Cuteness is in the eye of the beholder, I realize. But I think this roundworm is pretty adorable. And although they're not killifish, laboratory roundworms also provide a great way to study longevity.
I've been interested in studies of longevity (and a killifish fan!) since I wrote an article for Stanford Medicine magazine about the work of geneticist and longevity expert Anne Brunet, PhD. Now, Brunet and graduate student Shuo Han, have uncovered an interesting (and palatable!) connection between DNA regulation, lifespan and diet in roundworms. They published their results today in Nature.
In short, the researchers found that a diet high in monounsaturated fatty acids like those found in olive oil, avocados and nuts can increase the worms' lifespan. The finding is particularly interesting because these foods are all components of the so-called Mediterranean diet that is sometimes associated with reduced disease risk and longer life in humans. It is also surprising because other studies have suggested that caloric restriction, which is not conducive to fat accumulation, is associated with longevity.
As I described in our release:
The researchers began their study as a way to explore epigenetics, a process by which organisms modulate their gene expression in response to environmental cues without changing the underlying sequence of their DNA. In this case, the researchers were looking at how epigenetic protein complexes, which add or remove chemical tags on the cell’s DNA packaging machinery, might interact with metabolic changes in a roundworm to affect its life span.
'It’s well-known that epigenetic protein complexes and metabolic pathways both affect life span in many animals,' said Brunet... 'But until now we didn’t know why, or whether these two processes were linked in some way.'
The researchers focused their attention on a clump of proteins called COMPASS. They knew from previous research that blocking the function of COMPASS somehow extended the worms' lifespan by as much as 30 percent. Han decided to investigate whether this lifespan effect could be related to metabolic changes.
Han learned that the worms lacking COMPASS function accumulated a specific type of fat called monounsaturated fatty acids in their guts. As Brunet explained in our release:
We wanted to know whether this accumulation of monounsaturated fats was important to life span, so we fed both monounsaturated and polyunsaturated fats directly to the worms. We found that the monounsaturated fats accumulated in the worms’ guts and increased their life span even when COMPASS was not mutated. In contrast, polyunsaturated fats did not have the same effect.
It's too soon to conclude that we should all change our diets and assume that more fat accumulation is a sure-fire way to live longer. But Brunet is probably covered. As she said laughingly, "I was born in France and completed my doctoral studies at the University of Nice on the Mediterranean coast. So, in a way, I have already been on this diet for many years."
Previously: A tiny fish helps solve how genes influence longevity, Living Loooooooonger: A conversation on longevity and Male roundworms shorten females' lifespan with soluble compounds, say Stanford researchers
Photo by Bob Goldstein, UNC Chapel Hill