Expression of Endothelial Cell Adhesion Molecules in Neovascularized Tissue

Abstract

Recent studies indicate that endothelial cells of newly formed blood vessels are activated and exhibit a distinct phenotype that may influence the responses of these microvessels to an inflammatory stimulus. The objective of this study was to compare the basal and cytokine-stimulated expression of endothelial cell adhesion molecules in neovascularized tissue to normal (nonproliferating) vascular beds. The expression of P- and E-selectin. VCAM-1, ICAM-1, ICAM-2, and PECAM-1 was measured, using the dual radiolabeled mAb technique, in subcutaneously implanted (for 10-15 days) polyurethane sponges, skin, heart, lung, and intestine of male C57BL/6 mlice (background). Basal values of PECAM-1 and ICAM-2 revealed a low vascular density in the implanted sponge matrices that is comparable to skin. When normalized for vascular surface area (PECAM-1 or ICAM-1 expression), the basal level of E- and P-selectin expression was highest in neovascularized sponge and skin. TNF-alpha elicited an increased expression of all endothelial CAMs, except PECAM-1 and ICAM-2, but the responses were blunted in sponge and skin, relative to other vascular beds. These findings indicate that endothelial cells in newly formed blood vessels exhibit a pattern of basal and cytokine-induced expression of certain adhesion glycoproteins that is similar to nonproliferating cutaneous vessels.