Stem Cells and Differentiation

Question 1

What are stem cells?

Answer 1

Are unspecialised cells that can self-renew indefinately and differentiate into specialised cells.

Question 2

What is stem cell potency?

Answer 2

A cell’s ability to differentiate into other cell types

Question 3

What are totipotent stem cells?

Answer 3

Can give rise to embryonic membrane and any cell type in the adult body (eg.s zygotes and morulas)
(Found in early cells of fertilised eggs)

Question 4

What are pluripotent stem cells?

Answer 4

Can give rise to any cell type of the adult body (eg.s embryonic stem cells, induced pluripotent stem cells).
(Found in inner mass cells of the blastocyst)

Question 5

What are multipotent stem cells?

Answer 5

Can give rise to tissue specific cell types of adult body (eg. haematopoetic stem cells)

Question 6

What are unipotent stem cells?

Answer 6

Can give rise to one specific type of adult body tissue cells.
(eg. epidermal stem cells can only become keratinocytes)

Question 7

How do stem cells differentiate?

Answer 7

• They undergo asymmetric division = produces 2 dissimilar cells.
• One daughter cell is identical and maintains the stem cell line.
• 2nd daughter cell has different genetic instructions, reduced proliferitive capacity, this cell will eventually become a progenitor cell, it is committed to producing one/ a few terminally differentiated cells.

Question 8

What are some examples of adult tissue stem cells and what they create?

Answer 8

• Haematopoetic stem cells; give rise to blood cells
• Neural stem cells; give rise to cells of the nervous system
• Mesenchymal stem cells; give rise to skeletal tissue, bone ,cartilage cells. (adipocyte, chondrocyte, osteocyte)
• Intestinal stem cells; give rise to cells of the intestine

Question 9

What are induced pluripotent stem cells?

Answer 9

Are cells that are reprogrammed back to pluripotency.

Question 10

Why is human embryonic stem cell use regulated?

Answer 10

Due to ethical considerations.
They must be obtained in embryos not ‘high quality enough’ for IVF.
This ethical dilemma is why iSPC’s are revoloutinising stem cell use.

Question 11

Why are adult stem cells tougher to use for research?

Answer 11

• They are hard to isolate
• They are few in no.
• They are hard to keep alive

Question 12

What are the characteristics of cancer stem cells?

Answer 12

• Exhibit characteristics of both stem and cancer cells
• Defined by their ability to generate more stem cells and to produce cells that differentiate.
• They also have the ability to seed tumours when transplanted into an animal host.

Question 13

Why are cancer stem cells important?

Answer 13

Knowledge of these may revoloutinise treatment as current treatments target tumours not cancer stem cells.

Question 14

What are the potential uses for stem cells clinically?

Answer 14

• Regenerative medicine (repair or replace damaged or diseased human cells or tissue to restore normal function)
• Tissue repair
• Drug screening
• Vehicles for gene therapy

Question 15

What are some of the successes in regenerative medicine?

Answer 15

• Bone marrow transplant to treat leukemia.

- Holocar to restore sight where there isn’t deep corneal stroma damage.

Question 16

What is the difference between autologous and allogenic treatment?

Answer 16

• Autologous; from recipient themselves (stem cells)

- Allogenic; from donor with same tissue type

Question 17

What is the haematopoetic stem cell pathway?

Answer 17

Haematopoetic stem cells will differentiate, creating more stem cells but also myeloid and lymphoid progenitor cells. Lymphoid progenitors will further differentiate to become lymphopcytes of NK cells.
Myeloid cells will further differentiate to become other white blood cells, red blood cells and platelets.

Question 18

How do red blood cells come about after myeloid progenitor cells?

Answer 18

Become proerythroblasts then become reticulocytes and then become red blood cells (erythrocytes).

Question 19

Where is EPO produced?

Answer 19

In the kidneys