Effect of lanthanum chloride on established atherosclerosis in the cholesterol-fed rabbit. Mitral valve as a site for assessment of treatment effects.

ABSTRACT

The ability of lanthanum chloride (LaCl3) to retard the progression of established atherosclerosis was investigated in cholesterol-fed rabbits. Rabbits were initially maintained on a high-fat plus cholesterol-supplemented diet for 10 weeks to induce lesions and were then changed to a low-fat diet or a low-fat diet supplemented with LaCl3 for an additional 24 weeks to permit their serum cholesterol levels to normalize. LaCl3 did not affect the rate at which serum cholesterol levels returned to normal. The dose of LaCl3 was approximately 30 mg/kg body weight/day. In comparison with controls, LaCl3-treated rabbits exhibited histologically less severe coronary artery and mitral valve atherosclerosis. Lesion severity in the carotid arteries was unaffected by LaCl3 treatment. Although statistically significant, the salutary effects of LaCl3 were relatively small. The data support the hypothesis that calcium antagonists can retard the progression of established atherosclerotic lesions. The data also illustrate the value of the mitral valve as a site to assess treatment effects on monocyte/macrophages in vivo.