DIET-INDUCED ATHEROSCLEROSIS IN THE DOMESTIC CAT

The domestic cat has not been used in studies of atherosclerosis, with the exception of a single study published in 1970. We have further ev aluated the susceptibility of the domestic cat to diet-induced atheros clerosis, the ultimate intent being to discern the atherogenic risk du e to lipoprotein lipase deficiency in an affected feline kindred with a phenotype very similar to that of the human form of this condition. We subjected a group of normal domestic oats to a moderately high-fat, cholesterol-enriched diet (30% fat and 3% cholesterol) for a period o f 2 to 8 months. Plasma lipid levels were monitored monthly. At the ti me of killing, all organs and the entire vascular tree were removed, s ectioned, processed, and stained with hematoxylin and eosin. The entir e vascular tree was also stained with Movat's pentachrome and oil red O (ORO) and assessed semiquantitatively (0 to 5+/5+) and quantitativel y (mean intimal area and ORO positivity, mm(2)). Both blood lipid meas urements (total cholesterol, high-density lipoprotein-cholesterol, tri glycerides, and low-density lipoprotein-cholesterol) and vessel wall l esion assessment (intimal area, mm(2)) were statistically elevated (p < 0.05) in the cholesterol-fed cats as compared to those on a normal d iet. The highest correlations obtained between blood lipid components and vessel wall measures were the percent increase in triglyceride fro m base line versus the ORO measurement or foam cell grade (r = 0.86), and percent increase in triglycerides versus the intimal area in the l ower abdominal aorta (r = 0.91). Similar relationships were found when the intimal area in the brachiocephalic/subclavian vessels was correl ated with the absolute triglyceride values (r = 0.85) or with the perc ent increase in triglycerides (r = 0.83). Thus, we produced atheroscle rotic lesions in the cat within 2 to 4 months on a cholesterol-enriche d diet; blood lipid levels were highly correlated with lesional measur ements in the vessel wall. This study will provide the basis for evalu ation of the susceptibility of New Zealand lipoprotein lipase-deficien t cats to diet-induced atherosclerosis.