Prepared by the

AUSTRALIAN STEM CELL CENTRE

         

     

Introduction to Stem Cells

Introducing….stem cells!

What are stem cells?

• the body is made up of about 200 different kinds of specialised cells such as muscle cells, nerve cells, fat cells and skin cells

• all cells in the body come from stem cells• a stem cell is a cell that is not yet

specialised• the process of specialisation is called

differentiation• once the differentiation pathway of a stem

cell has been decided, it can no longer become another type of cell on its own

Stem cells can:• self-renew to make

more stem cells• differentiate into a

specialised cell type

Embryonic stem cells (pluripotent)

Stem cells that can become many types of cells in the body are called pluripotent

Tissue stem cells (multipotent)

Stem cells that can become only a few types of cells are

called multipotent

Why are stem cells special?

Tissue stem cells• often known as adult stem cells• also includes stem cells isolated from fetal

and cord blood• reside in most tissues of the body where

they are involved in repair and replacement

• generally very difficult to isolate• already used to treat patients

(haematological malignancies, diseases of the immune system)

Bone marrow Kidney Lung

8-cell blastocystfertilised egg

2-cellegg

Day 0 Day 1 Day 2 Day 3 Day 6

• Donated excess IVF embryos

Images from www.advancedfertility.com

Where do embryonic stem cells come from?

Inner cell mass

Embryonic stem cells

• derived from donated IVF embryos

• can be grown indefinitely in the laboratory in an unspecialised state

• retain ability to specialise into many different tissue types – know as pluripotent

• can restore function in animal models following transplantation

Human embryonic stem cells can become any cell in the body including these beating heart cells

human embryonic stem cells

What about cloning? Has that got anything to do with stem cell research?

Dolly the Sheep

Reproductive CloningSomatic Cell Nuclear Transfer – cloning to make stem cells (therapeutic cloning)

Snuppy the Puppy

Human cloning is banned in Australia and many countries

around the world.

Induced pluripotent stem cells

• derived from adult cells in 2007 - very recent discovery!

• can be grown indefinitely in culture in an undifferentiated state

• similar properties to embryonic stem cells as can differentiate into many different tissue types –pluripotent

• can create stem cells directly from a patient for research

Induced change in gene expression

pluripotent stem cells

Starting cells from donor tissue

iPS Cells

Using stem cells to conduct medical research and treat disease is acceptable?

• Don’t know

• No

• Yes

3%

5%

92*%

Biotechnology Australia – Community Attitudes to Biotechnology (2007)

* Compares to 80% in 2005 survey

But which type of stem cells?- pluripotent stem cells (embryonic, SCNT, iPS stem cells)- tissue stem cells (foetal, cord, adult)

Do you approve of the extraction of stem cells from human embryos for medical research?

• Don’t know

• No

• Yes

Roy Morgan Poll (2006)

5%

13%

82%

Areas of community concern– How come there are excess IVF embryos?– Why do the embryos have to be destroyed for

stem cell research? Isn’t this the same as taking a life?

– Wouldn’t it be better to donate the excess IVF embryos to other infertile couples?

– Could women be forced to sell eggs or embryos for research?

– Won’t doing therapeutic cloning lead to cloning humans?

– Why do we need to keep using embryos in research when we have new iPS cells?Australia has clear rules that allow embryos to be used in research under strict conditions.

All research whether it involved embryonic, adult, cord, fetal, iPS stem cells must have special ethics approval before research can start.

What makes stem cells so valuable?

Modified from Keller & Snodgrass, Nat Med 1999

Cell Therapy

Research

New Drugs

Pluripotent stem cells

Tissue stem cells

No one stem cell type fits all applications.

Research must continue using all types of stem cells.

Direct marketing to patients promising instant results for incurable diseases

Stem Cell TourismA growing concern to the stem cell community

www.stemcellcentre.edu.auwww.stemcellchannel.com.au