Immunofluorescence staining of PECAM-1 showed that aorta sinus sections from both xyloketal B and simvastatin treated apoE−/− mice exhibited relative normal appearance of endothelium, in comparison to apoE−/− mice, indicating that xyloketal B could maintain vascular endothelial integrity against atherosclerosis. This evidence concerns the gene PECAM1 and atherosclerosis.