CNR Institute of Clinical Physiology, Pisa, Italy.
J Cell Biochem. 2010 Apr 1;109(5):1033-44. doi: 10.1002/jcb.22486.
Previous studies related impaired myocardial microcirculation in diabetes to oxidative stress and endothelial dysfunction. Thus, this study was aimed to determine the effect of up-regulating pAMPK-pAKT signaling on coronary microvascular reactivity in the isolated heart of diabetic mice. We measured coronary resistance in wild-type and streptozotocin (STZ)-treated mice, during perfusion pressure changes. Glucose, insulin, and adiponectin levels in plasma and superoxide formation, NOx levels and heme oxygenase (HO) activity in myocardial tissue were determined. In addition, the expression of HO-1, 3-nitrotyrosine, pLKB1, pAMPK, pAKT, and peNOS proteins in control and diabetic hearts were measured. Coronary response to changes in perfusion pressure diverged from control in a time-dependent manner following STZ administration. The responses observed at 28 weeks of diabetes (the maximum time examined) were mimicked by L-NAME administration to control animals and were associated with a decrease in serum adiponectin and myocardial pLKB1, pAMPK, pAKT, and pGSK-3 expression. Cobalt protoporphyrin treatment to induce HO-1 expression reversed the microvascular reactivity seen in diabetes towards that of controls. Up-regulation of HO-1 was associated with an increase in adiponectin, pLKB1, pAKT, pAMPK, pGSK-3, and peNOS levels and a decrease in myocardial superoxide and 3-nitrotyrosine levels. In the present study we describe the time course of microvascular functional changes during the development of diabetes and the existence of a unique relationship between the levels of serum adiponectin, pLKB1, pAKT, and pAMPK activation in diabetic hearts. The restoration of microvascular function suggests a new therapeutic approach to even advanced cardiac microvascular derangement in diabetes.
先前的研究表明，糖尿病患者心肌微循环受损与氧化应激和内皮功能障碍有关。因此，本研究旨在确定上调 pAMPK-pAKT 信号对糖尿病小鼠离体心脏冠状动脉微血管反应性的影响。我们在灌注压变化期间测量了野生型和链脲佐菌素（STZ）处理的小鼠的冠状动脉阻力。测定了血浆中的葡萄糖、胰岛素和脂联素水平以及心肌组织中的超氧化物形成、NOx 水平和血红素加氧酶（HO）活性。此外，还测量了对照组和糖尿病心脏中 HO-1、3-硝基酪氨酸、pLKB1、pAMPK、pAKT 和 peNOS 蛋白的表达。STZ 给药后，冠状动脉对灌注压变化的反应随时间呈时间依赖性方式与对照组不同。在糖尿病的 28 周（检查的最长时间）观察到的反应与对照动物中 L-NAME 的给药相似，并与血清脂联素和心肌 pLKB1、pAMPK、pAKT 和 pGSK-3 表达减少有关。钴原卟啉处理诱导 HO-1 表达逆转了糖尿病患者的微血管反应，使其向对照组的反应方向发展。HO-1 的上调与脂联素、pLKB1、pAKT、pAMPK、pGSK-3 和 peNOS 水平的增加以及心肌中超氧化物和 3-硝基酪氨酸水平的降低有关。在本研究中，我们描述了糖尿病发展过程中微血管功能变化的时间过程以及在糖尿病心脏中血清脂联素、pLKB1、pAKT 和 pAMPK 激活水平之间存在的独特关系。微血管功能的恢复表明，即使在糖尿病中存在晚期心脏微血管紊乱，也为其提供了一种新的治疗方法。
