Department of Gastroenterology and Hepatology, Hepatology Research Unit, Ghent University, Ghent, Belgium.
Department of Endocrinology, Ghent University, Ghent, Belgium.
Hepatology. 2019 Mar;69(3):1087-1104. doi: 10.1002/hep.30294. Epub 2019 Feb 12.
Angiogenesis contributes to the development of nonalcoholic steatohepatitis (NASH) and promotes inflammation, fibrosis, and progression to hepatocellular carcinoma (HCC). Angiopoietin-2 (Ang-2) is a key regulator of angiogenesis. We aimed to investigate the role of Ang-2 and its potential as a therapeutic target in NASH using human samples, in vivo mouse models, and in vitro assays. Serum Ang-2 levels were determined in 104 obese patients undergoing bariatric surgery and concomitant liver biopsy. The effect of the Ang-2/Tie2 receptor inhibiting peptibody L1-10 was evaluated in the methionine-choline deficient (MCD) and streptozotocin-western diet nonalcoholic fatty liver disease mouse models, and in vitro on endothelial cells and bone marrow-derived macrophages. The hepatic vasculature was visualized with µCT scans and scanning electron microscopy of vascular casts. Serum Ang-2 levels were increased in patients with histological NASH compared with patients with simple steatosis and correlated with hepatic CD34 immunoreactivity as a marker of hepatic angiogenesis. Serum and hepatic Ang-2 levels were similarly increased in mice with steatohepatitis. Both preventive and therapeutic L1-10 treatment reduced hepatocyte ballooning and fibrosis in MCD diet-fed mice and was associated with reduced hepatic angiogenesis and normalization of the vascular micro-architecture. Liver-isolated endothelial cells and monocytes from MCD-fed L1-10-treated mice showed reduced expression of leukocyte adhesion and inflammatory markers, respectively, compared with cells from untreated MCD diet-fed mice. In the streptozotocin-western diet model, therapeutic Ang-2 inhibition was able to reverse NASH and attenuate HCC progression. In vitro, L1-10 treatment mitigated increased cytokine production in lipopolysaccharide-stimulated endothelial cells but not in macrophages. Conclusion: Our findings provide evidence for Ang-2 inhibition as a therapeutic strategy to target pathological angiogenesis in NASH.
血管生成有助于非酒精性脂肪性肝炎（NASH）的发展，并促进炎症、纤维化和向肝细胞癌（HCC）的进展。血管生成素-2（Ang-2）是血管生成的关键调节剂。我们旨在使用人体样本、体内小鼠模型和体外测定来研究 Ang-2 的作用及其作为 NASH 治疗靶点的潜力。在接受减肥手术和同时进行肝活检的 104 名肥胖患者中测定血清 Ang-2 水平。在蛋氨酸-胆碱缺乏（MCD）和链脲佐菌素-西方饮食非酒精性脂肪性肝病小鼠模型以及体外在内皮细胞和骨髓来源的巨噬细胞上评估 Ang-2/Tie2 受体抑制肽 L1-10 的作用。使用μCT 扫描和血管铸型的扫描电子显微镜观察肝血管。与单纯脂肪变性患者相比，组织学 NASH 患者的血清 Ang-2 水平升高，并与肝内 CD34 免疫反应性相关，作为肝血管生成的标志物。伴有肝炎的小鼠的血清和肝 Ang-2 水平也同样升高。预防性和治疗性 L1-10 治疗均可减少 MCD 饮食喂养的小鼠中的肝细胞气球样变和纤维化，并且与肝血管生成减少和血管微结构正常化相关。与未治疗的 MCD 饮食喂养的小鼠相比，从 MCD 喂养的 L1-10 治疗的小鼠中分离的肝内皮细胞和单核细胞显示出白细胞黏附和炎症标志物的表达减少。在链脲佐菌素-西方饮食模型中，治疗性 Ang-2 抑制能够逆转 NASH 并减轻 HCC 进展。在体外，L1-10 治疗减轻了脂多糖刺激的内皮细胞而不是巨噬细胞中细胞因子产生的增加。结论：我们的研究结果为 Ang-2 抑制作为 NASH 病理性血管生成的治疗策略提供了证据。
