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Platelets are among the most abundant cells within the circulation. Given that the platelet lifespan is 7 to 10 days in humans, a constant production of around 100 billion platelets per day is required. Platelet production from precursor cells called megakaryocytes is one of the most enigmatic processes in human biology. Although it has been studied for over a century, there is still controversy about the exact mechanisms leading to platelet release into circulation. The formation of proplatelet extensions from megakaryocytes into bone marrow sinusoids is the best-described mechanism explaining the origin of blood platelets. However, using powerful imaging techniques, several emerging studies have recently raised challenging questions in the field, suggesting that small platelet-sized structures called buds might also contribute to the circulating platelet pool. How and whether these structures differ from microvesicles or membrane blebs, which have previously been described to be released from megakaryocytes, is still a matter of discussion. In this review, we will summarize what the past and present have revealed about platelet production and whether mature blood platelets might emerge via different mechanisms.
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Plaquetas , Megacariócitos , Trombopoese , Humanos , Plaquetas/metabolismo , Megacariócitos/citologia , Megacariócitos/metabolismo , Animais , Trombopoese/fisiologiaRESUMO
Melasma is a prevalent dermatological challenge with limited therapeutic interventions. Platelet-rich plasma (PRP) has been increasingly explored for its potential benefits in various dermatological conditions. This study aimed to systematically review the efficacy and safety of PRP in the treatment of melasma. A comprehensive search in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was executed in January 2024 using PubMed, focusing on studies investigating the efficacy and safety of PRP in melasma. Criteria for inclusion were clinical trials and controlled studies examining PRP's role in melasma treatment, while exclusions covered reviews, non-English articles, and studies older than 10 years, among others. Eight studies were included, with the majority targeting female participants. The research displayed consistent positive outcomes, whether PRP was used alone or synergistically with treatments like hydroquinone and tranexamic acid. However, positive studies with the combination of PRP and other drugs will not provide the actual safety and efficacy data of PRP. The combined treatment approaches often showed enhanced results. Satisfaction rates among patients and reductions in the melasma area and severity index (MASI) scores were common findings across the studies, emphasizing the potential of PRP in melasma management. In conclusion, PRP emerges as a promising therapeutic intervention for melasma. Whether as a standalone treatment or combined with established methods, PRP presents significant potential in melasma's clinical management, warranting further expansive trials to substantiate its long-term efficacy and safety.
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Patient characteristics and platelet responses at romiplostim initiation according to the duration of immune thrombocytopenia (ITP) are poorly understood. Amongst romiplostim-exposed adults with ITP lasting ≥6 months during 2009-2018 in Denmark, Sweden, and Norway, we examined characteristics at romiplostim initiation, romiplostim dosage, and durable platelet response (≥75% of measurements ≥50 × 109/L at 14-24 weeks) for subcohorts with newly diagnosed (duration <3 months), persistent (3-12 months), or chronic (>12 months) ITP initiating romiplostim. The 285 romiplostim initiators comprised 81 (28%) with newly diagnosed, 47 (16%) with persistent, and 157 (55%) with chronic ITP. More patients with newly diagnosed ITP than longer ITP duration, had low comorbidity levels, two or more prior ITP therapies, and previous bleeding requiring hospitalisation. The median romiplostim doses were similar across subcohorts. During treatment, median platelet counts were similar across subcohorts (75-76 × 109/L), and the durable platelet response was 64.6%, 52.9%, and 52.7% for newly diagnosed, persistent, and chronic ITP, respectively. After treatment cessation, the median platelet count was 138 × 109/L, 68 × 109/L, and 71 × 109/L, respectively. In conclusion, newly diagnosed patients, compared with romiplostim initiators with longer disease duration, had more severe ITP, higher frequency of durable platelet response, and higher median platelet count after cessation.
