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BACKGROUND: Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH. HYPOTHESIS: Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation. ANIMALS: Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH. METHODS: Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA. RESULTS: Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups. CONCLUSION AND CLINICAL IMPORTANCE: Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

Introduction: Thrombotic and haemorrhagic complications have been reported following transcatheter aortic valve implantation (TAVI). However, few reports have studied perioperative changes in coagulation and platelet function after TAVI. Furthermore, there are no clear guidelines for antithrombotic therapy. This study aimed to examine the perioperative changes in coagulation and platelet contribution to clot strength after TAVI using thromboelastography (TEG 6s; Hemonetics). Methods: This prospective observational study included 15 patients scheduled to undergo TAVI for severe aortic stenosis. TEG 6s global haemostasis was used to record three measurements: on the day of surgery (immediately before the operation) and postoperative days 1 and 3. The reaction time R to thrombosis; K and α, which represent the rate of thrombosis; and the maximum amplitude (MA) were measured from the kaolin thromboelastography (TEG) curves. The coagulation index (CI) was calculated from the measurement results to assess thrombotic tendency. In addition, MA was converted to elastic clot strength, and platelet function was assessed by the difference, Gp, in elastic strength depending on platelet activation. Results: R and K decreased, and α tended to increase in kaolin TEG on days 1 and 3 after TAVI, indicating elevated coagulation function compared with the preoperative period, but MA and CI did not show significant changes. Gp decreased significantly on days 1 and 3, suggesting a decrease in the platelet contribution to clot strength. Conclusions: Compared with the preoperative period, coagulation tended to increase, and platelet contribution to clot strength decreased from days 1 to 3 after TAVI. [ABSTRACT FROM AUTHOR]

Platelets are the smallest blood cells, numbering 150 to 350 × 10 9 /L in healthy individuals. The ability of activated platelets to adhere to an injured vessel wall and form aggregates was first described in the 19th century. Besides their long-established roles in thrombosis and hemostasis, platelets are increasingly recognized as pivotal players in numerous other pathophysiological processes including inflammation and atherogenesis, antimicrobial host defense, and tumor growth and metastasis. Consequently, profound knowledge of platelet structure and function is becoming more important in research and in many fields of modern medicine. This review provides an overview of platelet physiology focusing particularly on the structure, granules, surface glycoproteins, and activation pathways of platelets. [ABSTRACT FROM AUTHOR]

Increased platelet activity is a risk factor of thrombotic events in cardiovascular patients. We studied the relationship between platelet function, platelet size, and the content of reticulated platelets (RP) in patients with coronary heart disease (CHD, n = 55) and acute coronary syndrome (ACS, n = 95) receiving acetylsalicylic acid + clopidogrel or ticagrelor, respectively. The control group consisted of patients with risk factors for CHD, but with no CHD/ACS and free of antiplatelet drugs (n = 66). Platelet function was evaluated by the exposure of activated glycoprotein (GP) IIb-IIIa and P-selectin. In the control group, platelets were activated by TRAP (Thrombin Receptor Activating Peptide) 10 µM, and ADP 20, 5, 2.5 µM, and in the CHD/ACS groups, by TRAP 10 µM, and ADP 20 5 µM (±epinephrine 20 µM). Platelet size was assessed by the mean volume, % large forms, and forward scattering. RP were stained by thiazole orange. In the control group, activated GP IIb-IIIa and P-selectin correlated with platelet size and RP content after platelet activation by all agonists. Despite the decrease in platelet activity by antiplatelet drugs, most correlations (primarily for activated GP IIb-IIIa) were preserved in the CHD/ACS patients. In conclusion, increased platelet size and RP content are associated with increased platelet activity and the reduced efficacy of antiplatelet therapy. [ABSTRACT FROM AUTHOR]

Antiplatelet therapy is integral to reduce the risk of future ischemic events following acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI); this aim must be balanced by limiting the risk of bleeding. Women with ACS or undergoing PCI have distinct platelet physiology, vascular anatomy, and clinical profiles that can influence the selection of an appropriate regimen. There are procedural techniques that can enhance safety in women. The poor inclusion of women in ACS and PCI trials limits our understanding of the ideal antiplatelet regimen in women, and future studies must find ways to increase the participation of female patients. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Renal replacement therapy (RRT) may affect coagulation and platelet function in critically ill patients. However, the mechanism and the difference in the impact on coagulation between intermittent hemodialysis (iHD) and continuous renal replacement therapy (CRRT) remains unclear. This study aimed to investigate and compare the impact of iHD and CRRT on coagulation and platelet function.Critically ill patients undergoing RRT were classified into the iHD group or the CRRT group. After the first blood sampling, patients underwent either a single session of hemodialysis or 48 h of CRRT, then a second blood sample was taken. Rotational thromboelastometry (ROTEM), platelet aggregometry and conventional coagulation tests were performed. The primary outcome was a change in extrinsically activated ROTEM (EXTEM) clotting time (CT).60 dialysis sessions from 56 patients were finally included, with 30 dialysis sessions per group. EXTEM CT was prolonged significantly after dialysis in the iHD group (90 [74, 128] vs. 74 [61, 91], p < 0.001), but did not change in the CRRT group (94.4 ± 29.4 vs. 91.6 ± 22.9, p = 0.986). The platelet aggregation did not change after both iHD and CRRT. A change in EXTEM CT was significantly greater in the iHD group compared to the CRRT group (p = 0.006). The difference in the incidence of bleeding events was insignificant between the two groups (p = 0.301).EXTEM CT was significantly prolonged after iHD, but this change was not shown after CRRT. Platelet function was not affected by both dialysis modalities. [ABSTRACT FROM AUTHOR]

The influence of chimeric antigen receptor T (CAR-T) cell therapy on platelet function in relapsed/refractory (R/R) multiple myeloma (MM) has not been thoroughly investigated. Our cohort comprised fifty MM patients treated with CAR-T cells. The mean platelet closure time (PCT) induced by collagen/adenosine diphosphate (CADP) in peripheral blood was significantly prolonged before lymphodepletion (195.24 ± 11.740 s) and notably reduced post-CAR-T cell therapy (128.02 ± 5.60 s), with a statistically significant improvement (67.22, 95% CI 46.91–87.53, P < 0.001). This post-treatment PCT was not significantly different from that of healthy controls (10.64, 95% CI 1.11–22.40, P > 0.05). Furthermore, a pronounced enhancement in PCT was observed in patients with a response greater than partial remission (PR) following CAR-T cell infusion compared to pre-treatment values (P < 0.001). An extended PCT was also associated with a less favorable remission status. In patients with cytokine release syndrome (CRS) grades 0–2, those with a PCT over 240.5 s exhibited a shorter progression-free survival (PFS), with median PFS times of 10.2 months for the PCT > 240.5 s group versus 22.0 months for the PCT ≤ 240.5 s group. Multivariate analysis revealed that a PCT value exceeding 240.5 s is an independent prognostic factor for overall survival (OS) in R/R MM patients after CAR-T cell therapy. The study demonstrates that CAR-T cell therapy enhances platelet function in R/R MM patients, and PCT emerges as a potential prognostic biomarker for the efficacy of CAR-T cell therapy. [ABSTRACT FROM AUTHOR]

