Properties and uses of stem cells

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A stem cell is a "blank" cell that can give rise to multiple tissue types such as a skin, muscle, or nerve cell.
Under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions.

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Properties and uses of stem cells

  1. 1. PROPERTIES AND USES OF STEM CELLS Presented by Dr.B.Victor., Ph.D., Email:bonfiliusvictor@gmail.com, Blog:bonvictor.blogspot.com.
  2. 2. Presentation outline         Stem cell explanation, properties Classes of stem cells Embryonic stem cells (ESC) Adult Stem cells (ASC) Cord blood stem cells Cord blood banks Stem cell therapy Summary
  3. 3. General properties of Stem Cells
  4. 4. Unique features of stem cells
  5. 5. Three unique properties of stem cells
  6. 6. Stem cells are unspecialized
  7. 7. Stem cells are capable of dividing and renewing themselves for long periods.
  8. 8. Stem cells can give rise to specialized cells     Differentiation is the process of becoming specialized stem cells from unspecialized cells. The signals inside and outside cells that trigger stem cell differentiation. The internal signals are controlled by a cell's genes. The external signals include chemicals secreted by other cells, physical contact with neighboring cells in the microenvironment
  9. 9. Stem cells exist in both embryos and adults
  10. 10. COMPARISON OF PROGENITOR/PRECURSOR CELLS AND STEM CELLS.
  11. 11. Distinguishing Features of Progenitor Cells and Stem Cells. Stem cells    A stem cell is an unspecialized cell that develops into a variety of specialized cell types. a stem cell divides and gives rise to one additional stem cell and a specialized cell. Example: a hematopoietic stem cell produce a second generation stem cell and a neuron. A progenitor cell   A progenitor cell is unspecialized that is capable of undergoing cell division and yielding two specialized cells. Example: a myeloid progenitor cell undergoing cell division to yield two specialized cells (a neutrophil and a red blood cell).
  12. 12. Sources of stem cells.
  13. 13. Embryonic stem cells
  14. 14. Sources of embryonic stem cells * Embryos - Embryonic stem cells are obtained from 5-7 days old living embryos. The removal of embryonic stem cells results in the destruction of the embryo. * Fetuses - Embryonic germ cell, can be obtained from either miscarriages or aborted fetuses.
  15. 15. Adult stem cells
  16. 16. Sources of adult stem cells Adult stem cells can be derived from Umbilical Cords, Placentas and Amniotic Fluid.  Adult stem cells are present within the bone marrow, liver, epidermis, retina, skeletal muscle, intestine, brain, dental pulp and elsewhere. 
  17. 17. Advantages of Embryonic Stem Cells 1. Flexible - have the potential to make any cell. 2. Immortal –can provide an endless supply of cells. 3. Availability - embryos from in vitro fertilization clinics.
  18. 18. Disadvantages of Embryonic Stem Cells 1. 2. 3. 4. Difficult to differentiate uniformly into a target tissue. Immunogenic - cells from a random embryo donor may be rejected after transplantation Tumorigenic - capable of forming tumors. Destruction of developing human life.
  19. 19. Advantages of Adult Stem Cells 1. 2. 3. 4. 5. 6. Adult stem cells from bone marrow and umbilical cords appear to be as flexible. Somewhat specialized. Not immunogenic - recipients who receive the products of their own stem cells will not experience immune rejection. Relative ease of procurement - some adult stem cells are easy to harvest (skin, muscle, marrow, fat) Non-tumorigenic-tend not to form tumors. No harm done to the donor.
  20. 20. Disadvantages of Adult stem cell 1. Limited quantity - can sometimes be difficult to obtain in large numbers. 2. Finite - may not live as long as embryonic stem cells in culture. 3. Less flexible - may be more difficult to reprogram to form other tissue types
  21. 21. Why are adult stem cells preferable to embryonic stem cells?     Adult stem cells are naturally exist in our bodies, and they provide a natural repair mechanism for many tissues. They belong in the microenvironment of an adult body, where they never cause tumors and immune system reactions. Adult stem cells have already been successfully used in human therapies for many years. NO THERAPIES in humans have ever been successfully carried out using embryonic stem cells.
  22. 22. Superior features of ESCs Embryonic stem cells are easier to identify, isolate and harvest.  They grow more quickly and easily in the lab than adult stem cells.  They can be more easily manipulated (they are more plastic) 
  23. 23. Classification of stem cells Stem cells can be classified by the extent to which they can differentiate into various cell types. totipotent, pluripotent, multipotent, unipotent stem cells
  24. 24. Totipotent stem cells 1. 2. 3. The fertilized egg is said to be totipotent from the Latin totus, meaning “entire”. The very first cells of an embryo, being the 'stem' of all future cells of the organism. It has the potential to generate all the cells and tissues that make up an embryo.