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Platelets are crucial for maintaining physiological equilibrium, thrombosis formation, inflammation, bacterial defense, wound repair, angiogenesis, and tumorigenesis. In the Pediatric Intensive Care Unit (PICU), children frequently exhibit platelet reductions or functional alterations due to diverse pathological conditions, which significantly influence disease progression and therapeutic approaches. We analyzed the association between platelets count and its derived parameters and all-cause mortality. Adjusted smoothing spline plots, subgroup analysis and segmented multivariate logistic regression analysis were conducted to estimate the relative risk between proportional risk between platelets and all-cause mortality. Of the 11625 children, 677 (5.82%) died. After adjusting for confounders, there was a negative association between platelets and the risk of all-cause mortality in PICU. For every 100 × 10^9/L increase in platelets, the risk of death was reduced by 17% (adjusted OR = 0.83, 95% CI: 0.78, 0.89). The results of sensitivity analysis showed that in different stratified analyses (age, ICU category,WBC Count), the effect of platelets count on all-cause mortality remained stable. After adjusting for inflammation, nutrition, and liver function factors, platelets reduction is still an independent risk factor for PICU all-cause mortality.
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Plaquetas , Unidades de Terapia Intensiva Pediátrica , Humanos , Unidades de Terapia Intensiva Pediátrica/estatística & dados numéricos , Masculino , Feminino , Criança , Pré-Escolar , Lactente , Contagem de Plaquetas , Adolescente , Fatores de RiscoRESUMO
During 2018-2021, eight septic transfusion reactions occurred from transfusion of platelet units contaminated with Acinetobacter spp., Staphylococcus saprophyticus, Leclercia adecarboxylata, or a combination of those environmental organisms. Whether biofilm formation contributed to evasion of bacterial risk mitigations, including bacterial culture, point-of-care testing, or pathogen-reduction technology, is unclear. We designed a 12-well plate-based method to evaluate environmental determinants of single-species and multispecies biofilm formation in platelets. We evaluated bacteria isolated from septic transfusion reactions for biofilm formation by using crystal violet staining and enumeration of adherent bacteria. Most combinations of bacteria had enhanced biofilm production compared with single bacteria. Combinations involving L. adecarboxylata had increased crystal violet biofilm production and adherent bacteria. This study demonstrates that transfusion-relevant bacteria can produce biofilms well together. More work is needed to clarify the effect of biofilms on platelet bacterial risk control strategies, but US Food and Drug Administration-recommended strategies remain acceptable.
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INTRODUCTION: The Ad26.COV2·S (Janssen/Johnson & Johnson) COVID-19 vaccine, has been rarely associated with vaccine-induced immune thrombocytopenia and thrombosis (VITT). We investigated the prevalence of anti-PF4 antibody positivity, thrombocytopenia, D-dimer elevation, plasmatic thromboinflammatory markers, and platelet functional assays following Ad26.COV2·S vaccination in Rio de Janeiro, Brazil. METHODS: From July to September 2021, participants were assessed prior, 1, and 3 weeks post-vaccination. Platelet count and D-dimer were measured at each visit and anti-PF4 at week 3. A positive anti-PF4 prompted retrospective testing of the sample from week 0. Individuals with new thrombocytopenia or elevated D-dimer, positive anti-PF4, and 38 matched controls without laboratory abnormalities were evaluated for plasmatic p-selectin, tissue factor, and functional platelet activation assays. RESULTS: 630 individuals were included; 306 (48.57%) females, median age 28 years. Forty-two (6.67%) presented ≥1 laboratory abnormality in week 1 or 3. Five (0.79%) had thrombocytopenia, 31 (4.91%) elevated D-dimer, and 9 (1.57%) had positive anti-PF4 at week 3. Individuals with laboratory abnormalities and controls showed a slight increase in plasmatic p-selectin and tissue factor. Ten individuals with laboratory abnormalities yielded increased surface expression of p-selectin, and their ability to activate platelets in a FcγRIIa dependent manner was further evaluated. Two were partially inhibited by high concentrations of heparin and blockage of FcγRII with IV.3 antibody. Plasma obtained before vaccination produced similar results, suggesting a lack of association with vaccination. CONCLUSIONS: Vaccination with Ad26.COV2·S vaccine led to a very low frequency of low-titer positive anti-PF4 antibodies, elevation of D-dimer, and mild thrombocytopenia, with no associated clinically relevant increase in thromboinflammatory markers and platelet activation.
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Stroke leaves a great economic burden due to its high morbidity and mortality. Rapid revascularization of targeted vessel(s) is the effective treatment for ischemic stroke, but subsequent ischemia-reperfusion (I/R) injury is a common complication following revascularization, leading to microcirculation dysfunction and infarct volume increase. Thrombo-inflammation, the interaction between thrombosis and inflammation, plays a critical role in the pathophysiology of ischemic stroke. In the context of I/R injury, thrombo-inflammation consists of platelet activation, endothelial injury, and inflammatory cell infiltration. Numerous studies are devoted to exploring methods of regulating thrombo-inflammation to mitigate I/R injury post-stroke, including blocking activations of platelets and neutrophils. Drugs such as antiplatelet medications, anticoagulants, and glucocorticoids have been confirmed to have the potential to regulate thrombo-inflammation. Furthermore, several recently developed drugs have also shown promises in relieving I/R injury by manipulating thrombo-inflammation. However, the majority of these studies are still in the preclinical stage. Herein, in this review, we will address the mechanisms of thrombo-inflammation in ischemic stroke, related research advances, and particularly the clinical feasibility of thrombo-inflammation as a therapeutic strategy against I/R injury.
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Despite the predisposition to bleeding, patients with immune thrombocytopenia (ITP) may also have an increased risk of arterial and venous thrombosis, which can contribute to significant morbidity. The risk of thrombosis increases with age and the presence of cardiovascular risk factors. This narrative review explores the multifactorial nature of thrombosis in ITP, focusing on new pathological mechanisms, emerging evidence on the association between established treatments and thrombotic risk, the role of novel treatment approaches, and the challenges in assessing the balance between bleeding and thrombosis in ITP. The review also explores the challenges in managing acute thrombotic events in ITP, since the platelet count does not always reliably predict either the risk of bleeding or thrombosis and antithrombotic strategies lack specific guidelines for ITP. Notably, second-line therapeutic options, such as splenectomy and thrombopoietin receptor agonists (TPO-RAs), exhibit an increased risk of thrombosis especially in older individuals or those with multiple thrombotic risk factors or previous thrombosis, emphasizing the importance of careful risk assessment before treatment selection. In this context, it is important to consider second-line therapies such as rituximab and other immunosuppressive agents, dapsone and fostamatinib, which are not associated with increased thrombotic risk. In particular, fostamatinib, an oral spleen tyrosine kinase inhibitor, has promisingly low thrombotic risk. During the current era of the emergence of several novel ITP therapies that do not pose additional risks for thrombosis, it is critical to outline evidence-based strategies for the prevention and treatment of thrombosis in ITP patients.
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BACKGROUND: The optimal duration for dual antiplatelet therapy (DAPT) after stent-assisted coiling (SAC) of intracranial aneurysms is unclear. Longer-term therapy may reduce thrombotic complications but increase the risk of bleeding complications. METHODS: A retrospective review of prospectively maintained data at 12 institutions was conducted on patients with unruptured intracranial aneurysms who underwent SAC between January 1, 2016 and December 31, 2020, and were followed ≥6 months postprocedure. The type and duration of DAPT, stent(s) used, outcome, length of follow-up, complication rates, and incidence of significant in-stent stenosis (ISS) were collected. RESULTS: Of 556 patients reviewed, 450 met all inclusion criteria. Nine patients treated with DAPT <29 days after SAC and 11 treated for 43-89 days were excluded from the final analysis as none completed their prescribed duration of treatment. Eighty patients received short-term DAPT. There were no significant differences in the rate of thrombotic complications during predefined periods of risk in the short, medium, or long-term treatment groups (1/80, 1.3%; 2/188, 1.1%; and 0/162, 0%, respectively). Similarly, no differences were found in the rate of hemorrhagic complications during period of risk in any group (0/80, 0%; 3/188, 1.6%; and 1/162, 0.6%, respectively). Longer duration DAPT did not reduce ISS risk in any group. CONCLUSIONS: Continuing DAPT >42 days after SAC did not reduce the risk of thrombotic complications or in-stent stenosis, although the risk of additional hemorrhagic complications remained low. It may be reasonable to discontinue DAPT after 42 days following non-flow diverting SAC of unruptured intracranial aneurysms.
