Huang Y, Hong H, Li M, Liu J, Jiang C, Zhang H, Ye L, Zheng J. Age-Dependent Oxidative DNA Damage Does Not Correlate with Reduced Proliferation of Cardiomyocytes in Humans.
PLoS One 2017;
12:e0170351. [PMID:
28099512 PMCID:
PMC5242470 DOI:
10.1371/journal.pone.0170351]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 01/03/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND
Postnatal human cardiomyocyte proliferation declines rapidly with age, which has been suggested to be correlated with increases in oxidative DNA damage in mice and plays an important role in regulating cardiomyocyte proliferation. However, the relationship between oxidative DNA damage and age in humans is unclear.
METHODS
Sixty right ventricular outflow myocardial tissue specimens were obtained from ventricular septal defect infant patients during routine congenital cardiac surgery. These specimens were divided into three groups based on age: group A (age 0-6 months), group B (age, 7-12 months), and group C (>12 months). Each tissue specimen was subjected to DNA extraction, RNA extraction, and immunofluorescence.
RESULTS
Immunofluorescence and qRT-PCR analysis revealed that DNA damage markers-mitochondrial DNA copy number, oxoguanine 8, and phosphorylated ataxia telangiectasia mutated-were highest in Group B. However immunofluorescence and qRT-PCR demonstrated that two cell proliferation markers, Ki67 and cyclin D2, were decreased with age. In addition, wheat germ agglutinin-staining indicated that the average size of cardiomyocytes increased with age.
CONCLUSIONS
Oxidative DNA damage of cardiomyocytes was not correlated positively with age in human beings. Oxidative DNA damage is unable to fully explain the reduced proliferation of human cardiomyocytes.
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