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Background: High mechanical shear stress (HMSS) generated by blood pumps during mechanical circulatory support induces blood damage (or function alteration) not only of blood cell components but also of plasma proteins. Methods: In the present study, fresh, healthy human blood was used to prime a blood circuit assisted by a CentriMag centrifugal pump at a flow rate of 4.5 L/min under three pump pressure heads (75, 150, and 350 mm Hg) for 4 h. Blood samples were collected for analyses of plasma‐free hemoglobin (PFH), von Willebrand factor (VWF) degradation and platelet glycoprotein (GP) IIb/IIIa receptor shedding. Results: The extent of all investigated aspects of blood damage increased with increasing cross‐pump pressure and duration. Loss of high‐molecular‐weight multimers (HMWM)‐VWF in Loop 2 and Loop 3 significantly increased after 2 h. PFH, loss of HMWM‐VWF, and platelet GPIIb/IIIa receptor shedding showed a good linear correlation with mean shear stress corresponding to the three pump pressure heads. Conclusions: HMSS could damage red blood cells, cause pathological VWF degradation, and induce platelet activation and platelet receptor shedding. Different blood components can be damaged to different degrees by HMSS; VWF and VWF‐enhanced platelet activation may be more susceptible to HMSS. [ABSTRACT FROM AUTHOR]

Pulmonary fibrosis (PF) can be a fatal disease characterized by progressive lung scarring. It is still poorly understood how the pulmonary endothelium is involved in the disease pathogenesis. Differences of the pulmonary vasculature between patients and donors were analyzed using transmission electron microscopy, immunohistochemistry, and single-cell RNA sequencing. Vascular barrier resistance, endothelial–immune cell adhesion, and sensitivity to an inflammatory milieu were studied in vitro. Integrity and activation markers were measured by ELISA in human plasma. Transmission electron microscopy demonstrated abnormally swollen endothelial cells (ECs) in fibrotic lungs compared with donors. A more intense CD31 and von Willebrand Factor (vWF) and patchy vascular endothelial (VE)-Cadherin staining in fibrotic lungs supported the presence of a dysregulated endothelium. Integrity markers CD31, VE-Cadherin, Thrombomodulin, and VEGFR-2 (vascular endothelial growth factor receptor-2) and activation marker vWF gene expression was increased in different endothelial subpopulations (e.g., arterial, venous, general capillary, aerocytes) in PF. This was associated with a heightened sensitivity of fibrotic ECs to TNF-α or IFN-γ and elevated immune cell adhesion. The barrier strength was overall reduced in ECs from fibrotic lungs. vWF and IL-8 were increased in the plasma of patients, whereas VE-Cadherin, Thrombomodulin, and VEGFR-2 were decreased. VE-Cadherin staining was also patchy in biopsy tissue and was decreased in plasma samples of patients with PF 6 months after the initial diagnosis. Our data demonstrate highly abnormal ECs in PF. The vascular compartment is characterized by hyperactivation and increased immune cell adhesion, as well as dysfunctional endothelial barrier function. Reestablishing EC homeostasis and function might represent a new therapeutic option for fibrotic lung diseases. [ABSTRACT FROM AUTHOR]

Context: IntelliSep by Cytovale has received United States (U.S.) Food and Drug Administration (FDA) approval as a sepsis biomarker test. However, the clinical utility of this new test is not assessed in emergency departments. Objective: We investigated the clinical utility of this test using 44 patients visiting the emergency department at The University of Kansas Medical Center by comparing it with the monocyte distribution width (MDW) and other biomarkers including the von Willebrand factor (vWF) and ADAMTS13. Design and Methods: IntelliSep assesses the cellular host response via deformability cytometry of biophysical leukocyte properties and produces a score (IntelliSep Index; ISI: from 0.1 (lowest risk) to 10 (highest risk). We measured the ISI in 44 patients (19 high probability and 25 low probability of sepsis groups) using EDTA-anticoagulated blood. Left over plasma was used for measuring the plasma von Willebrand factor (vWF) and ADAMTS13 antigen by ELISA assays. The MDW was obtained during routine CBC analysis using a Beckman hematology analyzer. The lactate and high-sensitivity troponin I levels were measured using a Beckman analyzer. Procalcitonin was measured using a Cobas e801 analyzer. Results: The median ISI was twofold higher in the high-probability group than in the low-probability group (p < 0.01) while the median MDW was 34.5% higher in the high-probability group than in the low-probability group (p < 0.01). However, the correlation between the ISI and MDW was only modest (r = 0.66). In addition, significantly higher levels of plasma vWF antigen but lower levels of plasma ADAMTS13 antigen in the high-probability group were found, resulting in significantly higher vWF/ADAMTS13 ratios in the high-probability group than in the low-probability group. Conclusions: The new IntelliSep test along with vWF/ADAMTS13 ratios may be useful for the early diagnosis of sepsis in patients visiting the emergency department, which appears to be superior to the traditional marker, MDW. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to explore the differential effects of varying doses of atorvastatin on antagonizing lipopolysaccharide (LPS)-induced endothelial inflammation based on heme oxygenase 1 (HO-1) expression. Method: Vascular endothelial inflammatory injury was induced in 40 Sprague-Dawley rats by intraperitoneal injection of LPS. These rats were randomly divided into control, low-dose atorvastatin, high-dose atorvastatin, and HO-1 blocking groups. Seven days after treatment, all rats were sacrificed, and heart-derived peripheral blood was collected to measure the serum concentrations of bilirubin, alanine aminotransferase (ALT), total cholesterol, malondialdehyde, endothelial cell protein C receptor, endothelin-1, von Willebrand factor, and soluble thrombomodulin. Meanwhile, the number of circulating endothelial cells was determined using flow cytometry. Vascular tissues from descending aorta of rats from each group were extracted to detect the expression level of HO-1. Results: After different doses of atorvastatin intervention, the above inflammatory indices were decreased, and HO-1 expression and ALT concentration were increased in the atorvastatin-treated group of rats compared with the control group. These changes were more pronounced in the high-dose statin group (P < 0.05). Conversely, no significant decrease in the above inflammatory indices and no significant increase in HO-1 expression were observed in rats in the blocking group (P > 0.05). Conclusion: For LPS-induced vascular inflammation, high-dose atorvastatin exerts potent anti-inflammatory and vascular endothelial protection effects by inducing HO-1 expression. [ABSTRACT FROM AUTHOR]

Background: Juvenile dermatomyositis (JDM) is a systemic vasculopathy associated with metabolic derangements and possible increased risk for premature atherosclerosis. Oxidation of low-density lipoprotein (LDL) in the endothelium is an early step in atherosclerotic plaque formation. It is not known if oxidized LDL is altered in children with untreated JDM. The deposition of oxidized LDL in the vasculature of muscle biopsies (MBx) from patients with untreated JDM and pediatric controls was assessed. Findings: Frozen tissue sections of MRI-directed MBx from 20 female children with untreated JDM and 5 female controls were stained with DAPI and fluorescently labeled antibodies against von Willebrand factor (vWF) and LDL oxidized by copper (oxLDL). Blood vessels were identified by positive vWF staining, and total fluorescence of oxLDL within the vessel walls was measured. Children with untreated JDM had increased deposition of oxLDL in the walls of muscle vasculature compared to healthy children (difference in means ± SEM = 19.86 ± 8.195, p = 0.03). Within the JDM cohort, there was a trend towards increased oxLDL deposition with longer duration of untreated disease (r = 0.43, p = 0.06). There was no significant correlation found between oxLDL deposition and markers of acute JDM disease activity including disease activity scores or muscle enzymes. Conclusions: This study found increased deposition of oxLDL within blood vessels of children with untreated JDM supporting the concern that these children are at increased risk for premature atherosclerosis from chronic exposure to vascular oxLDL. This study highlights the importance of early diagnosis and treatment initiation to ameliorate cardiovascular damage. [ABSTRACT FROM AUTHOR]

Our aim was to explore possible relationships between serum levels of biomarkers in patients with hand-arm vibration injury in relation to the severity of the vascular, i.e., Raynaud's phenomenon (RP), and neurosensory manifestations, the current exposure level, and the duration of exposure. This study was of case series design and involved 92 patients diagnosed with hand-arm vibration injury. Jonckheere's trend test was used to assess any association between serum levels of biomarkers and RP as well as neurosensory manifestations, graded by the International Consensus Criteria. Generalized linear models with adjustment for possible confounders were also used for associations between serum levels of biomarkers and; (1) severity of RP recorded as the extent of finger blanching calculated with Griffin score, (2) vibration perception thresholds, (3) magnitude of current exposure as [A(8); (m/s2)] value, and (4) the duration of exposure in years. Serum levels of thrombomodulin, von Willebrand factor, calcitonin gene related peptide (CGRP), heat shock protein 27, and caspase-3 were positively associated with severity of RP. Serum levels of CGRP were positively associated with the neurosensory component. No associations with exposure were shown for these biomarkers. For Intercellular adhesion molecule 1 and monocyte chemoattractant protein 1, no associations were found with neither severity nor exposure. Levels of serum biomarkers associated with endothelial injury or dysfunction, inflammation, vasodilation, neuroprotection, and apoptosis were positively associated with the severity of hand-arm vibration injury. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion Von Willebrand factor (VWF) is a critical glycoprotein in hemostasis and is an important factor in diagnosing bleeding disorders. Albeit the analysis of VWF is often compromised by inconsistent methodologies and challenges quantifying multimeric size. Current VWF multimer analysis methods are costly, time‐consuming, and often inconsistent; thus, demanding skilled professionals. This study aimed to streamline and optimize the VWF multimer analysis technique, making it more efficient and reproducible, particularly for identifying or predicting mechanical circulatory support (MCS) induced bleeding disorders.Blood samples from healthy volunteers were exposed to high shear forces via a Medtronic HeartWare ventricular assist device. VWF multimers were analyzed using vertical‐gel agarose electrophoresis and Western blotting. Differences in VWF distribution were determined using densitometry, and two methods of densitometric analysis were compared: proprietary software against open‐source software.Using the developed method: (i) protocol duration was accelerated from three days (in classical methods) to ~ eight hours; (ii) the resolution of the high molecular weight (HMW) VWF multimers were substantially improved; and (iii) densitometric analysis tools were validated. Additionally, the densitometry analysis using two software types showed a strong correlation between results, with the proprietary software reporting slightly higher HMW VWF percentages.This methodology is recommended for affordable, accurate, and reproducible VWF multimer evaluations during MCS use and testing. Further research comparing this method with semi‐automated methods would provide additional insight and improve inter‐laboratory comparisons. [ABSTRACT FROM AUTHOR]

