Hype and hope: stem cells in action

Inspiration comes from 3 interconnected posts of Bodyhack which is always well-informed and easy to catch.
First, a couple in South Africa has been arrested for allegedly charging desperate patients $24,000 for stem cell treatments for a once-off injection of 1.5 million stem cells. From the source: “Patients were also told that once injected, the stem cells migrated to the site of the disease and began producing the needed cells.”
Now homing is one of the hardest question of stem cell research, it seems that the stem cells’ innate ability to travel to the right place in the body is real but very restricted phenomenon, if you add 1.5 million cells (I did it many times in rat) systematically, only a very small fraction will dock properly, the rest will be eliminated or become problematic. And out the proper small fraction only a few cells will differentiate into the needed, functioning cells. We do not know the exact list of signals, which makes homing a safe and well targeted process.
Second, an encoded article says, that current stem cell research are moving away from using the cells as therapies, and rather use them as tools of disease exploration and drug development.
I would rather say that instead of direct in vivo stem cell transplantation (homeless stem cells), in vitro tissue engineering (stem cells with prefab home) seems now more promising as a future therapy. Stem cells are of course good models of diseases (hypoxia, oxygen-glucose deprivation, diabetes, CNS problems) and are very useful for developing drugs, but that does not mean a lesser therapeutic potential. The opposite is true, I suppose.
Third, Washington scientists with the help of the founding father Gage demonstrated in vitro, using cocultures of treated cells and degenerated mouse retinas, that human ES cells can be differentiated primarily into inner retinal neurons with high efficiency by using a combination of 3 growth factors.
As I see, these experiments are rather just promising preparations for an in vivo repair, because they based on cocultures in vitro. Looking forward to a successful in situ retinal repair with these differentiated hESCs in a real animal.

I think this panorama: a crime story, an opinionated publicism, and a scientific result is a rather typical snapshot of our stem cell driven present. So take a look at my tile scan picture of human stem cells, which is like a distant galaxy.