Stem Cells

Question 1

What are some functions of stem cells?

Answer 1

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.

Question 2

A fertilized egg has what type of stem cells?

Answer 2

Embryonic stem cells

Question 3

What types of stem cells are contained in the placenta and umbilical cord blood

Answer 3

Fetal stem cells

Question 4

Bone marrow and tissues (ie heart, liver, blood, fat, etc) have what type of stem cells?

Answer 4

Adult stem cells/progenitor cells

Question 5

A stem cell is a single cell that has no special function, but has capacities for what?

Answer 5

Self-renewal (can give rise to a cell of the same type), differentiation, and clonality (a
single cell gives rise to multiple tissues).

Question 6

What is the order of stem cells in terms of their capacity to differentiate

Answer 6

embryonic > fetal > adult

Question 7

Where are true embryonic stem cells found naturally?

Answer 7

in the blastocyst; requires destruction of the potential embryo; usually obtained from
in vitro fertilization

Question 8

How can we get ES cells through somatic cell nuclear transfer (SCNT)?

Answer 8

Use a somatic cell nucleus, put it in an egg cell. There’s no sperm necessary and
requires the destruction of the potential embryo

Question 9

What types of cloning therapy can SCNT be used for?

Answer 9

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

Question 10

What are fundamental ethical concerns regarding ES cells?

Answer 10

Requires destruction of an embryo

Question 11

How do we achieve induced pluripotent stem cells (iPS)? Why is this method more ethically sound?

Answer 11

Viral transfection of genes coding for embryonic transcription factors in a somatic cell

There’s no potential embryo, thus no destruction

Question 12

What are specific ES cell (pluripotent) criteria?

Answer 12

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

Question 13

What are the advantages of ES cells?

Answer 13

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

Question 14

What are some disadvantages of ES cells?

Answer 14

Form teratomas easily, major ethical concerns, need to differentiate before application

Question 15

True or false: There is no clear border between fetal stem cells and adult stem cells.

Answer 15

True

Question 16

Are fetal stem cells pluripotent?

Answer 16

No, they are multipotent. They give rise to numerous (but not all) cell types. They do
not form teratomas.

Question 17

Where can we find adult stem cells? Name some characteristics.

Answer 17

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

Question 18

What stem cells function in bone marrow transplantation

Answer 18

Hematopoietic stem cells

Question 19

Where are mesenchymal stem cells found? Also called what?

Answer 19

Bone marrow, bone, muscle, fat, skin, cartilage. They’re also called stromal stem cells

Question 20

What stem cell is most used for tissue engineering

Answer 20

Mesencymal

Question 21

Can adult stem cells for teratomas

Answer 21

No

Question 22

What are some advantages of adult stem cells?

Answer 22

Do not form teratomas, are already more specialized towards the desired lineage, no major ethical concerns

Question 23

What are some disadvantages of adult stem cells?

Answer 23

Are rare and in small number, not in every tissue, proliferate slow, self renewal is limited

Question 24

What are the current uses of embryonic stem cells?

Answer 24

Mostly research and drug testing - studying

Only clinical trial is for retinal pigment epithelial cells to treat blindness from Stargardt’s disease

Question 25

What are current uses for fetal stem cells?

Answer 25

Cord blood is being used to treat hematopoietic and genetic disorders like leukemia, diabetes, brain injury

Question 26

What are the current uses for adult stem cells?

Answer 26

Extensive research application, drug and toxicology testing, several clinical applications; they are currently the best candidates for tissue regeneration