thromboplastin and Coronary-Restenosis

Because of its unique position at the convergence point of the intrinsic (contact) and extrinsic (tissue factor/factor VIIa) pathways in the coagulation system, coagulation factor Xa (FXa) has been a theoretically interesting therapeutic target for antithrombotic drugs for many years. More recently, the discovery of naturally occurring FXa inhibitors, such as tick anticoagulant peptide and antistasin, has helped substantiate FXa as a desirable target by demonstrating the efficacy and potential safety advantages of FXa inhibition over conventional antithrombotic therapy. These discoveries led to the design and development of many small-molecule inhibitors of FXa, which have provided potent and selective tools for evaluating the potential role of FXa in various diseases. In addition, these advances have been instrumental in defining the biology of FXa and have aided in the discovery of specific receptors and intracellular signaling pathways for FXa that may be important in the progression of, or the response to, various diseases.

Topics: Animals; Cell Adhesion; Clinical Trials as Topic; Coronary Restenosis; Cysteine Endopeptidases; Cytokines; Factor Xa; Factor Xa Inhibitors; Graft Occlusion, Vascular; Humans; Hyperplasia; Inflammation; MAP Kinase Signaling System; Neoplasm Proteins; Neoplasms; Platelet-Derived Growth Factor; Receptor, PAR-2; Receptors, Platelet-Derived Growth Factor; Receptors, Thrombin; Sepsis; Thromboplastin; Up-Regulation

The predictability of the whole-blood tissue factor levels for restenosis after coronary angioplasty is uncertain. We first probed in depth the association between plasma tissue factor concentrations and the development of restenosis after coronary intervention with an animal pathological model.. Thirty pigs were used and their coronary arteries were injured for the dilatation of balloons. Morphological measurements include neointimal area, injury score and the extent of area stenosis. Whole-blood tissue factor levels were measured before and after intervention. The circulating tissue factor levels increased significantly after intervention (baseline value, 328.54 ± 47.46 pg/ml; at 30th minute, 618.96 ± 119.08 pg/ml; at 24th hour, 639.34 ± 116.21 pg/ml) (p < 0.01), and the degrees of tissue factor changes correlated positively to the neointimal hyperplasty (r(30th min) = 0.751, r(24th hour) = 0.72, p < 0.01). There was no significant difference with the baseline whole blood tissue factor (TF) levels between restenotic and non-restenotic cases (330.83 ± 47.32 vs. 325.1 ± 49.57 pg/ml) (p > 0.05). The injury of media led to the most distinctive changes of blood tissue factor (p < 0.01).. Higher values of whole-blood tissue factor may be a predictor of restenosis, and the damaged media might be the main reason of the tissue factor increase.

Topics: Angioplasty, Balloon, Coronary; Animals; Coronary Artery Disease; Coronary Restenosis; Male; Multivariate Analysis; Muscle, Smooth, Vascular; Predictive Value of Tests; Prognosis; Risk Factors; Swine; Thromboplastin; Time Factors

The NF-kappaBeta transcription factors modulate the expression of tissue factor (TF), E-selectin (CD62E) and vascular cell adhesion molecule-1 (VCAM-1), which are essential for thrombosis and inflammation. We have previously shown that andrographolide (Andro) covalently modifies the reduced cysteine(62) of p50 - a major subunit of NF-kappaBeta transcription factors, thus blocking the binding of NF-kappaBeta transcription factors to the promoters of their target genes, preventing NF-kappaBeta activation and inhibiting inflammation in vitro and in vivo. Here we report that Andro, but not its inactive structural analog 4H-Andro, significantly suppressed the proliferation of arterial neointima ( approximately 60% reduction) in a murine model of arterial restenosis. Consistently, p50(-/-) mice manifested attenuated neointimal hyperplasia upon arterial ligation. Notably, the same dosage of Andro did not further reduce neointimal formation in p50(-/-) mice, which implicates the specificity of Andro on p50 for treating experimental arterial restenosis. The upregulation of NF-kappaBeta target genes, including TF, E-selectin and VCAM-1, and the increased deposition of leukocytes (mainly CD68+ macrophages) were clearly detected within the injured arterial walls, all of which were significantly abolished by treatment with Andro or genetic deletion of p50. The expression of TF, E-selectin and VCAM-1 was also markedly upregulated in the patient sample of thrombotic vasculitis, indicating the clinical relevance of NF-kappaBeta activation in the pathogeneses of occlusive arterial diseases. Our data thus indicate that, by the downregulation of the NF-kappaBeta target genes that are critical in thrombosis and inflammation, specific inhibitors of p50, such as Andro, may be therapeutically valuable for preventing and treating thrombotic arterial diseases, including neointimal hyperplasia in arterial restenosis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Coronary Restenosis; Coronary Vessels; Cysteine; Disease Models, Animal; Diterpenes; E-Selectin; Gene Deletion; Humans; Hyperplasia; Inflammation; Macrophages; Mice; Mice, Knockout; NF-kappa B p50 Subunit; Thromboplastin; Tunica Intima; Up-Regulation; Vascular Cell Adhesion Molecule-1

