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Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Veronika Černotová Supervisor: prof. Přemysl Mladěnka, PharmD., Ph.D. Consultant: Lukáš Konečný, MSc. Title of diploma thesis: The influence of LDL-apheresis on aggregation of blood platelets, blood coagulation and the effect of standard drugs LDL-apheresis is a method that removes LDL-cholesterol (LDL-C) from the blood. It is used to treat familial hypercholesterolemia (FH), a genetic disorder causing high LDL-C levels and an early development of cardiovascular diseases. Blood platelets and coagulation system play an important role in these diseases and their activity is also affected by lipids. The aim of this thesis was to analyze possible differences in platelet aggregation and blood coagulation in patients suffering from FH. Two methods of treatment in this group were compared - lipid apheresis and PCSK9Ab (proprotein convertase subtilisin/kexin type 9 monoclonal antibodies). The observed parameters were also compared with age-matched healthy volunteers. Our cohort consisted of 15 patients and 15 healthy donors. Six patients were treated with lipid apheresis and also PCSK9Ab, six subjects only with PCSK9Ab. Platelet aggregation was measured with an impedance aggregometer using 7 different...

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Júlia Minarovičová Supervisor: prof. Přemysl Mladěnka, Pharm.D., Ph.D. Title of diploma thesis: Comparison of platelet aggregation in healthy population Platelets have an irreplaceable role in the process of aggregation. Nevertheless, their increased activity is associated with the development of many cardiovascular diseases. This process can be influenced by clinical used substances from the group of antiplatelet drugs, which differ in their effectiveness within the population. Within this study, platelet aggregation was tested using impedance aggregometry, whose principle is the change in electrical impedance between electrodes caused by the adhesion of activated platelets. Firstly, whole blood was incubated with clinically used antiplatelet drugs (ticagrelor, vorapaxar, and acetylsalicylic acid) and a flavonoid metabolite, 4-methylcatechol. Subsequently, a platelet aggregation inducer (ADP, thrombin receptor activating peptide 6 /TRAP/, collagen, arachidonic acid, ristocetin, U-46619, and platelet-activating factor /PAF/) was added, and the process was monitored for 6 minutes. The most potent inhibitor of the aggregation induced by arachidonic acid was acetylsalicylic acid in a concentration of 70 μM...

Platelets are valuable, but highly perishable, blood components used in the treatment of, among others, viral dengue fever, blood-related illness, and post-chemotherapy following cancer. Given the short shelf-life of 3–5 days and a highly volatile supply and demand pattern, platelet inventory allocation is a challenging task. This is especially prevalent in emerging economies where demand variability is more pronounced due to neglected tropical diseases, and a perpetual shortage of supply. The consequences of which have given rise to an illegal ‘red market’. Motivated by experience at a regional hospital in India, we investigate the problem of platelet allocation among three priority-differentiated demand streams. Specifically we consider a central hospital which, in addition to internal emergency and non-emergency requests, faces external demand from local clinics. We analyze the platelet allocation decision from a social planner’s perspective and propose an allocation heuristic based on revenue management (RM) principles. The objective is to maximize total social benefit in a highly supply-constrained environment. Using data from the aforementioned Indian hospital as a case study, we conduct a numerical simulation and sensitivity analysis to evaluate the allocation heuristic. The performance of the RM-based policy is evaluated against the current sequential first come, first serve policy and two fixed proportion-based rationing policies. It is shown that the RM-based policy overall dominates, serves patients with the highest medical urgency better, and can curtail patients’ need to procure platelets from commercial sources.

Background The contact factor XII (FXII) activates upon contact with a variety of charged surfaces. Activated FXII (FXIIa) activates factor XI, which activates factor IX, resulting in thrombin generation, platelet activation, and fibrin formation. In both in vitro and in vivo rabbit models, components of medical devices, including extracorporeal oxygenators, are known to incite fibrin formation in a FXII‐dependent manner. Since FXII has no known role in hemostasis and its inhibition is therefore likely a safe antithrombotic approach, we investigated whether FXII inhibition also reduces accumulation of platelets in extracorporeal oxygenators. Objectives We aimed to determine the effect of FXII inhibition on platelet deposition in perfused extracorporeal membrane oxygenators in nonhuman primates. Methods A potent FXII neutralizing monoclonal antibody, 5C12, was administered intravenously to block contact activation in baboons. Extracorporeal membrane oxygenators were temporarily deployed into chronic arteriovenous access shunts. Radiolabeled platelet deposition in oxygenators was quantified in real time using gamma camera imaging. Biochemical assays were performed to characterize the method of action of 5C12. Results The anti‐FXII monoclonal antibody 5C12 recognized both the alpha and beta forms of human and baboon FXII by binding to the protease‐containing domain, and inhibited FXIIa activity. Administration of 5C12 to baboons reduced platelet deposition and fibrin formation in the extracorporeal membrane oxygenators, in both the presence and absence of systemic low‐dose unfractionated heparin. The antiplatelet dose of 5C12 did not cause measurable increases in template bleeding times in baboons. Conclusions FXII represents a possible therapeutic and safe target for reducing platelet deposition and fibrin formation during medical interventions including extracorporeal membrane oxygenation.

Objective Coagulation indexes may be useful survival biomarkers for cervical cancer. This study evaluated the ability of hemoglobin, red blood cells (RBCs), platelets, and D-dimer levels to predict post-hysterectomy survival outcomes in patients with stage IA1 to IIA2 cervical cancer. Methods In this retrospective study, coagulation-related indexes were compared between the anemia and non-anemia groups. Independent variables were analyzed by the Cox proportional hazards model. Survival was assessed by the Kaplan–Meier method with the log-rank test. Mortality predictions were evaluated by receiver operating characteristic curves. Results Among this study’s 1088 enrolled patients, 152 had anemia. The 10-year overall survival and recurrence-free survival rates were 90.8% and 86.5%, respectively. Hemoglobin, RBC, and the rate of abnormal platelet counts were significantly lower in the anemia group. Abnormal preoperative D-dimer was an independent factor for recurrence-free survival. Receiver operating characteristic curves showed that D-dimer had area under the curve of 0.734 (cut-off value: 0.685, sensitivity: 85.7%, and specificity: 64.0%). Hemoglobin and platelets had areas under the curves of 0.487 and 0.462, respectively. Conclusion Preoperative D-dimer was the most effective prognostic predictor for patients with cervical cancer. The prognosis of patients with cervical cancer was poorer if their D-dimer levels were >0.685 mg/L.

The effect of dandelion root and its various ingredients on the biological functions of blood platelets has not been well investigated. Thus, the objective of our in vitro study was to examine the five root fractions (A–E), differing in chemical composition, for changes induced in the human platelets’ model using selected hemostatic parameters. As a result, the best anti-platelet potential was shown by preparation enriched with hydroxyphenylacaetate inositol esters – PIEs (fraction C). On the other hand, the best overall protective effect against oxidation of lipids and proteins of platelets, and the best inhibitory effect on the generation of O2− were observed in the presence of fraction A (SL-amino acid adducts enriched fraction). Thus, PIEs and SLs rich plant organs, such as dandelion root, may be considered as potentially suitable additives for functional food products used in prophylaxis and treatment of cardiovascular diseases associated with hyperactivation of blood platelets.

In severe COVID-19, which is characterized by blood clots and neutrophil-platelet aggregates in the circulating blood and different tissues, an increased incidence of cardiovascular complications and venous thrombotic events has been reported. The inflammatory storm that characterizes severe infections may act as a driver capable of profoundly disrupting the complex interplay between platelets, endothelium, and leukocytes, thus contributing to the definition of COVID-19-associated coagulopathy. In this frame, P-selectin represents a key molecule expressed on endothelial cells and on activated platelets, and contributes to endothelial activation, leucocyte recruitment, rolling, and tissue migration. Briefly, we describe the current state of knowledge about P-selectin involvement in COVID-19 pathogenesis, its possible use as a severity marker and as a target for host-directed therapeutic intervention.

