An international study on the feasibility of a standardized combined plasma clot turbidity and lysis assay: communication from the SSC of the ISTH

Pieters, Marlien; Philippou, Helen; Undas, Anetta; Lange, Zelda de; Rijken, D.C.; Mutch, Nicola J.

doi:10.1111/jth.14002

Cited by 102 publications

(96 citation statements)

References 35 publications

(34 reference statements)

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“…The following parameters were recorded: a) Clot maximum absorbance (arbitrary units, au) indicating network density, b) Lysis time (Lys50 MA , seconds) corresponding to time from full clot formation to 50% lysis, indicating fibrinolytic potential; c) Time to complete lysis (Lys T , seconds) indicating the time from clot maximum absorbance to the time for absorbance values to return to baseline; d) Lysis area (au), reflecting the balance between clot formation and lysis. Differences in clot lysis time were confirmed using protocol previously described by Pieters et al with tPA concentration of 18-20 ng/ml [16]. Clot lysis time was calculated as the time from the midpoint, from clear to maximum turbidity, to the midpoint in the transition from maximum turbidity to the final baseline turbidity.…”

Section: Clot Permeability and Lysabilitymentioning

confidence: 99%

Sex-specific alteration to α2-antiplasmin incorporation in patients with type 2 diabetes

Bryk

Siudut

Broniatowska

et al. 2020

Thrombosis Research

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A B S T R A C TBackground: Type 2 diabetes mellitus (T2DM) is associated with hypofibrinolysis and increased factor XIIImediated α2-antiplasmin incorporation into the fibrin clot. It is unclear whether there are sex-related differences in α2-antiplasmin incorporation in relation to impaired clot lysis in T2DM. Aim: We investigated α2-antiplasmin incorporation into fibrin clots as a determinant of clot lysability in patients of both sexes with T2DM. Methods: In a group of 113 T2DM patients, 54 (47.8%) of which were women, we investigated α2-antiplasmin incorporation using an in-house sandwich enzyme-linked immunoassay and plasma clot lysis by turbidimetry, along with fibrinogen and thrombin generation using calibrated automated thrombogram and factor XIII activity. Results: Female patients had 15.2% greater α2-antiplasmin incorporation into the fibrin clot (p = 0.008) and slightly higher plasma α2-antiplasmin concentration (p = 0.005) along with 8.4% longer time to 50% lysis (Lys50 MA , p = 0.012) compared with men. Female patients had enhanced thrombin generation represented by shorter lag phase (p = 0.042), shorter time to peak (p = 0.033), and higher endogenous thrombin potential (p = 0.003) compared with men, while factor XIII activity was comparable between sexes (p = 0.085). On multivariate regression, patient sex and glycated hemoglobin (HbA1c) level were the predictors of α2-antiplasmin incorporation in the entire patient group, while α2-antiplasmin incorporation was associated with Lys50 MA , as were fibrinogen, male sex and body-mass index. Conclusions: This study suggests that a more compromised fibrinolysis in diabetic women when compared with men could be in part mediated by increased α2-antiplasmin incorporation into the fibrin.

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Section: Clot Permeability and Lysabilitymentioning

confidence: 99%

Sex-specific alteration to α2-antiplasmin incorporation in patients with type 2 diabetes

Bryk

Siudut

Broniatowska

et al. 2020

Thrombosis Research

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“…The initial rate of change was determined from the slope of the line at the midpoint between initial baseline and maximum absorbance as described. 26 In contrast, the A2 (E1567A) mutant did not affect the rate of fibrin polymerization (supplemental Figure 3A-B), suggesting that the A2 protein influences the rate of fibrin formation.…”

