A presentation on stem cells for the IB-1 students

1. Stem cells
http://www.extremetech.com/wp-
content/uploads/2014/07/stem-cells.jpg
Miltiadis-Spyridon Kitsos
Platon IB Diploma

2. Key facts: Fertilization and first embryo stages
http://www.nature.com/nature/journal/v487/n7405/images/487043a-f1.2.jpg
https://youtu.be/jsFn-_SC2Q8
In all animals reproducing sexually, life starts with the
formation of the zygote which will then undergo a
series of divisions and produce consecutive stages of
increasing numbers of cells (two-cell, four-cell, eight
cell etc.)
These cells have the ability to divide again and again
(increased division potential)

3. Key facts: Cell differentiation
The initial cells will eventually turn into
approximately 200 different cell types.
This process where the first embryo cells
change to more specialized cells, with
specific morphology and function
Is called cell differentiation
http://4.bp.blogspot.com/-
bw8IYEIqBWw/U0__6I0QymI/AAAAAAAAABY/7RYln5kyQmc/s1600/cell-types.bmp
Genes and cell differentiation
O
N
O
N
O
N
O
F
F
O
F
F
O
N
O
F
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O
F
F
All embryonic cells poses the same genes
which are all activated.
Cell differentiation is based on the
deactivation of gene sets.
The deactivation of certain genesm as well
as the activation of others, lead to the
development of different cell types.
Embryonic cell genes
http://res.cloudinary.com/dk-find-
out/image/upload/q_80,w_1440/AW_Nerve_impulse2_tcnrmm.j
pg
http://etc.usf.edu/clipart/69300/69336
/69336_cell_sections_mth.gif

4. Stem cells
 Thus the specialized tissues found in multicellular organisms are a result of cell differentiation
 Differentiation involves the expression of certain genes and not others of the genome.
 Differentiate cells will gradually loose their ability to switch to other cell types as well as their
ability to divide.
http://outreach.mcb.harvard.edu/animations/preloader
StemCells.swf
https://youtu.be/YtvL-LQlPrU
Two animations..

5. Stem cells Different cell types
As all branches of a tree develop from a main
stem, all cell types in human body arise from
embryonic stem cells which have the ability to
divide and differentiate
``
``
` Stem cell
Cell
differentiation
http://learn.genetics.utah.edu/content/stemcells/scintro/

6. Stem cells
Categories of
stem cells
Cell potency
(ability to
differentiate)
Totipotent Differentiate into
any type of cell
Pluripotent Differentiate into
many types of cells
Multipotent Can differentiate
into few types of
cells with functional
and morphological
similarities
Unipotent Have the capacity
to differentiate into
only one cell type
https://upload.wikimedia.org/wikipedia/commons/3/3c/Stem_cells_diagram.png
Hetmatopoiesis: A good example of shifting from
multipotency to unipotency
https://upload.wikimedia.org/wikipedia/commons/thumb/6/69/Hematopoiesis_%28human%29_diagram.png/1280px-
Hematopoiesis_%28human%29_diagram.png

7. Therapeutic use of stem cells
Stargardt’s macular degeneration is a rare genetic disease related with progressive vision loss.
It is the result of a mutation in the ABCA4 gene which in turn causes a malfunction in a membrane
protein related with active transport in retina cells.
It induces a progressive degeneration of the macula (a central area of the retina) which is related with
sharp central vision. Patients also suffer with difficulties in navigating in low light.
Symptoms appear at late childhood
Case study 1: Stargardt’s macular degeneration
http://ghr.nlm.nih.gov/condition/stargardt-macular-degeneration
https://www.youtube.com/watch?v=8QEYKPcD_qk
http://www.blindness.org/macular-degeneration
Learn more at:
http://www.blindness.org/macular-degeneration
Normal vision Stargardt’s

8. Therapeutic use of stem cells
Case study 1: using stem cells to treat Stargardt’s macular degeneration
Embryonic stem cells are cultivated in the lab.
They are treated with special chemical agents to
differentiate into retinal pigment epithelial cells.
Patches of cells are injected in the
damaged area of the eye.
Marked improvement in
eyesight has been reported
Read more
http://www.independent.co.uk/news/science/stem-cells-
the-first-human-trial-1824099.html
http://www.theguardian.com/science/2014/oct/15/stem-
cell-success-in-treating-macular-degeneration
http://www.the-
scientist.com/?articles.view/articleNo/42863/title/Eye-
Stem-Cell-Therapy-Moves-Ahead/
http://1.bp.blogspot.com/-GVzB16T5Jic/Tx7NeJJPavI/AAAAAAAAHfY/-
7hxelmGM2M/s1600/screen-capture-4.png

9. Therapeutic use of stem cells
Case study 2: leukemia
Leukemia is a malignancy of blood cells. It is related with an apparent large number of
changes (mutations) in the genome. Production of cancerous precursor blood cells in the
bone marrow leads to the development of abnormal white blood cells which grow in vast
numbers.
Soon the human body is unable to fight infection, control bleeding or even transport oxygen.
Leukaemia is the 12th most common cancer in Europe, with around 82,300 new cases
diagnosed in 2012 (2% of the total)
http://www.medicinenet.com/leukemia/page2.htm#what_is_leukemia_what_are_the_di
fferent_types_of_leukemia
Acute lymphoblastic leukemia Acute myelogenous leukemia Chronic lymphoblastic leukemia Chronic myelogenous leukemia
Found in lymphoid cells.
Grows quickly,
Common in children.
Found in myeloid cells.
Grows quickly,
Common in adults and
children.
Found in lymphoid cells.
Grows slowly,
Common in adults 55+.
Found in myeloid cells.
Grows slowly,
Common in adults.
https://blooddiseasedestination.files.wordpress.com/2014/11/leukemia1-
28129.jpg?w=840
http://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-
cancer-type/leukaemia/incidence#heading-Four