Background: Blood group, bleeding time (BT), and clotting time (CT) are routinely performed tests in the hospital, especially before any surgeries and blood transfusion. Aims and Objectives: The objective of the study is to see if there is any association of blood group with BT and CT and the gender difference in BT and CT. Materials and Methods: A cross-sectional study was conducted among 132 medical students of 1st year in the hematology laboratory of the Department of Physiology in KIST Medical College from June 2022 to September 2022. The blood group was determined by a simple agglutination method. BT was determined by Dukes method whereas CT was determined using capillary tube method. Data were analyzed using SPSS-20 software. The difference in BT and CT among various blood groups was done using the ANOVA test and P≤0.05 was considered significant. Student's t-test was used to find the association of gender with BT and CT. Results: Both BT and CT were found to be more in males than females. However, the difference was significant only in the mean BT (P=0.05, Table 2). There was no significant difference in the mean BT among various blood groups but CT was found to be significant (P=0.05). Conclusion: Our study showed the tendency of bleeding to be more in blood Group B individuals. Multicentric study including a larger population with plasma level of von Willebrand factor might be helpful to verify findings and identify the risk group. [ABSTRACT FROM AUTHOR]

Plant height, spike, leaf, stem and grain morphologies are key components of plant architecture and related to wheat yield. A wheat (Triticum aestivum L.) mutant, wpa1, displaying temperature-dependent pleiotropic developmental anomalies, was isolated. The WPA1 gene, encoding a von Willebrand factor type A (vWA) domain protein, was located on chromosome arm 7DS and isolated by map-based cloning. The functionality of WPA1 was validated by multiple independent EMS-induced mutants and gene editing. Phylogenetic analysis revealed that WPA1 is monocotyledon-specific in higher plants. The identification of WPA1 provides opportunity to study the temperature regulated wheat development and grain yield. [ABSTRACT FROM AUTHOR]

Background: Elevated factor XI (FXI) has been shown to predispose to thromboembolism. We investigated whether it is associated with left ventricular thrombus (LVT) formation, its recurrence and subsequent thromboembolic events. Methods: In 54 patients with prior LVT of unknown origin, who stopped anticoagulation and 54 controls, we determined FXI, along with plasma clot permeability (Ks), fibrinolysis time (CLT), endogenous thrombin potential (ETP), von Willebrand factor (vWF) and fibrinolysis proteins. During follow‐up, the primary endpoint involving the recurrence of LVT a symptomatic ischemic stroke or systemic embolism was recorded. Results: Elevated (>120%) FXI levels were more often observed in LVT patients when compared to the control group (14 [25.9%] vs. 6 [11.1%], p =.048) in association with the presence of active FXI. FXI correlated with age (r =.406, p =.002), Ks (r = −.542, p <.001) and CLT (r =.406, p =.002), also after adjustment for age, but not with ETP, vWF or fibrinolysis proteins. During follow‐up of 77.6 ± 18.5 months the primary endpoint occurred in 17 (31.5%) LVT patients, including 11 (20.4%) recurrent LVT, and in 4 (7.4%) controls (annual incidence rate 4.9% vs. 1.1%, respectively; p =.002). On multivariate logistic regression analysis, elevated FXI was independently associated with the primary endpoint (OR 1.18; 95% CI 1.09–1.28). Conclusions: Elevated FXI in association with a prothrombotic state characterizes patients with prior LVT of unknown origin and predisposes to its recurrence and/or ischemic stroke during follow‐up. It might be speculated that the measurement of FXI helps identify patients who could benefit from prolonged anticoagulation and FXI inhibitors in the future. [ABSTRACT FROM AUTHOR]

Primary aldosteronism is a common clinical syndrome in hypertensive patients. Early identification and timely treatment of primary aldosteronism are of great significance to improve the prognosis of patients. Endothelial dysfunction is currently considered an important potential pathological change in primary aldosteronism. In this study, we observed that the levels of von Willebrand factor and soluble intercellular adhesion molecule-1 were significantly elevated in primary aldosteronism and were closely associated with pathological progression. Von Willebrand factor and soluble intercellular adhesion molecule-1 are important adhesion factors in blood, and their levels are directly related to blood viscosity. Meanwhile, both markers showed excellent efficacy in diagnosing primary aldosteronism in hypertensive patients. Additionally, an inverse correlation of soluble intercellular adhesion molecule-1 and primary aldosteronism with the nutritional protein levels of primary aldosteronism patients was identified, which also confirms the promising potential of von Willebrand factor and soluble intercellular adhesion molecule-1 for dynamic nutritional status assessment in primary aldosteronism. These findings are of great significance for the future clinical diagnosis and treatment of primary aldosteronism. [ABSTRACT FROM AUTHOR]

Pif is a shell matrix protein (SMP) identified in the nacreous layer of Pinctada fucata (Pfu) comprised two proteins, Pif97 and Pif 80. Pif97 contains a von Willebrand factor A (VWA) and chitin-binding domains, whereas Pif80 can bind calcium carbonate crystals. The VWA domain is conserved in the SMPs of various mollusk species; however, their phylogenetic relationship remains obscure. Furthermore, although the VWA domain participates in protein–protein interactions, its role in shell formation has not been established. Accordingly, in the current study, we investigate the phylogenetic relationship between PfuPif and other VWA domain-containing proteins in major mollusk species. The shell-related proteins containing VWA domains formed a large clade (the Pif/BMSP family) and were classified into eight subfamilies with unique sequential features, expression patterns, and taxa diversity. Furthermore, a pull-down assay using recombinant proteins containing the VWA domain of PfuPif 97 revealed that the VWA domain interacts with five nacreous layer-related SMPs of P. fucata, including Pif 80 and nacrein. Collectively, these results suggest that the VWA domain is important in the formation of organic complexes and participates in shell mineralisation. [ABSTRACT FROM AUTHOR]

Heyde's syndrome (HS) represents an association between aortic stenosis and intestinal angiodysplasias, and it has been demonstrated that acquired von Willebrand disease plays a pivotal role in the pathophysiology of this syndrome. In patients with HS, von Willebrand factor deficiency represents an additional risk factor, further contributing to the risk of bleeding and anemia. We present the case of an 86-year-old patient diagnosed with HS and von Willebrand deficiency in 2018. Four years prior, the patient underwent surgical aortic valve replacement. Since then, she has been receiving chronic oral anticoagulation therapy with a vitamin K antagonist. The patient was admitted to the Internal Medicine Clinic due to semi-solid dark stools, diffuse abdominal pain, and asthenia. Upon examination, the patient presented with an altered general status and clinical signs suggestive of anemia. Laboratory findings revealed anemia with elevated INR and aPTT values. Colonic angiodysplasias were identified during a colonoscopy, although no sources of active bleeding were detected. On the 9th day of hospitalization, the patient experienced an episode of lower gastrointestinal bleeding. The pharmacological management was adjusted, and argon plasma coagulation was recommended. Following treatment of the angiodysplastic lesions, the patient's clinical evolution was favorable, with the correction of the anemia. [ABSTRACT FROM AUTHOR]

Aortic stenosis (AS) is a prevalent valvular disorder that poses a significant burden on healthcare systems due to its debilitating symptoms and high mortality rates if left untreated. Surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) are the primary interventions for severe AS, but perioperative complications such as bleeding remain a concern. Von Willebrand factor (VWF), a crucial player in hemostasis, is known to be altered in AS and may contribute to the hemostatic imbalance observed in these patients. This prospective study aimed to investigate the association between prosthetic valve type, size, and postprocedural VWF levels in patients undergoing aortic valve replacement (AVR) for severe AS. This study involved 39 consecutive patients diagnosed with severe AS who underwent SAVR or TAVR. By elucidating the VWF dynamics associated with different prosthetic valves, this study sought to provide valuable insights into personalized valve selection and perioperative management strategies. [ABSTRACT FROM AUTHOR]

