Beta-thromboglobulin Research Articles

Biomarkers of coagulation, endothelial, platelet function, and fibrinolysis in patients with COVID-19: a prospective study

Prospective and sequential evaluation of homeostatic changes leading to thrombosis across COVID 19 disease severity spectrum are limited. In this prospective observational study, haemostasis was evaluated in patients with mild, moderate-severe, and critical COVID-19 infection. Markers of endothelial activation [Soluble thrombomodulin (sTM), von Willebrand Factor (VWF)], platelet activation [Soluble P-selectin, beta-thromboglobulin (BTG)] and global haemostasis [Rotational thromboelastometry (ROTEM)] were evaluated on days 1 and 5 after admission. The study cohort comprised of 100 adult patients (mild = 20, moderate-severe = 22, critical = 58). Sixty-five patients received anticoagulation for 10 (7–14) days. Thrombotic events were seen in 9 patients. In-hospital mortality was 21%. Endothelial activation markers were elevated at baseline in all subgroups, with levels in moderate-severe (sTM = 4.92 ng/ml, VWF = 295 U/dl) [reference-ranges: sTM = 2.26–4.55 ng/ml; Soluble P-selectin = 13.5–31.5 ng/ml; BTG = 0.034–1.99 ng/ml] and critical patients (sTM = 6.07 ng/ml, VWF = 294 U/dl) being significantly higher than in the mild group (sTM = 4.18 ng/ml, VWF = 206 U/dl). In contrast, platelet activation markers were elevated only in critically ill patients at baseline (Soluble P-selectin = 37.3 ng/ml, BTG = 2.51 ng/ml). The critical group had significantly lower fibrinolysis on days 1 and 5 when compared with the moderate-severe arm. COVID-19 infection was associated with graded endothelial activation and lower fibrinolysis that correlated with illness severity.

Omega-3 Fatty Acids and Markers of Thrombosis in Patients with Atrial Fibrillation.

Omega-3 fatty acids (n-3 FAs) are associated with a lower risk of ischemic stroke in patients with atrial fibrillation (AF). Antithrombotic mechanisms may in part explain this observation. Therefore, we examined the association of n-3 FAs with D-dimer and beta-thromboglobulin (BTG), markers for activated coagulation and platelets, respectively. The n-3 FAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and alpha-linolenic acid (ALA) were determined via gas chromatography in the whole blood of 2373 patients with AF from the Swiss Atrial Fibrillation cohort study (ClinicalTrials.gov Identifier: NCT02105844). In a cross-sectional analysis, we examined the association of total n-3 FAs (EPA + DHA + DPA + ALA) and the association of individual fatty acids with D-dimer in patients with detectable D-dimer values (n = 1096) as well as with BTG (n = 2371) using multiple linear regression models adjusted for confounders. Median D-dimer and BTG levels were 0.340 ug/mL and 448 ng/mL, respectively. Higher total n-3 FAs correlated with lower D-dimer levels (coefficient 0.94, 95% confidence interval (Cl) 0.90-0.98, p = 0.004) and lower BTG levels (coefficient 0.97, Cl 0.95-0.99, p = 0.003). Likewise, the individual n-3 FAs EPA, DHA, DPA and ALA showed an inverse association with D-dimer. Higher levels of DHA, DPA and ALA correlated with lower BTG levels, whereas EPA showed a positive association with BTG. In patients with AF, higher levels of n-3 FAs were associated with lower levels of D-dimer and BTG, markers for activated coagulation and platelets, respectively. These findings suggest that n-3 FAs may exert antithrombotic properties in patients with AF.

Platelet functions in lymphatic filariasis patients

Filariasis is a chronic disease where parasitic worms survive in human hosts even for decades and lead to complications like lymphedema and elephantiasis. Despite the persistent existence of filarial parasites in human hosts, fatal and thrombotic complications are not known, unlike other parasitic diseases like malaria. This suggests that filarial parasites might be affecting the host's platelet functions. This study was conducted to examine platelet functions in confirmed filariasis patients and healthy controls. Results showed that filariasis patients had larger platelets, inhibited aggregation, and slower speed of aggregation, compared to controls. However, in vivo markers of platelet activation and degranulation (beta thromboglobulin and soluble P-selectin) were not affected. Observations suggested that there is increased platelet turnover, cellular apoptosis and inhibited platelet functions in filariasis patients compared to controls. Platelet function inhibition was not associated with the duration of disease, lymphedema-affected organs, or gender of patients. This study confirms that filarial parasites modulate platelet functions in human hosts.

