BRASTO mice have raised levels of SIRT1 in the brain. Researchers are finding that altering levels of this sirtuin in brain tissues seems to have more of an impact than other manipulations, which to date haven't shown reliable extension of healthy life. At this point any result like the one below will have to be replicated before it can be taken seriously, however, given the contradictory data for sirtuins and life extension from the past decade.
Among scientists, the role of proteins called sirtuins in enhancing longevity has been hotly debated, driven by contradictory results from many different scientists. [Researchers have now] identified the mechanism by which a specific sirtuin protein called Sirt1 operates in the brain to bring about a significant delay in aging and an increase in longevity. Both have been associated with a low-calorie diet.
Sirt1 prompts neural activity in specific areas of the hypothalamus of the brain, which triggers dramatic physical changes in skeletal muscle and increases in vigor and longevity. "In our studies of mice that express Sirt1 in the brain, we found that the skeletal muscular structures of old mice resemble young muscle tissue. Twenty-month-old mice (the equivalent of 70-year-old humans) look as active as five-month-olds."
[The] team studied mice that had been genetically modified to overproduce Sirt1 protein. Some of the mice had been engineered to overproduce Sirt1 in body tissues, while others were engineered to produce more of the Sirt1 protein only in the brain. "We found that only the mice that overexpressed Sirt1 in the brain (called BRASTO) had significant lifespan extension and delay in aging, just like normal mice reared under dietary restriction regimens." The median life span of BRASTO mice in the study was extended by 16 percent for females and 9 percent for males. Delay in cancer-dependent death also was observed in the BRASTO mice relative to control mice.
It is unclear from the publicity materials whether this might be a result of inadvertent calorie restriction due to mice choosing to eat less under ad libitum conditions - it isn't enough just to let them eat what they want, you also have to measure the amount that they actually eat.