Non-invasive tests (NITs) for clinically significant portal hypertension (CSPH) require validation in patients with hepatitis D virus (HDV)-related compensated advanced chronic liver disease (cACLD). Therefore, we aimed to validate existing NIT algorithms for CSPH in this context. Patients with HDV-cACLD (LSM ≥10 kPa or histological METAVIR F3/F4 fibrosis) who underwent paired HVPG and NIT assessment at Medical University of Vienna or Hannover Medical School between 2013 and 2023 were retrospectively included. Liver stiffness measurement (LSM), von Willebrand factor to platelet count ratio (VITRO), and spleen stiffness measurement (SSM) were assessed. Individual CSPH risk was calculated according to previously published models (ANTICIPATE, 3P/5P). The diagnostic performance of Baveno VII criteria and refined algorithms (Baveno VII-VITRO, Baveno VII-SSM) was evaluated. The prognostic utility of NITs was investigated in the main cohort and an independent, multicenter, validation cohort. Fifty-one patients (HVPG ≥10 mmHg/CSPH prevalence: 62.7%, varices: 42.2%) were included. Patients with CSPH had significantly higher LSM (25.8 [17.2-31.0] vs. 14.0 [10.5-19.8] kPa; p <0.001), VITRO (n = 31, 3.5 [2.7-4.5] vs. 1.3 [0.6-2.0] %/[G/L]; p <0.001), and SSM (n = 20, 53.8 [41.7-75.5] vs. 24.0 [17.0-33.9] kPa; p <0.001). Composite CSPH risk models yielded excellent AUROCs (ANTICIPATE: 0.885, 3P: 0.903, 5P: 0.912). Baveno VII criteria ruled out CSPH with 100% sensitivity and ruled in CSPH with 84.2% specificity. The Baveno VII 'grey zone' (41.1%) was significantly reduced by Baveno VII-VITRO or Baveno VII-SSM algorithms, which maintained diagnostic accuracy. Hepatic decompensation within 2 years only occurred in patients who had CSPH or met Baveno VII rule-in criteria. The prognostic value of NITs was confirmed in the validation cohort comprising 92 patients. Standalone and composite NIT/diagnostic algorithms are useful for CSPH diagnosis in patients with HDV-cACLD. Thus, NITs may be applied to identify and prioritize patients with CSPH for novel antiviral treatments against chronic hepatitis D. Non-invasive tests (NITs) for clinically significant portal hypertension (CSPH) have been developed to identify patients with compensated advanced chronic liver disease (cACLD) at risk of decompensation, but conflicting data has been published regarding the accuracy of liver stiffness measurement (LSM) for the staging of fibrosis in patients infected with hepatitis D virus (HDV). In our study, including 51 patients with HDV-cACLD, LSM- and lab-based NITs yielded high AUROCs for CSPH. Moreover, only patients with CSPH or high non-invasively assessed CSPH risk were at risk of decompensation within 2 years, with the prognostic value of NITs confirmed in a validation cohort. Thus, NITs should be applied and updated in yearly intervals in clinical routine to identify patients with HDV-cACLD at short-term risk of clinical events; NITs may also guide prioritization for novel antiviral treatment options. [Display omitted] • NITs for CSPH can be applied in HDV-cACLD with high accuracy. • NITs have similar ability to identify high-risk patients with HDV-cACLD as HVPG. • NITs may guide novel antiviral treatment prioritization and individualized prognostication. [ABSTRACT FROM AUTHOR]

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening, often immune-mediated disease that affects 2–13 persons per million per year. Hemolytic anemia, thrombocytopenia, and end-organ damage due to the formation of microthrombi are characteristic of TTP. ADAMTS13 is a disintegrin, metalloproteinase, cleaving protein of von Willebrand factor (VWF) that processes the VWF multimers to prevent them from interacting with platelets and, in turn, to microvascular thrombosis. Prompt diagnosis of TTP is critical yet challenging. Thrombotic microangiopathies have similar clinical presentation. Measurement of ADAMTS13 activity helps in the differential diagnosis. Less than 10% ADAMTS13 activity is indicative of TTP. Laboratory ADAMTS13 activity assays include incubating the test plasma with the substrate (full-length VWM multimers) and detection with direct or indirect measurement of the cleavage product. The purpose of this study is to examine the diagnostic potential, advantages, and weaknesses of the ADAMTS13 potency in TTP. [ABSTRACT FROM AUTHOR]

The blood protein Von Willebrand factor (VWF) is critical in facilitating arterial thrombosis. At pathologically high shear rates, the protein unfolds and binds to the arterial wall, enabling the rapid deposition of platelets from the blood. We present a novel continuum model for VWF dynamics in flow based on a modified viscoelastic fluid model that incorporates a single constitutive relation to describe the propensity of VWF to unfold as a function of the scalar shear rate. Using experimental data of VWF unfolding in pure shear flow, we fix the parameters for VWF's unfolding propensity and the maximum VWF length, so that the protein is half unfolded at a shear rate of approximately 5000 s - 1 . We then use the theoretical model to predict VWF's behaviour in two complex flows where experimental data are challenging to obtain: pure elongational flow and stenotic arterial flow. In pure elongational flow, our model predicts that VWF is 50% unfolded at approximately 2000 s - 1 , matching the established hypothesis that VWF unfolds at lower shear rates in elongational flow than in shear flow. We demonstrate the sensitivity of this elongational flow prediction to the value of maximum VWF length used in the model, which varies significantly across experimental studies, predicting that VWF can unfold between 2000 and 3200 s - 1 depending on the selected value. Finally, we examine VWF dynamics in a range of idealised arterial stenoses, predicting the relative extension of VWF in elongational flow structures in the centre of the artery compared to high shear regions near the arterial walls. [ABSTRACT FROM AUTHOR]

Machine learning models are increasingly being used to estimate "brain age" from neuroimaging data. The gap between chronological age and the estimated brain age gap (BAG) is potentially a measure of accelerated and resilient brain aging. Brain age calculated in this fashion has been shown to be associated with mortality, measures of physical function, health, and disease. Here, we estimate the BAG using a voxel-based elastic net regression approach, and then, we investigate its associations with mortality, cognitive status, and measures of health and disease in participants from Atherosclerosis Risk in Communities (ARIC) study who had a brain MRI at visit 5 of the study. Finally, we used the SOMAscan assay containing 4877 proteins to examine the proteomic associations with the MRI-defined BAG. Among N = 1849 participants (age, 76.4 (SD 5.6)), we found that increased values of BAG were strongly associated with increased mortality and increased severity of the cognitive status. Strong associations with mortality persisted when the analyses were performed in cognitively normal participants. In addition, it was strongly associated with BMI, diabetes, measures of physical function, hypertension, prevalent heart disease, and stroke. Finally, we found 33 proteins associated with BAG after a correction for multiple comparisons. The top proteins with positive associations to brain age were growth/differentiation factor 15 (GDF-15), Sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SEVP 1), matrilysin (MMP7), ADAMTS-like protein 2 (ADAMTS), and heat shock 70 kDa protein 1B (HSPA1B) while EGF-receptor (EGFR), mast/stem-cell-growth-factor-receptor (KIT), coagulation-factor-VII, and cGMP-dependent-protein-kinase-1 (PRKG1) were negatively associated to brain age. Several of these proteins were previously associated with dementia in ARIC. These results suggest that circulating proteins implicated in biological aging, cellular senescence, angiogenesis, and coagulation are associated with a neuroimaging measure of brain aging. [ABSTRACT FROM AUTHOR]

The microvasculature, which makes up the majority of the cardiovascular system, plays a crucial role in the process of thrombosis, with the pathological formation of blood clots inside blood vessels. Since blood microflow conditions significantly influence platelet activation and thrombosis, accurately mimicking the structure of bifurcating microvascular networks and emulating local physiological blood flow conditions are valuable for understanding blood clot formation. In this work, we present an in vitro model for blood clotting in microvessels, focusing on 3D bifurcations that align with Murray's law, which guides vascular networks by maintaining a constant wall shear rate throughout. Using these models, we demonstrate that microvascular bifurcations act as sites facilitating thrombus formation compared to straight models. Additionally, by culturing endothelial cells on the luminal surfaces of the models, we show the potential of using our in vitro platforms to recapitulate the initial clotting in diseases involving endothelial dysfunction, such as Thrombotic Thrombocytopenic Purpura. [ABSTRACT FROM AUTHOR]

