Von Willebrand Factor Concentration Research Articles

Clusterin knockdown has effects on intracellular and secreted von Willebrand factor in human umbilical vein endothelial cells.

Alterations in von Willebrand factor (VWF) have an important role in human health and disease. Deficiency of VWF is associated with symptoms of bleeding and excesses of VWF are associated with thrombotic outcomes. Understanding the mechanisms that drive VWF regulation can lead to a better understanding of modulation of VWF levels in humans. We identified clusterin (CLU) as a potential candidate regulator of VWF based on a single cell RNA sequencing (scRNA-seq) analysis in control endothelial cells (ECs) and von Willebrand disease (VWD) endothelial colony-forming-cells (ECFCs). We found that patients with deficiencies of VWF (von Willebrand disease, VWD) had decreased CLU expression and ECs with low VWF expression also had low CLU expression. Based on these findings, we sought to evaluate the role of CLU in the regulation of VWF, specifically as it relates to VWD. As CLU is primarily thought to be a golgi protein involved in protein chaperoning, we hypothesized that knockdown of CLU would lead to decreases in VWF and alterations in Weibel-Palade bodies (WPBs). We used both siRNA- and CRISPR-Cas9-based approaches to modulate CLU in human umbilical vein endothelial cells (HUVECs) and evaluated VWF protein levels, VWF mRNA copy number, and WPB quantity and size. We demonstrated that siRNA-based knockdown of CLU resulted in decreases in VWF content in cellular lysates and supernatants, but no significant change in WPB quantity or size. A CRISPR-Cas9-based knockdown of CLU demonstrated similar findings of decreases in intracellular VWF content but no significant change in WPB quantity or size. Our data suggests that CLU knockdown is associated with decreases in cellular VWF content but does not affect VWF mRNA levels or WPB quantity or size.

Key Drivers of Coagulation Factor Use in Von Willebrand Disease During Hospitalization: An Overview of the French BERHLINGO Cohort.

Von Willebrand disease (VWD) is the most common inherited bleeding disorder. However, studies of hospitalisation patterns with replacement treatment are scarce. The aim of this study was to investigate the current therapeutic management of VWD and determine the key drivers of coagulation factor uses in patients during hospitalisation. Hopscotch-WILL was a multi-centric retrospective study conducted over a 48-month period in any patients with VWD. The data were collected from the BERHLINGO Research Database and the French Hospital database. A total of 988 patients were included; 153 patients (15%) were hospitalised during 293 stays requiring treatment with von Willebrand factor (VWF) concentrates-pure or in association with Factor VIII (FVIII). Their median basal concentrations of VWF and FVIII were significantly lower than in untreated patients: VWF antigen < 30 IU/dL, VWF activity < 20 IU/dL and FVIII:C < 40 IU/dL. The median (interquartile range) concentrate consumption was similar between highly purified VWF or VWF combined with FVIII (72 [110] vs 57 [89] IU/kg/stay, p = 0.154). The use of VWF was highly heterogeneous by VWD type; type 3 had a particularly high impact on VWF consumption in non-surgical situations. The main admissions were for ear/nose/throat, hepato-gastroenterology, and trauma/orthopaedic conditions, besides gynaecological-obstetric causes in women. The use of VWF concentrates is mostly influenced by low basal levels of VWF and FVIII, but also by VWD type or the cause for hospitalisation. These results could inform future studies of newly released recombinant VWF.

Effects of Prolonged Tourniquet Application on Coagulation and Fibrinolysis in Rats

