title: Growth factor-mediated reversal of senescent dysfunction of ischemia-induced cardioprotection.
abstract: Based on the role of tumor necrosis factor-alpha (TNF-alpha) in ischemic preconditioning (IPC) and the age-associated loss of both TNF-alpha-induced platelet-derived growth factor-AB (PDGF-AB)-mediated cardioprotection and IPC-mediated cardioprotection, we hypothesized that targeting of PDGF-AB-based pathways would restore cardioprotection by IPC in the aging heart. To study this, IPC was induced in 4- and 24-mo-old F344 rats. Sections of young hearts isolated 1 day post-IPC revealed increased TNF-alpha compared with controls. In old rats, TNF-alpha was higher at baseline than IPC young rats and was not significantly altered after IPC. Treatment of old rats with PDGF-AB with vascular endothelial growth factor and angiopoietin-2 (a combination termed PVA), but not PDGF-AB alone, at the time of IPC decreased TNF-alpha. In addition, when compared with young hearts, IPC induced greater apoptosis in the old hearts, which was decreased with PVA treatment but was markedly increased with PDGF-AB. To test the significance of these findings, additional rats underwent permanent coronary ligation 1 day post-IPC. IPC was cardioprotective in young rats [14 days postmyocardial infarction (MI), fractional shortening 29 +/- 6% vs. control MI 17 +/- 4%, P < 0.05; Masson's trichrome stain MI size: 13 +/- 2% vs. control MI 17 +/- 4% left ventricular area (LVA); P < 0.05]. In old rats, however, IPC reduced the post-MI 14-day survival (33% vs. controls 67%; P < 0.05). Treatment of IPC-aging rats with PVA, but not PDGF-AB-alone, reversed IPC-induced mortality (PVA-IPC-MI survival, 88%; PDGF-AB-IPC-MI, 14%) and reduced myocardial injury (fractional shortening: PVA-IPC, 31 +/- 1% vs. control MI, 21 +/- 6%, P < 0.05; MI size: PVA-IPC, 12 +/- 2% vs. control MI, 18 +/- 3% LVA, P < 0.05) and thus demonstrated that PDGF-AB-based pathways can reverse the senescent impairment in IPC-mediated cardioprotection.
authors.affiliation: Department of Medicine, Weill Medical College of Cornell Univ., New York, NY 10021, USA.
authors.forename: Jingang
authors.initials: J
authors.lastname: Zheng
authors.forename: Andrew
authors.initials: A
authors.lastname: Chin
authors.forename: Inga
authors.initials: I
authors.lastname: Duignan
authors.forename: Kyung-Heon
authors.initials: KH
authors.lastname: Won
authors.forename: Mun K
authors.initials: MK
authors.lastname: Hong
authors.forename: Jay M
authors.initials: JM
authors.lastname: Edelberg
mesh_terms: D000375:Aging; D042702:Angiopoietin-2 / Q000494:pharmacology; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004338:Drug Combinations; D017548:Echocardiography, Transesophageal; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology*; D019157:Ischemic Preconditioning, Myocardial; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
chemical_list: D042702:Angiopoietin-2; D051017:Apoptosis Regulatory Proteins; D002316:Cardiotonic Agents; D004338:Drug Combinations; D010982:Platelet-Derived Growth Factor; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; C095477:platelet-derived growth factor AB