Effects of inflammatory cytokines on the release and cleavage of the endothelial cell-derived ultralarge von Willebrand factor multimers under flow

ADAMTS-13 Prevents VWF-Mediated Gastric Cancer Metastasis

BACKGROUND

Gastric cancer invades local tissue extensively and metastasizes through the circulation to remote organs. Patients with metastasized gastric cancer have poor clinical outcomes. The vasculature in the cancer niche is developed poorly, thus allowing cancer cells to be released into the circulation. However, it is poorly understood how cancer cells adhere to and transmigrate through the fully developed endothelium in remote organs and what key adhesive ligands are involved in the process. Here, we report results from a study designed to investigate the role of hyperadhesive VWF (von Willebrand factor) in promoting the pulmonary metastasis of gastric cancer.

METHODS

We used mouse models to investigate the roles of hyperadhesive VWF in the pulmonary metastasis of gastric cancer. The findings from these mouse models were validated through in vitro experiments that specifically examined how VWF promoted gastric cancer-derived extracellular vesicles to activate endothelial cells and analyzed established databases of patients with gastric cancer.

RESULTS

VWF in cancer-bearing mice became hyperadhesive and mediated the adhesion of gastric cancer-derived extracellular vesicles to the endothelium, where gastric cancer-derived extracellular vesicles caused endothelial permeability and promoted the transmigration of cancer cells to the interstitial tissue of the lungs. Reducing VWF adhesive activity by the metalloprotease ADAMTS-13 (A disintegrin and metalloprotease with thrombospondin type motifs, type 13) prevented the pulmonary metastasis of gastric cancer cells in mice. We further validated the findings in mice through targeted in vitro experiments and by associating VWF with the outcomes of patients with gastric cancer through established databases of patients with gastric cancer using bioinformatics tools.

CONCLUSIONS

We show how VWF becomes hyperadhesive to promote the pulmonary metastasis of gastric cancer through its interaction with gastric cancer-derived extracellular vesicles and that the hyperadhesive activity of VWF is reduced by ADAMTS-13 to prevent the metastasis.

Loss of von Willebrand factor large multimers in patients undergoing hemodialysis: A single-center, retrospective study

INTRODUCTION

Von Willebrand factor (VWF) is produced by vascular endothelial cells as large multimers and is cleaved by ADAMTS13 into an appropriate size in a shear stress-dependent manner. Excessive shear stress enhances VWF cleavage, leading to a hemorrhagic disease known as acquired von Willebrand syndrome. No clear reports on the prevalence of the loss of VWF large multimers in patients receiving hemodialysis are currently available. Therefore, this study investigated the prevalence of the loss of VWF large multimers in patients undergoing hemodialysis.

METHODS

This single-center, retrospective study involved 90 patients undergoing hemodialysis and 32 healthy participants as controls. VWF antigen levels (VWF:Ag), VWF activity (VWF:RCo), and ADAMTS13 activity were measured. VWF multimer analysis was performed by modified western blotting with an agarose gel electrophoresis, followed by densitometric evaluation of band intensities to calculate the VWF large multimer index (VWF-LMI). A VWF-LMI <80 % was defined as the loss of VWF large multimers, and the prevalence of the loss of VWF large multimers was calculated.

RESULTS

VWF:Ag and VWF:RCo levels in patients undergoing hemodialysis were significantly higher than those in healthy individuals (p < 0.01 both) and were negatively correlated with ADAMTS13 activity (p < 0.01, R = -0.353 and p < 0.01, R = -0.392, respectively). A VWF-LMI <80 % was present in 24 of 90 patients.

CONCLUSIONS

The loss of VWF large multimers was identified in 26.7 % of patients receiving hemodialysis. However, the prevalence of the loss of VWF multimers in these patients may be underestimated, as their relatively high VWF activity makes significant bleeding manifestations less likely.

Alterations in von Willebrand Factor Levels in Patients with Malaria: A Systematic Review and Meta-Analysis of Disease Severity

Background and Objectives: Elevated von Willebrand factor (vWF) levels have been reported in malaria, but their relationship with disease severity remains unclear. This study aimed to compare vWF levels between Plasmodium-infected and uninfected individuals and assess changes in severe infections. Materials and Methods: The systematic review was registered in PROSPERO (CRD42024558479). A comprehensive search across six databases identified studies reporting vWF levels in malaria. A meta-analysis was conducted using a random-effects model, with standardized mean difference (SMD) as the effect measure due to varying measurement units. Heterogeneity was assessed using the I2 statistic. Results: Of 1647 identified records, 26 studies met the inclusion criteria. The meta-analysis showed significantly higher vWF levels in Plasmodium-infected individuals compared to uninfected controls (p < 0.001, SMD: 2.689 [95% CI 1.362; 4.017], I2: 98.1%, 12 studies, 3109 participants). However, no significant difference was found between severe and less severe cases (p = 0.051, SMD: 3.551 [95% CI -0.007; 7.109], I2: 99.3%, 8 studies, 1453 participants). Conclusions: vWF levels are significantly elevated in individuals with Plasmodium infections, indicating a potential role in malaria pathophysiology. Although levels tend to be higher in severe cases, current evidence is insufficient to support vWF as a reliable marker for disease severity. Further prospective and well-controlled studies are needed to validate its diagnostic and prognostic value in malaria management.

The Course and Clinical Relevance of Interleukin-6 in Cerebrospinal Fluid in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The neuroinflammatory response to aneurysmal subarachnoid hemorrhage (SAH) might have a crucial impact on the burden of disease. We aimed to analyze the behavior of interleukin-6 (IL-6) in cerebrospinal fluid (CSF) during SAH and its relation to complications and outcomes.

METHODS

We included consecutive SAH patients with regular CSF IL-6 measurements treated between January 2005 and June 2016 (n = 420). IL-6 levels were recorded every 72 hours (from day 1-3 [d1-3] until day 19-21 [d19-21]). Study endpoints were delayed cerebral infarction (DC-infarction), in-hospital mortality, and unfavorable outcome at 6 months after SAH (modified Rankin scale >3).

RESULTS

There was an initial increase of IL-6 on d4-6 (median: 3121 vs. 1467 pg/mL on d1-3), with a gradual decrease over the remaining time. The IL-6 value on d1-3 showed associations with in-hospital mortality and unfavorable outcomes, whereas IL-6 on d4-6 was related to the risk of DC-infarction and in-hospital mortality. According to receiver operating characteristic curves, clinically relevant cutoffs were defined for IL-6 on d1-3 (>2000 pg/mL) and d4-6 (>2500 pg/mL). In multivariate analysis, IL-6 >2000 pg/mL on d1-3 was independently associated with in-hospital mortality (adjusted odds ratio [aOR = 2.67; P = 0.009) and unfavorable outcome (aOR=2.30; P = 0.006). In turn, IL-6 >2500 pg/mL on d4-6 was independently associated with in-hospital mortality (aOR = 2.28; P = 0.017) and DC-infarction (aOR = 1.64; P = 0.044). SAH individuals with angiographic vasospasm showed marked elevation of IL-6 from d1-3 to d4-6 compared to their counterparts without vasospasm (+1770.5 vs. -21 pg/mL; P = 0.02).

CONCLUSIONS

Our data confirm the substantial impact of neuroinflammation on SAH. CSF IL-6 values measured during the first week after SAH occurrence present the most valuable outcome predictors.

Imbalanced VWF-ADAMTS13 axis contributes to the detrimental impact of a preceding respiratory tract infection on stroke

ABSTRACT

Respiratory tract infections (RTIs) caused by bacteria or viruses are associated with stroke severity. Recent studies have revealed an imbalance in the von Willebrand factor (VWF)-ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs 13) axis in patients with RTIs, including coronavirus disease 2019. We examined whether this imbalance contributes to RTI-mediated stroke severity. Wild-type (WT), Vwf-/-, or Adamts13-/- mice with respective littermate controls (Vwf+/+ or Adamts13+/+) were infected intranasally with sublethal doses of Staphylococcus aureus (on days 0, 2, and 5) or mouse-adapted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; on day 0) and subjected to transient (30 or 45 minutes) cerebral ischemia followed by reperfusion. In S aureus-infected mice, infarct volumes were assessed on day 2 and functional outcomes on weeks 1 and 4 after reperfusion. In SARS-CoV-2-infected mice, infarct volumes and functional outcomes (Bederson score) were assessed on day 1 after reperfusion. We demonstrated that S aureus or SARS-CoV-2 RTI was accompanied by an imbalance in the VWF-ADAMTS13 axis and an increase in plasma levels of interleukin-6, C-X-C motif chemokine ligand 1, and monocyte chemoattractant protein-1, which was associated with larger infarcts and worse functional outcomes (P < .05 vs mock infection). S aureus- or SARS-CoV-2-infected Vwf-/- mice exhibited reduced infarcts and improved functional outcomes, whereas infected Adamts13-/- mice displayed greater stroke severity (P < .05 vs control). In the models of RTI preceding stroke, VWF contributes to stroke severity, whereas ADAMTS13 is protective.

