Stem cell

• Stem cells


  Undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell
• Stem cells


  • Self-renewal: The ability of a stem cell to divide and produce copies of itself for an indefinite period of time
  • Totipotent: A cell capable to form entire organism. The zygote is totipotent; not demonstrated for any vertebrate stem cell
  • Pluripotent: A cell able to form all the body's cell lineages, including germ cells, and some or even all extraembryonic cell types. Example: embryonic stem cells
  • Multipotent: A cell able form multiple mature cell types that constitute an entire tissue or tissues. Example: haematopoietic (blood) stem cells
  • Differentiation: The process by which cells become specialized to perform particular tasks
• Regenerative medicine


  Reconstruction of diseased or injured tissue by activation of resident cells or by cell transplantation
• Stem cell types


  • Embryonic stem cells
  • Adult stem cells
  • Induced pluripotent stem (iPS) cells
• Embryonic stem cells


  • Cell lines last and last and last
  • Multipotent
  • Easy to find
  • Ethical issues - when does life begin?
• Adult stem cells


  • Cell lines do not last
  • Not multipotent
  • Hard to locate
  • Minimal ethical issues
• Derivation and use of embryonic stem cells

  1. Cultured blastocyst

  2. Isolated inner cell mass

  3. Inactivated mouse embryonic fibroblast (MEF) feeder cells

  4. New MEF cells dissociated and replated

  5. Established cell culture

  6. Differentiation to airway epithelium, pancreatic β cells, intestinal cells

  7. Partially differentiated cell injected back
• What do cultured ES cells look like?

  • Fluorescent imaging of embryonic stem cell colonies
• What to do with stem cells?

  1. Isolation

  2. Characterization

  3. Expansion

  4. Differentiation
• Adult stem cells have also been discovered in multiple organs
• Stem cell reprogramming


  1. Transformed healthy somatic cells into stem cells using genetic reprogramming

  2. Yamanaka factors: By altering the genes in the adult cells, researchers can reprogram the cells to act similarly to embryonic stem cells

  3. Most common starter cells are fibroblasts, or other types of skin cells

  4. New directions to transdifferentiate: lineage reprogramming, is the process in which one mature somatic cell is transformed into another mature somatic cell without undergoing an intermediate pluripotent state or progenitor cell type
• Hematopoietic stem cell (HSC)


  It is estimated that there are approximately 10,000 HSCs, of which, in humans, approximately 1,000 contribute hematopoiesis at any given time
• Hematopoietic stem cell therapy (HCT) uses

  • Lymphomas and thymomas
  • Hematopoietic cells
  • Metastatic cancers of other origins
  • Autoimmune diseases with hematopoietic stem cells (HSCs): Rheumatoid arthritis, Systemic Lupus Erythematosus, Type 1 diabetes mellitus, Multiple sclerosis, Pernicious anemia
• Hematopoietic stem cell


  • Best-studied, used clinically for 30+ years
  • Allogeneic and Autologous stem cell transplantation
• Umbilical cord stem cells (UCS cells)


  • Also known as Wharton's Jelly, a gelatinous connective tissue contained in the umbilical cord
  • Adult stem cells of infant origin
  • Isolated prior to/ immediately following birth
  • Haematopoietic stem cells (Majority)
  • 100,000 stem cells per mL in UCB
  • Alternate to bone marrow stem cells
• Stem cells are undifferentiated, unspecialized cells that have the ability to divide through mitosis to produce more stem cells or differentiate into specialized cells.
• Embryonic stem (ES) cells can be derived from embryos at an early stage of development and have the potential to develop into any type of tissue in the body.
• Adult stem cells are found in various tissues throughout the body and can give rise to specific types of cells within those tissues.
• Tissue-specific stem cells are present in many organs and tissues and can only give rise to certain types of cells within those tissues.
• Hematopoietic stem cells (HSCs) reside in bone marrow and give rise to all blood cell lineages.
• Induced pluripotent stem (iPS) cells are created by reprogramming adult cells with specific genes to become pluripotent again.
• Tissue-specific stem cells are present in many organs and tissues and can generate new cells when needed.
• Adult stem cells are found in various tissues throughout the body and have the potential to regenerate damaged tissue but cannot differentiate into all types of cells like ES cells.
• Umbilical cord stem cells (UCS cells)


  Alternate source of stem cells
• Wharton's Jelly


  Gelatinous connective tissue contained in the umbilical cord
• Adult stem cells of infant origin

  Isolated prior to/ immediately following birth
• Haematopoietic stem cells


  Majority of stem cells in UCB, 100,000 per mL
• Haematopoietic stem cells


  Alternate to bone marrow stem cells
• Differentiation


  The ability of the stem cell to develop into many different types of cells in the body
• Self-Renewal


  The ability of the stem cell to self-regenerate many times, contributing to the stock of stem cells in the body
• The Healing Process


  1. Injury

  2. Inflammatory

  3. Proliferation

  4. Remodeling
• Stem Cell Therapies


  • Alzheimer's
  • Blindness
  • Cancer
  • Diabetes
  • Heart Attack
  • Vascular Grafts
• Tissue Engineering


  To assemble functional constructs that restore, maintain, or improve damaged tissues or whole organs
• Regenerative Medicine


  Process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function
• Applications of Stem Cell Therapies

  Therapeutic or Diagnostic
• The Vacanti Mouse was a landmark study from 1997 that helped launch the field of tissue engineering
• Tissue engineering is a multidisciplinary field that applies the principles of engineering and life sciences towards the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ
• Disciplines involved in Tissue Engineering

  • Medical doctors
  • Biologists
  • Chemists
  • Engineers
• Biomaterials


  A material intended to interact with biological systems to evaluate, treat, augment or replace and tissue, organ or function in the body
• Strategies for optimized natural biomaterials

  • Higher production and lower costs
  • Regulation of material properties
  • Better biosafety
  • Design of unknown biomaterials
  • Optimized manufacturing of biomaterial devices