Abstract 17872: Humoral Transfer of Remote Ischemic Preconditioning’s Protection From Donor Pigs in Vivo to Isolated Recipient Rat Hearts
Objectives: Remote ischemic preconditioning (RIPC), i.e. brief episodes of ischemia/reperfusion in a remote organ prior to prolonged myocardial ischemia/reperfusion, reduces myocardial infarct size. However, it is still unclear how this protective stimulus is transferred from the remote organ to the heart. We have now addressed the transfer of a blood-borne factor from “donor” pigs undergoing either RIPC or placebo to an isolated perfused "recipient" rat heart. Cardioprotection was confirmed in both, donors and recipients, by measuring the infarct size after a prolonged period of ischemia/reperfusion.
Methods: In anesthetized donor pigs, RIPC was induced by 4 cycles of 5/5 min hind limb occlusion/reperfusion. Sixty min after RIPC, arterial blood was collected (n=8) and plasma was separated. Corresponding samples from placebo pigs without RIPC (n=8) were used as control. Twenty min after blood sampling, pigs were subjected to 60 min regional ischemia and 3 h reperfusion. The recipient rat hearts were mounted on a Langendorff apparatus and perfused at 75 mmHg with Krebs-Henseleit-buffer. After stabilization, pig plasma was added in a 1:10 mixture to the perfusate over 8 min before and 5 min after a period of global ischemia (30 min) followed by 2 h reperfusion. Infarct size in pigs and rats was determined by TTC-staining.
Results: With perfusion of placebo plasma, infarct size in the isolated rat hearts was 40±2% (mean ± SE) of the ventricles. Plasma from pigs subjected to RIPC reduced infarct size to 26±1% (p<0.001). The infarct size reduction in isolated rat hearts by perfusion with plasma from pigs subjected to RIPC correlated with the infarct size reduction induced by RIPC in the donor pigs in vivo (r=0.72).
Conclusion: Blood from pigs after an RIPC maneuver in vivo contains a protective humoral factor against infarction which can be transferred to an isolated rat heart model of ischemia/reperfusion in vitro.
- © 2013 by American Heart Association, Inc.