Cardiovascular disease and thrombosis: Intersections with the immune system, inflammation, and the coagulation system

The coagulation and immune system, both essential physiological systems in the human body, are intricately interconnected and play a critical role in determining the overall health of patients. These systems collaborate via various shared regulatory pathways, such as the Tissue Factor (TF) Pathway. Immunological cells that express TF and generate pro-inflammatory cytokines have the ability to affect coagulation. Conversely, coagulation factors and processes have a reciprocal effect on immunological responses by stimulating immune cells and regulating their functions. These interconnected pathways play a role in both preserving well-being and contributing to a range of pathological disorders. The close relationship between blood clotting and inflammation in the development of vascular disease has become a central focus of clinical study. This research specifically examines the crucial elements of this interaction within the contexts of cardiovascular disease and acute coronary syndrome. Tissue factor, the primary trigger of the extrinsic coagulation pathway, has a crucial function by inducing a proinflammatory reaction through the activation of coagulation factors. This, in turn, initiates coagulation and subsequent cellular signalling pathways. Protease-activated receptors establish the molecular connection between coagulation and inflammation by interacting with activated clotting factors II, X, and VII. Thrombosis, a condition characterised by the formation of blood clots, is the most dreaded consequence of cardiovascular disorders and a leading cause of death globally. Consequently, it poses a significant challenge to healthcare systems. Antithrombotic treatments efficiently target platelets and the coagulation cascade, but they come with the inherent danger of causing bleeding. Furthermore, antithrombotics are unable to fully eliminate thrombotic events, highlighting a treatment deficiency caused by a third mechanism that has not yet been sufficiently addressed, namely inflammation. Understanding these connections may aid in the development of novel approaches to mitigate the harmful mutual exacerbation of inflammation and coagulation. Gaining a comprehensive understanding of the intricate interaction among these systems is crucial for the management of diseases and the creation of efficacious remedies. Through the examination of these prevalent regulatory systems, we can discover novel therapeutic approaches that specifically target these complex illnesses. This paper provides a thorough examination of the reciprocal relationship between the coagulation and immune systems, emphasising its importance in maintaining health and understanding disease processes. This review examines the interplay between inflammation and thrombosis and its role in the development of thrombotic disorders.

The Role of the VWF/ADAMTS13 Axis in the Thromboinflammatory Response in Ischemic Stroke After SARS-CoV2 Infection

BACKGROUND

SARS-CoV2 infections increase the risk of ischemic stroke (IS), potentially through a thromboinflammatory cascade driven by an imbalance in the ratio of Von Willebrand Factor (VWF) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), leading to the formation of ultra-large VWF (UL-VWF). However, the SARS-CoV2 infection's contribution to any VWF/ADAMTS13 axis imbalance and the subsequent thromboinflammatory response post-stroke remain poorly understood.

METHODS

We performed a detailed thromboinflammatory profile of the plasma samples from three experimental cohorts matched by age, sex, and stroke severity: non-stroke controls (n = 23), SARS-CoV2 negative IS (n = 22), and SARS-CoV2 positive IS (n = 24). SARS-CoV2 positive IS patients presented varying degrees of infection severity.

RESULTS

We observed an increase in VWF and UL-VWF and a decrease in ADAMTS13 in the SARS-CoV2 positive IS cohort, suggesting a VWF/ADAMTS13 axis imbalance. Interleukin-6 (IL-6) levels were positively correlated with VWF and negatively correlated with ADAMTS13, suggesting that IL-6 may drive this imbalance. Fibrinogen and D-Dimers were elevated in SARS-CoV2 negative IS cohort and SARS-CoV2 positive IS cohort, but D-Dimers were within the normal range, indicating no disseminated intravascular coagulation. Factor IX (FIX) was elevated in the SARS-CoV2 negative IS cohort. Tissue plasminogen activator (tPA) was elevated in the SARS-CoV2 positive IS cohort, suggesting no fibrinolysis defects. Matrix Metalloproteinase-2 (MMP-2) and soluble Intracellular Adhesion Molecule-1 (sICAM-1) were elevated in the SARS-CoV2 negative IS cohort.

CONCLUSIONS

We show that SARS-CoV2 infections drive a VWF/ADAMTS13 axis imbalance, inducing an increase in tPA while decreasing FIX, MMP-2, and sICAM-1 post-stroke.

Weibel-Palade bodies: function and role in thrombotic thrombocytopenic purpura and in diarrhea phase of STEC-hemolytic uremic syndrome

Vascular endothelial cells are equipped with numerous specialized granules called Weibel-Palade bodies (WPBs). They contain a cocktail of proteins that can be rapidly secreted (3-5 min) into the vascular lumen after an appropriate stimulus such as thrombin. These proteins are ready without synthesis. Von Willebrand factor (VWF) and P-selectin are the main constituents of WPBs. Upon stimulation, release of ultralarge VWF multimers occurs and assembles into VWF strings on the apical side of endothelium. The VWF A1 domain becomes exposed in a shear-dependent manner recruiting and activating platelets. VWF is able to recruit leukocytes via direct leukocyte binding or via the activated platelets promoting NETosis. Ultralarge VWF strings are ultimately cleaved into smaller pieces by the protease ADAMTS-13 preventing excessive platelet adhesion. Under carefully performed flowing conditions and adequate dose of Shiga toxins, the toxin induces the release of ultralarge VWF multimers from cultured endothelial cells. This basic information allows insight into the pathogenesis of thrombotic thrombocytopenic purpura (TTP) and of STEC-HUS in the diarrhea phase. In TTP, ADAMTS-13 activity is deficient and systemic aggregation of platelets will occur after a second trigger. In STEC-HUS, stimulated release of WPB components in the diarrhea phase of the disease can be presumed to be the first hit in the damage of Gb3 positive endothelial cells.

Association of primary and secondary hemostasis biomarkers with acute ischemic stroke outcome in patients undergoing thrombectomy, with or without thrombolytics: post hoc analysis of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands-NO IV

BACKGROUND

Intravenous thrombolysis (IVT) using recombinant tissue plasminogen activator prior to endovascular thrombectomy treatment (EVT) failed to improve treatment effect in acute ischemic stroke (AIS) patients compared with EVT alone.

OBJECTIVES

We investigated whether primary and secondary hemostasis biomarkers are associated with the effect of intravenous thrombolytics on clinical and radiological outcomes after EVT.

METHODS

In the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN)-NO IV, AIS patients were randomized to receive IVT plus EVT or EVT alone. We measured hemostatic biomarkers before and 24 hours postreperfusion to determine changes in biomarkers and the association of the biomarkers with short term stroke severity on National Institutes of Health Stroke Scale score, long-term functional outcome (modified Rankin scale [mRS] score), post-EVT extended Thrombolysis in Cerebral Infarction score, and final infarct size.

RESULTS

This substudy included 214 of the 539 AIS patients who underwent IVT + EVT (n = 108/266) or EVT alone (n = 106/273). In the EVT group, low soluble glycoprotein VI (sGPVI) and high factor (F)VIII levels before treatment were associated with severe National Institutes of Health Stroke Scale score at 24 hours and poor mRS score at 90 days posttreatment, respectively. Also, in this group, sGPVI levels 24 hours after treatment were negatively associated with final infarct size. In the IVT + EVT group, high fibrinogen before treatment was associated with good extended Thrombolysis in Cerebral Infarction score, and low a disintegrin and metalloprotease with thrombospondin motif repeats 13 activity 24 hours posttreatment was associated with an unfavorable mRS score at 90 days.

CONCLUSION

Our findings suggest that patients with high FVIII and fibrinogen and low sGPVI levels might be the most suitable candidates for IVT + EVT and that patients with low a disintegrin and metalloprotease with thrombospondin motif repeats 13 activity might be suitable for EVT alone.

Predictive nomogram for ischemic stroke risk in clear cell renal cell carcinoma patients

Clear cell renal cell carcinoma (ccRCC) and ischemic stroke are critical global health challenges with a notable association. This study explores the correlation between tumor-related factors and ischemic stroke risk, aiming to construct a predictive nomogram model for ischemic stroke in ccRCC patients. We retrospectively analyzed data from ccRCC patients who underwent nephrectomy at the First Hospital of Shanxi Medical University between January 1, 2013, and May 31, 2022. The data were randomly divided into a training cohort (70%) and a validation cohort (30%). Predictive factors were identified using univariate logistic regression, least absolute shrinkage and selection operator regression, and multivariate logistic regression. A nomogram and a Shiny local calculator were developed using these predictors. We identified six predictors for the nomogram: WHO/ISUP grade, diabetes, hypertension, LDL-C, age, and D-dimer. The nomogram showed good discrimination, with an area under the ROC curve of 0.816 in the training cohort and 0.775 in the validation cohort. The optimal cutoff value was 53.7%. The model demonstrated excellent calibration and clinical applicability. WHO/ISUP grade correlates with ischemic stroke risk, offering insights into cancer-related ischemic stroke mechanisms. This nomogram aids in identifying high-risk individuals among ccRCC patients, facilitating early management and improved outcomes.

