SOD1 and skin atrophy: Our previous studies have demonstrated that Sod1-deficient (Sod1−/−) mice exhibit increased intracellular O2− concentrations and various aging-related organ phenotypes, such as age-related macular degeneration [5], fatty deposits in the liver [6], [7], skin atrophy [8]–[11], bone loss and fragility [12], [13], progression of Alzheimer's disease [14], infertility [15], dry eye [16], [17], and rotator cuff degeneration [18].