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The correlation between obesity and cardiovascular disease has long been understood, yet scant investigations endeavored to determine the impact of an obesogenic diet on platelet activation or function. As platelets drive clot formation, the terminus of cardiovascular events, we aimed to elucidate the longitudinal effect of an obesogenic diet on platelet phenotype by assessing markers of platelet activation using flow cytometry. Male, weanling mice were fed either a Western diet (30% kcal sucrose, 40% kcal fat, 8.0% sodium) or Control diet (7% kcal sucrose, 10% kcal fat, 0.24% sodium). At 12, 16 and 20 weeks on diets, platelets were collected and stained to visualize glycoprotein Ibα (GPIbα), P-selectin and the conformationally active state of αIIbß3 (a platelet specific integrin) after collagen stimulation. At all time points, a Western diet reduced GPIbα and αIIbß3 expression in platelets broadly while P-selectin levels were unaffected. However, P-selectin was diminished by a Western diet in the GPIbα- subpopulation. Thus, a Western diet persistently primed platelets towards a blunted activation response as indicated by reduced active αIIbß3 and P-selectin surface expression. This study provides a first look at the influence of diet on platelet activation and revealed that platelet activation is susceptible to dietary intervention.
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Plaquetas , Dieta Ocidental , Selectina-P , Ativação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Animais , Masculino , Dieta Ocidental/efeitos adversos , Camundongos , Plaquetas/metabolismo , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Selectina-P/metabolismo , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Obesidade/sangue , Obesidade/etiologiaRESUMO
Extracellular vesicles (EVs) are relatively recently discovered biological nanoparticles that mediate intercellular communication. The development of new methods for the isolation and characterization of EVs is crucial to support further studies on these small and structurally heterogenous vesicles. New scalable production methods are also needed to meet the needs of future therapeutic applications. A reliable inline detection method for the EV manufacturing process is needed to ensure reproducibility and to identify any possible variations in real time. Here, we demonstrate the use of an inline Raman detector in conjunction with anion exchange chromatography for the isolation of EVs from human platelets. Anion-exchange chromatography can be easily coupled with multiple inline detectors and provides an alternative to size-based methods for separating EVs from similar-sized impurities, such as lipoprotein particles. Raman spectroscopy enabled us to identify functional groups in EV samples and trace EVs and impurities in different stages of the process. Our results show a notable separation of impurities from the EVs during anion-exchange chromatography and demonstrate the power of inline Raman spectroscopy. Compared to conventional EV analysis methods, the inline Raman approach does not require hands-on work and can provide detailed, real-time information about the sample and the purification process.
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Plaquetas , Vesículas Extracelulares , Análise Espectral Raman , Análise Espectral Raman/métodos , Cromatografia por Troca Iônica/métodos , Humanos , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo , Plaquetas/metabolismo , Plaquetas/química , ÂnionsRESUMO
BACKGROUND: Diabetes carries an increased risk of cardiovascular disease and thromboembolic events. Upon endothelial dysfunction, platelets bind to endothelial cells to precipitate thrombus formation, however, it is unclear which surface proteins regulate platelet-endothelium interaction. We and others have shown that peri/epicellular (pec) protein disulphide isomerase A1 (pecPDI) influences the adhesion and migration of vascular cells. OBJECTIVES: We investigated whether pecPDI regulates adhesion-related molecules on the surface of endothelial cells and platelets that influence the binding of these cells in hyperglycaemia. METHODS: Immunofluorescence was used to assess platelet-endothelium interaction in vitro, cytoskeleton reorganization and focal adhesions. Hydrogen peroxide production was assessed via Amplex Red assays. Cell biophysics was assessed using atomic force microscopy. Secreted proteins of interest were identified through proteomics (secretomics) and targets were knocked down using siRNA. PDI contribution was assessed using whole-cell PDI or pecPDI inhibitors or siRNA. RESULTS: Platelets of healthy donors adhered more onto hyperglycaemic HUVECs. Endothelial, but not platelet, pecPDI regulated this effect. Hyperglycaemic HUVECs showed marked cytoskeleton reorganization, increased H2O2 production and elongated focal adhesions. Indeed, hyperglycaemic HUVECs were stiffer compared to normoglycaemic cells. PDI and pecPDI inhibition reversed the abovementioned processes in hyperglycaemic cells. A secretomics analysis revealed eight proteins secreted in a PDI-dependent manner by hyperglycaemic cells. Among these, we showed that genetic deletion of LAMC1 and SLC3A2 decreased platelet-endothelium interaction and did not potentiate the effects of PDI inhibitors. CONCLUSIONS: Endothelial pecPDI regulates platelet-endothelium interaction in hyperglycemia through adhesion-related proteins and alterations in endothelial membrane biophysics.