  25. 25. Pluripotent stem cells Pluripotent stem cells are descendants of the totipotent stem cells of the embryo. These cells, which develop about four days after fertilization, can differentiate into any cell type, except for totipotent stem cells and the cells of the placenta.
  26. 26. Pluripotent stem cells The term pluripotent is used to denote the cells derived from all three embryonic germ layers mesoderm, endoderm, and ectoderm. Pluripotent cells have the potential to give rise to any type of specialized cell of the human body. “Pluri” is derived from the Latin plures means several or many.
  27. 27. Multipotent stem cells Multipotent stem cells are descendents of pluripotent stem cells. For example, hematopoietic stem cells, which are found primarily in the bone marrow, give rise to all of the cells found in the blood, including red blood cells, white blood cells, and platelets.
  28. 28. Unipotent stem cell Unipotent stem cell, a term that is usually applied to a cell in adult organisms differentiating along only one lineage. "Uni" is derived from the Latin word unus, which means one. The adult stem cells in many differentiated tissues are typically unipotent.
  29. 29. Progenitor cells Progenitor cells (or unipotent stem cells) can produce only one cell type. For example, erythroid progenitor cells differentiate into only red blood cells.
  30. 30. Blood is made in the Bone MarrowBlood Cell Development
  31. 31. “Terminally differentiated" cells At the end of the long chain of cell divisions are "terminally differentiated" cells, such as a liver cell or lung cell, which are permanently committed to specific functions.
  32. 32. Adult stem cells The adult stem cell is an undifferentiated (unspecialized) cell that is found in a differentiated (specialized) tissue; it become specialized to yield all of the specialized cell types of the tissue from which it originated. Adult stem cells are capable of selfrenewal for the lifetime of the organism.
  33. 33. Sources of Adult stem cells
  34. 34. Adult stem cells(ASC) or somatic stem cells Adult stem cells are undifferentiated cells. They are found in small numbers in most adult tissues. They can also be extracted from umbilical cord blood. They are also called “somatic stem cells,” They are multipotent in nature. E.g. hematopoietic stem cells, which form all the various cells in the blood.
  35. 35. Plasticity of Adult stem cells   Stem cells from one tissue may be able to give rise to cell types of a completely different tissue, a phenomenon known as plasticity . Examples of such plasticity include blood cells becoming neurons, liver cells that can be made to produce insulin, and hematopoietic stem cells that can develop into heart muscle.
  36. 36. Plasticity of adult stem cells
  37. 37. Hematopoietic stem cells (HSC)    Blood cells are formed from hematopoietic stem cells (HSC) by a process known as hematopoiesis HSCs are first formed in the embryonic yolk sac, then migrate to the fetal liver and spleen. Bone marrow becomes the major location of HSC and continues this role throughout life  HSC properties  HSC are pluripotent - they can differentiate into a number of different blood cell types, including lymphocytes, granulocytes, monocytes, mast cells, megakaryocytes, and erythrocytes HSC are self-renewing - they can divide to replenish themselves in their pluripotent (undifferentiated) state. 
  38. 38. Umbilical cord stem cells Blood from the placenta and umbilical cord that are left over after birth is a rich source of hematopoietic stem cells. These so-called umbilical cord stem cells have been shown to be able to differentiate into bone cells and neurons, as well as the cells lining the inside of blood vessels.
  39. 39. Cord blood stem cells The umbilical cord and placenta are rich sources of stem cells. Cord blood collection is a safe, simple procedure that poses no risk to the mother or newborn baby.
  40. 40. Cord blood stem cells Cord blood stem cells can grow into blood forming cells, immune system cells or other types of cells. Cord blood stem cells have been used to treat 70 different diseases, including leukemia, lymphoma, and inherited diseases.
  41. 41. Cord- blood banking  Cord blood banks collect and store the blood within the umbilical cord and placenta after the birth of a baby.  The stem cells are separated from the rest of the blood and stored frozen in liquid nitrogen.  There are 2 types of banks i.e. public and family cord blood banks.
  42. 42. Embryonic Stem Cells(ESC)    Embryonic Stem Cells are derived from embryos that develop from eggs that have been fertilized in vitro. Embryonic Stem Cells are never derived from eggs fertilized inside of a woman's body. Human Embryonic Stem Cells are derived are typically four or five days old embryos.
  43. 43. Properties of Embryonic Stem Cells     Derived from the inner cell mass of the blastocyst. Capable of undergoing an unlimited number of symmetrical divisions without differentiating (longterm self-renewal). Exhibit full (diploid), normal complement of chromosomes. Pluripotent ES cells can give rise to differentiated cell types that are derived from all three primary germ layers of the embryo (endoderm, mesoderm, and ectoderm).
