Regeneration and Regrowth Potentials of Digit Tips in Amphibians and Mammals

Figure 1

The blastema is a group of cells originating from the limb tissue local to the amputation site. (a) It was originally speculated that the blastema is a homogeneous structure of multipotent cells (purple dots), which would then form all the structures of the amputated digit tip or limb. (b) However, recent studies in the regeneration of both axolotl limb and zebrafish fin have demonstrated that the blastema cells are a heterogeneous assortment of lineage-restricted, unipotent progenitor cells (colorful dots). (c) Cell transdifferentiation might also play a role in the formation of blastema cells. Dermis and skeletal tissue, both of lateral plate mesodermal origin, have been shown to transdifferentiate. The blue area in (a, b) represents the remaining tissues following digit amputation.

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