SP1 and Hyperglycemia: According to previous studies, multiple putative binding sites in the region of the TSP-1 promoter can be activated by hyperglycemia to increase its expression, and some of these TSP-1-stimulating factors include upstream stimulatory factors (USF), activator protein 1 (AP1), E2F1, nuclear factor-kappa B (NF-κB), early growth response 1 (Egr1), and stimulating protein (Sp1) [17–23] (Figure 1(b)).