Large and small platelets-(When) do they differ?

Inflammation modifies the platelet reactivity among thrombocytopenia patients undergoing percutaneous coronary intervention

Percutaneous coronary intervention (PCI) patients combined with thrombocytopenia (TP) are usually considered to be at low ischemic risk, receiving less proper antiplatelet therapy. However, recent studies reported a paradoxical phenomenon that PCI patients with TP were prone to experience thrombotic events, while the mechanisms and future treatment remain unclear. We aim to investigate whether inflammation modifies platelet reactivity among these patients. Consecutive 10 724 patients undergoing PCI in Fuwai Hospital were enrolled throughout 2013. High-sensitivity C-reactive protein (hsCRP) ≥2 mg/L was considered inflammatory status. TP was defined as platelet count <150×109/L. High on-treatment platelet reactivity (HTPR) was defined as adenosine diphosphate-induced platelet maximum amplitude of thromboelastogram >47mm. Among 6617 patients finally included, 879 (13.3%) presented with TP. Multivariate logistic regression demonstrated that patients with TP were associated with a lower risk of HTPR (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.53-0.76) than those without TP in the overall cohort. In further analysis, among hsCRP <2 mg/L group, patients with TP exhibited a decreased risk of HTPR (OR 0.53, 95% CI 0.41-0.68); however, in hsCRP ≥2mg/L group, TP patients had a similar risk of HTPR as those without TP (OR 0.83, 95% CI 0.63-1.08). Additionally, these results remain consistent across subgroups, including patients presenting with acute coronary syndrome and chronic coronary syndrome. Inflammation modified the platelet reactivity of PCI patients with TP, providing new insights into the mechanisms of the increased thrombotic risk. Future management for this special population should pay more attention to inflammation status and timely adjustment of antiplatelet therapy in TP patients with inflammation.

An Investigation of Size Distribution and Calcium Signaling in Human Platelets

Background Platelets are thin disc-shaped blood cells that play a major role in hemostasis, maintenance of vascular integrity, and blood coagulation. Large platelets are more reactive and seen in patients with cardiovascular disease. This study aims to analyze the changes in platelet size of ex vivo activated platelets which phenotypically simulates that of a patient at risk of cardiovascular disease and elucidate the calcium signaling pathway responsible for this change. Methodology Platelets were isolated from adult human blood by differential centrifugation. Calcium was mobilized into platelets by treatment with calcium ionophore A23187 in the presence of Ca2+. Platelet size distribution was analyzed using Coulter Counter Multisizer 4. The following signaling parameters were studied: intracellular Ca2+ measurement (using Fura-2/AM by fluorescence spectrophotometry), Ca2+-dependent thiol protease calpain assay (using fluorogenic substrate t-butoxycarbonyl-Leu-metchloromethylcoumarin in fluorescence microplate reader), platelet-derived microparticles (using FACS Calibur flow cytometry), and cytoskeletal protein talin expression (by western immunoblotting). Results When adult platelets were treated with A23187 and Ca2+, two subcellular populations (<2 µm and between 2-4 µm) were noted. The mean size of the second cell population was significantly higher than that of resting platelets (2.94 ± 0.13 µm vs. 2.82 ± 0.15 µm, t = 4.605, p = 0.00). A23187 treatment led to elevated intracellular Ca2+, release of platelet-derived microparticles, increase in calpain activity, and cytoskeletal talin degradation. These events were inhibited by calpeptin (a specific calpain inhibitor). Conclusions Elevated calcium caused talin degradation by calpain activity. Breakdown of this cytoskeletal protein leads to relative swelling of cells reflected by the increase in platelet size.

Association between Platelet-Derived Growth Factor Receptor Alpha Gene Polymorphisms and Platelet-Rich Plasma's Efficiency in Treating Lateral Elbow Tendinopathy-A Prospective Cohort Study

Individual differences in the response to platelet-rich plasma (PRP) therapy can be observed among patients. The genetic background may be the cause of this variability. The current study focused on the impact of genetic variants on the effectiveness of PRP. The aim of the present study was to analyze the impact of single nucleotide polymorphisms (SNP) of the platelet-derived growth factor receptor alpha (PDGFRA) gene on the effectiveness of treating lateral elbow tendinopathy (LET) with PRP. The treatment's efficacy was analyzed over time (2, 4, 8, 12, 24, 52 and 104 weeks after the PRP injection) on 107 patients using patient-reported outcome measures (PROM) and achievement of a minimal clinically important difference (MCID). Four SNPs of the PDGFRA gene (rs7668190, rs6554164, rs869978 and rs1316926) were genotyped using the TaqMan assay method. Patients with the AA genotypes of the rs7668190 and the rs1316926 polymorphisms, as well as carriers of the T allele of rs6554164 showed greater effectiveness of PRP therapy than carriers of other genotypes. Moreover, the studied SNPs influenced the platelets' parameters both in whole blood and in PRP. These results showed that PDGFRA gene polymorphisms affect the effectiveness of PRP treatment. Genotyping the rs6554164 and the rs1316926 SNPs may be considered for use in individualized patient selection for PRP therapy.

A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children

Mycoplasma pneumoniae pneumonia (MPP) is usually mild and self-limiting, but still about 12% of them will progress to severe Mycoplasma pneumoniae pneumonia (SMPP), which have poor survival rates and often require intensive medical resource utilization. We retrospectively collected clinical data from 526 children with MPP admitted to the Children's Hospital Affiliated to Zhengzhou University from June 2018 to February 2023 and randomly divided the data into a training cohort and a validation cohort at a ratio of 4:1. Univariate and multivariate logistic regressions were used to identify independent risk factors for SMPP. Age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze are independent risk factors for SMPP in children. Then, we built an online dynamic nomogram ( https://ertongyiyuanliexiantu.shinyapps.io/SMPP/ ) based on the 11 independent risk factors. The C-index, ROC curve, DCA curve and calibration curve were used to assess the performance of the nomogram, which all showed that the dynamic nomogram has excellent clinical value. Based on age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze, the first dynamic nomogram for accurately predicting SMPP was successfully established.

Cost-effective prognostic evaluation of breast cancer: using a STAR nomogram model based on routine blood tests

Background

Breast cancer (BC) is the most common and prominent deadly disease among women. Predicting BC survival mainly relies on TNM staging, molecular profiling and imaging, hampered by subjectivity and expenses. This study aimed to establish an economical and reliable model using the most common preoperative routine blood tests (RT) data for survival and surveillance strategy management.

Methods

We examined 2863 BC patients, dividing them into training and validation cohorts (7:3). We collected demographic features, pathomics characteristics and preoperative 24-item RT data. BC risk factors were identified through Cox regression, and a predictive nomogram was established. Its performance was assessed using C-index, area under curves (AUC), calibration curve and decision curve analysis. Kaplan-Meier curves stratified patients into different risk groups. We further compared the STAR model (utilizing HE and RT methodologies) with alternative nomograms grounded in molecular profiling (employing second-generation short-read sequencing methodologies) and imaging (utilizing PET-CT methodologies).

Results

The STAR nomogram, incorporating subtype, TNM stage, age and preoperative RT data (LYM, LYM%, EOSO%, RDW-SD, P-LCR), achieved a C-index of 0.828 in the training cohort and impressive AUCs (0.847, 0.823 and 0.780) for 3-, 5- and 7-year OS rates, outperforming other nomograms. The validation cohort showed similar impressive results. The nomogram calculates a patient's total score by assigning values to each risk factor, higher scores indicating a poor prognosis. STAR promises potential cost savings by enabling less intensive surveillance in around 90% of BC patients. Compared to nomograms based on molecular profiling and imaging, STAR presents a more cost-effective, with potential savings of approximately $700-800 per breast cancer patient.

Conclusion

Combining appropriate RT parameters, STAR nomogram could help in the detection of patient anemia, coagulation function, inflammation and immune status. Practical implementation of the STAR nomogram in a clinical setting is feasible, and its potential clinical impact lies in its ability to provide an early, economical and reliable tool for survival prediction and surveillance strategy management. However, our model still has limitations and requires external data validation. In subsequent studies, we plan to mitigate the potential impact on model robustness by further updating and adjusting the data and model.

