Beneficial effects of ACE-inhibition with zofenopril on plaque formation and low-density lipoprotein oxidation in watanabe heritable hyperlipidemic rabbits
C. Napoli et al., Beneficial effects of ACE-inhibition with zofenopril on plaque formation and low-density lipoprotein oxidation in watanabe heritable hyperlipidemic rabbits, GEN PHARM, 33(6), 1999, pp. 467-477
The effects of angiotensin-converting enzyme (ACE)-inhibition with zofenopr
il on the development of atherosclerosis and low-density lipoprotein (LDL)
oxidation were determined in Watanabe Heritable Hyperlipidemic (WHHL) rabbi
ts. Rabbits received either placebo (n = 6) or 0.5 mg/kg/day of zofenopril
(n = 6). After 6 weeks of treatment, the computer-assisted analysis reveale
d that zofenopril reduced the aortic and common carotid corrected cumulativ
e lesion area by 34% and 39%, respectively (p < 0.05 vs placebo-treated gro
up). The intimal/medial ratio of the largest fatty streaks was 0.426 +/- 0.
158 in the zofenopril-treated group and 0.875 +/- 0.238 in the placebo-trea
ted group (p < 0.05). Furthermore, we found in the zofenopril-treated group
smaller lesions with an intimal/medial ratio of zofenopril also reduced pl
asmatic LDL oxidation, as shown by significant reduction of malondialdehyde
content (p < 0.01) and relative agarose gel mobility (p < 0.05), as well a
s by the prolongation of the lag-time (p < 0.05), Compared to zofenopril-tr
eated rabbits, arterial sections of the placebo-group had significant incre
ase in the intimal presence of macrophages-derived foam cells (p < 0.05), o
x-LDL (p < 0.01), and native LDL (p < 0.01) detected by immunocytochemistry
with RAM-11, MDA2 and NP1533975 monoclonal antibodies, respectively. To in
vestigate the amount of platelet accumulation in the atherosclerotic plaque
we also measured platelet-associated radioactivity. Autologous platelets w
ere labeled with (111)Indium-oxine and injected intravenously. After 2 hour
s, WHHL were sacrificed and arterial sections were counted for platelet-ass
ociated radioactivity. In the placebo-treated group, platelet radioactivity
was 0.52 +/- 0.12 equivalent of radioactivity per mg of tissue in the comm
on carotid and 0.25 +/- 0.18 in the abdominal aorta; in contrast, rabbits t
reated by zofenopril had 0.20 +/- 0.12 in the com mon carotid and 0.06 +/-
0.01 in the abdominal aorta. These data indicate that ACE-inhibition with z
ofenopril has antiatherosclerotic and antioxidant effects in WKHL-rabbits.
Our results also shows that these effects could be linked to a reduced wall
-associated platelet deposition at the site of atherosclerotic lesions. (C)
2000 Elsevier Science Inc. All rights reserved.