Abstract 1366: Effects of Hs-CRP and Hyperglycemia on Tissue Factor Isoform Expression and Procoagulant Activity in Diabetes Type-2
Individuals with chronically elevated glucose, most patients with type-2 diabetes, have increased inflammation (hs-CRP levels) and accelerated atherosclerosis, associated with acute vascular events. Up to date, it is not known whether hs-CRP or elevated glucose alter the expression and pre-mRNA splicing of tissue factor (TF), the primary initiator of blood coagulation. We have tested the hypothesis that hs-CRP and hyperglycemia singly or combined may increase tissue factor isoform expression. First, we determined changes in tissue factor isoform expression in whole blood and procoagulant activity (PCA) in human monocytic cells obtained from healthy volunteers (controls, n=20) and insulin-treated patients with type-2 diabetes (n=60). TF m-RNA was quantified for the full-length and soluble isoform by real-time PCR. To assess the impact of hs-CRP on TF, the patients were divided into two groups according to their hs-CRP (hs-CRP>0.3 mg/dl or <0.3 mg/dl). Secondarily, PMN cells were isolated and exposed to hs-CRP (100 μg/ml) and/or glucose (50 and 100 mmol/l) and TF PCA was determined post 24h. TF PCA was significantly increased in diabetic patients with increased hs-CRP compared to those with normal hs-CRP (675±61 vs. 329±71 Units (U), p<0.001). Analysis of TF isoform expression revealed the soluble TF isoform to be increased in diabetic patients with increased hs-CRP (for asTF/GAPDH ratio 6.86x10^5±1.06x10^5 vs. 1.04x10^5 ±2.78x10^6, p<0.001). No differences were found in the full-length isoform mRNA between both patient groups. The soluble TF isoform, TF PCA and antigen level were increased in the whole diabetes groups compared to the healthy controls (p<0.001, respectively). To test whether hs-CRP directly induced TF expression, PMN cells were stimulated with hs-CRP. Combined stimulation with hs-CRP and glucose increased tissue factor PCA up to 7 fold (p<0.001 vs. non-stimulated controls). We conclude that hs-CRP in combination with hyperglycemia induces a prothrombotic state in patients with diabetes through the induction of the procoagulant TF in monocytes. The soluble TF isoform may be a suitable marker for the identification of patients with diabetes that exhibit an increased thrombotic risk.