Separation of platelets by size in a microfluidic device based on controlled incremental filtration

The significant biological and functional differences between small and large platelets suggested by recent studies could have profound implications for transfusion medicine. However, investigating the relationship between platelet size and function is challenging because separating platelets by size without affecting their properties is difficult. A standard approach is centrifugation, but it inevitably leads to premature activation and aggregation of separated platelets. This paper describes the development and validation of a microfluidic device based on controlled incremental filtration (CIF) for separating platelets by size without the cell damage and usability limitations associated with centrifugation. Platelet samples derived from whole blood were used to evaluate the dependence of the CIF device separation performance on design parameters and flow rate, and to compare the properties of PLT fractions generated by the CIF device with those produced using a centrifugation protocol in a split-sample study. This was accomplished by quantifying the platelet size distribution, mean platelet volume (MPV), platelet-large cell ratio (P-LCR) and platelet activation before and after processing for all input and output samples. The 'large platelet' fractions produced by the CIF device and the centrifugation protocol were essentially equivalent (no significant difference in MPV and P-LCR). Platelets in the 'small platelet' fraction produced by the CIF device were significantly smaller than those produced by centrifugation (lower MPV and P-LCR). This was because the CIF 'small platelet' fraction was contaminated by much fewer large platelets (∼2-times lower recovery of >12 fL platelets) and retained the smallest platelets that were discarded by the centrifugation protocol. There was no significant difference in platelet activation between the two methods. However, centrifugation required a substantial amount of additional anticoagulant to prevent platelet aggregation during pelleting. Unlike centrifugation, the CIF device offered continuous, flow-through, single-step processing that did not cause platelet aggregation. Such a capability has the potential to accelerate the basic studies of the relationship between platelet size and function, and ultimately improve transfusion practice, particularly in the pediatric setting, where the need for low-volume, high-quality platelet transfusions is most urgent.

Canine diabetes mellitus demonstrates multiple markers of chronic inflammation including Th40 cell increases and elevated systemic-immune inflammation index, consistent with autoimmune dysregulation

Introduction

Canine diabetes mellitus (CDM) is a relatively common endocrine disease in dogs. Many CDM clinical features resemble human type 1 diabetes mellitus (T1DM), but lack of autoimmune biomarkers makes calling the disease autoimmune controversial. Autoimmune biomarkers linking CDM and T1DM would create an alternative model for drug development impacting both human and canine disease.

Methods

We examined peripheral blood of diagnosed CDM dog patients comparing it to healthy control (HC) dogs. Dogs were recruited to a study at the Colorado State University Veterinary Teaching Hospital and blood samples collected for blood chemistry panels, complete blood counts (CBC), and immunologic analysis. Markers of disease progression such as glycated albumin (fructosamine, the canine equivalent of human HbA1c) and c-peptide were addressed.

Results

Significant differences in adaptive immune lymphocytes, innate immune macrophages/monocytes and neutrophils and differences in platelets were detected between CDM and HC based on CBC. Significant differences in serum glucose, cholesterol and the liver function enzyme alkaline phosphatase were also detected. A systemic immune inflammation index (SII) and chronic inflammation index (CII) as measures of dynamic changes in adaptive and innate cells between inflammatory and non-inflammatory conditions were created with highly significant differences between CDM and HC. Th40 cells (CD4+CD40+ T cells) that are demonstrably pathogenic in mouse T1DM and able to differentiate diabetic from non-diabetic subjects in human T1DM were significantly expanded in peripheral blood mononuclear cells.

Conclusions

Based on each clinical finding, CDM can be categorized as an autoimmune condition. The association of significantly elevated Th40 cells in CDM when compared to HC or to osteoarthritis, a chronic but non-autoimmune disease, suggests peripheral blood Th40 cell numbers as a biomarker that reflects CDM chronic inflammation. The differences in SII and CII further underscore those findings.

Therapeutic and Diagnostic Agents based on Bioactive Endogenous and Exogenous Coordination Compounds

Metal-based coordination compounds have very special place in bioinorganic chemistry because of their different structural arrangements and significant application in medicine. Rapid progress in this field increasingly enables the targeted design and synthesis of metal-based pharmaceutical agents that fulfill valuable roles as diagnostic or therapeutic agents. Various coordination compounds have important biological functions, both those initially present in the body (endogenous) and those entering the organisms from the external environment (exogenous): vitamins, drugs, toxic substances, etc. In the therapeutic and diagnostic practice, both the essential for all living organisms and the trace metals are used in metal-containing coordination compounds. In the current review, the most important functional biologically active compounds were classified group by group according to the position of the elements in the periodic table.

Addressing thrombosis concerns in immune thrombocytopenia: the role of fostamatinib in immune thrombocytopenia management

INTRODUCTION

Immune thrombocytopenia (ITP), a disease that commonly presents with an increased risk of bleeding, can also paradoxically produce an increased risk of thromboembolic events. The risk of thromboembolism can be associated with patient-related factors (e.g. co-morbidities, age and history of thrombosis), disease-related factors (e.g. a greater proportion of younger, more reactive platelets, and the presence of microparticles and pro-inflammatory cytokines) and treatment-related factors (e.g. splenectomy, thrombopoietin receptor agonists, and IVIg).

AREAS COVERED

Aspects of the pathophysiology of ITP and the effects of treatment are discussed with emphasis on individualizing treatment based on the patient's thromboembolic risk, treatment options and preferences.

EXPERT OPINION

An increased understanding of the pathophysiology of ITP has led to the development of new agents such as fostamatinib, a spleen tyrosine kinase inhibitor. Further research into the factors contributing to the risks for bleeding and thromboembolic events can contribute to the development of more specific therapies for ITP and allow greater individualization of therapy based on each patient's medical history and clinical status.

Apoptosis is one cause of thrombocytopenia in patients with high-altitude polycythemia

High-altitude polycythemia (HAPC) can occur in individuals who are intolerant to high-altitude hypoxia. In patients with HAPC, erythrocytosis is often accompanied by a decrease in platelet count. Chronic hypoxia can increase the incidence of arteriovenous thrombosis and the risk of bleeding during antithrombotic treatment due to thrombocytopenia; therefore, understanding the cause of thrombocytopenia can reduce the risk of treatment-related bleeding. In this study, we examined platelet production and apoptosis to understand the cause of thrombocytopenia in patients with HAPC. The classification of myeloid-derived megakaryocytes (MKs) in HAPC patients was mainly granular MKs rather than mature MKs, suggesting impaired differentiation and maturation. However, the total number of MKs and newly generated reticulated platelets in the peripheral blood increased, indicating sufficient platelet generation in HAPC thrombocytopenia. Increased platelet apoptosis may be one of the causes of thrombocytopenia. Platelet activation and GP1bα pathway activation induced by thrombin and von Willebrand factor can lead to platelet apoptosis. Platelet production was not reduced in patients with HAPC, whereas platelet apoptosis was associated with thrombocytopenia. These findings provide a rationale for considering the bleeding risk in HAPC patient while treating thrombotic diseases.

Double-edged functions of hemopexin in hematological related diseases: from basic mechanisms to clinical application

It is now understood that hemolysis and the subsequent release of heme into circulation play a critical role in driving the progression of various diseases. Hemopexin (HPX), a heme-binding protein with the highest affinity for heme in plasma, serves as an effective antagonist against heme toxicity resulting from severe acute or chronic hemolysis. In the present study, changes in HPX concentration were characterized at different stages of hemolytic diseases, underscoring its potential as a biomarker for assessing disease progression and prognosis. In many heme overload-driven conditions, such as sickle cell disease, transfusion-induced hemolysis, and sepsis, endogenous HPX levels are often insufficient to provide protection. Consequently, there is growing interest in developing HPX therapeutics to mitigate toxic heme exposure. Strategies include HPX supplementation when endogenous levels are depleted and enhancing HPX's functionality through modifications, offering a potent defense against heme toxicity. It is worth noting that HPX may also exert deleterious effects under certain circumstances. This review aims to provide a comprehensive overview of HPX's roles in the progression and prognosis of hematological diseases. It highlights HPX-based clinical therapies for different hematological disorders, discusses advancements in HPX production and modification technologies, and offers a theoretical basis for the clinical application of HPX.

New insights into the glycobiology of immune thrombocytopenia

PURPOSE OF REVIEW

The platelet surface harbors a lush forest of glycans (carbohydrate polymers) attached to membrane proteins and lipids. Accumulating evidence suggests that these glycans may be relevant to the pathophysiology of immune thrombocytopenia (ITP). Here, we critically evaluate data that point to a possible role for loss of sialic acid in driving platelet clearance in ITP, comment on the potential use of neuraminidase inhibitors for treatment of ITP, and highlight open questions in this area.

RECENT FINDINGS

Multiple lines of evidence suggest a role for loss of platelet sialic acid in the pathophysiology of thrombocytopenia. Recent work has tested the hypothesis that neuraminidase-mediated cleavage of platelet sialic acid may trigger clearance of platelets in ITP. Some clinical evidence supports efficacy of the viral neuraminidase inhibitor oseltamivir in ITP, which is surprising given its lack of activity against human neuraminidases.