The Role of Calcium in Augmenting the Efficacy of Primary Homeostasis after Hemorrhagic Shock

Background: Traumatic Hemorrhagic Shock (THS) causes hypocalcemia (Ca). This study assesses how low Ca affects platelet (Plt) function. Study Design: A research registry was queried for 555 studies on 341 patients (pts) with THS requiring 14.2 units RBC, 8.4 units FFP, 3.6 units Plt, and 18.9 mEq Ca by end of O.R. (7.3 hours). Factors analyzed included Plt count, Ca, Bleeding Time (BT), Plt aggregation with ADP (PAadp) and collagen (PAcol), including Max PA, T1/2 PA, and rate PA, plus platelet release factors, beta thromboglobulin (BTG) and Plt PF-4. Studies were made in O.R. (26 pts) during fluid uptake phase II at 29 hours (216 pts), during fluid mobilization phase III at 56 hours (283 pts), and as outpatients (30 pts). Results: THS caused low Plts (1x10 SD) in O.R (107 ± 43), in phase II (96 ± 35), and in phase III (105 ± 59) and low Ca in O.R. (1.6 ± 0.3), in phase II (1.8 ± 0.2), and in phase III (2.1 ± 0.2). Low Plt and Ca correlated (p=<0.05) with PAadp and PAcol in O.R., phase II, and phase III. Ca correlated directly with Plt count, aggregation, BTG and PF-4, and inversely with BT. All outpatient studies were normal. Conclusion: THS causes Ca which leads to low Plt and impaired function. Routine Ca supplementation is recommended for THS.

Depressive symptoms and inflammatory markers following acute myocardial infarction: A scoping review

• Acute myocardial infarction (AMI) and depression may share inflammatory markers. • Sustained, low-grade inflammation has been seen in post-AMI depression. • TNF- α , IL-6, and CRP show promise as indicators for depression following AMI. • Inflammatory markers signify possible therapeutic target for post-AMI depression. Among patients with recent acute myocardial infarction (AMI), there is an increased prevalence of depression which is associated with elevated morbidity, mortality, and rehospitalization. Yet, depression is frequently underdiagnosed and undertreated in patients following AMI. The paucity of data informing the management and treatment of depression in this population emphasizes the need for further investigation into the pathophysiological relationship between depression and AMI. Depressive symptoms following AMI may arise due to a range of factors, including the activation of the immune system. However, the specific role of inflammation in the etiology of both depression and AMI remains poorly understood. Therefore, the present review systematically identifies and critically evaluates the relevant inflammatory biomarkers of depression in the high-risk AMI population. Articles published between January 1 st , 2000, and December 31 st , 2020 in the PubMED, Cochrane, EMBASE, and Web of Science databases were assessed. A total of 30 documents were considered and found eligible for this review. The inflammatory biomarkers reviewed include tumor necrosis factor- α (TNF- α ), interleukin (IL)-1 β , IL-6, IL-8, IL-10, IL-17a, IL-18, IL-12p70, interferon- λ (IFN λ ), C-reactive protein (CRP), intracellular adhesion molecule-1 (ICAM-1), endothelin-1 (ET-1), platelet factor 4 (PF4), and beta-thromboglobulin (BTG). The studies reviewed suggest sustained, low-grade inflammation is an important component of depression following AMI. TNF- α , CRP, and IL-6 showed significant promise as reliable indicators for depression following AMI. Accordingly, it is postulated that inflammation is relevant in the pathogenesis of post-AMI depression. Further investigation of the inflammatory markers detected in patients with post-AMI depression will extend the pathophysiological understanding of this condition and potentially lead to the identification of novel therapeutic targets.