Von Willebrand factor: a possible biomarker for disease activity in vasculitis

OBJECTIVE

Inflammation markers, e.g. C- reactive protein (CRP) and sedimentation rate, can be normal despite active vasculitis. Von Willebrand factor (vWF) is secreted from endothelial cells in response to vascular damage. Some reports suggest increased vWF levels in vasculitis. This study aimed to evaluate vWF serum concentration in vasculitis patients as a possible biomarker of disease activity and to review the current literature.

METHOD

Adult patients with systemic vasculitis were prospectively enrolled. Disease activity was recorded using the Birmingham Vasculitis Activity Score (BVAS) version 3. Blood group-adjusted vWF antigen serum level was evaluated at diagnosis and, when available, after treatment.

RESULTS

Twenty-five vasculitis patients were compared to 15 healthy controls. The mean age of patients was 56 ± 17 years and 56% were women. Forty percent had anti-neutrophil cytoplasmic autoantibody-associated vasculitis, 20% giant cell arteritis, 16% polyarteritis nodosa, 8% Takayasu arteritis, and the rest had other vasculitides. The mean disease duration was 3.4 ± 4.8 years. Mean vWF was higher in patients with active vasculitis than in healthy controls (212 ± 81% vs 106 ± 26%, p < 0.001). vWF levels directly correlated with BVAS. In 13 patients with active vasculitis who reached remission or low disease activity after treatment, vWF level at follow-up decreased significantly. In three out of five patients who were treated with interleukin-6 inhibitors, vWF was elevated despite normal CRP levels, while vasculitis was clinically active.

CONCLUSION

vWF antigen serum level is increased in active vasculitis and could potentially serve as a biomarker for active disease.

Imbalance in the vWF - ADAMTS13 axis exists early in acute pancreatitis and predicts persistent organ failure and pancreatic necrosis-a prospective study

BACKGROUND

The pathophysiology of Acute Pancreatitis (AP) may be complicated by endothelial activation. von Willebrand Factor (vWF)- ADAMTS13 axis is a marker of endothelial activation. The study aimed to investigate the axis in AP, comparing it in patients with and without persistent organ failure (OF), with and without pancreatic necrosis, and correlating it with the standard severity scores (CRP, APACHE II, BISAP, SOFA, and qSOFA) METHODS: vWF-Antigen (vWF:Ag), vWF-Collagen-Binding-Assay (vWF:CBA), and ADAMTS13 activity (ADAMTS13:act) levels were measured within 5 days of symptom onset in consecutive patients (n = 98), who were admitted with a first episode of AP (Dec 2021-May 2023).

RESULTS

Of the 98 patients admitted with AP, 78(79.6 %) had no or transient OF; 20(20.4 %) had persistent OF. Age was comparable (43.73 ± 15.36 vs 38.65 ± 13.69) [mean ± SD](years), and males were predominant in both groups (70.5 % vs 80 %). Patientswith persistent OF had higher vWF:CBA(%)[323(279-486.5) vs 199.5(159.1-295.75)] and lower ADAMTS13:act(%)[35.4(23.8-56.85) vs 56.35(44.1-71.9)][median (25th - 75th percentile)](P = 0.001) than those with no or transient OF. Patients with pancreatic necrosis (n = 19) had lower ADAMTS13:act(%)[42.79 ± 18.69] than those without pancreatic necrosis (n = 18) [62.49 ± 22.64] (P < 0.01). ADAMTS13:act had a negative correlation(r = -0.2), whereas vWF:Ag and vWF:CBA had a positive correlation (r = 0.2) with the standard severity scores (P < 0.05). ADAMTS13:act could predict pancreatic necrosis [AUROC-0.737, P < 0.05] and persistent OF [AUROC-0.746, P < 0.001], while vWF:CBA could predict persistent OF [AUROC- 0.73, P < 0.001].

CONCLUSION

vWF-ADAMTS13 axis helps to predict severe disease and is associated with poor outcomes in acute pancreatitis.

The Contribution of Neutrophil Extracellular Traps to Coagulopathy in Patients with COVID-19-Related Thrombosis

COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with hypercoagulability and increased incidence of thrombotic events. In this study, we investigated the levels of neutrophil extracellular trap biomarkers and von Willebrand factor to assess if these could predict the occurrence of a thrombotic event in COVID-19 patients. We enrolled 202 patients hospitalized with symptomatic COVID-19 infection. Of those, 104 patients did not experience any type of thrombotic events before or during their hospitalization. These patients were compared to the other cohort of 98, who experienced thrombotic events before or during their hospitalization. In total, 61 patients who experienced thrombotic events had the event after initial blood collection, so the predictive capacity of biomarkers in these patients was evaluated. Citrullinated histone H3 was the best predictive biomarker for thrombotic events in COVID-19 regardless of age, sex, and race; disease severity was also a significant predictor in most thrombotic event groups. These results may better inform treatment and prophylaxis of thrombotic events in COVID-19 and similar viral illnesses in the future to improve outcomes and reduce mortality.

Clinical Utility of Recently Food and Drug Administration-Approved IntelliSep Test (Sepsis Biomarker) for Early Diagnosis of Sepsis: Comparison with Other Biomarkers

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.

Coagulation abnormalities associated with CAR-T-cell therapy in haematological malignancies: A review

Chimeric antigen receptor (CAR)-T-cell therapy has demonstrated considerable efficacy and safety in the treatment of patients with relapsed/refractory haematological malignancies. Owing to significant advances, CAR-T-cell therapeutic modality has undergone substantial shifts in its clinical application. Coagulation abnormalities, which are prevalent complications in CAR-T-cell therapy, can range in severity from simple abnormalities in coagulation parameters to serious haemorrhage or disseminated intravascular coagulation associated with life-threatening multiorgan dysfunction. Nonetheless, there is a lack of a comprehensive overview concerning the coagulation abnormalities associated with CAR-T-cell therapy. With an aim to attract heightened clinical focus and to enhance the safety of CAR-T-cell therapy, this review presents the characteristics of the coagulation abnormalities associated with CAR-T-cell therapy, including clinical manifestations, coagulation parameters, pathogenesis, risk factors and their influence on treatment efficacy in patients receiving CAR-T-cell infusion. Due to limited data, these conclusions may undergo changes as more experience accumulates.

Selecting potential biomarkers of plasma proteins in mares with endometritis

BACKGROUND

Endometritis is a common condition in mares that causes significant economic loss. Lacking obvious clinical signs, the clinical diagnosis of endometritis in mares relies on case-by-case clinical examinations, which can be particularly inefficient in large-scale farms. Therefore, the identification of potential biomarkers can serve as a non-invasive and efficient screening technique for endometritis in mares.

OBJECTIVES

To compare the blood proteome between fertile mares and mares with endometritis to identify biomarkers potentially associated with the development of endometritis and validate their predictive potential.

STUDY DESIGN

Observational and experimental study.

METHODS

Differentially expressed proteins were identified via Data Independent Acquisition (DIA) proteomic profiling in a screening cohort composed of eight healthy mares and eight mares with endometritis. Subsequently, enzyme-linked immunosorbent assay was employed that included a validation cohort of 40 healthy mares and 40 mares with endometritis to verify the accuracy and sensitivity of the identified proteins, thereby establishing a diagnostic threshold.

RESULTS

In the screening cohort, 12 proteins were significantly differentially expressed between endometritis mares and healthy controls (p < 0.05, outside the 1/1.2 to 1.2-fold). In the validation experiment, all six screened proteins were assessed with area under the curve (AUC) >0.8.

MAIN LIMITATIONS

The samples displayed certain levels of individual heterogeneity, and the number of samples analysed was limited. Additionally, the identified biomarkers were primarily associated with generalised inflammation, which potentially limited their specificity for endometritis.

CONCLUSION

Levels of plasma proteins are sensitive indicators of equine endometritis and potential tools for endometritis screening. In plasma, fetuin B, von Willebrand factor, vitamin K-dependent protein C, insulin-like growth factor binding protein 3, interleukin 1 receptor accessory protein, and type II cell cytoskeleton showed great predictive ability, with fetuin B being the best predictor (AUC = 0.93, 95% CI: 0.89-0.98), which performs better when combined with all six detected proteins (AUC = 1, 95% CI: 0.99-1.00).

The critical role of endothelial cell in the toxicity associated with chimeric antigen receptor T cell therapy and intervention strategies

Chimeric antigen receptor (CAR)-T cell therapy has shown promising results in patients with hematological malignancies. However, many patients still have poor prognoses or even fatal outcomes due to the life-threatening toxicities associated with the therapy. Moreover, even after improving the known influencing factors (such as number or type of CAR-T infusion) related to CAR-T cell infusion, the results remain unsatisfactory. In recent years, it has been found that endothelial cells (ECs), which are key components of the organization, play a crucial role in various aspects of immune system activation and inflammatory response. The levels of typical markers of endothelial activation positively correlated with the severity of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxic syndrome (ICANS), suggesting that ECs are important targets for intervention and toxicity prevention. This review focuses on the critical role of ECs in CRS and ICANS and the intervention strategies adopted.