SUMMARY

Further study of platelet glycobiology in ITP is necessary to fill key knowledge gaps. A deeper understanding of the roles of platelet glycans in ITP pathophysiology will help to guide development of novel therapies.

Combined effect of high factor VIII levels and high mean platelet volume on the risk of future incident venous thromboembolism

BACKGROUND

High factor VIII (FVIII) levels and large platelets, as reflected by a high mean platelet volume (MPV), are separately associated with increased risk of venous thromboembolism (VTE). Whether the combination of high FVIII levels and large platelets has a supra-additive effect on VTE risk is unknown.

OBJECTIVES

We aimed to investigate the joint effect of high FVIII levels and large platelets, as reflected by high MPV, on the risk of future incident VTE.

METHODS

A population-based nested case-control study with 365 incident VTE cases and 710 controls was derived from the Tromsø study. FVIII antigen levels and MPV were measured in blood samples drawn at baseline. Odds ratios with 95% CIs were estimated across FVIII tertiles (<85%, 85%-108%, and ≥108%) and within predefined MPV strata (<8.5, 8.5-9.5, and ≥9.5 fL).

RESULTS

VTE risk increased linearly across FVIII tertiles (Ptrend < .001) in models adjusted for age, sex, body mass index, and C-reactive protein. In the combined analysis, participants with FVIII levels in the highest tertile and an MPV of ≥9.5 fL (ie, joint exposure) had an odds ratio for VTE of 2.71 (95% CI, 1.44-5.11) compared with those with FVIII levels in the lowest tertile and an MPV of <8.5 fL (reference). In the joint exposure group, 52% (95% CI, 17%-88%) of VTEs were attributable to the biological interaction between FVIII and MPV.

CONCLUSION

Our results suggest that large platelets, as reflected by high MPV, might play a role in the mechanism by which high FVIII level increases the risk of incident VTE.

Hematologic setpoints are a stable and patient-specific deep phenotype

The complete blood count is an important screening tool for healthy adults and is the most commonly ordered test at periodic physical exams. However, results are usually interpreted relative to one-size-fits-all reference intervals, undermining the goal of precision medicine to tailor medical care to the needs of individual patients based on their unique characteristics. Here we show that standard complete blood count indices in healthy adults have robust homeostatic setpoints that are patient-specific and stable, with the typical healthy adult's set of 9 blood count setpoints distinguishable from 98% of others, and with these differences persisting for decades. These setpoints reflect a deep physiologic phenotype, enabling improved detection of both acquired and genetic determinants of hematologic regulation, including discovery of multiple novel loci via GWAS analyses. Patient-specific reference intervals derived from setpoints enable more accurate personalized risk assessment, and the setpoints themselves are significantly correlated with mortality risk, providing new opportunities to enhance patient-specific screening and early intervention. This study shows complete blood count setpoints are sufficiently stable and patient-specific to help realize the promise of precision medicine for healthy adults.

Platelet indices in overweight and obese children

The aim of the study was to determine the association between platelet indices and obesity in children. A total of 190 overweight or obese children (mean age: 13.29 ± 2.54, M/F: 0.74) and 100 normal-weight children (mean age: 12.72 ± 2.23, M/F:1.04) were enrolled in the study. Platelet count (PLT), platelet indices, and ratios were determined. No significant difference was observed in terms of mean platelet volume (MPV) and platelet distribution width (PDW) levels and MPV/plateletcrit (PCT) and PDW/PCT ratios between overweight, obese, and normal-weight groups, whereas significant differences were observed in terms of PLT, PCT, MPV/PLT, and PDW/PLT ratios between each group. PLT and PCT levels were significantly higher in the obese group than in the overweight and normal-weight groups (P = 0.003, P = 0.002, respectively). Children with obesity had lower MPV/PLT and PDW/PLT ratios than the other groups (P = 0.001, P = 0.02, respectively). Overweight and obese children with insulin resistance (IR) had higher PLT and lower MPV/PLT, and PDW/PLT ratios than the children without IR (P = 0.034, P = 0.04, P = 0.013, respectively).

CONCLUSION

Significant differences were observed in terms of PLT, PCT, MPV/PLT, and PDW/PLT between overweight, obese, and normal-weight children.

WHAT IS KNOWN

• Obesity is associated with a chronic low-grade systemic inflammation. • Platelets play a crucial role in coagulation, hemostasis, thrombosis, immunomodulatory processes, inflammation, and atherothrombosis.

WHAT IS NEW

• Significant differences were observed in terms of PLT, PCT, MPV/PLT, and PDW/PLT between overweight, obese, and normal-weight children. • Overweight and obese children with insulin resistance had higher PLT and lower MPV/PLT and PDW/PLT ratios than the children without insülin resistance.

Preliminary Study of sCD14 and sCD163 as Predictors of Disease Severity and ICU Admission in COVID-19: Relation to Hematological Parameters, Blood Morphological Changes and Inflammatory Biomarkers

Background and Objectives

Research supports the role of monocyte/macrophage activation in COVID-19 immunopathology. This study aimed to evaluate sCD14 and sCD163 - the monocyte activation markers - and to investigate their relation to hematological parameters and blood morphology in COVID-19 infection.

Methods

This is a case-control study that included 70 COVID-19 patients. Patients were subdivided into two groups: 23 severely diseased ICU-admitted patients and another group of 47 non-ICU-admitted patients. sCD163 and sCD14 levels were determined using ELISA.

Results

sCD163 and sCD14 showed significantly higher levels in sera of patients compared to the control group, with significantly higher levels of sCD163 in ICU-admitted patients than non-ICU admitted patients. Receiver operating characteristic curve analysis demonstrated the usefulness of sCD163 with a cut-off value of 734 ng/mL as a potential marker to discriminate between ICU and non-ICU admitted COVID-19 patients (sensitivity of 81.16%; specificity of 96.67% and positive predictive value of 98% with area under the curve of 0.930). sCD163 levels showed a positive correlation with total white blood cells, absolute neutrophilic count, Neutrophil/Lymphocyte ratio, and a negative correlation with platelet count. sCD14 levels positively correlated with D-dimer values associated with a shift to the left and neutrophilic toxic granulations in blood morphology.

Conclusion

High sCD163 and sCD14 levels, hematological parameters, and blood morphology reflect monocyte activation in COVID-19 infection. sCD163 is a potential marker of disease severity. These findings support further study of therapeutics targeting macrophage activity in COVID-19 patients with high sCD163 levels.

Chronic spontaneous urticaria: a low-grade disseminated intravascular coagulation only partially reversed by Omalizumab

Chronic spontaneous urticaria (CSU) is a disorder characterized by wheals and/or angioedema. The coagulation cascade and inflammation pathways are closely linked together. The aim of our study was first to investigate the dynamics of clot formation in plasma (Clot Waveform Analysis, CWA) in a group of 47 patients with CSU along with other coagulative parameters dedicated to the study of hypercoagulability, such as D-Dimer, F 1 + 2 peptide, Fibrinogen, Platelet count and Mean Platelet Volume (MPV). Secondly, 23 out of 47 patients were treated with Omalizumab at four administration intervals from T0 to T4. A statistically significant increase in Activated Partial Thromboplastin (aPTT) ratio, D-Dimer, F1 + 2, Platelet count and MPV was found when compared with 53 healthy controls (HC). In contrast, the 2nd Derivative of aPTT showed lower values than those of the HC. No differences were found between 1st derivative of aPTT and Fibrinogen. D-Dimer only showed a significant difference between T0 and T3. An activation of both coagulation and fibrinolysis along with a weaker clot acceleration may be in agreement with a low-grade DIC. The accelerated turnover of platelets expressed by both an increase in platelet count and MPV further supports this pathway in CSU. Omalizumab does not affect the relationship between the immune and the hemostatic systems.

Standardization of Animal Models and Techniques for Platelet-Rich Fibrin Production: A Narrative Review and Guideline

Experimental research is critical for advancing medical knowledge and enhancing patient outcomes, including in vitro and in vivo preclinical assessments. Platelet-rich fibrin (PRF) is a blood by-product that has garnered attention in the medical and dental fields due to its potential for tissue regeneration and wound healing. Animal models, such as rabbits and rats, have been used to produce PRF and examine its properties and applications. PRF has demonstrated potential in the dental and medical fields for reducing inflammation, promoting tissue repair, and accelerating wound healing. This narrative review aims to compare existing evidence and provide guidelines for PRF animal research, emphasizing the importance of standardizing animal models, following ethical considerations, and maintaining transparency and accountability. The authors highlight the necessity to use the correct relative centrifugal force (RCF), standardize centrifugal calibration, and report detailed information about blood collection and centrifuge parameters for reproducible results. Standardizing animal models and techniques is crucial for narrowing the gap between laboratory research and clinical applications, ultimately enhancing the translation of findings from bench to bedside.

