Cardiovascular Division, Hospital of University of Pennsylvania and Cardiovascular Institute, University of Pennsylvania 19104, USA.
Am J Physiol Heart Circ Physiol. 2010 Sep;299(3):H699-706. doi: 10.1152/ajpheart.00071.2010. Epub 2010 Jul 2.
Atherosclerosis is an inflammatory process leading to enhanced cellular proliferation, apoptosis, and vasa vasorum (VV) neovascularization. While both diabetes mellitus (DM) and hypercholesterolemia (HC) predispose to atherosclerosis, the precise interaction of these risk factors is unclear. Akt is a central node in signaling pathways important for inflammation, and we hypothesized that DM/HC would lead to aberrant Akt signaling and advanced, complex atherosclerosis. DM was induced in pigs by streptozotocin and HC by a high-fat diet. Animals were randomized to control (non-DM, non-HC), DM only, HC only, and DM/HC groups. Coronary artery homogenates were analyzed by immunoblotting for proteins involved in the Akt pathway, including phosphorylated (p)-Akt (Ser473), p-GSK-3beta (Ser9), activated NF-kappaB p65, and VEGF. Immunohistochemical staining for Ki67 (cell proliferation), terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) (apoptosis), and von Willebrand factor (vWF) (neovascularization) was performed. Neovascularization was visualized with micro-computerized tomography (CT). Only DM/HC animals developed advanced atherosclerosis and showed decreased p-Akt (Ser473) and p-GSK-3beta (Ser9) levels (P < 0.01 and P < 0.05, respectively). DM/HC arteries demonstrated increased cellular proliferation (P < 0.001), apoptosis (P < 0.01), and activation of NF-kappaB p65 (P < 0.05). Induction of DM/HC also resulted in significant VV neovascularization by enhanced VEGF expression (P < 0.05), increased vWF staining (P < 0.01), and increased density by micro-CT. In conclusion, DM and HC synergistically resulted in complex atherosclerosis associated with attenuated p-Akt (Ser473) levels. Aberrant Akt signaling correlated with increased inflammation, cellular proliferation, apoptosis, and VV neovascularization. Our results revealed a synergistic effect of DM and HC in triggering abnormal Akt signaling, resulting in advanced atherosclerosis.
动脉粥样硬化是一种炎症过程，导致细胞增殖、凋亡和血管生成（VV）新生血管化增强。虽然糖尿病（DM）和高胆固醇血症（HC）都会导致动脉粥样硬化，但这些危险因素的确切相互作用尚不清楚。Akt 是信号通路的核心节点，这些信号通路对炎症很重要，我们假设 DM/HC 会导致异常的 Akt 信号转导和更严重、更复杂的动脉粥样硬化。通过链脲佐菌素诱导猪发生 DM，通过高脂肪饮食诱导猪发生 HC。动物随机分为对照组（非 DM，非 HC）、DM 组、HC 组和 DM/HC 组。通过免疫印迹法分析冠状动脉匀浆中参与 Akt 通路的蛋白质，包括磷酸化（p）-Akt（Ser473）、p-GSK-3β（Ser9）、激活的 NF-κB p65 和 VEGF。进行 Ki67（细胞增殖）、末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记（TUNEL）（凋亡）和 von Willebrand 因子（vWF）（新生血管化）的免疫组织化学染色。通过微计算机断层扫描（CT）观察新生血管化。只有 DM/HC 动物才会发展出严重的动脉粥样硬化，并显示出降低的 p-Akt（Ser473）和 p-GSK-3β（Ser9）水平（分别为 P < 0.01 和 P < 0.05）。DM/HC 动脉表现出增加的细胞增殖（P < 0.001）、凋亡（P < 0.01）和 NF-κB p65 的激活（P < 0.05）。DM/HC 的诱导也导致 VEGF 表达增加（P < 0.05）、vWF 染色增加（P < 0.01）和微 CT 密度增加，从而导致显著的 VV 新生血管化。总之，DM 和 HC 协同作用导致与降低的 p-Akt（Ser473）水平相关的复杂动脉粥样硬化。异常的 Akt 信号转导与炎症、细胞增殖、凋亡和 VV 新生血管化增加有关。我们的结果揭示了 DM 和 HC 协同作用触发异常 Akt 信号转导，导致严重动脉粥样硬化的协同效应。
