Ischemic preconditioning (IPrec) improves post-ischemic dysfunctions of the myocardium along with activation of protein kinase C isozymes including PKCδ. Moreover, expression of cardio-protective determinants can reduce ischemic damages. Because IPrec is limited in aged hearts, we assessed in an experimental model the impact of aging on PKCδ and selected protective proteins in the preconditioned myocardium from adult (≤55) and older (≥70 years) humans. Adult myocardium showed PKCδ up-regulation after IPrec along with improved post-ischemic contractility. Although there was no functional benefit, PKCδ increased in older myocardium as well. Subsequent mRNA analyses demonstrated that IPrec stabilizes the mRNA expression of protective proteins (Hsp70, Bcl-2/-xL, IAPs) in both aging groups. Moreover, older hearts revealed increase in post-ischemic Hsp90β. Our study indicates, that IPrec conserves the expression of cardio-protective determinants in aged hearts despite limited functional recovery.
