The issue of the longevity gene has now created a trans-Atlantic feud between two camps of researchers. While the British scientists claim the gene is a bust, the U..S scientists still have faith in it.
Two papers published in the latest issue of the journal Nature reveal contradictory views on a gene called Sir2.
Sir2 previously was identified as a life-extending gene that produces sirtuins, found in everything from yeast to people. The more sirtuin that yeast, worms and mice produce, the longer the creatures lived, researchers found over the past decade. Further studies found that an animal's life span could be increased through calorie restriction --- a process mediated through sirtuin. Researchers also found that an ingredient in red wine, resveratrol, could activate sirtuin proteins, which look promising for anti-ageing products.
One paper in Nature argued that the original 2001 studies on life extension could not be replicated with different strains of worms or fruit flies, commonly used as model organisms, while another paper suggested Sir2 can indeed enhance longevity in animals but to a lesser extent than previously thought.
These results are very surprising, said David Gems, biologist at the Institute of Healthy Ageing at the University College London and lead researcher of the British study. We have re-examined the key experiments linking sirtuin with longevity in animals and none seem to stand up to close scrutiny. Sirtuins, far from being a key to longevity, appear to have nothing to do with extending life. But I think this is good news in a way: after all, revising old ideas can be as important as presenting new ones to assure scientific progress. This work should help to redirect scientific efforts toward those processes that really do control ageing.
Contesting the views of the British scientists, some said that the new study was faulty given that in the past 10 years, more than 3,000 papers published on the protein found a life-expansive connection.
They're wrong, in a word, said Leonard Guarente, biology professor at MIT whose lab first linked sirtuins with longevity in animals.
As far as sirtuins as targets for drug development, they're great and I don't think this new paper does anything to dampen that, said Guarente, who published a counter-study in Nature defending the original research.
In a seminal 2001 paper, Guarente's lab showed that ramping up production of sirtuins in worms increased their life span. The problem was that the worm strains had a mutation that affected life expansion.
Mea culpa, we did have a problem with one of our strains in our 2001 paper, Guarente told International Business Times. We addressed that in our new paper.
The issue isn't just technical - millions of dollars are potentially at stake. For example, GlaxoSmithKline, the pharmaceutical giant, bought the sirtuin-based biotech start up Sirtris Pharmaceuticals for $720 million in 2008.
The anti-ageing market is expected to grow to $292 billion by 2015, according to data from Global Industry Analysts, a marketing research firm in San Jose, Calif.