Where do Embryonic stem cells come from?
A fertilized egg
Where do Fetal Stem cells come from?
- Umbilical cord blood
- Placenta
- amniotic fluid
- aborted fetus
Where do adult stem cells come from?
- Bone marrow
- Blood (hematopoietic & mesenchymal)
- Fat
- Most tissues like Heart, Liver, Muscle, Brain..
What is differentiation?
The process by which a less specialized cell becomes more specialized
What are the different types of potency in stem cells, listed from most potent to least potent?
- Totipotent
- Pluripotent
- Multipotent
- Progenitor
Why are Embryonic stem cells only considered Pluripotent?
-They cannot differentiate into placenta cells
What are the criteria for a stem cell in general?
- No special function
- Self renewal
- Differentiation
- Clonality (gives rise to multiple tissues)
What does clonality mean?
A single cell can give rise to multiple tissues
From where in the developing embryo are embryonic stem cells taken?
The inner cell mass of the blastocyst
What is somatic cell nuclear transfer?
(SCNT) Take a nucleus from a somatic cell and put it in an empty egg. Not very efficient.
How can embryonic stem cells be induced from Pluripotent Stem Cells?
A viral transfection of genes coding for embryonic transcription factors
What is a teratoma?
A specific tumor formed after injection of pluripotent stem cells into an immuno-suppressed mouse
What are the advantages of embryonic stem cells?
- Can produce any cell type
- Easy to isolate, maintain, and identify
- Grow in large numbers
- grow fast
- Large source of blastocysts
What are the disadvantages of Embryonic Stem cells?
- Need to differentiate before application
- Form Teratomas
- Cannot be harvisted from the same individual who needs it (immuno-suppression)
- contamination
- Ethical, moral, and legal restrictions
How are embryonic stem cells currently used?
- only in research and drug testing
- no clinical applications
What are current uses of fetal stem cells?
- cord blood for hematopoietic and genetic disorders
- Leukemia/blood cancer
- diabetes
- Brain injury
What is a stem cell niche?
a cluster of adult stem cells that consists of stem cells in varying differentiation states
What are the advantages of Adult Stem cells?
- can be harvested from same individual
- no teratomas
- More specialized toward desired lineage
- No contaminants
- No major ethical concerns
What are the disadvantages of adult stem cells?
- Rare (1 in 10,000 cells)
- Not in every tissue
- Hard to isolate and maintain and identify
- Proliferate slow in vivo, even slower in vitro
- Self renewal is limited
What are the current uses of adult stem cells?
- Research
- Drug toxicity testing
- Several clinical applications, mostly burn healing and leukemia