Background: Type 2B von Willebrand disease (VWD) is a less common subtype and is difficult to diagnose. This case report and literature review highlights a rare neonatal onset of type 2B VWD initially misdiagnosed as neonatal alloimmune thrombocytopenia (NAIT). Methods: The neonate presented with severe thrombocytopenia and was unresponsive to NAIT treatments. Genetic testing was conducted because of the unclear family history of thrombocytopenia. Results: Next-generation sequencing revealed a p.Arg1306Trp von Willebrand factor variant, confirming type 2B VWD. Conclusions: This study underscores the critical role of genetic testing in diagnosing challenging cases of neonatal thrombocytopenia, irrespective of family history, and aims to elucidate the clinical manifestations and course of neonatal onset type 2B VWD [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Patients with von Willebrand disease (VWD) require administration of von Willebrand factor (VWF) concentrates peri‐operatively. Concerns about FVIII accumulation after repetitive injections of a 1:1 ratio VWF/FVIII clotting factor concentrate (CFC) led this study to explore the recovery and FVIII accumulation over time.This monocentre study examined patients with VWD receiving perioperative 1:1 ratio CFC infusions. CFC dosing was based on body weight and endogenous VWF/FVIII activity. FVIII and VWF activity was monitored at T0 (baseline), T1 (15 min postinfusion), and trough levels at T2‐T6 (24‐120 h).We included 125 patients, undergoing 125 procedures (63 major surgeries, 62 minor), with a median of two CFC infusions (IQR 1–3). With a mean administered dose of 35.7 IU/kg CFC, recovery rates of FVIII and VWF were 2.6 IU/dL per IU/kg and 2.4 IU/dL per IU/kg, respectively. Mean FVIII levels at T0 were 62 (SD 51.9), T1: 164 (SD 80.4), T2: 155 (SD 62.8), T3: 162 (SD 59.8), T4: 124 (SD 78.4), and T5: 120 (SD 65.3) IU/dL. Mean VWF activity levels at T0 were 29 (SD 25.0), T1: 133 (SD 43.7), T2: 92 (SD 37.2), and T3: 86 (SD 37.5) IU/dL. Subgroup analysis in 47 patients with more than three infusions, showed no accumulation of mean FVIII levels.This perioperative study demonstrated excellent FVIII and VWF recovery of a 1:1 ratio VWF product in patients with VWD. Stable FVIII and VWF activity levels were observed after repeated infusions, without accumulation. Most major surgeries required only three CFC infusions. [ABSTRACT FROM AUTHOR]

Trauma is the leading cause of death in individuals up to 45 years of age. Alterations in platelet function are a critical component of trauma-induced coagulopathy (TIC), yet these changes and the potential resulting dysfunction is incompletely understood. The lack of clinical assays available to explore platelet function in this patient population has hindered detailed understanding of the role of platelets in TIC. The objective of this study was to assess trauma patient ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model. We hypothesized that trauma patients would have flow-regime dependent alterations in platelet function. Blood was collected from trauma patients with level I activations (N = 34) within 60 min of hospital arrival, as well as healthy volunteer controls (N = 10). Samples were perfused through a microfluidic model of injury at venous and arterial shear rates, and a subset of experiments were performed after incubation with fluorescent anti-CD41 to quantify platelets. Complete blood counts were performed as well as plasma-based assays to quantify coagulation times, fibrinogen, and von Willebrand factor (VWF). Exploratory correlation analyses were employed to identify relationships with microfluidic hemostatic parameters. Trauma patients had increased microfluidic bleeding times compared to healthy controls. While trauma patient samples were able to deposit a substantial amount of clot in the model injury site, the platelet contribution to microfluidic hemostasis was attenuated. Trauma patients had largely normal hematology and plasma-based coagulation times, yet had elevated D-Dimer and VWF. Venous microfluidic bleeding time negatively correlated with VWF, D-Dimer, and mean platelet volume (MPV), while arterial microfluidic bleeding time positively correlated with oxygenation. Arterial clot growth rate negatively correlated with red cell count, and positively with mean corpuscular volume (MCV). We observed changes in clot composition in trauma patient samples reflected by significantly diminished platelet contribution, which resulted in reduced hemostatic function in a microfluidic model of vessel injury. We observed a reduction in platelet clot contribution under both venous and arterial flow ex vivo in trauma patient samples. While our population was heterogenous and had relatively mild injury severity, microfluidic hemostatic parameters correlated with different patient-specific data depending on the flow setting, indicating potentially differential mechanistic pathways contributing to platelet hemostatic capacity in the context of TIC. These data were generated with the goal of identifying key features of platelet dysfunction in bleeding trauma patients under conditions of flow and to determine if these features correlate with clinically available metrics, thus providing preliminary surrogate markers of physiological platelet dysfunction to be further studied across larger cohorts. Future studies will continue to explore those relationships and further define mechanisms of TIC and their relationship with patient outcomes. [ABSTRACT FROM AUTHOR]

Von Willebrand factor (VWF) is a multimer with a variable number of protomers, each of which is a head-to-head dimer of two multi-domain monomers. VWF responds to shear through the unfolding and extension of distinct domains, thereby mediating platelet adhesion and aggregation to the injured blood vessel wall. VWF's C1-6 segment uncoils and then the A2 domain unfolds and extends in a hierarchical and sequential manner. However, it is unclear whether there is any reservoir of further extensibility. Here, we explored the presence of cryptic extensibility in VWF by nanodissecting individual, pre-stretched multimers with atomic force microscopy (AFM). The AFM cantilever tip was pressed into the surface and moved in a direction perpendicular to the VWF axis. It was possible to pull out protein loops from VWF, which resulted in a mean contour length gain of 217 nm. In some cases, the loop became cleaved, and a gap was present along the contour. Frequently, small nodules appeared in the loops, indicating that parts of the nanodissected VWF segment remained folded. After analyzing the nodal structure, we conclude that the cryptic extensibility lies within the C1-6 and A1-3 regions. Cryptic extensibility may play a role in maintaining VWF's functionality in extreme shear conditions. [ABSTRACT FROM AUTHOR]

von Willebrand disease (VWD) is a very heterogenous disease, resulting in different phenotypes and different degrees of bleeding severity. Established therapies (i.e., desmopressin, antifibrinolytic agents, hormone therapy for heavy menstrual bleeding, and von Willebrand factor [VWF] concentrates) may work in some subtypes, but not in all patients. In recent years, progress has been made in improving the diagnosis of VWD subtypes, allowing for more specific therapy. The impact of VWD on women's daily lives has also come to the fore in recent years, with hormone therapy, tranexamic acid, or recombinant VWF as treatment options. New treatment approaches, including the replacement of lacking factor VIII (FVIII) function, may work in those subgroups affected by severe FVIII deficiency. Reducing the clearance of VWF is an alternative treatment pathway; for example, rondaptivon pegol is a VWFA1 domain-binding aptamer which not only improves plasma VWF/FVIII levels, but also corrects platelet counts in thrombocytopenic type 2B VWD patients. These approaches are currently in clinical development, which will be the focus of this review. In addition, half-life extension methods are also important for the improvement of patients' quality of life. Targeting specific mutations may further lead to personalized treatments in the future. Finally, a few randomized controlled trials, although relatively small, have been published in recent years, aiming to achieve a higher level of evidence in future guidelines. [ABSTRACT FROM AUTHOR]

Introduction: Gastrointestinal (GI) bleeding events (BEs) in von Willebrand disease (VWD) are difficult to diagnose and often recurrent. Limited data from clinical trials has led to lack of consensus on treatment options. Aim: Describe current treatments and outcomes for GI BEs in people with VWD. Methods: This retrospective, observational, multicentre chart review study was conducted from January 2018 through December 2019 and included patients with inherited VWD with ≥1 GI BE in the preceding 5 years. Baseline characteristics, number and aetiology of BEs, associated GI‐specific morbidities/lesions, treatment and outcomes were analysed descriptively. Results: Sixty bleeds were reported in 20 patients with type 1 (20%), type 2 (50%) and type 3 (30%) VWD. During the 5‐year study period, 31 (52%) BEs had one identified or suspected cause; multiple causes were reported in 11 (18%). Most GI BEs (72%) were treated with a combination of von Willebrand factor (VWF), antifibrinolytics and/or other haemostatic or non‐haemostatic treatments. Time to resolution did not differ by VWF treatment use; however, BEs treated with non‐VWF treatments tended to resolve later. In patients with GI‐specific morbidities/lesions, 84% resolved with first‐line treatment; time to resolution tended to be longer than in patients without such morbidities/lesions. Thirteen BEs occurred in patients receiving prophylaxis and 47 in patients receiving on‐demand treatment; 18 BEs resulted in a switch to prophylaxis after bleed resolution. Conclusions: This study confirms the unmet need for the management of recurrent GI BEs in people with VWD and the need for prospective data, especially on prophylaxis. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Vigilant monitoring for postoperative complications, including bleeding and dysrhythmia, is crucial in patients with craniosynostosis syndromes like Crouzon syndrome undergoing craniofacial surgery, with a thorough evaluation, including coagulation tests, assisting in diagnosing underlying conditions such as von Willebrand disease subtype 1 to inform appropriate management strategies. Crouzon syndrome is a rare genetic disorder affecting craniofacial structures. Its etiology is the premature fusion of cranial sutures. The LeFort III advancement surgery is a commonly used approach to correct malformations related to midface hypoplasia. Complications following surgical treatment of craniosynostosis and craniofacial syndromes can include both intracranial and extracranial problems. Reporting of this syndrome and the surgery complications, in addition to consideration of other differential diagnoses, can help improve the treatment plan and surgery outcomes. The aim of the article is to report a 14‐year‐old female with Crouzon syndrome who underwent the modified LeFort III osteotomy and developed unexpected massive bleeding during the surgery. Post‐surgery, she experienced complications including dysrhythmia, hypothermia, and cyanosis. Treatment included fluid therapy, blood transfusions, and antibiotic therapy for suspected septic shock. Differential diagnosis was disseminated intravascular coagulation but was ruled out. Post‐discharge, coagulation tests suggested von Willebrand disease subtype 1 as the diagnosis. Excessive bleeding during surgery for craniosynostosis syndromes is a significant and concerning issue in the surgical management of Crouzon syndrome. For patients with von Willebrand disease who are candidates for elective surgeries, von Willebrand factor concentrates or recombinant von Willebrand factor can be used. [ABSTRACT FROM AUTHOR]