Chronic oxidative stress (OS) can be an important factor of acute myeloid leukemia (AML) progression, however, there are no data on the extent/consequence of OS after transfusion of packed red blood cells (pRBCs) and platelet concentrates (PCs), which are commonly used in the treatment of leukemia-associated anemia and thrombocytopenia. We aimed to investigate the effects of pRBC/PC transfusion on the OS markers, i.e., thiol and carbonyl (CO) groups, 3-nitrotyrosine (3-NT), thiobarbituric acid reactive substances (TBARS), advanced glycation end products (AGE), total antioxidant capacity (TAC), SOD, GST, and LDH, in the blood plasma of AML patients, before and 24 h post-transfusion. In this exploratory study, 52 patients were examined, of which 27 were transfused with pRBCs and 25 with PCs. Age-matched healthy subjects were also enrolled as controls. Our results showed the oxidation of thiols, increased 3-NT, AGE levels, and decreased TAC in AML groups versus controls. After pRBC transfusion, CO groups, AGE, and 3-NT significantly increased (by approximately 30, 23, and 35%, p &lt, 0.05, p &lt, 0.05, and p &lt, 0.01, respectively) while thiols reduced (by 18%, 0.05). The PC transfusion resulted in the raise of TBARS and AGE (by 45%, 0.01 and 31%, 0.001), respectively). Other variables showed no significant post-transfusion changes. In conclusion, transfusion of both pRBCs and PCs was associated with an increased OS, however, transfusing the former may have more severe consequences, since it is associated with the irreversible oxidative/nitrative modifications of plasma proteins.

Objective: Fibrin is considered to strengthen thrombus formation via integrin αIIbβ3, but recent findings indicate that fibrin can also act as ligand for platelet glycoprotein VI. Approach and Results: To investigate the thrombus-forming potential of fibrin and the roles of platelet receptors herein, we generated a range of immobilized fibrin surfaces, some of which were cross-linked with factor XIIIa and contained VWF-BP (von Willebrand factor-binding peptide). Multicolor microfluidics assays with whole-blood flowed at high shear rate (1000 s −1 ) indicated that the fibrin surfaces, regardless of the presence of factor XIIIa or VWF-BP, supported platelet adhesion and activation (P-selectin expression), but only microthrombi were formed consisting of bilayers of platelets. Fibrinogen surfaces produced similar microthrombi. Markedly, tiggering of coagulation with tissue factor or blocking of thrombin no more than moderately affected the fibrin-induced microthrombus formation. Absence of αIIbβ3 in Glanzmann thrombasthenia annulled platelet adhesion. Blocking of glycoprotein VI with Fab 9O12 substantially, but incompletely reduced platelet secretion, Ca 2+ signaling and aggregation, while inhibition of Syk further reduced these responses. In platelet suspension, glycoprotein VI blockage or Syk inhibition prevented fibrin-induced platelet aggregation. Microthrombi on fibrin surfaces triggered only minimal thrombin generation, in spite of thrombin binding to the fibrin fibers. Conclusions: Together, these results indicate that fibrin fibers, regardless of their way of formation, act as a consolidating surface in microthrombus formation via nonredundant roles of platelet glycoprotein VI and integrin αIIbβ3 through signaling via Syk and low-level Ca 2+ rises.

Patients bearing polymorphisms termed CYP2C19 loss of function (LoF) alleles and ABCB1-C3435T may do not properly respond to standard dosage of clopidogrel and have an increased risk of thrombosis. Moreover, co-administration of proton pump inhibitors (PPIs) and clopidogrel may attenuate the antiplatelet effect. The role of pharmacogenetics and PPIs/clopidogrel drug-drug interaction has been extensively investigated in patients with acute coronary syndrome after stent implantation (ACS/PCI), while data in patients undergoing vascular surgery are scarce. Here we have performed a systematic review to evaluate the available literature in such a clinical setting and have discussed the controversies about the use of CYP2C19 pharmacogenetics and platelet function testing to personalize clopidogrel treatment. In addition, we have made a comparison of the literature data with our findings concerning patients eligible for vascular surgery and treated with clopidogrel, in whom we used a combined management based on the CYP2C19 and ABCB1 pharmacogenetic testing with monitoring of therapeutic adherence and PPIs-clopidogrel interaction. Both our data and those produced during both observational studies and randomized clinical trials confirm the validity of pharmacogenetics to personalize clopidogrel treatment and stress the importance to make a drug monitoring considering all the known variables, potentially responsible for treatment failure. However, the American Heart Association and the European Cardiovascular Society recommend against the routine use of clopidogrel pharmacogenetic testing. An update of the international guidelines on antiplatelet therapy, incorporating the evidence related to CYP2C19 pharmacogenetics and PPIs-clopidogrel drug-drug interactions is warranted both in ACS/PCI patients and subjects undergoing vascular surgery.

Antiplatelet therapy is one of the cornerstones in the acute treatment of patients with ST-elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI). However, hemodynamic changes and delayed intestinal absorption of P2Y12 inhibitors leads to a delay in the onset of antiplatelet effects resulting in a gap of platelet inhibition. Several strategies have been proposed to bridge this gap, such as pre-hospital administration of antiplatelet therapy, higher loading doses of P2Y12 inhibitors, crushing or chewing tablets, subcutaneous or intravenous administration of platelet inhibitors, or use of pain relievers alternative to opioids that do not delay intestinal absorption of oral platelet inhibitors. These strategies may improve platelet inhibition with the goal of optimizing clinical outcomes in the acute phase of STEMI. In this review we present current and future insights for bridging the gap in platelet inhibition in STEMI patients undergoing primary PCI. (c) 2020 Published by Elsevier B.V.Superscript/Subscript Available

Aim: This systematic review and meta-analysis aims to assess the additive effect of leukocyte and platelet-rich fibrin (L-PRF) on coronally advanced flap (CAF) procedures in root coverage of Miller’s class I and II gingival recession defects. Review methodology: A comprehensive search in MEDLINE (PubMed), Scopus and CENTRAL (the Cochrane Central Register of Controlled Trials), along with an additional hand search, provided eight randomized clinical trials to be included in this review. A total of 167 patients with 470 gingival recession defects were analyzed. A meta-analysis was carried out to assess the change in gingival thickness (GT), width of keratinized gingiva (WKG), root coverage percentage (%RC), clinical attachment level (CAL) and recession depth (RD) at all follow-ups between CAF alone and CAF + L-PRF groups for all included studies. A subgroup analysis was carried out based on recession type (single/multiple). Results: Overall, a significant improvement in GT, CAL and RD was found when treated with CAF + L-PRF. There was a trend for a positive effect in terms of an increase in WKG when using L-PRF, especially in the treatment of single recession, though significance was not achieved (p = 0.08 overall). The results of heterogeneity among the subgroups were varied and were found to be greater than 91.3% for GT and 32.8% for WKG. Conclusion: L-PRF when used in addition to CAF showed favorable results for the treatment of class I and II gingival recession defects.

Introduction. Congenital asplenia is an extremely rare condition that can be separate entity due to a specific defect of spleen development or may occur in the context of a malformation syndrome. The patients with asplenia have thrombocytosis and susceptibility to life-threatening infections. Case report. We report a 52-years-old female patient with isolated congenital asplenia with pseudothrombocytopenia and giant platelets. Estimation of platelets life with radioactive indium showed normal lenght of platelets life (9 days). Flow cytometric analysis of platelets showed normal expression of CD41 and CD42b antigens. The mean platelet diameter of asplenic patient measured on the ultrathin sections by the transmission electron microscope was significantly higher than in the healthy individuals (3.81 ? 1.16 ?m vs. 2.37 ? 0.61 ?m, p < 0.05). There were very few platelets of diameter more than 4 ?m found in healthy individuals (around 1%) in comparison to > 40% of the patient?s platelets. The ultrastructural studies revealed normal morphology of megakaryocytes. The platelets were uniformly spheroid in shape with conspicuous pseudopodia and the centralization of granules. There were no marginal bands of microtubules inside the platelets. Conclusion. The first case of congenital asplenia with the pseudothrombocytopenia and giant platelets is presented. We discussed the pathogenesis of giant platelets and possible relation of observed ultrastructural changes of platelets with the severe three-vessel coronary artery disease in our patient.

