Hazarika Surovi, Dokun Ayotunde O, Li Yongjun, Popel Aleksander S, Kontos Christopher D, Annex Brian H
Division of Cardiology, Duke University and Durham VA Medical Center, Durham, NC 27710, USA.
Circ Res. 2007 Oct 26;101(9):948-56. doi: 10.1161/CIRCRESAHA.107.160630. Epub 2007 Sep 6.
Deficient angiogenesis after ischemia may contribute to worse outcomes of peripheral arterial disease in patients with diabetes mellitus (DM). Vascular endothelial growth factor (VEGF) and its receptors promote angiogenesis. We hypothesized that in peripheral arterial disease, maladaptive changes in VEGF ligand/receptor expression could account for impaired angiogenesis in DM. Skeletal muscle from diet-induced, type 2 diabetic (DM) and age-matched normal chow (NC)-fed mice was collected at baseline and 3 and 10 days after hindlimb ischemia and analyzed for expression of VEGF (n=10 per group), full-length VEGF receptor (VEGFR)-1, soluble VEGFR-1, and markers of downstream VEGF signaling (n=20 per group) using ELISA, reverse transcriptase-polymerase chain reaction, and Western blots. In the absence of ischemia, DM mice had increased VEGF (NC versus DM: 26.6+/-2.6 versus 53.5+/-8.8 pg/mg protein; P<0.05), decreased soluble and membrane-bound VEGFR-1 (NC versus DM: 1.44+/-0.30 versus 0.85+/-0.08 and 1.03+/-0.10 versus 0.72+/-0.10, respectively; P<0.05), decreased phospho-AKT/AKT and phospho-endothelial NO synthase/endothelial NO synthase (NC versus DM: 0.76+/-0.2 versus 0.38+/-0.1 and 0.36+/-0.06 versus 0.25+/-0.04, respectively; P<0.05), and no change in VEGFR-2. After ischemia, both DM and NC had comparable increases in VEGF-A. VEGFR-1 and soluble VEGFR-1 expression increased in both groups, but the fold increase was significantly greater in DM. These data demonstrate that soluble VEGFR-1, an angiogenesis inhibitor, is regulated in skeletal muscle by type 2 DM and ischemia. In the absence of ischemia, despite reductions in both soluble VEGFR-1 and VEGFR-1, VEGF ligand signaling is lower in DM compared with controls. After ischemia, maladaptive upregulation of these receptors further reduces the capacity of VEGF to induce an angiogenic response, which may provide a novel target for therapy.
缺血后血管生成不足可能导致糖尿病（DM）患者外周动脉疾病的预后更差。血管内皮生长因子（VEGF）及其受体可促进血管生成。我们推测，在外周动脉疾病中，VEGF配体/受体表达的适应性改变可能是DM中血管生成受损的原因。在基线、后肢缺血后3天和10天，收集饮食诱导的2型糖尿病（DM）小鼠和年龄匹配的正常饮食（NC）喂养小鼠的骨骼肌，使用酶联免疫吸附测定、逆转录-聚合酶链反应和蛋白质印迹法分析VEGF（每组n = 10）、全长VEGF受体（VEGFR）-1、可溶性VEGFR-1以及VEGF下游信号标志物（每组n = 20）的表达。在没有缺血的情况下，DM小鼠的VEGF增加（NC组与DM组：26.6±2.6对53.5±8.8 pg/mg蛋白质；P<0.05），可溶性和膜结合的VEGFR-1减少（NC组与DM组：分别为1.44±0.30对0.85±0.08和1.03±0.10对0.72±0.10；P<0.05），磷酸化AKT/AKT和磷酸化内皮型一氧化氮合酶/内皮型一氧化氮合酶减少（NC组与DM组：分别为0.76±0.2对0.38±0.1和0.36±0.06对0.25±0.04；P<0.05），而VEGFR-2无变化。缺血后，DM组和NC组的VEGF-A均有相当程度的增加。两组的VEGFR-1和可溶性VEGFR-1表达均增加，但DM组的增加倍数明显更大。这些数据表明，作为血管生成抑制剂的可溶性VEGFR-1在骨骼肌中受2型糖尿病和缺血的调节。在没有缺血的情况下，尽管可溶性VEGFR-1和VEGFR-1均减少，但与对照组相比，DM组的VEGF配体信号更低。缺血后，这些受体的适应性上调进一步降低了VEGF诱导血管生成反应的能力，这可能为治疗提供一个新的靶点。