Introduction Thirdhand smoke (THS) is associated with many public health and disease concerns, such as respiratory illness, cancer, lipidemia, and cardiovascular disease (CVD). We have previously shown that a moderate to long-term exposure to THS increases the risk of thrombosis. However, whether short-term exposure to THS would produce any effects remains to be discovered. Therefore, this study investigated the impact of 1-month THS exposure on platelet function, in vivo and in vitro, and on cytokine response, in a sex-dependent manner. Aims and Methods Secondhand smoke or clean air (CA) exposed upholstery materials for 1 week were kept in cages housed with 5–6 mice, and the procedure was repeated for 4 weeks. These THS-exposed mice were evaluated for thrombogenesis and platelet function assays. In addition, cytokines expression was evaluated from pooled serum. Results Compared to the CA group, THS exposure significantly shortened the tail bleeding time and carotid artery thrombus formation. Moreover, the female mice appeared more sensitive to THS exposure than males. Furthermore, platelet aggregation, dense granule secretion, and P-selectin activation markers were significantly elevated due to THS exposure. In addition, high-throughput screening showed at least 30 cytokines differentially modulated by THS in females relative to 26 in male mice. Conclusions Collectively, these results demonstrate that 1 month of THS exposure represents a high health risk, in part, by triggering a prothrombotic phenotype that appears to be more significant in females, who are at a much higher risk for occlusive CVD. Additionally, changes in cytokine levels mediate some of the THS-induced occlusive effects. Implications This study revealed that THS exposure for 1 month is detrimental to the cardiovascular health of both sexes; however, females could be more aggressively affected than males. In addition, interleukins and chemokines could be critical factors for initiating prothrombotic activity due to THS exposure. [ABSTRACT FROM AUTHOR]

Abstract Background Thromboelastography (TEG) is a widely utilized clinical testing method for real‐time monitoring of platelet function and the thrombosis process. Lipid metabolism disorders are crucial risk factors for thrombosis. The lipid metabolism characteristics of hamsters resemble those of humans more closely than mice and rats, and their relatively large blood volume makes them suitable for studying the mechanisms of thrombosis related to plasma lipid mechanisms. Whole blood samples from golden Syrian hamsters and healthy humans were obtained following standard clinical procedures. TEG was employed to evaluate coagulation factor function, fibrinogen (Fib) function, platelet function, and the fibrinolytic system. Methods The whole blood from hamster or healthy human was isolated following the clinical procedure, and TEG was employed to evaluate the coagulation factor function, Fib function, platelet function, and fibrinolytic system. Coagulation analysis used ACLTOP750 automatic coagulation analysis pipeline. Blood routine testing used XN‐2000 automatic blood analyzer. Results TEG parameters revealed that hamsters exhibited stronger coagulation factor function than humans (reaction time [R], p = 0.0117), with stronger Fib function (alpha angle, p

Objective To investigate the feasibility of leucocyte-reduced pooled platelet concentrates from whole blood stored at 4℃, and provide theoretical basis for the components preparation. Methods The collected 400 mL ACD-B anticoagulant whole blood was randomly divided into two groups, stored at 4℃ and room temperature. The buffy coat was prepared within 6 hours and store at 22℃ until next day to prepare leucocyte-reduced pooled platelet concentrates. Platelet samples on day 1, 3, 5 and 7 were taken for the blood cell count and related parameter detection. The pH, glucose and lactic acid content were determined to reflect the metabolic status, and the thromboelastography, platelet aggregation rate and PAC-1 and CD62P expression were determined to reflect the function and activation of platelets. The difference in platelets between two groups were analyzed. Results With the extension of storage time, the count of leucocyte-reduced pooled platelet concentrates decreased gradually, but the platelets distribution width (PDW), mean platelet volume (MPV) and platelet-larger cell ratio (P-LCR) increased gradually in two groups, with no statistical significance (P>0.05).The pH and glucose contents in two groups gradually decreased, but the lactic acid content gradually increased, with no significant difference (P>0.05). The thrombelastogram showed MA value that reflecting platelet function has no significant change during the storage, and there was no significant difference between the two groups (P>0.05). The aggregation rates decreased while the expression of PAC-1 and CD62P increased gradually with the prolongation of preservation time, with no significant difference between the two groups (P>0.05). Conclusion There is no significant difference in platelet count, function and activation between whole blood stored at 4℃ and at room temperature within 6 hours. Whole blood stored at 4℃ within 6 hours can be considered as the raw material for leucocyte-reduced pooled platelet concentrates.

Abstract Background Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH. Hypothesis Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet‐leukocyte, and platelet‐neutrophil aggregate formation. Animals Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH. Methods Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3‐view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet‐leukocyte/platelet‐neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA. Results Unstimulated platelets from dogs with MMVD and PH expressed more surface P‐selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet‐leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet‐neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups. Conclusion and Clinical Importance Platelet hyperresponsiveness and increased platelet‐neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

Objective To investigate the effects of polybutylene terephthalate(PBT) grafted with various monomers, such as acrylic acid(AA), acrylamide(AM), sodium styrene sulfonate(SSS), AA+ AM and AA+ SSS on platelet adhesion and function. Methods The AA, AM, SSS, AA+ AM, and AA+ SSS were grafted onto the surface of PBT by γ-ray irradiation, and the grafted PBT was characterized by fourier transform infrared spectrometry(FTIR) and wetting time. Platelet activation and aggregation of different monomers grafted with PBT were observed by scanning electron microscopy(SEM). Platelet concentration, maximum aggregation ability, positive expression rate of CD62p and hypotonic shock rate(HSR)of PBT grafted with different monomers were tested to study their effect on platelet adhesion and function. Results The characteristic absorption peaks of AA, AM and SSS appeared in FTIR, and the hydrophilicity of the grafted material was improved obviously, indicating that the monomer was grafted successfully. The results of SEM showed that the degree of platelet activation and aggregation caused by the original PBT was significantly higher than that of modified ones. Compared with the original platelets, the platelet concentration of PBT was(533.00±4.58 vs 672.00±3.61)×109/L, the maximum platelet aggregation rate was(48.80±0.96 vs 58.60±1.37)%, the positive expression rate of CD62p was(45.35±0.58 vs 39.90±0.52)%, and the platelet HSR was(48.74±0.46 vs 51.86±0.93)%(P

Maternal age has significantly increased among Chinese women, thereby posing risk of pregnancy-related complications. Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality, and coagulation analysis in conjunction with clinical signs and symptoms are generally used for its diagnosis with limited efficacy. Sonoclot coagulation analyzer is effective in assessing coagulation function used during cerebral surgery and cardiovascular surgery. However, its use has not been explored in preeclampsia. Here, we investigated the potential use of Sonoclot in diagnosing preeclampsia in obstetrics cases. Subjects meeting the screening criteria were divided either into a test group or a control group, according to whether they were preeclamptic or not. We recorded the Sonoclot-derived coagulation and the routine coagulation parameters including platelet function (PF), activated clotting time (ACT) and clot rate (CR), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), and platelet count. Regression analysis was done on the relevant parameters to assess the feasibility of Sonoclot analyzer in preeclampsia diagnosis. In parallel, changes in preeclampsia lncRNAs was also evaluated. Significant differences were recorded in PT and ACT between the two groups. In the monovariant logistic regression, PT and ACT appeared to be reliable predictor variables. In the multinomial logistic regression, a total of five regression steps were performed with decreasing AIC values. The K-fold cross validation resulted in an accuracy rate (ACC) of 77.5%, a false positive rate of 16.4%, and a false negative rate of 33.2%. lncRNAs ANRIL and HOXD-AS1 were found deregulated. Our findings indicate that Sonoclot may be useful for diagnosis of preeclampsia in obstetrics.

