Using Stem Cells to Treat Disease
If scientists can ultimately learn how to direct stem cells to differentiate into one type of tissue or another, they can use them for two very important medical purposes.
 Photo courtesy University of Wisconsin Board of Regents Culture trays containing human embryonic stem cells are viewed under a microscope in developmental biologist James Thomson's research lab at the University of Wisconsin in Madison |
First, pluripotent stem cells can be used to test new medications for safety and effectiveness. A medication could be tried out on a specific type of cell to gauge its response far more quickly than it could be tested in clinical trials. For example, scientists could use a cancer stem cell line to investigate whether a new anti-tumor drug stopped the cancer from growing.
Stem cells could also be used to repair cells or tissues that have been damaged by disease or injury. This type of treatment is known as cell-based therapy. One potential application is to inject embryonic stem cells into the heart to repair cells that have been damaged by a heart attack. In one Mayo Clinic study, researchers induced a heart attack in rats, then injected rodent embryonic stem cells into the damaged hearts. Eventually, the stem cells regenerated the damaged muscle tissue, improving the rats' heart function.
Stem cells may also one day be used to repair brain cells in patients with Parkinson's disease. Parkinson's patients are lacking the cells that produce a chemical messenger called dopamine. Without dopamine, their movements become jerky and uncoordinated, and they suffer from uncontrollable tremors. In studies, researchers have injected rodent embryonic stem cells into the brain of rats with Parkinson's disease. The stem cells generated dopamine-producing nerve cells, improving the rats' condition. Scientists hope they can one day replicate their success in human patients.
Eventually, scientists might even be able to grow entire organs in a laboratory to replace ones that have been damaged by disease. The idea is this: They would create a sort of scaffold out of a biodegradable polymer to shape the organ, and then seed it with either embryonic or adult stem cells. Growth factors specific to the organ would be added to guide the organ's development. The tissue-covered scaffold would then be implanted into the patient. As the tissue grew from the stem cells, the scaffold would degrade, leaving a complete ear, liver or other organ.
Some of the diseases that may one day be treated with cell-based therapy are:
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Former First Lady Nancy Reagan also became an advocate for stem cell research when her husband, former President Ronald Reagan, was stricken with Alzheimer's, another degenerative brain disease. He died of Alzheimer's in the summer of 2004. |
