RBP4 and peripheral arterial disease: Previous studies have shown that in obese patients, adipose-related factors such as Retinol-Binding Protein-4 are significantly increased, which mediate the proliferation of vascular smooth muscle cells, and increase pro-inflammatory cytokines such as Tumor necrosis factor-alpha (TNF-alpha) and interleukins 1β, 2, 8, 10 (IL-1β, IL-2, IL-8, IL-10) and adhesion molecules such as vascular cell adhesion molecule 1, thereby aggravating the occurrence and development of PAD (5, 27).