Pericytes promote angiogenesis at the early stage of wound healing

Abstract

Recently, more and more attention has been focused on pericytes as a target of anti‐angiogenic therapy. In this study, we sought to determine whether they exist at the early stage of angiogenesis, and if they existed, determine how they function at this stage during wound healing. In wound tissue, NG2 proteoglycan and desmin immunoreactive pericytes were closely associated with newly forming blood vessels that contained endothelia with BrdU incorporated proliferative cell nuclei. These pericytes co‐expressed vascular endothelial growth factor ‐A (VEGF‐A). Association of pericytes on the migrating/sprouting endothelia with mitotic figure was also observed with transmission electron microscopy. Phenotypically, the pericytes in wound tissues had larger cell bodies and more euchromatic nuclei than the pericytes in normal vasculature, and expressed alpha smooth muscle actin in general, which is unusual phenomenon especially in normal capillary pericytes. These observations together indicate that the activated state of pericytes is essential for the angiogenesis at the early stage of wound healing.We conclude that pericytes do exist at the early stage of the angiogenesis during wound healing to induce proliferation of endothelia and to guide their migration/sprouting via VEGF‐A secretion, though the generally accepted view suggests the absence or disappearance of pericytes at this stage of angiogenesis.