Intimal pericytes as the second line of immune defence in atherosclerosis

Inflammation plays an essential role in the development of atherosclerosis. The initiation and growth of atherosclerotic plaques is accompanied by recruitment of inflammatory and precursor cells from the bloodstream and their differentiation towards pro-inflammatory phenotypes. This process is orchestrated by the production of a number of pro-inflammatory cytokines and chemokines. Human arterial intima consists of structurally distinct leaflets, with a proteoglycan-rich layer lying immediately below the endothelial lining. Recent studies reveal the important role of stellate pericyte-like cells (intimal pericytes) populating the proteoglycan-rich layer in the development of atherosclerosis. During the pathologic process, intimal pericytes may participate in the recruitment of inflammatory cells by producing signalling molecules and play a role in the antigen presentation. Intimal pericytes are also involved in lipid accumulation and the formation of foam cells. This review focuses on the role of pericyte-like cells in the development of atherosclerotic lesions.