Increased activity of vascular angiotensin converting enzyme
related to atherosclerotic lesions in hyperlipidemic rabbits.
Mitani, Hironobu, Tsutomu Bandoh, Masaaki Kimura, Tetsuya Totsuka, and
Shigehiro Hayashi.
Department of Pharmacology, Sandoz Tsukuba Research Institute,
APStracts 3:0114H, 1996.
The relationship between vascular angiotensin converting enzyme (ACE)
activity in the aorta and atherosclerotic lesions was investigated in
rabbits fed two atherogenic diets, 0.5 and 1.5 % high cholesterol,
for 17 weeks. Tissue ACE activity was assessed by the cleavage rate
of hippuric acid from a synthetic substrate. Total cholesterol,
triglycerides and phospholipids in the serum were significantly
increased by the diet. Vascular ACE activity in the femoral artery,
abdominal aorta and aortic arch was significantly increased (2 to 5
times) by the atherogenic diet in a high cholesterol-related manner
compared with that of the rabbits fed a normal diet. The increase was
associated with vascular heterogeneity of regions. There was a
significant correlation between plaque area and vascular ACE activity
in the aortic arch isolated from rabbits fed the higher (1.5 %)
cholesterol diet. Contractile responses of the femoral artery to
angiotensin I and II in the atherogenic diet-fed rabbits did not
differ from those fed the normal diet. It is conceivable that
increased ACE in the vascular walls is involved in hyperlipidemia
-induced atherogenesis, presumably through production of growth or
stimulating factor (s) contributing to plaque formation.
Received 6 July 1995; accepted in final form 8 March 1996.
APS Manuscript Number H621-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96