Axolotl%20Limb%20Regeneration

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Axolotl Limb Regeneration

• By Jordan Sudario-Cook

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Axolotl

• The axolotl is a species of salamander that lives
  mainly in areas of Mexico.
• This species of salamander have extensive
  regenerative properties and can regenerate their
  limbs, tail, spinal cord and even parts of their
  brain.
• Researchers have been studying this animal for
  many decades trying to figure out the process in
  which these animals regenerate their limbs and
  how they could eventually replicate the process
  in humans.

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Current Research

• Right now scientists have been using two main
  procedures to study the regenerative properties
  of Axolotl limbs.
• In the primary method the scientists simply
  amputate a leg from the Axolotl.
• In the second method, scientist create a wound in
  an area of the body and cut a nerve around the
  wound and place a skin graft from an area of the
  limb onto the wound.

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Regenerative Process

• After the limb has been amputated, neurotrophic
  factors called fibroblast growth factors act on
  the wound epithelium of the area forming an
  apical epithelial cap which is a layer of
  signaling cells.
• This apical epithelial cap, along with the cut
  nerve, help to inhibit wound healing.
• While this cap is forming, fibroblasts from the
  surrounding connective tissue migrate to the
  amputated area.

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Regenerative Process(cont.)

• These fibroblasts form a blastema which is a mass
  of cells located at the amputated site that are
  capable of regeneration.
• At first these blastema were thought to contain
  undifferentiated pluripotent cells but it is now
  believed that these blastema may contain cells
  that remember the cells of the former limb. This
  means that these cells are a collection of
  restricted progenitor cells.
• Once the limb bud forms, research has shown that
  the same developmental genes (such as HoxA and
  HoxD) that were seen in the developing limb in
  the embryo are also present in this limb
  regeneration.
• Once these genes are presented, the limb reforms
  in the span of about a month to two months and is
  indistinguishable from the former limb.

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Human Regeneration

• By fully understanding this process in the
  Axolotl salamander, scientists may be able to
  replicate the process in humans.
• This process is still not fully understood and
  could still take many years to truly see how it
  works.
• The major landmark would be figuring out how to
  prevent the natural scarring that occurs in
  humans as the blastema formation seems to be the
  major factor in regenerating limbs.

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Ethical Considerations

• The issue of animal testing is a major
  consideration because these animals are being
  bred only to be experimented on.
• The Axolotl species is close to extinction.
• Giving humans the ability of other animals is
  seen by some people as going against the process
  of evolution.

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Future

• If scientists were able to replicate this in
  humans, this method could be used in amputee
  patients and maybe even in organ regeneration.
• This field could completely replace prosthetics.

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References

• http//life-sea.blogspot.com/2011/12/axolotl.html
• http//en.dogeno.us/2009/08/cells-memorize-their-t
  issue-origin-during-axolotl-limb-regeneration-the-
  blastema-is-a-heterogeneous-collection-of-restrict
  ed-progenitor-cells/
• http//onlinelibrary.wiley.com/doi/10.1002/ar.2252
  9/pdf
• downloads.hindawi.com/journals/tswj/2006/630306.pd
  f
• http//en.wikipedia.org/wiki/Axolotl
• http//www.sci-news.com/genetics/article00615.html
  
• http//www.rationalskepticism.org/biology/fluoresc
  ent-cells-tracked-in-axolotl-limb-regeneration-t22
  918.html
• http//www.wired.com/wiredscience/2009/07/regenera
  tion/
• http//www.biomedcentral.com/1741-7007/7/83