BACKGROUND: Cardiovascular disease (CVD) is a global health challenge. Various studies have shown that genetic and environmental factors play roles in the development and progression of CVD. Small non-coding RNAs, namely microRNAs (miRs), regulate gene expression and have key roles in essential cellular processes such as apoptosis, cell cycle, differentiation, and proliferation. Currently, clinical studies highlight the critical role of platelets and miRs in coronary thrombosis, atherosclerosis, and CVD. METHODS: Using search engines such as PubMed and Scopus, articles studying platelet miRs and their effects on atherosclerosis and cardiovascular disease were reviewed. RESULTS: This article presents a comprehensive analysis of the association of platelet- related miRs as prognostic, diagnostic, and therapeutic biomarkers with the pathogenesis of atherosclerosis and cardiovascular disease. CONCLUSION: Taken together, data show that platelet-related miRs not only play important roles in the initial development of atherosclerosis and cardiovascular disease (CVD), but they are also considered prognostic and diagnostic biomarkers in CVD. [ABSTRACT FROM AUTHOR]

Objective To investigate the efficacy of indobuprofen combined with nicodil for the treatment of acute coronary syndromes (ACS) and the effects of percutaneous coronary intervention on patients Effects of myocardial injury markers, platelet function and inflammatory factors after intervention (PCI). Method A total of 150 patients with ACS admitted to the hospital from January 2021 to December 2022 were divided into groups according to different treatment methods. The control group (n = 75) was given nicodil combined with antiplatelet therapy, and the study group (n = 75) was given indobufen combined with nicodil combined with antiplatelet therapy. Both groups were treated for 2 weeks. The clinical efficacy of the two groups was compared, the changes of myocardial injury markers, platelet function and inflammatory factors before and after treatment were monitored, and the total incidence of adverse reactions was recorded. Results The total effective rate of the group treated with nicodil combined with indobufen was 98.67% higher than that of the control group treated with nicodil alone, 90.67% (χ2 = 4.754, P < 0.05). The levels of myocardial injury markers such as cTnI and CK-MB in the study group after treatment were lower than those in the control group (t = 15.492, 3.250, P < 0.05). The levels of platelet function indexes such as CD62p, CD63, GP'b/IIIa in the study group after treatment were lower than those in the control group (t = 2.034, 3.257, 2.221, P < 0.05). The levels of CRP, TNF- α, IL-6 and other inflammatory factors in the study group were lower than those in the control group after treatment (t = 21.862, 3.378, 2.131, P < 0.05). The total incidence of adverse reactions after treatment was 4.00% in the study group and 2.67% in the control group (P > 0.05). Conclusion The efficacy of indobufien combined with nicodil in the treatment of ACS is better than that of nicodil alone, and it can improve myocardial injury and platelet function after PCI, inhibit the release of inflammatory factors, and the incidence of adverse reactions is lower. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is one of the most common cardiovascular diseases and one of the leading causes of death in the world. Diet is the first step in the prevention of CHD. Vegetarians have significantly lower risk of death from CHD, but also have changes in the hemostasis system due to a deficiency of blood clotting factors. Cardiosurgical intervention for patients with hemostatic disorders should be performed in specialized centers with the necessary support. Case description. A 73-year-old patient G. was hospitalized to the National Amosov Institute of Cardiovascular Surgery with angina pectoris, weakness and edema. From the past medical history it is known that the patient has been following a diet with complete exclusion of meat and dairy products for 20 years, rarely eats fish; in addition, he smoked for 20 years at a young age. After coronary angiography, the patient developed bleeding from the oral cavity of unknown origin, which resolved on its own. According to the examination, the patient was found to have a multivessel lesion of the coronary arteries, and cardiosurgical intervention was indicated: coronary bypass surgery. At a case conference with cardiovascular surgeons, anesthesiologist and cardiologist, a decision was made to perform salvage cardiac surgery. The predicted mortality risk was 7.0% by the EuroSCORE II. The early postoperative period was complicated by bleeding with subsequent revision of the pericardium to identify the source of bleeding. Coagulopathy of unknown origin was suspected. Replacement hemostatic therapy was started, which included massive blood transfusions. The pace and level of exudation significantly decreased, the operation was completed. After surgical interventions and hemotransfusions, thromboelastography was performed and plasma hypercoagulation was detected. The patient was discharged for continued cardiopulmonary rehabilitation, and outpatient treatment was prescribed. Conclusions. This case report describes successful treatment of multivessel coronary artery disease by bypass grafting in a vegetarian patient with a coagulation disorder. Studies of the effects of a vegetarian diet on the hemostatic system indicate that vegetarians may have lower concentrations of hemostatic factors and that thrombin time is also prolonged due to the nutritional guidance provided by this diet. In addition, timely detection of a deficiency of blood coagulation factors in the plasma of a patient with such history can facilitate the diagnosis of the hemostasis system.

Severe thermal injury significantly impacts upon hemostasis and is associated with classical changes to the circulating platelet count with a nadir followed by a rebound thrombocytosis at days ~3 and ~15 post-injury, respectively. To date, few studies have assessed platelet function following thermal injury as platelet tests often require large quantities of blood, are not representative of normal platelet pathophysiology, and are usually dependent on a normal platelet count. The purpose of this study was to measure platelet thrombus formation in vitro using a whole blood flow chip-based system following thermal injury and to study how platelet counts may impact upon the measurement. Adult (≥16 years) patients (N = 10) with ≥ 20% total burn surface area (TBSA) burn were recruited within 24 h of injury. Healthy controls (N = 25) were also recruited. Whole blood counts were measured using a hematology analyzer (Sysmex XN-1000). Platelet function was measured using the Total Thrombus-formation Analyzer System (T-TAS) within chips coated with tissue factor and collagen at shear rates of either 600 sec−1 (AR chips) or 1200 sec−1 (HD chips), the latter test being independent of platelet count. We confirmed the classical nadir in platelet counts following severe thermal injury at days 2, 3, 4 (p < 0.0001) and day 5 (p

[Display omitted] [ABSTRACT FROM AUTHOR]

Peripheral arterial disease (PAD) affects approximately 236 million people worldwide. Therefore, this study aimed to investigate the relationship between CYP2C19 genotype polymorphisms and clopidogrel resistance (CR) following revascularization in patients with PAD. In total, 345 patients who underwent PAD revascularization were monitored for five years and risk factors for ischemic events were identified. Platelet reactivity and CYP2C19 genotypes were measured, and patients were classified as normal, intermediate, or poor metabolizers based on their genotypes. The study endpoint was defined as an ischemic event, that encompassed major adverse cardiovascular or limb events, or all-cause death. In this study, ischemic events following PAD revascularization were associated with patient age, prior minor amputation, the Rutherford category before revascularization, indications for revascularization, index ankle-branchial index before revascularization, CYP2C19 phenotypes, and CR. Intermediate and poor metabolism, the Rutherford category before revascularization, and CR were independent risk factors for ischemic events in patients after PAD revascularization. Similarly, intermediate and poor metabolism, the Rutherford category before revascularization, and CR were independent risk factors for ischemic events in patients with PAD after revascularization within five years. Intermediate and poor metabolizers had a higher platelet reactivity and risk of CR than normal metabolizers. However, poor metabolizers had a higher platelet reactivity and risk of CR than intermediate metabolizers. Furthermore, the hazard ratio for ischemic events increased with platelet reactivity. This effect was more prevalent in intermediate and poor metabolizers than in normal metabolizers. Ischemic events in patients after PAD revascularization were affected by independent risk factors. Decreased clopidogrel metabolism increased the platelet reactivity and CR in patients after PAD revascularization. Furthermore, high platelet reactivity was associated with an increased risk of ischemic events in patients with intermediate and poor metabolism. [Display omitted] • CYP2C19 phenotype and CR effects after revascularization for PAD remain unclear. • We evaluated these effects on ischemic events after revascularization over 5 years. • CYP2C19 phenotype and CR were independent risk factors for ischemic events. • Patients with impaired clopidogrel metabolism had a higher risk of CR. [ABSTRACT FROM AUTHOR]

