Distinct Patterns of Angiogenesis in Oral and Skin Wounds

Clinical observation suggests that oral mucosal wounds heal faster than skin; however, little is known about the site-specific differences. Since fetal skin wounds heal rapidly, but are less vascular than adult wounds, we hypothesized that less robust wound angiogenesis might be observed in healing oral mucosa. This study investigated angiogenesis in equivalent-size oral and skin murine wounds. Change in wound bed vascularity was significantly lower in oral wounds than in skin. Also, vascular endothelial growth factor (VEGF) levels were less in oral than cutaneous wounds. Because keratinocytes are a prominent source of VEGF in wounds, we compared VEGF production by oral and epidermal keratinocytes in vitro. Significantly higher levels of VEGF protein and mRNA were observed in epidermal keratinocytes than in oral keratinocytes after 18 hrs of hypoxia. This study demonstrates distinct angiogenesis patterns in oral and skin wounds and intrinsic site-specific differences in VEGF production by keratinocytes.