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Aim Vasa vasorum neovascularization is a key feature of atherosclerosis (AS) and is strongly associated with inflammatory infiltration, lipid deposition, intraplaque hemorrhage, and hemosiderin deposit. Here we investigate the effects of Endostar, a strong anti-angiogenic drug, on vasa vasorum neovascularization in the experimental porcine model of early AS. Methods Eighteen adult male Ba-Ma mini pigs were randomized into three groups, with six animals in each group. The pigs in the normal (N) group were fed a normal diet for 18 weeks, without balloon injury surgery. The animals in the atherosclerotic (AS) control and AS＋Endostar groups were fed a hypercholesterolemic diet for 12 weeks after balloon injury surgery; they received either saline or Endostar for an additional six weeks, while continuing the hypercholesterolemic diet. The atherosclerotic abdominal aorta and levels of serum lipids, TNF-alpha, IL-6, and hs-CRP were analyzed at 18 weeks. Results The AS group had a significantly higher body weight and serum lipid concentration levels than the N group (p ＜ 0.05), confirming the success of the hypercholesterolemic diet. However, no statistical differences were noted between the AS and AS＋Endostar groups. Histopathology results revealed that vasa vasorum density and intima-media thickness (IMT) had also increased in the AS group compared with those in the N group (p ＜ 0.05). The Endostar treatment significantly alleviated AS with decreased vasa vasorum density and IMT (AS vs. AS＋Endostar, p ＜ 0.05). Western blot analysis indicated that the expression of VEGF, β-catenin, and TNF-alpha in the atherosclerotic abdominal aorta was considerably reduced by the Endostar treatment. In addition, immunohistochemistry results showed that the angiogenesis markers VEGF and β-catenin were predominately localized in endothelial cells of the adventitial vasa vasorum. The levels of the serum inflammatory markers TNF-alpha, hs-CRP, and IL-6 were markedly higher in the AS group than in the N group (p ＜ 0.05) but showed no marked difference during the Endostar treatment, suggesting that the local inhibition of angiogenesis was not accompanied by a change in serum inflammatory markers and that the inhibitive effect of Endostar on local TNF-alpha expression could be because of the prevention of vasa vasorum neovascularization. Conclusions Our results demonstrated that the Endostar treatment inhibited vasa vasorum neovascularization and AS progression in the experimental porcine model of early AS, supporting the role of vasa vasorum neovascularization in the development of AS and the therapeutic potential of anti-angiogenesis intervention in AS.

Objective: Atherosclerotic plaques and neovascularization play an important role in the course of coronary atherosclerosis. This study evaluated the effect of recombinant endostatin on experimental atherosclerotic plaques and neovascularization in rabbits. Methods: Eighteen healthy male rabbits were divided into three groups: control group, atherosclerotic model group, and recombinant endostatin treated group. The atherosclerotic model was established via a high-cholesterol diet after balloon catheter injury. The subject weights, serum total cholesterol, creatine kinase-myocardial band fraction (CKMB), and matrix metalloproteinase-2 (MMP-2) were measured. Six weeks after treatment, the aortic roots were taken for pathological assay. The thickness ratio of the intima to media was measured by hematoxylin and eosin (HE) staining, and the number of neovessels was measured by immunohistochemistry via monoclonal antibody CD31 staining. Results: The weight, plasma total cholesterol, and CKMB were not significantly different between the atherosclerotic model group and the recombinant endostatin treated group, but much higher than those of the control group (P0.05) in the recombinant endostatin treated group, compared to the atherosclerotic model group. Conclusions: Recombinant endostatin is able to inhibit the growth of neovascularization in the atherosclerotic plaque and the development of plaque.

Endostar, a novel modified recombinant human endostatin, is now widely studied for the treatment of diseases that are characterized or caused by pathological angiogenesis. However, its molecular mechanism remains unclear. In this study, we investigated the effects of Endostar on the Wnt/β-catenin signaling pathway, which has emerged as an important aspect of angiogenesis. We showed that Endostar significantly inhibited the proliferation, migration, invasion, and capillary-like tube formation of human umbilical vascular endothelial cells in a dose-dependent manner. Using a luciferase reporter assay, we also demonstrated that Endostar suppressed β-catenin-dependent T cell factor transcriptional activity in increasing doses. Moreover, we found that Endostar treatment also restricted the stabilized mutant β-catenin-mediated increase in transcriptional activity, suggesting that Endostar exerts its inhibitory influence on Wnt/β-catenin signaling by targeting β-catenin or its downstream molecules. Western blot and immunofluorescence results revealed that Endostar significantly decreased nuclear and total β-catenin levels. Finally, we discovered that Endostar down-regulated cyclin D1 and VEGF, two proteins that are known as the downstream targets of Wnt/β-catenin signaling and that also play important roles in angiogenesis. Our findings suggested that Endostar inhibits angiogenesis and that the downregulation of the Wnt/β-catenin signaling pathway may be involved in the inhibition of angiogenesis by Endostar. These results support the use of Endostar in further clinical applications.