20 - Stem Cells

Question 1

Tissue/organ regeneration is primarily driven by what three things?

Answer 1

1. Differentiation of stem cells - hair, blood, intestine
2. proliferation of existing cells - liver
3. Uncommonly by transdifferentiation

Question 2

What are the three goals of regenerative medicine?

Answer 2

1. Restore normal organ function by regenerating or replacing damaged cells with healthy ones
2. Production of limitless supplies of healthy cells from stem cells
3. Produce tissue or organs in the lab for transplant

Question 3

Define stem cells

Answer 3

Cells that can self-renew for long periods of time and remain unspecialiez.

Can differentiate into many cells types in the body.

Question 4

What are pluripotent stem cells?

Answer 4

Have the potential to become 200+ cell types and can make viable organisms,.

Embryonic stem cells (ESC) from blastocysts.

Induced pluripotent stem cells (iPSCs) reprogrammed somatic cells

Question 5

What are multipotent stem cells?

Answer 5

Cells that can differentiate into a restricted number of specialized cell types which commonly are related.

Sometimes called progenitor cells.

Question 6

What are unipotent stem cells?

Answer 6

Cells that have the ability to form only one cell type.

Often in niches of individal developed organs.

Question 7

What are some sources of stem cells?

Answer 7

Human embryonic stem . ells (hESCs)

fetal brain tissue, fetal retina

Umbilical cord blood

Amniotic fluid

Adult brain tissue

Bone Marrow

Skeletal muscle

Fat

Question 8

How is a stem cell line produced?

Answer 8

1. Embryo begins to divide
2. Blastocyst formed
3. 5-7 days embryonic stem cells are viable and capable of developing into anything
4. ICM (embryo) cells are removed and grown in petri dish
5. Different nutrients used depending on what it needs to being

Question 9

What is an alternative method for generating pluripotent stem cells? What is an example of this?

Answer 9

Nuclear transfer into a somatic cells to create a pluripotent stem cell.

This was done for dolly the sheep.

Question 10

What are induced pluripotent stem cells (iPSCs)? Why is this more ethical?

Answer 10

When skin cells are formed to over express stem cell genes, they are made into induced pluripotent stem cells.

Similar properties to embryonic stem cells without using the embryo.

Question 11

What are the strength of using pluripotent cells?

Answer 11

Generates the widest variety of tissue for scientific discovery and therapeutic use.

Question 12

What is the weakness of using pluripotent cells?

Answer 12

1. ethical concerns
2. immune rejection
3. tumors

Question 13

How do you prevent stem cells from growing tumors in patients?

Answer 13

You have to differentiate them before transplanting them.

Question 14

What are three types of fetal/adult stem cells (multipotent)? What does each make?

Answer 14

1. endothelial progenitor cells (EPCs): from peripheral blood that can micro-vascularize tissues such as heart
2. Hematopoietic stem cells (HSCs): bone marrow and cord blood/placenta, can micro-vascularize.
3. Mesenchymal stem cells (MSCs): stromal tissue; bone cartiladge, endothelial

Question 15

What are strengths of adult stem cells (multipotent)?

Answer 15

1. Tumors rarely observed
2. Autologous transplantation
3. Ethical concerns minimal (except fetal derived)

Question 16

What are weaknesses of adult stem cells (multipotent)?

Answer 16

1. More restricted differentiation capabilities

2. Limited proliferation potential

Question 17

What are the types of resident adult stem cells that are from “niches” of individual tissues?

Answer 17

Skin, small intestine, skeletal muscle, brain, and lung.

Question 18

What are the known “niches: of resident stem cells?

Answer 18

Basal layer of dermis, crypt cells, dorsal ganglia, and cell matrix.

Question 19

What are strengths of restricted potential resident stem cells in niches?

Answer 19

Highly restricted differentiation reduces change of tumor formation

Same other strengths of adult stem cells.

Question 20

What is a weakness of restricted potential resident stem cells in niches?

Answer 20

Difficulty isolating and expanding stem cells from niches.

Question 21

What is the function of skeletal myoblasts? What type of stem cells are they? What activates them?

Answer 21

Can regenerate whole muscle.

Adult stem cells that reside in “niche” of sarcolemma and basal lamina.

Activated by injury - can be used for skin grafting.

Question 22

What are the biggest problems with stem cell transplantation?

Answer 22

Appropriate migration/differentiation/integration.

Immune rejection

Risk of teratoma or tumor

Unwanted side effects.