Reply to the Editor

Abstract

We thank Gokalp and colleagues for their interest in our study.1Hu Y. Sun Q. Li Z. Chen J. Shen C. Song Y. et al.High basal level of autophagy in high-altitude residents attenuates myocardial ischemia-reperfusion injury.J Thorac Cardiovasc Surg. 2014; 148: 1674-1680Google Scholar By comparing myocardial ischemia-reperfusion injury of patients at different altitude, we found that patients living at a high altitude with congenital heart disease resisted ischemia–reperfusion injury during cardiac surgery better than did those living at a low altitude. We proposed that the effect of increased tolerance to myocardial ischemia was possibly achieved through elevated basal autophagy induced by chronic hypoxia, which may be different from preconditioning with acute intermittent ischemia or hypoxia. Acute ischemic preconditioning and chronic hypoxia can protect organs from the ensuing ischemia, whereas ischemia itself produces both local and remote injury.2Blaisdell F.W. The pathophysiology of skeletal muscle ischemia and the reperfusion syndrome: a review.Cardiovasc Surg. 2002; 10: 620-630Crossref PubMed Scopus (314) Google Scholar With respect to the remote organ damage induced by ischemia, there are two common classic models: ischemia of extremity3Gokalp O. Yurekli I. Kiray M. Bagriyanik A. Yetkin U. Yurekli B.S. et al.Assessment of protective effects of pheniramine maleate on reperfusion injury in lung after distant organ ischemia: a rat model.Vasc Endovascular Surg. 2013; 47: 219-224Crossref PubMed Scopus (11) Google Scholar, 4Yürekli I. Gökalp O. Kiray M. Gökalp G. Ergünes K. Salman E. et al.Effect of pheniramine maleate on reperfusion injury in brain tissue.Med Sci Monit Basic Res. 2013; 19: 285-290Crossref PubMed Scopus (11) Google Scholar and ischemia of mesenteric organs.5Teke Z. Kabay B. Ozden A. Yenisey C. Bir F. Demirkan N.C. et al.Effects of tempol, a membrane-permeable radical scavenger, on local and remote organ injuries caused by intestinal ischemia/reperfusion in rats.J Surg Res. 2008; 149: 259-271Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar, 6Shen J. Fu G. Jiang L. Xu J. Li L. Fu G. Effect of dexmedetomidine pretreatment on lung injury following intestinal ischemia-reperfusion.Exp Ther Med. 2013; 6: 1359-1364PubMed Google Scholar The distant crucial organs in which reperfusion injury occurs include the lungs, kidneys, brain, and heart. Although the lungs are regarded as the most vulnerable remote organ injured after intestinal or extremity ischemia and reperfusion, it seems that few studies have compared injuries to distant tissues and organs induced by ischemic insult to different organs. Relative to ischemia of the extremities, ischemia of mesenteric organs is more critical problem in a sense. In addition to the release of inflammatory mediators from ischemic tissue (such as complement, histamine, interleukin, oxygen free radicals, platelet activating factor, thromboxane, tumor necrosis factor, and so on), ischemia and reperfusion of mesenteric organs may cause gut barrier disruption and endotoxin entry into the circulation, leading to severe systemic inflammation and eventually multiple organ failure.7Matsuo S. Yang W.L. Aziz M. Jacob A. Wang P. Cyclic arginine-glycine-aspartate attenuates acute lung injury in mice after intestinal ischemia/reperfusion.Crit Care. 2013; 17: R19Crossref PubMed Scopus (30) Google Scholar No matter in which organ, the severity of local and remote injury induced by ischemia and reperfusion certainly depends on the mass and duration of the ischemia. The distance of the two organs or tissues seems to have little impact. We are grateful for the opportunity to discuss these important issues with you, and we look forward to further advances in ischemia–reperfusion injury. In distant organ ischemia–reperfusion model, which organ's ischemia will yield more injury?The Journal of Thoracic and Cardiovascular SurgeryVol. 148Issue 4PreviewWe sincerely appreciate the authors of this study.1 In recent published data, ischemia–reperfusion models have been very popular and widely studied. Especially in these experimental studies, one can create ischemia and examine the very same tissue or examine a distant organ apart from the ischemic one. The basic idea in the distant organ ischemia–reperfusion studies has been that reperfusion has its own systemic effects. Many examples for this type of study have been published. The investigators have sometimes examined distant organs such as the brain and lungs after ischemia of a lower extremity,2,3 and sometimes they have examined the lungs after ischemia of mesenteric organs. Full-Text PDF Open Archive