Oxidative Stress, Endothelial Dysfunction, and N-Acetylcysteine in Type 2 Diabetes Mellitus

Significance: Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality globally. Endothelial dysfunction is closely associated with the development and progression of CVDs. Patients with diabetes mellitus (DM) especially type 2 DM (T2DM) exhibit a significant endothelial cell (EC) dysfunction with substantially increased risk for CVDs. Recent Advances: Excessive reactive oxygen species (ROS) and oxidative stress are important contributing factors to EC dysfunction and subsequent CVDs. ROS production is significantly increased in DM and is critically involved in the development of endothelial dysfunction in diabetic patients. In this review, efforts are made to discuss the role of excessive ROS and oxidative stress in the pathogenesis of endothelial dysfunction and the mechanisms for excessive ROS production and oxidative stress in T2DM. Critical Issues: Although studies with diabetic animal models have shown that targeting ROS with traditional antioxidant vitamins C and E or other antioxidant supplements provides promising beneficial effects on endothelial function, the cardiovascular outcomes of clinical studies with these antioxidant supplements have been inconsistent in diabetic patients. Future Directions: Preclinical and limited clinical data suggest that N-acetylcysteine (NAC) treatment may improve endothelial function in diabetic patients. However, well-designed clinical studies are needed to determine if NAC supplementation would effectively preserve endothelial function and improve the clinical outcomes of diabetic patients with reduced cardiovascular morbidity and mortality. With better understanding on the mechanisms of ROS generation and ROS-mediated endothelial damages/dysfunction, it is anticipated that new selective ROS-modulating agents and effective personalized strategies will be developed for the management of endothelial dysfunction in DM.

Treatment of cytokine release syndrome-induced vascular endothelial injury using mesenchymal stem cells

Cytokine release syndrome (CRS) is an acute systemic inflammatory reaction in which hyperactivated immune cells suddenly release a large amount of cytokines, leading to exaggerated inflammatory responses, multiple organ dysfunction, and even death. Although palliative treatment strategies have significantly reduced the overall mortality, novel targeted treatment regimens with superior therapy efficacy are urgently needed. Vascular endothelial cells (ECs) are important target cells of systemic inflammation, and their destruction is considered to be the initiating event underlying many serious complications of CRS. Mesenchymal stem/stromal cells (MSCs) are multipotent cells with self-renewing differentiation capacity and immunomodulatory properties. MSC transplantation can effectively suppress the activation of immune cells, reduce the bulk release of cytokines, and repair damaged tissues and organs. Here, we review the molecular mechanisms underlying CRS-induced vascular endothelial injury and discuss potential treatments using MSCs. Preclinical studies demonstrate that MSC therapy can effectively repair endothelium damage and thus reduce the incidence and severity of ensuing CRS-induced complications. This review highlights the therapeutic role of MSCs in fighting against CRS-induced EC damage, and summarizes the possible therapeutic formulations of MSCs for improved efficacy in future clinical trials.

The Interplay between Liver Sinusoidal Endothelial Cells, Platelets, and Neutrophil Extracellular Traps in the Development and Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a societal burden due to the lack of effective treatment and incomplete pathophysiology understanding. This review explores the intricate connections among liver sinusoidal endothelial cells (LSECs), platelets, neutrophil extracellular traps (NETs), and coagulation disruptions in MASLD pathogenesis. In MASLD's early stages, LSECs undergo capillarization and dysfunction due to excessive dietary macronutrients and gut-derived products. Capillarization leads to ischemic changes in hepatocytes, triggering pro-inflammatory responses in Kupffer cells (KCs) and activating hepatic stellate cells (HSCs). Capillarized LSECs show a pro-inflammatory phenotype through adhesion molecule overexpression, autophagy loss, and increased cytokines production. Platelet interaction favors leucocyte recruitment, NETs formation, and liver inflammatory foci. Liver fibrosis is facilitated by reduced nitric oxide, HSC activation, profibrogenic mediators, and increased angiogenesis. Moreover, platelet attachment, activation, α-granule cargo release, and NETs formation contribute to MASLD progression. Platelets foster fibrosis and microthrombosis, leading to parenchymal extinction and fibrotic healing. Additionally, platelets promote tumor growth, epithelial-mesenchymal transition, and tumor cell metastasis. MASLD's prothrombotic features are exacerbated by insulin resistance, diabetes, and obesity, manifesting as increased von Willebrand factor, platelet hyperaggregability, hypo-fibrinolysis, and a prothrombotic fibrin clot structure. Improving LSEC health and using antiplatelet treatment appear promising for preventing MASLD development and progression.

Exploring the role of bacterial virulence factors and host elements in septic arthritis: insights from animal models for innovative therapies

Septic arthritis, characterized as one of the most aggressive joint diseases, is primarily attributed to Staphylococcus aureus (S. aureus) and often results from hematogenous dissemination. Even with prompt treatment, septic arthritis frequently inflicts irreversible joint damage, leading to sustained joint dysfunction in a significant proportion of patients. Despite the unsatisfactory outcomes, current therapeutic approaches for septic arthritis have remained stagnant for decades. In the clinical context, devising innovative strategies to mitigate joint damage necessitates a profound comprehension of the pivotal disease mechanisms. This entails unraveling how bacterial virulence factors interact with host elements to facilitate bacterial invasion into the joint and identifying the principal drivers of joint damage. Leveraging animal models of septic arthritis emerges as a potent tool to achieve these objectives. This review provides a comprehensive overview of the historical evolution and recent advancements in septic arthritis models. Additionally, we address practical considerations regarding experimental protocols. Furthermore, we delve into the utility of these animal models, such as their contribution to the discovery of novel bacterial virulence factors and host elements that play pivotal roles in the initiation and progression of septic arthritis. Finally, we summarize the latest developments in novel therapeutic strategies against septic arthritis, leveraging insights gained from these unique animal models.

REVIEWING THE DYSREGULATION OF ADAMTS13 AND VWF IN SEPSIS

ABSTRACT

Sepsis is defined as a life-threatening organ dysfunction caused by excessive host response to infection, and represents the most common cause of in-hospital deaths. Sepsis accounts for 30% of all critically ill patients in the intensive care unit (ICU), and has a global mortality rate of 20%. Activation of blood coagulation during sepsis and septic shock can lead to disseminated intravascular coagulation, which is characterized by microvascular thrombosis. Von Willebrand factor (VWF) and ADAMTS13 are two important regulators of blood coagulation that may be important links between sepsis and mortality in the ICU. Herein we review our current understanding of VWF and ADAMTS13 in sepsis and other critical illnesses and discuss their contribution to disease pathophysiology, their use as markers of severe illness, and potential targets for new therapeutic development.

Alterations in the von Willebrand factor/ADAMTS-13 axis in preeclampsia

BACKGROUND

Preeclampsia is a gestational hypertensive disorder characterized by maternal endothelial activation and increased ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) inhibitor to placental growth factor (PlGF). The von Willebrand factor (VWF)/ADAMTS-13 axis is of interest because of the underlying endothelial activation and clinical overlap with pregnancy-associated thrombotic thrombocytopenic purpura.

OBJECTIVES

To assess VWF, ADAMTS-13, and VWF/ADAMTS-13 ratio in preeclampsia and look for associations with sFlt-1/PlGF ratio and clinical features.

METHODS

Thirty-four preeclampsia cases and 48 normal pregnancies were assessed in a case-control study. Twelve normal pregnancies in women with a history of preeclampsia formed an additional comparator group. VWF antigen (VWF:Ag) and VWF activity (VWF:Ac [VWF:glycoprotein IbM]) were measured via automated immunoturbidimetric assay, ADAMTS-13 activity was measured via fluorescence resonance energy transfer-VWF73 assay, and sFlt-1 and PlGF were measured via enzyme-linked immunosorbent assay.

RESULTS

VWF:Ag was higher in preeclampsia than in normal pregnancy (median, 3.07 vs 1.87 IU/mL; P < .0001). ADAMTS-13 activity was slightly lower (median, 89.6 vs 94.4 IU/dL; P = .02), with no severe deficiencies. Significant elevations in VWF:Ac were not observed in preeclampsia, resulting in reduced VWF:Ac/VWF:Ag ratios (median, 0.77 vs 0.97; P < .0001). VWF:Ag/ADAMTS-13 ratios were significantly higher in preeclampsia (median, 3.42 vs 2.06; P < .0001), with an adjusted odds ratio of 19.2 for a ratio of >2.7 (>75th centile of normal pregnancy). Those with a history of preeclampsia had similar ratios to normal pregnant controls. VWF:Ag/ADAMTS-13 and sFlt-1/PlGF were not correlated. However, percentage reduction in platelets correlated positively with VWF:Ac (P = .01), VWF:Ac/VWF:Ag ratio (P = .004), and sFlt-1/PlGF ratio (P = .01).

CONCLUSION

The VWF/ADAMTS-13 axis is significantly altered in preeclampsia. Further investigation of potential clinical utility is warranted.