Relation of Mean Platelet Volume (MPV) with Cancer: A Systematic Review with a Focus on Disease Outcome on Twelve Types of Cancer

Inflammatory proteins activate platelets, which have been observed to be directly related to cancer progression and development. The aim of this systematic review is to investigate the possible association between Mean Platelet Volume (MPV) and cancer (diagnostic capacity of MPV, relation to survival, the severity of the disease, and metastasis). A literature review was performed in the online database PubMed and Google Scholar for the period of 2010–2022. In total, 83 studies including 21,034 participants with 12 different types of cancer (i.e., gastric cancer, colon cancer, esophageal squamous cell carcinoma, renal cancer, breast cancer, ovarian cancer, endometrial cancer, thyroid cancer, lung cancer, bladder cancer, gallbladder cancer, and multiple myeloma) were identified. The role of MPV has been extensively investigated in several types of cancer, such as gastric, colon, breast, and lung cancer, while few data exist for other types, such as renal, gallbladder cancer, and multiple myeloma. Most studies in gastric, breast, endometrium, thyroid, and lung cancer documented an elevated MPV in cancer patients. Data were less clear-cut for esophageal, ovarian, and colon cancer, while reduced MPV was observed in renal cell carcinoma and gallbladder cancer. Several studies on colon cancer (4 out of 6) and fewer on lung cancer (4 out of 10) indicated an unfavorable role of increased MPV regarding mortality. As far as other cancer types are concerned, fewer studies were conducted. MPV can be used as a potential biomarker in cancer diagnosis and could be a useful tool for the optimization of treatment strategies. Possible underlying mechanisms between cancer and MPV are discussed. However, further studies are needed to elucidate the exact role of MPV in cancer progression and metastasis.

Laboratory Markers of Platelet Production and Turnover

Platelets are formed from bone marrow megakaryocytes, circulate in blood for 7-10 days, and then are destroyed in the spleen and/or liver. Platelet production depends on the megakaryocyte population state in the bone marrow: number and size of the cells. The platelet turnover, i.e., the number of platelets passing through the bloodstream in a certain time, is determined by both the rate of their production and the rate of their destruction. The review considers laboratory markers, which are used to assess platelet production and turnover in the patients with hematologic and cardiovascular pathologies. These markers include some characteristics of platelets themselves: (i) content of reticulated ("young") forms in the blood detected by their staining with RNA dyes; (ii) indicators of the platelet size determined in hematology analyzers (mean volume, percentage of large forms) and in flow cytometers (light scattering level). Alterations of platelet production and turnover lead to the changes in blood plasma concentrations of such molecules as thrombopoietin (TPO, main mediator of megakaryocyte maturation and platelet formation in the bone marrow) and glycocalicin (soluble fragment of the membrane glycoprotein Ib detached from the surface of platelets during their destruction). Specific changes in the markers of platelet production and turnover have been observed in: (i) hypoproductive thrombocytopenias caused by suppression of megakaryocytes in the bone marrow; (ii) immune thrombocytopenias caused by accelerated clearance of the autoantibody-sensitized platelets; and (iii) thrombocytosis (both primary and reactive). The paper presents the data indicating that in patients with cardiovascular diseases an increased platelet turnover and changes in the corresponding markers (platelet size indexes and content of reticulated forms) are associated with the decreased efficacy of antiplatelet drugs and increased risk of thrombotic events, myocardial infarction, and unstable angina (acute coronary syndrome).

Identification of Pulmonary Hypertension Animal Models Using a New Evolutionary Machine Learning Framework Based on Blood Routine Indicators

Pulmonary Hypertension (PH) is a global health problem that affects about 1% of the global population. Animal models of PH play a vital role in unraveling the pathophysiological mechanisms of the disease. The present study proposes a Kernel Extreme Learning Machine (KELM) model based on an improved Whale Optimization Algorithm (WOA) for predicting PH mouse models. The experimental results showed that the selected blood indicators, including Haemoglobin (HGB), Hematocrit (HCT), Mean, Platelet Volume (MPV), Platelet distribution width (PDW), and Platelet-Large Cell Ratio (P-LCR), were essential for identifying PH mouse models using the feature selection method proposed in this paper. Remarkably, the method achieved 100.0% accuracy and 100.0% specificity in classification, demonstrating that our method has great potential to be used for evaluating and identifying mouse PH models.

Abnormal platelet immunophenotypes and percentage of giant platelets in myelodysplastic syndrome: A pilot study

OBJECTIVES

Myelodysplastic syndrome (MDS) is a heterogeneous hematopoietic stem cell disorder with thrombocytopenia. Flow cytometric immunophenotyping of blood cells has been instrumental in diagnosis as co-criteria, but the data regarding platelets remains lacking. This study aims to determine if there is a difference in surface antigen levels on platelets by comparing surface antigen levels in MDS patients and healthy control subjects. Concurrently, as flow cytometric gating can reveal the diameter of cells, this study will investigate differences in giant platelet percentage by comparing these percentages in high- and low-risk MDS patients.

STUDY DESIGN

Twenty newly diagnosed MDS patients were enrolled in this study. Platelet surface antigen levels were determined by measuring the binding capacity of antibodies with flow cytometry.

RESULTS

Platelets of MDS patients were shown to have a lower level of CD61 and higher levels of CD31 and CD36 than healthy controls. Judged by forward scatter (FSC), MDS patients' platelets appeared to be larger than those of healthy control subjects, whereas the MFI adjusted by diameter (MFI/FSC ratio) of CD31, CD41a, CD42a, CD42b and CD61 on platelets were lower in MDS patients than in healthy control subjects. There was a significant quantity of giant platelets found in MDS patients, and the high-risk MDS patients tended to have a higher percentage of giant platelets than low-risk patients. Conclusions: All the results indicate that MDS patients exhibit a lower antigen presentation (MFI) adjusted by diameter on platelets than healthy controls and the giant platelets detected by flow cytometry might correlate with the condition of MDS.

Scoping Review on Platelets and Tumor Angiogenesis: Do We Need More Evidence or Better Analysis?

Platelets are an active component of the tumor microenvironment (TME), involved in the regulation of multiple tumor processes, including angiogenesis. They are generated rich in angiogenic factors in their granules to actively participate in the hemostatic process by megakaryocytes and further enriched in angiogenic factors by all components of the tumor microenvironment to control the angiogenic process because of their preferential relationship with the endothelial component of vessels. In recent decades, the literature has reported a great deal of evidence on the role of platelets in tumor angiogenesis; however, it is unclear whether the number or mean volume of platelets and/or their content and localization in TME may have clinical relevance in the choice and management of therapy for the cancer patient. In this scoping review, we collected and critically reviewed the scientific evidence supporting a close relationship between platelets, cancer, and angiogenesis. The aim of this work was to define the landscape of platelet-activated angiogenesis in cancer progression and analyze what and how much evidence is present in the last 20 years in the literature at both the preclinical and clinical levels, to answer whether platelets could be a useful determinant for analyzing tumor angiogenesis. In conclusion, this scoping review indicates that there is much evidence, both preclinical and clinical, but in the preclinical context, studies demonstrate the direct involvement of platelets in tumor angiogenesis; in the clinical context the evidence is indirect, though strong, and the indication of how and to what extent platelet content contributes to tumor angiogenesis is lacking. So, do we need more evidence or better analysis? More molecular and quali-quantitative data is needed to translate the results obtained in preclinical studies into the clinical setting. This information about platelets, if correlated with tumor type and its biology, including tumor vasculature, type of angiogenesis, and patient characteristics (age, sex, comorbidities, drug treatments for chronic diseases) could be an important pa- rameter for correlating platelet biology to angiogenesis, for personalizing cancer therapy, and for clinical prognosis.

