1. Stem Cells

2. The Stem Cell Concept
A stem cell is an undifferentiated, dividing cell that gives rise to a daughter cell like itself and a daughter cell that becomes a specialized cell type.

3. What Is a Stem Cell? Unspecialized cells
Give rise to more than 225 specialized cells in the body
Serve as the body’s repair system
Renew itself
Replenish other cells

4. In Summary: Two Major Types of SC
Mature Stem Cells
Early Stem Cells
a.k.a. Adult (includes umbilical cord & placenta)
a.k.a. Embryonic; blastocystic
Cells obtained from specific mature body tissues, umbilical cord, placenta
Cells obtained from inner cell mass of a blastocyst
Multipotent — Give rise to multiple but limited cell types
Pluripotent — Flexible, give rise to any cell type in the body

5. What Are the Sources of Mature Stem Cells?
Mature Body Tissues

6. Stem Cells are Found in the Adult, but the Most Promising Types of Stem Cells for Therapy are Embryonic Stem Cells

7. Where Are Early Stem Cells Found?
Who did it first?
In 1998, U. Wisconsin research team isolates stem cells from IVF-blastocysts
5 days of
development

8. The Inner Cell Mass is the Source of Embryonic Stem Cells
The embryo is destroyed by separating it into individual cells for the collection of ICM cells.

9. How Big Is a Blastocyst?

10. What Are the Characteristics?
Early stem cells are pluripotent
Retain the special ability to develop into nearly any cell type
teratoma

11. Teratoma

13. Additional Potential Dilemmas – Therapeutic Cloning to Obtain Matched Embryonic Stem Cells
Cultured mouse embryonic stem cells.
Cells from any source other than you or an identical twin present the problem of rejection.
If so, how can matched embryonic stem cells be obtained?
A cloned embryo of a person can be made, and embryonic stem cells harvested from these clones.

14. Some Thorny Ethical Questions
Are these masses of cells a human?
Is it ethical to harvest embryonic stem cells from the “extra” embryos created during in vitro fertilization?

17. Somatic Cell Nuclear Transfer (SCNT)
Sometimes referred to as
“therapeutic cloning”

18. SCNT: Asexual Reproduction
No sperm involved
Transfers nucleus from a mature cell into a donor egg
Requires electric or chemical stimulus to begin dividing
Functionally different from regular fertilized egg

19. What Should You Know About SCNT?
Purpose:
Find cures and therapies for diseases
Awaken the natural capacity for self-repair that resides in our genes
Potential Results:
Patients will receive own stem cells to treat disease
No need for donor match
Like transplantation, but without rejection

20. How Would SCNT Treat Disease?

21. What Should You Know About SCNT?
No reputable scientist wants to clone human beings
SCNT stem cells are alive in a Petri dish
Unless implanted in uterus, you can not generate a fetus
Evidence suggests that SCNT stem cells may never develop into a human even when implanted

22. The Biotechnology of Reproductive Cloning
Even under the best of circumstances, the current technology of cloning is very inefficient.
Cloning provides the most direct demonstration that all cells of an individual share a common genetic blueprint.

23. Therapeutic Cloning
Is there any ethical difference between therapeutic and reproductive cloning?

24. The Next Step? Highly unlikely.
Attempts at human cloning are viewed very unfavorably in the scientific community.

26. Both Kinds of SCR are Needed
Mature Stem Cells
Early Stem Cells
First isolated in 1960s
First isolated in 1998
50+ years of research
9 years of research
Federal Funding = >$2.7 Billion (FY02-06)
Federal Funding = $132 Million (FY02-06)
Results: 50+ human therapies
Results: Only in animal trials; No human trials

27. What Are the Current State Restrictions?

28. Which States Currently Support ESCR?