Fig. 7: Interplay of adventitial cells in angiogenic activation.
From: Bone marrow-independent adventitial macrophage progenitor cells contribute to angiogenesis
In ARA the majority of macrophages arise from resident bone marrow-independent and at least partially yolk sac-independent Ly6c+/Sca-1+ adventitial progenitor cells. VEGF released by macrophages on the one hand induces angiogenetic sprouting by stimulating the differentiation of CD34+ progenitor cells within the adventitial vasculogenic zone into CD31+ endothelial cells. On the other hand, macrophage-derived VEGF potentiates the generation of macrophages via VEGF/VEGFR2 signaling in terms of a feedforward loop thereby maintaining the angiogenic process.
