About Regenerative Biology
What is Regenerative Biology?
The study of regenerative biology encompasses many distinct areas. For instance, regeneration can occur through use of any of the following mechanisms:
1) Pre-existing differentiated cells. This kind of regeneration involves either the proliferation of differentiated cells (compensatory hyperplasia) or their dedifferentiation to a progenitor state, proliferation and redifferentiation. The liver regenerates by compensatory hyperplasia and heart cells by dedifferentiation and redifferentiation.
2) Transdifferentiation. In this process, the cells transform directly from one differentiated cell type into another. The most spectacular example is the transdifferentiation of pigmented cells of the iris into lens cells after lentectomy of the newt eye.
3) Growth of cell processes. This type of regeneration takes place after crush injury or transection of peripheral nerve axons. Axons in the brain and spinal cord do not regenerate, and a major focus of regenerative medicine is to devise therapies that promote their regeneration.
4) Adult stem cells. Many tissues use adult stem cells to regenerate, such as the hematopoietic system, bone, muscle, skin epidermis, hair, intestine, and airways, but these cells are not always easy to use for tissue replacement.
5) Embryonic or induced pluripotent stem cells. now know how to create stem cells that are the equivalent of embryonic stem cells by reprogramming adult skin cells in culture. These cells are called induced pluripotent stem cells and they can be differentiated to almost any type of adult stem cell or fully differentiated derivative, a great advantage for cell and tissue replacement.
Of critical importance is that many organs typically have more than one way to regenerate, but usually don’t use all of the available mechanisms. Also of critical importance is that various species may use different mechanisms to regenerate.
Beyond Mechanisms of Regeneration…
In addition to understanding how to form stem cells that may be used to generate lost tissues, regenerative biology also encompasses all of the following:
The study of the microenvironment of injured tissue that creates a milieu that is either conducive to or inhibits the generation and/or survival of new cells.
Increasing the ability of existing cells to survive and re-grow processes lost during disease or injury. This is particularly pertinent to organs that have a high degree of connectivity between cells, such as the nervous system.
The investigation of various scaffolds that can be used to combine cells and factors to construct bioartificial tissues that can be incorporated into existing structures.
The use of organoids (a 3-D construction of a tissue in vitro) as a potential replacement of the organ or as a model system that can be used to test treatments in vitro.
The exploration of molecules and signaling pathways that are necessary for the various processes in the regenerative process, including proliferation, differentiation, and anti-inflammation.
The study of functional and morphological incorporation of newly derived cells into the existing network of cells within the organ.
Many, many more……
Want to learn more? Check the following resources.
1. Regenerative Biology and Medicine. 2nd edition (2012). David L. Stocum. Academic Press, San Diego, CA.
2. Principles of Regenerative Medicine. 2nd edition (2013) Anthony Atala, Robert Lanza, James Thomson, Robert Nerem. Academic Press, San Diego, CA
3. New Perspectives in Regeneration. (2013) Ellen Heber-Katz, David L. Stocum. Springer, New York.