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……

KEY STAGE 3REVISIONCan you fill in the missing gaps…

TASK INSTRUCTIONS

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)

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

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.

skin

liver

nervered blood

stem

stem

Humans start with 1 cell, which divides over and over to produce a baby…

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.

Blastocyststem cell

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.

EMBRYONICSTEM CELLS

KEY FACT: embryonic stem cells which are unspecialised cells that can develop into any type of cell. Only found in early stages of life.

Specialised cells cannot divide, and after a while they die and must be replaced by stem cells which have divided.

Blood cell 120 days

Adult stem cells are used to repair body tissues e.g. skin in the same area of the body in which they are found.

For example bone marrow stem cells turn into any of the usual blood cells found in the body (differentiates)

platelet

whiteblood

red bloodadultstem

stem

New developments in gene therapy have shown that we can turn an adult stem cell into an embryonic stem cell by reprogramming it.

ADULTSTEM CELLS

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.

Adult stem cell

Nucleus splits

Cell splits

Hairless skin cell

Embryonic stem cell

New skin cell with hair!

SKIN GRAFTSSkin 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.

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.

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.

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…

Hairless skin cell

Embryonic stem cell

New skin cell (hair generating)

BALDNESS

Transplants cannot prevent previous hormonal/protein type problems which can reoccur. Transplants can only be permanent if the underlying problems are fixed.

Red and Yellow Bone Marrow from ball at top of femur (thigh bone)

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.

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.

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.

BONE MARROW

Cells inside the eye can stop working for a variety of reasons; damage, infections, excess pressure inside the eye and diabetes.

BLINDNESS

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)

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.

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.

REVIEW OF STEM CELLS

Focus Condition(s) Stem Cell Treatment Problems

Skin Cells Trials Embryonic but patient can donate their own skin

Hair Cells

Red/White blood cells & platelets

(Bone Marrow)

Chemotherapy / Radiotherapy, infections,

wrong number of cells growing

Retina (eye) cellsCan be rejected by the patient so need to take

strong drugs to prevent this

ADULT STEM CELLS: EMBRYONIC STEM CELLS:

REVIEW OF STEM CELLS

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 DonorCan 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

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.

QUICK CHECK

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)

REVISION/& TEST

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 (Skin Cells)

1 TL (Hair Cells)

1 TL (Bone

Marrow)

1 TL (Eye Cells)

2 (Skin Cells)

2 (Hair Cells)

2 (Bone

Marrow)

2 (Eye Cells)

3(Skin Cells)

3(Hair Cells)

3(Bone

Marrow)

3(Eye Cells)

4(Skin Cells)

4(Hair Cells)

4(Bone

Marrow)

4(Eye Cells)

5(Skin Cells)

5(Hair Cells)

5(Bone

Marrow)

5(Eye Cells)

6(Skin Cells)

6(Hair Cells)

6(Bone

Marrow)

6(Eye Cells)

GROUPS

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.