Allogeneic haematopoietic stem cell transplantation (allo‐HSCT) can potentially cure malignant blood disorders and benign conditions such as haemoglobinopathies and immunologic diseases. However, allo‐HSCT is associated with significant complications. The most common and debilitating among them is graft‐versus‐host disease (GVHD). In GVHD, donor‐derived T cells mount an alloimmune response against the recipient. The alloimmune response involves several steps, including recognition of recipient antigens, activation and proliferation of T cells in secondary lymphoid organs, and homing into GVHD‐targeted organs. Adhesion molecules on T cells and endothelial cells mediate homing of T cells into lymphoid and non‐lymphoid tissues. In this study, we showed that Von Willebrand factor (VWF), an adhesion molecule secreted by activated endothelial cells, plays an important role in mouse models of GVHD. We investigated the effect of the VWF‐cleaving protease ADAMTS13 on GVHD. We found that ADAMTS13 reduced the severity of GVHD after bone marrow transplantation from C57BL6 donor to BALB/C recipient mice. A recombinant VWF‐A2 domain peptide also reduced GVHD in mice. We showed that ADAMTS13 and recombinant VWF‐A2 reduced the binding of T cells to endothelial cells and VWF in vitro, and reduced the number of T cells in lymph nodes, Peyer's patches and GVHD‐targeted organs in vivo. We identified LFA‐1 (αLβ2) as the binding site of VWF on T cells. Our results showed that blocking T‐cell homing by ADAMTS13 or VWF‐A2 peptide reduced the severity of the GVHD after allo‐HSCT, a potentially novel method for treating and preventing GVHD. [ABSTRACT FROM AUTHOR]

Purpose: The crosstalk between hepatocellular carcinoma (HCC) cells and hepatic stellate cells (HSCs) is one of the important mechanisms of liver cancer metastasis. The relationship between liver cancer metastasis and glycolysis has been extensively studied recently. However, the role of von Willebrand factor (vWF) mediated glycolysis mechanism in liver cancer metastasis is currently unknown. Methods: Western blot was used to verify the expression of vWF in HCC cells. PAS staining, glycogen and L-lactate content assays were used to reflect cellular glycolysis levels. The ability of cell migration was explored by Wound-healing and Transwell assays. Besides, the effect of vWF on the progression of HCC in vivo was also studied using subcutaneous xenograft model. Results: vWF derived from HCC cells promoted tumor migration by mediating glycolysis. Besides, vWF participated in the crosstalk between HCC cells and HSCs. HCC cells activated HSCs through vWF-mediated TGFB1 expression and secretion, and activated HSCs upregulated vWF expression in HCC cells through IL-6 secretion feedback. Further, in vitro and in vivo experiments also confirmed the importance of the JAK1/vWF/TGFB1 axis in regulating HSCs-derived IL-6 mediated HCC migration and growth. Conclusion: In summary, this article demonstrated that IL-6 released from hepatic stellate cells enhanced glycolysis and migration ability of liver cancer cells by activating JAK1/vWF/TGFB1 axis which may also be a potential target for inhibiting liver cancer metastasis. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of intracoronary prourokinase thrombolysis combined with emergency percutaneous coronary intervention (PCI) on myocardial perfusion and vascular endothelial function in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: A total of 104 patients with STEMI were collected from August 2020 to August 2022, and were divided into control group and observation group in a random manner. The control group received PCI directly, and the observation group received intracoronary prourokinase thrombolytic therapy before PCI. The treatment effects were evaluated by measuring the cardiac function indexes, including left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and left ventricular ejection fraction (LVEF), the TIMI myocardial perfusion grade, the vascular endothelial indexes, including soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1), the von Willebrand factor (vWF), the myocardial injury indexes, including cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), and lactate dehydrogenase (LDH), and the inflammatory factors, including myeloperoxidase (MPO), C-reactive protein (CRP), and interleukin-6 (IL-6). Furthermore, the treatment safety was assessed by recording the incidence of major MACE events, 6 months after the operation. Results: After treatment, LVEDD and LVESD were lower in the observation group than in the control group, and LVEF was higher (p < 0.05). The TIMI myocardial perfusion grade in the observation group was higher than in the control group, after treatment (p < 0.05). The levels of sICAM-1, sVCAM-1, and vWF were higher in the observation group than in the control group (p < 0.05). The levels of cTnI, CK-MB, and LDH in the observation group were lower than those in the control group, 24 hours after surgery. At 3 days after surgery, MPO was lower in the observation group than in the control group, and CRP and IL-6 were higher (p < 0.05). The incidence of major MACE events in the observation group was lower than that in the control group, 6 months after surgery (p < 0.05). There was 1 case of puncture site bleeding in the observation group, 1 case of puncture site bleeding and 1 case of subcutaneous ecchymosis in the control group, but no serious bleeding events, such as internal bleeding or cerebral hemorrhage, in the two groups. Conclusions: Intracoronary prourokinase thrombolytic therapy combined with emergency PCI can promote the recovery of cardiac function, improve myocardial perfusion and vascular endothelial function, and reduce inflammation and the incidence of major postoperative MACE events in acute STEMI patients. [ABSTRACT FROM AUTHOR]

Abstract Caplacizumab reduces the need for therapeutic plasma exchange (TPE) during treatment for thrombotic thrombocytopenic purpura (TTP), associates with fewer required TPE, and shortens hospital stay. It is therefore recommended as part of standard care. However, the treatment effects on hemostasis may complicate initial management. We present a case of a woman with immune‐mediated TTP who developed an intrathoracic hemorrhage on caplacizumab treatment after replacement of her central venous catheter. Reduced von Willebrand factor (vWF):glycoprotein Ib mutant (GPIbM) activity was reversed using vWF concentrate and the bleeding stopped. Unfortunately, vWF substitution in combination with caplacizumab discontinuation likely contributed to subsequent extensive venous thromboembolism. Risk‐reducing strategies against both bleeding and thrombosis are crucial during caplacizumab treatment, and emergency vWF substitution increases the already high risk of thrombosis associated with TPE.

Abstract Background SARS-CoV-2 is a systemic disease that affects endothelial function and leads to coagulation disorders, increasing the risk of mortality. Blood levels of endothelial biomarkers such as Von Willebrand Factor (VWF), Thrombomodulin or Blood Dendritic Cell Antigen-3 (BDCA3), and uUokinase (uPA) increase in patients with severe disease and can be prognostic indicators for mortality. Therefore, the aim of this study was to determine the effect of VWF, BDCA3, and uPA levels on mortality. Methods From May 2020 to January 2021, we studied a prospective cohort of hospitalized adult patients with polymerase chain reaction (PCR)-confirmed COVID-19 with a SaO2 ≤ 93% and a PaO2/FiO2 ratio

Abstract Background Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is an ultra-rare, autosomal-dominant small vessel disease caused by loss-of-function variants in the gene TREX1. Recently, elevated serum levels of von Willebrand Factor Antigen (vWF-Ag) pointed to an underlying endotheliopathy, and microvascular ischemia was suggested to contribute to the neurodegeneration in RVCL-S. Aim of this study was to further elucidate the endotheliopathy in RVCL-S. Methods vWF-Ag and ADAMTS-13 activity were repeatedly measured in two patients with genetically confirmed RVCL-S. Renal biopsy of both RVCL-S patients and autoptic brain, renal, hepatic, and pulmonary specimen of one patient with RVCL-S were examined immunohistochemically in comparison to matched controls. In addition, cerebral methylome analysis was performed in the autoptic brain specimen calculating differentially methylated positions compared to controls. Results While vWF-Ag and activity was strongly elevated, ADAMTS-13 activity was low in RVCL-S and further decreased over the course of the disease. Autoptic brain specimen showed signs of thromboinflammation in cerebral small vessels, and vWF-Ag staining was strongly positive in cerebral and renal small vessels in RVCL-S, while only a light to moderate vWF-Ag staining was found in controls. Cerebral methylome analysis yielded 115 differentially methylated CpGs (p

Abstract Background Von Willebrand factor (vWF) plays a crucial role in hemostasis, acting as a key factor for platelet adhesion/aggregation and as a transport protein for coagulation factor VIII. vWF is secreted as a giant multimer, and it undergoes shear stress-dependent cleavage by a specific metalloproteinase in plasma. Among vWF multimers, high-molecular-weight (large) multimers are essential for hemostasis. Acquired von Willebrand syndrome, linked to various conditions, is a hemostatic disorder due to reduced vWF activity. Extracorporeal membrane oxygenation (ECMO), utilized recently for out-of-hospital cardiac arrest patients, generates high shear stress inside the pump. This stress may induce a conformational change in vWF, enhancing cleavage by a specific metalloproteinase and thereby reducing vWF activity. However, no study has investigated the effects of ECMO on vWF-related factors in patients receiving or not receiving ECMO. This study aimed to elucidate the relationship between ECMO treatment and acquired von Willebrand syndrome-related factors in patients with out-of-hospital cardiac arrest. Methods This study included patients with cardiogenic out-of-hospital cardiac arrest admitted to our hospital. The patients were categorized into two groups (ECMO and non-ECMO) based on the presence or absence of ECMO treatment. Plasma samples were collected from patients admitted to the emergency department (days 0–4). The vWF antigen (vWF: Ag), vWF ristocetin cofactor activity (vWF: RCo), and factor VIII activity were measured. Additionally, a large multimer of vWF was evaluated through vWF multimer analysis, utilizing western blotting to probe vWF under non-reducing conditions. Results The ECMO and non-ECMO groups included 10 and 22 patients, respectively. The median ECMO treatment in the ECMO group was 64.6 h. No differences in vWF: Ag or factor VIII activity were observed between the two groups during the observation period. However, the ECMO group exhibited a decrease in large vWF multimers and vWF: RCo during ECMO. Strong correlations were observed between vWF: RCo and vWF: Ag in both groups, although the relationships were significantly different between the two groups. Conclusions ECMO treatment in patients with out-of-hospital cardiac arrest resulted in the loss of large vWF multimers and decreased vWF activity. Hence, decreased vWF activity should be considered as a cause of bleeding during ECMO management.

