Studying stem cells will help us 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 successfully treated any human
diseases?
Scientists have been able to do experiments with human embryonic
stem cells (hESC) only 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 hESC
research have been available since only August 9, 2001, when
President Bush announced his decision on Federal funding for hESC
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 hESC 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 in bone marrow
(called hematopoietic stem cells, or HSCs), are currently the only
type of stem cell commonly used to treat human diseases. Doctors
have been transferring HSCs in bone marrow transplants for over 40
years. More advanced techniques of collecting, or "harvesting," HSCs
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 that include
diabetes and advanced kidney cancer. However, these newer uses have
involved studies with a very limited number of patients.

Participating in Research Studies
Scientists are testing the abilities of adult stem cells to treat
certain diseases. You can search for clinical trials using stem
cells (or other methods) to treat a specific disease at
ClinicalTrials.gov.