Enhanced Angiotensin II-Induced Cardiac and Aortic Remodeling in ACE2 Knockout Mice
| Autor: | Nathan M. Weir, Mahmoud S. Alghamri, Susan B. Gurley, Mark P. Anstadt, Mariana Morris, Khalid M. Elased |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Male
Cardiac function curve Mean arterial pressure medicine.medical_specialty Blood Pressure Peptidyl-Dipeptidase A Mice Heart Rate medicine.artery Internal medicine medicine Animals Pharmacology (medical) Ventricular remodeling Aorta Infusion Pumps Mice Knockout Pharmacology Ejection fraction Ventricular Remodeling business.industry Angiotensin II Hypertrophic cardiomyopathy medicine.disease Mice Inbred C57BL Endocrinology Angiotensin-converting enzyme 2 cardiovascular system Angiotensin-Converting Enzyme 2 Cardiology and Cardiovascular Medicine business hormones hormone substitutes and hormone antagonists |
| Zdroj: | Journal of Cardiovascular Pharmacology and Therapeutics. 18:138-151 |
| ISSN: | 1940-4034 1074-2484 |
| DOI: | 10.1177/1074248412460124 |
| Popis: | Angiotensin-converting enzyme 2 (ACE2) is present in the heart and thought to exert protective functions. We conducted studies in ACE2 deficient mice to determine whether enzyme loss would exacerbate the cardiac and vascular pathological responses to chronic subcutaneous (sc) angiotensin II (Ang II) infusion. Eight-week-old male ACE2 knockout (KO) and wild type (WT) mice were infused with Ang II (1000 ng/kg per min, 4 weeks) using mini-osmotic pumps. Blood pressure (radiotelemetry), cardiac function (echocardiography, echo), cardiac/aortic structure (histology, collagen, and oxidative stress), and vascular inflammation were examined. Before Ang II infusion, ACE2 KO mice showed unaltered cardiac function and blood pressure. After 4 weeks of Ang II infusion, the mean arterial pressure (MAP) increased from 96 ± 2 to 136 ± 17 mm Hg (∼40%) in WT and from 104 ± 5 to 141 ± 13 mm Hg (∼ 35%) in ACE2 KO. While there were no differences in MAP between groups, the ACE2 KO responded differently to the hypertensive stimulus. Echo analysis revealed severe myocardial dysfunction in Ang II-infused ACE2 KO (Ang ACE2 KO). Ejection fraction was lower (39% versus 50%) as was fractional shortening (27% versus 38%) in ACE2 KO versus WT, respectively. Cardiac dysfunction was associated with hypertrophic cardiomyopathy shown by increased left-ventricular wall thickness, average cardiomyocyte cross-sectional area, and heart weight/body weight ratio. Collagen staining in the myocardium and aorta revealed increased collagen in Ang ACE2 KO, suggestive of remodeling. Results also showed enhanced oxidative stress in the myocardium and aorta of Ang ACE2 KO. There was a 3-fold elevation in macrophage inflammatory protein 1α (MIP 1α) in the aorta of ACE2 KO. Studies in the ACE2 KO model reveal the importance of ACE2 in the maladaptive cardiac and aortic responses to Ang II stimulation, seen as enhanced remodeling using physiological, structural, and biochemical markers. Results document a cardio- and vascular-protective role of ACE2 under pathological conditions. |
| Databáze: | OpenAIRE |
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