1. Stem Cells: Myths, Facts, and Ethics
Anthony D’Ascoli
PHI 2604

2. The ethical hot spots of stem cell research
Human embryonic stem cells isolated from blastocyst stage human embryos
Cloning by somatic nuclear transfer
Induced pluripotent stem cells derived from human skin cells.

3. Part I: The myths and facts of stem cell research Part II: The ethics of stem cell research

4. Definition of stem cells:
Self-renewal
Multi-potency

5. Totipotent Totipotent Totipotent
Lineage restricted Limited self-renewal

6. Differences between embryonic stem cells and adult stem cells
They have different self-renewal capabilities
Embryonic stem cells: near indefinite self-renewal
Adult stem cells: limited self-renewal
They have different differentiation potentials
.Embryonic stem cells: differentiate into all cell types in an organism
Adult stem cells: differentiate into restricted cells types.
They differ in how they respond to external stimuli
Embryonic stem cells are readily to change upon stimulation
Adult cells emphasize on stability and need to be activated by cues, e.g. injuries.

7. Source of ES cells
Pluripotent
ES cells

8. Human blastocyst Human ES cells Inner cell mass
Mouse fibroblasts feeder layer

9. ES cells
Differentiation

11. Applications of Human pluripotent stem Cells
Basic Knowledge of Human Development
Models of Human Disease
Transplantation-Cell Replacement
Drug Development
Organogenesis

12. Scientific Challenges of Using Human ES Cells:
Challenges to cell-replacement and organ transplantation therapies:
Lack of cell type specific differentiation
Possible tumor formation
Immune rejection by recipients
Challenges to ES cells as models for studying human diseases
Do not know the genes responsible for the diseases
Can not create the mutations corresponding to human diseases

13. The ethical hot spots of stem cell research
Human embryonic stem cells isolated from blastocyst stage human embryos
Cloning by somatic nuclear transfer
Induced pluripotent stem cells derived from human skin cells.

14. Somatic cell nuclear transfer (SCNT)
For establishing and studying models of human diseases
For generating patient-specific cells/organs for transplantation and repair

15. Therapeutic Cloning: Organogenesis

16. Therapeutic cloning: Studying Mechanisms of Diseases
Example: ALS
Human ES Cells: Studying the Cellular and Molecular Mechanisms of Disease

17. D B E C F A
Mark Denham & Richard Mollard

18. Not This

19. The ethical hot spots of stem cell research
Human embryonic stem cells isolated from blastocyst stage human embryos
Cloning by somatic nuclear transfer
Induced pluripotent stem cells derived from human skin cells.

20. Why iPSC can not replace ESC research:
induced pluripotent cells (iPSC) A combination of several genes can re-program skin fibroblasts into pluripotent cells
“Reprogramming”
Why iPSC can not replace ESC research:
Studying ESCs is critical for understanding iPSCs
iPSCs are induced by cancer genes therefore hinder their use for therapies
(Takahashi and Yamanaka Cell 2007, Yu Science 07, Cowan Science 07, Wernig Nature 07, Okita Nature 07)

21. The ethical hot spots of stem cell research
Human embryonic stem cells isolated from blastocyst stage human embryos
Cloning by somatic nuclear transfer
Induced pluripotent stem cells derived from human skin cells.

22. People in the US affected by diseases that may be helped by stem cell research
Condition Number of Persons Affected
Cardiovascular diseases 58 Million
Autoimmune diseases 30 Million
Diabetes 16 Million
Osteoporosis 10 Million
Cancer Million
Alzheimer's disease 4 Million
Parkinson's disease 1.5 Million
Burns (severe) Million
Spinal cord injuries Million
Birth defects 150,000 (per year)
Total Million
Data from the Patients' Coalition for Urgent Research, Washington, DC (according to Perry, Ref. 267).

23. The 1st ethical hot spot of stem cell research
Human embryonic stem cells isolated from blastocyst stage human embryos
“In the case of embryonic stem cell research, the end that scientists hope to achieve is the relief of human suffering. That this is a humanitarian and worthy end is not in dispute. The controversy is about the means, namely, the consumption of donated embryos.” -- ISSCR website on stem cell ethics

24. The 2nd ethical hot spot of stem cell research
Cloning by somatic nuclear transfer
International Guideline for Stem Cell Research (by ISSCR Stem Cell Ethics Committee):
Reproductive cloning is prohibited!!!

25. The 3rd ethical hot spot of stem cell research
Induced pluripotent stem cells derived from human skin cells.
Protection of human subjects
Informed consent
Protection of genetic identity.

26. Other Related Ethical Issues
Ethical issues in human clinical trials
Informed consent of patients
Protection of human subjects.
Protection of human genetic and cellular materials
Creating human/animal hybrid stem cells
Ethical issues in animal research.
Honest and integrity in biomedical research

27. How can scientists ensure ethical conduct in stem cell research
Education for researchers
Routine emphasis by principle investigators
Emphasis by funding agencies
Classes and seminars
Education for the public
Understand the importance of research
Understand that scientists are under ethical guidance
Communication and open dialogue
Understand each others’ opinion
Reach a rationale common ground.
Last step: Legal reinforcement

28. Useful Resources
National Institute of Health resource for stem cells (
International Society for Stem Cell Research: “Guidelines for the Conduct of Human Embryonic Stem Cell Research (
National Academy of Science: “Guidelines for human embryonic stem cell research” (

29. On March 9, 2009, President Obama issued Executive Order 13505, entitled "Removing Barriers to Responsible Research Involving Human Stem Cells."