Objectives: Flow cytometry with adenosine diphosphate (ADP) allows to characterize molecular changes of platelet function caused by this physiologically important activation, but the methodology has not been thoroughly investigated, standardized and characterized yet. We analyzed the influence of several major variables and chose optimal conditions for platelet function assessment. Methods: For activation, 2.5 μM CaCl2, 5 μM ADP and antibodies were added to diluted blood and incubated for 15 min. We analyzed kinetics of antibody binding and effects of their addition sequence, agonist concentration, blood dilution, exogenous calcium addition and platelet fixation. Results: We tested our protocol on 11 healthy children, 22 healthy adult volunteers, 9 patients after a month on dual antiplatelet therapy after percutaneous coronary intervention (PCI), 7 adult patients and 14 children with immune thrombocytopenia (ITP). We found that our protocol is highly sensitive to ADP stimulation with low percentage of aggregates formation. The assay is also sensitive to platelet function inhibition in post‐PCI patients. Finally, platelet preactivation with ITP plasma was stronger and caused increase in activation response to ADP stimulation compared to preactivation with low dose of ADP. Conclusions: Our assay is sensitive to antiplatelet therapy and platelet preactivation in ITP patients under physiological conditions with minimal percentage of aggregates formation. [ABSTRACT FROM AUTHOR]

This manuscript represents a republication of a manuscript originally published in STH in 1995. This republication is to help celebrate 50 years of publishing for STH. The original abstract follows. A new in vitro system for the detection of platelet dysfunction, PFA-100®, has been developed. It provides a quantitative measure of platelet function in anticoagulated whole blood. The system comprises a microprocessor-controlled instrument and a disposable test cartridge containing a biologically active membrane. The instrument aspirates a blood sample under constant vacuum from the sample reservoir through a capillary and a microscopic aperture cut into the membrane. The membrane is coated with collagen and epinephrine or adenosine 5′-diphosphate. The presence of these biochemical stimuli, and the high shear rates generated under the standardized flow conditions, result in platelet attachment, activation, and aggregation, slowly building a stable platelet plug at the aperture. The time required to obtain full occlusion of the aperture is reported as the "closure time." We have found that impairment of von Willebrand factor, or inhibition of platelet receptors glycoprotein Ib or IIb/IIIa with monoclonal antibodies or peptides, resulted in abnormal closure times. An antifibrinogen antibody, in contrast, failed to show any effect. The test appears to be sensitive to platelet adherence and aggregation abnormalities. The PFA-100® system has potential applications in routine evaluation of platelet function in the clinical setting because of its accuracy, case of operation, and rapid turnaround of results. [ABSTRACT FROM AUTHOR]

IntroductionElevated ambient pollution exposure is potentially linked to thromboembolism. However, the mechanisms by which particulate matter (PM) interferes with the balance of hemostatic system remain unclear. This study investigates PM-mediated hemostatic changes in individuals across unique seasonal variations of ambient pollution.MethodsThis prospective study was conducted between February and July 2020 during alterations in ambient pollution in Chiang Mai, Thailand. Blood tests from 30 healthy subjects were assessed at four-week intervals, four times in total. Various coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor (vWF), platelet count, and platelet functions, were evaluated. A mixed-effects model was used to analyze the impact of high PM2.5 and PM10 on hemostatic parameters.ResultsThirty male subjects with mean age of 38.9 ± 8.2 years, were included. High levels of PM2.5 and PM10 were significantly associated with PT shortening, with no such effect observed in aPTT. PM2.5 and PM10 values also positively correlated with vWF function, while vWF antigen levels remained unchanged. Soluble P-selectin showed a strong positive association with PM2.5 and PM10 levels. Platelet function analysis revealed no correlation with PM values.ConclusionShort-term exposure to elevated PM2.5 and PM10 concentrations was linked to shortened PT and enhanced vWF function in healthy individuals. Exploring the impact of these changes on clinically relevant thrombosis is crucial. Additional studies on the pathogenesis of pollution-related thrombosis are warranted for maintaining good health.

Objective: Associations between single nucleotide polymorphisms (SNPs) and aspirin resistance (AR) have been studied with variable results. The associations of genetic variants with AR may be helpful to explain why some individuals demonstrate aspirin insensitivity with this anti-platelet therapy. The purpose of this research was to investigate the effect of different genotypes in candidate genes on aspirin response in patients taking long-term aspirin therapy by measuring the serum thromboxane B2 (TXB2) and platelet function using the Multiplate® analyser. Methods: A total of 266 patients with stable coronary heart disease (CHD) taking low-dose aspirin for long periods of time and without any other anti-platelet drugs medications were enrolled into the study. They were required to take 80 mg of aspirin every morning for a week including the day before blood tests. Blood samples were collected 24 h after the last dose. The 80 mg dose of aspirin was taken orally and blood samples were collected again 1 h later. The serum TXB2 levels were measured in samples at 24 h post-dose and 1 h post-dose using the EIA kit and platelet activity was determined using the Multiplate® Impedance Platelet Aggregometry (ASPI) assay. Genotyping assays were performed by the TaqMan SNP genotyping technique. Results: Of the 266 patients, only 251 patients were enrolled in the present study. The PTGS1/COX1-1676 A > G (rs1330344) and the PTGS2/COX2-765 G > C (rs20417) SNPs showed significant associations with the ASPI measurements in samples taken at 24 h post-dose, but not with the values at 1 h post-dose or with the TXB2 levels (P

An editorial is presented which expresses the views on the ongoing debate regarding the clinical equivalence of apheresis and pooled platelet concentrates (PCs). Topics include the challenges in platelet transfusions for cancer patients, the comparative effectiveness of apheresis versus pooled PCs, and the implications of pathogen inactivation and leukoreduction on transfusion outcomes.

The assessment of platelet dysfunction is usually used by hematologists to diagnose inherited (such as Bernard-Soulier syndrome, platelet-type-von Willebrand disease, Glanzmann thrombasthenia, etc.), and acquired (symptomatic) platelet disorders (in hemoblastoses, uremia, liver cirrhosis, etc.), as well as to predict the risk of intraoperative bleeding in these groups of patients. Later, laboratory platelet function tests began to be used by cardiologists, first in experimental and clinical studies. In further years, attempts were made to introduce them into clinical practice. Current data show association between platelet hyperreactivity and pathogenesis of cardiovascular events. At the same time, despite the various consensus papers on assessing thrombotic and bleeding risk, monitoring antiplatelet therapy, including those published by Russian experts, in practice there are many subtleties and questions about the practical aspects of using laboratory tests. In addition, the definition of platelet phenotype does not have a clear concept. The review purpose was to describe laboratory methods for assessing the platelet function, to give more information to cardiologists about its practical value and to understand what basic scientists and physicians mean by the term “platelet phenotype”.

Increased platelet activity is a risk factor of thrombotic events in cardiovascular patients. We studied the relationship between platelet function, platelet size, and the content of reticulated platelets (RP) in patients with coronary heart disease (CHD, n = 55) and acute coronary syndrome (ACS, n = 95) receiving acetylsalicylic acid + clopidogrel or ticagrelor, respectively. The control group consisted of patients with risk factors for CHD, but with no CHD/ACS and free of antiplatelet drugs (n = 66). Platelet function was evaluated by the exposure of activated glycoprotein (GP) IIb-IIIa and P-selectin. In the control group, platelets were activated by TRAP (Thrombin Receptor Activating Peptide) 10 µM, and ADP 20, 5, 2.5 µM, and in the CHD/ACS groups, by TRAP 10 µM, and ADP 20 5 µM (±epinephrine 20 µM). Platelet size was assessed by the mean volume, % large forms, and forward scattering. RP were stained by thiazole orange. In the control group, activated GP IIb-IIIa and P-selectin correlated with platelet size and RP content after platelet activation by all agonists. Despite the decrease in platelet activity by antiplatelet drugs, most correlations (primarily for activated GP IIb-IIIa) were preserved in the CHD/ACS patients. In conclusion, increased platelet size and RP content are associated with increased platelet activity and the reduced efficacy of antiplatelet therapy.

