|
|
||||||||
1Department of Anatomy and Cell Biology and 2The Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
Submitted 24 March 2006 ; accepted in final form 8 May 2006
Previous studies have not addressed regional differences in adaptive arteriolar growth in the surviving left ventricular (LV) myocardium after infarction in appropriately aged animals, namely middle-aged or older. Accordingly, we examined the adaptive postinfarction growth of arterioles in two distinct regions, i.e., the LV free wall (LVFW) and septum, of middle-aged rats. We induced a myocardial infarction (MI) in 12-mo-old rats to analyze 1) protein expression in VEGF/Flt-1/Flk-1 and angiopoietin (Ang)-1/Ang-2/Tie-2 systems, 2) the arteriolar DNA synthesis, 3) the extent of the arteriolar bed, and 4) the alteration in minimal coronary vascular resistance. In both regions, arteriolar DNA synthesis was activated between days 4 and 7 after MI. Whereas in the LVFW the degree of DNA synthesis declined between days 11 and 14 post-MI, it continued to rise in the septum, and at day 14, the percentage of the arterioles undergoing DNA synthesis was comparable in the LVFW and the septum (9.7 ± 1.6 and 7 ± 2.1%, respectively). Arteriolar DNA synthesis was mainly associated with upregulation of Ang-2 and Tie-2 in both LV regions. Although 4 wk after MI the arteriolar beds in the LVFW and the septum expanded to the size of sham-operated rats, this growth did not compensate for the greater minimal coronary vascular resistance in the former. Thus our findings suggest that 1) the dynamics in adaptive arteriolar growth were similar between the two regions, despite a delay in the septum; and 2) the perfusion deficit in post-MI rats cannot be accounted for by inadequate adaptive growth of arterioles.
myocardial infarction; arteriolar density; minimal coronary vascular resistance; angiogenic growth factors
This article has been cited by other articles:
![]() |
E. I. Dedkov, W. Zheng, L. P. Christensen, R. M. Weiss, F. Mahlberg-Gaudin, and R. J. Tomanek Preservation of coronary reserve by ivabradine-induced reduction in heart rate in infarcted rats is associated with decrease in perivascular collagen Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H590 - H598. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |