title: Fibromuscular cap composition is important for the stability of established atherosclerotic plaques in mature WHHL rabbits treated with statins.
abstract: We examined the relationship between plaque vulnerability and fibromuscular cap composition using hydrophilic pravastatin and lipophilic fluvastatin. WHHL rabbits aged 10 months were given pravastatin (50 mg/kg) or fluvastatin (20 mg/kg) for 52 weeks. The atherosclerotic lesions were immunohistochemically or conventionally stained and the components were analyzed with a color image analyzer. Compared with the control group, the plasma cholesterol levels were decreased by about 25% in both statin groups. Pravastatin decreased the lipid components (macrophages+extracellular lipids) in whole aortic plaques by 34% and the fibrous caps of coronary plaques by 55%. Fluvastatin decreased the fibromuscular components (smooth muscle cells+collagen fibers) in whole aortic plaques and in the fibromuscular caps of the aortic and coronary plaques. In the pravastatin group, the vulnerability index, the ratio of (lipid components)/(fibromuscular components), was decreased in whole aortic plaques by 28% and in the fibromuscular caps of coronary lesions by 61%, while the indexes were increased in the fluvastatin group. The incidence of vulnerable plaques was decreased by 74% in the coronary plaques of the pravastatin group. Our results suggest that the stability of atheromatous plaques was improved due to a decrease of the lipid components and vulnerability index of the fibromuscular cap by pravastatin.
authors: Institute for Experimental Animals, Kobe University School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. ieakusm@med.kobe-u.ac.jp
authors: M
authors: M
authors: Shiomi
authors: T
authors: T
authors: Ito
authors: Y
authors: Y
authors: Hirouchi
authors: M
authors: M
authors: Enomoto
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001161:Arteriosclerosis / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology* / Q000627:therapeutic use; D000077340:Fluvastatin; D007211:Indoles / Q000494:pharmacology* / Q000627:therapeutic use; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D017035:Pravastatin / Q000494:pharmacology* / Q000627:therapeutic use; D011817:Rabbits
chemical_list: D000924:Anticholesteremic Agents; D005229:Fatty Acids, Monounsaturated; D007211:Indoles; D000077340:Fluvastatin; D017035:Pravastatin