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What medical conditions might be affected by stem cell discoveries?

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[JULY 13, 2005]  BETHESDA, Md. -- Stem cell information from the National Institutes of Health (http://stemcells.nih.gov/info/faqs.asp):

Why are doctors and scientists so excited about human embryonic stem cells?

Stem cells have potential in many different areas of health and medical research. To start with, studying stem cells will help us to understand how they transform into the dazzling array of specialized cells that make us what we are. Some of the most serious medical conditions, such as cancer and birth defects, are due to problems that occur somewhere in this process. A better understanding of normal cell development will allow us to understand and perhaps correct the errors that cause these medical conditions.

Another potential application of stem cells is making cells and tissues for medical therapies. Today, donated organs and tissues are often used to replace those that are diseased or destroyed. Unfortunately, the number of people needing a transplant far exceeds the number of organs available for transplantation. Pluripotent stem cells offer the possibility of a renewable source of replacement cells and tissues to treat a myriad of diseases, conditions and disabilities, including Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.

Have human embryonic stem cells been used successfully to treat any human diseases yet?

Scientists have been able to do experiments with human embryonic stem cells just since 1998, when a group led by Dr. James Thomson at the University of Wisconsin developed a technique to isolate and grow the cells. Moreover, federal funds to support research with human embryonic stem cells have been available only since Aug. 9, 2001, when President Bush announced his decision on federal funding for this research. Because many academic researchers rely on federal funds to support their laboratories, they are just beginning to learn how to grow and use the cells. Thus, although human embryonic stem cells are thought to offer potential cures and therapies for many devastating diseases, research using them is still in its early stages.

Adult stem cells, such as blood-forming stem cells called hematopoietic stem cells in bone marrow, are currently the only type of stem cell commonly used to treat human diseases. Doctors have been transferring these cells in bone marrow transplants for over 40 years. More advanced techniques of collecting, or "harvesting," these cells are now used in order to treat leukemia, lymphoma and several inherited blood disorders.

The clinical potential of adult stem cells has also been demonstrated in the treatment of other human diseases, including diabetes and advanced kidney cancer. However, these newer uses have involved studies with a very limited number of patients.

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What will be the best type of stem cell to use for therapy?

Pluripotent stem cells, while having great therapeutic potential, face formidable technical challenges. First, scientists must learn how to control their development into all the different types of cells in the body. Second, the cells now available for research are likely to be rejected by a patient's immune system. Another serious consideration is that the idea of using stem cells from human embryos or human fetal tissue troubles many people on ethical grounds.

Until recently, there was little evidence that multipotent adult stem cells could change course and provide the flexibility that researchers need in order to address all the medical diseases and disorders they would like to. New findings in animals, however, suggest that even after a stem cell has begun to specialize, it may be more flexible than previously thought.

There are currently several limitations to using adult stem cells. Although many different kinds of multipotent stem cells have been identified, adult stem cells that could give rise to all cell and tissue types have not yet been found. Adult stem cells are often present in only minute quantities and can therefore be difficult to isolate and purify. There is also evidence that they may not have the same capacity to multiply as embryonic stem cells do. Finally, adult stem cells may contain more DNA abnormalities -- caused by sunlight, toxins and errors in making more DNA copies during the course of a lifetime. These potential weaknesses might limit the usefulness of adult stem cells.

I have Parkinson’s Disease. Is there a clinical trial I can participate in that uses stem cells as therapy?

The public may search a database of National Institutes of Health-sponsored clinical trials at http://www.clinicaltrials.gov. Enter the search terms of interest (in this case, "Parkinson's disease and stem cells") to search for applicable clinical trials.

Where can I donate umbilical cord stem cells?

The National Institutes of Health cannot accept donated umbilical cord stem cells from the general public. The National Marrow Donor Program maintains a Web page on donating cord blood, at  http://www.marrow.org/NMDP/
cord_blood_bank_list.html
, and the International Cord Blood Society has one at http://www.cordblood.org/public/insights.

[National Institutes of Health]


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