Background Pneumatic tourniquets are routinely used in major orthopedic surgeries such as total knee arthroplasty (TKA) to occlude arterial flow, control perioperative bleeding, and facilitate an unimpeded surgical field 1,2,3. Despite its common use, studies have shown prolonged tourniquet application to be associated with up to a 10% symptomatic incidence of thromboembolic events such as deep vein thrombosis and pulmonary embolism, which are major postoperative complications associated with increased morbidity and mortality. Objectives To evaluate hematologic [Von Willebrand factor (VWF), tissue plasminogen factor (TPA) and D-Dimer (DD)] and histopathologic effects of prolonged tourniquet application in Sprague Dawley rats (SD). Methods Male SD rats (n=37) weight ~325 grams were randomized to an experimental group (n=19) and control group (n=18). Under isoflurane anaesthesia, a cable zip-tie emulating a pneumatic tourniquet was applied around the hind-limb of experimental animals, immediately distal to the head of the femur, at a standardized tightness of 38 newtons using a standardized cable tie hand tool for 3-hours. Control animals remained anaesthetized for the same 3-hour period, but without tourniquet intervention. After 3-hours, the tourniquet was carefully removed on experimental animals. Then in all animals, tail vein blood samples were collected, animals were euthanized and tissue samples of distal vessels (femoral and saphenous arteries and veins) and surrounding soft tissues were extracted. All hematologic parameters were measured using respective Asserachrom antigenic kits (Diagnostic Stago), an enzyme immunoassay by ELISA method. Histologic investigation included a modified Carstairs stain for fibrin and platelets as well as routine hematoxylin-eosin (H&amp;E) staining. Results As can be seen in Figure 1, tourniquet application in the hind limb of experimental animals resulted in complete occlusion of arterial flow distal to the device, leading to bruising, muscle stiffness and bleeding into the local tissue, and associated tissue ischemia. The experimental animals exhibited elevated plasma concentration of DD (289.3 ng/mL vs 67.37 ng/mL, p&amp;lt;0.05), VWF (3.4% vs 2.9%, p=0.19) and TPA (11.4 ng/mL vs 1.0 ng/mL, p&amp;lt;0.05) when compared to its control group (Figure 1). The gross and microscopic evaluation revealed varying degrees of vascular congestion and the presence of post-mortem clot formation in the examined samples. No histological evidence of antemortem thrombosis was observed in either group in the microscopic examination of H&amp;E slides. Conclusion Our animal model demonstrates prolonged tourniquet application to be associated with activation of the coagulation and fibrinolysis cascade, but did not demonstrate histological evidence of antemortem thrombosis. Future animal studies are required to compare the prevalence of thrombosis in the post-operative/tourniquet period, which would mimic the temporality of DVT development in a clinical orthopedic setting. Figure 1: Left: hind limb of control animal after 3 anesthetised hours of no tourniquet application. Right: hind limb of experimental animal after 3 anesthetised hours of prolonged tourniquet application. Bleeding into local tissue, and vascular and muscular tissue damage are visible. Bottom: Microscopic examination of hindlimb blood vessel. H&amp;E staining demonstrating (A) artery, (B) vein, and (*) erythrocytes aggregation (20x magnification). There was no evidence of thrombosis.

OC 60.3 Prevention of Hemorrhage after Implantation of Mechanical Circulatory Support with a Purified Von Willebrand Factor Concentrate: Results of the Early Terminated Randomized Controlled PHAM Trial

OC 60.3 Prevention of Hemorrhage after Implantation of Mechanical Circulatory Support with a Purified Von Willebrand Factor Concentrate: Results of the Early Terminated Randomized Controlled PHAM Trial

Sensitive electrochemical detection of von Willebrand factor using an immunosensor comprising 7,7,8,8-tetracyanoquinodimethane and nickel-based metal–organic framework

In this work, we developed an immunosensor for determining von Willebrand factor (VWF) by combining a nickel-based metal–organic framework (NiBTC) with 7,7,8,8-tetracyanoquinodimethane (TCNQ), assembling them on a screen-printed electrode (SPE), and immobilizing VWF antibodies on the surface to obtain Ab/TCNQ-NiBTC/SPE. The capture of VWF antigens caused steric hindrance, which mitigated the electrochemical response. The immunoreaction caused a change in the peak current of Ab/TCNQ-NiBTC/SPE, which was proportional to the logarithm of VWF concentration in the range of 1–200 ng/mL, with limits of detection and quantification of 0.887 ng/mL and 2.958 ng/mL, respectively. The proposed Ab/TCNQ-NiBTC/SPE was used to investigate the release of VWF from H2O2-induced oxidative-injured human umbilical vein endothelial cells. The extent of cell injury and the amount of VWF released increased with an increase in the exposure time to H2O2; however, as the cells died due to excessive injury, the amount of VWF released decreased. The proposed TCNQ-NiBTC-based immunosensor can facilitate the convenient and accurate detection of VWF.