Increased thrombogenicity of drug-eluting stents (DESs) has recently been reported. The aim of the present study was to investigate the prothrombogenic effect of DESs and Bare stents, and determine factors predictive of acute stent thrombosis (AST) in preclinical experiments using new stent design or coating. Circulating pre- and post-stenting parameters of platelet activation (mean platelet volume, MPV; platelet distribution width, platelet large cell ratio), thrombin activation (thrombin-antithrombin complex, TAT and prothrombin fragments, F1+2), tissue factor antigen (TF-ag) and -activity (TF-act) and plasminogen activator inhibitor-1 (PAI-1) were measured in 141 consecutive pigs. Stent implantations were performed after pretreatment with aspirin and clopidogrel with unfractionated heparin anticoagulation. Nineteen pigs (groups AST-DES, n = 12; and AST-Bare, n = 7) died mean 6.3 +/- 2.9 h after stent implantation from AST. The remaining 122 control (C) pigs (groups C-DES, n = 76, and C-Bare, n = 46) survived the 1-month follow-up. Non-significantly elevated levels of post-stent F1+2 and TAT were measured in AST groups. Post-stenting MPV was increased significantly in the groups ASTDES and AST-Bare as compared with the groups C-DES and C-Bare (11.73 +/- 1.12 and 11.6 +/- 0.68 vs. 8.85 +/- 0.78 and 9.04 +/- 0.81 fL; p < 0.001), similarly to TF-ag (189.1 +/- 87.5 and 127 +/- 34.9 vs. 42.5 +/- 24.6 and 35.3 +/- 37.6 pg/ml; p < 0.001, respectively), Tfact (3.23 +/- 0.95 and 2.73 +/- 1.68 vs. 1.43 +/- 1.12 and 1.61 +/- 1.31 pM; p < 0.01, respectively) and PAI-1 (99.1 +/- 15.8 and 99 +/- 14.7 vs.53.4 +/- 40.2 and 46.9 +/- 42.4 ng/ml;p < 0.01, respectively). Multivariate analysis revealed elevated post-stenting plasma levels of TF-ag (p = 0.016) and MPV (p = 0.001) as independent risk factors for developing AST within the first 24 h in a porcine coronary stent model.

Topics: Angiography; Animals; Blood Platelets; Coronary Restenosis; Coronary Vessels; Fibrinolysis; Microscopy, Electron, Scanning; Platelet Activation; Stents; Swine; Thrombin; Thromboplastin; Thrombosis; Time Factors

Intracoronary brachytherapy (ICBT) effectively reduces restenosis but is associated with late thrombosis. Since tissue factor (TF) is an important mediator of arterial thrombosis, we tested the hypothesis that ICBT results in persistently augmented TF expression. Coronary arteries from 12 pigs were randomized to: control (C; no injury), oversized balloon injury (BI), or BI followed by ICBT. Animals were sacrificed at 1, 7, 14, or 60 days postprocedure, and coronary arteries collected for expression analyses and immunostaining. ICBT-treated arteries had higher TF antigen and activity at all time-points compared to BI arteries (Western blot: 16 571 +/- 2090 vs 10 135 +/- 2939 densitometric units, p = 0.001; ELISA: 0.42 +/- 0.13 nM vs 0.25 +/- 0.14 nM, p = 0.001; TF activity assay: 0.303 +/- 0.11 nM vs 0.18 +/- 0.07 nM, p = 0.01; immunohistochemical staining: 30.6 +/- 6.6% vs 11.5% +/- 3.2%, p = 0.01). TF expression increased following BI, increased further following ICBT, and persisted for the duration of the study. We conclude that TF expression increases after BI, but is further increased and persists for a longer duration following ICBT, suggesting that a TF-mediated mechanism may play a role in late thrombosis following ICBT.

