Transcript Slide 1

Mr Powell
Lesson Outcomes…
1. I will be able to give examples of how stem cells can be used to treat illnesses (Basic)
2. I will be able to explain the differences between how adult stem cells and embryonic
stem cells work. (Medium)
3. I will be able to explain which type of stem cell is suitable for certain treatments and
why. (Harder)
The small blocks are ok but when they grow up……
Can you fill in the
missing gaps…
1) Summarise this sheet
of information into a
short paragraph and put
it here. (Basic)
2) Summarise this
sheet of information
into a short paragraph
and put it here. (Basic)
Total Time
15 mins
3) Use your applications of stem cells sheet to fill in the relevant
row.
4) Prepare an oral (spoken) presentation to the rest of the class
which lasts 1 minute to complete the sheet. You may use my
ready made PPT slides as well. (Harder)
KEY FACT: embryonic stem cells which are unspecialised cells that
can develop into any type of cell. Only found in early stages of life.
Humans start with 1 cell, which divides over
and over to produce a baby…
Embryonic stem cells replicate to produce any specialised
cell (differentiate). Adult stem cells are different as they
only produce one type of specialised cell in the area of the
body that they are found.
red blood
stem
nerve
liver
skin
An Embryonic stem cell is found in a
blastocyst (5 day old embryo). A Blastocyst
contains around 100 stem cells in total. These
cells are unspecialised and can replicate into
any type of specialised cell.
stem cell
Blastocyst
Embryonic stem cells can be harvested.
We can use discarded embryos from
fertility treatments (controversial with
many religious groups). They can be
controlled in a lab to form a specialised
cell of the scientists choosing which is
then altered or implanted into a patient
with an illness.
stem
Adult stem cells are used to
repair body tissues e.g. skin in
the same area of the body in
which they are found.
red blood
adult
stem
For example bone marrow stem
cells turn into any of the usual
blood cells found in the body
(differentiates)
white
blood
platelet
stem
Adult stem cell
Specialised cells cannot divide, and
after a while they die and must be
replaced by stem cells which have
divided.
Nucleus splits
Blood cell
120 days
New developments in gene therapy
have shown that we can turn an adult
stem cell into an embryonic stem cell by
reprogramming it.
Embryonic stem cell
New skin
cell with
hair!
Hairless skin cell
Cell splits
KEY FACT: adult stem cells are unspecialised cells that can develop into many, but
not all, types of cells. They are found in certain areas of the body only.
Skin grafts have been used for centuries,
although no one knew exactly why they
worked until fairly recently.
Skin is particularly rich in stem cells.
Because so much skin is lost through
normal wear and tear; you shed thousands,
or even millions, of dead skin cells every
day.
In mild cuts and burns, these stem cells
work to repair the damaged tissue. In
severe burns the stem cells in the burn area
are destroyed, so doctors have to take skin
from an undamaged area.
There is an obstacle in carrying out skin grafts, for
example; if a person suffers burns, only the skin from that
same person (from another area of their own body) could
be used for a skin graft. If doctors tried to use skin from
another person, the immune system of the person who
suffered the burns would eventually reject the graft.
In trials scientists are now trying to take a stem cell from a
person and modify it genetically to turn it into an
embryonic stem cell and then make a skin cell culture. For
example; We could then make as much skin as the person
needs to repair burns, without having to take skin from
other areas of their body.
Male baldness is mainly caused by too much of a
certain type of protein in the skin or for women a
hormonal imbalance. This is a localised effect and
can be reversed in some people.
We can take the nucleus from one cell and combine with
another cell to produce a “genetically modified cell”. It is a
complex process but shown simply here…
Adult skin stem cells with the ability to grow hairs
can be taken from another part of a persons body
(i.e. your arm). The adult skin stem cells can then
be separated from other cells in the sample by use
of a centrifuge (object which spins the sample
around). The adult skin stem cells which have been
separated from the normal cells are the only cells
which are then injected into the patients scalp and
hair growth starts again.
Transplants cannot prevent previous
hormonal/protein type problems which can reoccur.
Transplants can only be permanent if the underlying
problems are fixed.
In trials Japanese researchers took hairless mice and used
complex techniques to merge embryonic stem cells with
adult skin cells to make a new skin stem cell which would
grow hair. Then they implanted the new cells into the skins
of the mice. It took 21 days to grow the new hair structures
and roots.
Embryonic
stem cell
New skin cell
(hair generating)
Hairless skin cell
Bone marrow problems can occur when we get
infections such as tuberculosis. Sometimes the
bone marrow starts to produce too many or too
few of one type of cell. Often cancer treatments
such as radiotherapy can kill bone marrow as
well.
