Rejuvenation Research for August 2008
The latest issue of Rejuvenation Research (volume 11, number 4) is available online. As usual, the contributions come from a broad range of fields in the life sciences applicable to extending healthy life span and repairing the damage of aging. Here are a couple of examples that focus on the nuts and bolts of pushing aging cells to perform greater feats of regeneration:
What is the relationship between stem cell aging and organismal aging? Does stem cell aging cause organismal aging or vice versa? Will stem cell aging aggravate age-related diseases? And what is stem cell aging?As suggested herein, hyperstimulation of signal transduction pathways can render cells compensatorily irresponsive. And the hallmark of stem cell aging is poor responsiveness to activating stimuli. On the basis of the hypothesis that insensitivity to stimuli is in part due to hyperactivation of the target of rapamycin (TOR), this article suggests a means of pharmacologic rejuvenation of stem cells and wound-healing cells.
This is a useful way of looking at the issue of aging stem cells. I'm not sold on the specific details - the focus on TOR - but the general strategy of exploration and experimentation with stem cell response sounds good. If the cells are still good to go, a great deal of good might be accomplished with some comparatively simple targeted manipulations.
By way of an aside, you might recall that TOR is associated with the biomechanisms of calorie restriction, but then it's one of the pathways associated with everything of importance in the realm of metabolism.
Host Cell Mobilization for In Situ Tissue Regeneration
The goal of the present study was to investigate whether host biologic resources and environmental conditions could be used for in situ tissue regeneration, which may eliminate the need for donor cell procurement and subsequent in vitro cell manipulation. To address this aim, we implanted a common biomaterial into mice and characterized the infiltrating cells to determine their regenerative potential....
the infiltrating cells are capable of differentiating into multiple cell lineages, including osteogenic, myogenic, adipogenic, and endothelial lineages, if appropriate conditions are provided. These results suggest that it is possible to recruit a predominance of cells with multilineage potential into a biomaterial scaffold. Therefore, it may be possible to enrich the infiltrate with such cell types and control their fate, provided the proper substrate-mediated signaling can be imparted into the scaffold for in situ tissue regeneration.
Which is a rather long-winded way of saying that suitably designed nanostructures and control over stem cell signaling should be able to replace first generation cell delivery therapies in many situations. In theory, medical science could move the apparatus of programming and activating stem cells entirely inside the body - no need to pull cells out for culturing and manipulation or find transplant sources. It's a promising vision.
Certainly in situ regeneration therapies will be cheaper than regeneration therapies where cells must be removed, manipulated in a lab, then re-implanted back in the person.