Differential Effects of Clopidogrel With or Without Aspirin on Platelet Reactivity and Coagulation Activation: A Randomized Trial in Healthy Volunteers

Dual antiplatelet therapy (DAPT) is standard in acute coronary syndrome but confers a bleeding risk. To compare effects of clopidogrel single antiplatelet therapy (SAPT) with clopidogrel-based DAPT on hemostatic system activation we conducted a randomized clinical trial in 44 volunteers (clopidogrel (d1: 600mg, d2-6: 150mg) ± aspirin (100mg)). Multiple electrode aggregometry-adenosine diphosphate (MEA-ADP) and MEA-arachidonic acid (MEA-AA) triggered aggregometry, vasodilator-stimulated phosphoprotein (VASP), beta thromboglobulin, p-selectin, thromboxane B2 , d-Dimer, prothrombin fragment 1.2 (f1.2), and a phospholipid-dependent clotting time were measured in venous blood. Changes are described by mean differences (Δmean (95% confidence interval (CI)) or geometric mean ratios (95% CI)). DAPT and SAPT comparably and significantly decreased MEA-ADP at 2hours (-60% vs. -63%; P=0.35, Δmean -4.9, 95% CI -15.4 to 5.5). At 24hours (-59% vs. -47%, P=0.04, Δmean -11.1, 95% CI -21.7 to -0.4]) and 8days (-61% vs. -53%, P=0.04, Δmean -11.3, 95% CI -22.0 to -0.6). Both treatments significantly reduced VASP and MEA-AA after 2hours and 8days. DAPT inhibited MEA-AA significantly stronger at 2hours (-77% vs. -30%; P<0.0001, Δmean -39.6, 95% CI -54.2 to -25.0), at 24hours (-80% vs. -27%, P<0.0001, Δmean -47.8, 95% CI -62.3 to -33.3), and 8days (-79% vs. -27%, P<0.0001, Δmean -48.9, 95% CI -62.5 to -35.4). Neither treatment significantly influenced beta thromboglobulin or p-selectin. DAPT abolished and SAPT reduced thromboxane B2 after 24hours and 8days. The d-Dimer was reduced by DAPT (0.94, 95% CI 0.89-1.00, P=0.04) at 2hours but not after 24hours and 8days. SAPT did not decrease d-Dimer. Neither treatment affected f1.2. DAPT and SAPT comparably affect platelet and coagulation activation in venous blood.

Association between hemostatic markers, serum lipid fractions and progression of cerebral small vessel disease: A 2-year follow-up study

IntroductionLittle is known if hemostatic markers and serum lipid fractions can predict further radiological progression beyond vascular risk factors in cerebral small vessel disease (SVD). We investigated whether they are associated with SVD radiological progression and if they are related to different SVD clinical manifestations. MethodsA single-center, prospective, cohort study with 2 years of radiological follow-up was performed in consecutive patients with different SVD manifestations. The study group consisted of 123 patients: 49 with lacunar stroke (LS), 48 with vascular dementia (VaD) and 26 with vascular parkinsonism (VaP). We assessed SVD progression by a visual SVD scale. We determined the relationship between serum or plasma concentrations of tissue factor (TF), thrombomodulin, beta-thromboglobulin (BTG), fibrinogen, D-dimer and total cholesterol, HDL-C, LDL-C, triglycerides and SVD progression by logistic regression analysis. Results34.9% patients had SVD radiological progression: 43% had isolated WMLs progression, 23.2% had new lacunes, 34.8% had both WMLs progression and new lacunes. Fibrinogen [OR 1.02 (95% CI 1.006–1.011] was significantly associated with risk of new lacunes or WMLs progression regardless of the clinical SVD manifestation. While low HDL [OR 0.96 (0.93–1)] and TF [OR 1.07 (0.99–1.1)] were marginally associated with new lacunes, BTG [OR 1.005 (0.99–1.01)] was associated with WMLs progression. ConclusionWe found a relationship between fibrinogen and risk of radiological progression of SVD regardless of the clinical SVD manifestation. In addition, lower HDL and increased TF predicted development of new lacunes, and higher BTG was associated with risk of WMLs progression.

The effect of Naoxintong capsule treatment on carotid artery intima-media thickness, serum beta thromboglobulin, P-selectin and plasminogen activator inhibitor-1 in elderly type 2 diabetic patients with subclinical atherosclerotic vascular disease

