Ouroburos writes about a new article in Nature Biotechnology that sheds doubt about the resveratrol-sirtiun story as told by Dr. Sinclair. If anyone has access to the original Nature article please pass on the highlights. Excerpt:
… But there is another sirtuin narrative that has received much less attention. To begin with, there is no published evidence that resveratrol or sirtuin activators can extend lifespan in normal mammals. Calorie restriction does extend lifespan in many organisms (though not all), but its effects in mammals may have little to do with the sirtuins: other pathways may be more important. And resveratrol may not be a general sirtuin activator in the first place—the compound’s beneficial effects may arise from completely different mechanisms. Finally, credible research in yeast suggests that sirtuins may actually function to limit chronological lifespan, not increase it.
Chris Patil (ouroboros) had this comment:
The piece summarizes, thoroughly and fairly, the arguments for and against the competing narratives regarding sirtuins’ importance; in the process, it gives a nice historical overview of the evolution of the sirtuin field since its foundations in yeast.
By pointing out the importance of narrative, Garber reminds us that sometimes we tend to preferentially remember facts that improve the consistency of a story, and conversely, to preferentially forget completely valid observations that add rough edges and sharp corners to a favored view. This field is rife with examples. Here, we are reminded of some of the prima facie weaknesses of some of founding studies, including ones that led to such fundamental beliefs as the idea that resveratrol activates sirtuins. We’re also pointed toward the work of dissenting scholars who find that sirtuin mutations and resveratrol have minimal, if any, effect on lifespan — raising the possibility that any such effects observed in other studies are sensitively dependent on the choice of culture conditions and the genetic backgrounds of the animals used.
On the balance, the piece doesn’t argue that sirtuins aren’t involved in aging or that they’re not worth further study — but after reading it, I found myself realizing that some of the parts of the big machine don’t fit together as smoothly as I thought they had. Especially when a theory is widely accepted — and widely used as an inspiration for future studies — it’s crucial to be regularly reminded of what we know for sure, why we think we know it, and (most importantly) of the magnitude of what we don’t yet know.
http://ouroboros.wor...ome-under-fire/
