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Stem Cells

Stem Cells. What is a Stem Cell?. General. Specific. Unspecialized cells Give rise to more than 250 specialized cells in the body Serve as the body’s repair system. Self-Renewal Differentiation (specialization). http://www.nih.gov/news/stemcell/figure5.jpg. Two “types” of stem cells.

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Stem Cells

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  1. Stem Cells

  2. What is a Stem Cell? General Specific • Unspecialized cells • Give rise to more than 250 specialized cells in the body • Serve as the body’s repair system • Self-Renewal • Differentiation (specialization)

  3. http://www.nih.gov/news/stemcell/figure5.jpg

  4. Two “types” of stem cells • Embryonic (ES) • Adult (non-embryonic) (AS)

  5. Stem Cells differ by • Origin • Embryonic • Adult • Different “potentials” • Totipotent • Pluripotent • Multipotent Origin determines potential

  6. Potentials Totipotent - having unlimited capability. Totipotent cells have the capacity to specialize into extraembryonic membranes and all cells of the embryo. Pluripotent -capable of giving rise to most tissues of an organism. Multipotent -capable of giving rise to many tissues of an organism.

  7. Definitions • Stem cells – undifferentiated cells that have the ability to: • divide for indefinite periods in culture • to become specialized cells • Differentiation – • the process whereby cells become specialized • Produces stems cells with decreasing potential

  8. Derivation

  9. Embryonic Stem Cells (ESC) • Embryos are the result of In Vitro Fertilization (IVF) • Cells are taken from the Inner Cell Mass (ICM) of a blastocyst • ICM cells are nourished in a petri dish in an incubator • Cells are given different types of Factors/chemicals These cells can give rise to most types of cells

  10. In Vitro Fertilization (IVF) • Eggs are removed from ovary of female • Sperm is obtained from male • Egg and sperm are combined in test tubes/Petri dish • Fertilized eggs (zygotes) are allowed to divide for a few days. • Blastocysts are then transferred to uterus of woman What happens to left over embryos? • Frozen until used again • Discarded*

  11. In Vitro Fertilization + Fertilization

  12. The zygote divides Each cell is totipotent

  13. Blastocyst formation The 1st sign of differentiation Blastocyst

  14. Inner Cell Mass (ICM) Trophoblast Blastocyst Gives rise to an embryo under proper conditions These are now Pluripotent stem cells

  15. Embryonic Stem Cells

  16. Cell differentiation Can divide Can divide Differentiation Differentiation Can divide Differentiation Differentiation Pluripotent stem cell (Embryonic stem cell) Multipotent stem cells (Adult stem cell) Differentiated cells (muscle, nerve, skin, fibroblast, etc)

  17. Adult Stem Cells • Adult tissues reported to contain stem cells include: brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin and liver. • There are a very small number of stem cells in each tissue

  18. Why is research on embryonic stem cells important?

  19. Current Issues • Derivation • Induced-pluripotent stem cells • Ethics • Challenges • Controlling specialization • Donor acceptance

  20. Importance of Stem Cells • Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies. http://stemcells.nih.gov/index.asp

  21. Importance of Stem Cells • Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply.

  22. Importance of Stem Cells • Parkinson’s Disease • Loss of dopaminergic producing nerve cell in substantia nigra • Severe motor disturbance • Fetal brain cells and iPS (reprogramming) • http://www.youtube.com/watch?v=1yCgLythe00

  23. Importance of Stem Cells Alzheimers Disease • Dementia • Death brain tissue, protein placques, hippocampus • http://www.youtube.com/watch?v=zgvm_vvqq3I&feature=related • http://www.youtube.com/watch?v=TZA3QFliteA&feature=related 24

  24. Importance of Stem Cells http://www.youtube.com/watch?v=vwCrxomPbtY http://www.youtube.com/watch?v=ADchGO-0kGo&feature=related 25

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