Pro-inflammatory chemokine interleukin-17A may increase venous thrombus resolution by increasing venous thrombus neovascularization

Objectives: The aim of this study was to assess the effect of the pro-inflammatory interleukin (IL)-17A in deep venous thrombosis (DVT) resolution. Materials and Methods: A total of 45 DVT patients, 30 primary deep venous insufficiencies (DVI) patients, and 18 healthy volunteers were divided into three groups: (a) Control group, (b) DVT group, and (c) DVI group. The venous blood samples of the lower extremity with DVT were collected to evaluate the expression of IL-17A in plasma. Samples of superficial venous thrombus and superficial vein without thrombosis were collected to evaluate the expression of IL-17A in tissue. Male C57/BL mice DVT model was established and was randomly divided into five groups: (1) Control group, no treatment or surgical intervention; (2) Sham group, no treatment and sham operation; (3) DVT group, each mouse intravenous (iv) injected with phosphate-buffered saline (PBS); (4) IL-17A group, each mouse was iv injected with IL-17A; and (5) IL-17A-neutralizing antibody (NA) group, each mouse was iv injected with IL17A NA. Inferior vena cava (IVC) with thrombi were collected to measure their length and weight and analysis CD31(+) endothelial cells in thrombus of internal cerebral vein. Results: Western blot suggested that the expression of IL-17A in superficial vein with thrombosis was higher than superficial vein without thrombosis from human samples (P < 0.05). Comparing the plasma IL-17A levels in human samples, it was found that the expression of IL-17A in DVT and DVI groups was higher than those control group (P < 0.05). In C57/BL mice DVT model, immunofluorescence showed that CD31(+) endothelial cells in thrombus in IL-17A intervention group were more than those in other groups (P < 0.05). The weight of IVC with thrombi in IL-17A intervention group were less than those in other groups (P < 0.05), however, without statistical difference compared with the DVT group and IL-17A-NA group. Conclusions: Venous thrombus neovascularization can be increased by pro-inflammatory chemokine IL-17A but do not appear to decrease thrombus size.