stem cells may2012

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Stem Cells



Learning Outcomes

• Explain what is meant by the terms: – stem cell

– pleuripotency – totipotency

• Discuss the way society uses scientific

knowledge to make decisions about theuse of stem cells in medical therapies.



What Are Stem Cells?

• The „Master‟ cells of the body

• Undifferentiated (not specialised) cells

• The precursors of all the specialisedcells in an organism



Where do Stem Cells come from?

• After fertilisation a ZYGOTE is formed

• A series of rapid cell divisions (cleavage)

follows• Smaller cells are produced after each

division



5 Days after Conception

BLASTOCYST

Outer

layerforms theplacenta

Inner cell massgoes on to form

the tissues ofdevelopingembryo. Cellsreferred to as

PLURIPOTENT

EMBRYONICSTEM CELLS



Differentiated Cells

• As embryo develops cells become specifictypes of cell (DIFFERENTIATED)

• Some cells even in adults can turn into alimited number of cells e.g. neural stem cells& white blood stem cells.

• These cells are called MULTIPOTENT



Medical Uses of Stem Cells

• Adult stem cells have been used forover 30 years to treat….

• Leukaemia & Lymphoma



Potential use of Stem Cells

• Parkinson‟s Disease

• Brain Damage

• Cancer

• Spinal cord injury

• Muscle damage

• Heart damage

• Arthritis

• Osteoporosis

• Low blood supply

• Baldness

• Missing teeth

• Deafness

• Blindness andVision Impairment

• ALS (Lou Gehrig'sDisease)

A Universal Human Donor Cell



Where to get Embryonic StemCells

• Pluripotent cells isolated from „spare

embryos‟ from IVF treatment

• Embryos allowed to grow to formblastocysts

• Stem cells isolated, then cultured to

hopefully develop into tissues

• Rest of embryo discarded



Other Sources of Stem Cells

• Adult Stem Cells

– Somatic Stem Cells (multipotent)

– Induced pluripotent stem cells

• Fused Stem Cells

– Adult cell nucleus put into enucleated eggcell

• Hybrid Embryos

– Enucleated animal egg cell (e.g. bovine)with human body nucleus inserted



Ethical Concerns



Ethical Concerns

• Most people agree that there are noethical objections to using adult

multipotent stem cells.• Different people see the status of the

human embryo differently



Ethical Frameworks

Making decisions foryourself

I‟m ill, I want the treatment

It‟s my embryo

Maximising the amount ofgood in the world

More treatments = Healthier People

Rights & Duties

Human rights

Right to life

Religious teaching

Leading a virtuous life

Justice: If it‟s legal then its OK Wisdom: Scientific advances are

important

Moderation: multipotent cells OK,

pluripotent cells not OK



Religious Concerns

• Religious concerns are rooted in viewsabout „life‟. What is life…?

– the accidental result of the interaction ofchemical substances?

– the gift of a Creator God?

Your personal answer to this question may affecthow you feel about stem-cell research. But try toput yourself in other people‟s shoes…



Life…an accident?

• Some secular philosophers would argue thathuman life is precious because it is rare (ingalactic terms). Therefore to destroy life is

morally wrong.

• Others would argue that there is no difficulty inusing the cells of a zygote or blastocyst – as

many die naturally in any case.• Difficult choices: is it morally defensible to use

one (potential) life to help another?



If Life is an accident, you tell me…

• If life is an accident, does it matter whathappens to a few cells?

• Is there any difference between destroying a

potential human or, say, eating meat?• Is there a reason for considering human life to

be more precious than any other life?

• Is it morally right to use one life to saveanother?

• Is a potential human less valuable than adeveloped human?



Life…a gift? Consider the Bible…

• “You (God) created my inmost being; you knit me together in my mother‟s womb”

( Psalm 139)

• “The Lord God formed the man from the dust of

the ground and breathed into his nostrils the

breath of life, and the man became a living being” (Genesis 2:7)



Life…a gift? Consider the Qur‟an…

(Surah 23:12-14)

• Verily, We created man from a product of wet earth; (raw materials of life)

• then placed him as a drop of seed (sperm/egg?) in a

safe lodging (womb?)• then We fashioned the drop into a „clinging thing‟

(zygote?)

• then We fashioned the „clinging thing‟ into a „little

lump‟ (blastocyst?)• then we fashioned bones for the little lump (foetus?)

• then we clothed the bones with flesh (developedfoetus?)

• and then produced it as another creation. (baby)



Life…a gift?

• Some religious philosophers (theologians)argue that a gift from God comes with certain „conditions‟ – like a manufacturers instructions.

(e.g. “Warranty is void if cover is removed”)

• Those conditions may include:

- “The Lord gives and the Lord takes away”

- “Love your neighbour as you love yourself”

- “You shall not murder”



Life…a gift?

Some theologians draw a distinction between human and animal life.

So…for them…it may be acceptable to use

animal stem cells, but not human ones.

Such theologians would also draw the line atcombining human and animal cells formedical treatment.



Life…a gift?

Other theologians argue that we must balance scripture with reason…

e.g. God has given us the ability to reason out themechanics of life (biology). Knowing that manyeggs, zygotes and blastocysts do not survivenaturally, may be an indication that God is

unconcerned about stem cell research. e.g. God brings healing through the skills ofscientists and doctors (to whom he has given thegifts of reason).



Let there be life!

65% Oxygen

18% Carbon10% Hydrogen

3% Nitrogen

1.5% Calcium

1% Phosphorous0.2% Potassium

0.3% Sodium Chloride

1% Trace Elements

Trace elements:

Magnesium, Iron, Fluorine, Zinc,Silicon, Zirconium, Rubidium,Strontium, Bromine, Lead, Niobium,Copper, Aluminium, Cadmium, Boron,Barium, Arsenic, Vanadium, Tin,Mercury, Selenium, Manganese,Iodine, Gold, Nickel, Molybdenum,Titanium, Tellurium, Antimony,Lithium, Chromium, Cesium, Cobalt,Silver, Uranium, Beryllium, Radium.

We know that the human body is made upof:



65% Oxygen

18% Carbon

10% Hydrogen

3% Nitrogen1.5% Calcium

1% Phosphorous

0.2% Potassium

0.3% Sodium Chloride1% Trace Elements

Trace elements:

Magnesium, Iron, Fluorine, Zinc,Silicon, Zirconium, Rubidium,

Strontium, Bromine, Lead, Niobium,Copper, Aluminium, Cadmium, Boron,Barium, Arsenic, Vanadium, Tin,Mercury, Selenium, Manganese,Iodine, Gold, Nickel, Molybdenum,

Titanium, Tellurium, Antimony,Lithium, Chromium, Cesium, Cobalt,Silver, Uranium, Beryllium, Radium.

Challenge…from Religion…

GO on…MAKE A HUMAN BEING!

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