Figure 1.

Schematic diagram of the consequences of apoptotic cell death in atherosclerosis. In early plaques, smooth muscle cells (SMCs) and macrophages (MΦ) undergo apoptosis and are then rapidly and safely cleared by neighbouring phagocytes. The net effect is a reduction in lesion cellularity and plaque growth. In advanced lesions, phagocytic clearance of apoptotic cells is not efficient so that secondary necrosis may occur, leading to inflammation, necrotic core formation and further plaque destabilization. Importantly, in both early and advanced plaques, death of SMCs may lead to a reduction in collagen synthesis, which in turn, leads to thinning of the fibrous cap, particularly in the more advanced stages of atherosclerosis. Loss of collagen is enhanced by the release of matrix metalloproteinases (MMPs).