CHOLESTEROL RESPONSE AND FOAM CELL-FORMATION IN HAMSTERS FED 2 LEVELSOF SATURATED FAT AND VARIOUS LEVELS OF CHOLESTEROL

Two levels of saturated fat (31 and 39% of the calories) and several l evels of cholesterol were fed to weanling male hamsters in order to ev aluate their atherogenicity and foam cell formation in the aortic arch , Diets contained 5% cellulose, 20% casein, and either 15% butterfat p lus 0, 0.05, 0.5 or 3% cholesterol (C) or 20% butterfat plus 0 or 0.5% C, Total plasma cholesterol (TC) was significantly (P less than or eq ual to 0.05) elevated when dietary fat was increased from 15 to 20% wi th no added cholesterol (232 vs 262 mg/dl). Addition of 0.05, 0.5 or 3 % C to 15% fat diet, or 0.5% C to 20% fat diet resulted in significant TC elevations compared with their respective no added C controls (301 , 383 and 533 vs 232 and 490 vs 262 mg/dl, respectively). With 0.5% ad ded C, plasma cholesterol values with 20% fat diet were significantly greater than those with 15% fat (490 vs 383 mg/dl). Increased TC was m ainly due to significant elevations in VLDL and LDL cholesterol levels , which resulted in a significant decrease in HDL/LDL cholesterol rati os. Elevations in TC and reductions in HDL/LDL cholesterol ratios were similar in hamsters fed 15% fat with 3% cholesterol or 20% fat with 0 .5% cholesterol, Liver cholesterol increased significantly with increa sed dietary cholesterol up to 0.5%, Foam cell formation was significan tly greater in animals fed 0.5 or 3% added cholesterol with 15 or 20% fat diet compared with low (0 or 0.05% added) C diets. Significant pla sma and liver cholesterol elevations, lower HDL/LDL cholesterol ratios and increased foam cell formation indicate that a diet containing a h igher level of saturated fat and lower cholesterol is as atherogenic a s a diet with lower fat and high cholesterol, Significant foam cell fo rmation in 6 weeks by feeding 0.5% cholesterol and 20% butterfat diet to hamsters suggests that this model is suitable for atherosclerosis p rogression and regression studies within a reasonable time frame.