The scope of the Atherosclerosis and Lipoprotein Analysis Core facility is the quantitative assessment of atherosclerosis lesion areas at two locations in mouse models. For the aortic root assay, each individual investigator is only responsible for providing the excised saline-perfused heart in 10% phosphate buffered formalin. The Core personnel will then: 1) embed the heart in gelatin, 2) freeze the gelatin block in OCT, 3) prepare 5 slides containing four 12.5 micron thick sections each, that cover the first 500 microns of the aortic root, 4) stain the slides in oil red O, hematoxylin, and fast green, and 5) quantitate the lesion areas on one section per slide and calculate the mean lesion are per section. For the en face assay, the Core will provide a trained technologist to work under the project leader's approved protocol to: 1) anesthetize the mice, 2) perform saline perfusion, which euthanizes the mouse by exsanguination, 3) dissect the mouse to display the mouse aorta in situ, 4) remove the aorta and trim off adventitial tissue, 5) cut the aorta longitudinally and fix it flattened between two microscope slides, 6) stain the aorta with oil red O, 7) mount the aorta on a microscope slide, and 8) quantify the % surface lesion area in the entire aorta, as well as in the regions of the aortic arch, and thoracic and abdominal aortas.