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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/10 06:22:15」(JST)

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Epimorphosis is the regeneration of tissues or organs through the dedifferentiation of existing, differentiated adult tissues.^[1] Adult cells dedifferentiate (though not fully into embryonic stem cells) into a mass of cells that then re-differentiates into the new structure. This phenomenon is seen in frog, newt, and salamander limbs. Their limbs may be amputated, but the lost portions of the limb are able to grow back.

Epimorphosis in salamander limbs

Immediately after the limb is amputated, a plasma clot forms over the wound. The epidermal cells form around the wound then grow to cover the wound in 6–12 hours; this is called the wound epidermis.^[1] No scar tissue forms, as it would in mammals.

An apical ectodermal cap (AEC) forms on the tip of the stump. This is similar to the embryonic apical ectodermal ridge, which forms during normal limb development. The AEC causes the progress zone to re-establish; this means the cells under the AEC dedifferentiate and become mesenchymal. The AEC releases factors that drives the development of the new limb. It is basically resetting the limb back to its embryonic development stage.

But even though some of the limb cells are able to dedifferentiate, they are not able to fully dedifferentiate to the level of multipotent progenitor cells. During regeneration, only cartilage cells can form new cartilage tissue, only muscle cells can form new muscle tissue, and so on. The dedifferentiated cells still retain their original specification.^[1]

References

^ ^a ^b ^c Scott F. Gilbert, Developmental Biology Tenth Edition. Sinauer Associates, Inc. Sunderland, MA, USA, 2014. pp 571-573

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English Journal

Regeneration versus scarring in vertebrate appendages and heart.

Jaźwińska A1, Sallin P1.
The Journal of pathology.J Pathol.2016 Jan;238(2):233-46. doi: 10.1002/path.4644. Epub 2015 Oct 27.
Injuries to complex human organs, such as the limbs and the heart, result in pathological conditions, for which we often lack adequate treatments. While modern regenerative approaches are based on the transplantation of stem cell-derived cells, natural regeneration in lower vertebrates, such as zebr
PMID 26414617

Regeneration of Zebrafish CNS: Adult Neurogenesis.

Ghosh S1, Hui SP1.
Neural plasticity.Neural Plast.2016;2016:5815439. doi: 10.1155/2016/5815439. Epub 2016 Jun 13.
Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibia
PMID 27382491

A Stable Thoracic Hox Code and Epimorphosis Characterize Posterior Regeneration in Capitella teleta.

de Jong DM1, Seaver EC1.
PloS one.PLoS One.2016 Feb 19;11(2):e0149724. doi: 10.1371/journal.pone.0149724. eCollection 2016.
Regeneration, the ability to replace lost tissues and body parts following traumatic injury, occurs widely throughout the animal tree of life. Regeneration occurs either by remodeling of pre-existing tissues, through addition of new cells by cell division, or a combination of both. We describe a sta
PMID 26894631