Issues of cytokine regulation in vibration disease and associated conditions

The article presents the data on the state of cytokine regulation and indicators of endothelial damage when exposed to industrial vibration (general or local) and in combination with arterial hypertension. Changes in the levels of pro-inflammatory and anti-inflammatory cytokines are described, and biomarkers of endothelial dysfunction in the combined course of vibration disease and arterial hypertension are investigated. The study of the cytokine profile and biomarkers of damage to the vascular endothelium in this pathology will allow making early diagnosis of vascular disorders and optimizing preventive measures for workers in vibration hazard industries. Purpose of the study. Improving the quality of early diagnosis and prevention of vibration dis ease in an isolated course and its combination with arterial hypertension based on a study of the cytokine profile and biomarkers of endothelial dysfunction in this pathology. Material and research methods. A comprehensive study included 84 patients with vibration disease from the exposure to local and general vibration of the first and second degree, 61 patients with a combined course of vibration disease from the exposure to local and general second degree vibration and arterial hypertension, and 30 participants in the control group not exposed to industrial vibration and healthy according to medical examination. The levels of pro-inflammatory (IL-1β, IL-8, TNF-α) and anti-inflammatory cytokines (IL-4) and the biomark ers of endothelial damage (EDN1, TGF-β1, VEGF-A, PDGF-BB, fibronectin, and von Willebrand factor) were determined by enzyme immunoassay. Results. The response of the immune system to the effects of industrial vibration is characterized by a cytokine imbalance — an increase in the level of pro-inflammatory cytokines (IL-1β, IL-8, TNFα) and a decrease in the level of anti-inflammatory cytokine (IL-4). With a combined course of vibration disease and arterial hypertension, the cytokine imbalance is characterized by an even more significant increase in serum concentration of IL-1β, IL-8, TNFα and a decrease in serum IL-4 concentration. Endothelial dysfunction in vibration disease from the exposure to both local and general vibration in combination with arterial hypertension is characterized by a significant increase in the serum concentration of EDN1, TGF-β1, VEGF-A, PDGF-BB, fibronectin, and von Willebrand factor. Conclusion. The study of the cytokine profile and biomarkers of damage to the vascular endothelium in this pathology will allow making early diagnosis of vascular disorders and optimizing preventive measures for workers in vibration hazard industries.

Increased Levels of Inflammatory and Endothelial Biomarkers in Blood of Long COVID Patients Point to Thrombotic Endothelialitis.

The prevailing hypotheses for the persistent symptoms of Long COVID have been narrowed down to immune dysregulation and autoantibodies, widespread organ damage, viral persistence, and fibrinaloid microclots (entrapping numerous inflammatory molecules) together with platelet hyperactivation. Here we demonstrate significantly increased concentrations of von Willebrand factor (VWF), platelet factor 4 (PF4), serum amyloid A (SAA), α-2 antiplasmin (α-2AP), endothelial-leukocyte adhesion molecule 1 (E-selectin), and platelet endothelial cell adhesion molecule (PECAM-1) in the soluble part of the blood. It was noteworthy that the mean level of α-2 antiplasmin exceeded the upper limit of the laboratory reference range in Long COVID patients, and the other 5 were significantly elevated in Long COVID patients as compared to the controls. This is alarming if we take into consideration that a significant amount of the total burden of these inflammatory molecules has previously been shown to be entrapped inside fibrinolysis-resistant microclots (thus decreasing the apparent level of the soluble molecules). We conclude that presence of microclotting, together with relatively high levels of six biomarkers known to be key drivers of endothelial and clotting pathology, points to thrombotic endothelialitis as a key pathological process in Long COVID.

