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Stem Cell Basics
What are stem cells?
o unspecialized cells
o can become:
o
many different kinds of
specialized cells
What is differentiation?
What is differentiation?
unspecialized cell
ExStem cell
specialized cell
nerve
liver
heart cell
etc.
(3) Characteristics of Stem Cells
o Not differentiated
o for relatively long periods of time can keep
dividing -> unspecialized cells
(= long-term self renewal)
o With appropriate signal:
o
o
divide -> daughter cells
new daughter cells can differentiate
into specialized cells needed for growth and repair
What are some different kinds of
stem cells?
o embryonic
o fetal
o umbilical cord
o adult
Embryonic stem cells
o Pluripotento Ability to differentiate into most cell types
o Ex: Late Embryonic stem cells
Adult stem cells
o Multipotent
o usually just differentiates into cell types associated
with tissue where stems cells located
o Ex: adult stem cells in the brain
o -> nerve cells
o -> cells important for xmiss of nerve cell signals
o Plasticity- some types of adult stem cells may exhibit this
o If plastic, then could be considered pluripotent.
Where are stem cells produced?
o Embryonic stem cells
o in the inner cell mass of the blastocyst
o Adult stem cells
o in small numbers in some tissues in the body
(bone marrow, brain, skin etc.)
o
scientists still working to discover origin of adult
stem cells
How used in Medicine?
Current practical application of stem cell
therapy is somewhat limited
Adult blood-forming stem cells (found in
bone marrow) have been transplanted to
treat blood disorders for 40 years

Leukemia, lymphoma, other blood disorders
Potential Application of Research
Renewable source of organ/tissue
replacement


need for transplant organs >
# available donated organs.
may be used as “replacement cells”:
Alzheimer’s
stroke
diabetes,
arthritis, spinal cord injury, and heart disease
Potential Application of Research
Problems in differentiation ->

Potential partial cause of:
cancer
many birth defects

Stem cell research will likely lead to better
understanding of cell differentiation.
Development and testing of new drugs
Some Potential Problems in
Applications of Stem Cell Research
Immune Rejection
Controlling Cell Differentiation
Ethical Issues
Protective rights for embryos?
Morally acceptable to use stem cells obtained
from in vitro fertilization (IVF)?
Is stem cell therapy that involves cloning a
human cell (therapeutic cloning) morally
permissible?
How should federal funding be used to support
stem cell research?
Who will have access to stem cell therapy?
Some Misconceptions about Stem
Cell Research
Stem cells are currently being used to cure
many diseases.
Others?