Age-associated impairment in TNF-alpha cardioprotection from myocardial infarction.
Age-associated dysfunction in cardiac microvascular endothelial cells with impaired induction of cardioprotective platelet-derived growth factor (PDGF)-dependent pathways suggests that alterations in critical vascular receptor(s) may contribute to the increased severity of cardiovascular pathology in older persons. In vivo murine phage-display peptide library biopanning revealed a senescent decrease in cardiac microvascular binding of phage epitopes homologous to tumor necrosis factor-alpha (TNF-alpha), suggesting that its receptor(s) may be downregulated in older cardiac endothelial cells. Immunostaining demonstrated that TNF-receptor 1 (TNF-R1) density was significantly lower in the subendocardial endothelium of the aging murine heart. Functional studies confirmed the senescent dysregulation of TNF-alpha receptor pathways, demonstrating that TNF-alpha induced PDGF-B expression in cardiac microvascular endothelial cells of 4-mo-old, but not 24-mo-old, rats. Moreover, TNF-alpha mediated cardioprotective pathways were impaired in the aging heart. In young rat hearts, injection of TNF-alpha significantly reduced the extent of myocardial injury after coronary ligation: TNF-alpha, 7.9 +/- 1.9% left ventricular injury (n = 4) versus PBS, 16.2 +/- 7.9% (n = 10; P < 0.05). The addition of PDGF-AB did not augment the cardioprotective action of TNF-alpha. In myocardial infarctions of older hearts, however, TNF-alpha induced significant postcoronary occlusion mortality (TNF-alpha 80% vs. PBS 0%; n = 10 each, P < 0.05) that was reversed by the coadministration of PDGF-AB. Overall, these studies demonstrate that aging-associated alterations in TNF-alpha receptor cardiac microvascular pathways may contribute to the increased cardiovasular pathology of the aging heart. Strategies targeted at restoring TNF-alpha receptor-mediated expression of PDGF-B may improve cardiac microvascular function and provide novel approaches for treatment and possible prevention of cardiovascular disease in older individuals.
Cai
Dongqing
D
Department of Medicine, Weill Medical College of Cornell University, 520 East 70th Street, A352, New York, NY 10021, USA.
Xaymardan
Munira
M
Holm
Jacquelyne M
JM
Zheng
Jingang
J
Kizer
Jorge R
JR
Edelberg
Jay M
JM
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000077214:Becaplermin; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D019151:Peptide Library; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D015703:Antigens, CD; D019151:Peptide Library; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; C095477:platelet-derived growth factor AB; D000077214:Becaplermin