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BACKGROUND: Platelet contains growth factors that enhance tissue repair mechanisms, including epidermal growth factor (EGF), platelet-derived growth factor (PDGF-AA and -AB), and transforming growth factor (TGF)-ß. Autologous platelet-rich plasma (PRP) has been shown to significantly improve the treatment of tendon injuries compared with hyaluronic acid and placebo. The topic of agreement between platelet concentrations and growth factors has been covered in some previous studies, but growth factor levels did not correlate well with platelet concentrations. METHOD: In this study, autologous PRP was prepared by concentrating platelets through a J6-MI centrifuge. The automatic hematology analyzer Sysmex XN-20 was used to analyze the platelet concentration in PRP, and the PRP growth factors were determined by ELISA, including PDGF, transforming growth factor- ß1 (TGF-ß1), and EGF. Statistical analysis was conducted on data from 107 patients who received autologous PRP using Pearson correlation analysis. RESULTS: Pearson correlation analysis revealed PDGF, TGF, and EGF had a strong positive correlation with the platelet concentration of the final PRP product (râ¯=â¯0.697, pâ¯<â¯0.0001; râ¯=â¯0.488, pâ¯<â¯0.0001; râ¯=â¯0.572, pâ¯<â¯0.0001, respectively) CONCLUSIONS: There was a strong positive correlation between the concentration of platelets in the final PRP product and the levels of PDGF-AB, TGF-ß, and EGF. These results suggested straightforward and cost-effective growth factor tests can provide valuable information about platelet content in PRP.
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Background: Obesity and type 2 diabetes (T2D) pose global health problems that continue to rise. A chronic low-grade inflammation and activation of the immune system are well established in both conditions. The presence of these factors can predict disease development and progression. Emerging evidence suggests that platelet-high density lipoprotein ratio (PHR) is a potential inflammatory marker. The purpose of this study was to investigate the relationship between PHR and T2D among obese patients. Methods: 203 patients with BMI ≥ 30 kg/m2 participated in the study. Patients were categorized into two groups: non-diabetic obese and diabetic obese. Comorbidities, baseline characteristics, laboratory data, as well as PHR levels of the study groups were analyzed. Medians, risk assessment, and the diagnostic performance of PHR values were examined in both groups. Results: In obese patients, the median PHR were significantly increased in obese patients with T2D compared to non-diabetic obese (p < 0.0001). Furthermore, T2D obese with high PHR had a significantly higher FBG and HbA1c (p < 0.05). Although PHR was weakly yet significantly correlated with glycemic markers, ROC curve analysis of the PHR indicated an AUC of 0.700 (p < 0.0001) in predicting T2D in obese patients, and the cutoff value was 6.96, with a sensitivity and specificity of 53.4% and 76.1%, respectively. Moreover, increased PHR (OR = 4.77, p < 0.0001) carried a significantly higher risk for developing T2D in obese individuals. Conclusions: The PHR is a convenient and cost-effective marker that can reliably predict the presence of T2D in high-risk obese population.
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Platelet-fibrin clot formation is a key process in acute arterial thrombosis. The relationship between thrombin-induced platelet-fibrin clot strength (P-FCS) and fibrinogen levels in patients with cardiovascular disease (CVD) and COVID-19 has not been studied. In thhe current study, the contribution of fibrinogen to P-FCS has been explored in healthy subjects (n=157), patients hospitalized with COVID-19 (n=116), and patients with CVD (n=93) using thrombelastography (TEG 6s) with citrate cartridge. We found that thrombin-induced P-FCS, fibrin clot strength (F-CS) and fibrinogen levels (FLEV) were higher among patients with CVD and COVID-19 compared to HS (p<0,05 for all) and highest among patients with COVID-19. P-FCS, an established risk factor for post-PCI ischemic event occurrences, was associated with both F-CS and FLEV (R2=0.67, p<0.001 for both comparisons. These data indicate that fibrinogen levels strongly influence the viscoelastic strength of the platelet-fibrin clot, fibrinogen may be an important driving factor for arterial thrombosis in the presence of potent platelet inhibition and may be as equally important a risk factor as high platelet reactivity. Since P-FCS is significantly associated with fibrinogen levels, the role of fibrinogen as a risk factor for arterial ischemic event occurrences should be further studied to improve antithrombotic therapy personalization.