Platelet-Derived Biomarkers: Potential Role in Early Pediatric Serious Bacterial Infection and Sepsis Diagnostics

Fever is the most common complaint of children who are attending a pediatric emergency department (PED). Most of the fever cases are of viral origin; however, the most common markers, such as leucocyte, neutrophil count, or C-reactive protein, are not sensitive or specific enough to distinguish the etiology of fever, especially if children present at the early phase of infection. Currently, platelets have been attributed a role as important sentinels in viral and bacterial infection pathogenesis. Thus, our aim was to analyze different platelet indices, such as PNLR (platelet-to-neutrophil/lymphocyte ratio), PNR (platelet-to-neutrophil ratio) as well as specific secreted proteins, such as sP-selectin, CXCL4, CXCL7, and serotonin. We included 68 children who were referred to PED with the early onset of fever (<12 h). All children with comorbidities, older than five years, and psychiatric diseases, who refused to participate were excluded. All the participants were divided into viral, bacterial, or serious bacterial infection (SBI) groups. All the children underwent blood sampling, and an additional sample was collected for protein analysis. Our analysis revealed statistically significant differences between leucocyte, neutrophil, and CRP levels between SBI and other groups. However, leucocyte and neutrophil counts were within the age norms. A higher PNLR value was observed in a bacterial group, PNR-in viral. As we tested CXCL7 and sP-selectin, alone and together those markers were statistically significant to discriminate SBI and sepsis from other causes of infection. Together with tachypnoe and SpO2 < 94%, it improved the prediction value of sepsis as well as SBI. CXCL4 and serotonin did not differ between the groups. Concluding, CXCL7 and sP-selectin showed promising results in early SBI and sepsis diagnosis.

Effects of acute inflammation on platelet indices: An experimental study

Background and objective: It is well known that inflammation may affect the platelets. However, there are inconsistencies between the results of observational studies investigating changes in platelet indices in inflammatory conditions. This study aimed to investigate the possible effects of acute inflammation on platelet indices in plantar inflammation model in rats. Methods: A total of 10 rats, 5 in each group, were used in the study. Lambda-carrageenan and saline were applied subcutaneously to the right hind paw of the rats in the inflammation group and in the control group, respectively. Six hours after the administration, blood samples were taken from femoral arteries and femoral veins, and platelet indices were measured by a hematology analyzer. In addition, plantar tissue samples belonging to the control and inflammation groups were evaluated histopathologically. Results: On histopathological examination, no pathological condition was observed in the control group, while there were changes consistent with acute inflammation in the lambda-carrageenan-injected group. There was no significant difference in terms of platelet indices between both the arterial and vein samples and between the control and inflammation groups. Conclusions: Our results suggest that platelet indices cannot be used in the diagnosis of acute inflammatory conditions. However, in our opinion, these findings must not be interpreted as that acute inflammation does not affect platelet number and volume. Instead, we believe that it may be more appropriate to say that acute inflammation does not produce a quantitatively significant change in platelet indices due to the combination of the opposite effects.

Ortalama trombosit hacmi ve ortalama trombosit hacmi/trombosit sayısı oranının periton diyalizi başlandıktan bir yıl sonraki değişimi

Aim: Cardiovascular diseases are the most common cause of mortality in patients undergoing peritoneal dialysis. Thrombocyte indices which are indicators of platelet activation are predictors of cardiovascular events. We aim to examine the change in platelet count, mean platelet volume, and mean platelet volume to platelet count ratio one year after initiation of peritoneal dialysis in patients with end-stage renal disease. Materials and Methods: This retrospective study included 28 patients. Demographic and clinical characteristics of the patients at the time of initiation of peritoneal dialysis were recorded from the patient files. Laboratory data within the last month before the initiation of peritoneal dialysis and in the first year were recorded from the patient files. The mean platelet volume to platelet count ratio was calculated as mean platelet volume (femtolitres) divided by platelet count (number of thousand platelets/microliter). Results: The mean age was 51.1 ± 14.6 years, and 42.8% of the patients were male. Diabetic nephropathy and hypertensive nephropathy were the most common causes of end-stage renal disease. One year after the initiation of peritoneal dialysis, the urea level decreased significantly, and C-reactive protein level increased significantly. Platelet count increased from 240 ± 55 x10 3 /μL to 274 ± 53 x10 3 /μL (p=0.003) and mean platelet volume decreased from 10.7 ± 1.0 fl to 10.2 ± 0.8 fl (p

Platelets control liver tumor growth through P2Y12-dependent CD40L release in NAFLD

Platelets, the often-overlooked component of the immune system, have been shown to promote tumor growth. Non-alcoholic fatty liver disease (NAFLD) is a common disease in the Western world and rising risk for hepatocellular carcinoma (HCC). Unexpectedly, we observed that platelets can inhibit the growth of established HCC in NAFLD mice. Through pharmacological inhibition and genetic depletion of P2Y12 as well as in vivo transfusion of wild-type (WT) or CD40L-/- platelets, we demonstrate that the anti-tumor function of platelets is mediated through P2Y12-dependent CD40L release, which leads to CD8+ T cell activation by the CD40 receptor. Unlike P2Y12 inhibition, blocking platelets with aspirin does not prevent platelet CD40L release nor accelerate HCC in NAFLD mice. Similar findings were observed in liver metastasis models. All together, our study reveals a complex role of platelets in tumor regulation. Anti-platelet treatment without inhibiting CD40L release could be considered for liver cancer patients with NAFLD.

Utility of mean platelet volume in differentiating intrahepatic cholangiocarcinoma from hepatocellular carcinoma

Background

Intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC) are the most prevalent histologic types of primary liver cancer. HCC and ICC differ in treatment and prognosis, warranting an effective differential diagnosis between them. This study aimed to explore the clinical value of mean platelet volume (MPV) to discriminate between HCC and ICC.

Material/methods

We performed a retrospective analysis of ICC and HCC patients who were from the Harbin Medical University Cancer Hospital, China. Logistic regression analysis was used to identify the independent factors for the differentiation of HCC and ICC. A receiver operating characteristic curve was built to evaluate the diagnostic performance of the potential model. An independent validation study was performed to validate the diagnostic ability.

Results

ICC patients were detected in 146 out of 348 patients in the primary cohort. MPV levels were decreased in ICC patients compared with those in HCC patients. Logistic regression analysis revealed that MPV was an independent factor in distinguishing HCC from ICC. A combination of sex, hepatitis B surface antigen, MPV, alpha-fetoprotein, and carbohydrate antigen 19–9 demonstrated a good capability to differentiate HCC from ICC. Similar results were achieved in the validation cohort.

Conclusions

MPV may be a new marker to help distinguish ICC from HCC. Further validation studies are required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02348-0.

Joint effect of multiple prothrombotic genotypes and mean platelet volume on the risk of incident venous thromboembolism

BACKGROUND

A high mean platelet volume (MPV), a marker of increased platelet reactivity, is a risk factor for venous thromboembolism (VTE). Whether established prothrombotic single nucleotide polymorphisms (SNPs) further increase the VTE risk in subjects with high MPV because of biological interaction remains unknown.

AIM

To investigate the joint effect of high MPV and prothrombotic genotypes, comprising a 5-SNP genetic risk score (GRS), on the risk of VTE in a population-based case-cohort.

METHODS

Incident VTE cases (n=653) and a subcohort (n=1774) were derived from the Tromsø Study (1994-2012). DNA was genotyped for rs8176719 (ABO), rs6025 (F5), rs1799963 (F2), rs2036914 (F11) and rs2066865 (FGG). Hazard ratios (HRs) for VTE with 95% confidence intervals (CIs) were estimated according to predefined MPV-strata (<8.5, 8.5-9.5, ≥9.5fL) and number of risk alleles for each individual SNP and the GRS (0-1, 2-3, ≥4 risk alleles) in models adjusted for age, sex, body mass index and platelet count.

RESULTS

The combination of high MPV and risk alleles, either as individual SNPs or the GRS, had an additive effect on VTE risk. Compared with subjects with MPV <8.5fL and 0-1 risk allele, those with high MPV (≥9.5fL) and ≥4 risk alleles had HRs of 2.80 (95%CI 1.77-4.43) for overall VTE and 4.60 (95%CI 2.20-9.60) for unprovoked events, respectively, but there was no supra-additive effect on risk estimates.

CONCLUSION

The combination of high MPV and prothrombotic genotypes had an additive effect on VTE risk, suggesting there is no biological interaction between these risk factors in the pathogenesis of VTE.

GPVI expression is linked to platelet size, age, and reactivity

Juvenile platelets show increased GPVI expression.

These platelets are highly responsive and more abundant among large platelets.

