Researchers at NIH have extended the lifespan of mice by 20 percent by lowering the expression of a single gene, the mTOR gene:
The researchers engineered mice that produce about 25 percent of the normal amount of the mTOR protein, or about the minimum needed for survival. The engineered mTOR mice were a bit smaller than average, but they otherwise appeared normal.
The median lifespan for the mTOR mice was 28.0 months for males and 31.5 months for females, compared to 22.9 months and 26.5 months for normal males and females, respectively. The mTOR mice also had a longer maximal lifespan; seven of the eight longest-lived mice in this study were mTOR mice. This lifespan increase is one of the largest observed in mice so far.
While the genetically modified mTOR mice aged better overall, they showed only selective improvement in specific organs. They generally outperformed normal mice of equivalent age in maze and balance tests, indicating better retention of memory and coordination. Older mTOR mice also retained more muscle strength and posture. However, mTOR mice had a greater loss in bone volume as they aged, and they were more susceptible to infections at old age, suggesting a loss of immune function.