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

Diagnostic value of blood platelet (PLT) and serum total bilirubin (TBIL) for central serous chorioretinopathy (CSC) was investigated. A total of 537 patients with CSC and 182 people with normal physical conditions were selected from June 2012 to August 2016. The 537 patients included 294 males and 243 females with an average age of 45.5±17.8 years, and all patients were treated in the Department of Ophthalmology of Yantai Hospital of Traditional Chinese Medicine and the Department of Ophthalmology of Yantai Liuhuangding Hospital. Clinical data of the patients were retrospectively analyzed. The 182 people with normal physical conditions included 103 males and 79 females with an average age of 43.6±15.2 years, and they were set as the control group. PLT and TBIL tests at admission and after treatment were collected and compared between CSC and the control group to analyze the diagnostic values of PLT and TBIL for CSC. PLT level in the CSC group was significantly higher than that in the control group, but TBIL level in the CSC group was significantly lower than that in the control group (p

Background: It is known that there is a definite association between platelet distribution width (PDW) and poor prognosis in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). However, there are no data available regarding the prognostic significance of PDW for in-stent restenosis (ISR) in patients with CAD and T2DM. We aimed to determine the value of PDW on admission that predicted ISR in patients with CAD and T2DM. Methods: Between January 2012 and December 2013, a total of 5232 consecutive patients diagnosed with CAD and T2DM undergoing percutaneous coronary intervention were admitted. Three years of retrospective follow-up was undertaken. A total of 438 patients with second angiography operations were included. ISR was defined as ≥50% luminal stenosis of the stent or peri-stent segments. Continuous data were presented as the mean ± standard deviation or median (P25, P75) and were compared by one-way analysis of variance or Kruskal-Wallis H-test. Categorical variables were presented as percentages and were compared by Chi-square test or Fisher’s exact test. The association between PDW and ISR was calculated by logistic regression analysis. A two-sided value of P < 0.05 was considered statistically significant. Statistical analyses were performed by SPSS version 22.0 for windows. Results: Fifty-nine patients with ISR, accounting for 13.5% of the total, were included. ISR was significantly more frequent in patients with higher PDW quartiles compared with lower quartiles. We observed that PDW had a strong relationship with mean platelet volume (r = 0.647, 95% confidence interval [CI]: 0.535–0.750, P < 0.0001). The receiver-operating characteristic curves showed that the PDW cutoff value for predicting ISR rate was 13.65 fl with sensitivity of 59.3% and specificity of 72.4% (area under curve [AUC] = 0.701, 95% CI: 0.625–0.777, P < 0.001). Multivariate analysis showed that the risk of ISR increased approximately 30% when PDW increased one unit (odds ratio [OR]: 1.289, 95% CI: 1.110–1.498, P = 0.001). Patients with higher PDW, defined as more than 13.65 fl, had a 4-fold higher risk of ISR compared with lower PDW (OR: 4.241, 95% CI: 1.879–9.572, P = 0.001). Furthermore, when patients were divided by PDW quartiles values, PDW was able to predict ISR (Q2: OR = 0.762, 95% CI: 0.189–3.062, P = 0.762; Q3: OR = 2.782, 95% CI: 0.865–8.954, P = 0.086; and Q4: OR = 3.849, 95% CI: 1.225–12.097, P = 0.021, respectively; P for trend

Background: Immature platelet fraction (IPF) estimation is a non-invasive and sensitive test that is available on recently introduced Sysmex XN-series of automated haematology analysers. It is a direct cellular indicator of thrombopoiesis. The aim of this study was to establish reference intervals for IPF, for both absolute (A-IPF) and percentage (%-IPF) measurements.Material and methods: A total of 2366 samples that met the inclusion criteria were assayed for full blood count on the Sysmex XN-10 and a non-parametric percentile method was used for calculating the reference intervals.Results: After the outliers were excluded, the reference interval for %-IPF and A-IPF on Sysmex XN-10 were 1.6–10.1% and 4.37–23.21 × 109/L in total individuals, respectively. There was a statistical significance noted between the sexes (p = .004) for %-IPF, therefore a sex-specific reference interval was established, which was 1.8–10.0% for the males and 1.5–10.1% for females. No significant difference in sex status for A-IPF and age status for both %-IPF and A-IPF was observed. A very poor correlation was estimated between age versus %-IPF, ρ = 0.0156, and age versus A-IPF, ρ = −0.0023, indicating that there is no overall biological relationship between age and these parameters. As expected, a strong correlation between %-IPF and A-IPF was noted which could be attributed to their inter-relatedness.Conclusions: This large-scale study showed comparable reference intervals with the previous studies for %-IPF and A-IPF in a UK population. It found the need to establish sex-specific reference intervals for %-IPF, but not for A-IPF, whereas reference intervals were found to be stable across the age range.

Introduction: Type 2 diabetes mellitus, due to its high incidence and mortality rates, is a major health problem around the world. Also, the type II diabetes is a type of metabolic disorder characterized by increased blood glucose, which is due to insulin resistance, insulin deficiency, or both. The current study aimed to assess the mean platelet volume (MPV) in type 2 diabetes patients compared to nondiabetics, and determine the correlation between MPV and fasting blood glucose, glycosylated hemoglobin (HbA1c). Methods: This case-control study was conducted on all patients (n = 120) diagnosed with diabetes referred to the clinical laboratory of Bechr('39')sat Hospital in Hamadan City, Iran, during 2015-2016. The patients were divided into the two groups of case and control (n = 60, each group). The mean platelet volume was measured by an automated blood cell counter. The blood glucose and HbA1c levels were also measured in both groups. Data were analyzed using the Chi-square, t test and Mann-Whitney tests with the SPSS software version 16. The significance level was equal to 0.05. Results: The mean age of the control group was 41.78 years and that of the case group was 41.58 years. The mean platelet volume was 8.42% in the case group and 7.74% in the control group, which showed a significant difference between the two groups (P = 0.001). The mean platelet volume in people with HbA1c less than 7 in the case group was less than those who had HbA1c more than 7 and this difference was statistically significant (P = 0.001). Conclusion: The mean platelet volume in diabetic patients was significantly higher than in the nondiabetic group. So, it seems that the elevated MPV can be used as a parameter for the diagnosis of vascular complications of diabetes.

The aim of the study was to determine the morphological changes in the cellular elements of blood in rats of different ages under conditions of prolonged hypokinesia. Research into the structural and functional properties of platelets and erythrocytes was carried out by electron microscope and by biochemical methods in 90 mature male rats aged 2, 12 and 24 months. We found that in young (2 month animals) there was a significant increase in the relative content of activated platelets while the normal content of aggregated and degranulated forms with the appearance of single platelets was maintained with an imbalance of alpha and delta granules. In 12-month-old animals, platelet hemostasis disorders were manifested by a significant increase in the relative content of activated platelets (by 125.8–134.7%) with an increase in aggregated and degranulated forms, the appearance of numerous platelets with an imbalance of alpha- and delta-granules, and reduction of mitochondria (by 24.9–27.8%). In 24 month old animals there was a sharp violation of platelet hemostasis due to a significant increase in the content of activated, degranulated and aggregated platelets, the release of the majority of granules, the development of intravascular platelet hyperactivation, an increase in the number of reversible and irreversibly transformed erythrocytes, an increase in the level of aggregation, in particular the appearance of complex cellular aggregates and bizarre forms of red blood cells. The greatest degree of manifestation of morpho-functional changes was revealed in animals aged 24 months, with relative stability of the hemostasis system in 2 and 12 month old animals. Our results showed that irrespective of age, the degree of disturbance of platelet-erythrocyte hemostasis rose as the period of hypokinesia increased and also depended on the increase in the level of serum creatinine. Taken together, intravascular platelet hyperactivation, an imbalance in the content of all types of granules, the transformation of surface cytoarchitectonics of erythrocytes, and the formation of platelet aggregates may play the role of an early predictor of the development of hypokinetic disease

Honey is a sweet, viscous syrup produced by the honey bee (Apis mellifera). It is probably the first natural sweetener ever discovered, and is currently used as a nutritious food supplement and medicinal agent. The aim of the present mini-review is to summarize and update the current knowledge regarding the role of honey in CVDs based on various experimental models. It also describes the role of its phenolic compounds in treating CVDs. Many such phenolic and flavonoid compounds, including quercetin, kaempferol, apigenin, and caffeic acid, have antioxidant and anti-platelet potential, and hence may ameliorate cardiovascular diseases (CVDs) through various mechanisms, such as by decreasing oxidative stress and inhibiting blood platelet activation. However, as the phenolic content of a particular type of honey is not always known, it can be difficult to determine whether any observed effects on the human cardiovascular system may be associated with the consumption of honey or its constituents. Therefore, further experiments in this area are needed.