Platelets within one individual display heterogeneity in reactivity, size, age, and expression of surface receptors. To investigate the combined intraindividual contribution of platelet size, platelet age, and receptor expression levels on the reactivity of platelets, we studied fractions of large and small platelets from healthy donors separated by using differential centrifugation. Size-separated platelet fractions were perfused over a collagen-coated surface to assess thrombus formation. Multicolor flow cytometry was used to characterize resting and stimulated platelet subpopulations, and platelet age was determined based on RNA and HLA-I labeling. Signal transduction was analyzed by measuring consecutive phosphorylation of serine/threonine-protein kinase Akt. Compared with small platelets, large platelets adhered faster to collagen under flow and formed larger thrombi. Among the large platelets, a highly reactive juvenile platelet subpopulation was identified with high glycoprotein VI (GPVI) expression. Elevated GPVI expression correlated with high HLA-I expression, RNA content, and increased platelet reactivity. There was a stronger difference in Akt phosphorylation and activation upon collagen stimulation between juvenile and older platelets than between large and small platelets. GPVI expression and platelet reactivity decreased throughout platelet storage at 22°C and was better maintained throughout cold storage at 4°C. We further detected higher GPVI expression in platelets of patients with immune thrombocytopenia. Our findings show that high GPVI expression is a feature of highly reactive juvenile platelets, which are predominantly found among the large platelet population, explaining the better performance of large platelets during thrombus formation. These data are important for studies of thrombus formation, platelet storage, and immune thrombocytopenia.

Intratumoral Platelets: Harmful or Incidental Bystanders of the Tumor Microenvironment?

Simple Summary

The tumor microenvironment (TME) is the complex and heterogenous ecosystem of solid tumors known to influence their growth and their progression. Besides tumor cells, the TME comprises a variety of host-derived cell types, ranging from endothelial cells to fibroblasts and immune cells. Clinical and experimental data are converging to indicate that platelets, originally known for their fundamental hemostatic function, also participate in tumor development and shaping of the TME. Considering the abundance of antiplatelet drugs, understanding if and how platelets contribute to the TME may lead to new therapeutic tools for improved cancer prevention and treatments.

Abstract

The tumor microenvironment (TME) has gained considerable interest because of its decisive impact on cancer progression, response to treatment, and disease recurrence. The TME can favor the proliferation, dissemination, and immune evasion of cancer cells. Likewise, there is accumulating evidence that intratumoral platelets could favor the development and aggressiveness of solid tumors, notably by influencing tumor cell phenotype and shaping the vascular and immune TME components. Yet, in contrast to other tumor-associated cell types like macrophages and fibroblasts, platelets are still often overlooked as components of the TME. This might be due, in part, to a deficit in investigating and reporting the presence of platelets in the TME and its relationships with cancer characteristics. This review summarizes available evidence from clinical and animal studies supporting the notion that tumor-associated platelets are not incidental bystanders but instead integral and active components of the TME. A particular emphasis is given to the description of intratumoral platelets, as well as to the functional consequences and possible mechanisms of intratumoral platelet accumulation.

Enrichment of complement, immunoglobulins and autoantibody targets in the proteome of platelets from patients with Systemic Lupus Erythematosus (SLE)

Background  Systemic lupus erythematosus (SLE) is a complex disease characterized by autoimmunity toward apoptotic cells, excessive amounts of circulating immune complexes, and complement activation. A decreased platelet size has been observed in SLE and their nonhemostatic functions may play an active role in the disease. The main objective of this study was to find clues that could explain their decreased size and functional role, analyzing the entire platelet proteome.

Methods  Platelets were isolated from 23 patients with SLE. The five individuals with the highest and lowest average platelet forward scatter were selected for further analysis. Platelet protein content was analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and compared with platelets from five healthy controls. Data are available via ProteomeXchange with identifier PXD031202.

Results  Out of 2,572 proteins identified, 396 had significantly different levels (ANOVA q -value ≤ 0.01). Forty proteins, including immunoglobulin-, complement- and phosphatidylserine-binding proteins had higher abundance in platelets from SLE patients, largely independent of size (fold difference of ≥1.5 and a t -test p -value of ≤0.05 as cut-off). Functional characterization revealed increased degranulation and skewed hemostatic balance in platelets from SLE patients. In the SLE proteome, immunoglobulin proteins were negatively correlated to serum complement C3 and C4 and the highest relative levels were detected in platelets of normal size.

Conclusion  Platelets from SLE patients shared a specific protein profile, including immunoglobulins, complement proteins, and autoantigens, largely independent of the platelet size and in agreement with an integrated role for platelets in SLE.

Association between COVID-19 Diagnosis and Coronary Artery Thrombosis: A Narrative Review

Coronavirus disease 2019 is characterized by its severe respiratory effects. Data early on indicated an increased risk of mortality in patients with cardiovascular comorbidities. Early reports highlighted the multisystem inflammatory syndrome, cytokine storm, and thromboembolic events as part of the disease processes. The aim of this review is to assess the association between COVID-19 and its thrombotic complications, specifically related to the cardiovascular system. The role of neutrophil extracellular traps (NETs) is explored in the pathogenesis of the disease. The structure and anatomy of the virus are pivotal to its virulence in comparison to other α and β Coronaviridae (HCoV-229E, HCoV-OC43, HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1). In particular, the host interaction and response may explain the variability of severity in patients. Angio tensin-converting enzyme 2 (ACE2) activation may be implicated in the cardiovascular and throm bogenic potential of the disease. The virus may also have direct effects on the endothelial lining affecting hemostasis and resulting in thrombosis through several mechanisms. Dipyridamole may have a therapeutic benefit in NET suppression. Therapeutic avenues should be concentrated on the different pathophysiological steps involving the virus and the host.

Mechanisms Underlying Dichotomous Procoagulant COAT Platelet Generation-A Conceptual Review Summarizing Current Knowledge

Procoagulant platelets are a subtype of activated platelets that sustains thrombin generation in order to consolidate the clot and stop bleeding. This aspect of platelet activation is gaining more and more recognition and interest. In fact, next to aggregating platelets, procoagulant platelets are key regulators of thrombus formation. Imbalance of both subpopulations can lead to undesired thrombotic or bleeding events. COAT platelets derive from a common pro-aggregatory phenotype in cells capable of accumulating enough cytosolic calcium to trigger specific pathways that mediate the loss of their aggregating properties and the development of new adhesive and procoagulant characteristics. Complex cascades of signaling events are involved and this may explain why an inter-individual variability exists in procoagulant potential. Nowadays, we know the key agonists and mediators underlying the generation of a procoagulant platelet response. However, we still lack insight into the actual mechanisms controlling this dichotomous pattern (i.e., procoagulant versus aggregating phenotype). In this review, we describe the phenotypic characteristics of procoagulant COAT platelets, we detail the current knowledge on the mechanisms of the procoagulant response, and discuss possible drivers of this dichotomous diversification, in particular addressing the impact of the platelet environment during in vivo thrombus formation.

Low Mean Platelet Volume is Associated with Deep Vein Thrombosis in Older Patients with Hip Fracture

This study aimed to explore the association between mean platelet volume (MPV) and preoperative deep vein thrombosis (DVT) in older patients with hip fracture. A total of 352 consecutive older patients with hip fracture were included from January 2014 to December 2020. MPV values were measured on admission, and color Doppler ultrasonography was performed for DVT screening before the planned surgery. The receiver operating characteristic (ROC) curve was used to establish the optimal cut-off value for the prediction of DVT. Univariate and multivariate logistic regression analysis were used to examine the association between factors and DVT. The overall prevalence of preoperative DVT was 15.1%, and patients with DVT had a lower value of MPV than non-DVT patients (11.6 ± 1.2 fL vs 12.3 ± 1.4 fL, P < .01). The cut-off point according to the ROC curve for MPV was 13.3 fL, and multivariate logistic regression analysis showed that MPV level < 13.3 fL was significantly associated with an increased risk of DVT (OR = 4.857, 95% CI: 1.091-21.617, P = .038), and with every 1.0 fL decrease in MPV, the risk increased by 27.7% (OR = 1.277, 95% CI: 1.001-1.629, P = .047). Our findings indicate that a low MPV level is associated with DVT in older patients with hip fracture. As MPV is a simple indicator that can be calculated from the blood routine test, it may be a potential biomarker of DVT with the combination of other tests, further studies are needed to confirm these results.

The Impact of SARS-CoV-2 Infection on Blood Coagulation and Fibrinolytic Pathways: A Review of Prothrombotic Changes Caused by COVID-19

The cardinal pathology of coronavirus disease 2019 (COVID-19) is a primary infection of pulmonary tract cells by severe acute respiratory syndrome coronavirus 2, provoking a local inflammatory response, often accompanied by cytokine storm and acute respiratory distress syndrome, especially in patients with severe disease. Systemic propagation of the disease may associate with thrombotic events, including deep vein thrombosis, pulmonary embolism, and thrombotic microangiopathy, which are important causes of morbidity and mortality in patients with COVID-19. This narrative review describes current knowledge of the pathophysiological mechanisms of COVID-19-associated coagulopathy, with focus on prothrombotic changes in hemostatic mediators, including plasma levels of clotting factors, natural anticoagulants, components of fibrinolytic system, and platelets. It will also highlight the central role of endothelial cells in COVID-19-associated coagulopathy. This narrative review discusses also potential therapeutic strategies for managing thrombotic complications. Awareness by medical experts of contributors to the pathogenesis of thrombotic events in COVID-19 is imperative to develop therapeutics not limited to regular anticoagulants. Instituting cooperation among medical personnel and researchers may lessen this novel virus' impact now, and in the event of recurrence.

