The regenerating antler blastema: the derivative of stem cells resident in a pedicle stump.

Antlers of the deer are the only mammalian organs that can fully grow back once lost from their pedicles, hence offer the only opportunity to learn how nature has bestowed mammalian epimorphic regeneration. Investigations have demonstrated that it is the proliferation and differentiation of pedicle periosteal cells (PPCs), but not dedifferentiation of the local differentiated cells, that give rise to the antler blastema. PPCs express key embryonic stem cell markers and can be induced to differentiate into multiple cell lineages, so are termed antler stem cells. Further research has found that PPCs can initiate antler regeneration only when they have interacted with cells of the pedicle skin. Histologically, the process of early antler regeneration resembles that of healing of a mouse leg stump wound. However what sets these two apart is the difference in proliferation potential between the PPCs and the periosteal cells of the long bone. We believe that if we can impart a greater proliferation potential to the long bone periosteal cells, we might be able to achieve the dream of regenerating limbs in mammals.