Stem Cells and Cell Differentiation

1. What are Stem Cells?

a. Stem cells are different from all other cells in the body.

b. Stem cells have 2 distinct properties:1. They are unspecialized cells that are

capable of renewing (regenerating) for long periods of time.

2. They can give rise to different types of somatic cells (specialized body cells).

Stem Cell Differentiation

http://stemcells.nih.gov/info/basics/basics4.asp

2. Types of Stem Cells

a. Embryonic1. Obtained from in

vitro fertilization, or aborted embryos

2. 3 or 4 day old embryo; blastocyst stage

3. Source of controversy

2 types of Stem Cells

a. Adult1. Found among some

differentiated cells in a specific tissue or organ; placental cord; baby teeth

3. Unique Properties of Stem Cellsa. Regeneration

i. Stem cells can replicate themselves over longer periods of time than other body cells

b. Differentiationi. Stem cells are unspecialized

cells that can produce specialized body cells by first producing an intermediary cell

http://www.kumc.edu/stemcell/images.html

3. Unique Properties of Stem Cells

ii. Stem cells differentiate by the activation of certain genes in DNA.iii. The genes that are activated determine the type of cell the stem cell will become.

Pluripotent Differentiation

http://www.kumc.edu/stemcell/images.html

http://www.stemcellresearch.org/testimony/20040929prentice.htm Reprinted with permission of Do No Harm.

4. Potential Uses of Stem Cell Research

a. Cell based therapies:1. Regenerative therapy to treat

Parkinson’s, Alzheimer’s, ALS, spinal cord injury, stroke, severe burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis

2. Stem cells in therapeutic cloning3. Stem cells in cancer

5. Cloning

a. Reproductive Cloning1. Producing new organisms genetically identical to

donor

b. Therapeutic Cloning1. Make a therapeutic product (vaccine, human

protein etc.)2. Deliver organs that will not be rejected3. Act as animal models for human disease

c. Breeding animals or plants with genetically favorable traits (genetic engineering)

6. Debate in USa. Federal funding available for research is

strictly limitedi. ES cell lines that were already in existence by

8/9/01ii. Federal funding cannot be used on new

embryonic stem cells

b. Private companies continue to pursue stem cell research

i. No federal funding

7. Differentiation due to Environmental Factorsa. Some cells differentiate

due to environmental factors.

b. Many disorders and diseases are the result of environmental differentiation

i. Cancer

ii. Fetal Alcohol Syndrome

iii. Mesothelioma

Summary

Stem Cell Review Film Clip

References Stem cells & Cloning Stem cells & Cloning; David A.

Prentice, Benjamin Cummings, 2003 http://www.pbs.org/wgbh/nova/sciencenow/

3302/06.html http://www.stemcellresearch.org http://www.stemcells.nig.gov/info/nasics/nasics7.asp http://www.stemcells.nig.gov/info/scireport/

2006report.htm http://www.whitehouse.gov/news/releases/

2001/08/20010809-2.html Stem cells in class; Badran, Shahira; Bunker Hill

Community College, 2007, Boston Museum of Science Biotechnology Symposium

Harvard Stem Cell Institute