Background: This study aimed to define the sex-divided reference intervals for platelet indices (mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR) and plateletcrit (PCT)) on the Sysmex XN-10. Methods: A total of 2376 samples were assayed for full blood count on the Sysmex XN-10 haematology analyzer. After removing the outliers, reference intervals were calculated using the mean ± 2SD. The P value 0.05 was adopted to denote statistical significance. Results: There was a statistical significance (α = 0.05) between sex-divided reference intervals for MPV (p = 0.007), P-LCR (p = 0.015) and PCT (p

Continuous flow ventricular assist devices (cfVADs) while effective in advanced heart failure, remain plagued by thrombosis related to abnormal flows and elevated shear stress. To limit cfVAD thrombosis, patients utilize complex anti-thrombotic regimens built upon a foundation of aspirin (ASA). While much data exists on ASA as a modulator of biochemically-mediated platelet activation, limited data exists as to the efficacy of ASA as a means of limiting shear-mediated platelet activation, particularly under elevated shear stress common within cfVADs. We investigated the ability of ASA (20, 25 and 125 μM) to limit shear-mediated platelet activation under conditions of: 1) constant shear stress (30 dynes/cm2and 70 dynes/cm2); 2) dynamic shear stress, and 3) initial high shear exposure (70 dynes/cm2) followed by low shear exposure-i.e. a platelet sensitization protocol, utilizing a hemodynamic shearing device providing uniform shear stress in vitro. The efficacy of ASA to limit platelet activation mediated via passage through a clinical cfVAD system (DeBakey Micromed) in vitro was also studied. ASA reduced platelet activation only under conditions of low shear stress (38% reduction compared to control, n = 10, p < 0.004), with minimal protection at higher shear stress and under dynamic conditions (n = 10, p > 0.5) with no limitation of platelet sensitization. ASA had limited ability (25.6% reduction in platelet activation rate) to modulate shear-mediated platelet activation induced via cfVAD passage. These findings, while performed under "deconstructed" non-clinical conditions by utilizing purified platelets alone in vitro, provide a potential contributory mechanistic explanation for the persistent thrombosis rates experienced clinically in cfVAD patients despite ASA therapy. An opportunity exists to develop enhanced pharmacologic strategies to limit shear-mediated platelet activation at elevated shear levels associated with mechanical circulatory support devices.

Spent hop extract (SHE) is hypothesized to possess multifaceted anticoagulant effect and to reduce platelet reactivity in a direct manner and to improve the antiplatelet action of endothelium. The results demonstrated that SHE, rich in flavanols (50% of total phenolic compounds), hydroxycinnamic acids, proanthocyanidin oligomers, flavan-3-ol monomers, and flavonol glycosides, inhibited ADP-induced platelet aggregation up to 11% for 7.5 µg/ml or up to 23% for 15 µg/ml, P 0.05. Additionally, SHE ameliorated anticoagulant activity of human endothelial cells to significantly reduce platelet reactivity. This effect could be related to the increased expression/activity of the ecto-ADPase (CD39). ADP-induced platelet reactivity was reduced in the case of platelets incubated with the extract-treated endothelial cells compared to the untreated cells. Diabetic rats fed with SHE demonstrated longer survival time than the group treated with placebo. In conclusion, our study provided evidence for a potential beneficial role of SHE in the regulation of platelet and endothelial function.

Inflammatory bowel disease (IBD) includes ulcerative colitis and Crohn's disease. It is a group of chronic disorders characterized by inflammation of the gastrointestinal track with unknown etiology. Currently applied biomarkers include CRP, ESR, pANCA, ASCA, and fecal calprotectin. The etiopathogenesis of IBD is multifactorial. In patients with IBD in inflamed alimentary tract mucosa the number of recruited monocytes and activated macrophages which are source of cytokines. In IBD, the exacerbation is accompanied by thrombocytosis. Platelets play a crucial role in the hemostasis and inflammatory response. Selectins, which regulates the hemostasis and inflammatory response, stimulates the secretion of many inflammatory mediators such as β-thromboglobuline, CD40L, fibrinogen, IL-1β, platelet factor-4. In the course of IBD the following changes are observed: an increase in the number of platelets (reactive thrombocytosis), PDW and PCT, reduction in MPV, increased production and excretion of granular content products (P-selectin, GP53, β-TG, PF-4, vWF, fibrinolytic inhibitors).

To engineer functional tissue substitutes, it is required a multi-component, multi-scale approach that combines both physical, chemical and biological cues. Fiber-based techniques have been explored in the field of tissue engineering to produce structures recapitulating tissue architecture and mechanical properties. In this work, we engineered biofunctional composite living fibers (CLF) as multi-compartment fibers with a mechanically competent core and a hydrogel layer. For this purpose, commercial silk suture threads were coated with a platelet lysate (PL) hydrogel by first embedding the threads in a thrombin solution and then incubating in PL. The fabrication set-up was optimized and the biological performance was studied by encapsulating human adipose-derived stem cells (hASCs). The developed coating process rendered CLF with a homogenous PL hydrogel layer covering suture threads. Encapsulated hASCs were viable up to 14 days in culture and were able to align at the surface of the core fiber and deposit collagen types I and III. In summary, the study shows that PL-hASCs hydrogel coated suture threads represent a simple multi-compartment and multifunctional system, with PL hydrogel offering biofunctionality to guide the biological activities of encapsulated cells in addition to the replication of tissue-level mechanical support provided by the suture threads., Work developed under the framework of the Cooperation Agreement established with the Serviço de Imuno-Hemoterapia do Centro Hospitalar de S. João, EPE. The authors would like to thank to the Plastic Surgery Department of Hospital da Prelada (Porto, Portugal) for providing lipoaspirate tissue samples. Authors acknowledge the financial support from the ERC Grant CoG MagTendon nr 772817; and the Project NORTE-01-0145-FEDER-000021 (RCA pos-doc grant): “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marine-derived biomaterials and stem cells”, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); FCT–Fundação para a Ciência e a Tecnologia for the PhD grant of IC (PD/BD/128088/2016) and pos-doc grant of RMAD (SFRH/BPD/112459/2015); and HORIZON 2020 under the TEAMING Grant agreement No 739572 - The Discoveries CTR. R.A. was the recipient of a scholarship from the School of Engineering of the University of Bologna (Italy).

Ruxolitinib is the only commercially available JAK1/2 inhibitor approved for the treatment of myelofibrosis-related splenomegaly and symptoms. During treatment, as rare conditions, leukocytosis and/or thrombocytosis could develop and the management of these situations is not well established. We report here 53 myelofibrosis patients that received a combination of hydroxyurea and ruxolitinib because of uncontrolled myeloproliferation. Both drugs were administered outside clinical trials. At 48weeks, a significant reduction in leucocyte and platelet counts was observed (p= 0.02 and p= 0.04, respectively). Additionally, the spleen volume decreased from a median value of 10cm below the left costal margin (range, 0-10) to 6cm (range, 0-15). The rate of spleen response increased from 14% at the start of the combination to 45% after 48weeks. The safety profile of the combination was consistent with that observed with ruxolitinib single agent. These data require further confirmation in large cohorts of patients prospectively assessed.

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Supplemental Digital Content is available in the text., Objective— Cardiovascular disease, including coronary artery disease (CAD) and ischemic stroke, is the leading cause of death worldwide. This Mendelian randomization study uses genetic variants as instruments to investigate whether there is a causal effect of genetically determined platelet count on CAD and ischemic stroke risk. Approach and Results— A genome-wide association study of 166 066 subjects was used to identify instruments and genetic association estimates for platelet count. Genetic association estimates for CAD and ischemic stroke were obtained from genome-wide association studies, including 60 801 CAD cases and 123 504 controls, and 60 341 ischemic stroke cases and 454 450 controls, respectively. The inverse-variance weighted meta-analysis of ratio method Mendelian randomization estimates was the main method used to obtain estimates for the causal effect of genetically determined platelet count on risk of cardiovascular outcomes. We found no significant Mendelian randomization effect of genetically determined platelet count on risk of CAD (odds ratio of CAD per SD unit increase in genetically determined platelet count, 1.01; 95% CI, 0.98–1.04; P=0.60). However, higher genetically determined platelet count was causally associated with an increased risk of ischemic stroke (odds ratio, 1.07; 95% CI, 1.04–1.11; P

Objective— Cardiovascular disease, including coronary artery disease (CAD) and ischemic stroke, is the leading cause of death worldwide. This Mendelian randomization study uses genetic variants as instruments to investigate whether there is a causal effect of genetically determined platelet count on CAD and ischemic stroke risk. Approach and Results— A genome-wide association study of 166 066 subjects was used to identify instruments and genetic association estimates for platelet count. Genetic association estimates for CAD and ischemic stroke were obtained from genome-wide association studies, including 60 801 CAD cases and 123 504 controls, and 60 341 ischemic stroke cases and 454 450 controls, respectively. The inverse-variance weighted meta-analysis of ratio method Mendelian randomization estimates was the main method used to obtain estimates for the causal effect of genetically determined platelet count on risk of cardiovascular outcomes. We found no significant Mendelian randomization effect of genetically determined platelet count on risk of CAD (odds ratio of CAD per SD unit increase in genetically determined platelet count, 1.01; 95% CI, 0.98–1.04; P =0.60). However, higher genetically determined platelet count was causally associated with an increased risk of ischemic stroke (odds ratio, 1.07; 95% CI, 1.04–1.11; P −5 ), including all major ischemic stroke subtypes. Similar results were obtained in sensitivity analyses more robust to the inclusion of pleiotropic genetic variants. Conclusions— This Mendelian randomization study found evidence that higher genetically determined platelet count is causally associated with higher risk of ischemic stroke.

