Stem cells and regenerative medicine

Question 1

what are the characteristics of stem cells

Answer 1

1. Are primitive or undiffertaited
2. Can divide indefinitely
3. Are self-renewing
4. Give rise to progeny that differentiate into specialised cells

Question 2

what is the mulipotential capacity of

• totipotent
• pluripotent
• multipotent
• oligopotent
• unipotent

Answer 2

• totipotent - can differentiate into anything including the placenta
• Pluripotent – can differentiate into cells derived from any of the three germ layers – they can’t develop into the placenta – naturally occur within embryos
• Multipotent – can give rise to several specialised cells or tissues of an organism – often tissue specific
• Oligopotent – can generate a few cells types within a particular tissue
• Unipotent – can produce only one cell type but still capable of self-renewal

Question 3

what are stem cells maintained by

Answer 3

• Stem cells are through to be maintained by the environment produced by surrounding differentiated cells

Question 4

how does the niche environment regulate stem cells

Answer 4

• Secrete specific factors into the surrounding matrix
• Communicate with the stem cells via gap junctions
• Changes within the niche may induce a stem cell to die, divide or differentiate

Question 5

what are the two methods of differentiate in stem cells

Answer 5

• symmetric cell division

- asymmetric cell division

Question 6

what is symmetric cell division

Answer 6

• Stem cell + Stem Cell

- Differentiated cell + Differentiated cell

Question 7

what is asymmetric cell division

Answer 7

Stem Cell + Differentiated Cell

Question 8

what is an embryonic stem cell derived from

Answer 8

• ES cells lines are derived from individual ES cells

- Common source – IVF – embryos in excess of clinical need

Question 9

what are the ways that embryonic stem cells can be identified from other cells

Answer 9

• stem cells have immortality
• clonaility - maintain a normal karyotype and have expression of telomerase
• undifferentiated - there are only marks that are found in undifferated stem cells Oct14 Nanog
• wide developmental potential - able to differentiated into a wide range of cell types in Vitor and in vivo

Question 10

what are the challenges of using embryonic stem cells for transplantation therapies

Answer 10

Purity/production problems
Cancer problems
Immunology problems
Ethics problems

Question 11

what are the potential solutions to immune rejection using embryonic stem cells

Answer 11

• large banks of ES cells
• manipulation of histocompatibility genes in ES cells
• replacement of hematopoietic tissue of patient with ES-derived cells prior to graft
• immunosuppressive drugs or antibodies
• therapeutic cloning

Question 12

how does therapeutic cloning work

Answer 12

• Take somatic cell
• Pop out nucleus from the somatic cell
• Unfertilised egg remove the nucleus
• Combine nucleus and anulcear unfertilised egg
• Then diploid oocyste
• Shock
• Development
• Blastocyst
• Then this can create embryo stem cell line

Question 13

what are the benefits of therapeutic cloning

Answer 13

1. Ideal tissue for regenerative medicine because genetically identical to patient
   - circumvents problem of tissue rejection
   - model a patient’s specific disease

Question 14

what are the challenges and controversies of therapeutic cloning

Answer 14

1. Percentage of successful clones is low – long time-frame to generate
2. Creating potential embryo (not fertilized) for research/treatment
3. Practical - source of oocytes? Should women donate for such research/treatments?
4. Slippery slope to reproductive cloning

Question 15

describe how reproductive cloning works

Answer 15

• Same process
• Implant back into the surrogate mum
• Get cloned
• For example dolly the sheep

Question 16

what is the ethical debate of embryos

Answer 16

• Are humans playing god
• Will embryo arms be around in the future
• Will healthcare costs skyrocket
• Is it morally right
• Are embryos alive

Question 17

what is the regulation of experiments on embryos

Answer 17

• can only be legally used up to 14 days of development in some countries, in others this is only a guideline

Question 18

what are adult stem cells

Answer 18

• Rare, undifferentiated cells found among differentiated cells in a tissue or organ
• Capable of differentiating to produce the major specialised cell types of the tissue

Question 19

what is the primary role of adult stem cells

Answer 19

• Primary role: to maintain and repair the tissue in which they are found

Question 20

what type of stem cells are adult stem cells

Answer 20

• Multipotent, not pluripotent

Question 21

what are the advantages for using adult stem cells

Answer 21

• No legal or ethical concerns
• Using a patient’s own cells circumvents the problem of immunological rejection
• Injection of normal somatic stem cells has not lead to tumour formation
- By learning to manipulate endogenous adult stem cells in the body we may learn how to repair ourselves avoiding the problems of cell transplantation

Question 22

what are the examples of bone marrow transplants

Answer 22

• Bone marrow transplants

- Skin grafts for burn victims

Question 23

what is an example of stem cell success

Answer 23

• Repair and replace strategy
• Remove stem cells from a patients bone marrow
• Transfer a correct copy of the defective ADA gene
• Replace cells
• The therapy was tested on 18 children, the first of them 15 years ago, all are still alive

Question 24

what is an induced pluripotent stem cell

Answer 24

Add certain genes to the cell and this sets the cell back to the inducted pluripotent stem cells this then behaves like an embryonic stem cell

Question 25

what are the advantages of induced pluripotent stem cells

Answer 25

• No need from embryos

- Circumvents immunological rejection

Question 26

what are the challenges of induced pluripotent stem cells

Answer 26

Reduce risk of cancer
Remove the requirement for viral integration
Demonstrate long-term stability of re-programmed cells
Improvement of technical efficiency

Question 27

what are the potent of stem cells in the laboratory to study disease

Answer 27

• Research tool
• Diagnostic tool
• Therapeutic assessmenet