Editor’s Choice Articles for April

Editor’s Choice Articles for April

Abstract 28: First Pass Outcomes And Associated Clot Characteristics: Secondary Analysis Of The Excellent Registry

Introduction: EXCELLENT (NCT03685578) is a global prospective, multicenter, real-world registry of mechanical thrombectomy for stroke with the EmboTrap device as first line treatment which includes clot collection and analysis. Aim of the study: To report the rates of clinical outcomes and clot characteristics associated with first pass reperfusion in EXCELLENT. Methods: Per pass angiographic outcomes assessed by an independent core lab were available in 984 subjects Analysis of clot from 538 cases was performed by independent central labs blinded to clinical data. 90-day mRS assessment was blinded to subject data. Results: First pass reperfusion of mTICI 2b-3 (63.2%) and 2c-3 (38.3%) was significantly predictive of mRS 0-2 or ≤pre-stroke (p=0.011 and p=0.016) but not all-cause mortality at 90 days (p=0.080 and p=0.123, respectively). Further, mTICI 2c-3 in one pass was associated with a higher rate of mRS 0-2 or ≤pre-stroke vs. mTICI 2c-3 reperfusion in &gt;1 pass, (55.5% and 45.1%, respectively, p=0.013) and a rate of all-cause mortality at 90 days of 14.6% vs. 19.8% (p=0.097). Full patient characteristics and clinical outcomes are shown in Table 1. Notable clot composition findings included: RBC (%, mean±SD): mTICI 2c-3, 1 pass 47.69±22.25, mTICI 2c-3, &gt;1 pass 43.86±19.05, (p=0.088); fibrin: mTICI 2c-3, 1 pass 23.20±13.80, mTICI 2c-3 &gt;1 pass 25.40 ± 13.52 (p=0.131); von Willebrand factor (VWF): mTICI2c-3, 1 pass 16.09±14.62, mTICI 2c-3, &gt;1 pass 19.42±17.15 (p=0.038). Conclusions: First pass reperfusion in the EXCELLENT registry was associated with better clinical outcomes at 90 days. Clots retrieved with first pass reperfusion had higher RBC and lower fibrin and VWF content compared to those who achieved reperfusion at greater than one pass.

Enhancement of the haemostatic effect of platelets in the presence of high normal concentrations of von Willebrand factor for critically ill patients needing platelet transfusion—a protocol for the will-plate randomised controlled trial

Introductionvon Willebrand Factor (vWF) is a key protein mediating platelet adhesion on the surface of damaged endothelia. To the best of our knowledge, no trial exists that investigated the effect of platelet transfusion in combination with the administration of balanced vWF in severe blood loss, despite being widely used in clinical practice. The Basel Will-Plate study will investigate the impact of the timely administration of balanced vWF (1:1 vWF and FVIII) in addition to platelet transfusion on the need for blood and coagulation factor transfusion in patients admitted to the intensive care unit (ICU) who suffer from severe bleeding. The study hypothesis is based on the assumption that adding balanced vWF to platelets will reduce the overall need for transfusion of blood products compared to the transfusion of platelets alone.Methods and analysisThe Will-Plate study is an investigator-initiated, single-centre, double-blinded randomised controlled clinical trial in 120 critically ill patients needing platelet transfusion. The primary outcome measure will be the number of fresh frozen plasma (FFP) and red blood cell (RBC) transfusions according to groups. Secondary outcome measures include the number of platelet concentrates transfused within the first 48 h after treatment of study medication, quantity of blood loss in the first 48 h after treatment with the study medication, length of stay in ICU and hospital, number of revision surgeries for haemorrhage control, ICU mortality, hospital mortality, 30-day mortality and 1-year mortality. Patients will be followed after 30 days and 1 year for activities of daily living and mortality assessment. The sample size was calculated to detect a 50% reduction in the number of blood products subsequently transfused within 2 days in patients with Wilate® compared to placebo.Ethics and disseminationThis study has been approved by the Ethics Committee of Northwestern and Central Switzerland and will be conducted in compliance with the protocol, the current version of the Declaration of Helsinki, the ICH-GCP or ISO EN 14155 (as far as applicable) and all national legal and regulatory requirements. The study results will be presented at international conferences and published in a peer-reviewed journal.Trials registrationClinicalTrials.gov NCT04555785. Protocol version: Clinical Study Protocol Version 2, 01.11.2020. Registered on Sept. 21, 2020.

