De Grey also wants anti-aging therapists of the future to correct a cellular design flaw that abets damage from highly reactive molecules called free radicals. (Free radicals are the baddies that supposedly can be neutralized with "antioxidants" such as vitamins E and C.) That vulnerability stems from the way our DNA is positioned in our cells. Most of our DNA nestles safely within the cell nucleus. But a small fraction of it (13 genes, to be exact) is found outside the nucleus in cellular structures called mitochondria, which serve as our bodies' energy generators. Trouble is, mitochondria churn out free radicals that can clobber their small parcels of DNA. Over time, such damage may dim our cells' power supplies. To prevent it, de Grey proposes putting functioning copies of the damage-prone mitochondrial DNA into the protective confines of the cell nucleus. Studies dating from the mid-1980s have already shown that this is perfectly feasible, he adds. The method of choice, once again, would be gene therapy.
This is theoretically feasible, but there are problems: there are can be as many as 1000 mitochondria per cell requiring an enormous amount of transcription to be occurring in the nucleus meaning that this region of DNA will be exposed for unusually long periods, thereby diminishing protection afforded by histones; the issue of mutant mitochondria that are dysfunctional yet have a selective advantage over normal mitochondria also cannot be addressed by this method.
Rather more effective and simple a solution is to introduce additional DNA repair and protection enzymes into mitochondria. There are also organisms out there with far more effective DNA repair and protection enzymes than ours, whose genes we could also therapeutically introduce.
Using this method the probability of DNA damage in mitochondria would be dramatically reduced with a concomitant reduction in cell death due to apoptosis.