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BACKGROUND: Cutaneous melanoma (CM) is a malignancy with a variable incidence worldwide and a poor advanced-stage prognosis. Melanoma growth is closely associated with the immune system. METHODS: A cross-sectional study was performed on CM patients admitted at the Hospital de Cancer de Pernambuco (HCP) between 2015 and 2018. Fifty-one CM patients were included, and 30 healthy individuals. The study aimed to evaluate the association of platelet activation mechanisms and inflammatory response in patients with cutaneous melanoma. RESULTS: Elevated serum IL10 and low serum TNF levels in CM patients compared to controls (p < 0.05). High IL6 levels in patients with negative lymph nodes LN (-) compared to positive lymph nodes group (LN +, p = 0.0005). Low RANTES levels in patients compared to controls (p < 0.05). Elevated levels of platelet-lymphocyte (PLA), platelet-monocytes (PMA), and platelet-neutrophils (PNA) aggregates were observed in patients compared to controls (p < 0.05). CM patients with stage II had lower PMA levels than stages I and III (p < 0.05). High PMA levels were observed in patients with LN (+) compared to the LN (-) group (p < 0.0001). Patients with SSM had high levels of sCD40L and sCD62P compared to controls (p < 0.05)). High sCD40L levels in stage II compared to the stage III group, and sCD62P in stages I and II compared to the stage III group (p < 0.05). High sCD62P levels in patients with LN (-) compared to the group LN (+) (p < 0.05). CONCLUSION: It was observed the immunosuppressive profile in CM may favor tumor progression. High levels of platelet-leukocyte aggregates, sCD40L, and sCD62P may be associated with the worst prognosis.
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INTRODUCTION: We aimed to develop an automated, low-volume method for thrombocyte counting in capillary blood using the Sysmex predilution (PD) mode. METHODS: Microsamples were prepared by resuspension of 50 µL blood in 300 µL DCL CellPack. Thrombocyte counting was done in the impedance (PLT-I) and fluorescence (PLT-F) channels. The imprecision and bias was evaluated in >394 microsamples from adult blood. Preanalytical factors (skin-piercing, storage, and transportation in our pneumatic tube system) was assessed, and studies on pediatric microsamples were made for comparison. The improvement in analytical quality and turnaround time was examined. RESULTS: For PLT-F, the imprecision was 1.1%-3.7%, and the bias was 10.1% (95% CI: 8.8-11.3). After skin-piercing, the bias was 8.1% (95% CI: 5.6-10.6) and the imprecision 1.9% (95% CI: 1.3-2.5). Thrombocyte counts kept stable after 4 h at room temperature (94.8% [95% CI: 93.2-96.4]) and after pneumatic tube transportation [6.7% (95% CI: 4.8-8.6)]. The bias of the PD mode for pediatric microsamples was 13.0% (95% CI: -8.4-34.4) in the PLT-F channel. The automated method had a considerably lower imprecision than the existing manual thrombocyte counting method and reduced turnaround times. CONCLUSION: The automated microsample method offers a low-volume alternative for measurement of thrombocytes. The method appears useful also in pediatric samples.
