Tissue Engineering Higby - Lecture 1

  1. What is tissue engineering
    • Any interdisciplinary field that applies the principles of engineering and life sciences for the development of therapeutic strategies aimed at the:
    • Replacement
    • Repair
    • Maintenance
    • Enhancement of tissue function for clinical use

    Other uses include drug testing and toxicity. In vitro models and test systems are also important for future human uses.
  2. From a ___ to a tissue, to a ____, to a system.

    This is then used to replace any damaged or diseased part.
    From a cell to a tissue, to a organ, to a system.
  3. What does the mantra "form follows function" mean?
    "Form follows function" refers to the observations that systems are shaped in a manner to maximize their function.

    For instance, the aveoli sacs within the lungs require high surface areas to keep the efficiency of the Oxygen/Cabon dioxide exchange as high as possible.
  4. What are some of the potential gains of tissue engineering?
    • Cell based therapeutics (drug delivery)
    • In vitro tissue systems (toxicity/pharmacokinetics or disease mechanisms)
    • Gene delivery systems
    • Organ replacement
    • Functional organ support
    • Improved healing
    • Tissue regeneration
    • Limb re-growth
    • Replace of missing parts and functionality
  5. What are the Three essentials for tissue engineering and their associated functions?
    • Cells - building blocks
    • Extracellular matrix - holds cells together (structure that may use scaffolds)
    • Organization - architecture
  6. What is another approach towards replacing damaged tissue besides tissue engineering? What does it consist of?
    Developmental biology's approach towards the replacement of damaged tissues involves the use of stem cells to repopulate damaged tissue or transplant of cells from a donor to a recipient.

    • Stem cells to repopulate damaged tissue
    • ECM to attract marrow stem cells
    • Prepare an artificial matrix that contains
    • differentiation factors
    • stem cells
    • directions for the architecture

    The stem cells would expand in vivo to take on normal structure and function as directed by the local environment.
  7. What does the Tissue engineering approach consist of? Where does the expansion of cells occur?
    • It follows that stem cells and mature cells are harvested
    • expanded in vitro (compared to in vivo)
    • seeded on the scaffold
    • forms the mature construct
    • vascularize construct
    • implant in paptient
    • control immunogenicity
    • return to function

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  8. What would be the approach for improving the function of the pancreas (endocrine system that is involved in signaling the body to absorb glucose from the blood stream)?
    The pancreas consists of several components including the signaling of tissues to absorb glucose from the blood stream and the release of glucose from the tissues.

    It includes Beta cells and Alpha cells.

    The scaffold would have to be constructed from a biocompatible material with the proper signaling proteins and chemicals, such as ligands and fibronectin.
  9. What are some of the cardiac vavlular issues?
    • Leaky valves
    • Increased cardiac demand
    • Cardiac hypertrophy
    • Hypertension
    • Fibrotic valves
    • Inconsistent with life
  10. What are the three sources of cells?
    • Autologous cells - From same organism
    • Allogeneic cells - From others of the same species
    • Xenogeneic cells - From another species
  11. What are Mesenchymal stem cells (MSC)?
    Multipotent stem cells or stem cells that give rise to a limited number of lineages.

    These cells can differentiate into a variety of cells including osteoblasts (bone cells), chrondocytes (cartilage), adipocytes (fat cells).
  12. What are Hematopoietic stem cells (HSC)?
    Multipotent stem cells or stem cells that give rise to a limited number of lineages.

    These cells can differentiate into all the different types of blood cells.
  13. What are somatic stem cells?
    Multipotent stem cells or stem cells that give rise to a limited number of lineages.

    Undifferentiated cells, found throughout the body after embryonic development, that multiply by cell division to replenish dying cells and regenerate damaged tissues.
  14. What are embryonic stem cells (ESC)?
    • Pluripotent stem cells or stem cells that have the potential to differentiate into any of the three germ layers:
    • endoderm, mesoderm, ectoderm

    These cells are found in the inner cell mass of the blastocyst of the embryo.
  15. What are the three classications of stem cells and their description?
    • Totipoent stem cells -
    • Multipotent stem cells -
    • Pluripotent stem cells -
  16. How do stem cells different from other cells in the body?
    All stem cells - regardless of their source - have three general properties:

    • They are capable of dividing and renewing themselves for long periods
    • They are unspecialized
    • They can give rise to specialized cell types
  17. What is a scaffold?
    Primary role: Provide a temporary substrate to which transplanted cells can adhere for cell adhesion, proliferation, differentiation and migration while allowing for cell communication.

    Most synthetic polymer scaffolds do not possess the specific signals (ligands) that can be recognized by cell-surface receptors. It is preferable that the polymer chain have chemically modified functional groups or the ligand may be immobilized on the scaffold surface.

    Most organ cell types are anchorage-dependent and require the presence of a suitable substrate in order to survive and retain their ability to proliferate, migrate, and differentiate.
  18. What are the various variations in scaffold designs?
    There are several variations that are possible that are all interconnected:

    • Material variations (material selection)
    • Structural variations (mechanical properties and requirements such as porosity, pore size, and pore structure to create a scaffold with similar mechanical properties to the tissue or organ)
    • Fabrication variation (various methods are available for the fabrication of tissue scaffolds)
  19. What is a bioreactor?
    An open, semi-open, semi-closed, or closed environment that promotes the survival of a limited and specified population of cells that may be outside of their usual environment, location, or physiology.

    The bioreaction perofrms a metabolic task, facilitates a particular synthesis, and/or promotes (normal of some kind of) growth, differentiation, and function with dramatic reduction in the number of variables affecting the process.
  20. What is the typical path from undifferentiated cells to implant for tissue engineering?
    • Unidifferentiated cells
    • Differentiation cues
    • Defined cell types
    • Into recipient - takes function, no immune compromise, no cancer
  21. What is the blastema?
    A mass of undifferentiated cells that will re-develop lost organ or tissue.
  22. (T/F) On the lecture slide it stated:
    Nearly every disease/condition/ailment has an animal model. If it doesn't, we can create one.
  23. What are some of the ethical aspect of care and use of animals in research?
    • Proper handling of animals and drug administration techniques
    • Anesthetizing and ventilating animals
    • Surgical procedures on small and large animals
    • Post-operative pain control
    • Use of imaging techniques with experimental animals
  24. What are the three R's for tissue engineering?
    • Refine
    • Reduce
    • Replace
Card Set
Tissue Engineering Higby - Lecture 1
Tissue Engineering Higby - General Principles, Clinical Applications, Animal Models