Journal
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Volume 306, Issue 10, Pages -Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00090.2014
Keywords
aging; inflammation; angiogenesis; MMP-9; proteomics; extracellular matrix
Funding
- National Institutes of Health San Antonio Cardiovascular Proteomics Center [HHSN-268201000036C (N01-HV-00244), HL-075360, HL-101430, H-L095852, HL-051971, GM-104357]
- Biomedical Laboratory Research and Development Service of the Veterans Affairs Office of Research and Development Award [5I01BX000505]
Ask authors/readers for more resources
Aging is linked to increased matrix metalloproteinase-9 (MMP-9) expression and extracellular matrix turnover, as well as a decline in function of the left ventricle (LV). Previously, we demonstrated that C57BL/6J wild-type (WT) mice > 18 mo of age show impaired diastolic function, which was attenuated by MMP-9 deletion. To evaluate mechanisms that initiate the development of cardiac dysfunction, we compared the LVs of 6-9-and 15-18-mo-old WT and MMP-9 null (Null) mice. All groups showed similar LV function by echocardiography, indicating that dysfunction had not yet developed in the older group. Myocyte nuclei numbers and cross-sectional areas increased in both WT and Null 15-18-mo mice compared with young controls, indicating myocyte hypertrophy. Myocyte hypertrophy leads to an increased oxygen demand, and both WT and Null 15-18-mo mice showed an increase in angiogenic signaling. Plasma proteomic profiling and LV analysis revealed a threefold increase in von Willebrand factor and fivefold increase in vascular endothelial growth factor in WT 15-18-mo mice, which were further elevated in Null mice. In contrast to the upregulation of angiogenic stimulating factors, actual LV vessel numbers increased only in the 15-18-mo Null LV. The 15-18-mo WT showed amplified expression of inflammatory genes related to angiogenesis, including C-C chemokine receptor (CCR) 7, CCR10, interleukin (IL)-1f8, IL-13, and IL-20 (all, P < 0.05), and these increases were blunted by MMP-9 deletion (all, P < 0.05). To measure vascular permeability as an index of endothelial function, we injected mice with FITC-labeled dextran. The 15-18-mo WT LV showed increased vascular permeability compared with young WT controls and 15-18-mo Null mice. Combined, our findings revealed that MMP-9 deletion improves angiogenesis, attenuates inflammation, and prevents vascular leakiness in the setting of cardiac aging.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available