Mean Platelet Volume is Associated with Pancreatic β-Cell Dysfunction in Nondiabetic Patients with Coronary Artery Disease

Purpose

Mean platelet volume (MPV) is an indicator of platelet activation. Pancreatic β-cell dysfunction is one of the fundamental defects contributing to the development of type 2 diabetes. The aim of this study was to assess the relationship between β-cell dysfunction and MPV in nondiabetic patients with coronary artery disease (CAD).

Patients and Methods

A total of 1143 consecutive nondiabetic patients (874 males and 269 females; mean age 60.0±10.3 years) with CAD were recruited for this analysis. All patients were individuals who underwent coronary angiography with a suspicion of CAD. Homeostatic model assessment 2 (HOMA2) of β-cell function (HOMA2-β%) was performed, and β-cell dysfunction was defined by a HOMA2-β% in the lowest quartile.

Results

MPV was significantly higher in CAD patients with β-cell dysfunction than in controls [(10.6±1.0)fl vs (10.0±1.0)fl, P=0.011]. According to the multiple regression model, pancreatic β-cell dysfunction was independently associated with MPV (β=0.210, P=0.006) and age (β=0.008, P=0.028).

Conclusion

MPV was significantly elevated in nondiabetic CAD patients with β-cell dysfunction compared to patients with normal β-cell function.

Autologous Biological Vitamin-C-added (ABC) Filler for Facial Volume Restoration

PURPOSE

Face rejuvenation procedures with injectable agents continue to gain popularity. Nowadays, a variety of commercial products are available as filler material. Ideal fillers should be inexpensive, easily obtainable, nontoxic, and biocompatible. The aim of this study is to report a clinical perspective for an appropriate, feasible, and inexpensive protocol of a stable, autologous biological filler for facial volume restoring without any commercial kits.

METHODS

Eight patients were investigated who underwent facial injection with ABC filler. Eleven ml of whole blood was placed in standard tubes containing anticoagulant and for each patient, 8 tubes were prepared. After the centrifugation at 1630 xg for 5 minutes, the upper plasma was taken, calcium was added and cooled. After the addition of vitamin C, the syringes were incubated at 85 °C for 10 minutes. The autologous biological material obtained was used as filling material. For comparison, FACE-Q satisfaction questionnaires were used before and after the procedure.

RESULTS

All patients were followed up for a minimum of 4 months. No major complications were recorded. The patient-reported FACE-Q satisfaction and FACE-Q quality of life pre- and post-procedure results showed statistically significant improvement (p  <  0.05). Overall satisfaction with the outcome was 89.12 ± 16.73 (range 55-100).

CONCLUSIONS

ABC filler can be seen as a reliable, inexpensive, and easily obtainable material to restore facial volume with increased patient satisfaction and quality of life scores. We believe that our study will be encouraging to the application of autologous biological fillers for further clinical and scientific studies.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Blood Cell Count Indexes of Systemic Inflammation in Carotid Artery Disease: Current Evidence and Future Perspectives

Carotid artery disease is commonly encountered in clinical practice and accounts for approximately 30% of ischemic strokes in the general population. Numerous biomarkers have been investigated as predictors of the onset and progression of carotid disease, the occurrence of cerebrovascular complications, and overall prognosis. Among them, blood cell count (BCC) indexes of systemic inflammation might be particularly useful, from a pathophysiological and clinical point of view, given the inflammatory nature of the atherosclerotic process. The aim of this review is to discuss the available evidence regarding the role of common BCC indexes, such as the neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR), platelet to lymphocyte ratio (PLR), mean platelet volume (MPV), platelet distribution width (PDW), and red cell distribution width (RDW), in the diagnosis and risk stratification of carotid artery disease, and their potential clinical applications.

The SARS-CoV-2/Receptor Axis in Heart and Blood Vessels: A Crisp Update on COVID-19 Disease with Cardiovascular Complications

The SARS-CoV-2 virus causing COVID-19 disease has emerged expeditiously in the world and has been declared pandemic since March 2020, by World Health Organization (WHO). The destructive effects of SARS-CoV-2 infection are increased among the patients with pre-existing chronic conditions and, in particular, this review focuses on patients with underlying cardiovascular complications. The expression pattern and potential functions of SARS-CoV-2 binding receptors and the attributes of SARS-CoV-2 virus tropism in a physio-pathological state of heart and blood vessel are precisely described. Of note, the atheroprotective role of ACE2 receptors is reviewed. A detailed description of the possible detrimental role of SARS-CoV-2 infection in terms of vascular leakage, including endothelial glycocalyx dysfunction and bradykinin 1 receptor stimulation is concisely stated. Furthermore, the potential molecular mechanisms underlying SARS-CoV-2 induced clot formation in association with host defense components, including activation of FXIIa, complements and platelets, endothelial dysfunction, immune cell responses with cytokine-mediated action are well elaborated. Moreover, a brief clinical update on patient with COVID-19 disease with underlying cardiovascular complications and those who had new onset of cardiovascular complications post-COVID-19 disease was also discussed. Taken together, this review provides an overview of the mechanistic aspects of SARS-CoV-2 induced devastating effects, in vital organs such as the heart and vessels.

Combined effects of plasma von Willebrand factor and platelet measures on the risk of incident venous thromboembolism

Plasma von Willebrand factor (VWF) and platelet reactivity are both risk factors for venous thromboembolism (VTE), and VWF can promote hemostasis by interaction with platelets. In this study, we explored the combined effects of plasma VWF and platelet measures on the risk of incident VTE. A population-based nested case-control study with 403 cases and 816 controls was derived from the Tromsø Study. VWF, platelet count and mean platelet volume (MPV) were measured in blood samples drawn at baseline. Odds ratios (ORs) with 95% confidence intervals (CIs) for VTE were estimated across VWF tertiles, within predefined MPV (<8.5, 8.5-9.5, ≥9.5 fL) and platelet count (<230, 230-299, ≥300·109 L-1) strata. Here, participants with VWF levels in the highest tertile and MPV ≥9.5 fL had an OR of 1.98 (95% CI 1.17-3.36) for VTE compared with those in the lowest VWF tertile and with MPV <8.5 fL in the age- and sex-adjusted model. In the joint exposure group, 48% (95% CI 15% to 96%) of VTEs were attributable to the biological interaction between VWF and MPV. Similarly, individuals with VWF in the highest tertile and platelet count ≥300·109 L-1 had an OR of 2.91 (95% CI 1.49-5.67) compared with those with VWF in the lowest tertile and platelet count <230, and 39% (95% CI -2% to 97%) of VTEs in the joint exposure group were explained by the interaction. Our results suggest that both platelet reactivity and platelet count interact biologically with high plasma VWF, resulting in an increased risk of incident VTE.

Platelet reticulated forms, size indexes, and functional activity. Interactions in healthy volunteers

Reticulated platelets (RP) are young, functionally active platelet forms which are detected by RNA staining. Their content in the circulation reflects the intensity of bone marrow thrombocytopoesis. The aim of this study was to assess in healthy volunteers the relationship between RP percentage and platelet size and activity. RP were quantitated by thiazole orange staining using flow cytometry. Platelet size indexes included mean platelet volume (MPV), platelet large cell ratio (P-LCR) measured in a Coulter type hematological analyzer and forward scattering (FSC) measured in a flow cytometer. Platelet functional activity was evaluated by expression of activated glycoprotein (GP) IIb-IIIa (PAC-1 antibody binding) and P-selectin with the use of flow cytometry. Platelets were activated by thrombin receptor activating peptide (TRAP) (10 and 1 µM) and ADP (20 and 2.5 µM). The percentage of RP in healthy volunteers varied from 2.9% to 23.8% (mean ± SD ‒ 11.7 ± 4.7%, n = 99) and correlated with all platelet size indexes: MPV, P-LCR and FCS (r from 0.452 to 0.529, p < .001, n = 87-99). On average, RP were distributed at a ratio of 9:1 between 50% subpopulations of large and small platelets according to their FSC index. Expression of GP IIb-IIIa activated form correlated with RP percentage and platelet size indexes when platelets were activated by TRAP and ADP at both applied concentrations (r from 0.309 to 0.560, p from 0.014 to < 0.001, n = 50-62). P-selectin expression correlated with RP percentage and platelet size indexes when platelets were activated by 10 µM TRAP inducing maximum expression of this activation marker (r from 0.332 to 0.556, p from 0.008 to < 0.001, n = 65), but not by weaker agonists: 1 µM TRAP, 20 and 2.5 µM ADP (r < 0.3, n = 54-66). Thus, high RP content in healthy volunteers is associated with increased platelet size and activity in the whole platelet population.

