In atherosclerosis, increased LDL in monocyte/macrophage is due to -
Oxidized LDL is a particularly important relation to atherosclerosis.
Macrophages and endothelial cells generate oxygen free radicals that induce a chemical change in LDL to yield oxidized (modified) LDL. Oxidized LDL has following effects -


Ingested by macrophages through the scavenger receptor, distinct from LDL receptors, thus forming foam cells.
Increases monocyte accumulation in lesions.
Stimulates release of growth factors and cytokines.
Is cytotoxic to smooth muscle cells and endothelial cells.

Remember - Foam cells are lipid-laden cells that derive predominantly from macrophages, but smooth muscle cells can also imbibe lipid to become foam cells
LDL receptors on macrophage
LDL receptors on endothelium
Lipids in LDL get oxidized
All of the above