We generated
apoE(-/-) mice deficient in
GM-CSF (
apoE(-/-).
GM-CSF(-/-) mice), fed them a high-fat diet, and compared lesion development with
apoE(-/-) mice. We measured lesion size, macrophage, smooth muscle cell, and
collagen accumulation at the aortic sinus, and expression of genes that regulate
cholesterol transport and
inflammation. No differences in serum
cholesterol were found between the 2 groups. Lesion size in hyperlipidemic
apoE(-/-).
GM-CSF(-/-) increased by 30% (P<0.05), macrophage accumulation doubled, and
collagen content reduced by 15% (P<0.05); smooth muscle cell accumulation and vascularity were unaffected. Analysis of
PPAR-gamma, ABCA1, and CD36 in lesions showed reduced expression (50%, 65%, and 55%, respectively), whereas SR-A doubled. In peritoneal macrophages,
PPAR-gamma and ABCA1 expression was also reduced by 50% and 70%, respectively, as was
cholesterol efflux, by 50%. In lesions, pro-inflammatory MCP-1 and
tumor necrosis factor (
TNF)-alpha expression increased 2- and 3.5-fold, respectively,
vascular cell adhesion molecule (VCAM)-1 expression enhanced and
interleukin (IL)-1 receptor antagonist reduced by 50%.
CONCLUSIONS: