Severe hypercholesterolemia and atherosclerosis in apolipoprotein E-deficient mice created by homologous recombination in ES cells.

apoE-deficient mice have been created by homologous recombination in ES cells. On a low fat, low cholesterol chow diet these animals have plasma cholesterol levels of 494 mg/dl compared with 60 mg/dl in control animals, and when challenged with a high fat Western-type diet, these animals have plasma cholesterol levels of 1821 mg/dl compared with 132 mg/dl in controls. This marked hypercholesterolemia is primarily due to elevated levels of very low and intermediate density lipoproteins. At 10 weeks of age, apoE-deficient mice have already developed atherosclerotic lesions in the aorta and coronary and pulmonary arteries. apoE-deficient mice are a promising small animal model to help understand the role of apoE in vivo and the genetic and environmental determinants of atherosclerosis.