1. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Summer 2007 Workshop in Biology and Multimedia for High School Teachers

2. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Stem Cells in Biology An Introduction to Stem Cells and Stem Cell Applications for English Learners Andrew Creamer

3. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Objectives Define and describe the characteristics of embryonic and adult stem cells Describe the origins of various stem cells Describe the debate surrounding and identify misconceptions about stem cell research Describe the present and future applications for stem cell research

4. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. What makes a cell a stem cell? Plasticity: A stem cell is plastic, meaning it can develop into another type of cell. Differentiation: The process where a stem cell specializes or develops into another type of cell. Self-Renewal: a stem cell can divide (renew itself) indefinitely (go through mitosis) and without always developing into another cell.

5. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Self-renewal Stem Cell CellStem Differentiation

6. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Differentiation http://stemcells.nih.gov/info/basics/basics4.asp "Image courtesy of NIH resource for stem cell research"

7. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Major Types of Stem Cells Embryonic Stem Cells Totipotent : cell can develop into all cell types “Immortal”: can self- renew indefinitely Plentiful Adult Stem Cells Multipotent: cell can develop into a few cell types but not all Located in few organs or may be unidentified Hard to find

8. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Embryonic Stem cells Embryos are formed in labs that help couples get pregnant. An egg and sperm fertilize a zygote and are inserted into a woman’s uterus to develop into an embryo and then fetus. http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=HUMN150B&File_type=GIF

9. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. In Vitro Fertilization (IVF): a sperm fertilizes an egg in a lab dish creating the embryo. http://en.wikipedia.org/wiki/Image:Icsi.JPG

10. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Embryonic Stem Cells This process creates multiple embryos that will not be used to make a baby. Many donors wish to donate these unused embryos to scientific research instead of having the lab throw them away. http://en.wikipedia.org/wiki/Polar_bodies First stages of segmentation of a mammalian ovum. Semidiagrammatic. z.p. Zona striata. p.gl. Polar bodies. a. Two-cell stage. b. Four-cell stage. c. Eight-cell stage. d, e. Morula stage.

11. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Embryonic Stem Cells The embryo used in research is 4-5 days old and is a microscopic ball of about 150 cells. The ball as thick as a hair is called a Blastocyst and has three layers called germ layers. Each layer has special stem cells that makes a part of the body. http://en.wikipedia.org/wiki/Image:Blastocyst.svg

12. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Blastocyst: Source of Embryonic Stem Cells http://en.wikipedia.org/wiki/Image:Blastocyst%2C_day_5.JPG Blastocyst under the microscope

13. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Germ Layers The embryo develops three germ layers of cells called the ectoderm, mesoderm and endoderm http://en.wikipedia.org/wiki/Image:Gastrulation.png

14. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Embryonic Stem Cell These embryos not used in IVF will not grow into a fetus or baby because an embryo like the one in the picture needs to be implanted inside a woman’s uterus to develop into a human fetus. Fetuses and babies are not aborted for stem cell research. AuthorPhotograph by Ed Uthman, MD.PermissionPD Public domain http://en.wikipedia.org/wiki/Image:Tubal_Pregnancy_with_embryo.jpg.

15. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Embryonic Stem Cells Embryos can also be used for cloning research. The process called Somatic Nuclear Transfer (SNT) removes an embryo’s nucleus and replaces it with another person’s adult cell nucleus. The embryo would then have the ability to develop into a clone or genetic copy of the nucleus donor if the embryo were implanted into a woman’s uterus. http://en.wikipedia.org/wiki/Image:Icsi.JPG

16. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Dolly the Sheep was first cloned using SNT. An adult sheep body cell nucleus was implanted into an embryo and then implanted in a mother sheep’s uterus. http://en.wikipedia.org/wiki/Image:Dollyscotland.JPG

17. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Adult Stem Cells Adult stem cells are called somatic or body stem cells. Some people call these adult because they are found after an embryo develops into a fetus and are no longer an embryonic stem cell. Not only adults have adult stem cells! Some organs are believed to lack stem cells and these cells grow and replace dead cells with mitosis. http://en.wikipedia.org/wiki/Image:Mitosis-flourescent.jpg

18. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Adult Stem Cells Adult stem cells develop into a few cell types. These multipotent cells are used in bone-marrow transplants and will develop into all the blood cells. These cells are important, but some organs may not have adult stem cells and these cells can be difficult to find. http://www.ulb.ac.be/sciences/biodic/homepage2.htmhttp://www.ulb.ac.be/sciences/biodic/homepage2.htm red corpuscles figurel

19. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. All Stem Cells Are Important All stem cells can help scientists learn how cells regenerate or repair injured cells, tissues and organs. Scientists need both types of stem cells for their research. Each cell type can help inform scientists on how we develop and how some diseases affect our cells.

20. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Stem Cell Debate Some people oppose stem cell research because they believe that the 4-5 day old ball of cells is a living human being. What some do not understand is that unused embryos are trashed regardless. Many people, religious and non- religious, believe it is better to use these embryos for research on how to cure human diseases rather than to just trash them without purpose. The underlying issue is the personal belief when life actually begins.

21. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Misconceptions Pregnancy, fetuses or babies are aborted or harmed in stem cell research. Fact: Fertilized Blastocysts donated from IVF labs are used and no pregnancy is aborted. The fertilized embryos are removed from women’s bodies and used for research. Fact: The embryos are left over from IVF and are frozen and are not implanted for pregnancy.

22. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Misconceptions A clone is grown in a lab without an embryo or born from a mother and is the same age and personality as you, and has no belly button. Fact: a clone would need a fertilized embryo and would have to be implanted in a woman’s uterus. If you were cloned at 14, the clone would be 14 years younger than you (a baby you) and would have to have a mother to be born, so yes, it would have a belly button. http://en.wikipedia.org/wiki/Image:Femnavel.jpg

23. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Misconceptions If the embryos were not used in stem cell research they would have been used to make children. Fact: The embryos left over from IVF are discarded. Men and women who donate their embryos do not know that their embryos are used for research. Fact: The embryos used in scientific research are donated with written and informed consent (permission) by the donors.

24. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Stem Cell Research Some scientists want to identify the genes and processes used in embryo development to figure out how to make new cells in damaged or diseased cells and organs or fix old cells by reprogramming them to be young cells again.

25. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Cell-Based Therapy http://stemcells.nih.gov/info/basics/basics6.asp

26. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Cell-Based Therapies Science has known for a long time that certain organisms and organs can regenerate or re-grow themselves after being damaged or injured. For example, planaria can regenerate after being cut up into small pieces and certain lizards can regenerate limbs and tails. Scientists want to know “How do they do it?” and study these animals in the lab. Using cells to medically regenerate or replace dead or injured cells is an example of a cell-based therapy.

27. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Planaria can regenerate lost cells http://en.wikipedia.org/wiki/Image:Smed.jpg http://creativecommons.org/licenses/by-sa/2.5/

28. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Cell-Based Therapy If your skin was burned in an accident, there would be layers of skin cells that die. Using stem cell techniques, scientists could take a skin cell from another area on your body or stem cell and grow new plates of skin tissue in a lab tissue culture dish to regenerate new skin cells for you. http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=HUMN164B&File_type=GIF

29. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Future Applications Stem Cells may one day help scientists to regenerate cells lost in diseases like: Repair heart muscle after a heart attack Pancreas cells lost in diabetes Neurons lost in Alzheimer’s Retinal cells causing blindness Understand the cell growths of cancers Help organ transplantation