Abstract Background Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI). Methods Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21. Results Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p 50% (p

Abstract ADAMTS13, a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13, regulates the length of Von Willebrand factor (VWF) multimers and their platelet-binding activity. ADAMTS13 is constitutively secreted as an active protease and is not inhibited by circulating protease inhibitors. Therefore, the mechanisms that regulate ADAMTS13 protease activity are unknown. We performed an unbiased proteomics screen to identify ligands of ADAMTS13 by optimizing the application of BioID to plasma. Plasma BioID identified 5 plasma proteins significantly labeled by the ADAMTS13-birA* fusion, including VWF and plasminogen. Glu-plasminogen, Lys-plasminogen, mini-plasminogen, and apo(a) bound ADAMTS13 with high affinity, whereas micro-plasminogen did not. None of the plasminogen variants or apo(a) bound to a C-terminal truncation variant of ADAMTS13 (MDTCS). The binding of plasminogen to ADAMTS13 was attenuated by tranexamic acid or ε-aminocaproic acid, and tranexamic acid protected ADAMTS13 from plasmin degradation. These data demonstrate that plasminogen is an important ligand of ADAMTS13 in plasma by binding to the C-terminus of ADAMTS13. Plasmin proteolytically degrades ADAMTS13 in a lysine-dependent manner, which may contribute to its regulation. Adapting BioID to identify protein-interaction networks in plasma provides a powerful new tool to study protease regulation in the cardiovascular system.

Background: The safety of laparoscopic hepatectomy for inherited coagulation disorders is unclear; however, the safety of open hepatectomy has been reported in several studies. Herein, we report the first case of a laparoscopic hepatectomy for a patient with von Willebrand Disease (VWD). Case presentation: A 76-year-old male with a history of chronic hepatitis C and VWD type 2B was advised surgical resection of a 4 cm hepatocellular carcinoma in segment 7 of the liver. The patient was diagnosed with VWD in his 40 s due to gastrointestinal bleeding caused by gastric erosion. The von Willebrand factor (VWF) ristocetin cofactor activity was 30%, and VWF large multimer deficiency and increased ristocetin-induced platelet agglutination were observed. The preoperative platelet count was reduced to 3.5 × 104/μL; however, preoperative imaging findings had no evidence of liver cirrhosis, such as any collateral formations and splenomegaly. The indocyanine green retention rate at 15 min was 10%, and his Child–Pugh score was 5 (classification A). Perioperatively, VWF/factor VIII was administered in accordance with our institutional protocol. A laparoscopic partial hepatectomy of the right posterior segment was performed. The most bleeding during surgery occurred during the mobilization of the right lobe of the liver due to inflammatory adhesion between the retroperitoneum and the tumor. Bleeding during parenchymal transection was controlable. The duration of hepatic inflow occlusion was 65 min. The surgical duration was 349 min, and the estimated blood loss was 2150 ml. Four units of red blood cells and fresh frozen plasma were transfused at the initiation of parenchymal transection, and 10 units of platelets were transfused at the end of the parenchymal transection. On postoperative day 1, the transection surface drainage fluid became hemorrhagic, and emergency contrast-enhanced computed tomography showed extravasation in the greater omentum. Percutaneous transcatheter arterial embolization of the omental branch of the right gastroepiploic artery was performed. No further postoperative interventions were required. The patient was discharged on postoperative day 14. Conclusion: The indications for laparoscopic hepatectomy in patients with VWD should be carefully considered, and an open approach may still be the standard approach for patients with VWD. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy is a primary local treatment for tumors, yet it may lead to complications such as radiation-induced heart disease (RIHD). Currently, there is no standardized approach for preventing RIHD. Dexmedetomidine (Dex) is reported to have cardio-protection effects, while its role in radiation-induced myocardial injury is unknown. In the current study, we aimed to evaluate the radioprotective effect of dexmedetomidine in X-ray radiation-treated mice. Methods: 18 male mice were randomized into 3 groups: control, 16 Gy, and 16 Gy + Dex. The 16 Gy group received a single dose of 16 Gy X-ray radiation. The 16 Gy + Dex group was pretreated with dexmedetomidine (30 µg/kg, intraperitoneal injection) 30 min before X-ray radiation. The control group was treated with saline and did not receive X-ray radiation. Myocardial tissues were collected 16 weeks after X-ray radiation. Hematoxylin-eosin staining was performed for histopathological examination. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining was performed to assess the state of apoptotic cells. Immunohistochemistry staining was performed to examine the expression of CD34 molecule and von Willebrand factor. Besides, western blot assay was employed for the detection of apoptosis-related proteins (BCL2 apoptosis regulator and BCL2-associated X) as well as autophagy-related proteins (microtubule-associated protein 1 light chain 3, beclin 1, and sequestosome 1). Results: The findings demonstrated that 16 Gy X-ray radiation resulted in significant changes in myocardial tissues, increased myocardial apoptosis, and activated autophagy. Pretreatment with dexmedetomidine significantly protects mice against 16 Gy X-ray radiation-induced myocardial injury by inhibiting apoptosis and autophagy. Conclusion: In summary, our study confirmed the radioprotective effect of dexmedetomidine in mitigating cardiomyocyte apoptosis and autophagy induced by 16 Gy X-ray radiation. [ABSTRACT FROM AUTHOR]

Background: Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is an ultra-rare, autosomal-dominant small vessel disease caused by loss-of-function variants in the gene TREX1. Recently, elevated serum levels of von Willebrand Factor Antigen (vWF-Ag) pointed to an underlying endotheliopathy, and microvascular ischemia was suggested to contribute to the neurodegeneration in RVCL-S. Aim of this study was to further elucidate the endotheliopathy in RVCL-S. Methods: vWF-Ag and ADAMTS-13 activity were repeatedly measured in two patients with genetically confirmed RVCL-S. Renal biopsy of both RVCL-S patients and autoptic brain, renal, hepatic, and pulmonary specimen of one patient with RVCL-S were examined immunohistochemically in comparison to matched controls. In addition, cerebral methylome analysis was performed in the autoptic brain specimen calculating differentially methylated positions compared to controls. Results: While vWF-Ag and activity was strongly elevated, ADAMTS-13 activity was low in RVCL-S and further decreased over the course of the disease. Autoptic brain specimen showed signs of thromboinflammation in cerebral small vessels, and vWF-Ag staining was strongly positive in cerebral and renal small vessels in RVCL-S, while only a light to moderate vWF-Ag staining was found in controls. Cerebral methylome analysis yielded 115 differentially methylated CpGs (p < 0.05) in the deceased RVCL-S patient compared to the eight controls without brain pathology. One of the hypomethylated genes coded for ADAMTS-13 (p = 0.00056). Conclusions: These findings point to an imbalance of the vWF – ADAMTS-13 axis in patients with RVCL-S, that may finally lead to an accumulation of vWF-Ag in renal and cerebral small vessels. Elevated vWF-Ag levels may serve as an early serum marker reflecting disease activity. If confirmed, therapeutic approaches might aim at an inhibition of vWF-Ag or increase of ADAMTS-13 activity in the future. [ABSTRACT FROM AUTHOR]

Summary: Background and Aims: The prognostic performance of von Willebrand factor (VWF) may vary across clinical stages of advanced chronic liver disease (ACLD). Therefore, we investigated the evolution of VWF and other biomarkers throughout the full ACLD spectrum and evaluated their stage‐specific prognostic utility. Methods: We retrospectively included Viennese ACLD patients with available information on hepatic venous pressure gradient (HVPG), C‐reactive protein (CRP)/VWF levels and outcomes. ACLD stages were defined according to D'Amico et al. We included an external validation cohort from Padua. Results: We observed gradual increases in VWF throughout ACLD stages. In contrast, HVPG levelled off in decompensated ACLD (dACLD), whereas MELD showed only minor changes in the early stages and CRP did not increase until stage 3. VWF was associated with hepatic decompensation/liver‐related death in compensated ACLD (cACLD) in a fully adjusted model, while it was not independently predictive of ACLF/liver‐related death in dACLD. After backward selection, HVPG/CRP/VWF remained the main predictors of hepatic decompensation/liver‐related death in cACLD. Notably, the performance of the non‐invasive CRP/VWF‐based model was comparable to invasive HVPG‐based models (C‐index:0.765 ± 0.034 vs. 0.756 ± 0.040). The discriminative ability of the CRP/VWF‐based model was confirmed in an external validation cohort using another VWF assay which yielded systematically lower values. Conclusion: VWF is the only biomarker that gradually increases across all ACLD stages. It is of particular prognostic value in cACLD, where a CRP/VWF‐based model is equivalent to an invasive HVPG‐based model. Systematic differences in VWF underline the importance of interlaboratory surveys. Moreover, our findings reinforce the notion that, already in cACLD, inflammation is a key disease‐driving mechanism. [ABSTRACT FROM AUTHOR]