Searching for New Biomarkers to Assess COVID-19 Patients: A Pilot Study

During the initial diagnosis of urgent medical conditions, which include acute infectious diseases, it is important to assess the severity of the patient's clinical state as quickly as possible. Unlike individual biochemical or physiological indicators, derived indices make it possible to better characterize a complex syndrome as a set of symptoms, and therefore quickly take a set of adequate measures. Recently, we reported on novel diagnostic indices containing butyrylcholinesterase (BChE) activity, which is decreased in COVID-19 patients. Also, in these patients, the secretion of von Willebrand factor (vWF) increases, which leads to thrombosis in the microvascular bed. The objective of this study was the determination of the concentration and activity of vWF in patients with COVID-19, and the search for new diagnostic indices. One of the main objectives was to compare the prognostic values of some individual and newly derived indices. Patients with COVID-19 were retrospectively divided into two groups: survivors (n = 77) and deceased (n = 24). According to clinical symptoms and computed tomography (CT) results, the course of disease was predominantly moderate in severity. The first blood sample (first point) was taken upon admission to the hospital, the second sample (second point)-within 4-6 days after admission. Along with the standard spectrum of biochemical indicators, BChE activity (BChEa or BChEb for acetylthiocholin or butyrylthiocholin, respectively), malondialdehyde (MDA), and vWF analysis (its antigen level, AGFW, and its activity, ActWF) were determined and new diagnostic indices were derived. The pooled sensitivity, specificity, and area under the receiver operating curve (AUC), as well as Likelihood ratio (LR) and Odds ratio (OR) were calculated. The level of vWF antigen in the deceased group was 1.5-fold higher than the level in the group of survivors. Indices that include vWF antigen levels are superior to indices using vWF activity. It was found that the index [Urea] × [AGWF] × 1000/(BChEb × [ALB]) had the best discriminatory power to predict COVID-19 mortality (AUC = 0.91 [0.83, 1.00], p < 0.0001; OR = 72.0 [7.5, 689], p = 0.0002). In addition, [Urea] × 1000/(BChEb × [ALB]) was a good predictor of mortality (AUC = 0.95 [0.89, 1.00], p < 0.0001; OR = 31.5 [3.4, 293], p = 0.0024). The index [Urea] × [AGWF] × 1000/(BChEb × [ALB]) was the best predictor of mortality associated with COVID-19 infection, followed by [Urea] × 1000/(BChEb × [ALB]). After validation in a subsequent cohort, these two indices could be recommended for diagnostic laboratories.

Dynamic and functional linkage between von Willebrand factor and ADAMTS-13 with aging: an Atherosclerosis Risk in Community study

BACKGROUND

von Willebrand factor (VWF) is a multimeric glycoprotein critically involved in hemostasis, thrombosis, and inflammation. VWF function is regulated by its antigen levels, multimeric structures, and the state of enzymatic cleavage. Population studies in the past have focused almost exclusively on VWF antigen levels in cross-sectional study designs.

OBJECTIVE

To identify subjects in the Atherosclerosis Risk in Community study who had persistently low and high VWF antigen over 10 years and to quantify longitudinal changes in the biological activities and cleavage of VWF in these subjects.

METHODS

We measured VWF antigen, propeptide, adhesive activities, and cleavage by ADAMTS-13 quantified using a mass spectrometry method that detected the cleaved VWF peptide EQAPNLVY, as well as coagulation factor VIII activity.

RESULTS

We determined the mean subject-specific increase in VWF to be 22.0 International Units (IU)/dL over 10 years, with 95% between -0.3 and 59.7 IU/dL. This aging-related increase was also detected in VWF propeptide levels, ristocetin cofactor activity, and VWF binding to collagen. We identified 4.1% and 25.0% of subjects as having persistently low (<50 IU/dL) and high (>200 IU/dL) VWF antigen, respectively. Subjects with persistently low VWF had enhanced ristocetin cofactor activity, whereas those with persistently high VWF had elevated levels of ADAMTS-13, resulting in a comparable rate of VWF cleavage between the 2 groups.

CONCLUSIONS

These results provide new information about the effects of aging on VWF antigens and adhesive activity and identify a functional coordination between VWF and the rate of its cleavage by ADAMTS-13.

Regulation of von Willebrand factor by ADAMTS13 ameliorates lipopolysaccharide-induced lung injury in mice

The relationship between von Willebrand factor (VWF) and inflammation has attracted considerable attention in recent years. VWF, which is stored in the Weibel-Palade bodies (WPBs) of endothelial cells (ECs), is released from WPBs in response to inflammatory stimuli and is thought to contribute to inflammation by promoting leukocyte extravasation. In this study, lung injury model mice were produced by intratracheal injection with lipopolysaccharides. The severity of lung inflammation was evaluated in mice with different genotypes (wild-type, Vwf-/-, Adamts13-/-) and mice treated with drugs that inhibit VWF function. Lung inflammation was significantly ameliorated in Vwf-/- mice compared with wild-type mice. Furthermore, inflammation was significantly suppressed in wild-type mice treated with anti-VWF A1 antibody or recombinant human ADAMTS13 compared with the untreated control group. The underlying mechanism appears to be an increased VWF/ADAMTS13 ratio at the site of inflammation and the interaction between blood cell components, such as leukocytes and platelets, and the VWF A1 domain, which promotes leukocyte infiltration into the lung. This study suggested that ADAMTS13 protein and other VWF-targeting agents may be a novel therapeutic option for treatment of pulmonary inflammatory diseases.

VWF-ADAMTS13 axis dysfunction in children with sickle cell disease treated with hydroxycarbamide vs blood transfusion

Previous studies have reported elevated von Willebrand factor (VWF) levels in patients with sickle cell disease (SCD) and demonstrated a key role for the VWF-ADAMTS13 axis in the pathobiology of SCD vaso-occlusion. Although blood transfusion is the gold standard for stroke prevention in SCD, the biological mechanisms underpinning its improved efficacy compared with hydroxycarbamide are not fully understood. We hypothesized that the improved efficacy of blood transfusion might relate to differences in VWF-ADAMTS13 axis dysfunction. In total, 180 children with a confirmed diagnosis of SCD (hemoglobin SS) on hydroxycarbamide (n = 96) or blood transfusion (n = 84) were included. Despite disease-modifying treatment, plasma VWF and VWF propeptide were elevated in a significant proportion of children with SCD (33% and 47%, respectively). Crucially, all VWF parameters were significantly higher in the hydroxycarbamide compared with the blood transfusion cohort (P < .05). Additionally, increased levels of other Weibel-Palade body-stored proteins, including factor VIII (FVIII), angiopoietin-2, and osteoprotegerin were observed, indicated ongoing endothelial cell activation. Children treated with hydroxycarbamide also had higher FVIII activity and enhanced thrombin generation compared with those in the blood transfusion cohort (P < .001). Finally, hemolysis markers strongly correlated with VWF levels (P < .001) and were significantly reduced in the blood transfusion cohort (P < .001). Cumulatively, to our knowledge, our findings demonstrate for the first time that despite treatment, ongoing dysfunction of the VWF-ADAMTS13 axis is present in a significant subgroup of pediatric patients with SCD, especially those treated with hydroxycarbamide.

Platelet factor 4 limits neutrophil extracellular trap- and cell-free DNA-induced thrombogenicity and endothelial injury

Plasma cell-free DNA (cfDNA), a marker of disease severity in sepsis, is a recognized driver of thromboinflammation and a potential therapeutic target. In sepsis, plasma cfDNA is mostly derived from neutrophil extracellular trap (NET) degradation. Proposed NET-directed therapeutic strategies include preventing NET formation or accelerating NET degradation. However, NET digestion liberates pathogens and releases cfDNA that promote thrombosis and endothelial cell injury. We propose an alternative strategy of cfDNA and NET stabilization with chemokine platelet factor 4 (PF4, CXCL4). We previously showed that human PF4 (hPF4) enhances NET-mediated microbial entrapment. We now show that hPF4 interferes with thrombogenicity of cfDNA and NETs by preventing their cleavage to short-fragment and single-stranded cfDNA that more effectively activates the contact pathway of coagulation. In vitro, hPF4 also inhibits cfDNA-induced endothelial tissue factor surface expression and von Willebrand factor release. In vivo, hPF4 expression reduced plasma thrombin-antithrombin (TAT) levels in animals infused with exogenous cfDNA. Following lipopolysaccharide challenge, Cxcl4-/- mice had significant elevation in plasma TAT, cfDNA, and cystatin C levels, effects prevented by hPF4 infusion. These results show that hPF4 interacts with cfDNA and NETs to limit thrombosis and endothelial injury, an observation of potential clinical benefit in the treatment of sepsis.

Dynamic Assessment of Plasma von Willebrand Factor and ADAMTS13 Predicts Mortality in Hospitalized Patients with SARS-CoV-2 Infection

BACKGROUND

Plasma levels of von Willebrand factor (VWF) are significantly elevated in patients with coronavirus disease 2019 (COVID-19). However, dynamic changes and prognostic value of this biomarker in hospitalized patients with COVID-19 have not been determined.

