Inhibition of plaque neovascularization reduces macrophage accumulation and progression of advanced atherosclerosis

TLDR

Plaque angiogenesis drives atheroma growth and may serve as a conduit for leukocyte infiltration, with activated macrophages further stimulating angiogenesis, although the precise functions of plaque capillaries remain unclear. In apolipoprotein E‑deficient mice, vasa vasorum density correlates with inflammatory cell burden, and angiogenesis inhibitors such as angiostatin reduce plaque angiogenesis, macrophage accumulation, and atherosclerosis progression, demonstrating that late‑stage blockade of plaque angiogenesis interrupts the positive feedback loop between angiogenesis and inflammation and may improve plaque stability.

Abstract

Plaque angiogenesis promotes the growth of atheromas, but the functions of plaque capillaries are not fully determined. Neovascularization may act as a conduit for the entry of leukocytes into sites of chronic inflammation. We observe vasa vasorum density correlates highly with the extent of inflammatory cells, not the size of atheromas in apolipoprotein E-deficient mice. We show atherosclerotic aortas contain activities that promote angiogenesis. The angiogenesis inhibitor angiostatin reduces plaque angiogenesis and inhibits atherosclerosis. Macrophages in the plaque and around vasa vasorum are reduced, but we detect no direct effect of angiostatin on monocytes. After angiogenesis blockade in vivo , the angiogenic potential of atherosclerotic tissue is suppressed. Activated macrophages stimulate angiogenesis that can further recruit inflammatory cells and more angiogenesis. Our findings demonstrate that late-stage inhibition of angiogenesis can interrupt this positive feedback cycle. Inhibition of plaque angiogenesis and the secondary reduction of macrophages may have beneficial effects on plaque stability.