Type V collagen is considered to be a crucial minor collagen in fish skin with unique physiological functions. In this research, the cDNAs of three procollagens (Tacol5a1, Tacol5a2, and Tacol5a3) in type V collagen were cloned from the skin of shortbill spearfish (Tetrapturus angustirostris). The open reading frames (ORFs) of Tacol5a1, Tacol5a2, and Tacol5a3 contained 5991, 4485, and 5607 bps, respectively, encoding 1997, 1495, and 1869 amino acid residues. Each of the deduced amino acid sequences of procollagens contained a signal peptide and a fibrillar collagen C-terminal domain (COLFI). A conserved thrombospondin-like N-terminal domain (TSPN) was found at the N-terminus of Tacol5a1 and 5a3 procollagens, whereas a von Willebrand factor (VWC) was found at the N-terminus of Tacol5a2 procollagen. Tacol5a1, Tacol5a2, and Tacol5a3 had their theoretical isoelectric points of 5.06, 6.75, and 5.76, respectively, and predicted molecular weights of 198,435.60, 145,058.48, and 189,171.18, respectively. The phylogenetic tree analysis revealed that Tacol5a1 of shortbill spearfish clustered with that of yellow perch (Perca flavescens) instead of broadbill swordfish (Xiphias gladius). In addition, type V collagen was extracted from the shortbill spearfish skin. The in silico method demonstrated that shortbill spearfish type V collagen has a high potential for angiotensin-converting enzyme (ACE) inhibition activity (79.50%), dipeptidyl peptidase IV inhibition (74.91%) activity, and antithrombotic activity (46.83%). The structural clarification and possible functional investigation in this study provide the foundation for the applications of exogenous type V collagen derived from fish sources. [ABSTRACT FROM AUTHOR]

Von Willebrand disease is an inherited disorder characterized by deficiency of von Willebrand factor, which contributes to platelet adhesion to the endothelium. Patients with coagulation disorders present a challenge at the time of surgery due to the high risk of presenting heavy bleeding within the procedure or postoperative hematomas. We present a case of a 56-year-old woman with Type 1 von Willebrand's disease who was scheduled for breast explantation with autologous reconstruction, due to the presence of long-standing breast implants. The case was satisfactorily managed by a multidisciplinary team formed by plastic surgery, hematology, and anesthesiology, individualizing the management for the patient's case, obtaining good results and a safe procedure. [ABSTRACT FROM AUTHOR]

Under different pathophysiological conditions, endothelial cells lose endothelial phenotype and gain mesenchymal cell-like phenotype via a process known as endothelial-to-mesenchymal transition (EndMT). At the molecular level, endothelial cells lose the expression of endothelial cell-specific markers such as CD31/platelet-endothelial cell adhesion molecule, von Willebrand factor, and vascular-endothelial cadherin and gain the expression of mesenchymal cell markers such as α-smooth muscle actin, N-cadherin, vimentin, fibroblast specific protein-1, and collagens. EndMT is induced by numerous different pathways triggered and modulated by multiple different and often redundant mechanisms in a context-dependent manner depending on the pathophysiological status of the cell. EndMT plays an essential role in embryonic development, particularly in atrioventricular valve development; however, EndMT is also implicated in the pathogenesis of several genetically determined and acquired diseases, including malignant, cardiovascular, inflammatory, and fibrotic disorders. Among cardiovascular diseases, aberrant EndMT is reported in atherosclerosis, pulmonary hypertension, valvular disease, fibroelastosis, and cardiac fibrosis. Accordingly, understanding the mechanisms behind the cause and/or effect of EndMT to eventually target EndMT appears to be a promising strategy for treating aberrant EndMT-associated diseases. However, this approach is limited by a lack of precise functional and molecular pathways, causes and/or effects, and a lack of robust animal models and human data about EndMT in different diseases. Here, we review different mechanisms in EndMT and the role of EndMT in various cardiovascular diseases. [ABSTRACT FROM AUTHOR]

An excessive von Willebrand factor (VWF) secretion, coupled with a moderate to severe deficiency of ADAMTS13 activity, serves as a linking mechanism between inflammation to thrombosis. The former facilitates platelet adhesion to the vessel wall and the latter is required to cleave VWF multimers. As a result, the ultra-large VWF (UL-VWF) multimers released by Weibel–Palade bodies remain uncleaved. In this study, using a computational model based on first principles, we quantitatively show how the uncleaved UL-VWF multimers interact with the blood cells to initiate microthrombosis. We observed that platelets first adhere to unfolded and stretched uncleaved UL-VWF multimers anchored to the microvessel wall. By the end of this initial adhesion phase, the UL-VWF multimers and platelets make a mesh-like trap in which the red blood cells increasingly accumulate to initiate a gradually growing microthrombosis. Although high-shear rate and blood flow velocity are required to activate platelets and unfold the UL-VWFs, during the initial adhesion phase, the blood velocity drastically drops after thrombosis, and as a result, the wall shear stress is elevated near UL-VWF roots, and the pressure drops up to 6 times of the healthy condition. As the time passes, these trends progressively continue until the microthrombosis fully develops and the effective size of the microthrombosis and these flow quantities remain almost constant. Our findings quantitatively demonstrate the potential role of UL-VWF in coagulopathy. [ABSTRACT FROM AUTHOR]

Objectives: Acute pancreatitis (AP) is an inflammatory disease of the pancreas, and the prognosis of severe AP (SAP) is poor. The study aimed to identify promising biomarkers for predicting the occurrence and survival outcome of SAP patients. Materials and Methods: Two hundred and forty AP patients were retrospectively recruited, in which 72 cases with SAP. Blood test was done for collection of laboratory indicators. After treatment, the mortality of patients was recorded. Results: Patients in the SAP group had higher intensive care unit admissions and longer hospital stays (p <.001). Among laboratory parameters, significantly high values of C‐reactive protein (CRP), triglycerides and glucose (TyG) index, Von willebrand factor antigen (vWF:Ag) and D‐dimer were found in SAP groups relative to non‐SAP ones. Receiver operating characteristic curve indicated the good performance of CRP, TyG index, vWF:Ag and D‐dimer in SAP diagnosis. Among all SAP cases, 51 survived while 21 died. TyG index (odds ratio [OR] = 6.914, 95% confidence interval [CI] = 1.193–40.068, p =.028), vWF:Ag (OR = 7.441, 95% CI = 1.236–244.815, p =.028), and D‐dimer (OR = 7.987, 95% CI = 1.251–50.997, p =.028) were significantly related to survival outcome of SAP patients by multiple logistic regression analysis. Both TyG index and vWF showed favorable efficiency in predicting overall prognosis. The area under the curve for the multivariate model (PRE = −35.908 + 2.764 × TyG + 0.021 × vWF:Ag) was 0.909 which was greater than 0.9, indicating its excellent performance in prognosis prediction. Conclusion: CRP, TyG index, vWF:Ag, and D‐dimer values on admission may be potential clinical predictors of the development of SAP. Moreover, TyG index and vWF:Ag may be helpful to predict survival outcome. [ABSTRACT FROM AUTHOR]

Discovering macromolecules and understanding the associated mechanisms involved in underwater adhesion are essential for both studying the fundamental ecology of benthos in aquatic ecosystems and developing biomimetic adhesive materials in industries. Here, we employed quantitative proteomics to assess protein expression variations during the development of the distinct adhesive structure - stolon in the model fouling ascidian, Ciona robusta. We found 16 adhesive protein candidates with increased expression in the stolon, with ascidian adhesive protein 1 (AAP1) being particularly rich in adhesion-related signal peptides, amino acids, and functional domains. Western blot and immunolocalization analyses confirmed the prominent AAP1 signals in the mantle, tunic, stolon, and adhesive footprints, indicating the interfacial role of this protein. Surface coating and atomic force microscopy experiments verified AAP1′s adhesion to diverse materials, likely through the specific electrostatic and hydrophobic amino acid interactions with various substrates. In addition, molecular docking calculations indicated the AAP1′s potential for cross-linking via hydrogen bonds and salt bridges among Von Willebrand factor type A domains, enhancing its adhesion capability. Altogether, the newly discovered interfacial protein responsible for permanent underwater adhesion, along with the elucidated adhesion mechanisms, are expected to contribute to the development of biomimetic adhesive materials and anti-fouling strategies. Discovering macromolecules and studying their associated mechanisms involved in underwater adhesion are essential for understanding the fundamental ecology of benthos in aquatic ecosystems and developing innovative bionic adhesive materials in various industries. Using multidisciplinary analytical methods, we identified an interfacial protein - Ascidian Adhesive Protein 1 (AAP1) from the model marine fouling ascidian, Ciona robusta. The interfacial functions of AAP1 are achieved by electrostatic and hydrophobic interactions, and the Von Willebrand factor type A domain-based cross-linking likely enhances AAP1's interfacial adhesion. The identification and validation of the interfacial functions of AAP1, combined with the elucidation of adhesion mechanisms, present a promising target for the development of biomimetic adhesive materials and the formulation of effective anti-fouling strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Background and aims: A prothrombotic state was demonstrated in patients with Cushing's syndrome and is involved in the development and progression of cardiovascular and renal damage in hypertensive patients. This study was designed to examine the relationships between cortisol secretion and the hemostatic and fibrinolytic systems in hypertension. Methods: In 149 middle-aged, nondiabetic, essential hypertensive patients free of cardiovascular and renal complications, we measured hemostatic markers that express the spontaneous activation of the coagulation and fibrinolytic systems and assessed daily cortisol levels (8 AM, 3 PM, 12 AM; area under the curve, AUC-cortisol) together with the cortisol response to dexamethasone overnight suppression (DST-cortisol). Results: Plasma levels of D-dimer (D-dim), prothrombin fragment 1 + 2 (F1 + 2), and von Willebrand factor (vWF) were progressively and significantly higher across tertiles of AUC-cortisol and DST-cortisol, whereas no differences were observed in fibrinogen, tissue plasminogen activator, plasminogen activator inhibitor-1, antithrombin III, protein C, and protein S. D-dim, F1 + 2, and vWF were significantly and directly correlated with age and both AUC-cortisol and DST-cortisol. Multivariate regression analysis showed that both AUC-cortisol and DST-cortisol were related to plasma D-dim, F1 + 2, and vWF independently of age, body mass index, blood pressure, and renal function. Conclusion: Greater daily cortisol profile and cortisol response to overnight suppression are independently associated with a prothrombotic state in hypertensive patients and might contribute to the development of organ damage and higher risk of cardiovascular complications. [ABSTRACT FROM AUTHOR]

