Feuvray D, Lopaschuk G D
Laboratoire de Physiologie Cellulaire, Université Paris, Orsay, France.
Cardiovasc Res. 1997 Apr;34(1):113-20. doi: 10.1016/s0008-6363(97)00037-0.
Controversy exists as to whether the diabetic heart is more or less sensitive to ischemic injury. Although a considerable number of experimental studies have directly determined the effects of ischemia on the diabetic heart, there is still no general agreement as to whether metabolic changes within the myocardium contribute to the severity of ischemic injury. This paper reviews the evidence suggesting that the diabetic heart can actually be less sensitive to an episode of severe ischemia. Possible reasons for this decreased sensitivity to injury are discussed, which include a decreased accumulation of glycolytic products during ischemia (lactate and protons), as well as alterations in the regulation of intracellular pH in the diabetic heart. Based on existing studies, we suggest that although impaired glucose metabolism in the diabetic heart contributes to injury in hypoxic hearts or in hearts subjected to low-flow ischemia, diabetes-induced decreases in glycolysis can actually be beneficial to the diabetic heart during and following a severe ischemic episode. A decreased clearance of protons via the Na+/H+ exchanger may also contribute to the decreased sensitivity to ischemic injury in the diabetic heart.
关于糖尿病心脏对缺血性损伤的敏感性是更高还是更低，目前存在争议。尽管大量实验研究已直接确定了缺血对糖尿病心脏的影响，但对于心肌内的代谢变化是否会导致缺血性损伤的严重程度，仍未达成普遍共识。本文回顾了相关证据，表明糖尿病心脏实际上可能对严重缺血发作的敏感性较低。文中讨论了这种对损伤敏感性降低的可能原因，包括缺血期间糖酵解产物（乳酸和质子）积累减少，以及糖尿病心脏细胞内pH调节的改变。基于现有研究，我们认为，尽管糖尿病心脏中受损的葡萄糖代谢会导致缺氧心脏或低流量缺血心脏的损伤，但糖尿病引起的糖酵解减少实际上在严重缺血发作期间及之后可能对糖尿病心脏有益。通过Na+/H+交换体的质子清除减少也可能导致糖尿病心脏对缺血性损伤的敏感性降低。