Фактор фон Виллебранда и ADAMTS13 как предикторы тромбоза у онкогинекологических пациенток на фоне химиотерапии

The incidence of venous thrombosis in patients undergoing chemotherapy is high. Activation of vascular endothelium during chemotherapy is followed by elevated concentrations of von Willebrand factor (vWF), decreased concentrations of ADAMTS13, and increased thrombotic risk. Objective. To study the significance of vWF:Ag and ADAMTS13:Ag concentrations and the ratio of vWF:Ag to ADAMTS13:Ag (VWF:Ag/ADAMTS13:Ag) as risk factors for thrombosis in gynecologic cancer patients undergoing chemotherapy. Patients and methods. The prospective controlled interventional non-randomized trial included 222 patients aged 34 to 72 years who underwent elective surgical treatment (138 patients) and chemotherapy courses (84 patients), and 50 healthy women in the control group. Concentrations of vWF:Ag and ADAMTS13:Ag, as well as markers of hemostatic activation such as thrombin-antithrombin complex (TAT) and D-dimer were determined in the patients’ plasma before therapy (baseline levels), 14 days after surgical treatment, and 14 days after 2 courses of chemotherapy. Results. Concentrations of vWF:Ag were significantly higher and concentrations of ADAMTS13:Ag were significantly lower among cancer patients both before and after surgical treatment and after chemotherapy compared to healthy controls. There was a significant difference in the dynamics of indicators in patients after chemotherapy compared to patients after surgical treatment. Significant changes in the vWF:Ag/ADAMTS13:Ag ratio between the groups of patients after surgical treatment and on the background of chemotherapy were also confirmed. A correlation was found between an increase in vWF:Ag concentrations, vWF:Ag/ADAMTS13:Ag ratio and TAT concentrations, and thus the risk of thrombosis. The study was conducted against the background of using standard thromboprophylaxis regimens in all patients, considering the high risk of thrombosis in all patients included in the study, according to standard thrombosis risk assessment scales. Conclusion. Concentrations of vWF:Ag, ADAMTS13:Ag and the vWF:Ag/ADAMTS13:Ag ratio can be considered as predictors of thrombosis during chemotherapy in gynecologic cancer patients. Key words: von Willebrand factor, ADAMTS13, cancer, chemotherapy

Temporal Changes in Extracellular Vesicle Hemostatic Protein Composition Predict Favourable Left Ventricular Remodeling after Acute Myocardial Infarction.

The subset of plasma extracellular vesicles (EVs) that coprecipitate with low-density lipoprotein (LDL-EVs) carry coagulation and fibrinolysis pathway proteins as cargo. We investigated the association between LDL-EV hemostatic/fibrinolysis protein ratios and post-acute myocardial infarction (post-AMI) left ventricular (LV) remodeling which precedes heart failure. Protein concentrations of von Willebrand factor (VWF), SerpinC1 and plasminogen were determined in LDL-EVs extracted from plasma samples obtained at baseline (within 72 h post-AMI), 1 month and 6 months post-AMI from 198 patients. Patients were categorized as exhibiting adverse (n = 98) or reverse (n = 100) LV remodeling based on changes in LV end-systolic volume (increased or decreased ≥15) over a 6-month period. Multiple level longitudinal data analysis with structural equation (ML-SEM) model was used to assess predictive value for LV remodeling independent of baseline differences. At baseline, protein levels of VWF, SerpinC1 and plasminogen in LDL-EVs did not differ between patients with adverse versus reverse LV remodeling. At 1 month post-AMI, protein levels of VWF and SerpinC1 decreased whilst plasminogen increased in patients with adverse LV remodeling. In contrast, VWF and plasminogen decreased whilst SerpinC1 remained unchanged in patients with reverse LV remodeling. Overall, compared with patients with adverse LV remodeling, higher levels of SerpinC1 and VWF but lower levels of plasminogen resulted in higher ratios of VWF:Plasminogen and SerpinC1:Plasminogen at both 1 month and 6 months post-AMI in patients with reverse LV remodeling. More importantly, ratios VWF:Plasminogen (AUC = 0.674) and SerpinC1:Plasminogen (AUC = 0.712) displayed markedly better prognostic power than NT-proBNP (AUC = 0.384), troponin-I (AUC = 0.467) or troponin-T (AUC = 0.389) (p < 0.001) to predict reverse LV remodeling post-AMI. Temporal changes in the ratios of coagulation to fibrinolysis pathway proteins in LDL-EVs outperform current standard plasma biomarkers in predicting post-AMI reverse LV remodeling. Our findings may provide clinical cues to uncover the cellular mechanisms underpinning post-AMI reverse LV remodeling.

