Induced Pluripotent Stem Cells – A Potential Medical Holy Grail
Induced pluripotent stem cells (iPS cells) are the new kids on the block in the field of stem cell research. In 2007 two teams of investigators published groundbreaking news – both teams had reprogrammed adult cells, restoring their original ability to become any other kind of tissue.
Stem cells (SCs) are progenitor structures and are characterized as totipotent, pluripotent, and multipotent, based upon their abilities and potential. Totipotent cells are found in early-stage developing embryos. Up until the 8-cell stage, embryonic cells have the ability to develop into a complete organism. Each of these units, known as blastomeres, could be dissected away from the 8-cell mass, cultured in artificial media, implanted into a womb, and become a complete organism. Pluripotent cells are able to develop into any type of tissue, but are unable to develop into a complete organism. For example, pluripotent cells may develop into bone, nerve, muscle, cartilage, blood, liver, kidney, or skin. On the other hand, multipotent types can develop into various cells of a specific lineage. Multipotent connective tissue cells could become bone, cartilage, or muscle. Multipotent endodermal cells could become stomach, intestine, or gallbladder components.
Pluripotent SCs have, until very recently, been obtained from embryos or umbilical cord blood. The majority of SC research to date has been done on embryonic stem cells.
The medical benefits derived from stem cells could potentially impact every person on the planet. Heart disease and diabetes – leading causes of chronic disease and death in the United States – could be treated using tissues derived from SCs. Stroke patients could have brain tissue restored and revitalized. Parkinson’s disease, Huntington’s disease, and ALS (Lou Gehrig’s disease) could be successfully treated with disease-free nerve tissue derived from stem cells. Sickle cell anemia, thalassemia, and leukemia could all be successfully treated using the remarkable properties of SCs.
Of course, these powerful treatments all lie in the future. The types of research problems needed to be solved are numerous and complex. What’s critical is that the research goes forward. Herein lies the problem. Pluripotent SCs used in research have been derived from embryos. But the process of obtaining stem cells kills the embryo. This fact of embryo destruction creates substantial and severe ethical issues. These ethical concerns led to former President George W. Bush’s decision to allow federal funding of stem cell research on already existing stem cell lines. Federal funding to create new SC lines was prohibited.
This debate has raged for more than a decade. iPS cells, derived from adult cells, may provide a unique solution and allow important research to go forward. Such research would be ethically acceptable to all sides.