A very interesting paper has just been published about aging in worms. The paper basically uncovers evidence that goes against the current thinking about how and why animals age and might in the future shed light on how and why humans age. Worms? Yes, because they are a good genetic model that is easy to grow and experiment on.

Some background: there are two theories that explain how cells and animals age:

• Cells get damaged and the damage accumulates over time, which leads to cells malfunctioning and dying.

• The control mechanisms inside the cell break over time leading to the cell's processes to stop functioning properly, something descriptively called antagonistic pleiotropy.

Cell damage can come from sources such as cellular stress, free radicals, and disease, and there is evidence to support this theory. The life span of worms can be extended by feeding them harmless bacteria and growing them in conditions that reduce cell damage. Some experimental strains of worms have longer lifespans because they have mutations that allow them to survive stress better. So there is evidence for this kind of thinking but it's not the whole story.

Today's paper uncovers 3 genes that are master control switches for many cellular processes - they control over 1200 genes in total! These genes, known as elt-3, elt-5, and elt-6, interact: elt-5 and elt-6 inhibit elt-3 late in life and lower levels of elt-3 mean that some processes are switched off. When the researchers knocked out elt-5 and elt-6 (i.e. removed their inhibitory effects), high levels of elt-3 were seen in older worms just like in younger worms, and not just that, the worms lived longer - about 25 days compared to 20 days.

So what does this mean? The evidence in this paper looks good and of course it needs to be repeated and validated. Furthermore, it may or may not apply to humans because humans live for decades as opposed to the days a worm lives which could mean that different aging mechanisms may be important in humans. Still, this research opens the door for further experimentation and gives us a handle on how to approach this age-old problem.