  44. 44. Potential sources of Human stem cells (HSC) Aborted fetal tissue excess embryos from fertility clinics embryos created through in vitro fertilization Asexually created embryos by a human somatic cell nucleus transfer to an egg with its own nucleus removed. Other sources include umbilical cord blood and bone marrow.
  45. 45. Stem cell therapy. Numerous diseases and damaged organs could potentially be treated with cell therapy. Treatment of neural diseases such as Parkinson's disease, Huntington’s disease and Alzheimer's disease. Repair or replace damaged neurons. Repair of damaged organs such as the liver and pancreas. Treatments for AIDS.
  46. 46. Stem cell transplantation (SCT)/ Bone marrow transplantation (BMT).    When a patient's bone marrow fails to produce new blood cells, for whatever reason, he or she will develop anemia, persistent infections and bleeding problems. In order to restore blood cell production a patient may be given Stem cell transplantation (SCT) for healthy stem cells. Stem cell transplants are used to treat malignant diseases, mainly leukemia, lymphoma or myeloma which involve the bone marrow.
  47. 47. Cancer treatment Intense chemotherapy damages a person’s bone marrow. A chemo-cancer patient is left vulnerable to infection, anemia and bleeding because of the depletion of fresh blood cells. Transplanting bone marrow tissue into a chemo-cancer patient may be carried out.
  48. 48. Skin tissue repair   skin, is readily cultured to provide replacement tissue for burns victims. Healthy skin cells from the patient can be grown rapidly in vitro to provide selfcompatible skin grafts.
  49. 49. Myocardial Regeneration     Cardio-myocytes lose their ability to proliferate after birth and so heart muscle fibers cannot regenerate. Myocardial injury, such as myocardial infarction (MI), heals by replacement of contractile heart muscle fibers by fibrotic tissue scar, which not only cannot participate in pumping of blood. The implanted myoblastic cells have the ability to restore function of damaged cardio- myocytes. It is possible to treat patients with extensive myocardial infarction by cell transplantation (CT).
  50. 50. Is Stem Cell Research Ethical? Embryonic Stem Cells - morally objectionable, because the human embryo must be destroyed during harvest. Embryonic Germ Cells - morally objectionable when utilizing fetal tissue derived from elective abortions. Umbilical Cord Stem Cells - morally acceptable, since the umbilical cord is no longer required once the delivery has been completed. Placentally-derived Stem Cells - morally acceptable, since the afterbirth is no longer required after the delivery has been completed. Adult Stem Cells - morally acceptable.
  51. 51. Summary      The stem cells inside an embryo will eventually give rise to every cell, organ and tissue in the fetus's body. Stem cells are unspecialized cells Stem cells can divide and renew themselves for long periods of time Stem cells can divide and become specific specialized cell types of the body Stem cells can replace dying, old or damaged cells.
  52. 52. References      Odorico, J.S., Kaufman, D.S., and Thomson, J.A. (2001). Multilineage differentiation from human embryonic stem cell lines. Stem Cells. 19, 193 -204. Smith, A.G. (2001). Origins and properties of mouse embryonic stem cells. Annu. Rev. Cell. Dev. Biol. Thomson, J.A. and Marshall, V.S. (1998). Primate embryonic stem cells. Curr. Top. Dev. Biol. 38, 133165. Chandross, K.J. and Mezey, E. (2001). Plasticity of adult bone marrow stem cells. Mattson, M.P. and Van Zant, G. eds. (Greenwich, CT: JAI Press). Slack, J.M. (2000). Stem cells in epithelial tissues. Science. 287, 1431-1433.
  53. 53. References     Dzierzak, E., Medvinsky, A., and de Bruijn, M. (1998). Qualitative and quantitative aspects of haematopoietic cell development in the mammalian embryo. Immunol. Today. 19, 228-236. MacKey, M.C. (2001). Cell kinetic status of haematopoietic stem cells. Cell. Prolif. 34, 71-83. J. A. Thomson, et al., 'Embryonic stem cell lines derived from human blastocysts', Science, no. 5391, vol. 282, November 1998, pp. 1145–7. B. E. Reubinoff, M. F. Pera, C-Y Fong, A. Trounson and A. Bongso, 'Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro', Nature Biotechnology, vol. 18, pp. 399–404, 01 April 2000.
  54. 54. About the presenter      Dr. B. Victor is a highly experienced postgraduate professor, retired from the reputed educational institution St. Xavier’ s College(Autonomous), Palayamkottai, India627001. He was the dean of sciences, assistant controller of examinations and coordinator several academic research workshops. He has more than 32 years of teaching and research experience He has taught a diversity of courses and published 45 research articles in reputed national and international journals. Send your comments to : bonfiliusvictor@gmail.com
  55. 55. THANK YOU FOR WATCHING

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