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Clopidogrel remains the most widely used P2Y12 receptor inhibitor worldwide and is often used in combination with aspirin for secondary prevention in patients with arterial disease. The drug is associated with a wide response variability with one on three patients exhibiting little or no inhibition of adenosine diphosphate-induced platelet aggregation. It is a prodrug that is mainly metabolized by hepatic cytochrome P450 (CYP) 2C19. Patients who carry a CYP2C19 loss-of-function (LoF) allele have reduced metabolism of clopidogrel that is associated with reduced platelet inhibition compared to non-carriers that is associated with increased risk for thrombotic event occurrences, particularly, stent thrombosis. The United States Food and Drug Administration (US FDA) issued a black box warning in the clopidogrel label highlighting the importance of presence of CYP2C19 LOF allele during the insufficient metabolism of clopidogrel and availability of other potent P2Y12 inhibitor for the treatment in CYP2C19 poor metabolizers. Clinical trials have conclusively demonstrated greater anti-ischemic benefits of prasugrel/ticagrelor in the treatment of patients carrying the CYP2C19 LoF allele. However, uniform use of these more potent P2Y12 inhibitors has been associated with greater bleeding and cost, and lower adherence. The latter information provides a strong rationale for personalizing P2Y12 inhibitor therapy based on the laboratory determination of CYP2C19 genotype. However, cardiologists have been slow to take up pharmacogenetic testing possibly due to lack of provider and patient education, clear cardiology guidelines and, and lack of positive results from adequately sized randomized clinical trials. However, current evidence strongly supports genotyping of patients who are candidates for clopidogrel. Physicians should strongly consider performing genetic tests to identify LoF carriers and treat these patients with more pharmacodynamically predictable P2Y12 inhibitors than clopidogrel.
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BACKGROUND: This is the first study in which the impact of platelet transfusions on seven platelet indices was evaluated in platelet transfusion-dependent patients admitted in the ICU. STUDY DESIGN AND METHODS: Among a cohort of 21 ICU patients prospectively studied over eleven months, a total of 19 ICU patients were enrolled. Seven platelet indices were measured before and then, within 18-24 h, after platelet transfusions using the Sysmex XN-10 analyser and statistically investigated as follows: i) apheresis vs. pooled platelet transfusions; ii) pre- vs. post-platelet transfusions; and iii) platelet count (PC) increment vs. PC decrement group. RESULTS: A 79.2% of platelet transfusion episodes in ICU patients showed an increase in PC increment within 18-24 h, of which 73.7% had a peak percentage immature platelet fraction (%-IPF) above 10.0% during their stay. No difference was observed in the measurements of platelet indices between the apheresis and pooled platelet transfusion doses (all p > 0.05). Of the seven platelet indices investigated, plateletcrit (PCT) and absolute immature platelet count (A-IPF) were not influenced by platelet transfusions and thus proven to be stable (0.06 vs. 0.07%, p = 0.0901 and 4.6 vs. 4.9 × 109/L, p = 0.4559, respectively), despite their close proximity to platelet transfusion. But the overall effectiveness of these indices in detecting changes over time was not hindered. CONCLUSION: A-IPF and PCT are stable after platelet transfusions, regardless of whether patient's respond to or do not respond to platelet transfusion doses. PCT and A-IPF may thus prove useful in monitoring patient transfusion support and guiding management in thrombocytopenic patients.
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Previous research has revealed that platelets promote tumor metastasis by binding to circulating tumor cells (CTCs). However, the role of platelets in epithelial-mesenchymal transition (EMT) of cancer cells at the primary tumor site, the crucial initial step of tumor metastasis, remains to be elucidated. Here, we found that platelet releasate enhanced EMT and motility of hepatocellular carcinoma (HCC) cells via AMPK/mTOR-induced autophagy. RNA-seq indicated that platelet releasate altered TGF-ß signaling pathway of cancer cells. Inhibiting TGFBR or deleting platelet TGF-ß1 suppressed AMPK/mTOR pathway activation and autophagy induced by platelet releasate. Compared with Pf4cre-; Tgfb1fl/fl mice, HCC orthotopic models established on Pf4cre+; Tgfb1fl/fl mice showed reduced TGF-ß1 in primary tumors, which corresponded with decreased cancer cell EMT, autophagy, migration ability and tumor metastasis. Inhibition of autophagy via Atg5 knockdown in cancer cells negated EMT and metastasis induced by platelet-released TGF-ß1. Clinically, higher platelet count correlated with increased TGF-ß1, LC3 and N-cad expression in primary tumors of HCC patients, suggesting a link between platelets and HCC progression. Our study indicates that platelets promote cancer cell EMT in the primary tumor and HCC metastasis through TGF-ß1-induced HCC cell autophagy via the AMPK/mTOR pathway. These findings offer novel insights into the role of platelets in HCC metastasis and the potential therapeutic targets for HCC metastasis.