A comment on yesterday's post on advances in stem cell infrastructure technologies:

Great news, but I have this question: what possible reason or mechanism exists for assuming that an "induced" stem cell created from an already aged cell wouldn't get some of the induced damage carried along with the machinery? I can't see how this would be a 100% "reset".

Still, I imagine even a slightly pre-aged replacement organ from your own cells would be a helluva a lot better than a foreign transplant with rejection problems.

Here's another one - if you're replacing an organ or tissue because of genetic disease, how long before the newly constructed replacement would start to fail in the same way?

Which is true; a new organ grown from your own tissue is not an automatic benefit under all circumstances. However, I see the building of new organs from small numbers of stem cells as just one component of what can potentially be achieved when you can create new pluripotent stem cells to order. There is a point early in the process at which you are working with just a handful of cells, freshly extracted. There, the opportunity exists to economically apply any form of new technology aimed at manipulating, repairing or changing those cells prior to growing new tissue.

For example, lengthening telomeres, or correcting simple genetic errors. These are things that can be done today in a limited fashion - we don't fully understand the consequences, and our knowledge is small in the grand scheme of things. That won't always be the case, however, and this point of opportunity in the growth of new tissue tailored for the individual will remain as we find new and better ways to take advantage of it.

The damage of aging in our cells is "just" a wrong arrangement of molecules, when it comes down to it. It seems plausible that selecting the least damaged cells, or repairing specific forms of damage - such as replacing age-damaged mitochondria with freshly repaired versions - is a near-future approach to minimizing the damage of aging in induced pluripotent stem cells.

One caveat: it looks likely that the behavior of stem cells, or any new tissue, in the body has a great deal to do with the holistic functioning of signaling networks and the cellular environment. You can't just take the cells in isolation when thinking through potential technologies and applications - you have to consider the aged environment of the surrounding tissue.

In general, there is a great deal of good that could be achieved with the technology to create pluripotent cells from any cell - and many other lines of research that can be applied atop this foundation with the goal of building better, less damaged tissue from aged cells. Beyond that, who knows? At some point we'll be skipping the extraction of cells and just building them outright from raw materials - and around about there aging becomes somewhat moot, given the biotechnoloy that implies.

Posted by Reason at February 12, 2008 8:33 PM | TrackBack (0)