2012年9月23日 星期日

Stem Cells May Make Many Lifesaving Treatments Possible - Much Work Needs to Be Done


Researchers reported on the new ability to reprogram adult human skin cells a little more than two years ago. This remarkable breakthrough has led to great excitement and anticipation, as well as ongoing investigations to help make regenerative medicine a reality. Important new developments are being published almost every month and the field is moving very fast.

Up until very recently everyone "knew" that adult cells had permanently lost their ability to return to a primitive state, i.e., lost their ability to transform into any other kind of cell. Everyone "knew" that once a cell differentiated into a particular lineage and cell type, that was it. In the words of the Bones characters Agent Seeley Booth and Dr. Temperance Brennan, there are "no do-overs" and "no take-aways" in embryology.

Almost none, that is. For example, adult bone marrow cells retain a multipotent ability. Throughout life, these cells transform into red blood cells, platelets, and many types of white blood cell. But this understanding has been shown to be insufficient. In fact, adult bone marrow cells have more than multipotent abilities. They are able to transform into brain cells under the right conditions, and may eventually be proved to be pluripotent.

Throughout the 20th century, schoolchildren, high schoolers, and college students learned that cellular differentiation is a permanent event. No do-overs. In 2007 visionary scientists proved that this "well-known fact" was incorrect. Adult human cells, specifically skin cells, are able to be reprogrammed back to an initial state. Reprogramming returned to these cells the ability to differentiate (transform) into any other kind of cell.

It's so easy to leap ahead and consider what might become possible. Healthy cells, tissues, and organs - tailored to a specific person - might be produced from a simple skin biopsy. Cures might become available for devastating diseases. Many people around the world might be helped to live longer, healthier lives. But much knowledge remains to be acquired and many genetic, immunologic, and biochemical challenges will need to be overcome before the first treatment for any disease is actually delivered to a patient.

The field of gene therapy provides a seriously cautionary tale. Fifteen years ago many scientists, as well as science experts in the popular press, believed that gene therapy was around the corner. The Human Genome Project was well underway and researchers had begun to identify a few DNA locations that were associated with specific genetic diseases. A few potential treatments were rushed into clinical trials. A catastrophic result soon obtained - the death of a Pennsylvania teenager who was a subject of one such trial. The field ground to halt as the FDA launched an investigation. It has taken many years for gene therapy to recover as a reputable discipline. Clinical trials for various therapeutic uses of reprogrammed pluripotent adult human cells will only take place after many years of further investigation and research.




David Lemberg, M.S. in Bioethics, Albany Medical College, May 2010 Consultant, Author, Speaker. Research interests - health care and health care policy, reproductive technologies, genetics and genomics, K-12 science education Executive Producer, SCIENCE AND SOCIETY, http://scienceandsociety.net Twitter - http://twitter.com/david_lemberg Visit SCIENCE AND SOCIETY for cutting-edge interviews with Nobel Laureates, trendsetting industry executives, and best-selling authors in the fields of cancer research, genetics, health care policy, nanotechnology, and space exploration.





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