Objective To investigate the effects of Naoxintong Capsule treatment on the carotid artery intima-media thickness(IMT), plasma beta thromboglobulin(beta-TG), P-selectin(CD62p)and plasminogen activator inhibitor-1(PAI-1)in elderly patients with type 2 diabetes mellitus and subclinical atherosclerotic vascular disease. Methods In retrospective study, 110 cases of elderly patients with type 2 diabetic vascular diseases were selected and admitted as study subjects from June 2014 to May 2015.They were randomized into observation group and control group(n=55, each). All patients were given routine treatment.The patients in the observation group were treated with Naoxintong Capsule.The levels of plasma β-TG, CD62p and PAI-1 were measured and compared between two groups. Results Before treatment, there were no significant differences in IMT, PAI-1, β-TG and CD62p levels between the two groups(P>0.05). After treatment, the observation group versus control group showed an improved four parameters of carotid artery IMT(1.31 ±0.26)mm vs.(1.44 ±0.26)mm, PAI-1(2.23 ±0.48)μg/L vs.(2.56 ±0.61)μg/L, β-TG(29.76 ± 10.24)μg/L vs.(35.98 ± 10.35)μg/L, CD62p(162.3 ± 21.5)ng/L vs.(176.96 ± 20.3)ng/L(t=4.058, 3.965, 11.293, 14.624 respectively, all P<0.05)with statistically significant differences. Conclusions Naoxintong Capsule treatment of type 2 diabetic patients with subclinical atherosclerotic vascular disease can reduce carotid intima-media thickness, decrease platelet releasing activity and lower the oxidative stress reaction.Thereby, it protects the vascular endothelium, and alleviates subclinical atherosclerotic vascular disease in the elderly type 2 diabetic patients. Key words: Diabetes mellitus, type 2; P-selectin; Plasminogen activator inhibitor 1

LIPID LOWERING BY STATIN;

Objectives: To observe the effect of lipid lowering by atorvastatin administrationon platelet reactivity by measuring serum beta thromboglobulin concentration in male andfemale Sprague Dawley rats. Study Design: Randomized control trial (RCT). Place of study:The study was conducted at Physiology department, Army Medical College, Rawalpindi. Animalhandling, obesity induction, drug administration and sample collection were done at NationalInstitute of Health (NIH), Islamabad and biochemical assays were performed at Centre forResearch in Experimental and Applied Medicine (CREAM), Army Medical College, Rawalpindi.Period: 12 months. Material and Methods: Ninety healthy Sprague Dawley (male and female)rats were randomly selected and divided into three equal groups. Group I rats (normal control)were given normal chow diet for three weeks. Group II rats (obese control) were given high fatdiet for three weeks to induce obesity. Group III rats (obese treated) were given atorvastatinfor three weeks in a dose of 10 mg/kg/day orally by gavage method after obesity induction.Terminal blood sampling was done at the end of the study by intra-cardiac puncture. Bloodwas centrifuged to obtain serum and serum beta thromboglobulin was measured by usingEnzyme Linked Immunosorbant assay. Results: There was a significant (p &lt; 0.05) increasein serum B-TG concentration in obese rats as compared to normal control rats. Atorvastatinadministration to obese rats significantly (p &lt; 0.05) reduced serum B-TG concentration.Conclusions: Obesity increases and statin administration decreases platelet reactivity in highfat diet induced obese Sprague Dawley rats as reflected by serum B-TG concentration.

Effect of the FXa inhibitors Rivaroxaban and Apixaban on platelet activation in patients with atrial fibrillation

Rivaroxaban and Apixaban, increasingly used for stroke prevention in non-valvular atrial fibrillation (AF), might impact platelet reactivity directly or indirectly. By inhibition of Factor Xa (FXa) they preclude not only generation of relevant thrombin amounts but also block signalling of FXa via protease activated receptors. However, weather FXa-inhibition affects platelet haemostasis remains incompletely known. One hundred and twenty-eight patients with AF on chronic anticoagulation with either Rivaroxaban or Apixaban for at least 4 weeks were included in the study. In a time course group (25 on Rivaroxaban, 13 on Apixaban) venous blood samples were taken before NOAC medication intake in the morning as well as 2 and 6h afterwards. In 90 patients (Rivaroxaban n = 73, Apixaban n = 17) blood samples were drawn during left atrial RFA procedures before as well as 10 and 60min after the first heparin application (RFA group). Platelet reactivity analyzed by whole blood aggregometry (Multiplate Analyzer, Roche) in response to ADP, Collagen, TRAP and ASPI (arachidonic acid) was not altered by Rivaroxaban or Apixaban neither in the time course nor in the RFA group. Moreover, soluble P-selectin, Thrombospondin, von Willebrand Factor and beta thromboglobulin plasma levels, measured by ELISA, showed no statistically significant changes in both clinical settings for either FXa-inhibitor. The present study fails to demonstrate any significant changes on platelet reactivity in patients with AF under chronic Rivaroxaban or Apixaban medication, neither for trough or peak levels nor in case of a haemostatic activation in vivo as depicted by RFA procedures.