Introduction: Platelets have a central role in the tissue response to injury, in hemostasis and clot formation. They also release rapidly and in orchestrated order bioactive molecules, important for angiogenesis and for tissue regeneration. Non-transfusional clinical use of platelet-derived products, such as Platelet Rich Plasma (PRP), is based on their ability to maximize cellular regeneration in lesions that have repair difficulties. Objectives: This review addresses the characteristics and the potential clinical use of platelets and their derivatives and discusses the legislative framework of their use in the Brazilian context. Method: The databases of PubMed, Brazilian Virtual Health Library, electronic pages of Anvisa and the Brazilian Ministry of Health were consulted between September 2017 and January 2018. Results: PRP is a platelet-derived product that cannot be chemically defined, and its proposed clinical uses are not orthologous applications. Conclusions: We can thus consider that the applications of PRP are Advanced Cell Therapies. Therefore, it is mandatory to standardize protocols and establish quality control criteria - such as traceability, efficacy and pharmacovigilance - so that their use can be properly controlled by the competent regulatory organs, guaranteeing safety in their use. Introdução: As plaquetas têm um papel central no processo da resposta tecidual à injúria, atuando na hemostasia primária e na coagulação, e liberando de maneira coordenada as moléculas bioativas importantes para a angiogênese e para a regeneração tecidual. O uso clínico não transfusional de produtos derivados de plaquetas, como o Plasma Rico em Plaquetas (PRP), baseia-se na sua habilidade de maximizar o processo de regeneração celular, em lesões com dificuldades de reparo natural. Objetivo: Esta revisão aborda as características e potencialidades do uso clínico de plaquetas e seus derivados e discute seu arcabouço legislativo no contexto brasileiro. Método: Foram consultadas as bases de dados PubMed, Biblioteca Virtual em Saúde, páginas eletrônicas da Anvisa e do ministério da Saúde, entre setembro 2017 e janeiro de 2018. Resultado: O PRP é produto derivado de plaquetas que não pode ser quimicamente definido, e o seu uso clínico aqui discutido não é ortólogo. Conclusão: Dessa maneira, podemos considerar a aplicação do PRP como uma Terapia Celular Avançada, sendo fundamental padronizar protocolos, estabelecer critérios de controle de qualidade (rastreabilidade, eficácia e fármaco-vigilância), tornando seu uso devidamente controlado pelos órgãos competentes, com maior segurança na sua utilização.

Background: Over 32% of burned battlefield causalities develop trauma-induced hypoxic respiratory failure, also known as acute respiratory distress syndrome (ARDS). Recently, 9 out of 10 US combat soldiers’ survived life-threatening trauma-induced ARDS supported with extracorporeal membrane oxygenation (ECMO), a portable form of cardiopulmonary bypass. Unfortunately, the size, incidence of coagulation complications, and the need for systematic anticoagulation for traditional ECMO devices have prevented widespread use of this lifesaving technology. Therefore, a compact, mobile, ECMO system using minimal anticoagulation may be the solution to reduce ARDS in critically ill military and civilian patients. Methods: We conducted a prospective cohort laboratory investigation to evaluate the coagulation function in an ovine model of oleic acid induced ARDS supported with veno-venous ECMO. The experimental design approximated the time needed to transport from a battlefield setting to an advanced facility and compared bolus versus standard heparin anticoagulation therapy. Results: Comprehensive coagulation and hemostasis assays did not show any difference because of ECMO support over 10 h between the two groups but did show changes because of injury. Platelet count and function did decrease with support on ECMO, but there was no significant bleeding or clot formation during the entire experiment. Conclusions: A bolus heparin injection is sufficient to maintain ECMO support for up to 10 h in an ovine model of ARDS. With a reduced need for systematic anticoagulation, ECMO use for battlefield trauma could reduce significant morbidity and mortality from ventilator-induced lung injury and ARDS. Future studies will investigate the mechanisms and therapies to support patients for longer periods on ECMO without coagulation complications. Level of Evidence: V—therapeutic animal experiment.

SummaryBackground Histone deacetylases (HDACs) play a key role in signaling in many cell types. However, little is known about the participation of HDACs, particularly sirtuins (SIRTs), in platelet reactivity. Objective To investigate the role of HDACs in platelets, we examined the effects of SIRT inhibition on platelet function and protein acetylation in human platelets. Methods We used washed platelets obtained from healthy subjects. Cambinol (SIRT1 and SIRT2 inhibitor), AGK2 (specific SIRT2 inhibitor) and EX527 (specific SIRT1 inhibitor) were used as SIRT inhibitors. Platelets were stimulated with collagen, thrombin, or U46619, and platelet responses were determined according to optical aggregometry findings, dense granule release, and cytosolic calcium levels (Fura-2AM fluorescence). Protein acetylation and phosphorylation were assessed by immunoblotting. Results SIRT inhibition remarkably reduced platelet responses (aggregation, granule release, and cytosolic calcium level; P

Background: Serum levels of neutrophils, platelets, and lymphocytes have been recognized as factors related to poor prognosis for many solid tumors, including bladder cancer (BC). Objective: To evaluate the prognostic role of the combination of the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and lymphocyte/monocyte ratio (LMR) in patients with high-risk non–muscle-invasive urothelial BC (NIMBC). Design, setting, and participants: A total of 1151 NMIBC patients who underwent first transurethral resection of the bladder tumor (TURBT) at 13 academic institutions between January 1, 2002 and December 31, 2012 were included in this analysis. The median follow-up was 48 mo. Intervention: TURBT with intravesical chemotherapy or immunotherapy. Outcome measurements and statistical analysis: Multivariable Cox regression analysis was performed to identify factors predictive of recurrence, progression, cancer-specific mortality, and overall mortality. A systemic inflammatory marker (SIM) score was calculated based on cutoffs for NLR, PLR, and LMR. Results and limitations: The 48-mo recurrence-free survival was 80.8%, 47.35%, 20.67%, and 17.06% for patients with an SIM score of 0, 1, 2, and 3, respectively (p < 0.01, log-rank test) while the corresponding 48-mo progression free-survival was 92.0%, 75.67%, 72.85%, and 63.1% (p < 0.01, log-rank test). SIM scores of 1, 2, and 3 were associated with recurrence (hazard ratio [HR] 3.73, 7.06, and 7.88) and progression (HR 3.15, 4.41, and 5.83). Limitations include the lack of external validation and comparison to other clinical risk models. Conclusions: Patients with high-grade T1 stage NMIBC with high SIM scores have worse oncologic outcomes in terms of recurrence and progression. Further studies should be conducted to stratify patients according to SIM scores to identify individuals who might benefit from early cystectomy. Patient summary: In this study, we defined a risk score (the SIM score) based on the measurement of routine systemic inflammatory markers. This score can identify patients with high-grade bladder cancer not invading the muscular layer who are more likely to suffer from tumor recurrence and progression. Therefore, the score could be used to select patients who might benefit from early bladder removal. Patients with high-risk non–muscle-invasive bladder cancer (BC) experienced greater recurrence and progression according to systemic inflammatory markers. This score could be used to select patients who might benefit from early cystectomy. The availability of these biomarkers in routine clinical practice gives further relevance to identification of the prognostic role of immune cells in patients with BC. These results could be translated into clinical practice to stratify patients who might benefit from early cystectomy.

Introduction Platelets activation/aggregation with subsequent thrombus formation is the main event in the pathophysiology of acute coronary syndrome. Once activated, platelets show an extensive cytoskeleton rearrangement that leads to recruitment of additional platelets to finally cause haemostatic plug formation. Thus, the cytoskeleton plays a pivotal role in this phenomenon. Colchicine (COLC) is an anti-inflammatory drug proven to reduce major cardiovascular events in patients with coronary artery disease. The molecular mechanisms by which COLC exerts these protective effects remain partially still unknown. Since COLC causes disruption of tubulin, a component of cell cytoskeleton, we investigated whether this drug might interfere with platelet aggregation by acting on cytoskeleton rearrangement. Methods and results Platelets isolated from healthy volunteers were activated with Adenosine Diphosphate (ADP, 20 μM) Collagen (COLL, 60 μg/ml) and Thrombin Activating Receptor Peptide (TRAP 25 μM) with/without COLC 10 μM pretreatment. After stimulus, aggregation was measured by light aggregometry overtime. Microtubules structure was assessed by immunohistochemistry and key proteins involved in regulation of actin-filament assembly and contractility such as Myosin Phosphatase Targeting subunit (MYPT), LIM domain kinase 1(LIMK1) and cofilin were evaluated by Western Blot analysis. Colchicine pretreatment significantly blunted ADP/COLL/TRAP-induced platelet aggregation (up to 40%). COLC effects appeared mediated by microtubules depolymerization and cytoskeleton disarrangement associated to inactivation of MYPT and LIMK1 that finally interfered with cofilin activity. Conclusions Our data indicate that colchicine exerts anti-platelet effects in vitro via inhibition of key proteins involved in cytoskeleton rearrangement, suggesting that its beneficial cardiovascular properties may be due, at least in part, to an inhibitory effect of platelet activity.

