Epimorphosis

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For the mathematical function, see Epimorphism.

Epimorphosis is defined as the regeneration of a specific part of an organism in a way that involves extensive cell proliferation of somatic stem cells,[1] dedifferentiation, and reformation,[2] as well as blastema formation.[3] Epimorphosis can be considered a simple model for development, though it only occurs in tissues surrounding the site of injury rather than occurring system-wide.[4] Epimorphosis restores the anatomy of the organism and the original polarity that existed before the destruction of the tissue and/or a structure of the organism.[4] Epimorphosis regeneration can be observed in both vertebrates and invertebrates such as the common examples: salamanders, annelids, and planarians.[5]

History

Thomas Hunt Morgan, an evolutionary biologist who also worked with embryology, argued that limb and tissue reformation bore many similarities to embryonic development.[6] Building off of the work of German embryologist Wilhelm Roux, who suggested regeneration was two cooperative but distinct pathways instead of one, Morgan named the two parts of the regenerative process epimorphosis and morphallaxis. Specifically, Morgan wanted epimorphosis to specify the process of entirely new tissues being regrown from an amputation or similar injury, with morphallaxis being coined to describe regeneration that did not use cell proliferation, such as in hydra.[7] The key difference between the two forms of regeneration is that epimorphosis involves cellular proliferation and blastema formation, whereas morphallaxis does not.[7]

In vertebrates

The apical ectodermal ridge in embryonic development is very similar to the apical ectodermal cap in limb regeneration. The progress zone can be seen near to the zone of polarizing activity, which instructs cells on how to orient the limb.[8]


In vertebrates, epimorphosis relies on blastema formation to proliferate cells into the new tissue. Through studies involving zebrafish fins, the toetips of mice, and limb regeneration in axolotls, researchers at the Polish Academy of Sciences found evidence for epimorphosis occurring in a variety of vertebrates, including instances of mammal epimorphosis.[9]

Limb regeneration

Limb regeneration occurs when a part of an organism is destroyed, and the organism must reform that structure. The general steps for limb regeneration are as follows: epidermis covers the wound which is called the wound healing process,[10] the mesenchyme dedifferentiates into a blastema and a apical ectodermal cap forms, and the limb re-differentiates to form the full limb.[11]

Processes in salamanders

Epidermal cells at the wound margins migrate to cover the wound and will become the wound epidermis.

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.[12] To begin the physical formation of a new limb, regeneration occurs in a distal to proximal sequence.[17] The distal part of the limb is established first, and then the distal part of the limb interacts with the original proximal part of the limb to form the intermediate portion of the limb known as intercalation.[17]

In invertebrates

Periplaneta americana

The

paracrine system to work with muscle reformation.[18]

Capitella teleta

C. teleta is a segmented worm found in North America that is capable of regenerating posterior segments after amputation.[19] This regeneration uses the interaction of several sets of Hox genes, as well as blastema formation. All of the Hox genes concerned in epimorphosis are present in the abdominal area of the worm, but not in the anterior portion. However, the genes do not, themselves, direct the anterior-posterior patterning of the worm's thorax.[20]

Planaria vitta

totipotent stems cells[23] which allows rhabdites to secrete materials to make a protective mucosal covering and epithelium to gather at the site through spreading of the cells rather than proliferation that occurs in vertebrates[22] The dorsal and ventral epithelial cells then come to the site and become differentiated to begin regeneration.[24] The polarity of the planaria can be reestablished through an anterior-posterior gradient through Wnt/β-catenin signaling pathway.[25] Polarity can be described in planarians that the anterior part of the wound site will create a head of a planaria, and the posterior side will create the tail.[25]

References

  1. ^ "Medical Definition of EPIMORPHOSIS". www.merriam-webster.com. Retrieved 2018-02-19.
  2. PMID 29721325
    .
  3. S2CID 25299267
    .
  4. ^
    doi:10.4052/tigg.8.357
    .
  5. S2CID 2978615
    .
  6. S2CID 24804711
    .
  7. ^ a b "Thomas Hunt Morgan's Definition of Regeneration: Morphallaxis and Epimorphosis". The Embryo Project Encyclopedia. Retrieved 2018-02-19.
  8. S2CID 4166243
    .
  9. OCLC 992170104.{{cite book}}: CS1 maint: location missing publisher (link
    )
  10. PMID 15473858
    .
  11. S2CID 25299267
    .
  12. ^ a b c d e Gilbert SF (2014). Developmental Biology (Tenth ed.). Sunderland, MA, USA: Sinauer Associates, Inc. pp. 571–573.
  13. ^
    S2CID 25299267
    .
  14. ^ Issues in Biological, Biochemical, and Evolutionary Sciences Research. Atlanta, GA: ScholarlyEditions. 2012. p. 464.
  15. S2CID 83821328
    .
  16. S2CID 28442979
    .
  17. ^
    PMID 17335428
    .
  18. doi:10.4052/tigg.8.357
    .
  19. PMID 19104667
    .
  20. PMID 26894631
    .
  21. S2CID 28379017
    .
  22. ^
    PMID 37281333
    .
  23. PMID 15473858
    .
  24. S2CID 8085897
    .
  25. ^
    doi:10.1086/ahr/17.4.809
    .
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