Endothelial hyperpermeability is pivotal in sepsis-associated multi-organ dysfunction. Increased von Willebrand factor (vWF) plasma levels, stemming from activated platelets and endothelium injury during sepsis, can bind to integrin αvβ3, exacerbating endothelial permeability. Hence, targeting this pathway presents a potential therapeutic avenue for sepsis. Recently, we identified isaridin E (ISE), a marine-derived fungal cyclohexadepsipeptide, as a promising antiplatelet and antithrombotic agent with a low bleeding risk. ISE's influence on septic mortality and sepsis-induced lung injury in a mouse model of sepsis, induced by caecal ligation and puncture, is investigated in this study. ISE dose-dependently improved survival rates, mitigating lung injury, thrombocytopenia, pulmonary endothelial permeability, and vascular inflammation in the mouse model. ISE markedly curtailed vWF release from activated platelets in septic mice by suppressing vesicle-associated membrane protein 8 and soluble N-ethylmaleide-sensitive factor attachment protein 23 overexpression. Moreover, ISE inhibited healthy human platelet adhesion to cultured lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs), thereby significantly decreasing vWF secretion and endothelial hyperpermeability. Using cilengitide, a selective integrin αvβ3 inhibitor, it was found that ISE can improve endothelial hyperpermeability by inhibiting vWF binding to αvβ3. Activation of the integrin αvβ3-FAK/Src pathway likely underlies vWF-induced endothelial dysfunction in sepsis. In conclusion, ISE protects against sepsis by inhibiting endothelial hyperpermeability and platelet-endothelium interactions. [ABSTRACT FROM AUTHOR]

Background: Enhanced platelet responses have been demonstrated in heartworm-infected (HWI) dogs; however, the cause and clinical implications of altered platelet function have not been fully elucidated. Objective: This study evaluated platelet function in HWI dogs. Methods: Anticoagulated whole blood collected from eight HWI and eight uninfected dogs was evaluated using turbidometric platelet aggregometry, a platelet function analyzer (PFA-100), a total thrombus analysis system (T-TAS), tissue factor-activated and tissue plasminogen activator modified thromboelastography (TF- and tPA-TEG), CBC, von Willebrand Factor activity, and fibrinogen concentrations. Platelet activation state and the presence of reticulated platelets were assessed via flow cytometric expression of P-selection (CD-62P) and thiazole orange staining. Results: Platelet aggregation responses to adenosine diphosphate (ADP, 10 μM) or collagen (20 μg/mL), PFA-100 closure times, and T-TAS occlusion times did not differ between groups. TEG values TF-R, tPA-R, TF-K, and TF-LY60 were decreased (P= .025, P= .047, P = .038, P = .025) and TF-MA, tPA-MA, TF-G, tPA-G and TF-alpha angle were increased (P < .04) in HWI dogs. HWI dogs had higher fibrinogen concentrations (465.6 ± 161 mg/dL vs 284.5 ± 38 mg/dL, P = .008) and eosinophil counts (0.686 ± 0.27 × 10³/μL vs 0.267 ± 0.20 × 10³/μL, P = .003). There was no difference in hematocrit, activation state, or percent of reticulated platelets. Non-activated reticulated platelets exhibited higher CD62P expression compared with mature platelets. Conclusions: Chronic canine heartworm disease was accompanied by hypercoagulability, hyperfibrinogenemia, and decreased fibrinolysis. Enhanced platelet activation was not identified in this group of HWI dogs. [ABSTRACT FROM AUTHOR]

Background: Von Willebrand factor (vWF) plays a crucial role in hemostasis, acting as a key factor for platelet adhesion/aggregation and as a transport protein for coagulation factor VIII. vWF is secreted as a giant multimer, and it undergoes shear stress-dependent cleavage by a specific metalloproteinase in plasma. Among vWF multimers, high-molecular-weight (large) multimers are essential for hemostasis. Acquired von Willebrand syndrome, linked to various conditions, is a hemostatic disorder due to reduced vWF activity. Extracorporeal membrane oxygenation (ECMO), utilized recently for out-of-hospital cardiac arrest patients, generates high shear stress inside the pump. This stress may induce a conformational change in vWF, enhancing cleavage by a specific metalloproteinase and thereby reducing vWF activity. However, no study has investigated the effects of ECMO on vWF-related factors in patients receiving or not receiving ECMO. This study aimed to elucidate the relationship between ECMO treatment and acquired von Willebrand syndrome-related factors in patients with out-of-hospital cardiac arrest. Methods: This study included patients with cardiogenic out-of-hospital cardiac arrest admitted to our hospital. The patients were categorized into two groups (ECMO and non-ECMO) based on the presence or absence of ECMO treatment. Plasma samples were collected from patients admitted to the emergency department (days 0–4). The vWF antigen (vWF: Ag), vWF ristocetin cofactor activity (vWF: RCo), and factor VIII activity were measured. Additionally, a large multimer of vWF was evaluated through vWF multimer analysis, utilizing western blotting to probe vWF under non-reducing conditions. Results: The ECMO and non-ECMO groups included 10 and 22 patients, respectively. The median ECMO treatment in the ECMO group was 64.6 h. No differences in vWF: Ag or factor VIII activity were observed between the two groups during the observation period. However, the ECMO group exhibited a decrease in large vWF multimers and vWF: RCo during ECMO. Strong correlations were observed between vWF: RCo and vWF: Ag in both groups, although the relationships were significantly different between the two groups. Conclusions: ECMO treatment in patients with out-of-hospital cardiac arrest resulted in the loss of large vWF multimers and decreased vWF activity. Hence, decreased vWF activity should be considered as a cause of bleeding during ECMO management. [ABSTRACT FROM AUTHOR]

Introduction: The pulmonary endothelium is the primary target of lung ischemia-reperfusion injury leading to primary graft dysfunction after lung transplantation. We hypothesized that treating damaged rat lungs by a transient heat stress during ex-vivo lung perfusion (EVLP) to elicit a pulmonary heat shock response could protect the endothelium from severe reperfusion injury. Methods: Rat lungs damaged by 1h warm ischemia were reperfused on an EVLP platform for up to 6h at a constant temperature (T°) of 37°C (EVLP37°C group), or following a transient heat stress (HS) at 41.5°C from 1 to 1.5h of EVLP (EVLPHS group). A group of lungs exposed to 1h EVLP only (pre-heating conditions) was added as control (Baseline group). In a first protocol, we measured lung heat sock protein expression (HSP70, HSP27 and Hsc70) at selected time-points (n=5/group at each time). In a second protocol, we determined (n=5/group) lung weight gain (edema), pulmonary compliance, oxygenation capacity, pulmonary artery pressure (PAP) and vascular resistance (PVR), the expression of PECAM-1 (CD31) and phosphorylation status of Src-kinase and VE-cadherin in lung tissue, as well as the release in perfusate of cytokines (TNFα, IL-1β) and endothelial biomarkers (sPECAM, von Willebrand Factor -vWF-, sE-selectin and sICAM-1). Histological and immunofluorescent studies assessed perivascular edema and formation of 3-nitrotyrosine (a marker of peroxinitrite) in CD31 lung endothelium. Results: HS induced an early (3h) and persisting expression of HSP70 and HSP27, without influencing Hsc70. Lungs from the EVLP37°C group developed massive edema, low compliance and oxygenation, elevated PAP and PVR, substantial release of TNFα, IL-1β, s-PECAM, vWF, E-selectin and s-ICAM, as well as significant Src-kinase activation, VE-cadherin phosphorylation, endothelial 3-NT formation and reduced CD31 expression. In marked contrast, all these alterations were either abrogated or significantly attenuated by HS treatment. Conclusion: The therapeutic application of a transient heat stress during EVLP of damaged rat lungs reduces endothelial permeability, attenuates pulmonary vasoconstriction, prevents src-kinase activation and VE-cadherin phosphorylation, while reducing endothelial peroxinitrite generation and the release of cytokines and endothelial biomarkers. Collectively, these data demonstrate that therapeutic heat stress may represent a promising strategy to protect the lung endothelium from severe reperfusion injury. [ABSTRACT FROM AUTHOR]