Bone marrow has an important job to do in the
body; the stem cells in the marrow are able to
produce exact copies of themselves as well as
being able to produce red blood cells, white cells
and platelets. We call this “differentiation”
For bone marrow treatment,
we extract adult stem cells
from a donor and then inject
them into a patient where
they differentiate.
Red and Yellow Bone Marrow
from ball at top of femur (thigh
bone)
The patient will often have a
treatment such as
chemotherapy (strong drugs) to
kill all their white blood cells
before their bone marrow
treatment so the white cells
don’t kill the donor cells.
The body of the donor
is able to replace the
bone marrow stem cells
within six weeks. After
donating, most donors
are back to their usual
routine in a few days.
A better method would be to take
adult stem cells from the patient
and engineer them into embryonic
type cells to avoid this rejection
and allow regeneration.
Cells inside the eye can stop
working for a variety of
reasons; damage, infections,
excess pressure inside the eye
and diabetes.
Stem cells can help the eye
recover by taking embryonic
stem cells from a donor embryo
and culturing them to grow into
retina type cells (found at the
back of eye).
The stem cells are then injected
into the patient.
As the cells are from a donor they
can be rejected completely or grow
into tumours (cancers) inside the
eye. Powerful drugs can help
prevent this and must be taken for
a few months after the operation.
Marcus Hilton
(first European patient)
EMBRYONIC STEM CELLS:
ADULT STEM CELLS:
Focus
Condition(s)
Stem Cell Treatment
Problems
Trials Embryonic but patient
can donate their own skin
Skin Cells
Hair Cells
Red/White blood cells &
platelets
(Bone Marrow)
Retina (eye) cells
Chemotherapy /
Radiotherapy, infections,
wrong number of cells
growing
Can be rejected by the
patient so need to take
strong drugs to prevent this
ADULT STEM CELLS: adult stem cells are
unspecialised cells that can develop into many, but
not all, types of cells. They are found in certain areas
of the body where they replicate
EMBRYONIC STEM CELLS: are cells which are unspecialised
cells that can develop into any type of cell if cultured under
the right conditions.
Focus
Condition(s)
Stem Cell Treatment
Problems
Skin Cells
Heat or chemical burns
Trials Embryonic but patient
can donate their own skin
Adult donor skin would be
rejected
Hair Cells
Baldness from hormones or
excess protein
Patient donates own + Trials
of Embryonic
Need follicles to transfer but
does not prevent underlying
previous causes
Red/White blood cells &
platelets
(Bone Marrow)
Chemotherapy /
Radiotherapy, infections,
imbalance of growth or lack
of growth
Another Adult Donor
Can be rejected by the
patient so have to kill their
own bone marrow
Retina (eye) cells
Damage, infection, lack of
growth
Trials of Embryonic only
Can be rejected by the
patient so need to take
strong drugs to prevent this
1. Give an example of how these cells can
be used to treat illnesses. (Basic)
2. Explain what is the difference between
adult stem cells and embryonic stem
cells. (Medium)
3. Give an example of a specific type of
treatment and why it needs embryonic
or adult stem cells. (Harder)
Can you fill in the
missing gaps…
Outcomes Assessment…..
1)
2)
3)
Mr Powell
Lesson Outcomes…
1. I will be able to give examples of how stem cells can be used to treat illnesses (Basic)
2. I will be able to explain the differences between how adult stem cells and embryonic
stem cells work. (Medium)
3. I will be able to explain which type of stem cell is suitable for certain treatments and
why. (Harder)
1 TL
2
3
4
5
6
(Skin Cells)
(Skin Cells)
(Skin Cells)
(Skin Cells)
(Skin Cells)
(Skin Cells)
1 TL
2
3
4
5
6
(Hair Cells)
(Hair Cells)
(Hair Cells)
(Hair Cells)
(Hair Cells)
(Hair Cells)
1 TL
2
3
4
5
6
(Bone
Marrow)
(Bone
Marrow)
(Bone
Marrow)
(Bone
Marrow)
(Bone
Marrow)
(Bone
Marrow)
1 TL
2
3
4
5
6
(Eye Cells)
(Eye Cells)
(Eye Cells)
(Eye Cells)
(Eye Cells)
(Eye Cells)
ADULT STEM CELLS: Multipotent cells have the potential to give
rise to a variety of cells. A blood stem cell that can develop into
several types of blood cells, but cannot develop into brain cells or
other types of cells.
These occur at the end of the long series of cell divisions that form
the embryo cells that are terminally differentiated, or that are
considered to be permanently committed to a specific function.
EMBRYONIC STEM CELLS: Pluripotent means the ability to divide
into all the types of cells except extra-embryonic tissues (umbilical
cord, placenta)
Zygote: Totipotency is the ability of a single cell to divide and
produce all the differentiated cells in an organism, including extra
embryonic tissues. An example would be a zygote or fertilised egg
cell at the start of life.