impact of genetic variants and no drug-to-drug interaction, and an easy administration (an oral drug for maintenance therapy and an intravenous formulation for rapid loading). Of course, this drug should also lead to a convincing reduction of recurrent ischemic events in an adequately powered phase 3 trial. With regard to safety, the illusion of having the same dose of a single antiplatelet drug to treat all clinical situations has passed. The degree of platelet activation and aggregation is different across clinical situations (eg, acute ST-segment–elevation myocardial infarction [STEMI] versus secondary prevention) and varies over time in the same patient. Recent large phase 3 trials have confirmed the importance of dosing and the target population treated with the new agents.1–4 From a safety standpoint, an ideal antiplatelet agent would also have an intravenous and oral formulation, with different doses tested in …