Topics: Animals; Blotting, Western; Brachytherapy; Catheterization; Coronary Restenosis; Coronary Thrombosis; Coronary Vessels; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Swine; Thromboplastin

This study was designed to assess the time course and nature of the vascular procoagulant response after 1.5-fold balloon overstretch injury of the coronary arteries in pigs. Arteries were excised for chromogenic assay of bound factor (F)Xa and thrombin at 24 h, 3 days, 1 week, or 2 weeks after injury. FXa at the site of injury remained elevated for 1 week (4.9 +/- 5.9 microg cm(-2), n = 10), compared with non-injured control arteries (0.4 +/- 0.2 microg cm(-2), n = 18, P = 0.00025), while thrombin was increased only at 24 h. Tissue factor protein was abundant in non-injured coronaries (10 +/- 6 ng microg(-1) total protein, n = 9) and levels were unchanged by injury (13 +/- 11 ng microg(-1), n = 6) or 24-h administration of tissue factor pathway inhibitor (16 +/- 6 ng microg(-1), n = 6). Persistent tissue factor-mediated procoagulant activity may explain the need for prolonged anticoagulation to attenuate neointimal formation after balloon-induced coronary injury.

Topics: Angioplasty, Balloon, Coronary; Animals; Blood Coagulation; Coronary Restenosis; Coronary Vessels; Endothelium, Vascular; Factor Xa; Fibrinolytic Agents; Kinetics; Lipoproteins; Male; Models, Animal; Swine; Thrombin; Thromboplastin

Experimental data suggest that tissue factor (TF) may induce neointimal hyperplasia after arterial injury. In this study, we investigated the hypothesis that elevated levels of TF in the circulation contribute to the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA) or stent implantation.. Whole-blood TF procoagulant activity (TF-PCA) was measured using a previously described assay before, at 3 hours after, and at 24 hours after the intervention in 61 patients with stable angina undergoing PTCA (n=20) or stent implantation (n=41). Coronary angiography was performed 4 to 6 months after the intervention, and luminal narrowing > or =50% was defined as restenosis. Whole-blood TF-PCA levels did not correlate with intracellular monocyte tumor necrosis factor-alpha expression, a marker of activation of these cells. Baseline levels and time course of whole-blood TF-PCA after the intervention were compared in patients who did or did not subsequently develop restenosis. Whole-blood TF-PCA levels did not change significantly in the 24 hours after either intervention. However, in both the PTCA and stent groups, initial TF-PCA was significantly higher in patients who subsequently developed restenosis (P=0.018 and 0.039 compared with those who did not develop restenosis for PTCA and stent groups, respectively).. Higher baseline values of whole-blood TF-PCA may be a predictor of restenosis after PTCA and stent implantation.

Topics: Angina Pectoris; Angioplasty, Balloon, Coronary; Biomarkers; Coronary Restenosis; Female; Humans; Male; Middle Aged; Monocytes; Prognosis; Risk Factors; Stents; Thromboplastin; Tumor Necrosis Factor-alpha

Restenosis is a serious complication of coronary angioplasty that involves the proliferation and migration of vascular smooth muscle cells (VSMCs) from the media to the intima, synthesis of extracellular matrix, and remodeling. We have previously demonstrated that tissue factor-targeted nanoparticles can penetrate and bind stretch-activated vascular smooth muscles in the media after balloon injury. In the present study, the concept of VSMC-targeted nanoparticles as a drug-delivery platform for the prevention of restenosis after angioplasty is studied.. Tissue factor-targeted nanoparticles containing doxorubicin or paclitaxel at 0, 0.2, or 2.0 mole% of the outer lipid layer were targeted for 30 minutes to VSMCs and significantly inhibited their proliferation in culture over the next 3 days. Targeting of the nanoparticles to VSMC surface epitopes significantly increased nanoparticle antiproliferative effectiveness, particularly for paclitaxel. In vitro dissolution studies revealed that nanoparticle drug release persisted over one week. Targeted antiproliferative results were dependent on the hydrophobic nature of the drug and noncovalent interactions with other surfactant components. Molecular imaging of nanoparticles adherent to the VSMC was demonstrated with high-resolution T1-weighted MRI at 4.7T. MRI 19F spectroscopy of the nanoparticle core provided a quantifiable approach for noninvasive dosimetry of targeted drug payloads.. These data suggest that targeted paramagnetic nanoparticles may provide a novel, MRI-visualizable, and quantifiable drug delivery system for the prevention of restenosis after angioplasty.

Topics: Animals; Antibodies; Antineoplastic Agents, Phytogenic; Cell Count; Cell Division; Cell Membrane; Cells, Cultured; Contrast Media; Coronary Restenosis; Delayed-Action Preparations; Dose-Response Relationship, Drug; Doxorubicin; Drug Carriers; Drug Delivery Systems; Fluorine Compounds; Fluorocarbons; Gadolinium DTPA; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Muscle, Smooth, Vascular; Oleic Acid; Oleic Acids; Paclitaxel; Particle Size; Swine; Thromboplastin