Biomedical Engineering Reference
In-Depth Information
Chapter 5
Cord Blood Stem Cells
Not everything that can be counted counts,
and not everything that counts can be counted.
- Albert Einstein
Like bone marrow, umbilical cord blood is another rich source of hematopoietic
stem cells, being less mature than those found in the bone marrow of adults or
children.
Advantages
: The advantages of using cord blood as a source of stem cells are: its
noninvasive procurement and its vast abundance. Therefore, cord blood is world-
wide collected and either banked in public banks for general use, or stored by pri-
vate companies for private use. Cord blood has recently emerged as an alternative
source of hematopoietic stem cells for treatment of leukemia and other blood disor-
ders. The notable advantage of this application is that despite its high content of
immune cells, it does not produce strong graft-versus-host disease. Therefore, cord
blood grafts do not need to be as rigorously matched to a recipient as bone marrow
grafts [
1
]. This expands the available donor pool for hematopoietic stem cell trans-
plants considerably. Cord blood cells are more abundant than bone marrow cells
and are easier to collect than bone marrow. Collecting and storing of one's own
baby's cord blood stem cells does not present an ethical dilemma because they come
from the umbilical cord after delivery of the baby. Finally, cord blood collection is
painless, noninvasive process.
Disadvantages
: However, a disadvantage, and an argument against generalized use,
is the limited number of stem cells in any given cord [
2
]. A typical cord blood har-
vest only contains enough stem cells to transplant a large child or small adult
(weighing approximately 100 pounds). This is critical for the risk of graft failure
once transplanted into an adult. Because the stem cells in the cord blood are more
primitive than those in the bone marrow, the engraftment process takes longer with
cord blood, leaving the patient vulnerable to a fatal infection for a longer period of
