Next week, more than 1,200 people from 25 countries are expected to attend the 8th Annual World Stem Cell Summit in West Palm Beach, Fla., a gathering co-sponsored by Mayo Clinic. As those close to the science explore potential stem cell applications, many patients have questions about what stem cells are and how they are being used. Timothy Nelson, M.D., Ph.D., director of Mayo Clinic's Regenerative Medicine Consult Service, answers some of the most commonly asked questions about stem cells:
What are stem cells?
Stem cells are the body's raw materials. These cells have the ability to renew themselves or change to become specialized cells with a more specific function, such as blood cells, brain cells, heart muscle or bone.
Where do stem cells come from?
•Adult stem cells are found in tissues of the body, such as bone marrow. Emerging evidence suggests that adult stem cells may be more versatile than previously thought and have the ability to create other types of cells.
•Amniotic fluid stem cells come from the liquid that surrounds a developing fetus in the amniotic sac. More study of amniotic fluid stem cells is needed to understand their potential.
•Embryonic stem cells are a general stem cell found in embryos. Use of this type of stem cell has significantly declined due to the discovery of induced pluripotent stem cells.
•Induced pluripotent stem cells, commonly known as iPS cells, are derived from an adult stem cell that behaves like an embryonic stem cell. This new technique may help researchers avoid the controversy that comes with embryonic stem cells and prevent immune system rejection of the new stem cells.
•Mesenchymal stem cells are adult stem cells found in tissues such as bone marrow, blood and the fallopian tube. They can become bone, cartilage, fat and possibly other cells.
How are stem cells being used to treat diseases?
Stem cell transplants, also known as bone marrow transplants, have been performed in the United States since the late 1960s. These transplants use adult stem cells.