Improved scar in postburn patients following interferon-α2b treatment is associated with decreased angiogenesis mediated by vascular endothelial cell growth factor

Hypertrophic scar (HTS) after thermal injury is a dermal fibroproliferative disorder, which leads to considerable morbidity. Previous clinical studies from our laboratory have suggested that interferon-alpha 2b (IFN-alpha 2b) improves scar quality as a result of the suppression of fibroblast function. More recently, our work has demonstrated that the improvement of scar in patients with HTS after IFN-alpha 2b treatment may be associated with a decreased number of fibrocytes and/or altered fibrocyte function. In this study, we report that the improvement of HTS after IFN alpha-2b treatment may be associated with a decrease in angiogenesis. Using immunohistochemistry, we demonstrate an increase in angiogenesis in HTS compared to normal skin, and also show an increase in the expression of vascular endothelial cell growth factor (VEGF) in HTS. Subsequently, we demonstrate a significant reduction in angiogenesis in HTS tissue from patients after treatment with systemic IFN-alpha 2b. By using a [3H] thymidine incorporation assay, we demonstrate that IFN-alpha 2b suppresses the proliferation of human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner. In addition, IFN-alpha 2b inhibits VEGF-induced proliferation and tube formation by using HUVECs. All these effects may be a result of the blocking of VEGF receptor expression on endothelial cells by IFN-alpha 2b. Taken together with previous results, the present study suggests that the improvement of scar quality in HTS patients after IFN-alpha 2b treatment may also be associated with decreased angiogenesis in HTS. The current in vitro results may provide some insights into the scar improvement that is seen with systemic IFN-alpha 2b treatment.