2.6.11 The Use Of Stem Cells

Question 1

Use of Embryonic Stem Cells

Answer 1

Due to their ability to differentiate into multiple cell types, stem cells have huge potential in therapeutic treatment of disease
For many countries, such as the USA and some countries within the EU, the use of embryonic stem cells is banned, even for research
In other countries, such as the UK, the use of embryonic stem cells is allowed for research but is very tightly regulated
Embryonic stem cells can be one of two potencies:
- totipotent if cells are taken in the first 3-4 days after fertilisation
- pluripotent if taken on day 5
The embryos used for research are often the waste (fertilised) embryos from in vitro fertilisation (IVF) treatment
- this means these embryos have the potential to develop into human beings
- this is why many people have ethical objections to using them in medicine or research

Question 2

Use of Multipotent Adult Stem Cells

Answer 2

Adult stem cells can divide (by mitosis) an unlimited number of times but they are only able to produce a limited range of cell types
A small number of adult stem cells are found in certain tissues within body, such as:
- bone marrow - used to produce different types of blood cell
- brain - used to produce different types of neural and glial cells
These small number of stem cells remain to produce new cells for the essential processes of growth, cell replacement and tissue repair
Research is being carried out on stem cell therapy, which is the introduction of adult stem cells into damaged tissue to treat diseases (e.g. leukaemia) and injuries (e.g. skin burns)
The use of adult stem cells is less controversial than embryonic stem cells because the donor is able to give consent
However, if multipotent stem cells are being donated from one person to another, they need to be a close match in terms of blood type and other body antigens
- there is a chance that the cells used are rejected by the patient’s immune system
Ideally, the patient’s own adult stem cells are used to treat them, as there is a much lower chance of rejection

Question 3

Diseases that can be treated using Stem Cells

Answer 3

Alzheimer’s Disease - most common type of dementia, which leads to memory loss and the loss of other cognitive abilities - stem cells can be grown into nerve cells. This has the potential to repair this neurological condition. This is difficult as damage to the brain in dementia patients is widespread rather than localised to a specific area
Parkinson’s Disease - causes the shaking, stiffness and slowness of movement in people with it, due to the death of the death of domaine producing brain cells - stem cells could be used to replace these dopamine producing cells
Age-Related Macular Degeneration- causes damage to the macula of the retina, which is a common condition that causes loss of vision in over 50s - stem cells can be used to grow replacement retinal cells
Spinal Injuries - damage to spinal tissue can lead to loss of movement (paralysis) and/or loss of sensitivity in different parts of the body - stem cells can be introduced to the site of then spinal injury to try repair the damage
Blood Diseases - there are many different blood diseases that can cause a wide range of problems e.g. sickle cell disease - bone marrow stem cells can be sued to treat a number of these diseases
Type 1 Diabetes - little or no production of insulin by the pancreas, resulting in high blood sugar levels - stem cells could be differentiated into insulin producing pancreas cells and transplanted into the patient
Heart Attack - can cause damage to heart tissue - stem cells could be used to repair this damage

Question 4

Evaluation of the Use of Stem Cells

Answer 4

Benefits of Using Stem Cells
- great potential to treat a widespread variety of diseases from diabetes to paralysis
- organs developed from a patient’s own stem cells reduces the risk of organ rejection and the the need to wait for an organ donation
- adult stem cells are already used successfully inn a variety of treatments, acting as proof of benefits
Risks/Issues of Using Stem Cells
- stem cells cultured in labs could become infected with a virus which could be transmitted to the patient
- there is a risk of cultured adult stem cells accumulating mutations that can lead to them developing cancer cells
- low number of stem cell donors
Social issues
- it is possible for embryonic stem cells to be collected before birth (from amniotic fluid) or after birth (umbilical cord) and stored by a clinic but this can be expensive and isn’t an option for everyone
- a lack of peer-review clinical evidence of the success of stem cell treatments
- educating the public sufficiently about what stem cells can and cannot be used for
Ethical Issues
- stem cells may be sourced from unused embryos produced in IVF treatment but is it right to use them? Who gives permission?
- is it right to create embryos through therapeutic cloning and then destroy them? Who owns the embryos?
- should an embryo be treated as a person with human or rights or as a commodity?