SOD1 and osteoporosis: Although both global knockout of cytoplasmic Sod1 as well as osteocyte-specific knockout of mitochondrial Sod2 seem to result in an osteoporosis-like phenotype in mice (Nojiri et al., 2011; Kobayashi et al., 2015), several studies imply differences in the expression and the role of these antioxidative enzymes in bone.