title: Contribution of monocyte-derived macrophages and smooth muscle cells to arterial foam cell formation.
abstract: Smooth muscle cells (SMCs) are the main cell type in intimal thickenings and some stages of human atherosclerosis. Like monocyte-derived macrophages, SMCs accumulate excess lipids and contribute to the total intimal foam cell population. In contrast, apolipoprotein (Apo)E-deficient and LDL receptor-deficient mice develop atherosclerotic lesions that are macrophage- as opposed to SMC-rich. The lesser contribution of SMCs to lesion development in these mouse models has distracted attention away from the importance of SMC cholesterol homeostasis in the artery wall. Intimal SMCs accumulate excess amounts of cholesteryl esters when compared with medial layer SMCs, possibly explained by reduced ATP-binding cassette transporter A1 expression and ApoA-I binding to intimal-type SMCs. The aim of this review is to compare the relative contribution of monocyte-derived macrophages and SMCs to human vs. mouse atherosclerosis, and describe what is known about lipid uptake and removal mechanisms contributing to arterial macrophage and SMC foam cell formation. An increased understanding of the contribution of these cell types to lesion development will help to delineate their relative importance in atherogenesis and as potential therapeutic targets.
authors.affiliation: Department of Medicine,  UBC James Hogg Research Centre, Providence Heart + Lung Institute at St Paul's Hospital, Room 166, Burrard Building, 1081 Burrard Street, Vancouver, BC,  Canada V6Z 1Y6.
authors.forename: Sima
authors.initials: S
authors.lastname: Allahverdian
authors.forename: Parveer S
authors.initials: PS
authors.lastname: Pannu
authors.forename: Gordon A
authors.initials: GA
authors.lastname: Francis
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism / Q000473:pathology; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D002784:Cholesterol / Q000378:metabolism; D005487:Foam Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008264:Macrophages / Q000166:cytology*; D051379:Mice; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology
chemical_list: D002784:Cholesterol