10. Therapeutic use of stem cells
Case study 1: using stem cells to treat Leukemia
Large needle is inserted in the bone
marrow of a large bone, fluid is
extracted and hematopoietic stem cells
are isolated
Stem cells are placed in cultures with
appropriate growth media
Chemotherapy is administered to kill all
bone marrow cancerous cells
Grown stem cells are introduced back to
the patients bone marrow. They start
multiplying and producing new white
and red blood cells.
Read more:
http://www.leukaemia.org.au/treatmen
ts/stem-cell-transplants/stem-cell-
transplants

11. Therapeutic use of stem cells
Media
https://youtu.be/2-3J6JGN-_Y
The heart makersStem cells: wonderful documentary
https://youtu.be/pd3TFB0wOI0
Stem Cell Treatment for Leukemia at UCH
https://youtu.be/FWruLa3Qsc4
http://outreach.mcb.harvard.edu/animations/thera7c.swf http://media.hhmi.org/biointeractive/click/Stem_Cell_
Therapies/01.html
http://www.sumanasinc.com/scienceinfocus/sif_ste
mcells.html

12. Sources of stem cells: ESC vs ASC vs iPSC
Embryonic
stem
cells
Adult
stem
cells
Induced
pluripotent stem
cells
Pluripotent- Almost unlimited growth
potential-may differentiate into any kind of
cell
Oligopotent – Unipotent- limited cell
potency
Less growth potential than
embryonic stem cells
Higher risk of tumor creation Less risk of tumor creation Less risk of tumor formation
Risk of being genetically different from the
recipient's cells – higher risk of rejection
Compatible with recipient’s cells –
low risk of rejection.
Compatible with recipient’s
cells – low risk of rejection.
Unlimited numbers of cells due to high cell
potency
Limited numbers may be obtained Rather Limited numbers may
be obtained
Very low probability of mutation-induced
damage in the DNA
Higher probability of mutation-
induced damage in the DNA – risk of
diseases
Higher probability of
mutation-induced damage in
the DNA – risk of diseases
New scientist (The collection): Medical frontiers, 2(2):
p. 73
New scientist (The collection): Medical frontiers, 2(2):
p. 73
New scientist (The collection): Medical
frontiers, 2(2): p. 73

13. Sources of stem cells
Embryonic
stem
cells
Adult
stem
cells
Induced
pluripotent cells
Ethical issues around the use of IVF
embryos for harvesting stem cells
No serious ethical issues related
with their use. Adult consent is
required for harvesting the adult
stem cells.
No serious ethical issues
related with their use.
New scientist (The collection): Medical frontiers, 2(2):
p. 73
New scientist (The collection): Medical frontiers, 2(2):
p. 73
New scientist (The collection): Medical
frontiers, 2(2): p. 73
Allott, Andrew, and David Mindorff. Biology: Course Companion. Oxford: OUP, 2014.
15. Print.

14. Ethics of stem cell use: a controversy
The Ethical Questions of Stem Cell Research
https://youtu.be/f5d0ieWfKlI
Fr. Mike McGovern on the Catholic Church's
Teaching on Stem Cell Research
https://youtu.be/SZ6VSZEiiG0
Obama : Stem Cells
https://youtu.be/NZdtzNmr4gw
Countries in brown have a permissive or flexible policy on
human embryonic stem cell research. With the exception
of the U.S. have banned by law human reproductive
cloning.
George W. Bush: On Stem Cell Research
https://youtu.be/EAiZp5jT04I
https://youtu.be/EAiZp5jT04I
Vatican finances adult stem cell
reasearch led by US university
http://www.mbbnet.umn.edu/scmap.html

15. • Stem cell research may pave the way for future discoveries and beneficial technologies
that would not have occurred if their use had been banned.
vs
• Involves the creation and destruction of human embryos (at what point do we afford the
right to life?)
• Stem cells can be taken from embryos that have stopped developing and would have died
anyway (e.g. abortions)
Vs
• More embryos are generally produced than are needed, so excess embryos are killed.
• May be used to cure serious diseases or disabilities with cell therapy (replacing bad cells
with good ones)
vs
• Embryonic stem cells are capable of continued division and may develop into cancerous
cells and cause tumors
Arguments for and against Therapeutic Cloning
Slide from Chris Paine’s
http://www.slideshare.net/diverzippy/biok-notes-11-introduction-to-
cells?ref=http://bioknowledgy.weebly.com/11-introduction-to-cells.html

16. • Transplants are less likely to be rejected as they are cells which are genetically
identical to the parent. Transplants do not require the death of another human.
vs
• With additional cost and effort, alternative technologies may fulfill similar roles
(e.g. nuclear reprogramming of differentiated cell lines)
• Cells are taken at a stage when the embryo has no nervous system and can
arguably feel no pain
vs
• Religious or moral objections due to the ‘playing God’ argument.
• The embryo which is created could potentially be used in IVF and develop into a
human fetus, so are we creating human life to destroy it?
• Although cloning humans reproductively is illegal, this has not been ratified by all
nations. Potential for a race to clone the first human.
Arguments for and against Therapeutic Cloning
Slide from Chris Paine’s
http://www.slideshare.net/diverzippy/biok-notes-11-introduction-to-
cells?ref=http://bioknowledgy.weebly.com/11-introduction-to-cells.html

17. Looking at the future(?): Induced pluripotent cells
https://youtu.be/i-QSurQWZo0
http://learn.genetics.utah.edu/content/stemcells/quickref/ips-cells.jpg
https://vimeo.com/77546203