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Chemotherapy‐induced thrombin generation via procoagulant endothelial microparticles is independent of tissue factor activity
Author(s) -
LECHNER D.,
KOLLARS M.,
GLEISS A.,
KYRLE P. A.,
WELTERMANN A.
Publication year - 2007
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/j.1538-7836.2007.02788.x
Subject(s) - tissue factor , thrombin , umbilical vein , cisplatin , flow cytometry , endothelial stem cell , viability assay , annexin , apoptosis , microbiology and biotechnology , endothelium , pharmacology , chemistry , in vitro , immunology , biology , medicine , platelet , endocrinology , chemotherapy , biochemistry , coagulation
Summary. Background: Cisplatin‐based chemotherapy predisposes cancer patients to thromboembolic events. Objectives: To investigate whether endothelial damage, via formation of procoagulant endothelial microparticles (EMPs), contributes to cisplatin‐related hypercoagulability. Methods: Cell viability and caspase‐3/7 activities were assessed in two endothelial cell (EC) lines [human umbilical vein ECs (HUVECs) and human pulmonary microvascular ECs (HMVEC‐Ls)] after exposure to cisplatin (1, 2.5, 5, 10 and 20 μ m ) for up to 120 h. Counts and procoagulant activity of EMPs were measured by flow cytometry and a thrombin generation assay, respectively. Tissue factor (TF) antigen and TF‐dependent procoagulant activity of EMP were determined by enzyme‐linked immunosorbent assay and a novel functional assay. Results: By inducing apoptosis, cisplatin dose‐ and time‐dependently decreased the viability of confluent HUVECs and HMVEC‐Ls. Progression of EC death was accompanied by an increased release of EMPs (relative increase at 20 μ m cisplatin for 48 h vs. control: HUVECs 6.5‐fold, P < 0.001; HMVEC‐Ls 18.4‐fold, P < 0.001). EMPs were highly procoagulant (relative increase at 20 μ m cisplatin for 48 h vs. control: HUVECs 2.5‐fold, P < 0.001; HMVEC‐Ls 5.9‐fold, P < 0.001). EMP‐driven thrombin generation, however, was not dependent on TF: TF expression and TF procoagulant activity levels on microparticles were only marginal and EMP‐associated thrombin generation remained unchanged when the extrinsic pathway was blocked by omission of factor VIIa and/or incubation with an anti‐human TF antibody. In contrast, blocking of phospholipids by annexin V markedly diminished EMP‐associated procoagulant activity. Conclusions: In vitro , cisplatin induced the release of EMPs that showed TF‐independent procoagulant activity.