The angiogenesis inhibitor, endostatin, does not affect murine cutaneous wound healing

Background. Endostatin is a potent angiogenesis inhibitor, which is currently being used in Phase I trials as an antitumor agent. The purpose of this study was to determine whether endostatin has an effect on wound healing in a murine model. Materials and methods. The function of endostatin was confirmed using a human microvascular endothelial cell (HMVEC) proliferation assay in which cells are treated for 4 days with growth media plus or minus endostatin. Full-thickness incisions were made on the dorsum of athymic nude mice and closed primarily with skin staples. PVA sponges were implanted in some wounds to determine vascular ingrowth. Subsequently, mice were treated with recombinant human endostatin at 20 mg/kg/day or 50 mg/kg/dose BID versus control for a total of 14 days. On Days 2, 4, 8, 12, and 16, three mice per group had serum samples drawn and were sacrificed. Perpendicular breaking strength (N) was determined using an Instron 5540 tensometer. Wound strength was determined by dividing breaking strength by wound area (N/cm²). Vascular density in sponges was determined using CD31 immunohistochemistry. Serum endostatin concentrations were determined using a commercially available ELISA kit. Results. Endostatin caused a significant reduction of endothelial cell proliferation after 4 days compared to media alone (72%, P = 0.031). At all time points tested, there was no statistical difference in the wound- breaking strength between endostatin and control-treated mice at either the low or high dose. Serum endostatin levels were consistently 10-fold higher in endostatin-treated mice than in controls. No differences in vascular density were seen in endostatin versus control-treated mice as determined by CD31 immunohistochemistry of PVA sponges. Conclusion. Therapy with human endostatin does not induce a significant decrease in breaking strength of cutaneous wounds in mice.