Lipid characterization in an animal model of atherosclerosis using NMR spectroscopy and imaging.

High resolution 1H and 13C NMR spectroscopic measurements including 1H/13C 2D correlation and magnetic resonance imaging (MRI) studies, have been carried out on intact rabbit aortic tissues ex vivo using animals fed both normal and high cholesterol diets. The results show that 1H and 13C NMR spectroscopy can distinguish mobile lipids and can differentiate between normal triglyceride content and cholesterol-enriched lipids, in intact tissue, There were considerable differences in the level of deposition of cholesteryl esters in animals all fed on the same diet. Confirmation is presented of temperature-dependent differences in mobility and organization between the triglycerides found in control tissue and the cholesteryl esters found in aortas from high lipid diet animals. Water-suppressed MRI showed evidence of lipid accumulation in the aortas of high cholesterol diet rabbits. It is concluded that the hypercholesterolaemic rabbit model of atherosclerosis, coupled with such NMR methods, may offer a noninvasive method of monitoring disease development, allowing the evaluation of the effect of therapeutic agents on the progress of atherosclerosis.