A day does not go buy without a patient asking about stem cells. President Bush made this a topic of national concern in August of 2001 when he limited federal funding on embryonic stem cell lines. This action led to much disarray within the science community, only now righting itself from that experience. We now have several sources of similar- but not identical- stem cells, and it is still an open question just how to make use of the information within stem cells to repair tissues in the living body.
One of the more recent developments has been the ability to “induce” stem cells from mature adult cells. this is done by administering a reprogramming “cocktail” that acts upon the DNA of the cell within the nucleus. Think of it as converting a cell backwards in time, to the point where it was not specialized. We do not know with certainty what the implications of this technique might mean down the road. Nevertheless the concept of re-programming is seductive and will no doubt be a hot topic over the next decade.
Before this type of technology is used in a human there are many obstacles to overcome. For this reason, expect to see “stem cell trials” in patients who really are in dire straits; paralysis of the spinal cord, or a fatal disease. Of course, this makes the burden of proof very high, but many authorities are comfortable in allowing the risk only in such situations. Unless there is a miraculous effect of such treatment, it is possible that the results may be ambiguous and open to interpretation.
In terms of cartilage repair, we know that stem cells under the influence of well known growth factors produce lots and lots of new cartilage. What we don’t know is that this can be done safely. The regulatory agencies are likely to demand a very significant research program, costing tens of millions of dollars, before any kind of a human trial would be allowed. A company would have to have deep pockets in order to be set upon this course. It may be more practical to await pioneering studies in other diseases in order to prove, in principle, that stem cells make sense as a clinical product. One thing is for sure- the manipulation of stem cells in the lab will continue to be a fruitful source of new science in the field of regenerative medicine.