By Jordan Sudario-Cook
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.
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.
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.
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.
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.
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.
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.
References
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http://life-sea.blogspot.com/2011/12/axolotl.html
http://en.dogeno.us/2009/08/cells-memorize-their-tissue-origin-during-axolotl-limb-regenerationthe-blastema-is-a-heterogeneous-collection-of-restricted-progenitor-cells/
http://onlinelibrary.wiley.com/doi/10.1002/ar.22529/pdf
downloads.hindawi.com/journals/tswj/2006/630306.pdf
http://en.wikipedia.org/wiki/Axolotl
http://www.sci-news.com/genetics/article00615.html
http://www.rationalskepticism.org/biology/fluorescent-cells-tracked-in-axolotl-limb-regenerationt22918.html
http://www.wired.com/wiredscience/2009/07/regeneration/
http://www.biomedcentral.com/1741-7007/7/83