The bio page for Aubrey de Grey at the Manhattan Beach Project website includes a ten minute video presentation on the contribution of mitochondrial damage to aging, and how to reverse it. You should take a look: "Aubrey's indepth presentation to a roomful of scientists gathered at the Manhattan Beach Project, [which] includes an update on his mitochondrial free-radical theory of aging and a description of how regenerative medicine may be able to thwart the aging process altogether." You might also want to read up on the MitoSENS research program at the SENS Foundation website: "Mitochondria are very complex; they contain about a thousand different kinds of protein, each encoded by a different gene. But nearly all of those genes are not in the mitochondrial DNA at all - they are in the nucleus! ... Only 13 of the mitochondrion's component proteins are still encoded by its own DNA, and it's therefore only these 13 genes that remain vulnerable to the constant assault from free radicals produced during respiration (the life-giving reaction of oxygen and food by the mitochondria). This gives us a wonderful opportunity: rather than fixing mitochondrial mutations, we can make them harmless to us. By putting 'backup copies' of these few remaining genes into the nucleus, we can prevent the harm caused by any mutations that may occur of the original versions."