Abstract 14958: The Effect of Early Phase of Ischemic Preconditioning on the Leptin Resistant Diabetic Heart
Ischemic Preconditioning (PC) is a powerful cardioprotective phenomenon which has been demonstrated in many healthy species including human beings. However, it is unknown whether this protective effect exists in the leptin resistant diabetic heart. Accordingly, we tested if diabetes abrogates the cardioprotective effect against myocardial infarction by early phase of PC in the ischemia/reperfusion model in vivo in the mouse. All animals were subjected to a 30-min coronary occlusion (O) and 4 h of reperfusion (R). In wild-type (WT, C57BL/6J) mice (group I) infarct size averaged 63.3 ± 2.2 % of the risk region (Figure). In diabetic mice (Leptin resistant, B6.BKS[D]-Leprdb/J [db/db], group III), infarct size was significantly bigger (72.0 ± 3.4 %), indicating that diabetes increases infarct size in the absence of PC (Figure). When WT mice were preconditioned 10 min earlier with six 4-min O/4-min R cycles (group II), infarct size was markedly reduced to 23.6 ± 2.0 %, indicating an early PC effect. In contrast, when diabetic mice were preconditioned by the same protocol, 10 min earlier with six 4-min O/4-min R cycles (group IV), infarct size was not reduced (72.2 ± 5.1 %), indicating the early PC is abrogated in diabetic mice. There was no significant difference in the risk region (Figure) and the heart weight to tibia length ratio among the four groups. In conclusion, diabetes increases infarct size in the naive heart and abrogates the infarct-sparing effect of early PC. This is first study to demonstrate that the early PC fails to protect the (leptin resistant) diabetic heart.
- © 2013 by American Heart Association, Inc.