Every field has it's own dialect and it can be helpful when learning about a new area to know what scientists are referring to when they discuss topics.  Some important words and their corresponding definitions will be helpful when learning about Regenerative Medicine:

• Repair (Fibrosis) is the alternative to regeneration.  Also known as fibrosis, it is the most common mechanism by which our bodies repair injuries.  Once repair mechanisms are initiated, elements of the immune system are the first to the site, eliciting a ‘quick repair’ response so as not to risk infection or more damage.  Our bodies are then triggered to lay down non-functional scar tissue and we loose the opportunity to regenerate and regain function of the injured organ.
  • Scientists are still working to uncover the how and why behind our body’s choice to regenerate certain organs (liver) vs replacing the lost organ entirely with scar tissue (lost fingers).  
  • Examples of tissues that undergo repair by the formation of scar tissue are the skin, cartilage, spinal cord, nerves, most areas of the brain, tissues in the eye, cardiac muscle, lung and kidney tissue.

• Regeneration is defined as the process of replacing injured tissue with undamaged, specialized cells that allow for the restoration of normal tissue function.  In contrast to repair, regeneration of tissue can restore interrupted connections (think repair of damaged heart tissue, bone regrowth after amputation, or repair of severed nerves after a severe accident) throughout the body by growing the missing organ from its original anatomical site.
  • Critical questions for scientists:
    •  ‘Why are some organs or tissues in our bodies capable of regenerating while others can only utilize the alternative healing mechanism, repair by fibrosis?' 
    • How can we manipulate those mechanisms to grow healthy tissue after disease or damage and how can this be applied to help patients?

• Stem Cells are unspecialized cells that have not yet “decided” what type of adult cell they will be.
  • They can self-renew and make two new stem cells
  • They can differentiate to make multiple types of cells
  • They are capable of expanding in number and they can become many different types of cells that are needed throughout the body
  
• Tissue: An orderly grouping of cellular materials that function together to carry out a specific purpose within the body.

• For example, your muscles are composed of many layers of tissue that contain thousands of smaller units called cells, the most basic functional unit of our bodies.  The cells in the tissue work together to contract and relax isolated areas of your body as you move.

• Tissue engineering: The process of creating tissues outside of the body, typically in the laboratory, intended for later use in implantation or transplants to replace damaged or diseased tissue. 

Reference: Regenerative Biology and Medicine, David L Stocum ©2006, Elsevier Inc.