APPLICATION OF STEM CELLS IN ISCHEMIC HEART DISEASE - Micro and Nanotechnologies in Engineering Stem Cells and Tissues - page 290

TABLE 12.9 ( Continued )

Cell Type Source Advantages Limitations

immune-suppression
treatment
6. Can improve myocar-
dial contractile
function

Embryonic
stem
cells

Allogenic blastocyst
(inner mass)

1. Easy propagation and
well-defined cardio-
myocyte differentia-
tion process
2. In vivo electrical cou-
pling of transplanted
cells to existing myo-
cardial cells
3. Pluripotent cells

1. Potential for tumor for-
mation and immune
rejection (allogenic)
2. Incomplete response to
physiological stimuli

3. Legal and ethical
issues
4. Donor availability

Source: Adapted from Ref. [17].

cell activity in the environment of chemokines and growth factors. Both factors
induce the migration of stem cells; however, growth hormone appeared to be more
effective. In particular, PDGF-AB, TGF- b 1, TNF- a were exposed to growth

hormones to observe the active migration of stem cells.
Interestingly, the factors that enhance themigration of stemcells exhibited improve-
ment when used to stimulate stem cells. Among these factors, TNF-

showed the best
response from stem cells. It was confirmed that stem cells' homing effect improved up
to 4.4 times when stimulated by chemotactic chemokines and growth hormones.

a

12.6.5 Shortcomings in Stem Cell Applications

Use of ESCs for research involves the destruction of blastocysts formed from
laboratory-fertilized human eggs. For those who believe that life begins at concep-
tion, the blastocyst is a human life, and to destroy it is unacceptable and immoral.
The range of different types of cells that stem cells can change into may be limited
to a set of cells that may not be useful for certain diseases. The complexity of
individual diseases will govern whether stem cell therapy is applicable.
Another possible restriction is the problem of tissue rejection when stem cells
from other sources are used to treat a person who is tissue incompatible. This is a
situation in which adult stem cells from the patient could have great use because they
would not be recognized as foreign by their body.
Use of stem cell lines from alternative nonembryonic sources has received more
attention in recent years and has already been demonstrated as a successful option for
treatment of certain diseases. For example, adult stemcells can be used to replace blood
cell-forming cells killed during chemotherapy in bone marrow transplant patients.