1. Introduction to Cells 1.1.7 Stem Cells
1.1.8 Use of Stem Cells to treat disease
1.1.9 Ethical issues with using stem cells

2. 1.1.7 Stem Cells
Stem cells are unspecialized cells that can give rise to a wide range of body cells by differentiating along different pathways.
They retain the capacity to divide indefinitely (can self-renew), and have the potential to differentiate into specialized cell types when given the right stimulus.
However, not all stem cells can give rise to all body cells. 

3. Differentiated cells produced
Types of cells that can be produced from different types of stem cells.
Type of stem cell
Differentiated cells produced
Totipotent stem cells (e.g. the 8 cells of the morula).
Can differentiate into any type of cell including the extra-embryonic and placental cells.
Can give rise to a complete organism.
Pluripotent stem cells (e.g. embryonic stem cells of the blastocyst).
Can differentiate into all body cells, but cannot give rise to a whole organism.
Multipotent stem cells (e.g. umbilical cord stem cells).
Can differentiate into a few closely-related types of body cell.
Unipotent stem cells.
Can only differentiate into their associated (only one) cell type. For example, liver stem cells can only make liver cells. 

4. Totipotent cells – Embryonic
About 24 hours after fertilization, the impregnated oocyte begins a series of cleavage divisions. The morula is about 16 cells big.
Zygote hrs. after insemination
Embryo ~24 hrs. after insemination
Embryo ~45 hrs. after insemination
Embryo ~72 hrs. after insemination
Morula ~96 hrs. after insemination
The cells of the morula are totipotent, and can differentiate into any type of cell, and give rise to a new organism.

5. Formation of the Morula

6. Pluripotent Stem Cells – Embryonic
Can differentiate into any type of body cell.
Not embryonic or placental cells.
Arise from embryonic stem cells of the blastocyst, more specifically the inner cell mass.

7. Pluripotent Stem Cells – Embryonic
Most scientists use the term pluripotent to describe stem cells that can give rise to cells derived from all three embryonic germ layers—mesoderm, endoderm, and ectoderm.
These three germ layers are the embryonic source of all cells of the body .
Embryonic Germ Layer
Differentiated Tissue
Endoderm
Thymus Thyroid, parathyroid glands Larynx, trachea, lung Urinary bladder, vagina, urethra Gastrointestinal (GI) organs (liver, pancreas) Lining of the GI tract Lining of the respiratory tract
Mesoderm
Bone marrow (blood) Adrenal cortex Lymphatic tissue Skeletal, smooth, and cardiac muscle Connective tissues (including bone, cartilage) Urogenital system Heart and blood vessels (vascular system)
Ectoderm
Skin Neural tissue (neuroectoderm) Adrenal medulla Pituitary gland Connective tissue of the head and face Eyes, ears

9. Multipotent Stem Cells – Adult tissue/umbilical chord
Multipotent stem cells can only differentiate into closely related types of body cells.
Has limited ability to differentiate.
Specialization potential is limited to one or more cell lines.
Limited in numbers.
Examples of multipotent stem cells:
Brain stem cells that give rise to different neural cells and glia or haematopoietic cells, which can give rise to different blood cell types, but they cannot create brain cells.
Bone marrow also contains multipotent stem cells that give rise to all blood cell types but not other cells.
Mesenchymal stem cell can give rise to several cell types. This particular stem cell has been found to give rise to bone, muscle, cartilage, fat, and other similar tissues.
It is thought that they are in most body organs, where they replace diseased or aged cells.

10. Unipotent Stem Cells
Refers to a cell that can differentiate along only one lineage.
Has the capacity to differentiate into only one type of cell or tissue.
Has the lowest differentiation potential. 
Has self-renewal properties.
Skin cells, which are in the epithelium, are one of the most abundant types of unipotent stem cells. 
By taking a portion of a patient's own undamaged skin stem cells, sheets of skin can be developed for transplanting over burned areas of the patient's body.

11. Unipotent Stem Cells
Sources of adult stem cells have been found in the bone marrow, blood stream, cornea and retina of the eye, the dental pulp of the tooth, liver, skin, gastrointestinal tract, and pancreas.

12. Induced Pluripotent Stem Cells

14. 1.1.8 Use of Stem Cells to Treat Disease

15. Stargardt’s Disease What is it?
Stargardt's Disease is an inherited form of juvenile macular degeneration (affects a small area near the center of the retina) that causes progressive loss of central vision.
How common?
1 in 8,000 to 10,000.
Cause?
Recessive genetic mutation in gene ABCA4, which causes an active transport protein on photoreceptor cells to malfunction. This ultimately causes the photoreceptor cells to degenerate.

