Response of the Endothelium to the Epicutaneous Application of Leukotriene B4

Abstract

Background: Vascular changes, both endothelial and functional, are crucial events in inflammatory responses. Objectives: To investigate the dynamics of endothelial cell (EC) and functional changes during acute inflammation in an in vivo model of the skin using leukotriene B₄. Methods: EC proliferation, vascular network size, vessel diameter (VD), and hypoxia-inducible factor (HIF)-1α were studied by immunohistochemical CD31/Ki67 double staining and single staining of HIF-1α. Cutaneous perfusion (CP) was assessed using the Twente Optical Perfusion Camera. Results: The initial phase illustrated an increase in VD, Ki67+ EC, and HIF-1α expression and late-phase vascular expansion. The HIF-1α and Ki67+ EC expression was limited. CP and VD were augmented after 24 h. Conclusion: The early phase of inflammation is characterized by EC proliferation and HIF-1α expression. Vascular expansion continues over time. CP and VD are seen in both phases of inflammation. Angiogenesis, vascular network formation, and perfusion are time-dependent processes which are mutually related during inflammation.