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WHAT ARE STEM CELLS

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					                   WHAT ARE STEM CELLS?

 They are unspecialized cells with 2 defining properties:
1] Self renewal
2] Unlimited potency




                             STEM CELLS



               EMBRYONIC                 ADULT / SOMATIC




                     EMBRYONIC STEM CELLS

 Are the inner mass cells of the blastocyst
 Derived from embryos that develop from eggs that have been
  fertilized in vitro
 Are pluripotent ie. can become any cell type
 By directing their differentiation into specific cell types – may be able
  to treat certain disease such as Parkinson's disease, diabetes, traumatic
  spinal cord injury, Purkinje cell degeneration, Duchenne's muscular
  dystrophy, heart disease, and vision and hearing loss (Kondziolka,
  2002; Daley et al., 2003; Bethesda1, 2008)
                          ADULT STEM CELLS

  Undifferentiated cells found in adult tissues or organs
  Can replicate and differentiate to form specialized cells of a tissue or
   organ
  Found in the brain, bone marrow, peripheral blood, blood vessels,
   skeletal muscle, skin and liver (Bethesda2, 2008)
  By manipulating them into generating specific cell types – could be
   used for potential treatments such as replacing the dopamine-
   producing cells in the brains of Parkinson's patients, developing
   insulin-producing cells for type I diabetes and repairing damaged
   heart muscle following a heart attack with cardiac muscle cells (Daley
   et al., 2003; Bethesda2, 2008)



 NORMAL DIIFERENTIATION PATHWAYS OF ADULT STEM
               CELLS (Bethesda2, 2008)

  Hematopoietic stem cells – give rise to all types of blood cells
  Bone marrow stromal cells / mesenchymal stem cells – gives rise to
   bone cells, cartilage cells, fat cells and other types of connective tissue
   cells
  Neural stem cells – give rise to nerve cells and non-neuronal cells
  Epithelial stem cells – give rise to absorptive cells, goblet cells and
   enteroendocrine cells



INORDER FOR TISSUE REGENERATION TO TAKE PLACE, WE
         NEED STEM CELLS TO (Bethesda3, 2008):

    Multiply extensively and generate sufficient amounts of tissue
    Differentiate into the desired cell type
    Survive in the recipient after transplant
    Integrate into the surrounding tissue after transplant
    Function appropriately
    Not harm the recipient in any way
Bethesda1 , M.D.: National Institutes of Health, U.S. Department of Health and Human
Services. 2008. Stem cell information - Stem Cell Basics: What are embryonic stem
cells? [online]. Available: http://stemcells.nih.gov/info/basics/basics3 [accessed 25
September 2008].

Bethesda2 , M.D.: National Institutes of Health, U.S. Department of Health and Human
Services. 2008. Stem cell information - Stem Cell Basics: What are adult stem cells?
[online]. Available: http://stemcells.nih.gov/info/basics/basics4 [accessed 25 September
2008].

Bethesda3 , M.D.: National Institutes of Health, U.S. Department of Health and Human
Services. 2008. Stem cell information - Stem Cell Basics: What are the potential uses of
human stem cells and the obstacles that must be overcome before these potential uses will
be realized? [online]. Available: http://stemcells.nih.gov/info/basics/basics6 [accessed 25
September 2008].

Daley, G.Q., Goodell, M.A., Snyder, E.Y. 2003. Realistic prospects for stem cell
therapeutics. American Society of Hematology. 398-418.

Kondziolka, D., Wechsler, L., Achim, C. 2002. Neural transplantation for stroke.
Journal of Clinical Neuroscience. 9, 225-230.

				
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