Platelets Cellular and Functional Characteristics in Patients with Atrial Fibrillation: A Comprehensive Meta-Analysis and Systematic Review.

BackgroundThis systematic review with meta-analysis aimed to determine the strength of evidence for evaluating the association of platelet cellular and functional characteristics including platelet count (PC), MPV, platelet distribution width (PDW), platelet factor 4, beta thromboglobulin (BTG), and p-selectin with the occurrence of atrial fibrillation (AF) and consequent stroke.Material/MethodsWe conducted a meta-analysis of observational studies evaluating platelet characteristics in patients with paroxysmal, persistent and permanent atrial fibrillations. A comprehensive subgroup analysis was performed to explore potential sources of heterogeneity.ResultsLiterature search of all major databases retrieved 1,676 studies. After screening, a total of 73 studies were identified. Pooled analysis showed significant differences in PC (weighted mean difference (WMD)=−26.93 and p<0.001), MPV (WMD=0.61 and p<0.001), PDW (WMD=−0.22 and p=0.002), BTG (WMD=24.69 and p<0.001), PF4 (WMD=4.59 and p<0.001), and p-selectin (WMD=4.90 and p<0.001).ConclusionsPlatelets play a critical and precipitating role in the occurrence of AF. Whereas distribution width of platelets as well as factors of platelet activity was significantly greater in AF patients compared to SR patients, platelet count was significantly lower in AF patients.

Hormonal and Metabolic Differences in Patients With Coronary Artery Disease

To prove the involvement of the autonomic nervous system in the formation of thrombotic status of the patients. 24 patients with myocardial infarction were enrolled in the study. Catecholamines levels were compared duing pain episodes and at rest. Patients were divided in to 2 groups according to the level of norepinephrine during the pain episode: Group 1-12 persons with the level of norepinephrine more than 500 pg/ml, and group 2-12 persons with a level below 500 pg/ml. Patients in group 1 the level of beta thromboglobulin and thromboxane were elevated, as well as there are changes of cAMP and cGMP, indicating increased thrombogenic activity. Particular attention was paid to the 8 patients in Group 1, in which the level of norepinephrine is maintained above 500 pg/ml both during pain and at rest (disseminated intravascular coagulation).

Dynamic changes in plasma tissue plasminogen activator, plasminogen activator inhibitor-1 and beta-thromboglobulin content in ischemic stroke

The aim of this paper is to investigate the corresponding variations of plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) activities, and beta–thromboglobulin (β-TG) content in patients during different stages of ischemic stroke. Ischemic stroke is a common disease among aging people and its occurrence is associated with abnormalities in the fibrinolytic system and platelet function. However, few reports focus on the dynamic changes in the plasma fibrinolytic system and β-TG content in patients with ischemic stroke. Patients were divided into three groups: acute, convalescent and chronic. Plasma t-PA and PAI-1 activities were determined by chromogenic substrate analysis and plasma β-TG content was detected by radioimmunoassay. Patients in the acute stage of ischemic stroke had significantly increased levels of t-PA activity and β-TG content, but PAI-1 activity was significantly decreased. Negative correlations were found between plasma t-PA and PAI-1 activities and between plasma t-PA activity and β-TG content in patients with acute ischemic stroke. There were significant differences in plasma t-PA and PAI-1 activities in the aged control group, as well as in the acute, convalescent and chronic groups. It can be speculated that the increased activity of t-PA in patients during the acute stage was the result of compensatory function, and that the increase in plasma β-TG level not only implies the presence of ischemic stroke but is likely a cause of ischemic stroke. During the later stages of ischemic stroke, greater attention is required in monitoring levels of PAI-1.

The influence of Erythropoietin on platelet activation, thrombin generation and FVII/active FVII in patients with AMI.