Platelets (PLTs) deteriorate over time when stored within blood banks through a biological process known as PLT storage lesion (PSL). Here, we describe the refinement of the biochemical model of PLT metabolism, iAT-PLT-636, and its application to describe and investigate changes in metabolism during PLT storage. Changes in extracellular acetate and citrate were measured in buffy coat and apheresis PLT units over 10 days of storage in the PLT additive solution T-Sol. Metabolic network analysis of these data was performed alongside our prior metabolomics data to describe the metabolism of fresh (days 1–3), intermediate (days 4–6), and expired (days 7–10) PLTs. Changes in metabolism were studied by comparing metabolic model flux predictions of iAT-PLT-636 between stages and between collection methods. Extracellular acetate and glucose contribute most to central carbon metabolism in PLTs. The anticoagulant citrate is metabolized in apheresis-stored PLTs and is converted into aconitate and, to a lesser degree, malate. The consumption of nutrients changes during storage and reflects altered PLT activation profiles following their collection. Irrespective of the collection method, a slowdown in oxidative phosphorylation takes place, consistent with mitochondrial dysfunction during PSL. Finally, the main contributors to intracellular ammonium and NADPH are highlighted. Future optimization of flux through these pathways provides opportunities to address intracellular pH changes and reactive oxygen species, which are both of importance to PSL. The metabolic models provide descriptions of PLT metabolism at steady state and represent a platform for future PLT metabolic research.

Background Arachidonic acid metabolism by cyclooxygenase (COX) is a major pathway for blood platelets’ activation, which is associated with pro-thrombotic platelet activity and the production of pro-inflammatory mediators. Inhibition of COX activity is one of the major means of anti-platelet pharmacotherapy preventing arterial thrombosis and reducing the incidence of cardiovascular events. Recent studies have presented that a silymarin (standardized extract of Milk thistle (Silybum marianum)) can inhibit the COX pathway. Accordingly, the aim of our study was to determine the effects of three major flavonolignans (silybin, silychristin and silydianin) on COX pathway activity in blood platelets. Methods We determined the effect of flavonolignans on arachidonic acid induced blood platelet aggregation, COX pathway metabolites formation, as well as COX activity in platelets. Additionally, we analysed the potential mechanism of this interaction using the bioinformatic ligand docking method. Results We observed that tested compounds decrease the platelet aggregation level, both thromboxane A2 and malondialdehyde formation, as well as inhibit the COX activity. The strongest effect was observed for silychristin and silybin. In our in silico study we showed that silychristin and silybin have conformations which interact with the active COX site as competitive inhibitors, blocking the possibility of substrate binding. Conclusions The results obtained from this study clearly present the potential of flavonolignans as novel antiplatelet and anti-inflammatory agents.

The increasing availability of metabolomics data necessitates novel methods for deeper data analysis and interpretation. We present a flux balance analysis method that allows for the computation of dynamic intracellular metabolic changes at the cellular scale through integration of time-course absolute quantitative metabolomics. This approach, termed “unsteady-state flux balance analysis” (uFBA), is applied to four cellular systems: three dynamic and one steady-state as a negative control. uFBA and FBA predictions are contrasted, and uFBA is found to be more accurate in predicting dynamic metabolic flux states for red blood cells, platelets, and Saccharomyces cerevisiae. Notably, only uFBA predicts that stored red blood cells metabolize TCA intermediates to regenerate important cofactors, such as ATP, NADH, and NADPH. These pathway usage predictions were subsequently validated through 13C isotopic labeling and metabolic flux analysis in stored red blood cells. Utilizing time-course metabolomics data, uFBA provides an accurate method to predict metabolic physiology at the cellular scale for dynamic systems., This work was supported by the National Heart Lung and Blood Institute (R43HL123074 and R43HL127843), the European Research Council (232816), and the U.S. Department of Energy (DE-SC0008701)., Ritrýnt tímarit

Background: Several studies have demonstrated that platelet counts in Helicobacter pylori-positive patients with chronic idiopathic thrombocytopenic purpura improved significantly after successful eradication of the infection. However, depending of the geographical region of the study the results have been highly divergent. Objective: The purpose of this study was to evaluate the effect of H. pylori eradication therapy on platelet count in a cohort of chronic idiopathic thrombocytopenic purpura patients from northeastern Brazil. Method: H. pylori status was determined in 28 chronic idiopathic thrombocytopenic purpura patients using the rapid urease test and histology. H. pylori-positive patients received standard triple therapy for one week. The effect of the eradication therapy was evaluated using the 13C-urea breath test two to three months after treatment. Results: The prevalence of H. pylori infection was similar to that found in the general population. Twenty-two patients (78.5%) were H. pylori-positive. Fifteen were treated, 13 (86%) of whom successfully. At six months, 4/13 (30%) displayed increased platelet counts, which remained throughout follow-up (12 months). Platelet response was not associated to mean baseline platelet count, duration of chronic idiopathic thrombocytopenic purpura, gender, age, previous use of medication, or splenectomy. Conclusions: H. pylori eradication therapy showed relatively low platelet recovery rates, comparable with previous studies from southeastern Brazil. The effect of H. pylori eradication on platelet counts remained after one year of follow-up suggesting that treating H. pylori infection might be worthwhile in a subset of chronic idiopathic thrombocytopenic purpura patients. Keywords: Helicobacter pylori eradication, Blood platelet, Idiopathic thrombocytopenic purpura

Background Hepatocellular carcinoma (HCC) is a heterogeneous disease with both tumor and liver factors being involved. Aims To investigate HCC clinical phenotypes and factors related to HCC size. Methods Prospectively-collected HCC patients' data from a large Italian database were arranged according to the maximum tumor diameter (MTD) and divided into tumor size terciles, which were then compared in terms of several common clinical parameters and patients' survival. Results An higer MTD tercile was significantly associated with increased blood alpha-fetoprotein (AFP), gamma-glutamyl transpeptidase (GGTP), and platelet levels. Patients with higher platelet levels had larger tumors and higher GGTP levels, with lower bilirubin levels. However, patients with the highest AFP levels had larger tumors and higher bilirubin levels, reflecting an aggressive biology. AFP correlation analysis revealed the existence of 2 different groups of patients: those with higher and with lower AFP levels, each with different patient and tumor characteristics. The Cox proportional-hazard model showed that a higher risk of death was correlated with GGTP and bilirubin levels, tumor size and number, and portal vein thrombosis (PVT), but not with AFP or platelet levels. Conclusions An increased tumor size was associated with increased blood platelet counts, AFP and GGTP levels. Platelet and AFP levels were important indicators of tumor size, but not of survival.

ObjectiveTo analyze the changes in platelet parameters and their influential factors in cirrhotic patients with hepatocellular carcinoma (HCC). MethodsThe clinical data of 602 cirrhotic patients with HCC who were admitted to the First Hospital of Jilin University from January 2011 to December 2012, as well as 200 cirrhotic patients hospitalized during the same period, were collected. Statistical analysis was performed using SPSS 19.0. Normally distributed continuous data were expressed as mean ± standard deviation; comparison between two groups was made by t test, and comparison between multiple groups was made by analysis of variance. Non-normally distributed data were expressed as median and interquartile range (P25-P75); comparison between groups was made by rank sum test. ResultsCompared with the cirrhotic group, the HCC group had significantly higher platelet count (PLT) and plateletcrit (PCT) (t=5.019, P=0000; t=5.017, P=0.000) and a significantly lower mean platelet volume (MPV)/PLT (t=5.877, P=0.000); there were no significant differences in MPV and platelet distribution width between the two groups (t=-0.942, P=0.347; t=-1.040, P=0.298). The receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.636 for PLT, 0.633 for PCT, and 0.639 for MPV/PLT in the diagnosis of HCC in cirrhotic patients. Decreases in PLT and PCT were closely related to hepatitis C virus (HCV) infection. Patients with Child-Pugh class A cirrhosis had significantly higher PLT and PCT than those with Child-Pugh class B and C cirrhosis (P＜0.01); patients with a maximum tumor diameter of ≥5 cm had significantly higher PLT and PCT than those with maximum tumor diameters of 2-5 cm and ≤2 cm (P＜0.01). Patients with Child-Pugh class A cirrhosis had a significantly lower MPV/PLT than those with Child-Pugh class B and C cirrhosis (P＜0.01); patients with a maximum tumor diameter of ≥5 cm had a significantly lower MPV/PLT than those with maximum tumor diameters of 2-5 cm and ≤2 cm (P＜0.01). ConclusionPLT, PCT, and MPV/PLT can be used in the auxiliary diagnosis of HCC in cirrhotic patients, which are related to HCV, Child-Pugh classification, and tumor size.