METHODS

A total of 124 patients infected with SARS-CoV-2 were prospectively recruited for the study. Serial blood samples were obtained at the time of admission (D1), 3-4 days following standard-care treatments (D2), and 1-2 days prior to discharge or any time collected prior to death (D3). Plasma VWF antigen, ADAMTS13 antigen, and ADAMTS13 proteolytic activity, as well as the ratio of VWF/ADAMTS13 were determined, followed by various statistical analyses.

RESULTS

On admission, plasma levels of VWF in COVID-19 patients were significantly elevated compared with those in the healthy controls, but no statistical significance was detected among patients with different disease severity. Plasma ADAMTS13 activity but not its antigen levels were significantly lower in patients with severe or critical COVID-19 compared with that in other patient groups. Interestingly, the ratios of plasma VWF antigen to ADAMTS13 antigen were significantly higher in patients with severe or critical COVID-19 than in those with mild to moderate disease. More importantly, plasma levels of VWF and the ratios of VWF/ADAMTS13 were persistently elevated in patients with COVID-19 throughout hospitalization. Kaplan-Meier and Cox proportional hazard regression analyses demonstrated that an increased plasma level of VWF or ratio of VWF/ADAMTS13 at D2 and D3 was associated with an increased mortality rate.

CONCLUSIONS

Persistent endotheliopathy, marked by the elevated levels of plasma VWF or VWF/ADAMTS13 ratio, is present in all hospitalized patients following SARS-CoV-2 infection, which is strongly associated with mortality.

Complete spectrum of adverse events associated with chimeric antigen receptor (CAR)-T cell therapies

Chimeric antigen receptor (CAR)-T cell therapies have been approved by FDA to treat relapsed or refractory hematological malignancies. However, the adverse effects of CAR-T cell therapies are complex and can be challenging to diagnose and treat. In this review, we summarize the major adverse events, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and CAR T-cell associated HLH (carHLH), and discuss their pathophysiology, symptoms, grading, and diagnosis systems, as well as management. In a future outlook, we also provide an overview of measures and modifications to CAR-T cells that are currently being explored to limit toxicity.

A Global Assessment of Coagulation Profile and a Novel Insight into Adamts-13 Implication in Neonatal Sepsis

Neonatal sepsis is a life-threatening condition associated with significant morbidity and mortality. Sepsis-induced coagulopathy is a well-recognized entity, signifying the strong cross-talk between inflammation and coagulation. The aim of the present study was to compare the coagulation profile between the acute phase of sepsis and recovery in term and preterm neonates. Additional comparisons to healthy neonates were undertaken. Levels of clotting, anti-clotting factors and ADAMTS-13 (A disintegrin and metalloprotease with thrombospondin type-1 motives), the cleaving protein of von Willebrand factor (VWF), were measured in 16 term and preterm neonates in the acute phase of infection and following recovery, as well as in 18 healthy neonates. Clotting times were prolonged, while levels of particular clotting factors were lower in the acute phase of infection compared to controls and recovery. On the other hand, levels of fibrinogen, factor VIII (FVIII) and VWF were significantly higher in the acute phase in comparison to controls and recovery, while they remained persistently higher in the infection group compared to controls. In regard to the anticlotting mechanism, a clear suppression was observed in septic neonates. ADAMTS-13 levels were significantly lower in the acute phase of infection in comparison to controls and recovery (p = 0.015 and 0.004, respectively), while a trend toward superimposed normalization was demonstrated post infection, as higher ADAMTS-13 levels were measured in recovered neonates compared to controls (p = 0.002). The coagulation profile is considerably deranged in neonatal sepsis. ADAMTS-13 deficiency in septic neonates is a novel finding with promising future implications, as ADAMTS-13 substitution may serve as a useful therapeutic option in neonatal sepsis, prompting further investigation in future studies.

Inflammatory Mechanisms in a Neurovascular Disease: Cerebral Cavernous Malformation

Cerebral cavernous malformation (CCM) is a common cerebrovascular malformation causing intracranial hemorrhage, seizures, and focal neurologic deficits. A unique CCM lesional inflammatory microenvironment has been shown to influence the clinical course of the disease. This review addresses the inflammatory cell infiltrate in the CCM lesion and the role of a defined antigen-driven immune response in pathogenicity. We summarize immune mechanisms associated with the loss of the CCM gene and disease progression, including the potential role of immunothrombosis. We also review evidence of circulating inflammatory biomarkers associated with CCM disease and its clinical activity. We articulate future directions for this research, including the role of individual cell type contributions to the immune response in CCM, single cell transcriptomics of inflammatory cells, biomarker development, and therapeutic implications. The concepts are applicable for developing diagnostic and treatment strategies for CCM and for studying other neurovascular diseases.

A novel von Willebrand factor multimer ratio as marker of disease activity in thrombotic thrombocytopenic purpura

Immune-mediated thrombotic thrombocytopenic purpura (iTTP), an autoantibody-mediated severe ADAMTS13 deficiency, is caused by insufficient proteolytic processing of von Willebrand factor (VWF) multimers (MMs) and microvascular thrombi. Recurrence of acute iTTP is associated with persistence or reappearance of ADAMTS13 deficiency. Some patients remain in remission despite recurring or persisting severe ADAMTS13 deficiency. In a prospective 2-year observational study, we investigated VWF MM patterns and ADAMTS13 in patients with iTTP in remission and at acute episodes. Of the 83 patients with iTTP, 16 suffered 22 acute episodes whereas 67 remained in clinical remission during follow-up, including 13 with ADAMTS13 <10% and 54 with ADAMTS13 ≥10%. High -molecular weight to low-molecular weight VWF MM ratio based on sodium dodecyl sulfate-agarose gel electrophoresis was compared with ADAMTS13 activity. VWF MM ratio was significantly higher in patients in remission with <10% compared with ≥10% ADAMTS13 activity. Fourteen samples obtained from 13 to 50 days (interquartile range; median, 39) before acute iTTP onset (ADAMTS13 <10% in 9 patients and 10%-26% in 5) showed VWF MM ratios significantly higher than those from 13 patients remaining in remission with ADAMTS13 <10%. At acute iTTP onset, VWF MM ratio decreased significantly and was low in all patients despite <10% ADAMTS13. The VWF MM ratio does not depend exclusively on ADAMTS13 activity. The disappearance of high molecular weight VWF MMs resulting in low VWF MM ratio at iTTP onset may be explained by consumption of larger VWF MMs in the microcirculation. The very high VWF MM ratio preceding acute iTTP recurrence suggests that VWF processing is hampered more than in patients remaining in remission.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

Insight into increased risk of portal vein thrombosis in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the leading chronic liver diseases with increased morbidity and mortality rates for extrahepatic diseases (including cardiovascular disease, portal vein thrombosis, etc.). There is an increased risk of thrombosis in both the portal and systemic circulation in patients with NAFLD, independent of traditional liver cirrhosis. However, increased portal pressure, the most critical factor, is frequently observed in NAFLD patients, predisposing them to portal vein thrombosis (PVT). It has been reported that there is an 8.5% incidence of PVT among patients with non-cirrhotic NAFLD in a prospective cohort study. Based on the prothrombotic status of NAFLD itself, patients combined with cirrhosis may accelerate the development of PVT and lead to a poor prognosis. Moreover, PVT has been shown to complicate the procedure and adversely affect the outcome during liver transplantation surgery. NAFLD is in a prothrombotic state, and its underlying mechanisms have not been fully understood so far. Particularly noteworthy is that gastroenterologists currently overlook the higher risk of PVT in NAFLD. We investigate the pathogenesis of NAFLD complicated with PVT from the perspective of primary, secondary, and tertiary hemostasis, and also summarize relevant studies in humans. Some treatment options that may affect NAFLD and its PVT are also explored to improve patient-oriented outcomes.

Recombinant ADAMTS-13 Improves Survival of Mice Subjected to Endotoxemia

When stimulated by proinflammatory mediators, endothelial cells release ultra-large von Willebrand factor (ULVWF) multimers that are hyperactive in activating and aggregating platelets. These ULVWF multimers can accumulate in the circulation and on the inflamed endothelium because they are insufficiently cleaved by the metalloprotease ADAMTS-13, which becomes moderately deficient under conditions of systemic inflammation. This moderate ADAMTS-13 deficiency may lead to thrombotic complications that contribute to ischemic tissue injury and organ failure that are associated with severe infections. To test this hypothesis, we investigated whether recombinant ADAMTS-13 improves the pathological course of endotoxemia in lipopolysaccharide (LPS)-treated mice. C57BL/J6 mice received a bolus infusion of either 5 µg/mouse of ADAMTS-13 or vehicle control 30 min after LPS challenge and were monitored for seven-day survival. During the monitoring period, platelet counts, VWF antigen, and ADAMTS-13 activity were measured. Thrombosis was also examined by the immunohistochemistry in the liver. We found that ADAMTS-13 reduced mortality from 66% to 34.9%. The improved survival was associated with a greater recovery from thrombocytopenia, higher plasma ADAMTS-13 activity, and less thrombotic vascular occlusion. These results suggest that systemic inflammation could result in deficient ULVWF proteolysis by ADAMTS-13 and that ADAMTS-13 improves the outcomes of endotoxemia-induced inflammation.

Biomarkers of endothelial activation and inflammation in dogs with organ dysfunction secondary to sepsis

Introduction

Alteration in endothelial function during sepsis is thought to play a key role in the progression of organ failure. We herein compared plasma concentrations of endothelial activation biomarkers vascular endothelial growth factor (VEGF), hyaluronan (HA), plasminogen activator inhibitor-1 (PAI-1) and von Willebrand factor (vWF), as well as inflammatory mediator concentrations (IL-6, IL-8, IL-10, C-reactive protein and monocyte chemoattractant protein-1) in dogs with sepsis to healthy dogs.

Methods

This study was a multicenter observational clinical trial conducted at two university teaching hospitals from February 2016 until July 2017. The study included 18 client-owned dogs hospitalized with sepsis and at least one distant organ dysfunction, as well as 20 healthy dogs. Plasma biomarker concentrations were measured using ELISA. Severity of illness in dogs with sepsis was calculated using the 5-variable acute physiologic and laboratory evaluation (APPLEFAST) score. Biomarker concentrations were compared between septic and healthy dogs using linear models.

Results

Septic peritonitis was the most frequent source of sepsis (11/18; 61%), followed by pneumonia (4/18; 22%). Ten dogs (56%) had only 1 organ dysfunction, whereas 3 dogs (17%) had 2, 3 (17%) had 3, 1 (6%) had 4 and 1 (6%) had 5 organ dysfunctions. The median APPLEFAST score in the septic dogs was 28.5 (Q1-Q3, 24-31). Mean plasma concentrations of all endothelial and inflammatory biomarkers, except vWF, were higher in the sepsis cohort than in controls. The mean endothelial biomarker concentrations in the septic cohort ranged from ~2.7-fold higher for HA (difference in means; 118.2 ng/mL, 95% credible limit; 44.5-221.7) to ~150-fold for VEGF (difference in means; 76.6 pg./mL, 95% credible limit; 33.0-143.4), compared to the healthy cohort. Fifteen dogs with sepsis (83%) died; 7 (46%) were euthanized and 8 (53%) died during hospitalization.

Conclusion

Dogs with naturally occurring sepsis and organ dysfunction had higher mean concentrations of biomarkers of endothelial activation and inflammation compared to healthy dogs, broadening our understanding of the pathophysiology of sepsis secondary to endothelial dysfunction.

Microvascular Thrombosis and Liver Fibrosis Progression: Mechanisms and Clinical Applications

Fibrosis is an unavoidable consequence of chronic inflammation. Extracellular matrix deposition by fibroblasts, stimulated by multiple pathways, is the first step in the onset of chronic liver disease, and its propagation promotes liver dysfunction. At the same time, chronic liver disease is characterized by alterations in primary and secondary hemostasis but unlike previously thought, these changes are not associated with an increased risk of bleeding complications. In recent years, the role of coagulation imbalance has been postulated as one of the main mechanisms promoting hepatic fibrogenesis. In this review, we aim to investigate the function of microvascular thrombosis in the progression of liver disease and highlight the molecular and cellular networks linking hemostasis to fibrosis in this context. We analyze the predictive and prognostic role of coagulation products as biomarkers of liver decompensation (ascites, variceal hemorrhage, and hepatic encephalopathy) and liver-related mortality. Finally, we evaluate the current evidence on the application of antiplatelet and anticoagulant therapies for prophylaxis of hepatic decompensation or prevention of the progression of liver fibrosis.

Identification of ORM1, vWF, SPARC, and PPBP as immune-related proteins involved in immune thrombocytopenia by quantitative LC-MS/MS

BACKGROUND

Immune thrombocytopenia (ITP) is a common autoimmune disease characterized by loss of immune tolerance to platelet autoantigens leading to excessive destruction and insufficient production of platelets.

METHOD

Quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed to detect the differentially expressed proteins in bone marrow samples from active ITP patients and normal controls.

RESULT

Our bioinformatic analysis identified two upregulated proteins (ORM1 and vWF) and two downregulated proteins (PPBP and SPARC) related to immune function. The four proteins were all found to be related to the tumor necrosis factor (TNF) -α signalling pathway and involved in the pathogenesis of ITP in KEGG pathway analysis.

CONCLUSION

Bioinformatics analysis identified differentially expressed proteins in bone marrow that are involved in the TNF-α signalling pathway and are related to the activation of immune function in ITP patients. These findings could provide new ideas for research on the loss of immune tolerance in ITP patients.

Von Willebrand factor and the thrombophilia of severe COVID-19: in situ evidence from autopsies

Background

COVID-19 is accompanied by a hypercoagulable state and characterized by microvascular and macrovascular thrombotic complications. In plasma samples from patients with COVID-19, von Willebrand factor (VWF) levels are highly elevated and predictive of adverse outcomes, especially mortality. Yet, VWF is usually not included in routine coagulation analyses, and histologic evidence of its involvement in thrombus formation is lacking.

Objectives

To determine whether VWF, an acute-phase protein, is a bystander, ie, a biomarker of endothelial dysfunction, or a causal factor in the pathogenesis of COVID-19.

Methods

We compared autopsy samples from 28 patients with lethal COVID-19 to those from matched controls and systematically assessed for VWF and platelets by immunohistochemistry. The control group comprised 24 lungs, 23 lymph nodes, and 9 hearts and did not differ significantly from the COVID-19 group in age, sex, body mass index (BMI), blood group, or anticoagulant use.

Results

In lungs, assessed for platelets by immunohistochemistry for CD42b, microthrombi were more frequent in patients with COVID-19 (10/28 [36%] vs 2/24 [8%]; P = .02). A completely normal pattern of VWF was rare in both groups. Accentuated endothelial staining was found in controls, while VWF-rich thrombi were only found in patients with COVID-19 (11/28 [39%] vs 0/24 [0%], respectively; P < .01), as were NETosis thrombi enriched with VWF (7/28 [25%] vs 0/24 [0%], respectively; P < .01). Forty-six percent of the patients with COVID-19 had VWF-rich thrombi, NETosis thrombi, or both. Trends were also seen in pulmonary draining lymph nodes (7/20 [35%] vs 4/24 [17%]; P = .147), where the overall presence of VWF was very high.

Conclusion

We provide in situ evidence of VWF-rich thrombi, likely attributable to COVID-19, and suggest that VWF may be a therapeutic target in severe COVID-19.

From the Discovery of ADAMTS13 to Current Understanding of Its Role in Health and Disease

ADAMTS13 (a disintegrin-like metalloprotease domain with thrombospondin type 1 motif, member 13) is a protease of crucial importance in the regulation of the size of von Willebrand factor multimers. Very low ADAMTS13 activity levels result in thrombotic thrombocytopenic purpura, a rare and life-threatening disease. The mechanisms involved can either be acquired (immune-mediated thrombotic thrombocytopenic purpura [iTTP]) or congenital (cTTP, Upshaw-Schulman syndrome) caused by the autosomal recessive inheritance of disease-causing variants (DCVs) located along the ADAMTS13 gene, which is located in chromosome 9q34. Apart from its role in TTP, and as a regulator of microthrombosis, ADAMTS13 has begun to be identified as a prognostic and/or diagnostic marker of other diseases, such as those related to inflammatory processes, liver damage, metastasis of malignancies, sepsis, and different disorders related to angiogenesis. Since its first description almost 100 years ago, the improvement of laboratory tests and the description of novel DCVs along the ADAMTS13 gene have contributed to a better and faster diagnosis of patients under critical conditions. The ability of ADAMTS13 to dissolve platelet aggregates in vitro and its antithrombotic properties makes recombinant human ADAMTS13 treatment a potential therapeutic approach targeting not only patients with cTTP but also other medical conditions.

The interplay of inflammation and coagulation in COVID-19 Patients receiving extracorporeal membrane oxygenation support

OBJECTIVE

Bleeding and thrombosis are common complications during Extracorporeal Membrane Oxygenation (ECMO) support for COVID-19 patients. We sought to examine the relationship between inflammatory status, coagulation effects, and observed bleeding and thrombosis in patients receiving venovenous (VV) ECMO for COVID-19 respiratory failure.

STUDY DESIGN

Cross-sectional cohort study.

SETTINGS

Quaternary care institution.

PATIENTS

The study period from April 1, 2020, to January 1, 2021, we included all patients with confirmed COVID-19 who received VV ECMO support.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Thirty-two patients were supported with VV ECMO during the study period, and 17 patients (53%) survived to hospital discharge. The ECMO nonsurvivors mean lactate dehydrogenase (LDH) levels were markedly elevated in comparison to survivors (1046 u/L [IQR = 509, 1305] vs 489 u/L [385 658], p = 0.003). Platelet/fibrinogen dysfunction, as reflected by the low Maximum Amplitude (MA) on viscoelastic testing, was worse in nonsurvivors (65.25 mm [60.68, 67.67] vs 74.80 mm [73.10, 78.40], p = 0.01). Time-group interaction for the first seven days of ECMO support, showed significantly lower platelet count in the nonsurvivors (140 k/ul [103, 170] vs 189.5 k/ul [ 146, 315], p < 0.001) and higher D-dimer in (21 μg/mL [13, 21] vs 14 μg/mL [3, 21], p < 0.001) in comparison to the survivors. Finally, we found profound statistically significant correlations between the clinical markers of inflammation and markers of coagulation in the nonsurvivors group. The ECMO nonsurvivors experienced higher rate of bleeding (73.3% vs 35.3%, p = 0.03), digital ischemia (46.7% vs 11.8%, p = 0.02), acute renal failure (60% vs 11.8%, p = 0.01) and bloodstream infection (60% vs 23.5%, p = 0.03).

