Zhong and Kowluru observed that transient hyperglycemia increased H4K20me3, acetylated H3K9, and NF-κB p65 levels at the promoter and enhancer of retinal sod2, which encodes Mn-SOD, reducing mitochondrial overproduction of superoxide and contributing to downregulation of Sod2 expression in animal models and retinal endothelial cells [58]. This evidence concerns the gene NFKB1 and Hyperglycemia.