BackgroundErythropoietin (Epo) has been shown to improve myocardial function in models of experimental myocardial infarction, but has also been associated with a rise in thromboembolic events. Thus, the aim of this study was to investigate the influence of Epo on platelet activation and coagulation in patients with acute myocardial infarction (AMI).MethodsThe study was designed as a substudy of the randomised, double-blind, placebo controlled REVIVAL-3 (REgeneration of VItal Myocardium in ST-Segment EleVation MyocardiAL Infarction by Erythropoietin) study that investigated the effects of recombinant human Epo in AMI. Serial venous blood samples were collected before and after study medication. Circulating prothrombin fragment F1 + 2, FVII, active FVII, beta thromboglobulin (TG) and P-Selectin were measured before and 60 hours after randomization by immunoassay (n = 94). In a randomly selected subgroup platelet aggregation was measured using whole blood aggregometry (Multiplate Analyzer, n = 45).ResultsAfter 5 days an increase in FVII was observed after Epo as compared to placebo (P = 0.02), yet active FVII and prothrombin fragment F1 + 2 remained unchanged. Moreover, no statistically significant differences in circulating TG or P-selectin were observed between the groups. As an expected response to peri-interventional therapy with clopidogrel and aspirin, platelet aggregation after stimulation with ADP, TRAP, ASPI or collagen decreased 12 hours and 2 days after PCI. However, no difference between the Epo and the placebo group was observed.ConclusionAfter treatment with Epo in patients with AMI a slight increase in circulating FVII after Epo was not associated with an increase in active FVII, prothrombin fragment F1 + 2, TG or P-selectin. Moreover, platelet aggregation was not altered after treatment with Epo as compared to placebo.Trial registrationClinicalTrials.gov Identifier: NCT01761435

Identification Of Markers Of Thrombotic Risk and Response To Cytoreductive Intervention In Philadelphia-Chromosome Negative Myeloproliferative Neoplams

BackgroundThrombosis is a major cause of morbidity and mortality in the Philadelphia-chromosome negative myeloproliferative neoplasms (MPN). However, the pathogenesis of thrombosis in patients with MPN is poorly understood. MPNs are associated with elevated levels of inflammatory cytokines and abnormal platelet activation including elevated platelet factor 4 (PF4), B-thromboglobulin (B-TG) and p-selectin levels. However the relationship between these inflammatory markers and the onset of thrombosis is unclear. Current treatment guidelines recommend the use of cytoreductive agents to decrease thrombosis risk based on history of prior thrombosis and age. The effect of cytoreduction on inflammatory markers has only been partially characterized. Furthermore, current clinical guidelines fail to predict thrombotic events in all patients. Thus, more accurate risk stratification is necessary. AimTo determine if levels of p-selectin and PF4 correlate with thrombotic events and if levels of p-selectin and PF4 are affected by cytoreductive therapy. MethodsBiobanked samples from 16 patients with a confirmed diagnosis of chronic phase MPN (per WHO 2008 criteria) were included in this study. Seven patients had primary myelofibrosis, five had polycythemia vera, and four had essential thrombocythemia. Median age of patients was 65.5 (range 44-81). Fourteen patients had a JAK2 V617F mutation. Four patients with samples collected before and after thrombotic episodes, four patients with post-thrombotic samples, four without a history of thrombosis, and four patients with samples obtained before and after cytoreduction were analyzed. Patient characteristics are summarized in Table 1. Plasma samples were analyzed for levels of PF4 and p-selectin using commercially-available ELISA assays under standard conditions. [Display omitted] ResultsMeasurement of p-selectin levels in MPN patients with a history of a thrombotic event versus disease matched control MPN patients with no history of thrombosis demonstrated an increase in the level of p-selectin in patients with thrombosis. Elevated levels of PF4 were noted in only one patient who had a history of thrombosis, and who was maintained on Aspirin. This suggests that elevated levels of p-selectin may be an indicator of thrombosis risk in patients with MPN.Levels of PF4 and p-selectin were next assessed in patients who had suffered a thrombotic event, both before and after the event had occurred. No changes in p-selectin or PF4 levels pre and post thrombosis were noted.The effect of cytoreduction was measured using samples from patients pre- and post-cytoreduction. No differences in the level of PF4 were noted with cytoreduction. In contrast, reductions in p-selectin were noted in two patients in whom cytoreduction was achieved with Ruxolitinib, but not in two patients in whom cytoreduced with hydroxyurea or pomalidomide. This suggesting that Ruxolitinib may have role in thrombosis risk reduction.Platelet levels were recorded for all 16 patients. There was no difference in platelet levels in each group of patients. In contrast to the changes observed with p-selectin, there was no difference in platelet levels in patients with out a thrombotic event compared to those with a history of thrombosis. This suggests that platelet activation, as measured by p-selectin, may be a stronger indicator of thrombotic risk than platelet levels. ConclusionsImprovements in risk stratification of thrombotic risk for patients with MPN are needed. Platelet activation in MPNs is abnormal and may serve as an additional marker of thrombotic risk. Our results suggest that levels of p-selectin, but not PF4, may be associated with increased thrombotic risk. Furthermore, treatment with the JAK1/2 inhibitor Ruxolitinib resulted in reduction in levels of p-selectin, suggesting that the role of Ruxolitinib in preventing thrombotic event should be further investigated. Additional studies with larger numbers are in progress to validate these results. [Display omitted] Disclosures:Rampal:Foundation Medicine: Consultancy.

