Effect of lercanidipine and its (R)‐enantiomer on atherosclerotic lesions induced in hypercholesterolemic rabbits

Abstract
The in vivo antiatherogenic activity of the calcium antagonist lercanidipine and its (R)‐enantiomer was investigated in two different types of atherosclerotic lesions (hyperplastic and fatty‐streak lesions) in rabbits. Lercanidipine (0.3, 1, and 3 mg kg−1 week−1) as well as its (R)‐enantiomer at 3 mg kg−1 week−1 were given by subcutaneous injection for 10 weeks to White New Zealand rabbits, with cholesterol feeding beginning at week 2. The hyperplastic lesion was obtained by positioning a hollow silastic collar around one carotid artery, while aortic fatty streak lesions were induced by cholesterol feeding. In untreated animals (n=5), 14 days after collar positioning an intimal hyperplasia was clearly detectable: the arteries without collar showed a intima/media (I/M) ratio of 0.03±0.02, whereas in carotids with a collar the ratio was 2±0.42. In lercanidipine‐treated animals a significant and dose‐dependent effect on intimal hyperplasia was observed. I/M ratios were 0.73±0.4, 0.42±0.1, 0.32±0.1 for 0.3, 1, and 3 mg kg−1 week−1, respectively (P−1 week−1) was as effective as the racemate (0.41±0.11). Proliferation of smooth muscle cells, assessed by incorporation of BrdU into DNA, was reduced by about 50%, 70%, 85%, and 80% by lercanidipine (0.3, 1, and 3 mg kg−1 week−1) and its (R)‐enantiomer, respectively. The area of fatty‐streaks in the aorta (n=11–15) was significantly reduced by lercanidipine (3 mg kg−1 week−1, 16% vs 27%, PBritish Journal of Pharmacology (1998) 125, 1471–1476; doi:10.1038/sj.bjp.0702221