Su Jun, Lucchesi Pamela A, Gonzalez-Villalobos Romer A, Palen Desiree I, Rezk Bashir M, Suzuki Yasuhiro, Boulares Hamid A, Matrougui Khalid
Department of Pharmacology, Tulane University, 1430 Tulane Ave, New Orleans LA 70112, USA.
Arterioscler Thromb Vasc Biol. 2008 Aug;28(8):1432-8. doi: 10.1161/ATVBAHA.108.167205. Epub 2008 May 15.
Type 2 diabetes is associated with increased advanced glycation end product (AGE) formation and vasculopathy. We hypothesized that AGEs contribute to resistance artery dysfunction.
Type 2 diabetic db(-)/db(-) (diabetic) and nondiabetic db(-)/db(+) (control) mice were treated with the AGE inhibitor (aminoguanidine: 50 mg/Kg/d) for 3 months. Isolated mesenteric resistance arteries (MRAs) were mounted in an arteriograph. Pressure-induced myogenic tone (MT) was increased in diabetic mice but was unaffected by aminoguanidine treatment. Phenylephrine-induced contraction and nitric oxide donor-induced endothelium-independent relaxation were similar in all groups. In diabetic mice, endothelium-dependent relaxation in response to shear-stress or acetylcholine was altered and was associated with reduced eNOS protein and mRNA expression. Aminoguanidine treatment improved endothelial function and restored eNOS expression. AGE formation and hypoxia markers (plasminogen activator inhibitor 1 and Bnip3) were increased in MRA from diabetic mice and normalized with Aminoguanidine. Primary cultured endothelial cells (ECs) isolated from resistance arteries subjected to high glucose for 48 hours showed decreased eNOS expression and phosphorylation in response to calcium ionophore. High glucose decreased antioxidant protein (MnSOD) and increased prooxidant proteins (gp91phox) expression leading to increased oxidative stress generation, as assessed by DHE staining and endothelial NADH/NADPH oxidase activity. The preincubation of ECs with aminoguanidine restored eNOS-phosphorylation and expression as well as the balance between pro- and antioxidant factors induced by high glucose.
We provide evidence of a link between AGEs, oxidative stress, and resistance artery EC dysfunction in type 2 diabetic mice. Thus, AGEs and oxidative stress may be a potential target for overcoming diabetic microvessels complications.
2型糖尿病与晚期糖基化终末产物（AGE）生成增加及血管病变有关。我们推测AGEs会导致阻力动脉功能障碍。
将2型糖尿病db(-)/db(-)（糖尿病）小鼠和非糖尿病db(-)/db(+)（对照）小鼠用AGE抑制剂（氨基胍：50mg/Kg/d）治疗3个月。将分离的肠系膜阻力动脉（MRA）安装在血管造影仪上。糖尿病小鼠中压力诱导的肌源性张力（MT）增加，但不受氨基胍治疗的影响。苯肾上腺素诱导的收缩和一氧化氮供体诱导的非内皮依赖性舒张在所有组中相似。在糖尿病小鼠中，对剪切应力或乙酰胆碱的内皮依赖性舒张发生改变，且与eNOS蛋白和mRNA表达降低有关。氨基胍治疗改善了内皮功能并恢复了eNOS表达。糖尿病小鼠MRA中AGE生成和缺氧标志物（纤溶酶原激活物抑制剂1和Bnip3）增加，用氨基胍可使其正常化。从阻力动脉分离的原代培养内皮细胞（ECs）在高糖环境下培养48小时后，对钙离子载体的反应显示eNOS表达和磷酸化降低。高糖降低了抗氧化蛋白（MnSOD）并增加了促氧化蛋白（gp91phox）的表达，导致氧化应激产生增加，这通过DHE染色和内皮NADH/NADPH氧化酶活性评估。用氨基胍预孵育ECs可恢复eNOS磷酸化和表达以及高糖诱导的促氧化和抗氧化因子之间的平衡。
我们提供了2型糖尿病小鼠中AGEs、氧化应激与阻力动脉内皮细胞功能障碍之间联系的证据。因此，AGEs和氧化应激可能是克服糖尿病微血管并发症的潜在靶点。
