UMBILICAL CORD BLOOD
Lay Review

      Tremendous efforts have been dedicated into locating various sources of stem cells in the body because of their ability to self replicate or “differentiate” into other various tissues or cells (e.g. neurons, heart cells, islet cells of the pancreas that create the body’s insulin).  Stem cells are suggested to be located everywhere in the body, so it is without exemption that the Umbilical Chord Blood (UCB) does display these exceptional cells.  What is surprising though is that UCB stem cells display rather unique properties.  These cells are usually discarded soon after child birth, but research is focused on exploring umbilical cord blood’s therapeutic potential. .The stem cells found in UCB have shown the potential to differentiate into blood cells and immune cells as research is exploring the possibility of deriving other types of cells in the body from UCB stem cells.

      Currently, the therapeutic benefit of umbilical cord blood is that its transplantation can help patients that have a disease of their blood-producing organ. The center for blood production is within the bone marrow where hematopoetic stem cells (HSCs) reside and differentiate into the various blood and immune cells. Before the advent of umbilical cord blood transplantation, patients with diseases that affected blood production (i.e. hematopoietic disease) required bone marrow transplantation from a related or unrelated donor. Bone marrow transplantation is not always a successful solution for patients due to some drawbacks.

      Before bone marrow transplantation can even occur, patients are placed on a waiting list to find a matching bone marrow host. This process can take months and sometimes a match may not even be found. In the event of matching and successful transplantation into the patient there are additional hurdles. Screening bone marrow from donors for a match is necessary because the transplantation of non-matched cells from another person would be recognized as something foreign in the host (i.e. the patient). In response, the host’s immune system would attack the transplanted bone marrow and lead to what is known as Graft vs. Host Disease (GVHD) (Grewal, Barker et al. 2003). There are also other complications such as possible transmission of infectious agents (e.g. virus) from the donor to host, and the procedure of extracting bone marrow from the donor is an invasive surgery that causes the donor discomfort. These drawbacks of bone marrow transplantation make umbilical cord blood transplantation an attractive alternative in treatment for hematopoietic diseases.

      Umbilical cord blood is easily obtainable without being harmful to anyone, including the baby, by extracting blood with a syringe from the umbilical cord after the cord is cut from the newborn. The availability is also very high considering every live birth is technically a potential donor (Chao, Emerson et al. 2004). There are currently public and commercial umbilical cord blood banks that offer to cryogenically preserve the blood for future use. The banked blood can be used to be transplanted back into the individual from whom the blood was originally extracted or can be available publicly by consent to patients that suffer from a hematological disease. In the former case, the blood would be immediately available since it is banked and there is no need for matching since the blood is of the patient’s own. In the latter case, transplanting umbilical cord blood cells from one individual to another, umbilical cord blood has less stringent matching requirements compared to bone marrow transplantation (Ballen 2005). Therefore, the event of GVHD is less frequent. In the event of a GVHD event in the host, it is less severe, thereby more manageable, than in bone marrow transplantation.

      The first successful umbilical cord transplantation was performed in 1988 to help save the life of a six-year-old girl that was suffering from Fanconi anemia, which is a genetic disorder that leads to failure of bone-marrow function (Cohen and Nagler 2004). Since then, more than 4,500 transplantations have been performed worldwide (Copelan 2006; Goldstein, Toren et al. 2006). It is clear that umbilical cord transplantation has been well underway, but the research and the therapy are still in the relatively early stages of development. One of the current problems with umbilical cord transplantation is that there is a low stem cell yield per unit of umbilical cord blood. This decreases the chance of successful engraftment of the transplant in the host. Currently, researchers are trying to expand the number of stem cells in umbilical cord blood ex vivo (i.e. after the blood has already been extracted) to increase the chances of successful grafting (Grewal, Barker et al. 2003).

      The state of umbilical cord transplantation is continually evolving. With continuing scientific and community support, the research of umbilical cord blood can continue to help expand our knowledge of these stem cells and, subsequently, their application. Research is currently focused on attempting to differentiate stem cells found in umbilical cord blood into cells other than just blood cells. If this avenue shows success a dual advantage will result. There would be an alternative to embryonic stem cells for therapy and, as a result, the moral and ethical grounds that embryonic stem cell conflict with will not be breeched. Secondly, the successful differentiation of umbilical cord blood cells could serve as a powerful tool to battle a wide-range of disease. It is truly exciting times for the battle against disease with the viable umbilical cord blood and other stem cell therapies on the horizon.

Works Cited

Ballen, K. K. (2005). "New trends in umbilical cord blood transplantation." Blood 105: 3786-92.
Chao, N. J., S. G. Emerson, et al. (2004). "Stem cell transplantation (cord blood transplants)." Hematology Am Soc Hematol Educ Program: 354-71.
Cohen, Y. and A. Nagler (2004). "Umbilical cord blood transplantation--how, when and for whom?" Blood Rev 18: 167-79.
Copelan, E. A. (2006). "Hematopoietic stem-cell transplantation." N Engl J Med 354: 1813-26.
Goldstein, G., A. Toren, et al. (2006). "Human umbilical cord blood biology, transplantation and plasticity." Curr Med Chem 13: 1249-59.
Grewal, S. S., J. N. Barker, et al. (2003). "Unrelated donor hematopoietic cell transplantation: marrow or umbilical cord blood?" Blood 101: 4233-44.