Flashcards in Stem Cells Deck (26):
What are some functions of stem cells?
Develop into an organism/tissue, maintain an organism/tissue (ie blood, skin—thus
involved in homeostasis), repair tissue (regeneration). They’re a constant pool for new
cells as long as the individual lives.
A fertilized egg has what type of stem cells?
Embryonic stem cells
What types of stem cells are contained in the placenta and umbilical cord blood
Fetal stem cells
Bone marrow and tissues (ie heart, liver, blood, fat, etc) have what type of stem cells?
Adult stem cells/progenitor cells
A stem cell is a single cell that has no special function, but has capacities for what?
Self-renewal (can give rise to a cell of the same type), differentiation, and clonality (a
single cell gives rise to multiple tissues).
What is the order of stem cells in terms of their capacity to differentiate
embryonic > fetal > adult
Where are true embryonic stem cells found naturally?
in the blastocyst; requires destruction of the potential embryo; usually obtained from
in vitro fertilization
How can we get ES cells through somatic cell nuclear transfer (SCNT)?
Use a somatic cell nucleus, put it in an egg cell. There’s no sperm necessary and
requires the destruction of the potential embryo
What types of cloning therapy can SCNT be used for?
Reproductive cloning - The new individual is a “clone” of the donor individual of the somatic cell
Therapeutic cloning - ES cells are a pool of “personalized” cells for donor individual,
Research cloning - ES cells allow us to study the exact disease/condition of the donor individual; so far, only works in animals, not in humans
What are fundamental ethical concerns regarding ES cells?
Requires destruction of an embryo
How do we achieve induced pluripotent stem cells (iPS)? Why is this method more ethically sound?
Viral transfection of genes coding for embryonic transcription factors in a somatic cell
There’s no potential embryo, thus no destruction
What are specific ES cell (pluripotent) criteria?
Must grow at least 10-12 months in an undifferentiated state, must express certain
stem cell markers on surface, must express certain transcription factors, need intact DNA, must be able to differentiate spontaneously and directionally,must be able to regenerate all cells of all 3 germ layer lineages, must be able to form a specific tumor (teratoma) after injection into immune-suppressed mice, must yield viable offspring when injected into empty blastocyst and implanted into mouse
What are the advantages of ES cells?
Can produce any cell type, easy to isolate/maintain/identify, grow in large numbers,
grow fast, large source of blastocysts from in vitro fertilization clinics
What are some disadvantages of ES cells?
Form teratomas easily, major ethical concerns, need to differentiate before application
True or false: There is no clear border between fetal stem cells and adult stem cells.
Are fetal stem cells pluripotent?
No, they are multipotent. They give rise to numerous (but not all) cell types. They do
not form teratomas.
Where can we find adult stem cells? Name some characteristics.
A: They’re found in almost all tissues, but most prominent: bone marrow, neural, cardiac,
epithelial, skin, adipose-derived. They are multi-potent. They can differentiate into other
cell types of different tissues
What stem cells function in bone marrow transplantation
Hematopoietic stem cells
Where are mesenchymal stem cells found? Also called what?
Bone marrow, bone, muscle, fat, skin, cartilage. They’re also called stromal stem cells
What stem cell is most used for tissue engineering
Can adult stem cells for teratomas
What are some advantages of adult stem cells?
Do not form teratomas, are already more specialized towards the desired lineage, no major ethical concerns
What are some disadvantages of adult stem cells?
Are rare and in small number, not in every tissue, proliferate slow, self renewal is limited
What are the current uses of embryonic stem cells?
Mostly research and drug testing - studying
Only clinical trial is for retinal pigment epithelial cells to treat blindness from Stargardt's disease
What are current uses for fetal stem cells?
Cord blood is being used to treat hematopoietic and genetic disorders like leukemia, diabetes, brain injury