Lecture 14 - Ethics & Stem Cells

Question 1

Is it acceptable to use stem cells to conduct medical research and treat disease?

Answer 1

It depends on which type of stem cells we are talking about

Acceptable:
• Adult SCs
• iPSCs

Unacceptable:
• ESCs
• SCNT

Question 2

Where do embryonic stem cells come from?

Answer 2

Excess embryos from IVF that have been donated to research

From inner cell mass of blastocyst

Around day 6 after fertilisation

The harvesting of cells in this way destroys the embryo

Question 3

What are the concerns with using human ESCs?

Answer 3

• An embryo is a life ?
• Why do IVF embryos have to be killed to get stem cells?
• Are IVF clinics purposely making ‘excess’ IVF embryos?
• Are IVF couples forced to donate their embryos?
→ fear poor treatment if they don’t agree

Question 4

What is SCNT?

Answer 4

Somatic cell nuclear transfer

Nucleus from patient’s cells is transferred to enucleated oocytes

Oocyte then develops into an embryo, and inner cell mass cells are harvested

We now have ESCs that are genetically identical to the patient

Question 5

What are the concerns with SCNT?

Answer 5

• SCNT generation destroys a life (an embryo)
• SCNT could clone humans?
• Could women be exploited, i.e. forced / able to sell eggs?
• SCNT will be used to create chimaeras if animal eggs are used?

Question 6

What are iPS?

Answer 6

Induced pluripotent stem cells

Differentiated somatic cells from an individual are harvested from skin and treated with four transcription factors

Somatic cells are ‘re-set’ and become pluripotent

Question 7

What are the ethical issues of iPS?

Answer 7

• Cloning is still possible (Xiao Xiao the mouse)
• ? creating a life for destruction
• Possibly oncogenic
• Cost (prohibitive, only for the wealthy)
• Can be done secretively, as opposed to ESCs

Question 8

How was Dolly cloned?

Answer 8

SCNT

Question 9

Can iPS be used for cloning?

Answer 9

Yes
Xiao xiao the mouse was cloned using iPS

Approach:
1. Two cell embryo fused to generate a tetraploid blastocyst

2. iPS cells are injected into the tetraploid blastocyst
3. iPS cells steer development
4. Developing embryo is implanted into a surrogate mother

Question 10

Describe the regulation of use of stem cells

Answer 10

Use of stem cells is highly regulated

Legislation:
• Research Involving Use of Human Embryos Act 2002
• Prohibition of Human Cloning Act 2002

Must have:
• Ethics approval
• NHMRC licence

• SCNT for stem cells is allowed since a 2006 amendment
• However, transfer of the generated embryo into a woman or animal is prohibited

Different countries have differed restrictions:
• Permissive approach
• Intermediate approach
• Restrictive approach

Question 11

How could stem cells be used for therapy?

Answer 11

• Blood generation
• Growth of new organs
• HSC treatment of leukaemia

Question 12

List some hazards of unproven stem cell treatments

Answer 12

• Lack of proven benefits
• Financial exploitation
• Diversion from existing proven therapies
• Disqualification from future clinical trials

• Risk of physical harm

• Unexpected growths
• Tumours
• Death

Question 13

What unproven SC trials are offered in Australia?

Answer 13

Increasing number of autologous “stem cell” / SVF treatment

Usually liposuction derived, but also peripheral blood

V. expensive ($9+ K per treatment)

Offered for:
 • Autism
 • Osteoarthritis
 • Retinal neuropathy
 • MS
 • MND

Question 14

Describe Australians’ opinions of the following:
• Acceptability of use of SCs
• Impact of SCs
• Risk of using SCs

Answer 14

Australians think that SCs are very impactful and acceptable to use

They think that the associated risks are low

Question 15

What is the difference between embryos and foetal tissue?

Answer 15

Embryos: not yet implanted

Foetal tissue: implanted in endometrium