PARP1 and diabetes mellitus: This is consistent with our previous SIRT1-related findings (Wachal et al., 2020): SIRT1 inactivates NFkB and PARP1 physiologically; however, in diabetes, SIRT1 is downregulated leading to over-transactivation of detrimental genes in the diabetic eye, such as MMP9, an enzyme known to be involved in the development of mitochondrial damage in diabetic retinopathy (Kowluru et al., 2014a).