Section: A2 Protein Influences the Initial Change Of The Fibrin Formamentioning

confidence: 90%

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation

et al. 2020

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Systemic inflammation can lead to coagulopathy and disseminated intravascular coagulation (DIC). In prior studies, the recombinant A2 domain of human von Willebrand factor (VWF; A2 protein) attenuated DIC and decreased mortality in lipopolysaccharide (LPS)-treated mice. Here, we performed studies to dissect the mechanism by which the A2 protein moderates DIC. We used confocal microscopy to analyze the fibrin clot structure in plasma from healthy humans and endotoxemic mice, turbidity assays to examine fibrin polymerization, and a murine model for LPS-induced DIC and introduced a loss-of-function mutation into the A2 protein for fibrin. The mutation of the residue E1567 located in the α2 helix of the folded A2 domain of VWF inhibited binding activity for fibrin, possibly mapping a novel region containing a putative binding site for fibrin. The A2 protein increased the initial rate of change of fibrin polymerization, intercalated into the fibrin network, and modified the resultant clot structure in vitro. Furthermore, ex vivo experiments using plasma from mice with endotoxemia treated with the A2 protein revealed an increased rate of fibrin formation and an altered clot structure as compared with plasma from nontreated sick animals. Moreover, and in contrast to the A2 mutant, the A2 protein improved survival and reduced fibrin deposition and microvascular thrombosis in mice with endotoxemia-induced DIC. Importantly, in vivo and in vitro studies indicated that the A2 protein did not affect experimental thrombosis. Thus, we provide evidence for a novel treatment to attenuate systemic inflammation-induced coagulopathy/DIC via targeting fibrin formation, without an increased risk for bleeding.

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“…The turbidimetric assay used in this project was developed by integrating multiple previous studies of plasma clot formation and lysis in the nononcologic setting. 18,20À22,38 In light of the at times conflicting definitions of clot formation and lysis parameters in previous studies 52 we have strictly prespecified these definitions and provided an easy-to-use program for automatic extraction of these parameters from raw absorbance measurements. While the current assay shares many similarities with the above referenced assays from previous studies, its major difference is that it uses a tissue-factor based reagent rather than thrombin as the stimulant for clot induction.…”

Section: Discussionmentioning

confidence: 99%

Ex vivo properties of plasma clot formation and lysis in patients with cancer at risk for venous thromboembolism, arterial thrombosis, and death

Posch

Hofer

Thaler

et al. 2020

Translational Research

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A prothrombotic state is frequently observed in patients with cancer and contributes to the risks of venous thromboembolism (VTE), arterial thromboembolism (ATE), tumor progression, and death. Altered ex vivo properties of plasma clot formation and lysis have been observed in patients with cancer. The aim of this prospective study was to comprehensively characterize the relationship between plasma clot properties, inflammation, hypercoagulability, thrombotic complications, and mortality in patients with cancer using a tissue-factor-based turbidimetric assay of clot formation and lysis. Turbidity parameters were determined in 815 patients with newly-diagnosed or recurrent cancer and 97 healthy controls. Patients were followed-up for 2 years and rates of VTE (n = 72 events), ATE (n = 21 events), and death (n = 304 events) were assessed. Compared to controls, cancer patients' turbidity profiles showed an increased clot formation potential and higher resistance toward fibrinolysis. Elevated biomarkers of inflammation and hemostasis, such as C-reactive protein, FVIII, and thrombin generation explained substantial amounts of variation in turbidity parameters. In a prospective analysis, altered parameters of clot formation identified cancer patients at high risk of ATE (Hazard ratio [HR] per doubling of peak absorbance: 4.43, 95% CI: 1.50À13.07, P = 0.007) and death (HR per doubling of peak absorbance: 2.73, 2.00À3.72, P< 0.0001); these findings were independent of other prognostic covariates. Contrarily, turbidity parameters were not associated with risk of VTE (HR per doubling of peak absorbance: 1.15, 0.66À2.01, P = 0.62). We conclude that patients with cancer have altered ex vivo properties of clot formation which predict risks of ATE and mortality but not VTE.

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An international study on the feasibility of a standardized combined plasma clot turbidity and lysis assay: communication from the SSC of the ISTH

Cited by 102 publications

References 35 publications

Sex-specific alteration to α2-antiplasmin incorporation in patients with type 2 diabetes

Sex-specific alteration to α2-antiplasmin incorporation in patients with type 2 diabetes

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation

Ex vivo properties of plasma clot formation and lysis in patients with cancer at risk for venous thromboembolism, arterial thrombosis, and death

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