Not all stem cells are alike. News to you? Maybe not, but it has hit researchers pretty hard over the past several weeks. As you may have garnered from prior essays on this blog, stem cells are potentially capable of morphing into many different tissues, such nerves, heart or liver, and are the next wave in medical therapy for all kinds of diseases affecting both the young and the old. The medical treatment that they will bring to the table is called “personalized, cell based therapy.”
One huge problem is that the best kind of stem cell, the one that can do the most, is created from embryos. The embryonic stem cell has many “issues” though: derived from embryos, retrieval ethics, not patient specific, created by cloning, inefficient to produce and the like. Because of this, research has focused on alternatives like transformed adult stem cells or our very own untransformed testicular stem cells. The news today concerns the quality of adult-type stem cells that are “reprogrammed” and transformed into embryonic-like stem cells, also termed induced pluripotency stem (iPS) cells.
Well, there appear to be growing pains for the iPS cell, an embryonic stem cell alternative. Developed in 2006 from adult skin cells, researchers genetically manipulated a specialized adult cell, transforming it back to an unspecialized state. Since then, hundreds of labs have leaped into the burgeoning adult stem cell field.
The ideal stem cell is like a blank slate. It is capable of becoming any other tissue, and is immortal. True embryonic stem cells are like this, but, according to several recent publications, many iPS cell lines are not really blank slates. Also, it appears that nerve and blood cells made from iPS cells grow poorly and age quickly and may even “remember” what cell from whence they came. Some even conclude that iPS cells may not even be considered a practical choice for cell-based therapy down the line.
The realization that iPS cells are not exactly like the gold standard embryonic stem cells has slowed the field down a bit, but it is an important observation. Like people or even wine, stem cells are a bit different from one another, each with their own personality, temperament and potential. Some do this better than that, and others do that better than this. It suggests that stem cell-based therapy may eventually involve tapping into a mixture of different stem cells to cure the problem. Now that’s an old fashioned idea: a little of this and a little of that…