Platelet activation and the complement system are mutually dependent. Here, we investigated the effects of storage time on complement activation and platelet function in routinely produced platelet concentrates. The platelet concentrates (n = 10) were stored at 22 °C for seven days and assessed daily for complement and platelet activation markers. Additionally, platelet function was analyzed in terms of their responsiveness to protease-activated receptor-1 (PAR-1) and thromboxane A2 receptor (TXA2R) activation and their capacity to adhere to collagen. Complement activation increased over the storage period for all analyzed markers, including the C1rs/C1-INH complex (fold change (FC) = 1.9; p < 0.001), MASP-1/C1-INH complex (FC = 2.0; p < 0.001), C4c (FC = 1.8, p < 0.001), C3bc (FC = 4.0; p < 0.01), and soluble C5b-9 (FC = 1.7, p < 0.001). Furthermore, the levels of soluble platelet activation markers increased in the concentrates over the seven-day period, including neutrophil-activating peptide-2 (FC = 2.5; p < 0.0001), transforming growth factor beta 1 (FC = 1.9; p < 0.001) and platelet factor 4 (FC = 2.1; p < 0.0001). The ability of platelets to respond to activation, as measured by surface expression of CD62P and CD63, decreased by 19% and 24% (p < 0.05) for PAR-1 and 69–72% (p < 0.05) for TXA2R activation, respectively, on Day 7 compared to Day 1. The extent of platelet binding to collagen was not significantly impaired during storage. In conclusion, we demonstrated that complement activation increased during the storage of platelets, and this correlated with increased platelet activation and a reduced ability of the platelets to respond to, primarily, TXA2R activation. [ABSTRACT FROM AUTHOR]

Background: The utility of neutrophil‐to‐lymphocyte ratio (NLR), platelet to‐lymphocyte ratio (PLR) and monocyte‐to‐lymphocyte ratio (MLR) as prognostic indicators has not been investigated in canine parvovirosis (CPV). Hypothesis: To evaluate whether these hematological ratios obtained at hospital admission in CPV are associated with outcome or duration of hospitalization. Animals.: Four hundred one client‐owned dogs presented with CPV. Methods‐Retrospective multicenter cohort study. Medical records were reviewed to identify dogs with CPV. Data regarding signalment, complete blood count at admission, duration of hospitalization and outcome were collected. Results: Of the 401 dogs included in the study, 336 (83.8%) survived to discharge. The median (25th and 75th percentiles) PLR in nonsurvivors (336.56 [159.84‐635.77]) was significantly higher than in survivors (217.65 [117.67‐389.65]) (P =.003). The area under the receiver‐operating characteristic curve for nonsurvival was 0.615 (95% CI [0.593‐0.691], P =.003). A cut off of 700 showed a 21.5% sensitivity and 90% specificity for nonsurvival. No association was observed between hospitalization duration and either hematological ratios or total WBC counts. The median (25th and 75th percentiles) lymphocyte count was below reference interval in all dogs and was significantly lower in the dogs which died (0.82 × 109/L [0.5‐1.87]) than in survivors (1.27 × 109/L [0.73‐2.22]) (P =.005). The median (25th and 75th percentiles) monocyte count however was lower in survivors (0.38 × 109/L [0.29‐1.59]), than in nonsurvivors (0.73 × 109/L [0.1‐2]) (P =.002). Conclusions: Evaluation of PLR at hospital admission might be a useful marker of disease severity and could have prognostic value in dogs with CPV. [ABSTRACT FROM AUTHOR]

Simple Summary: Platelets express the C-type lectin-like receptor 2 (CLEC-2) that enables binding to podoplanin (PDPN)-expressing tumor cells and, thereby, promote metastatic spread. An increased level of soluble CLEC-2 was reported in patients with thromboinflammatory and malignant disease, presumably released from activated platelets. In our study, we show that in vitro platelet activation leads to a significant decrease in CLEC-2 on platelets and in the plasma. We also found decreased levels of soluble CLEC-2 in plasma samples of patients with colorectal carcinoma (stages I to IV), breast cancer or melanoma (stages I to III) compared to healthy donors. Interestingly, in patients with glioblastoma, the plasma level of soluble CLEC-2 was significantly higher. We concluded that an increased plasma level of soluble CLEC-2 is not a suitable biomarker of platelet activation and tumor progression in most types of cancer. The C-type lectin-like receptor 2 (CLEC-2) is expressed on platelets and mediates binding to podoplanin (PDPN) on various cell types. The binding to circulating tumor cells (CTCs) leads to platelet activation and promotes metastatic spread. An increased level of soluble CLEC-2 (sCLEC-2), presumably released from activated platelets, was shown in patients with thromboinflammatory and malignant disease. However, the functional role of sCLEC-2 and the mechanism of sCLEC-2 release are not known. In this study, we focused on the effect of platelet activation on CLEC-2 expression and the sCLEC-2 plasma level in patients with cancer. First, citrated blood from healthy volunteer donors (n = 20) was used to measure the effect of platelet stimulation by classical agonists and PDPN on aggregation, CLEC-2 expression on platelets with flow cytometry, sCLEC-2 release to the plasma with ELISA and total CLEC-2 expression with Western blot analysis. Second, sCLEC-2 was determined in plasma samples from healthy donors (285) and patients with colorectal carcinoma (CRC; 194), melanoma (160), breast cancer (BC; 99) or glioblastoma (49). PDPN caused a significant increase in the aggregation response induced by classical agonists. ADP or PDPN stimulation of platelets caused a significant decrease in CLEC-2 on platelets and sCLEC-2 in the plasma, whereas total CLEC-2 in platelet lysates remained the same. Thus, the increased plasma level of sCLEC-2 is not a suitable biomarker of platelet activation. In patients with CRC (median 0.9 ng/mL), melanoma (0.9 ng/mL) or BC (0.7 ng/mL), we found significantly lower sCLEC-2 levels (p < 0.0001), whereas patients with glioblastoma displayed higher levels (2.6 ng/mL; p = 0.0233) compared to healthy controls (2.1 ng/mL). The low sCLEC-2 plasma level observed in most of the tumor entities of our study presumably results from the internalization of sCLEC-2 by activated platelets or binding of sCLEC-2 to CTCs. [ABSTRACT FROM AUTHOR]

Background: The Platelet function analyzer‐200 (PFA‐200) can determine the effect of clopidogrel in cats, but analysis traditionally must be performed at point‐of‐care (POC). The ability to ship samples of blood to a laboratory would allow widespread access. Objectives: We aimed to validate the shipping of blood samples for PFA‐200 analysis in cats to determine the effect of clopidogrel. Methods: Twenty healthy cats and 10 cats receiving clopidogrel were recruited. Blood was collected from cats and aliquoted into two samples, one was analyzed at POC within 2 hours using the PFA‐200, and the other was packaged and transported to a location 4 km away, stored, and transported back to the lab for analysis the following day. Results: Median closure times (CTs) with the collagen/adenosine diphosphate (COL/ADP) cartridge in healthy cats were 51.5 seconds (POC) and 78.8 seconds (shipped), which were significantly different (P < 0.001), and for cats on clopidogrel, median CTs were 147.5 seconds (POC) and 190 seconds (shipped), which were not significantly different (P = 0.131). Median CTs with the P2Y cartridge in healthy cats were 50.5 seconds (POC) and 64.9 seconds (shipped), which were significantly different (P = 0.03), and in cats receiving clopidogrel, median CTs were 300 seconds (POC) and 300 seconds (shipped) which were not significantly different (P = 1.000). Reference intervals for CTs differed for COL/ADP at POC (19.8–89.7 seconds) and shipped (50.9–161.6 seconds) and for P2Y at POC (35.5–118.8 seconds) and shipped (35.1–108.9 seconds). Receiver operating characteristics showed similar areas under the curve (AUCROCs) regarding the effect of clopidogrel for COL/ADP at POC (0.994 seconds) and shipped (0.932) and for P2Y at POC (0.904 seconds) and shipped (0.975 seconds). When classifying for the presence of clopidogrel effects, Cohen's Kappa was 0.62 for COL/ADP and 1.00 for P2Y. Conclusions: Shipping blood samples for PFA analysis are feasible with similar performance to POC analyses for determining the effect of clopidogrel in cats. [ABSTRACT FROM AUTHOR]

