Mitochondrially-targeted antioxidants - such as catalase - have been shown to extend life span in mice. Here is a method of using catalase that employs a viral vector: "Earlier studies have found that mice would live longer when their genome was altered to carry a gene known as mitochondria-targeted catalase gene, or MCAT. However, such approaches would not be applicable to human. Duan and Dejia Li [took] a different approach and placed the MCAT gene inside a benign virus and injected the virus into the mice. Once injected, Duan and Li tested the mice and found that they could run farther, faster and longer than mice of the same age and sex. Duan attributes this performance enhancement to the MCAT and believes the gene is responsible for removing toxic substances, known as free radicals, from the mitochondria, the powerhouse of the cell. By using this specific gene therapy vector, the virus, to introduce the longevity gene, Duan and Li opened the possibility of human treatment. ... Our results suggest similar therapy may one day improve the life quality of the elderly. This could have important implications for many diseases, such as muscular dystrophy, heart disease, diabetes and neurodegenerative diseases. These patients typically have too many toxic free radicals in their cells."