The role of estimation of plasma von Willebrand factor concentration in stroke risk stratification in patients with atrial fibrillation

Introduction. Von Willebrand factor (vWF) is a large plasma glycoprotein that plays a major role in hemostasis. The vWF plasma concentration is not included in modern stoke risk stratification scales in patients with atrial fibrillation (AF).Aim — to evaluate the possibility of usage of vWF plasma concentration in stroke risk stratification in patients with atrial fibrillation.General findings. vWF is an important predictor of stroke development in patients with AF based on the results of the conducted meta-analysis that included 12 studies and 7449 patients with AF. Determining the concentration of vWF in patients with low risk of stroke development or in those patients with a single non-sex CHA2DS2-VASc score risk factor may be useful in deciding whether to prescribe anticoagulant therapy.

Protection of salidroside on endothelial cell barrier in cerebral ischemia-reperfusion model rats

This study aims to observe the therapeutic effect of salidroside on cerebral ischemia-reperfusion(I/R) model rats, and to specifically explore the protection of salidroside on endothelial cell barrier after I/R and the mechanism. In the experiment, SD rats were randomized into sham group, model group, and high-, medium-, and low-dose(10, 5, and 2.5 mg·kg~(-1)) salidroside groups. The suture method was used to induce I/R in rats. The infarct area, neurobehavioral evaluation, and brain water content were used to evaluate the efficacy of salidroside. As for the experiment on the mechanism, high-dose and low-dose salidroside groups were designed. The pathological morphology was observed based on hematoxylin and eosin(HE) staining, and ultrastructure of vascular endothelial cells based on transmission electron microscopy. The content of nitric oxide(NO) in serum, four indexes of blood coagulation, and the content of von Willebrand factor(vWF) in plasma were measured. Western blot(WB) and immunofluorescence(IF) were employed to determine the expression of tight junction proteins(ZO-1, occluding, and claudin-1) and matrix metalloproteinase 9(MMP-9) in the cortex. The results showed that the model group had obvious neurological deficit, obvious infarct in the right brain tissue, and significant increase in water content in brain tissue compared with the sham group. Compared with the model group, high-dose and low-dose salidroside groups showed decrease in neurobehavioral score, and the high-, medium-, and low-dose salidroside groups demonstrated obviously small infarct area and significant decrease in water content in brain tissue. The results of HE staining and transmission electron microscopy showed that rats had necrosis of neurons, damage of original physiological structure of endothelial cells, and disintegration of the tight junction between endothelial cells after I/R compared with the sham group. Compared with the model group, the high-dose and low-dose salidroside groups showed alleviation of neuron injury and intact physiological structure of endothelial cells. The model group had significantly lower serum level of NO, significantly higher plasma levels of vWF and fibrinogen(FIB), and significantly shorter thrombin time(TT) and prothrombin time(PT) than the sham group. Compared with model group, the high-dose and low-dose salidroside groups increased the serum content of NO in serum, decreased the plasma levels of FIB and vWF, and significantly prolonged TT and PT. WB and IF results showed that the model group had significantly lower levels of ZO-1, occluding, and claudin-1 among endothelial cells and significantly higher level of MMP-9 than the sham group. Compared with the model group, high-dose and low-dose salidroside significantly increased the levels of ZO-1, occluding, and claudin-1 in the cortex. The above experimental results show that salidroside has clear therapeutic effect on I/R rats and protects the brain. To be specific, it alleviates the damage of endothelial cells by increasing NO synthesis in endothelial cells, inhibiting coagulation reaction and MMP-9 expression, up-regulating the expression of ZO-1, occludin, and claudin-1, thereby protecting the brain.

