ABSTRACT
The normal blood vessel is comprised of three distinct layers or tunicae divided by internal and external elastic laminae. While mainly composed of both collagen and elastin connective tissue, each layer has particular cell types responsible for specific function. The innermost layer, the tunica intima, is separated from the vessel lumen by a thin layer of endothelial cells (EC), containing fibroblasts and myointimal cells in its sub-endothelial support structure. Atherogenesis can begin early in life with EC activation. The pathological process is initiated by lipid deposition seen early in the subendothelial space with resultant inflammatory cell infiltration. Two distinct types of plaques, white and yellow, have been defined which culminate in two physiological fates. Angiographic studies found that the white plaques correlate with cases of stable angina. These plaques typically have a dense fibrous cap and lower inflammatory cell infiltration, and thus, represent a more stable plaque.
