Development of progressive aortic vasculopathy in a rat model of aging

1 Department of Surgery, Indiana University School of Medicine, 2 Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 3 Indiana Center for Vascular Biology and Medicine, 4 Division of Experimental Pathology, Methodist Research Institute/Clarian Health Partners, Inc., 5 Department of Nephrology, Indiana University School of Medicine, and 6 Departments of Medicine and Biochemistry and Molecular Biology, Indiana University School of Medicine, and Department of Veterans Affairs, Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana Submitted 30 March 2007 ; accepted in final form 11 September 2007 Recent studies have established that age is the major risk factor for vascular disease. Numerous aberrant changes occur in vascular structure and function during aging, and animal models are the primary means to determine the underlying mechanisms of age-mediated vascular pathology. The Fischer 344/Brown Norway F1 hybrid (F344xBN) rat thoracic aorta has been shown to display age-related pathology similar to what occurs in humans. This study utilized the F344xBN rat aorta and both morphometric and global gene expression analyses to identify appropriate time points to study vascular aging and to identify molecules associated with the development and progression of vascular pathology. In contrast to some previous studies that indicated age-related abrupt changes, a progressive increase in intimal and medial thickness, as well as smooth muscle cell-containing intimal protrusions, was observed in thoracic aorta. This structural vascular pathology was associated with a progressive, but nonlinear, increase in global differential gene expression. Gene products with altered mRNA and protein expression included inflammation-related molecules: specifically, the adhesion molecules ICAM-1 and VCAM-1 and the bone morphogenic proteins osteopontin and bone sialoprotein-1. Intimal-associated macrophages were found to increase significantly in number with age. Both systemic and tissue markers of oxidant stress, serum 8-isoprostane and 3-nitrotyrosine, respectively, were also found to increase during aging. The results demonstrate that major structural abnormalities and altered gene expression develop after 6 mo and that the progressive pathological development is associated with increased inflammation and oxidant stress. arterial remodeling; inflammation; microarray; oxidative stress Address for reprint requests and other cor