VWF/ADAMTS13 Ratios Are Potential Markers of Immunothrombotic Complications in Patients with COVID-19: A Cross-Sectional Study

Abstract

BACKGROUND. COVID-19 is a prothrombotic disease, characterized by both arterial and venous thrombosis. The pathogenesis of coagulopathy in COVID-19 is multifactorial, with activation of endothelial cells, platelets, neutrophils, and other immune system effectors playing crucial roles. High levels of von Willebrand factor (VWF) and reduced levels of ADAMTS13 have been observed in COVID-19, sepsis, and immunothrombotic states, and an elevated VWF/ADAMTS13 ratio has been previously described in ischemic stroke1. In this study, we sought to evaluate potential associations of VWF activity and antigen ratios to ADAMTS13 with clinical outcomes in hospitalized patients with COVID-19 and to compare these ratios with other cytokines and markers of inflammation in critical illness. METHODS. Institutional Review Board approval was obtained for this study. Blood was collected from 49 hospitalized patients with a confirmed diagnosis of COVID-19 between April 13 and April 24, 2020, which included 40 patients in an intensive care unit and 9 on a non-ICU unit. Medical records were reviewed, and patient characteristics including age, sex, comorbidities, pertinent medications, imaging studies, history of arterial or venous thrombosis, and other pertinent patient information were compiled. Blood was collected in sodium citrate tubes and centrifuged at 4000 rpm for 20 minutes, with the resulting plasma supernatant used for further testing. Measurements of VWF antigen and VWF activity were performed on an ACL TOP machine using our institution's standard clinical laboratory protocol. Biomarker profiling analyses were performed at Eve Technologies (Calgary, Alberta, Canada). Statistical analysis was performed using GraphPad Prism (v8.4.3, GraphPad Software, San Diego, CA) and R (v4, R Core Team, 2020). P values <0.05 were considered statistically significant. RESULTS. The median age was 64 years; 36 (73%) were male, 11 (22.4%), 29 (59.2%), and 9 (18.4%) had BMI<25, between 25 and 40, and >40 kg/m2, respectively. The ratio of VWF activity/ADAMTS13 was significantly higher in patients with higher BMI (median [interquartile range, IQR] VWF activity/ADAMTS13 ratios: 0.66 [0.39-0.88] for BMI<25 kg/m2, 0.865 [0.769-1.102] for BMI 25-40 kg/m2, and 1.041 [0.747-2.032] for BMI>40 kg/m2; p = 0.0408, Kruskal-Wallis test). In patients who required mechanical ventilation, median [IQR] VWF activity/ADAMTS13 was 0.876 [0.75-1.769] vs 0.792 [0.566-0.932] for those who did not (p = 0.0497, Mann-Whitney U-test). The difference for the VWF antigen/ADAMTS13 ratio was more pronounced, 1.32 [0.991-2.456] vs 0.981 [0.628-1.162] (p = 0.0045, Mann-Whitney U-test). There was also a significant correlation between both VWF activity/ADAMTS13 and VWF antigen/ADAMTS13 ratios and neutrophil indices such as absolute neutrophil count (R = 0.57, p <0.0001 and R = 0.54, p = 0.0001, respectively) and neutrophil to lymphocyte count (R = 0.6, p <0.0001 and R = 0.57, p <0.0001, respectively). We also found significant correlations of these ratios with markers of neutrophils activation (HGF, resistin, and lipocalin-2; Figure 1). CONCLUSIONS. Ratios VWF activity/ADAMTS13 and VWF antigen/ADAMTS13 are elevated in patients with more severe COVID-19 disease and correlate with markers of neutrophils activation. These findings and that azurophillic granules in neutrophils contain α-defensins implicated in thrombosis2 suggest possible mechanistic links among VWF, ADAMTS13, contact pathway, and neutrophil function in mediating immunothrombotic complications in COVID-19, which might highlight potential therapeutic targets to attenuate the severity of coagulopathy and merit further investigation with a larger cohort of patients. REFERENCES 1. Taylor A, et al. Blood Adv. 2020;4(2):398-407 2. Abu-Fanne R, et al. Blood. 2019;133(5):481-493 Disclosures No relevant conflicts of interest to declare.

Plasma haemostatic levels in COVID-19 patients and healthy controls: A comparative study at Two tertiary Hospitals in Zambia

“…IL-6 soluble IL-6 receptor (sIL-6R) complex triggers release of ULVWF multimers from endothelial cells, but to a lesser extent than IL-8 or TNF-α (Kichloo et al, 2020).. Conversely, IL-6 inhibits a ADAMTS13 and thus reducing ULVWF multimer cleavage and enhancing platelet adhesion and aggregation (Kichloo et al, 2020). Our study revealed that higher mean Vwf/ADAMTS13 Ratio correlated with COVID-19 severity and this is consistent with the study by Madeeva et al (2020) who reported an increase in VWF antigen and a reduction in ADAMTS13 activity in COVID-19 patients, which is related to disease severity and could predict poor clinical outcomes. They also suggested that the ADAMTS13 activity reduction could be a marker associated with COVID-19 compared to other non-critical medical conditions.…”

COVID-19 Sepsis: Pathogenesis and Endothelial Molecular Mechanisms Based on “Two-Path Unifying Theory” of Hemostasis and Endotheliopathy-Associated Vascular Microthrombotic Disease, and Proposed Therapeutic Approach with Antimicrothrombotic Therapy

“… 6 This protease was found to be insufficient when tested in severe COVID-19 patients. 82 , 83 , 90 , 96 , 98 This important proteolytic enzyme is needed to cleave the excess ULVWF multimers that are released from damaged ECs and to prevent microthrombogenesis.…”

Isaridin E Protects against Sepsis by Inhibiting Von Willebrand Factor-Induced Endothelial Hyperpermeability and Platelet–Endothelium Interaction

“…ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) is responsible for cleaving ULvWF into smaller pieces, thereby reducing its plasma levels and activity. Elevated vWF/ADAMTS-13 ratios have been observed in sepsis and COVID-19 and are positively correlated with high ICU mortality [6,7]. Recently, the vWF/ADAMTS-13 axis has emerged as a potential therapeutic target for both sepsis and COVID-19.…”