NOS3 and type 2 diabetes mellitus: We also observed less eNOS expression in subdermal biopsies from patients with T2DM (Mahmoud et al., 2016; Chen et al., 2018) and recently reported that chemokine receptor CCR10 activation by ligand CCL28 leads to a decrease in eNOS expression and NO production (Chen et al., 2020) resulting in defective angiogenesis in diabetic mice (Chen et al., 2022).