RBP4 regulates macrophage foam cell formation and enhances chronic endothelial inflammation through the activation of macrophages, mediated through the c-Jun-N-terminal protein kinase (JNK) and Toll-like receptor 4 (TLR-4) pathways, along with the activation of NADPH oxidase and NF-Κb [6, 33]. Here, TLR4 is linked to inflammation.