Safety Issues in Stem Cell Transplants

Safety is the first factor to be considered when discussing the benefits of different types of stem cells.

Embryonic Cells

In addition to the moral and ethical issues involved with using embryos, embryonic stem cells have numerous challenges, including contamination, genetic instability and cancer risk. Some embryonic stem cell lines approved for research are no longer "pure" human lines since being exposed to mouse "feeder" cells to help keep them viable. The potency of these "older" approved cell lines is also increasingly compromised by time and proliferation. These cell lines accumulate genetic abnormalities as they replicate and their rapid replication with any genetic instability can create a risk of tumor development in both animal and human transplants.

For research on the challenges of embryonic stem cells, click here.

The major challenge with fetal cells as used in foreign countries, is risk of graft versus host disease. Stem cells and neurons may be contaminated with blood and other tissue cells which have developed immune defenses to "foreign" cells. These fetal cells may cause immune reactions and severe health problems in the patient receiving them. In addition, the use of cortisone products to reduce immune reactivity also promotes the production of glutamate. Elevated glutamate levels are toxic to neural stem cells and can compromise the effectiveness of treatments for brain injuries and disorders. For research on corticosteroids and neural toxicity, click here.

Over 5,000 cord blood transfusions, frequently in children with leukemia, have been successfully performed throughout the world with little or no side effects since 1988. Recent research has shown that primitive stem cells from umbilical cord blood have similar powers and health promoting benefits as do embryonic stem cells but without the ethical and safety issues.

Advances are being made each day in providing greater safety to the patient. New methods of separating the stem cells from other blood components have resulted in a product that consists of only stem and progenitor cells (differentiated stem cells). Since these umbilical cord stem and progenitor cells have not yet developed mature immune defenses (ABO and HLA antigens on their surfaces), they do not induce graft versus host reactions that may occur with differentiated embryonic stem cells or bone marrow stem cells. For information on reduced immune reactions with cord stem cells, please click here.

Larger doses of cord stem cells can also be given to further prevent immune reactions and increase effectiveness. A normal placenta and umbilical cord contains about 300,000 stem cells.

These 300,000 stem cells can be grown in tissue culture so as to reach over two million cells. These two million stem cells are used for one treatment. These increased numbers of stem cells significantly improve the results, especially in brain and spine injuries and disorders.

There are several ways that cord stem cells promote the growth of new brain tissue. Cord stem cells produce and stimulate the release of growth factors. Stem cells have been observed to fuse with established neurons as well as differentiate into neurons, astrocytes and glia cells.

For information on cord stem cells having the ability to differentiate into neurons, click here.

For information on neurological disorders that have improved with the use of umbilical cord stem cells, click here.

In addition, various pre- and post-treatment protocols are being evaluated to help maximize the effectiveness of cord stem cell treatments. If you'd like to be on our mailing list for updates on these evolving therapeutic programs, please click here.