Though governments may adopt conservative views about funding stem cell research, there are increasing signs that they may not be able to stop research as stem cells are increasingly yielding a panacea to many of world's health problems. The latest research findings funded by the Christopher Reeve Foundation suggest that human stem cell injections can repair damaged spinal cords in mice, permitting them to walk again.
The results of an experiment reported yesterday are also not the first to demonstrate the tantalizing hope that stem cells offer in the arena of spinal damage treatment. The new study however goes the extra mile in suggesting that the stem cells form connections that are key to the recovery of damaged spines. In the study scientists found that the ubiquitous stem cells also formed the sheath of cells that insulated the nerve fibers they had earlier formed, facilitating nerve fiber communications. With several of the movement limiting diseases such as multiple sclerosis arising out of loss of the insulating myelin sheath this form of treatment seems a ray of hope for affected patients.
The stem cells augured as the building blocks of life, by developing into different types of tissue, have been hailed as modern medicine's hope to many human problems. Scientists have been particularly interested in harnessing embryonic stem cells for regenerating damaged organs and body parts as they serve like blank slates that can be bio-chemically stimulated to turn into a tissue of choice.
Aileen Anderson of the University of California, who lead the research while expressing her excitement about the possibilities afforded by stem cells said, "The actual cells that we transplanted, the human cells, are the ones that are making myelin". Published in the current issue of Proceedings of the National Academy of Sciences, the study involved researchers injuring the spines of mice and injecting some human neural stem cells nine days later.
Anderson and her team in using fetal neural stem cells that are bit more developed than the usual embryonic stem cells, gave the mice a better chance of recouping given that these cells were anyway destined to form parts of the central nervous system. In just four months, the treated mice were able to step normally on their hind legs unlike mice that were not given any treatment or treated with unrelated cells.
Trying to resolve whether the injections of stem cells itself stimulated the healing or whether they participated in healing and repairing process itself, Anderson's team tried to achieve the same results with diphtheria toxin that does not attack mouse cells and found that the improvements disappeared. This clearly was suggestive of the cells themselves having a "striking" role in the repair and recovery of the damaged nerve tissues. Also a closer analysis of mouse spinal cords indicated that some of the human stem cells had turned into nerve cells, but the bulk had formed oligodendrocytes that form the myelin sheath, key to neurotransmission of electrical signals.
But clearly more research is necessary before stem cells can yield similar results in humans by curing spinal injuries. A question that research leaves is when after injury should cells be administered to yield positive results and how significant is nine days in a mouse's life. Given that the test mice were specially bred to be resistant to auto-immune reactions to human cells, it does not resolve the risks of transplant rejection in humans. But as Anderson put it, "The exciting part is the potential is there" and probably just needs a little further study.
