> The Bristol team, led by Professor Paolo Madeddu, has found that a single administration of the mutant anti-aging gene halted the decay of heart function in middle-age mice. Even more remarkably, when given to elderly mice, whose hearts exhibit the same alterations observed in elderly patients, the gene rewound the heart’s biological clock age by the human equivalent of more than ten years.

That's where "rewind" comes from. It restored cardiac function in elderly mice when administered late in life.