The macrophage in atherosclerosis: modulation of cell function by sterols

Lipid-laden macrophage foam cells are an early and persistent component of atherosclerotic lesions, As such they are likely to play a key role in dise ase progression, both as scavengers of lipid and as inflammatory mediators. The sterol content of macrophage foam cells is largely native cholesterol together with a small but significant proportion of oxidized cholesterol (o xysterols), Few in vitro investigations of the influence of sterol accumula tion oil macrophage function have used cells that contain physiologically o r even pathologically representative amounts of cholesterol or, more partic ularly, oxysterols, However, recent studies, using macrophages with a stero l content much closer to that of authentic foam cells, show that the presen ce of oxysterols causes an impairment in macrophage cholesterol export, sug gesting a hey role for oxysterols in the maintenance of the foam cell pheno type, The implications of physiologically relevant levels of oxysterols on a wider range of macrophage function remain to be investigated.