|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Medicine, University of Tennessee, Memphis, TN, USA
* To whom correspondence should be addressed. E-mail: yasun{at}utmem.edu.
Chronic elevation of circulating angiotensin (Ang)II is associated to cardiac remodeling in patients with hypertension and heart failure. The underlying mechanisms, however, are not completely defined. Herein, we studied AngII-induced molecular and cellular events in the rat heart as well as their links to the redox state. We also addressed the potential contribution of aldosterone (ALDO) on AngII-induced cardiac remodeling. In AngII treated rats and compared to controls, we found: 1) the expression of proinflammatory/profibrogenic mediators was significantly increased in the perivascular space and at the sites of microscopic injury in both ventricles; 2) macrophages and myofibroblasts were primary repairing cells at these sites, together with increased fibrillar collagen volume; 3) apoptotic macrophages and myofibroblasts were evident at the same sites; 4) NADPH oxidase (gp91phox) was significantly enhanced at the these regions and primarily expressed by macrophages, while superoxide dismutase (SOD) and catalase levels remained unchanged; 5) plasma 8-isoprostane levels were significantly increased; and 6) blood pressure was significantly elevated. Losatan treatment completely prevented cardiac oxidative stress as well as molecular/cellular responses and normalized blood pressure. Spironolactone treatment partially suppressed the cardiac inflammatory/fibrogenic responses and redox state. Thus, chronic elevation of circulating AngII is accompanied by a proinflammatory/profibrogenic phenotype involving vascular and myocardial remodeling in both ventricles. Enhanced reactive oxygen species production at these sites and increased plasma 8-isoprostane indicate the involvement of oxidative stress in AngII-induced cardiac injury. ALDO contributes, in part, AngII-induced cardiac molecular and cellular responses.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |