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Alterations of arterial physiology in osteopontin-null mice
Daniel L Myers1, Kelley J Harmon, Volkhard Lindner
1Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Dr, Scarborough, ME 04074, USA.
Objective:
In this study, we characterized the effects of an osteopontin (OPN)-null mutation in normal arterial function and remodeling in a murine model.
Methods And Results:
OPN-null mutant mice were compared with wild-type mice before and after carotid artery ligation. Before ligation, OPN-null mice had increased heart rate, lower blood pressure, and increased circulating lymphocytes compared with wild-type mice. OPN-null vessels also demonstrated greater compliance accompanied by a loosely organized collagen network. After carotid artery ligation, significant differences were also found in the remodeling response of OPN-null animals. At 4 days after ligation, leukocyte adhesion/invasion was diminished by 10-fold in OPN-null mice compared with wild-type mice. At 14 days after ligation, the ligated arteries of OPN-null mice had smaller neointimal lesions but greater constrictive remodeling compared with wild-type mice, resulting in similar lumen areas. Continued remodeling resulted in a similar morphological phenotype in both groups at 28 days.
Conclusions:
These data show that endogenous OPN regulates normal vascular physiology and contributes to the vascular remodeling response by regulating vascular compliance and the inflammatory response.
Insights
Osteopontin (OPN) deficiency alters normal arterial function and vascular remodeling. OPN-null mice exhibit distinct physiological and inflammatory responses, impacting vessel compliance and repair after injury.
Area of Science:
- Vascular Biology
- Immunology
- Cardiovascular Physiology
Background:
- Osteopontin (OPN) is a glycoprotein involved in various physiological processes.
- Its role in normal arterial function and vascular remodeling remains incompletely understood.
Purpose of the Study:
- To investigate the impact of an osteopontin (OPN)-null mutation on normal arterial function and vascular remodeling.
- To elucidate the contribution of endogenous OPN to vascular physiology and post-injury repair.
Main Methods:
- Characterization of OPN-null mutant mice and wild-type littermates.
- Assessment of arterial function and remodeling before and after carotid artery ligation.
- Analysis of physiological parameters, including heart rate, blood pressure, and circulating lymphocytes.
Main Results:
- OPN-null mice displayed increased heart rate, lower blood pressure, and elevated lymphocytes compared to wild-type controls.
- OPN-null vessels showed enhanced compliance and a less organized collagen structure.
- Following ligation, OPN-null mice had reduced leukocyte adhesion, smaller neointimal lesions, and greater constrictive remodeling.
Conclusions:
- Endogenous osteopontin plays a crucial role in regulating normal vascular physiology.
- OPN influences vascular compliance and the inflammatory response during vascular remodeling.
- These findings highlight OPN's significance in arterial function and response to injury.