HSPB1 and diabetes mellitus: However, proinflammatory cytokines that are generally upregulated in the diabetic retina (Joussen et al., 2004; Abu El-Asrar, 2012; Wang et al., 2018) reduce the levels of HspB1 in retinal capillary endothelial cells, which could lead to their apoptosis in diabetic retinopathy (Nahomi et al., 2014).