Dr David Gems - a geneticist at University College London who has increased the lifespan of nematode worms by up to three times. He is investigating the genes which are responsible for this, many of which have human 'homologues'.

What do you hope to achieve through your work in understanding the ageing process?
What we know about ageing is that it's caused by genes - different species of animals have different life spans and the reason for that is that their genes are different. So I might live to be 80 and the worms that I work on die after about only 2/3 weeks. What we're trying to do is identify in worms the genes that control their life span, and then perhaps we can find the human equivalent and understand something about human nature.

How do you go about doing this? What have you found so far?
The way that we try to identify genes that control ageing is to look for animals which live longer because they've got something wrong with one of their genes. We've found strains that live much, much longer than normal because a particular gene has been changed. So, for example, if you change a particular gene called Daf 2 you can you can increase their life span by up to about 200% - for us that would be like living to be about 250 years old. What's really interesting is that this gene that controls ageing in worms has an equivalent in human beings, but what we don't know is whether the human equivalent of this gene is controlling human ageing.

What have you found out about the effects of calorie restriction on the ageing process?
Calorie restriction has been known about for a long time. If you take a laboratory rat and you reduce its calorie intake a certain amount, you can increase its life span by up to about 50%. The reason why life span is extended by calorie restriction may be something to do with evolution, it may be that in the wild when there's no food around animals have this way of adapting, reducing their fertility and slowing their rate of ageing. One thing we can say about calorie restriction is that it seems to work in all animals that have been looked at. There are trials at moment taking place in Rhesus monkeys and although it'll be a long time before we know the answer, they appear to be responding in the usual way, their ageing seems to be slower. So if calorie restriction seems to be working monkeys, the chances are that it would in principle work in us.

So we could eat less to live longer?
Unfortunately, if you want calorie restriction to work you have to reduce your calorie intake by about 40%, which is just near starvation levels. People have tried it and it's a very miserable life, you're hungry all the time and it's really not worth the pain for the gain. But there is the possibility that this group of genes that we've identified that controls ageing in worms - the Daf 2 genes - are actually the genes of calorie restriction, so maybe by understanding these genes we can understand how calorie restriction works and reduce the rate of ageing without having to reduce calories themselves.

How close are we to understanding and being able to affect the ageing process?
As far as really understanding ageing goes, I'm afraid that we're really at the beginning of a long road, but at least we are at last on the road. In the short term I think there's one thing that we may be able to understand, which is the way that animals can change their rate of ageing in response to diet, so that potentially could lead to therapies that might slow down human ageing to a degree. But I don't think that you'd be talking about anything more than adding a few decades to life. Those are things that in principle might be possible through hormone treatments and through drug treatments, but as far as anything more profound goes, as far as, for example, slowing ageing until it stops, curing ageing or anything of this sort, frankly I doubt whether that will ever be possible, at least by means of drugs or hormone therapies. I think to achieve that might be possible if you resorted to genetic engineering and actually altering the human genome - you'd have to really radically change human biology to be able to slow ageing down so that people would live centuries.

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Content last updated: 17/07/2006

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