MMP9 and diabetes mellitus: Gewin et al. in 2020 discussed the biosynthesis pathway of several proteins including angiotensin II, reactive oxygen species (ROS), thrombospondin-1 (TSP-1), matrix metalloproteinases (MMPs) (MMP-2 and MMP-9), and hexosamine are involved in diabetes-induced TGF-β activity (Gewin et al., 2020 ▶).