16. Stargardt’s Disease
Patients are given retinal cells derived from human embryonic stem cells, which are injected into the retina. The inserted cells attach to the retina and become functional. However, this treatment is still at the stage of limited clinical trials, but is likely to be in usage in near future.

17. Leukemia
What is it?
Cancer of the blood or bone marrow, is caused by abnormally high levels of abnormal white blood cells.
Treatment in this case involves harvesting Hematopoetic Stem Cells (HSCs) from bone marrow, peripheral blood or umbilical cord blood.
HSC cells may come either from the patient or from a suitable donor.
The patient then undergoes Chemotherapy and radiotherapy to terminate the diseased white blood cells. The next step involves transplanting back HSCs into the bone marrow where they differentiate to form new healthy white blood cells.

18. http://www. cancercenter
lymphocytic-leukemia/

20. 1.1.9 Ethical Issues of Therapeutically Use of Stem Cells
Specially created embryos
Umbilical cord blood
Adult’s own tissue
Has a higher risk of giving rise to tumor formation.
The risk of tumor formation is much lower.

21. 1.1.9 Ethical Issues of Therapeutically Use of Stem Cells
Specially created embryos
Umbilical cord blood
Adult’s own tissue
Extraction of the stem cells involves the death of the embryo. Is it fair to terminate one life to save another person?
The umbilical cord is normally discarded after birth; hence using it to harvest stem cells does not seem to cause major concern.
If the person consents to the extraction of stem cells, it should not cause any problem as far as he/she has been given all the necessary information before making the decision.

22. 1.1.9 Ethical Issues of Therapeutically Use of Stem Cells
Specially created embryos
Umbilical cord blood
Adult’s own tissue
Has unlimited potential when it comes to the different types of cells that can be created (all body cells can be generated).
Can give rise to a limited number of cell types.

23. 1.1.9 Ethical Issues of Therapeutically Use of Stem Cells
Specially created embryos
Umbilical cord blood
Adult’s own tissue
Stems cells are less likely to have accumulated mutations or genetic damage.
Has a higher chance of containing genetic damage due to accumulated mutations during the lifetime of the individual.

24. 1.1.9 Ethical Issues of Therapeutically Use of Stem Cells
Specially created embryos
Umbilical cord blood
Adult’s own tissue
It might not be compatible with the patient as it comes from another person. Therefore the patient might need to go on immuno-suppressant drugs.
The cells produced from these stem cells will be fully compatible and pose no problem of rejection (provided the umbilical cord used belongs to the patient).

25. Some arguments supporting the special creation of embryos for the harvest of stem cells:
Cells may be used in cell therapy (replacing bad cells with good ones) to eliminate serious diseases or disabilities in the human population.
It eliminates the risks of rejection of transplants made from these stem cells as they will be made up of cells which are genetically identical to the parent. 
Transplants can be easily obtained without requiring the death of another human or inflicting any kind of pressure on normal body functioning which happens when someone donates an organ.
The stem cells are harvested from the embryo at an early stage when the embryo has not yet developed a nervous system and thus it is not likely to feel any pain.

26. How to produce stem cells that correspond to those of the patient.
These are ultimately used to generate specialized tissues that can be transplanted into the patient without any problem of rejection. By looking through the different steps involved, you will understand why people question this method of obtaining stem cells.

27. Welcome to IB Bio Courtroom
Plaintiff
Prosecuting team:
You are suing the State of Arkansas for using taxpayers money to fund human embryonic stem cell research.
You will be questioning the ethics of such research.
Defense
Defense Attorneys:
Your job is to convince the jury that research should be funded by the state as long as ethical procedures are not being violated, and benefits outweigh the risks.
Expert Witnesses
International Society for Stem Cell Research
Stem cells ethical misconduct (ex. South Korea)
USA use and regulations for stem cell research
Stem cells gone wrong
Stem cells lawsuits
Your task is to go home and do an extensive research on the topic you have been assigned. Any evidence used in court must be cited during court procedures, and turned in as part of your exhibit. Evidence not properly cited will be dismissed by the judge. Both parties will be given the opportunity to cross examine the witnesses. Plaintiff and defense will be given 15 minutes prior to courtroom proceedings.