Using Stem Cells • A stem cell is a cell that can continuously divide and

differentiate into various tissues.• Some stem cells have more potential to differentiate

than others.• Adults’ bodies have some multipotent cells that can

be removed, frozen or cultured, and used for medical treatments.

• The cells of new embryos have more potential uses.• The use of embryos for stem cell research poses

ethical problems.• An alternative source of embryonic stem cells is

through SCNT (somatic cell nuclear transplant).

What are Stem Cells?Stem Cells are extraordinary because:• They can divide and make identical copies of themselves over and over

again (Self-Renewal)• Remain Unspecialized with no

‘specific’ function or become . . . .• Specialized (Differentiated) w/ the

potential to produce over 200 different types of cells in the body.

The Major Types of Stem Cells

A. Embryonic Stem Cells

• From blastocysts left over from In-Vitro Fertilization in the laboratory

• From aborted fetuses

B. Adult Stem Cells

• Stem cells have been found in the blood, bone marrow, liver, kidney, cornea, dental pulp, umbilical cord, brain, skin, muscle, salivary gland . . . .

http://commons.wikimedia.org/wiki/Image:Stem_cells_diagram.png

Advantages and Disadvantages to Embryonic and Adult Stem Cells.Embryonic S.C. Adult S.C.

“Pluripotent”(can become any cell)

“Multipotent”(“can become many but

not any”)Stable. Can undergo many cell divisions.

Less Stable. Capacity for self-renewal is limited.

Easy to obtain but blastocyst is destroyed.

Difficult to isolate in adult tissue.

Possibility of rejection?? Host rejection minimized

Reprinted with permission of Do No Harm. Click on image for link to website. http://www.pbs.org/newshour/bb/science/jan-june14/stemcells_01-29.html

• http://www.youtube.com/watch?v=7QlWBnL0zjU

Why is Stem Cell Research So Important to All of Us? Stem cells allow us to study how

organisms grow and develop over time.Stem cells can replace diseased or

damaged cells that can not heal or renew themselves.

We can test different substances (drugs and chemicals) on stem cells.

We can get a better understanding of our “genetic machinery.”

What Human Diseases are Currently Being Treated with Stem Cells?

• Parkinson’s Disease• Leukemia (Bone Marrow Transplants)• Skin Grafts resulting from severe burnsStem Cell Therapy has the Potential to:• Regenerate tissues/organs• Cure diseases like diabetes, multiple

sclerosis, etc.

Why the Controversy Over Stem cells?• Embryonic Stem cells are derived from

extra blastocysts that would otherwise be discarded following IVF.

• Extracting stem cells destroys the developing blastocyst (embryo).

-Questions for Consideration-Is an embryo a person?Is it morally acceptable to use embryos

for research?When do we become “human beings?”

Key Concept Questions• How are transgenic organisms useful to human

beings? – Genetic engineering has spurred the growth of

biotechnology, a new industry that is changing the way we interact with the living world

• How are cloning and stem cell research related?– Cloning can produce organisms that are

genetically identical to preexisting individuals. Stem cells can be used to grow new tissues.