Role of Microparticles in the Coagulopathy of Acute Promyelocytic Leukemia
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|ClinicalTrials.gov Identifier: NCT02991066|
Recruitment Status : Recruiting
First Posted : December 13, 2016
Last Update Posted : April 24, 2018
|Condition or disease|
|Acute Promyelocytic Leukemia|
The investigators plan to measure routine laboratory parameters of coagulation and fibrinolysis, the procoagulant or profibrinolytic activity of microparticles (MPs), and explore the role of the procoagulant and profibrinolytic activating factor of MPs in the pathogenesis of coagulopathy in patients with APL.
i. Dynamic turbidimetry of plasma clot formation. The effects of MPs on the kinetics of fibrin formation and on the optical properties of clots are studied using dynamic turbidimetry of re-calcified plasma samples (platelet-free plasma and microparticle-depleted plasma) without adding any clotting activator. Clotting of plasma samples induced by Ca2+ is followed by monitoring the optical density at λ = 405 nm at 37 °C.
ii. Thrombin generation assay. The amount of thrombin formed in plasma upon re-calcification is measured directly using a modified thrombin generation test . Because fibrin interferes with colorimetric measurements, plasma samples are first defibrinated by adding reptilase followed by incubation at 37 °C. The clots are removed. Then a chromogenic substrate for thrombin is added to the plasma samples. Thrombin generation is started by adding CaCl2 with simultaneous recording of the absorbance at λ = 405 nm.
iii. Thrombin generating capacity of the MPs. MPs are reconstituted in defibrinated (reptilase treated), normal pooled microparticle-depleted plasma. Then a chromogenic substrate for thrombin is added to the samples. Thrombin generation is started by adding CaCl2 with simultaneous recording of the absorbance at λ = 405 nm.
iv. Thrombin generation inhibitory experiments. The following inhibitors are pre-incubated with the microparticles: Annexin V, anti-human tissue factor (TF) and irrelevant control immunoglobulin G (IgG). Then repeats the experiment iii.
v. Fibrinolytic activity. Incubate a fixed concentration of plasminogen with the plasma samples in the presence of a chromogenic substrate selective for plasmin. Plasmin formed from plasminogen bound at the surface of microparticles cleaves the chromogenic substrate and the released p-nitroaniline is detected by measuring A405nm as a function of time.
vi. Determination of fibrinolytic activity on microparticles. The capacity of microparticles to activate plasminogen is determined by incubating a fixed concentration of plasminogen (1mM) with the microparticles with or without t-PA and/or u-PA in the presence of a chromogenic substrate selective for plasmin. Plasmin formed from plasminogen bound at the surface of microparticles cleaves the chromogenic substrate and the released p-nitroaniline is detected by measuring A405nm.
vii. Fibrinolytic activity inhibitory experiments. The following inhibitors are pre-incubated with the microparticles: anti-human tissue type plasminogen activator (tPA) , anti-human urokinase type plasminogen activator (uPA), and respective irrelevant control IgGs; ε-aminocaproic acid and plasminogen activator inhibitor-1 (PAI-1).Then repeat the experiment vi.
|Study Type :||Observational|
|Estimated Enrollment :||20 participants|
|Official Title:||Role of Microparticles in the Coagulopathy of Acute Promyelocytic Leukemia|
|Study Start Date :||October 2014|
|Estimated Primary Completion Date :||December 2019|
|Estimated Study Completion Date :||December 2020|
patients with de novo acute promyelocytic leukemia with hemorrhage.
- Change From Baseline in the Levels and Cellular Origin of MPs at 5 Weeks [ Time Frame: 5 weeks ]Demonstration that the some procoagulant or profibrinolytic activating factors expressed on MP in APL patients' plasma associate with the thrombin generating capacity and fibrinolytic activity of patients' plasma.
Biospecimen Retention: Samples Without DNA
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02991066
|Contact: Jin Zhou, MD, PhDemail@example.com|
|the First Affiliated Hospital of Harbin Medical University||Recruiting|
|Harbin, Heilongjiang, China, 150001|
|Contact: Jin Zhou, MD, PhD 008645185555951 firstname.lastname@example.org|
|Study Chair:||Jin Zhou, MD, PhD||First Affiliated Hospital of Harbin Medical University|