Wednesday, February 17, 2010

Telomeres and aging

Recently I became aware of Sierra Sciences, a startup founded by William Andrews, previously of Geron. Andrews had done a lot of research on telomeres and telomerase.

Your cells have nuclei in them where your DNA is wadded up into packets called chromosomes. On the ends of the DNA strands there's a thing called a telomere. It protects the DNA from unravelling, like the little plastic tube on the end of your shoelace. Our telomeres shorten as we get older, and longer telomeres are strongly correlated with youth and vigor and health. There are many contributors to ageing but telomere length is currently regarded as one of the most urgent and one of the best understood.

Our reproductive cells do not suffer this effect. If we passed on shorter telomeres to our kids, they wouldn't live long, and they probably couldn't have kids of their own. To accomplish this, our reproductive cells produce stuff called telomerase which protects the telomeres from shortening. Here's the cool part: the gene for producing telomerase is present in ALL our cells, but it's only switched on in the reproductive cells. So there's a research push to find a telomerase activator that switches on the gene in all our cells. Sierra Sciences is one of the companies involved in this research.

You can buy a telomerase activator today, called TA-65. It's expensive, about $1500 per month, I think. But I haven't yet found any compelling evidence that it's a scam or a significant health risk. So I'm toying with the idea of trying it for a few months and see if I feel any different.

There is also a clinical test to measure the length of your telomeres. I know it exists but I don't know much more about it at the moment.


amiya said...

Hi Will,
Before experimenting with telomerase, please know that it can cause cancer!

Will Ware said...

Thanks for your concern Amiya, I had been aware of that issue. The folks most loudly pitching this idea are Sierra Sciences. They have a webpage saying:

In most cases (85–95%), cancers accomplish this indefinite cell division by turning on telomerase. For this reason, forcing telomerase to turn off throughout the body has been suggested as a cure for cancer, and there are several telomerase inhibitor drugs presently being tested in clinical trials.

So, anti-aging scientists must be out of their minds to want to turn the telomerase gene on, right?

No! Although telomerase is necessary for cancers to extend their lifespan, telomerase does not cause cancer. This has been repeatedly demonstrated: at least seven assays for cancer have been performed on telomerase-positive human cells: the soft agar assay, the contact inhibition assay, the mouse xenograft assay, the karyotype assay, the serum inhibition assay, the gene expression assay, and the checkpoint analysis assay. All reported negative results...

Paradoxically, even though cells require telomerase to become dangerous cancers, turning on telomerase may actually prevent cancer. This is not just because the risk of chromosome rearrangements is reduced, but also because telomerase can extend the lifespan of our immune cells, improving their ability to seek out and destroy cancer cells.

And they cite some papers:

Jiang, X.-R. et al. Telomerase expression in human somatic cells does not induce changes associated with a transformed phenotype. Nature Genet., 21, 111–114 (1999)

Morales, C.P., et. al. Absence of cancer-associated changes in human fibroblasts immortalized with telomerase. Nature Genet., 21, 115–118 (1999)

Harley, C. B. Telomerase is not an oncogene. Oncogene 21(4): 494-502 (2002).

Of course, their business model requires that they take this position, so their objectivity is a bit in question. I'm not financially prepared to do anything with the idea anyway, TA-65 is quite expensive. I'll probably have plenty of time to research it before I get to that point. At a minimum I'd talk to my doctor first.

bww said...

Hi Will!! Andrews has partnered with john Anderson and formulated Product B!!Check it out-
get back to me Byron