Aubrey de Grey wants to wish you a happy 200th birthday...

One of the other areas of research which SENS is focused on is extra-cellular cross links. Can you explain how this occurs?

Well, that’s actually quite a tricky one. Let’s use the lens of the eye as an example.

The lens of the eye can get stiffer. This means that the muscles which squeeze the lens to allow us to focus on objects at various distances – can’t squeeze so much. So, the question is, what’s happening there at the atomic / molecular level?

I’m massively over-simplifying– as it turns out that the chemistry of this is a huge subject – and that there are many alternative pathways and so on. But in the classical pathway which I’m describing here, the answer is, that like all extra-cellular proteins, the lens of the eye is bathed in fluid - which comes from the circulation in one way or another – and that has sugars in it.

Sugars are the main culprit here. Sugars are relatively unreactive molecules – but only relatively – so they react with proteins. And the first step of the reaction, which is basically that sugar ‘gloms’ on to particular amino acids – there are two out of the twenty amino acids which are very susceptible to this. And that’s okay so far, that’s just an adduct – a ‘thing’ hanging off the end of the protein – it doesn’t do any harm – yet. And generally, what happens next is that the adduct falls of again.

However, occasionally, the adduct undergoes a molecular re-arrangment and it becomes a different – much more stable – adduct, called an Amadori product. And once this happens, the adduct is more likely to stay there. Again, there it is, just hanging off the amino acid and not really a problem.

The third process that happens is a reaction that forms a thing called an advanced glycation end product. And that, sometimes, is still just an adduct, a thing hanging off the amino acid – but sometimes it’s not. Sometimes it’s a cross-link.

What happens is that typically, in structures such as the lens of the eye, you’ve got this protein which is undergoing this chemical reaction - and it is sitting next to another protein – and an actual chemical bond is created between one protein and another. Now, the elasticity of the whole lens structure relies on these proteins being able to ‘slide’ against each other – so suddenly, they can’t slide any more. And if elasticity is a prerequisite for the proper functioning of the tissue, then problems start to occur.

Of course, the elasticity of the lens of the eye is not a life threatening problem – not for us anyway – although it might be different if you were an animal being chased by a predator. For us, the walls of arteries are an example of where cross-linking takes place, and which does matter a lot.

I understand that you’ve written new book which has recently become available.

That’s right, it’s called ‘Ending Aging’ and there have been one or two very good reviews – and no negative reviews! There aren’t many reviews at all from ‘proper’ academics – and this is no surprise. The same thing applies here as has done with all the things I’ve been saying in the literature and talks and so on. Because I’ve essentially invented a new field – putting all of these different strands from disparate areas of biology together into a way of combating aging. Basically nobody else has the expertise in order to give an expert judgement on the validity and the possibility of all these things. So nobody wants to go near it really!

You mean in terms of expressing a dissenting opinion?

Yes! Especially because those who expressed negative opinions a few years ago got so extraordinarily stuffed – by my calling their bluff basically…