Morphological and immunohistochemical study of perivascular macrophages: Key findings for angiogenesis

Abstract

As a possible target for pro- or anti-angiogenic therapy, the process of angiogenesis has become more widely recognized in disease and is essential in normal growth and development. The current study examined the immunological activities of macrophages during angiogenesis in quail embryos. CD68 was used to identify perivascular macrophages, which also retained expression of some stem cell markers, including CD34 and CD117, and also CD21. The macrophages also expressed vascular endothelial growth factor (VEGF), a key promoter of angiogenesis, and matrix metalloproteinase-9 (MMP-9), which degrades matrix components to facilitate the formation of new blood vessels. The growth factor bone morphogenetic protein (BMP) and platelet-derived growth factor receptor-alpha (PDGF-α), which are often associated with mesenchymal cell recruitment and vascularization, were also expressed in the perivascular macrophages. More recently, studies investigating macrophages have become more prominent due to their proposed effects on endothelial cells. Macrophages are also increasingly considered potential targets for pro- or anti-angiogenic therapies, and this research provides insights into protein expression and roles in angiogenesis.