Thrombus formation during ECMO: Insights from a detailed histological analysis of thrombus composition

ObjectivesIntra‐device thrombosis remains one of the most common complications during extracorporeal membrane oxygenation (ECMO). Despite anticoagulation, approximately 35% of patients develop thrombi in the membrane oxygenator, pump heads, or tubing. The aim of this study was to describe the molecular and cellular features of ECMO thrombi and to study the main drivers of thrombus formation at different sites in the ECMO circuits. Approach and ResultsThrombi (n = 85) were collected immediately after veno‐arterial‐(VA)‐ECMO circuit removal from 25 patients: 23 thrombi from the pump, 25 from the oxygenator, and 37 from the tubing. Quantitative histological analysis was performed for the amount of red blood cells (RBCs), platelets, fibrin, von Willebrand factor (VWF), leukocytes, and citrullinated histone H3 (H3Cit). ECMO thrombi consist of a heterogenous composition with fibrin and VWF being the major thrombus components. A clustering analysis of the four major histological parameters identified two typical thrombus types: RBC‐rich and RBC‐poor/fibrin‐rich thrombi with no significant differences in VWF and platelet content. Thrombus composition was not associated with the thrombus location, except for higher amounts of H3Cit that were found in pump and oxygenator thrombi compared to tubing samples. We observed higher blood leukocyte count and lactate dehydrogenase levels in patients with fibrin‐rich thrombi. ConclusionWe found that thrombus composition is heterogenous, independent of their location, consisting of two types: RBC‐rich and a fibrin‐rich types. We also found that NETs play a minor role. These findings are important to improve current anticoagulation strategies in ECMO.

Platelets are indispensable for alveolar development in neonatal mice.

Previous studies suggest that platelets are involved in fetal and adult lung development, but their role in postnatal lung development especially after premature birth is elusive. There is an urgent need to scrutinize this topic because the incidence of bronchopulmonary dysplasia (BPD), a chronic lung disease after premature birth, remains high. We have previously shown impaired platelet biogenesis in infants and rats with BPD. In this study, we investigated the role of anti-CD41 antibody-induced platelet depletion during normal postnatal lung development and thrombopoietin (TPO)-induced platelet biogenesis in mice with experimental BPD. We demonstrate that platelet deficient mice develop a BPD-like phenotype, characterized by enlarged alveoli and vascular remodeling of the small pulmonary arteries, resulting in pulmonary arterial hypertension (PAH)-induced right ventricular hypertrophy (RVH). Vascular remodeling was potentially caused by endothelial dysfunction demonstrated by elevated von Willebrand factor (vWF) concentration in plasma and reduced vWF staining in lung tissue with platelet depletion. Furthermore, TPO-induced platelet biogenesis in mice with experimental BPD improved alveolar simplification and ameliorated vascular remodeling. These findings demonstrate that platelets are indispensable for normal postnatal lung development and attenuation of BPD, probably by maintaining endothelial function.

Preparation and Storage of Cryoprecipitate Derived from Amotosalen and UVA-Treated Apheresis Plasma and Assessment of In Vitro Quality Parameters.

