A small company called BioTime has gotten a lot of attention in the last couple of days after a press release about cellular aging. To give you an idea of the company's language, here's a quote:

"Normal human cells were induced to reverse both the "clock" of differentiation (the process by which an embryonic stem cell becomes the many specialized differentiated cell types of the body), and the "clock" of cellular aging (telomere length)," BioTime reports. "As a result, aged differentiated cells became young stem cells capable of regeneration."

Hey, that sounds good to me. But when I read their paper in the journal Regenerative Medicine, it seems to be interesting work that's a long way from application. Briefly - and since I Am Not a Cell Biologist, it's going to be brief - what they're looking at is telomere length in various stem cell lines. Telomere length is famously correlated with cellular aging - below a certain length, senescence sets in and the cells don't divide any more.

What's become clear is that a number of "induced pluripotent" cell lines have rather short telomeres as compared to their embryonic stem cell counterparts. You can't just wave a wand and get back the whole embryonic phenotype; their odometers still show a lot of wear. The BioTime people induced in such cells a number of genes thought to help extend and maintain telomeres, in an attempt to roll things back. And they did have some success - but only by brute force.

The exact cocktail of genes you'd want to induce is still very much in doubt, for one thing. And in the cell line that they studied, five of their attempts quickly shed telomere length back to the starting levels. One of them, though, for reasons that are completely unclear, maintained a healthy telomere length over many cell divisions. So this, while a very interesting result, is still only that. It took place in one particular cell line, in ways that (so far) can't be controlled or predicted, and the practical differences between this one clone and other similar cells lines still aren't clear (although you'd certainly expect some). It's worthwhile early-stage research, absolutely - but not, to my mind, worth this.