Stem cells could make good on the promise of partial reprogramming for rejuvenation therapies KATERYNA KON/SCIENCE PHOTO LIBRARY/Alamy I’ve covered the ageing field for many years and seen a lot of promising rejuvenation therapies get hyped up then fall flat on their faces. Ground zero for this repeated cycle was resveratrol, a natural compound once touted by biotech company Sirtris Pharmaceuticals as a miracle anti-ageing drug. In 2008, pharmaceutical giant GlaxoSmithKline bought the company for $720 million, only to pull the plug five years later after the compound turned out to be a dud . Similar disappointments have bedevilled caloric restriction , drugs targeting the ageing master switch MTOR and senolytics designed to clear out zombie cells that are a key driver of ageing. So when I heard about the first clinical trial of a new class of rejuvenation drugs, I tried not to get too excited. But the more I looked, the more I started to think, maybe this time it’s different.…