Diabetes-induced disruption of the SIRT1-LXR axis and reduced oxysterol production due to loss of cytochromes P450, 27A1, and 46A1 in the retina result in diminished cholesterol removal leading to inadequate vascular repair, macrophage/microglia activation, and widespread retinal pathology (88, 89, 90). The gene discussed is SIRT1; the disease is diabetes mellitus.