The Guardian reports on another breed of gene-engineered mice with increased longevity: "Experiments in male mice showed that those without a gene called IRS-1 lived 20% longer and had much healthier lives. Female mice without the gene had even better longevity, living 30% longer on average. In addition to longer lives, the mice without IRS-1 were much healthier than normal mice as they aged - they had brighter eyes, better immune function and healthier skin and bones. ... IRS-1 is involved in regulating the function of insulin, a hormone that controls the amount of sugar in the blood. [The results] add to a growing body of scientific work which points to a link between the genes that regulate insulin and how an animal ages. Similar genes in fruit flies and worms have already been linked to extended lifespan." Insulin regulation is becoming one of the more studied areas of metabolic manipulation - but building true repair technologies still beats out any tweak that lengthens life by reducing the wear on the system.

Link: http://www.guardian.co.uk/science/2007/oct/22/genetics