Saving Superman:
A Look into Stem Cell Research

While scientists continue to try and isolate other adult stem cells (multipotent cells) in the body, the greatest potential seems to lie in embryonic (pluripotent) stem cells.  This research will allow for the following:

• Pluripotent stem cell research will allow scientists to study factors involved in cell specialization, which is needed if stem cells can be used therapeutically.  Scientists will need to know how to direct a stem cell to function specifically as a heart cell, liver cell, neuronal cell, etc.  This regenerative therapy could solve the transplant supply shortage problem in hospitals.
   
• By studying normal cell specialization, scientists will gain insight into the specific causes of diseases, which are most often the result of abnormal cell division and/or cell specialization.  Although animal testing is helpful, it cannot always reveal the exact pathology and etiology of human disease.
   
• Human pluripotent stem cell research could change pharmaceutical drug testing.  All drugs go through extensive trials before being tested on humans or getting FDA approval.  Pharmacologists could use human stem cell lines to test drugs, which could decrease animal testing and prove safer for human trials.  This would reduce costs and streamline the approval process.
   
• Stem cells could be directed to function as heart cells to replace those damaged in a heart attack.

A recently raised issue facing researchers is whether adult stem cells (multipotent) can in fact be directed to specialize into various different cell lines like pluripotent cells can.  If so, this could sidestep several ethical issues and perhaps make Reeve's dream of walking again a reality.  Also, since the multipotent cells would come from Reeve's own body, they would not be rejected during transplantation.

Several studies thus far have led researchers to believe adult stem cells can indeed be manipulated like embryonic stem cells.  NIH researchers injected adult bone marrow stem cells into areas of the heart damaged by heart attack in mice.  Newly formed heart tissue occupied 68% of the damaged ventricles nine days after transplantation, suggesting that the bone marrow cells specialized into heart muscle cells.  Researchers at Duke University Medical Center have shown that adult liver stem cells responded to the tissue microenvironment of the heart in mice to repair damaged heart muscle.  University of Minnesota Stem Cell Institute researchers, headed by Dr. Catherine Verfaillie, transplanted adult bone marrow stem cells from rats and humans into mice and found that the cells differentiated according to their environment.  For example, if they were injected into the liver, lung, or stomach, they specialized into those cell types.  Also, the stem cells did not divide uncontrollably.  Verfaillie and her colleagues believe that selected adult bone marrow stem cells can act as multipotent adult progenitor cells (MAPCs), meaning they are as versatile as embryonic (pluripotent) stem cells and can be manipulated to the same extent.

Concept Check:

1. Some of the current drawbacks of drug testing include: (a) expense, (b) the issue of animal testing, (c) risk in human trials, and (d) delayed FDA approval.  How could stem cell use potentially improve this process?
2. Why is it critical that scientists effectively control stem cell division?
3. Why is the finding by Dr. Verfaillie and her colleagues significant? 
4. Potentiality is a complex issue.  Do you think stem cell research serves as a potential for human healing or a way to perhaps create a real Superman?  Is there a way to find a common ground and protect public health while respecting all opposing views?

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