Cryoprecipitate is a plasma-derived blood product, enriched for fibrinogen, factor VIII, factor XIII, and von Willebrand factor. Due to infectious risk, the use of cryoprecipitate in Central Europe diminished over the last decades. However, after the introduction of various pathogen-reduction technologies for plasma, cryoprecipitate production in blood centers is a feasible alternative to pharmaceutical fibrinogen concentrate with a high safety profile. In our study, we evaluated the feasibility of the production of twenty-four cryoprecipitate units from pools of two units of apheresis plasma pathogen reduced using amotosalen and ultraviolet light A (UVA) (INTERCEPT® Blood System). The aim was to assess the compliance of the pathogen-reduced cryoprecipitate with the European Directorate for the Quality of Medicines (EDQM) guidelines and the stability of coagulation factors after frozen (≤−25 °C) storage and five-day liquid storage at ambient temperature post-thawing. All pathogen-reduced cryoprecipitate units fulfilled the European requirements for fibrinogen, factor VIII and von Willebrand factor content post-preparation. After five days of liquid storage, content of these factors exceeded the minimum values in the European requirements and the content of other factors was sufficient. Our method of production of cryoprecipitate using pathogen-reduced apheresis plasma in a jumbo bag is feasible and efficient.

Thrombomodulin and von willebrand factor as markers of endothelial dysfunction in patients with chronic kidney disease

The aim of research was to study the levels of thrombomodulin (TM) and von Willebrand factor (VWF) in the serum and urine of patients with chronic kidney disease (CKD)as diagnostic markers of endothelial dysfunction. The study involved 140 patients with CKD. The clinical diagnosis was determined based on standard methods of patients examination according to the kidney diseases classification and protocols of CKD patients management. The concentrations of TM and VWF in serum and urine were quantified by ELISA. A generalized endothelial dysfunction in the vessels of the whole body, including the kidneys and high concentration of TM and FVF in the serum and urine of patients with a diabetic nephropathy have been found. The concentration of TM and VWF in the serum of patients with a chronic glomerulonephritis was at the same level as in the serum of healthy individuals, while those in urine significantly exceeded the control values, indicating endothelial damage in the glomeruli of the kidneys due to exposure to pro-inflammatory cytokines. In our opinion, the studied markers will contribute to the timely diagnosis of endothelial dysfunction in patients with CKD and to the development of criteria for prescribing antiplatelet agents in glomerular kidney disease.

The Role of Vascular-Platelet Hemostasis Disturbances in the Genesis of Respiratory Failure in Patients with COVID-19

The objective: to study the relationship between markers of imbalance in the platelet-vascular hemostasis system and lung damage and disease outcome in patients with COVID-19.Subjects and Methods: the study included 225 patients with the confirmed diagnosis of moderate, severe and extremely severe COVID-19. In all patients, lung damage was confirmed using computed and X-ray diagnostic methods. We studied the concentration of von Willebrand factor (vWF), activity of metalloproteinase ADAMTS-13, concentration of homocysteine, endothelin-1, thrombomodulin and the number of platelets and changes in these parameters on the 1st, 3–5th and 7–10th days from the admission to the intensive care unit (ICU). In deceased patients (n = 106), lung specimens were collected to assess the nature of morphological changes.Results. It was determined that by the 7–10th days with a lethal outcome of the disease, there was a statistically significant increase in the concentration of vWF by 22.2% (p = 0.0225), the vWF/ADAMTS-13 ratio by 2 times (p = 0.0408) and decrease in the platelet count by 52% (p = 0.0008) versus the initial stage of the study. In all the deceased, the morphological picture of lung tissue damage was characterized by destruction of alveolocytes, proliferation of connective tissue, cellular infiltration, plethora of capillaries, parietal erythrocyte thrombi in the lumen of capillaries, arterioles and venules, and obstructive erythrocyte thrombi in the lumen of vessels of lung microcirculation.Conclusion. The study showed that a possible cause of thrombosis in the lumen of vessels of lung microcirculation in the case of a lethal outcome of COVID-19 might be a primary imbalance in the vascular-platelet hemostasis characterized by a significant increase in the concentration of the vWF factor, the vWF/ADAMTS-13 ratio and a decrease in the number (consumption) of platelets by the 7–10th day of the disease versus the initial stage of the study.

This Month in Anesthesiology

This Month in Anesthesiology