Glanzmann's thrombasthenia (GT) is a rare congenital bleeding disorder associated with decreased platelet aggregation due to qualitative/quantitative deficiencies of the fibrinogen receptor. Severe bleeding episodes and perioperative bleeding are typically managed with platelet transfusions, although patients can develop anti-platelet antibodies or experience clinical refractoriness. The GT Registry (GTR) was established to collect efficacy/safety data on hemostatic treatments for GT, including recombinant factor VIIa (rFVIIa). At the request of the United States Food and Drug Administration, three hematology experts evaluated platelet refractoriness, antibody status, and rFVIIa efficacy data on a case-by-case basis to support a potential indication for rFVIIa in GT. Adjudication included 195 patients with 810 events (619 severe bleeding episodes, 192 surgeries), and a consensus algorithm was developed to describe adjudicators' coding of refractoriness and antibody status based on treatment patterns over time. Most rFVIIa-treated events were in patients without refractoriness or antibodies. Adjudicators rated most rFVIIa-treated bleeding episodes as successful (251/266, 94.4%; rFVIIa only, 101/109, 92.7%; rFVIIa ± platelets ± other agents, 150/157, 95.5%); efficacy was consistent in patients with platelet refractoriness ± antibodies (75/79, 94.9%), antibodies only (10/10, 100.0%), and neither/unknown (166/177, 93.8%). Adjudicators also rated most rFVIIa-treated surgeries as successful (159/160, 99.4%; rFVIIa only, 65/66, 98.5%; rFVIIa ± platelets ± other agents, 94/94, 100.0%); efficacy was consistent in patients with platelet refractoriness ± antibodies (69/70, 98.6%), antibodies only (24/24, 100.0%), and neither/unknown (66/66, 100.0%). Unblinding the adjudicators to investigator efficacy ratings changed few assessments. Doses of rFVIIa were narrowly distributed, regardless of other hemostatic agents used. This article is protected by copyright. All rights reserved.

Purpose of Review: This review aims to summarize and discuss safety and effectiveness of the long-term use of ticagrelor in patients with coronary artery disease (CAD). Recent Findings: Ticagrelor is an orally administered, direct, and reversible inhibitor of the P2Y12-platelet receptor. Long-term use of ticagrelor in patients with previous myocardial infarction (MI) has been investigated in the PEGASUS-TIMI-54 trial. Overall, 21,162 patients with a spontaneous MI 1 to 3 years before randomization were randomly assigned to ticagrelor 90 mg bid, ticagrelor 60 mg bid, or placebo. Compared with placebo, both doses of ticagrelor showed that they were capable of significantly reducing the primary efficacy endpoint, although with a significant increase in TIMI major bleeding. Intracranial hemorrhage or fatal bleeding did not differ across groups. Summary: These findings establish clear benefit of DAPT extension with ticagrelor beyond 1 year of treatment, which comes with a tradeoff of clinically meaningful bleeding. Altogether, current evidence suggests that the duration of DAPT remains a patient-by-patient decision based on thrombotic and bleeding risk profiles.

AIM To investigate the prognostic value of the radiological response after transarterial chemoembolization (TACE) and inflammatory markers in patients affected by hepatocellular carcinoma (HCC) awaiting liver transplantation (LT). METHODS We retrospectively evaluated the preoperative predictors of HCC recurrence in 70 patients treated with conventional (n = 16) or doxorubicin-eluting bead TACE (n = 54) before LT. The patient and tumour characteristics, including the static and dynamic alpha-fetoprotein, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio (PLR) measurements, were recorded. Treatment response was classified according to the modified Response Evaluation Criteria in Solid Tumours (mRECIST) and the European Association for the Study of the Liver (EASL) criteria as complete response (CR), partial response (PR), stable disease or progressive disease. After examination of the explanted livers, histological necrosis was classified as complete (100% of the cumulative tumour area), partial (50%-99%) or minimal (< 50%) and was correlated with the preoperative radiological findings. RESULTS According to the pre-TACE radiological evaluation, 22/70 (31.4%) and 12/70 (17.1%) patients were beyond Milan and University of San Francisco (UCSF) criteria, respectively. After TACE procedures, the objective response (CR + PR) rates were 71.4% and 70.0% according to mRECIST and EASL criteria, respectively. The agreement between the two guidelines in defining the radiological response was rated as very good both for the overall and target lesion response (weighted k-value: 0.98 and 0.93, respectively). Complete and partial histological necrosis were achieved in 14/70 (20.0%) and 28/70 (40.0%) patients, respectively. Using histopathology as the reference standard, mRECIST criteria correctly classified necrosis in 72.9% (51/70) of patients and EASL criteria in 68.6% (48/70) of cases. The mRECIST non-response to TACE [Exp(b) = 9.2, p = 0.012], exceeding UCSF criteria before TACE [Exp(b) = 4.7, p = 0.033] and a preoperative PLR > 150 [Exp(b) = 5.9, p = 0.046] were independent predictors of tumour recurrence. CONCLUSION The radiological response and inflammatory markers are predictive of tumour recurrence and allow the proper selection of TACE-treated candidates for LT.

Objective— Platelet- and fibrin-dependent thrombus formation is regulated by blood flow and exposure of collagen and tissue factor. However, interactions between these blood-borne and vascular components are not well understood. Approach and Results— Here, we developed a method to assess whole-blood thrombus formation on microspots with defined amounts of collagen and tissue factor, allowing determination of the mechanical properties and intrathrombus composition. Confining the collagen content resulted in diminished platelet deposition and fibrin formation at high shear flow conditions, but this effect was compensated by a larger thrombus size and increased accumulation of fibrin in the luminal regions of the thrombi at the expense of the base regions. These thrombi were more dependent on tissue factor–triggered thrombin generation. Microforce nanoindentation analysis revealed a significantly increased microelasticity of thrombi with luminal-oriented fibrin. At a low shear rate, fibrin fibers tended to luminally cover the thrombi, again resulting in a higher microelasticity. Studies with blood from patients with distinct hemostatic insufficiencies indicated an impairment in the formation of a platelet–fibrin thrombus in the cases of dilutional coagulopathy, thrombocytopenia, Scott syndrome, and hemophilia B. Conclusions— Taken together, our data indicate that (1) thrombin increases the platelet thrombus volume; (2) tissue factor drives the formation of fibrin outside of the platelet thrombus; (3) limitation of platelet adhesion redirects fibrin from bottom to top of the thrombus; (4) a lower shear rate promotes thrombus coverage with fibrin; (5) the fibrin distribution pattern determines thrombus microelasticity; and (6) the thrombus-forming process is reduced in patients with diverse hemostatic defects.

5-Lipoxygenase (5-LO) catalyzes the first two steps in leukotriene (LT) biosynthesis. Because LTs play pivotal roles in allergy and inflammation, 5-LO represents a valuable target for anti-inflammatory drugs. Here, we investigated the molecular mechanism, the pharmacological profile, and the in vivo effectiveness of the novel 1,2-benzoquinone-featured 5-LO inhibitor RF-22c. Compound RF-22c potently inhibited 5-LO product synthesis in neutrophils and monocytes (IC50 ≥ 22 nM) and in cell-free assays (IC50 ≥ 140 nM) without affecting 12/15-LOs, cyclooxygenase (COX)-1/2, or arachidonic acid release, in a specific and reversible manner, supported by molecular docking data. Antioxidant or iron-chelating properties were not evident for RF-22c and 5-LO-regulatory cofactors like Ca2+ mobilization, ERK-1/2 activation, and 5-LO nuclear membrane translocation and interaction with 5-LO-activating protein (FLAP) were unaffected. RF-22c (0.1 mg/kg; i.p.) impaired (I) bronchoconstriction in ovalbumin-sensitized mice challenged with acetylcholine, (II) exudate formation in carrageenan-induced paw edema, and (III) zymosan-induced leukocyte infiltration in air pouches. Taken together, RF-22c is a highly selective and potent 5-LO inhibitor in intact human leukocytes with pronounced effectiveness in different models of inflammation that warrants further preclinical analysis of this agent as anti-inflammatory drug.

