Stem cells could be applied in various ways to medicine. Three of the potential uses of stem cells are outlined in Figure 2 (bottom of page). The first is the efficient creation of various specialized cells in order to treat diseases that are caused by the lack of only a few cell types (Univeristy of Wisconsin-Madison, Embryonic stem cells, 2006). Parkinson’s disease is due to a lack of dopamine-producing neurons. Scientists have been able to differentiate human stem cells into cells similar to these neurons. If they could improve the process they would be on the way to using stem cells as a treatment for Parkinson’s. This has been successfully applied in mice with Parkinson’s and the mice showed higher dopamine levels and improved movement. People suffering from type I diabetes could have insulin-creating cells implanted. Cardiac muscles could be repaired after a heart attack. (NIH & DHHS, Stem cell basics, 2006) Skin cells could be created to treat burns without directly taking skin from the victim (Univeristy of Wisconsin-Madison, Embryonic stem cells, 2006). There is also potential to treat other diseases and injuries such as Alzheimer’s, spinal cord injuries, stroke, osteoarthritis, and rheumatoid arthritis (NIH & DHHS, Stem cell basics, 2006).
Bone marrow transplantation is a form of stem cell treatment that is
already in
widespread use (Harvard Stem Cell Institute, 2005). It may also be
possible to
use bone marrow to regenerate heart tissue, which has been
successfully shown in
mice (NIH & DHHS, Stem cell basics, 2006).
There is the possibility of injecting stem cells into a developing fetus, as
illustrated in Figure 1, to
treat genetic disorders. This would avoid immune
rejection of the stem cells since the fetus does not have a fully developed
immune system. It could help in
diseases such as sickle cell anemia, severe
combined immunodeficiency syndrome,
and many metabolic diseases. The
outcome would depend upon the severity of the
individual disease. The
injection of hematopoetic stem cells into fetal lambs
and monkeys has been
shown to build a healthy colony of stem cells in the bone
marrow. Also, this
technique has been applied in the case of a few human
diseases. (University
of California, San Francisco, 2006)
Another application of stem cells is the possible use of the cells in drug testing. Different specialized types of cells could be created to quickly test chemicals for use in drugs (Univeristy of Wisconsin-Madison, Embryonic stem cells, 2006). The stem cells could also provide human cells which are currently unavailable from other sources, such as the cardiac muscle cells illustrated in Figure 2. Heart cells are not obtainable so heart drugs are tested on animals before the final test on human subjects. However the animal heart is not the same as the human heart. There have been deaths in human testing because a drug which was not toxic to any animal had adverse effects on the human heart. The use of stem cells to create heart cells for drug testing would hopefully prevent these situations. (Yu & Thomson, 2006)
Stem cells are also useful in providing a good way to research the development of the human fetus. They are a much easier way to study human embryo development than is possible through study a fetus in the uterus, or study fetuses of other animals. More knowledge on the development of the human fetus could help in treatments of birth defects, infertilitly, and pregnancy loss. (Univeristy of Wisconsin-Madison, Embryonic stem cells, 2006)