Abstract Background Patients with the rare disease; Hereditary haemorrhagic telangiectasia (HHT) often bleed from telangiectatic lesions in mucosal surfaces. Studies suggest that impaired platelet function may also play a role in their bleeding tendency. The aim of the present study was to investigate whether HHT-patients with epistaxis have impaired platelet function. Method We conducted a case–control study based on a sample size calculation and included 22 HHT-patients (inclusion criteria: epistaxis severity score ≥ 4, no intake of medicine affecting platelet function the last 5 days, HHT-type 1 or 2, age ≥ 18 years) and 20 controls. We assessed the platelet function with standard haemostasis parameters, flow cytometry (platelet function and micro aggregation), rotational thromboelastometry and Platelet Function Analyzer 200. Results We found no significant difference in mean platelet volume and immature platelet fraction and no difference in platelet activation as measured by exposure of CD62P, CD63P and PAC1 binding. Nor did we find a significant difference in platelet aggregation response in HHT-patients compared with the control group for all agonists (thrombin receptor activating peptide, adenosine diphosphate and collagen-related peptide). The PFA-200 analysis was without difference between the two groups and thromboelastometry showed no impairment of global haemostasis. Conclusion Reduced platelet function is unlikely to contribute to the frequent and long bleeding episodes that HHT-patients suffer from. We propose that further studies should focus on whether patients with HHT have hypercoagulability.

Background and Aim: Humans and dogs with azotemia can develop coagulation disorders. Therefore, this study aimed to evaluate the coagulation profiles and thromboelastographic parameters in dogs with acute kidney injury (AKI) and chronic kidney disease (CKD). Materials and Methods: In this prospective study, 31 client-owned dogs with renal azotemia (creatinine >220 µmol/L) were enrolled. Clinical signs of hemostatic disorders, complete blood count, coagulation profile, D-dimers, thromboelastography, and 28-day survival data were obtained and analyzed using the t-test, Mann–Whitney U test, and Chi-square test. Statistical significance was set at p < 0.05. Results: Seventeen dogs with AKI, 10 with CKD, and four with acute-on-chronic kidney injury (AoC) were enrolled. Ten dogs (AKI, 8/17; CKD, 2/10) had thrombocytopenia. Prothrombin time was prolonged in four dogs with AKI and longer in dogs with AKI than in dogs with CKD (p = 0.004). The activated partial thromboplastin time was prolonged in 23 dogs (AKI, 14/17; CKD, 7/10; AoC, 3/4) and was longer in azotemic dogs than in healthy control dogs (p = 0.003). Thromboelastographic tracings were hypocoagulable in three dogs with AKI and hypercoagulable in 16 dogs (AKI 4/17, CKD 9/10, AoC 3/4). The thromboelastographic values for maximum amplitude (p < 0.001) and global clot strength (p < 0.001) were lower in dogs with AKI than in those with CKD. Conclusion: Hypercoagulable thromboelastographic tracings were observed in dogs with CKD, whereas coagulation times were prolonged in dogs with AKI. However these findings should be validated by further studies.

Background: Patients with the rare disease; Hereditary haemorrhagic telangiectasia (HHT) often bleed from telangiectatic lesions in mucosal surfaces. Studies suggest that impaired platelet function may also play a role in their bleeding tendency. The aim of the present study was to investigate whether HHT-patients with epistaxis have impaired platelet function. Method: We conducted a case–control study based on a sample size calculation and included 22 HHT-patients (inclusion criteria: epistaxis severity score ≥ 4, no intake of medicine affecting platelet function the last 5 days, HHT-type 1 or 2, age ≥ 18 years) and 20 controls. We assessed the platelet function with standard haemostasis parameters, flow cytometry (platelet function and micro aggregation), rotational thromboelastometry and Platelet Function Analyzer 200. Results: We found no significant difference in mean platelet volume and immature platelet fraction and no difference in platelet activation as measured by exposure of CD62P, CD63P and PAC1 binding. Nor did we find a significant difference in platelet aggregation response in HHT-patients compared with the control group for all agonists (thrombin receptor activating peptide, adenosine diphosphate and collagen-related peptide). The PFA-200 analysis was without difference between the two groups and thromboelastometry showed no impairment of global haemostasis. Conclusion: Reduced platelet function is unlikely to contribute to the frequent and long bleeding episodes that HHT-patients suffer from. We propose that further studies should focus on whether patients with HHT have hypercoagulability. [ABSTRACT FROM AUTHOR]

Background: Minimally invasive extracorporeal circulation (MiECC) is employed as a strategy to attenuate the physiologic disturbance caused by cardiopulmonary bypass. The aim of this study was to compare the coagulation profile of MiECC to an optimized conventional extracorporeal circuit (OpECC) with regards to platelet function, rotational thromboelastometry and blood product usage. Methods: A retrospective analysis of coronary artery bypass grafting operations using either MiECC or OpECC was performed at a single institution. Results: A total of 112 patients were included, with 61 receiving MiECC and 51 OpECC patients. OpECC patients had a significantly larger BSA (1.95+/- 0.22m2 vs 1.88 +/- 0.18m2, p = 0.034), than those who received MiECC. No difference between groups was observed regarding red blood cell, plasma, and platelet transfusions. Functional platelet count during the warming phase of cardiopulmonary bypass was found to be higher in the MiECC group ((136 (102–171) x109/L vs 109 (94–136) x109/L), p = 0.027), as were functional platelets as a percent of total platelet count ((86 (77–91)% vs 76 (63–82)%), p = 0.003). There were no significant differences between other outcomes such as operative mortality, incidence of stroke, and intensive care unit length of stay. Conclusion: While we did not see a difference in blood transfusions, MiECC resulted in a statistically significant advantage over OpECC with regards to preservation of functional platelets. [ABSTRACT FROM AUTHOR]

The Platelet Function Analyzer 200 (PFA-200; Siemens) is an in vitro substitute for in vivo bleeding time that is designed to investigate platelet function in a more physiologic manner than traditional aggregometry. The analyzer reports a closure time (CT) as a marker of platelet function, and may also report the calculated platelet function measurement primary hemostasis components, PHC1 and PHC2. These incorporate the measured total volume (TV) of blood aspirated and the initial flow rate (IF). We determined, for the COL/ADP and P2Y cartridges, the median total volume (TVmedian), and RIs for CT, IF, TV, PHC1, and PHC2, and investigated the sensitivity and specificity of those parameters at the determined interpretation thresholds in determination of the clopidogrel effect. Healthy client-owned cats were recruited prospectively to determine RIs for CT, IF, TV, PHC1, and PHC2. Healthy blood-donor cats and cats on clopidogrel therapy were included retrospectively to determine test performance. In 20 healthy cats, RIs for COL/ADP were CT (19.5–87.2 s), IF (199–278 µL/min), TV (199–332 µL), PHC1 (94–106%), and PHC2 (52–148%); and for P2Y, CT (4.2–94.3 s), IF (112–208 µL/min), TV (151–294 µL), PHC1 (35–178%), and PHC2 (90–109%). CVs were calculated for all of these values. Specificity for detection of the clopidogrel effect was calculated from a group of healthy blood donors, and sensitivity for detection of the clopidogrel effect from a group of cats with known clopidogrel effect. Sensitivity and specificity were, for COL/ADP: CT (83.3%, 66.6%), IF (41.4%, 83.3%), TV (83.3%, 100%), PHC1 (100%, 100%) and PHC2 (100%, 83.3%); and for P2Y: CT (100%, 94.4%), IF (30%, 44.4%), TV (100%, 94.4%), PHC1 (100%, 100%), and PHC2 (100%, 97.7%). These PFA-200 values may be beneficial in the determination of platelet function in cats. [ABSTRACT FROM AUTHOR]