Platelet concentrates for surgical use are tools of regenerative medicine designed for the local release of platelet growth factors into a surgical or wounded site, in order to stimulate tissue healing or regeneration. Leukocyte content and fibrin architecture are 2 key characteristics of all platelet concentrates and allow to classify these technologies in 4 families, but very little is known about the impact of these 2 parameters on the intrinsic biology of these products. In this demonstration, we highlight some outstanding differences in the growth factor and matrix protein release between 2 families of platelet concentrate: Pure Platelet-Rich Plasma (P-PRP, here the Anitua's PRGF - Preparation Rich in Growth Factors - technique) and Leukocyte- and Platelet-Rich Fibrin (L-PRF, here the Choukroun's method). These 2 families are the extreme opposites in terms of fibrin architecture and leukocyte content. The slow release of 3 key growth factors (Transforming Growth Factor β1 (TGFβ1), Platelet-Derived Growth Factor AB (PDGF-AB) and Vascular Endothelial Growth Factor (VEGF)) and matrix proteins (fibronectin, vitronectin and thrombospondin-1) from the L-PRF and P-PRP gel membranes in culture medium is described and discussed. During 7 days, the L-PRF membranes slowly release significantly larger amounts of all these molecules than the P-PRP gel membranes, and the 2 products display different release patterns. In both platelet concentrates, vitronectin is the sole molecule to be released almost completely after only 4 hours, suggesting that this molecule is not trapped in the fibrin matrix and not produced by the leukocytes. Moreover the P-PRP gel membranes completely dissolve in the culture medium after less than 5 days only, while the L-PRF membranes are still intact after 7 days. This simple demonstration shows that the polymerization and final architecture of the fibrin matrix considerably influence the strength and the growth factor trapping/release potential of the membrane. It also suggests that the leukocyte populations have a strong influence on the release of some growth factors, particularly TGFβ1. Finally, the various platelet concentrates present very different biological characteristics, and an accurate definition and characterization of the different families of product is a key issue for a better understanding and comparison of the reported clinical effects of these surgical adjuvants.

OBJECTIVE: A novel mechanism of platelet destruction involving the CD47/ signal regulatory protein-α (SIRPα) system has recently been suggested in a mouse model of immune thrombocytopenia (ITP). The CD47 molecule serves as ligand for SIRPα receptor and as receptor for thrombospondin acting as antagonistic to phagocyte activity and a regulator of apoptosis, respectively. In this study, we evaluated if the CD47/SIRPα axis may be involved in the apoptosis and clearance of platelets in human ITP. MATERIALS AND METHODS: Using flow cytometry, we characterized whether expression of CD47 on fresh and in vitro-aged platelets- and of SIRPα receptor on CD14-derived dendritic cells (DCs), macrophages, circulating DCs, and monocytes is reduced is ITP; whether the in vitro platelet phagocytic capacity of CD14-derived DCs and macrophages is differentially modulated in the presence or absence of antibodies against CD47 and SIRPα in ITP; and whether platelets are more susceptible to the CD47-induced death signal in ITP. RESULTS: We demonstrated that low platelet count in ITP is not due to increased phagocytosis associated with decreased expression of CD47 on the platelet surface and, despite reduced SIRPα expression, blockage of SIRPα on immature CD14-derived DCs or CD47 on platelets by specific antibodies failed to modify platelet uptake/phagocytosis of DCs. In contrast, targeting platelet CD47 with specific antibody significantly increases platelet phagocytosis of CD14-derived macrophages, and platelets are not healthy because they show increased apoptosis and are resistant to CD47-induced death signal. CONCLUSIONS: Our results demonstrate that the CD47 pathway in ITP patients abnormally modulates platelet homeostasis.

Adequate platelet inhibition is mandatory in patients undergoing percutaneous coronary intervention in order to prevent recurrent thrombotic events. Dual antiplatelet therapy with aspirin and thienopyridine (e.g., clopidogrel) is the treatment of choice in this setting, providing clear clinical benefit in most of the patients. However, a wide interindividual variability exists in the response to antiplatelet drugs and several factors may contribute to determine fluctuation in platelet reactivity, even within the individual patient. Several methodologies and devices have been developed to monitor individual response to antiplatelet treatment, assessing different pathways of platelet activation and aggregation. Studies performed with the use of these methodologies have clearly demonstrated that patients with high post-treatment residual platelet reactivity present a higher risk of ischemic events both at short (during or soon after percutaneous coronary intervention) and long term. In these patients, more aggressive antithrombotic strategies, based on the results of platelet function tests, may be beneficial in order to reduce ischemic complications after percutaneous coronary intervention. © 2010 Future Medicine Ltd.

Objectives: We sought to evaluate the influence of platelet reactivity after clopidogrel, as assessed by the VerifyNow point-of-care assay (Accumetrics, San Diego, California), on myonecrosis in low-to-intermediate risk patients undergoing percutaneous coronary intervention (PCI). Background: Inadequate platelet inhibition at the time of PCI is associated with a higher risk of recurrent ischemic events. Methods: A total of 250 consecutive biomarker-negative patients treated with clopidogrel and undergoing elective PCI were enrolled. Cardiac biomarkers (creatine kinase-myocardial band and troponin I) were measured before and 8 and 24 h after intervention. Platelet reactivity after clopidogrel was assessed immediately before PCI by the VerifyNow P2Y12 point-of-care assay. High platelet reactivity (HPR) after clopidogrel was defined as a platelet reaction unit value ≥240. Results: Patients with HPR (31% of the overall population) showed more frequent myonecrosis, with statistical significance with regard to creatine kinase-myocardial band elevation (35% vs. 20%; p = 0.011), and by trend with regard to troponin-I elevation (47% vs. 35%; p = 0.059). Incidence of periprocedural myocardial infarction was higher in patients with HPR, both by creatine kinase-myocardial band (13% vs. 4%; p = 0.011) and troponin-I definition (32% vs. 19%; p = 0.019). By multivariable analysis, HPR was an independent predictor of periprocedural myocardial infarction. Conclusions: Easily assessed by a point-of-care assay, HPR after clopidogrel is a frequent finding and is associated with increased risk of myonecrosis in low-to-intermediate risk patients undergoing planned PCI. © 2010 American College of Cardiology Foundation.

Platelet reactivity is greater in patients with stable angina and with more extensive peripheral vascular atherosclerosis. We sought to evaluate whether impaired peripheral microcirculatory endothelial function might correlate with platelet reactivity after clopidogrel and therefore predispose to an unfavorable outcome after percutaneous coronary intervention (PCI). In 52 consecutive patients with stable angina undergoing elective PCI, endothelial function was assessed by (1) endothelial peripheral arterial tonometry (measuring the "Endoscore"); (2) the von Willebrandt factor antigen level and ristocetin co-factor activity. Basal platelet reactivity was assessed by soluble P-selectin. Patients then received a 600-mg clopidogrel loading dose ≥12 hours before PCI. A blood sample was withdrawn 12 hours later, but before PCI, to assess platelet reactivity using the P2Y12 reaction unit and percentage of P2Y12 inhibition with the point-of-care VerifyNow P2Y12 assay. Troponin T was assessed 24 hours after PCI. The Endoscore inversely correlated with von Willebrandt factor antigen activity (r = -0.52, p = 0.0001) and soluble P-selectin concentration (r = -0.36, p = 0.021), suggesting greater platelet reactivity with increased impaired endothelial function. After clopidogrel, the Endoscore correlated directly with the percentage of P2Y12 inhibition (r = 0.36, p = 0.009) and inversely with the P2Y12 reaction unit (r = -0.41, p = 0.002), suggesting greater residual platelet reactivity with more impaired endothelial function. The average Endoscore was significantly lower in patients with troponin T elevation (troponin positive group 0.267 ± 0.091) than in patients without troponin T elevation (troponin negative group 0.508 ± 0.041, p = 0.015 vs troponin positive). In conclusion, an impaired endothelial response before clopidogrel was associated with greater platelet reactivity after clopidogrel. This link might explain the unfavorable PCI outcomes in patients with more severe endothelial impairment. © 2010 Elsevier Inc. All rights reserved.