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Stem Cell Research Overview

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Stem Cell Research Overview

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  1. Stem Cell Research Overview Straight Path

  2. Outline • What are Stem Cells? • Potential Uses for Stem Cells • Cloning • Stem Cells and Cancer • Worldwide Status • What do you think? • Summary

  3. What are Stem Cells? • Stem cells are different from all other cells in the body. • Stem cells have 2 distinct properties: • They are unspecialized cells that are capable of renewing (regenerating) for long periods of time. • They can give rise to different cell types (differentiation).

  4. Stem Cell Differentiation http://stemcells.nih.gov/info/basics/basics4.asp

  5. Embryonic Obtained from in vitro fertilization, or aborted embryos 3 or 4 day old embryo; blastocyst stage Adult Found among some differentiated cells in a specific tissue or organ; placental cord; baby teeth 2 types of Stem Cells

  6. Unique Properties of Stem Cells • Regeneration • Stem cells can replicate themselves over longer periods of time than other body cells • Differentiation • Stem cells are unspecialized cells that can produce specialized body cells by first producing an intermediary cell http://www.kumc.edu/stemcell/images.html

  7. Differentiation Animation • Differentiation (http://learn.genetics.utah.edu/units/biotech/microarray/)

  8. Embryonic Stem Cells -Blastocyst Stage • 3 parts: • Trophoblast • Blastocoel (“blastoseel”) or blastocyst cavity • Inner cell mass • Millions of cells can come from one blastocyst http://www.kumc.edu/stemcell/images.html

  9. Blastocyst Vocabulary • Trophoblast - outer shell of blastocyst. • Blastocoel - fluid-filled space within blastocyst. • Inner cell mass - group of 30+ cells on one end of the blastocoel, this is what produces the specialized cells needed for adult life.

  10. Stem Cell Potential

  11. Pluripotent Differentiation http://www.kumc.edu/stemcell/images.html

  12. Adult Stem Cells (ASC) • ASCs are undifferentiated cells found among differentiated cells in a tissue or organ • They are able to regenerate and differentiate into the major cell type of the tissue or organ in which they are found. (Multipotent) • Recent experiments have raised the possibility that stem cells from one tissue/organ can create other cell types • This is known as PLASTICITY

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

  14. Adult Stem Cell Facts • Adult stem cells were found in many more tissues than expected • Some may be able to differentiate into a number of different cell types, given the right conditions • General consensus among scientist: • Adult stem cells DO NOT have as much potential as embryonic stem cells • CLARIFICATION: not all new adult cells arise from stem cells • Most arise by MITOSIS of differentiated cells

  15. Potential Uses for Stem Cell Research • Basic research – clarification of complex events that occur during human development & understanding molecular basis of cancer • Biotechnology(drug discovery & development) – stem cells can provide specific cell types to test new drugs

  16. Potential Uses Continued. . . . • Cell based therapies: • Regenerative therapy to treat Parkinson’s, Alzheimer’s, ALS, spinal cord injury, stroke, severe burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis • Stem cells in gene therapy • Stem cells as vehicles after they have been genetically manipulated • Stem cells in therapeutic cloning • Stem cells in cancer

  17. How Do You Make Stem Cells? • Fertilized Egg • Isolate blastocyst • Remove inner cell mass • Place into petri dish coated with feeder cells to promote division • Differentiation!

  18. Cloning • Reproductive Cloning • Producing new organisms genetically identical to donor • Therapeutic Cloning • Make a therapeutic product (vaccine, human protein etc) • Deliver organs that will not be rejected • Act as animal models for human disease • Breeding animals or plants with genetically favorable traits (genetic engineering)

  19. SCNT - Somatic Cell Nuclear Transfer 1. • Remove nucleus from egg cell and implant nucleus from patient’s cell to create fertilized egg. • Remove inner cell mass from blastocyst and place in petri dish for stem cell development & differentiation • Cells will be almost identical to patient so rejection will not occur when transplantated. 2. 3. http://www.kumc.edu/stemcell/early.htmlReprinted with permission from the University of Kansas Medical Center.

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

  21. Problems with Therapeutic Cloning (1) • Some immune rejection may occur - WHY? • About 1% of DNA in the clone will not be identical to patient • It will be identical to egg cell used in SCNT due to the mitochondrial DNA in the cytoplasm of the egg cell

  22. Problems with Therapeutic Cloning • Large number of eggs needed for SCNT which can only be obtained with: • Excessive hormone treatment of females • Surgery to remove eggs Both processes are potentially harmful to females!

  23. Tumor stem cell Tumor cell Current Efforts with SC and Cancer • Determine difference between cancer & normal stem cells • Identify potential points in pathways critical for the survival of cancer SCs • Develop therapies that specifically target cancer SC • Duke University Explanation Drawn by Christine Rodriguez

  24. Status of SC research in other countries • Great Britain • Very liberal policies on research • Therapeutic cloning allowed, use of excess embryos & creation of embryos allowed • Stem cell research allowed • France • Less liberal politics • Use of excess embryos from IVF allowed • Reproductive AND therapeutic cloning banned • Germany • Very strict policies • Use of excess embryos and creation of embryos banned • Scientists can IMPORT embryos Click here to see a map of the stem cell policy around the world!

  25. Debate in US • Federal funding available for research using the Bush lines only: • ES cell lines that were already in existence by 8/9/01 • Disadvantage of Bush stem cell lines: • May have lost regenerative ability • May have accumulated mutations or infections • Private companies continue to pursue stem cell research • Use of human embryos for IVF (in vitro fertilization) & therapeutic cloning is legal in most states • No federal funding • Some states are considering banning both

  26. Global Status • Ongoing debate regarding use of embryos • United Nations: proposal for a global policy to ban reproductive cloning only

  27. What do you think? • Click on the link to take a poll on YOUR opinion regarding using cloning for stem cell research. • Cloning for Stem Cell Research Poll

  28. Summary • Stem Cell Review Film Clip

  29. 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