Snake venoms are rich in valuable substances that have medical potential in the diagnosis and treatment of hemostatic diseases. The present paper was aimed at the purification and functional characterization basis of a thrombin-like enzyme and its role in the functioning of the coagulation cascade and platelet aggregation pathway. A thrombin-like serine protease was purified from the Iranian Echis carinatus venom (TLIECV), employing a one-step chromatographic procedure. This peptide was collected in high yield and purity by a single chromatographic step using RP-HPLC equipped with a C18 column. This peptide showed a 3000 Da molecular weight in gelelectrophoresis. Evidence in the SDS-PAGE gel has confirmed high recovery of fraction in optimal terms. Subsequently, this peptide was identified via its intact molecular mass and peptide mass fingerprint (PMF) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Multiple sequence alignments were performed by ClustalW, the Bioedit software. Molegro Data Modeller (MDM) 3.0 software was used to predict the putative tertiary structure of the peptide. The enzyme possessed fibrinogenolytic, procoagulant, and aggregation inducer properties. Moreover, the SDS-PAGE (12%) was applied to examine fibrinogenolytic function. The purified enzyme degraded the Aα chain of fibrinogen while the Bβ and γ chains were not digested. According to that, the deficient human plasma in factor X and normal human plasma were also coagulated by TLIECV, it takes part in the common and intrinsic routes of the coagulation cascade. These findings proved that TLIECV is a serine protease identical to procoagulant thrombin-like snake venom proteases; however, it specifically releases the Aα chain of bovine fibrinogen. Because of its function to make up for the deficiency of factor X and its platelet aggregation inducer property, TLIECV could be considered a molecular impact to reveal the hemostasis mechanisms. [ABSTRACT FROM AUTHOR]

Background: Examination of the platelet aggregation test (PAT) and Maximum Amplitude -- Thromboelastography (MA-TEG) are two ways of assessing platelet function. Examination of the platelet aggregation test aims to detect any disturbance of platelet function based on changes in light transmission after adding an agonist. At the same time, the MA parameter of TEG shows the strength of the clot, which is related to platelet count and function, as well as their interaction with fibrin. This study aims to analyze the relationship between the results of the platelet aggregation test and the MA parameter of TEG in assessing platelet function in COVID-19 patients. Method: The type of research used is correlation research with a sampling technique, purposive sampling. Examination of PAT used the Aggregometer Chrono-Log Model 490 while checking MA values used a Thromboelastography 5000. The correlations for the variables studied were analyzed statistically. Results: The results of PAT in COVID-19 patients for each agonist showed different results. Most of the epinephrine and ADP agonists (60%) showed normoaggregation. In comparison, most collagen agonists (66.6%) showed hypoaggregation, while the value of the parameter MA-TEG in COVID-19 patients showed increased results: 75.2 (34.8 - 82.2). The correlation between each PAT agonist and MA-TEG showed no correlation. This conclusion is drawn based on the p-value > 0.05. Each p-value between variables is epinephrine with MA-TEG = 0.689, ADP with MA-TEG = 0.945 and collagen with MA-TEG) = 0.282.Conclusion: There is no significant correlation between PAT and TEG's MA parameter in assessing platelet function in COVID-19 patients. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the safety and efficacy of salvianolate injection in preventing deep vein thrombosis (DVT) following total hip replacement. Methods: A total of 114 patients who underwent total hip replacement at Department of Trauma, Fengfeng General Hospital of North China Medical and Health Group, Handan City, China from March 2019 to March 2022 were enrolled. Patients were randomly divided into study group (n = 57) and control group (n = 57). The control group received conventional treatment (low molecular weight heparin) while the study group was administered salvianolate injection combined with conventional treatment. Incidence of deep vein thrombosis (DVT) at 7 and 14 days after surgery, platelet function indices, including platelet count, glycoprotein IIb/IIIa (GP IIb/IIIa), and CD62P, coagulation function indices (prothrombin time (PT), fibrinogen (FIB) and D-dimer), and hemodynamics indices, viz, peak blood flow velocity (Vp) and average velocity (Va) were investigated and compared. Results: Incidence of DVT was 1.75 % (1/57) at 7 days and 5.26 % (3/57) at 14 days in the study group, and 5.26 % (3/57) at 7 days and 17.54 % (10/57) at 14 days in control group. Incidence of DVT in the study group was significantly reduced compared to control group 14 days after surgery (p < 0.05). Also, the study group had significantly lower visual analog scale (VAS) scores at 7 days and 1 month after surgery compared to control group (p < 0.05). Platelet count, GPIIb/IIIa, and CD62P in the study group were significantly lower than in control group (p < 0.05). Conclusion: Salvianolate injection significantly prevents DVT after total hip replacement, improves hemodynamics, and coagulation function, and thus contributes to recovery of hip function. Further clinical trials are, however, required to validate these findings. [ABSTRACT FROM AUTHOR]

Aging is a multifaceted process that unfolds at both the individual and cellular levels, resulting in changes in platelet count and platelet reactivity. These alterations are influenced by shifts in platelet production, as well as by various environmental factors that affect circulating platelets. Aging also triggers functional changes in platelets, including a reduction in RNA content and protein production capacity. Older individuals and RNA-rich immature platelets often exhibit hyperactivity, contributing significantly to pathologic conditions such as cardiovascular diseases, sepsis, and thrombosis. However, the impact of aging on surface receptor expression of circulating platelets, particularly whether these effects vary between immature and mature platelets, remains largely unexplored. Thus, we investigated the expression of certain surface and activation receptors on platelets from young and old mice as well as on immature and mature platelets from mouse models of regenerative thrombocytopenia by flow cytometry. Our findings indicate that aged mice show an upregulated expression of the platelet endothelial cell adhesion molecule-1 (CD31), tetraspanin-29 (CD9), and Toll-like receptor 2 (TLR2) compared to their younger counterparts. Interestingly, when comparing immature and mature platelets in both young and old mice, no differences were observed in mature platelets. However, immature platelets from young mice displayed higher surface expression compared to immature platelets from old mice. Additionally, in mouse models of regenerative thrombocytopenia, the majority of receptors were upregulated in immature platelets. These results suggest that distinct surface receptor expressions are increased on platelets from old mice and immature platelets, which may partially explain their heightened activity and contribute to an increased thrombotic risk. [ABSTRACT FROM AUTHOR]

Purpose: Obese patients exhibit an overall increased platelet reactivity and a reduced sensitivity to antiplatelet therapy. The aim of this study is to evaluate the platelet reactivity measured by impedance aggregometry in overweight and obese patients and chronic coronary syndrome (CCS) that were treated with dual antiplatelet therapy (DAPT). Methods: Platelet aggregation was assessed by impedance aggregometry in patients with CCS receiving DAPT (aspirin plus clopidogrel). We compared the platelet reactivity in patients with a normal weight versus overweight or obese patients. Furthermore, the correlation between the body mass index (BMI) and adenosine diphosphate- (ADP-) or thrombin receptor-activating peptide- (TRAP-) dependent platelet aggregation was analyzed. Results: 64 patients were included in the study of which 35.9% were patients with normal weight. A higher ADP- and TRAP-dependent platelet reactivity was observed in overweight and obese patients (ADP: median 27 units (U) [IQR 13–39.5] vs. 7 U [6–15], p < 0.001 and TRAP: 97 U [73–118.5] vs. 85 U [36–103], p = 0.035). Significant positive correlations were observed between agonist-induced platelet reactivity and BMI. Conclusion: Despite the use of DAPT, a higher platelet reactivity was found in overweight and obese patients with CCS. If these patients will benefit from treatment with more potent platelet inhibitors, it needs to be evaluated in future clinical trials. [ABSTRACT FROM AUTHOR]

