1. What are stem cells ?

2. Characteristics that distinguish stem cells from other cells
They are undifferentiated cells (their job is to become special cells when needed)
They can be grown continuously in a culture (stem cell line)
They can be changed (using chemicals) to become cells with special functions

3. Why the name “stem cells”

4. What controls differentiation?
When a cell becomes a special cell type
What controls differentiation?
Chemicals released by other cells
The location of the cells (the stem cell niche)

5. Day 14 still the size of a pencil tip
Cells in the blastocyst migrate to form three layers of cells.
Each of these layers are stem cells, but can only become certain types of cells.
These cells have begun to differentiate.
Day 14 still the size of a pencil tip

6. All cells have the same genes (information)
However, eye cells differ from nose cells
So how do they become different?

7. Gene Activation:
As a cell differentiates, some genes are turned on and some are turned off
Only the genes necessary to make the type of cell needed will be working.
Like a computer with all information, but only certain programs are turned on, others are off

8. Cells in the embryo continue to migrate and differentiate.
19-26 Days
Cells in the embryo continue to migrate and differentiate.
The brain and spinal cord begin to form.

9. By 4 weeks the heart is beating.
4 weeks 1/6 inch
By 4 weeks the heart is beating.
Cells are still differentiating.

10. 5 weeks 1/6 inch

11. 6-8 weeks ½ inch

12. 12-16 Weeks 2.5 inches ½ ounce

13. Two basic types of stem cells:
Embryonic stem cells (ESC)-
obtained from fertilized eggs left over from
in vitro fertilization (IVF).
Collected from the inner cell mass (ICM)
Original 30 cells yield millions of embryonic stem cells
Batches of them can be frozen and shipped to other laboratories

14. ESC’s
Scientists have "recipes" of chemicals for the differentiating ESC’s into specific cell types
approx.
30 cells

15. Adult stem cells (ASC) -
both children and adults have them in specific areas (niche)
The cells divide and differentiate when needed
One cell always remains a stem cell

16. Regenerative Medicine
Short version 2 minutes
Longer version 4 minutes