Title

Mechanisms of myocardial ischemic preconditioning are age related: PKC-epsilon does not play a requisite role in old rabbits

UMMS Affiliation

Department of Emergency Medicine; Department of Anesthesiology

Publication Date

8-12-2003

Document Type

Article

Subjects

Aging; Alkaloids; Animals; Benzophenanthridines; Blotting, Western; Enzyme Inhibitors; Female; Hemodynamics; *Ischemic Preconditioning, Myocardial; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Phenanthridines; Protein Kinase C; Protein Kinase C-epsilon; Rabbits

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Data obtained from adult cohorts have implicated activation/translocation of protein kinase C (PKC)-epsilon as an important cellular mediator of myocardial infarct size reduction with ischemic preconditioning (PC). Age-related alterations in cellular signaling may, however, confound the extrapolation of mechanistic insight derived from adults to the aging population, the specific subset in which cardioprotection is undoubtedly most relevant. Accordingly, our aim was to investigate the role of PKC-epsilon as a mediator of infarct size reduction with PC in old vs. adult rabbits. In protocol 1, we assessed the effect of PKC-epsilon translocation inhibitor peptide (PKC-epsilon-TIP) and the pan-PKC inhibitor chelerythrine on infarct size reduction with PC in adult and approximately 4-yr-old rabbits, a population previously shown to exhibit definitive hallmarks of cardiovascular aging. Rabbits received 5 min of PC ischemia or a matched control period followed by 30 min of coronary artery occlusion and 3 h of reperfusion, with infarct size (delineated by tetrazolium staining) serving as the primary endpoint. In protocol 2, we obtained insight (by Western immunoblotting) into the subcellular redistribution of PKC-epsilon in response to the 5-min PC stimulus in adult and old rabbits. In adults, infarct size reduction with PC was abrogated by both PKC-epsilon-TIP and chelerythrine. However, in old rabbits, 1). PC-induced cardioprotection was maintained despite inhibitor treatment and 2). brief PC ischemia was not associated with activation/translocation of PKC-epsilon. Thus the mechanisms responsible for PC are age related in the rabbit heart, with no apparent, requisite role of PKC-epsilon in aging animals.

Rights and Permissions

Citation: J Appl Physiol. 2003 Dec;95(6):2563-9. Epub 2003 Aug 8. Link to article on publisher's site

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

Journal of applied physiology (Bethesda, Md. : 1985)

PubMed ID

12909609