Reticulated Platelets-Which Functions Have Been Established by In Vivo and In Vitro Data?

Reticulated platelets (RP) are the youngest platelet fraction released into the circulation. These immature platelets have increased RNA content, a larger cell volume, more dense granules, higher levels of surface activation markers and are thought to be more reactive compared to their mature counterparts. RP have been associated with cardiovascular disease, diabetes and increased mortality. Yet only a few animal studies investigating RP have been conducted so far and further investigations are warranted. Established methods to count RP are flow cytometry (staining with thiazole orange or SYTO13) or fully automated hematology analyzers (immature platelet fraction, IPF). IPF has been established as a diagnostic parameter in thrombocytopenia, cardiovascular disease and, in particular, the response to antiplatelet therapy. This review seeks to provide an overview of the key features of RP as well as preanalytical and analytical aspects that need to be considered when working with this platelet population.

Low Intra-Individual Variation in Mean Platelet Volume Over Time in Systemic Lupus Erythematosus

Platelets have recently emerged as important immune modulators in systemic lupus erythematosus (SLE), in addition to their role in thrombosis and cardiovascular disease. However, studies investigating mean platelet volume (MPV) in SLE are often scarce, conflicting and cross-sectional. In this study, MPV was measured in clinical routine throughout a defined time-period to quantify both individual MPV fluctuations and investigate if such variations are associated with disease activity and clinical phenotypes of SLE. Of our 212 patients, 34 patients had only one MPV value reported with the remaining 178 patients having between 2 and 19 visits with recorded MPV values. The intra-individual MPV variation was low, with a median variation of 0.7 fL. This was further supported by the finding that 84% of patients stayed within their reference interval category (i.e., small, normal or large) over time. In our cohort, no correlation between disease activity and MPV neither cross-sectionally nor longitudinally was found. Mean platelet volume values were significantly smaller in SLE patients (mean 10.5 fL) compared to controls (mean 10.8 fL), p < 0.0001. Based on the reference interval, 2.4% (n = 5) of patients had large-sized platelets, 84.4% (n = 179) had normal-sized and 13.2% (n = 28) had small-sized. A larger proportion (85.7%) of patients with small-sized platelets met the anti-dsDNA criterion (ACR10b; p = 0.003) compared to patients with normal and large (57.6%) sized platelets. In conclusion, the intra-individual MPV variation was of low magnitude and fluctuations in disease activity did not have any significant impact on MPV longitudinally. This lack of variability in MPV over time indicates that measuring MPV at any time-point is sufficient. Further studies are warranted to evaluate MPV as a possible biomarker in SLE, as well as to determine the underlying mechanisms influencing platelet size in SLE.

COVID-19 induces a hyperactive phenotype in circulating platelets

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected over 30 million globally to date. Although high rates of venous thromboembolism and evidence of COVID-19-induced endothelial dysfunction have been reported, the precise aetiology of the increased thrombotic risk associated with COVID-19 infection remains to be fully elucidated. Therefore, we assessed clinical platelet parameters and circulating platelet activity in patients with severe and nonsevere COVID-19. An assessment of clinical blood parameters in patients with severe COVID-19 disease (requiring intensive care), patients with nonsevere disease (not requiring intensive care), general medical in-patients without COVID-19, and healthy donors was undertaken. Platelet function and activity were also assessed by secretion and specific marker analysis. We demonstrated that routine clinical blood parameters including increased mean platelet volume (MPV) and decreased platelet:neutrophil ratio are associated with disease severity in COVID-19 upon hospitalisation and intensive care unit (ICU) admission. Strikingly, agonist-induced ADP release was 30- to 90-fold higher in COVID-19 patients compared with hospitalised controls and circulating levels of platelet factor 4 (PF4), soluble P-selectin (sP-selectin), and thrombopoietin (TPO) were also significantly elevated in COVID-19. This study shows that distinct differences exist in routine full blood count and other clinical laboratory parameters between patients with severe and nonsevere COVID-19. Moreover, we have determined all COVID-19 patients possess hyperactive circulating platelets. These data suggest abnormal platelet reactivity may contribute to hypercoagulability in COVID-19 and confirms the role that platelets/clotting has in determining the severity of the disease and the complexity of the recovery path.

The Pathobiological Basis for Thrombotic Complications in COVID-19: a Review of the Literature

Purpose of Review

COVID-19 has rapidly evolved into a global pandemic infecting over two hundred and forty-four million individuals to date. In addition to the respiratory sequelae and systemic infection that ensues, an alarming number of micro and macrovascular thrombotic complications have been observed. This review examines the current understanding of COVID-19-associated thrombotic complications, potential mechanisms, and pathobiological basis for thromboses development.

Recent Findings

The endothelium plays a major role in the process due to direct and indirect injury. The immune system also contributes to a pro-thrombotic environment with immune cell dysregulation leading to excessive formation of cytokines, also called cytokine storm, and an eventual promotion of a hypercoagulable environment, known as immunothrombosis. Additionally, neutrophils play an important role by forming neutrophil extracellular traps, which are shown to be pro-thrombotic and further enhanced in COVID-19 patients. A disruption of the fibrinolysis system has also been observed.

Summary

Multiple pathways likely contribute synergistically to form a pro-thrombotic milieu. A better understanding of these factors and the complex interplay between them will lead to the improvement of diagnostic and therapeutic interventions.

Immature Platelets and Risk of Cardiovascular Events among Patients with Ischemic Heart Disease: A Systematic Review

BACKGROUND

 Immature platelets are larger and may be more thrombogenic than mature platelets. This systematic review included studies on the association between mean platelet volume (MPV), immature platelet count (IPC), and immature platelet fraction (IPF) and the risk of major cardiovascular events (MACEs) in patients with acute coronary syndrome (ACS) or stable coronary artery disease (CAD).

METHODS

 The literature search included studies in PubMed, Embase, Web of Science, and Cochrane Library. The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Effect estimates that included multivariate adjusted odds ratios, relative risks, or hazard ratios were extracted.

RESULTS

 Forty-two studies were identified. High MPV was positively associated with MACE in 20 of 26 studies of patients with ACS, four of five studies in patients with stable CAD, and in all six studies comprising a combined population with ACS and stable CAD. Using continuous models of MPV in patients with ACS, effect estimates varied from 0.90 (95% confidence interval [CI]: 0.95-1.03) to 1.66 (95% CI: 1.32-2.09). The strength of these associations was broadly similar among patients with stable CAD and in combined populations. Five studies investigated IPC or IPF as exposures and all reported positive associations with MACE among patients with ACS, stable CAD, or in combined populations.

CONCLUSION

 This review demonstrated clear evidence for positive associations between measures of immature platelets and subsequent risk of MACE in acute and stable ischemic heart disease patients.

Comparison of the Prognostic Value of Platelet-Related Indices in Biliary Tract Cancer Undergoing Surgical Resection

Purpose

Platelet-related indices, including mean platelet volume (MPV) and plateletocrit (PCT), have been reported as new prognostic factors of overall survival (OS) in many cancers, but not yet in biliary tract cancer (BTC). We intended to assess these indices in predicting OS in BTC patients with the aim to build a new prognostic model for patients with BTC after surgical resection.

Materials and Methods

Survival analysis and time receiver operating characteristic analysis were applied to screen the platelet indices. Univariate and multivariate Cox analyses were used to identify independent prognostic factors and develop a new prognostic model. Harrell’s C-statistics, calibration curves, and decisive curve analysis were used to assess the model.

Results

MPV and platelet distribution width (PDW)/PCT showed the best prognostic accuracy among the platelet indices. In multivariable analysis, factors predictive of poor OS were presence of nodal involvement, Non-radical surgery, poor tumor differentiation, carbohydrate antigen 19-9 > 100 U/mL, MPV > 8.1 fl, and PDW/PCT > 190. The new model was found to be superior to the TNM staging system and our new staging system showed higher discriminative power.

Conclusion

MPV and PDW/PCT have high prognostic value in BTC patients, and the novel staging system based on these two indices showed good discrimination and accuracy compared with the American Joint Committee on Cancer 7th TNM staging system.