CONCLUSION

The correlation between inflammation and coagulation in the nonsurvivors supported with VV ECMO could indicate dysregulated inflammatory response and worse clinical outcomes.

Sponge-like nano-system suppresses tumor recurrence and metastasis by restraining myeloid-derived suppressor cells-mediated immunosuppression and formation of pre-metastatic niche

Tumor recurrence and metastasis still greatly limit the therapeutic efficiency on the majority of postoperative clinical cases. With the aim to realize more powerful treatment outcomes on postoperative malignant tumors, a sponge-like neutrophil membrane-coated nano-system (NM/PPcDG/D) was fabricated to inhibit tumor recurrence and metastasis by inhibiting the recruitment and functions of myeloid-derived suppressor cell (MDSCs), which reinforced anti-tumor immunity and also suppressed pulmonary metastasis by inhibiting the formation of pre-metastatic niche (PMN). Firstly, PPcDG/D nanoparticles (NPs) were formulated by the self-assembling and crosslinking of synthesized redox-responsive polymer (PPDG) with doxorubicin (DOX) loading in the nanocore (PPcDG/D), followed by coating with activated neutrophils membrane to fabricate biomimetic NM/PPcDG/D. The sponge-like NM/PPcDG/D not only showed obvious natural tropism to postoperative inflammatory site, but also inhibited the recruitment and functions of MDSCs, thus relieved MDSCs-mediated immunosuppression. Additionally, NM/PPcDG/D also suppressed the formation of PMN to inhibit pulmonary metastasis by reducing the recruitment of MDSCs, decreasing the permeability of pulmonary vessels and inhibiting the implantation of circulating tumor cell (CTCs). Eventually, this fabricated NM/PPcDG/D NPs significantly inhibited tumor recurrence and metastasis on postoperative triple negative breast cancer (TNBC) model, presenting a promising therapeutic strategy on postoperative malignant tumors. STATEMENT OF SIGNIFICANCE: Myeloid-derived suppressor cells (MDSCs) play important roles in accelerating tumor recurrence and metastasis by promoting the establishment of immunosuppression in postoperative inflammatory regions and facilitating the formation of pulmonary pre-metastasis niche (PMN). In order to achieve enhanced suppression of recurrence and metastasis, a sponge-like NM/PPcDG/D nano-system was designed and fabricated. This nano-system is also the first attempt to integrate the regulation effects of a nano-sponge and anti-inflammatory agent to achieve enhanced multi-mode manipulation of MDSCs. Ultimately, NM/PPcDG/D powerfully restrained the recurrence and spontaneous metastasis on TNBC model. This article also revealed the particular roles of MDSCs involved in the regulation networks of postoperative recurrence and metastasis, immunosuppression and inflammation.

Immune thrombotic thrombocytopenic purpura: Spotlight on long-term outcomes and survivorship

Advances in diagnosis and treatment have dramatically improved survival of acute immune thrombotic thrombocytopenic purpura (iTTP) and iTTP has evolved from an acute fatal condition to a chronic relapsing disorder. In addition to the risk of iTTP relapse, iTTP survivors are at risk of multiple adverse health outcomes including higher than expected rates of all-cause mortality, increased rates of stroke and other cardiovascular disease, and higher rates of morbidities such as obesity, hypertension, and autoimmune disorders. iTTP survivors also report neurocognitive impairment, depression, and reduced quality of life. Women with iTTP are at risk for recurrent iTTP, preeclampsia, and other maternal and fetal complications in subsequent pregnancies. ADAMTS13 activity during clinical remission has emerged as an important targetable risk factor for iTTP relapse and other outcomes including stroke and all-cause mortality. This review summarizes current literature regarding the epidemiology and potential mechanisms for adverse long-term sequelae of iTTP, outlines current best practices in iTTP survivorship care, and highlights a research agenda to improve long-term iTTP outcomes.

Is Endothelial Activation a Critical Event in Thrombotic Thrombocytopenic Purpura?

Thrombotic thrombocytopenic purpura (TTP) is a severe thrombotic microangiopathy. The current pathophysiologic paradigm suggests that the ADAMTS13 deficiency leads to Ultra Large-Von Willebrand Factor multimers accumulation with generation of disseminated microthrombi. Nevertheless, the role of endothelial cells in this pathology remains an issue. In this review, we discuss the various clinical, in vitro and in vivo experimental data that support the important role of the endothelium in this pathology, suggesting that ADAMTS13 deficiency may be a necessary but not sufficient condition to induce TTP. The "second hit" model suggests that in TTP, in addition to ADAMTS13 deficiency, endogenous or exogenous factors induce endothelial activation affecting mainly microvascular cells. This leads to Weibel-Palade bodies degranulation, resulting in UL-VWF accumulation in microcirculation. This endothelial activation seems to be worsened by various amplification loops, such as the complement system, nucleosomes and free heme.

Neutrophil extracellular trap stabilization by platelet factor 4 reduces thrombogenicity and endothelial cell injury

Neutrophil extracellular traps (NETs) are abundant in sepsis, and proposed NET-directed therapies in sepsis prevent their formation or accelerate degradation. Yet NETs are important for microbial entrapment, as NET digestion liberates pathogens and NET degradation products (NDPs) that deleteriously promote thrombosis and endothelial cell injury. We proposed an alternative strategy of NET-stabilization with the chemokine, platelet factor 4 (PF4, CXCL4), which we have shown enhances NET-mediated microbial entrapment. We now show that NET compaction by PF4 reduces their thrombogenicity. In vitro, we quantified plasma thrombin and fibrin generation by intact or degraded NETs and cell-free (cf) DNA fragments, and found that digested NETs and short DNA fragments were more thrombogenic than intact NETs and high molecular weight genomic DNA, respectively. PF4 reduced the thrombogenicity of digested NETs and DNA by interfering, in part, with contact pathway activation. In endothelial cell culture studies, short DNA fragments promoted von Willebrand factor release and tissue factor expression via a toll-like receptor 9-dependent mechanism. PF4 blocked these effects. Cxcl4-/- mice infused with cfDNA exhibited higher plasma thrombin anti-thrombin (TAT) levels compared to wild-type controls. Following challenge with bacterial lipopolysaccharide, Cxcl4-/- mice had similar elevations in plasma TAT and cfDNA, effects prevented by PF4 infusion. Thus, NET-stabilization by PF4 prevents the release of short fragments of cfDNA, limiting the activation of the contact coagulation pathway and reducing endothelial injury. These results support our hypothesis that NET-stabilization reduces pathologic sequelae in sepsis, an observation of potential clinical benefit.

Effects of convalescent plasma infusion on the ADAMTS13-von Willebrand factor axis and endothelial integrity in patients with severe and critical COVID-19

Background

Convalescent plasma infusion (CPI) was given to patients with COVID-19 during the early pandemic with mixed therapeutic efficacy. However, the impacts of CPI on the ADAMTS13-von Willebrand factor (VWF) axis and vascular endothelial functions are not known.

Objectives

To determine the impacts of CPI on the ADAMTS13-VWF axis and vascular endothelial functions.

Methods

Sixty hospitalized patients with COVID-19 were enrolled in the study; 46 received CPI and 14 received no CPI. Plasma ADAMTS13 activity, VWF antigen, endothelial syndecan-1, and soluble thrombomodulin (sTM) were assessed before and 24 hours after treatment.

Results

Patients with severe and critical COVID-19 exhibited significantly lower plasma ADAMTS13 activity than the healthy controls. Conversely, these patients showed a significantly increased VWF antigen. This resulted in markedly reduced ratios of ADAMTS13 to VWF in these patients. The levels of plasma ADAMTS13 activity in each patient remained relatively constant throughout hospitalization. Twenty-four hours following CPI, plasma ADAMTS13 activity increased by ∼12% from the baseline in all patients and ∼21% in those who survived. In contrast, plasma levels of VWF antigen varied significantly over time. Patients who died exhibited a significant reduction of plasma VWF antigen from the baseline 24 hours following CPI, whereas those who survived did not. Furthermore, patients with severe and critical COVID-19 showed significantly elevated plasma levels of syndecan-1 and sTM, similar to those found in patients with immune thrombotic thrombocytopenic purpura. Both syndecan-1 and sTM levels were significantly reduced 24 hours following CPI.

Conclusion

Our results demonstrate the relative deficiency of plasma ADAMTS13 activity and endothelial damage in patients with severe and critical COVID-19, which could be modestly improved following CPI therapy.