Abstract
Endogenous generation of inflammatory cytokines such as the C-reactive protein (CRP), tumor necorsis factor a (TNFα ), soluble CD 40-L (CD 40-L), monocyte chemotactic protein-1 (MCP-1) and enhanced formation of nitric oxide free radical (NO), significantly contribute to the pathogenesis of malignancy associated vascular and thrombotic disorders. An estimated 78 out of 1000 cancer patients develop symptomatic thrombosis (7.8%). Anticoagulant drugs such as the heparins and oral anticoagulants (warfarin) have been used in these patients for the overall management of cancer associated thrombotic and vascular events with improved clinical outcome. To further understand the pathogenesis of malignancy associated thrombosis and its modulation by a low molecular weight heparin (LMWH), enoxaparin (E) and warfarin (W), plasma samples were retrospectively analyzed from an open label, multidose, active comparator parallel design study in which all patients (n=110) were initially treated with enoxaparin at 1–1.5 mg/kg SC for 5 days. These patients were further subdivided into two groups. The first group continued to receive E whereas the second group received W (INR target 2–3), for up to 12 weeks. Baseline blood samples (BL), 5 day post enoxaparin (IPE) and 4–6 weeks samples from the E and W were analyzed for various inflammatory cytokines and NO. A highly sensitive CRP ELISA based assay (American Diagnostica, Stamford, CT), a sandwich based ELISA method for TNFα , CD 40-L and MCP-1 (R&D Systems, Minneapolis, MN) were used. In addition, tissue factor pathway inhibitor (TFPI) and thrombin activatable fibrinolytic inhibitor (TAFI) antigen levels were measured using commercially available ELISA kits (American Diagnostics, Stamford, CT and Hyphen Research, Paris, France), respectively. The results are summarized in the table below. The initial treatment of all of the cancer patients with thrombosis 1.0–1.5 mg/kg SC for 5 days resulted in a decrease of the circulating CRP, TNFα , CD 40-L and MCP-1 levels. NO levels were also dramatically reduced after this treatment. Increased levels of TFPI were also noted whereas, the TAFI antigen levels were reduced. Patients who were continued on E continued to exhibit reduced levels of most of these inflammatory markers and NO. However, patients treated with W exhibited a rebound increase in most of these markers and NO levels. At the 4–6 weeks time period in the W group the TFPI levels reverted back to normal levels. An increase in the TAFI levels were noted in this group. These results clearly indicate that various inflammatory markers and NO levels are upregulated in cancer patients with thrombosis. E is capable of down regulating these cytokines, however W treatment fails to sustain this down regulation.
Group CRP μg/ml TNF α(pg/ml) CD40-L(pg/ml) MCP-1 (pg/ml) NO M(μ) TFPI(ng/ml) TAFI( %NHP) BL 15.1±1.2 37±10 1208±180 540±60 63±23 74±11 92±14 IPE 9.2±3.4 20±6 590±125 342±82 22±8 151±34 76±12 4–6 weeks E 7.8±2.8 19±2.3 560±87 290±76 20.1±8 168±27 71±10 4–6 weeks W 9.1±2.1 18±2.3 690±79 312±65 25±11 82±15 96±15
Down regulation of peroxisome proliferator-activated receptorγ expression by inflammatory cytokines and its reversal by thiazolidinediones