ADULT STEM CELLS

August 2004
		Adult stem cells, which come from bone marrow, skin, brain, blood and muscle, appear to have enormous potential to help repair the body. But individual studies on stem cell therapy are showing mixed results. Helen Blau, Ph.D., of the Stanford University School of Medicine and Charles Murry, M.D., Ph.D., of the University of Washington's Department of Pathology answer your questions.

Online NewsHour Special Report: Adult Stem Cells Forum Introduction If the current restrictions posed on stem cell research were eliminated, how long would it be before initial procedures for spinal cord injuries would begin to appear? I have Parkinson's and I'm 51 years old. What's a possible timetable for the application of stem cell therapy to help me and others in my age range? Why can't stem cells derived from bone marrow be cultured and the injected locally into regions of the brain that has been damaged as a consequence of a stroke? What are your feelings on the potential of umbilical cord blood as a source of stem cell transplantation? Is it true that the research to date is not applicable to all ethnic groups, particularly, persons of African decent? Can stem cells injected into the body cause cancers? What kind of research is happening in this country, and when can I see human research here?	Anthony Hammond of Spring Grove, Pa., asks: If the current restrictions posed on stem cell research were eliminated, how long would you estimate it would be before initial procedures for spinal cord injuries would begin to appear? Dr. Helen Blau responds: Although this is not my area of expertise, it seems that success to date suggests that Phase I trials could begin in one to five years. Dr. Charles Murry responds: Spinal cord repair with cells from adult neural stem cells and embryonic stem cells is underway in many laboratories. There is no question that the pace of research with embryonic stem cells would increase after lifting current restrictions. It is always difficult to predict when a change in research would effect a change in clinical practice. I would expect we'd see changes in clinical trials in five years (maybe less) if the restrictions were dropped today. For spinal cord repair, having the right cells is only part of the solution, however. Cells need to send wire-like extensions (axons) back through injured regions to re-establish connections. This can require growing several inches or more. Chemical signals from the injury can inhibit this process, resulting in a tangle of axons rather than orderly rewiring. We need to understand how the wound inhibits axon regrowth and how to control this process.