Clip 1: Hip dysplasia Clip 2: Vet-Stem s Dr. Harman

Transcription

1 Stem Cells

2 Many breeds of large dogs are affected by hip dysplasia. This degenerative disease affects their hind legs, hindering mobility. Watch as scientists at Vet-Stem explain how stem cells are used as a cure for these animals. Clip 1: Hip dysplasia Clip 2: Vet-Stem s Dr. Harman

3 The video clip of the German Shepherd raises many questions. Imagine if Dr. Bob Harman, the lead scientist at Vet Stem, were to come to class for a discussion. What kind of questions would you ask him? What is a stem cell? Can this be done in humans? What other questions do you have?

4 What are stem cells? Stem cells can indefinitely divide and give rise to a variety of other cell types. One example is the hematopoietic stem cell which gives rise to all blood cells in the body.

5 Two types of stem cells Embryonic stem cells are pluripotentand can give rise to all types of cells in the body Adult stem cells are only multipotent and are more limited in the types of cells that they can give rise to.

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7 Totipotency the ability to produce any type of cell. Ex: zygote (embryo + placenta) Pluripotency the ability to produce any cell lineage. Ex: can differentiate into germ layers Multipotency-the ability to produce any kind of cell within a cell lineage. Ex: blood stem cell Unipotency-the ability to produce only one kind of cell. Ex: hepatocytes (liver cells)

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9 /Embryo%20Morula.jpg

10 Differentiation Events Embryonic stem cells enter the first differentiation event at the 8 cell morula stage. Each of these totipotentcells express two genes Cdx2 and Oct 3/4. At the morulastage the innermost cells no longer express the Cdx2 gene. This loss of gene expression due to position is the differentiation event.

11 _blastocyst_cred226.jpg

12 As these pluripotent cells divide they continue to be affected by their changing position. This changing position and resulting change in environment will result in other differentiation events. Three stem cell lines Differentiation

13 Three Germ Layers (three stem cell lines) As gastrulationoccurs, three layers of pluripotentstem cells are created. Ectoderm-gives rise to skin and nervous system Mesoderm-gives rise to blood, bone, and muscle Endoderm-gives rise to gut and lungs ne/snc1d/vejvoda/biology/humanconception5.jpg

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15 astrulation.gif

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17 Differentiation con t As cells differentiate, they lose some of their ability to become all types of cells. These multipotent stem cells form the three germ layers during gastrulation.

18 Mesenchymal stem cells

19 The stem cell blog

20 Skin derived precursor cells. (photo courtesy Freda Miller)

21 A stem cell emerging from rat bone marrow. By stimulating the release of stem cells after a heart attack, the healing process could be accelerated. Photograph: Imperial College London

22 Stem Cell: Paul Leonard/Photo Researchers

23 Unipotent Cells As multipotent cells divide creating either new stem cells or a specialized (unipotent) cell. These specialized cells have a variety of characteristics that suit their role in the body.

24 hite_blood_cells.jpg A scanning electron microscope image of normal human blood. Photo by Bruce Wetzel, courtesy of the National Cancer Institute

25 Scanning electron microscope image of a mammal's lung. Image by Dartmouth Electron Microscope Facility

26 ntenna/musclemachines/images/cells. jpg Dennis Kunkel Research by Stelios Andreadis has produced this smooth muscle progenitor cell derived from a hair follicle, which expresses calponin (in red), a marker for smooth muscle cells. The cell nucleus is shown in blue. (Credit: Image courtesy of University at Buffalo) Science Daily.com)

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28 Liver Cells:

29 Brain Cells:

30 Nerve Cell:

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32 Stem Cell Mysteries There are several questions that need to be answered through stem cells research How can stem cells remain unspecialized and self renewing for many years? What are the signals that cause stem cells to become specialized cells? Can we make multipotentstem cells revert to pluripotency?

33 Curing Diseases How can stem cells help to cure disease? Consider the video clip you watched at the beginning of the presentation, now imagine someone whose knee has degenerated. Explain how stem cells could be used as a cure.

34 Cancer Stem Cell: du/news/story/uploadedimag es/cancer%20stem%20celluc LA3.jpg

35 Curing Injuries Spinal Cord Injuries There are currently between 250, ,000 Americans living with a spinal cord injury. More than 13,000 additional people are injured each year. Every 41 minutes another person sustains a spinal cord injury More than half of those injured are between the ages of

36 Watch the following clips predict how these advances in stem cell therapy could help with human spinal cord injuries Paralyzed Rat walks again with Embryonic Stem Cells.AVI Paralyzed rat walks with own stem cells in 11 wks..avi

37 Sickle Cell Anemia This disease is incurable currently. The sickle cells live only days and the bone marrow cannot produce enough red blood cells to keep up resulting in anemia. An abnormality in the hemoglobin inside of the red blood cell causes this shape.