Platelet factor 4 and β-thromboglobulin in blood plasma of patients with acute exacerbation of chronic obstructive pulmonary disease

To explore the role of platelet factor 4 (PF4) and β-thromboglobulin (β-TG) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). A total of 71 AECOPD patients and 50 chronic obstructive pulmonary disease (COPD) patients within a stable stage were admitted into Beijing Chaoyang Hospital from January 2008 to June 2010. And another 40 healthy volunteers were selected as control group. The data of demographics, arterial blood gas analysis and pulmonary function parameters was collected and analyzed. The plasma levels of PF4 and β-TG were measured by enzyme-linked immunosorbent assay (ELISA). Platelet count was measured by hematology analyzer. Statistical analysis was used for PF4, β-TG and platelet count. Spearman rank correlation was used for correlation analysis. No differences in age and gender existed among the AECOPD, stable and control groups. The plasma level of PF4 in the AECOPD group (2.28 µg/L) was significantly higher than that of the stable group (2.01 µg/L) and control group (1.57 µg/L) (both P < 0.05). The level of β-TG in AECOPD was 2.32 µg/L and it was significantly higher than that of the stable group (1.85 µg/L) and control group (1.29 µg/L) (both P < 0.05). The differences in platelet counts were insignificant between the AEC OPD group ((196 ± 67) ×10(9)/L), stable group ((194 ± 50) ×10(9)/L) and control group ((190 ± 48) ×10(9)/L). AECOPD group was divided into moderate, severe and very severe groups by pulmonary function parameters. The levels of PF4 and β-TG in very severe group were significantly higher than those in moderate and severe groups (P < 0.05). A significant positive correlation was observed between PF4 and β-TG (r = 0.518, P < 0.01). The levels of PF4 and β-TG were negatively correlated with FEV1%, FEV1/FVC and PaO2 (all P < 0.05). Abnormal platelet activation exists in AECOPD. And the levels of PF4 and β-TG may reflect the severity of AECOPD and can be used as the markers of estimating prethrombotic state.

Evaluation of platelet activation, fibrinolysis, and hemostatic activation during high dose dobutamine stress echocardiography

Acute myocardial infarction during high-dose dobutamine stress echocardiography (DSE) has been reported in patients with no indication of severe obstructive coronary artery disease, but the mechanism of thrombosis remains unclear. We hypothesized that an increase in platelet and hemostatic activation secondary to high dose dobutamine might be a contributing factor. Twelve patients undergoing outpatient DSE and with either a normal DSE results (n = 11) or normal coronaries by follow-up angiography (n = 1) were included. Patients with documented ischemia were excluded to eliminate the possibility of ischemia-induced platelet activation. Three separate samples of blood were drawn at baseline, peak dobutamine infusion and 30 minutes after the end of infusion. Blood was assayed for beta-thromboglobulin (BTG) as a platelet activation marker, D-Dimer as a fibrinolytic marker, and prothrombin fragment 1.2 (F1.2) as a marker of thrombin formation. Using ANOVA analysis, there were no significant differences between BTG, D-Dimer or F1.2 at baseline, peak dobutamine and half-hour into recovery. In this study, high dose DSE did not result in a significant increase in platelet, hemostatic or fibrinolytic activation in patients with low risk for obstructive coronary artery disease.