Objective: Changes of platelet distribution width (PDW) have been observed in women with unexplained recurrent pregnancy loss (URPL). However, relevant previous studies showed inconsistent results. We performed a meta-analysis to comprehensively evaluate the association between PDW and URPL. Methods: Observational studies reporting the difference of PDW between women with and without URPL were retrieved by searching PubMed, Embase, Web of Science, Wanfang, and CNKI. A random-effect model was used to pool the results by incorporating potential heterogeneity. Results: Eleven case-control studies with 1847 women with URPL and 2475 healthy women were included. Age was matched for all studies between cases and controls. Pooled results showed women with URPL had significantly increased level of PDW (mean difference [MD]: 1.54%, 95% CI: 1.04 to 2.03, p < 0.05; I2 =77%). Subgroup analysis showed consistent result for URPL defined as ≥ 2 (MD: 1.45%, p = 0.003) and ≥ 3 (MD: 1.61%, p < 0.001) failed clinical pregnancies, and in studies compared to women with normal pregnancy (MD: 2.02%, p < 0.001) and non-pregnant healthy women (MD: 1.34%, p < 0.001). Results of the meta-analysis also showed that increment of PDW was associated with higher odds of URPL (per 1 unit, odds ratio: 1.26, 95% CI: 1.17 to 1.35, p < 0.001; I2 = 0%). Conclusions: Women with URPL had significantly increased levels of PDW compared to healthy women without URPL, which suggest that higher PDW may predict the risk of URPL. [ABSTRACT FROM AUTHOR]

Background and Objectives: Cold‐stored whole blood (CSWB) is increasingly used in damage control resuscitation. Haemostatic function of CSWB seems superior to that of reconstituted whole blood, and it is sufficiently preserved for 14–21 days. To provide evidence for a yet insufficiently studied aspect of prehospital CSWB use, we compared in vitro haemostatic properties of CSWB and currently used in‐hospital and prehospital blood component therapies. Materials and Methods: Blood was obtained from 24 O RhD positive male donors. Three products were prepared: CSWB, in‐hospital component therapy (red blood cells [RBCs], OctaplasLG and platelets 1:1:1) and prehospital component therapy (RBCs and lyophilized plasma 1:1). Samples were drawn on days 1 and 14 of CSWB or RBC cold storage. On day 14, platelet concentrates at their expiry (5 days) were used for 1:1:1 mixing. Conventional clotting assays, rotational thromboelastometry, thrombin formation and platelet function were assessed. Results: Haemoglobin, platelet count, fibrinogen and coagulation factor levels remained closest to physiological in CSWB. Factor VIII activity decreased markedly by day 14 in CSWB. The decline in platelet function was prominent in CSWB. However, CSWB on day 14 yielded physiological EXTEM MCF, suggesting haemostatically sufficient platelet function. Despite haemodilution and lower coagulation factor levels, in‐hospital component therapy was haemostatically adequate. Prehospital component therapy formed the weakest clots. Thrombin formation potential remained comparable and stable in all groups. Conclusion: Current prehospital component therapy fails to offer the clotting potential that CSWB does. CSWB and current in‐hospital 1:1:1 component therapy show similar haemostatic potential until 14 days of storage. [ABSTRACT FROM AUTHOR]

Pathogen reduction technologies (PRTs) such as Mirasol and Intercept were developed to eliminate transfusion-transmitted infections. The impact of PRTs on platelet function during the storage period, their effect on platelet storage lesions, and the optimal storage duration following PRTs have not been clearly defined. The aim of this study was to systematically review the existing literature and investigate the impact of PRTs on functional alterations of PRT-treated platelets during the storage period. The authors identified 68 studies suitable to be included in this review. Despite the high heterogeneity in the literature, the results of the published studies indicate that PRTs may increase platelet metabolic activity, accelerate cell apoptosis, and enhance platelet activation, which can subsequently lead to a late exhaustion of activation potential and reduced aggregation response. However, these effects have a minor impact on platelet function during the early storage period and become more prominent beyond the fifth day of the storage period. Large in vivo trials are required to evaluate the effectiveness of PRT-treated platelets during the storage period and investigate whether their storage can be safely extended to more than 5 days, and up to the traditional 7-day storage period. [ABSTRACT FROM AUTHOR]

Previous studies have described impaired platelet function after cardiopulmonary bypass (CPB). Whether this is still valid in contemporary cardiac surgery is unclear. This study aimed to quantify changes in function and number of platelets during CPB in a present-day cardiac surgery cohort. Prospective, controlled clinical study. A single-center university hospital. Thirty-nine patients scheduled for coronary artery bypass graft surgery with CPB. Platelet function and numbers were measured at 6 timepoints in 39 patients during and after coronary artery bypass graft surgery; at baseline before anesthesia, at the end of CPB, after protamine administration, at intensive care unit (ICU) arrival, 3 hours after ICU arrival, and on the morning after surgery. Platelet function was assessed with impedance aggregometry and flow cytometry. Platelet numbers are expressed as actual concentration and as numbers corrected for dilution using hemoglobin as a reference marker. There was no consistent impairment of platelet function during CPB with either impedance aggregometry or flow cytometry. After protamine administration, a decrease in platelet function was seen with impedance aggregometry and for some markers of activation with flow cytometry. Platelet function was restored 3 hours after arrival in the ICU. During CPB (85.0 ± 21 min), the number of circulating platelets corrected for dilution increased from 1.73 ± 0.42 × 109/g to 1.91 ± 0.51 × 109/g (p < 0.001). During cardiac surgery with moderate CPB times, platelet function was not impaired, and no consumption of circulating platelets could be detected. Administration of protamine transiently affected platelet function. [ABSTRACT FROM AUTHOR]

Background and Aim: Humans and dogs with azotemia can develop coagulation disorders. Therefore, this study aimed to evaluate the coagulation profiles and thromboelastographic parameters in dogs with acute kidney injury (AKI) and chronic kidney disease (CKD). Materials and Methods: In this prospective study, 31 client-owned dogs with renal azotemia (creatinine >220 µmol/L) were enrolled. Clinical signs of hemostatic disorders, complete blood count, coagulation profile, D-dimers, thromboelastography, and 28-day survival data were obtained and analyzed using the t-test, Mann-Whitney U test, and Chi-square test. Statistical significance was set at p < 0.05. Results: Seventeen dogs with AKI, 10 with CKD, and four with acute-on-chronic kidney injury (AoC) were enrolled. Ten dogs (AKI, 8/17; CKD, 2/10) had thrombocytopenia. Prothrombin time was prolonged in four dogs with AKI and longer in dogs with AKI than in dogs with CKD (p = 0.004). The activated partial thromboplastin time was prolonged in 23 dogs (AKI, 14/17; CKD, 7/10; AoC, 3/4) and was longer in azotemic dogs than in healthy control dogs (p = 0.003). Thromboelastographic tracings were hypocoagulable in three dogs with AKI and hypercoagulable in 16 dogs (AKI 4/17, CKD 9/10, AoC 3/4). The thromboelastographic values for maximum amplitude (p < 0.001) and global clot strength (p < 0.001) were lower in dogs with AKI than in those with CKD. Conclusion: Hypercoagulable thromboelastographic tracings were observed in dogs with CKD, whereas coagulation times were prolonged in dogs with AKI. However these findings should be validated by further studies. [ABSTRACT FROM AUTHOR]

Summary: Hypofibrinolysis is a recently-recognized risk factor for recurrent cardiovascular events in patients with ST-segment elevation myocardial infarction (STEMI), but the mechanistic determinants of this are not well understood. In patients with STEMI, we show that the effectiveness of endogenous fibrinolysis in whole blood is determined in part by fibrinogen level, high sensitivity C-reactive protein, and shear-induced platelet reactivity, the latter directly related to the speed of thrombin generation. Our findings strengthen the evidence for the role of cellular components and bidirectional crosstalk between coagulatory and inflammatory pathways as determinants of hypofibrinolysis.