Regeneration: Success and Failure

Clinical studies have recently shed some light upon cell and growth factor studies for a variety of illness, including stroke, dementia and spinal cord injury, that will certainly advance our understanding of the potential for regenerative therapy and also point out the pitfalls in developing new treatments and delivery systems. In medicine, it is never enough to have a good theory, one must make it practical and reproducible as well- and commercially viable.

The ALDH stem cell trail for stroke, in which a special set of bone marrow derived stem cells was purified and injected into the artery that feeds the brain, showed good safety and no effect whatsoever in well compared groups of 25 patients and 25 controls. The FDA allowed for 100 patients in the trial, but the study was terminated early based upon lack of any clear response over and above what would be expected for no treatment. This is an excellent way to perform a study, and the negative result is quite useful; there is no evidence that injected stem cells “seed” or “engraft” the desired area, although it was hoped that they might secrete growth factors to help the brain heal itself. More science is needed about delivering cells to the target organ.

Another trial on spinal cord regeneration for paraplegia looks a bit optimistic in its early stages. Once again, the trick will be to get comparable groups of patients in order to convince ourselves that there is a real effect; when measuring very small but significant nerve return after complete paralysis, it is easy to fool yourself even with the best motives. So far, the cell therapy shows no adverse reactions, a good start.

Much in the news are studies from Harvard and UCSF on aging in mice. Some component in the blood serum of a younger mouse is capable to reversing nerve degeneration in the brain of an older mouse- and vice versa, perhaps! One group believes this blood component is precisely one of the powerful factors in PRP (TGF Beta)! Clearly, much work needs to be done to confirm this finding, to specify what is causing it, and to find out if it has applicability in other mammals. One interesting fact is that blood plasma is already “on the market”, so how interesting would it be to segregate blood donations by age and use just the plasma for regenerative purposes? Or of course to purify the protein(s) involved and to bioengineer them?

These concepts will proceed with fits and starts, and well done science will push the field forward, bit by bit.