The role of platelet TLR4 expression in the pathogensis of thrombocytopenia in sepsis

Objective To unravel the relationship between Toll-like receptor 4 (TLR4) expression in platelets and the activation of platelet in thrombocytopenia (TCP) in case of sepsis. Method A total of 64 patients with sepsis were prospectively studied with control. Platelet count (PC), mean platelet volume (MPV),platelet distribution width (PDW),platelet TLR4 expression, platelet PAC-1 expression, sCD40L and TNF-α concentrations were compared between healthy control group (15 cases) and sepsis group on admission and 3 d,Sd,and 9 days after admission. The changes of MPV and PDW in TCP and non-TCP subgroups of sepsis before and after treatment were recorded. Prognostic index was analyzed. Results The PC was lower in sepsis group (P=0.006), and MPV and PDW were higher in sepsis group than those in healthy control group (P = 0.046, P =0.001). Platelet TLR4 and PAC-1 expressions, and sCD40L and TNF-α levels also increased more significantly in sepsis group (P ＜ 0.001). PAC-1 expression and TNF- level were higher in TCP group than those in non-TCP group before and after treatment (P = 0.023, P = 0.011). The sCD40L concentration and platelet TLR4 expression were significantly higher in treated TCP groups than in non-TCP group (P = 0.047, P = 0.001). Compared with non-TCP,the rate of bleeding was higher (P = 0.024) and the length of ICU stay was longer (P = 0.013).The APACHE Ⅱ score and the 28-day mortality were higher in TCP group (P ＜ 0.01, P = 0.048). Conclusions The elevation of platelet TLR4 expression in sepsis along with platelet activation is closely related to the incidence of thrombocytopenia. The occurrence of TCP is a poor prognosis sign of sepsis. Key words: Sepsis; Thrombocytopenia; Toll-like receptor; Platelet activation; Glycoprotein Ⅱb/Ⅲa; Soluble CD40 ligand ; β-Thromboglobulin; Tumor necrosis factor-α; Interleukin-8

Platelet Toll-like receptor expression modulates lipopolysaccharide-induced cytokines production

Objective To affirm the expression of Toll like receptor 4 (TLR4) on the surface membrane of platelet and to explore the immunomodulatory factors[(interlukine-8(IL-8),β-thromboglobulin(β-TG), soluble CD40 ligand(sCD40L)] released by platelets after platelets stimulated by TLR4 ligand.Methods TLR4 expressed on the platelet was detected by flow cytometry. Monoclonal anti-human FcγRⅡantibody(Ⅳ.3)-treated human platelets were cultured with LPS in the presence or absence of blocking monoclonal antibody to human TLR4. The release of IL-8, β-TG, sCD40L were measured by specific enzymelinked immunosorbent assay. Results Human platelets could express functional TLR4. The detection rate of TLR4 on platelets were decreased after LPS involvement(P<0.01). It was noted that sCD40L and β-TG were present in large concentration in the release of platelets stimulated by TLR4 ligand but the release of IL-8 was independent of platelet activation after TLR4 engagement. The concentration of sCD40L and β-TG had no statistical difference between 1-5 μg/ml LPS. The effects of LPS on the modulation of secretory factors were attenuated by preincubation of platelets with an anti-TLR4 monoclonal antibody. Conclusion The TLR4 on platelet could recognize and link LPS, induce the release of sCD40L, β-TG by platelet, but could not influence IL-8. Key words: Platelet; Toll like receptor 4; β-thromboglobulin; Soluble CD40 ligand

Effects of time of day and acute resistance exercise on platelet activation and function

The present study was designed to ascertain the interaction between time of day and resistance exercise on platelet activation and function. Ten healthy male subjects (age, 29.3 +/- 4.5 yr) undertook identical bouts of resistance exercise on two separate occasions. Tests were randomised and performed at two different time of day (08:00 and 20:00 h). Subjects performed 3 sets of 7 repetitions of six exercises at 80% of 1RM, which was followed by 30 min recovery. Beta-thromboglobulin (B-TG) and platelet indices were measured at rest, post-exercise and at the completion of recovery. Platelet aggregation was determined in platelet rich plasma using collagen and three different concentrations of adenosine-5'-diphosphate. Platelet aggregations induced by different aggregating agents at rest were significantly higher in the morning (p < 0.05). Although platelet aggregations induced by collagen and ADP did not change in response to resistance exercise, significant differences between the results in the morning and evening trials were observed (p < 0.01). These differences emulated the differences observed at rest. A significant (P < 0.05) increase in B-TG was found following exercise with no difference between morning and evening trials. It was concluded that resistance exercise induces significant changes in platelet activation, irrespective of time of day, as assessed by beta-thromboglobulin.