Title: Stem Cells: Myths, Facts, and Ethics
1Stem Cells Myths Facts and Ethics
- Xinyu Zhao PhD
- Assistant Professor
- UNM School of Medicine
- Department of Neuroscience
2The 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.
3Part I The myths and facts of stem cell
researchPart 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
6Differences 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.
7Source of ES cells
Pluripotent ES cells
8Human ES cells
Human blastocyst
Inner cell mass
Mouse fibroblasts feeder layer
9ES cells
Differentiation
10(No Transcript)
11Applications of Human pluripotent stem Cells
- Basic Knowledge of Human Development
- Models of Human Disease
- Transplantation-Cell Replacement
- Drug Development
- Organogenesis
12Scientific 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
13The 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.
14Somatic 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
16Therapeutic cloning Studying Mechanisms of
Diseases Example ALS
Human ES Cells Studying the Cellular and
Molecular Mechanisms of Disease
17Mark Denham Richard Mollard
18Not This
19The 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.
20induced pluripotent cells (iPSC) A combination
of several genes can re-program skin fibroblasts
into pluripotent cells
- 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)
21The 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.
22People 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 8.2 Million
- Alzheimers disease 4 Million
- Parkinsons disease 1.5 Million
- Burns (severe) 0.3 Million
- Spinal cord injuries 0.25 Million
- Birth defects 150000 (per year)
- Total 128.4 Million
- --------------------------------------------------
------------------------------------ - Data from the Patients Coalition for Urgent
Research Washington DC (according to Perry
Ref. 267).
23The 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
24The 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!!!
25The 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.
26Other 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
27How 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
28Useful Resources
- National Institute of Health resource for stem
cells (http//stemcells.nih.gov) - International Society for Stem Cell Research
Guidelines for the Conduct of Human Embryonic
Stem Cell Research (www.isscr.org) - National Academy of Science Guidelines for
human embryonic stem cell research
(http//www.nap.edu/openbook.phpisbn0309096537)
29- On March 9 2009 President Obama issued
Executive Order 13505 entitled Removing
Barriers to Responsible Research Involving Human
Stem Cells.
30Thank you !
