We accuse cholesterol of causing atherosclerotic plaques because we may find lipoproteins alongside such plaques. As we will see in Chapter Twelve, analysis of plaques shows them to be comprised primarily of polyunsaturated fats. Given that fat and cholesterol particles are travelling around the blood stream in lipoproteins, if anything causes a lesion along the endothelial wall (the lining of an artery), it is virtually guaranteed that some lipoproteins will get caught by this lesion.