Salamander legs, mouse ears and pig powder.

Almost a decade ago, Ellen Heber-Katz observed something strange while performing experiments on a strain of mice known as MRL. She was studying autoimmune diseases and her team had punched holes into the subject’s ears for identification. Three weeks later, the holes were gone. Further studies revealed that these mice could also heal damage to their hearts. The secret lay in its ability to form something called a blastema. Regular mice, and humans, would just form a scar instead. A blastema is a mass of undifferentiated cells. It is what enables lower vertebrates, salamanders for example, to regrow lost limbs.

While we are still a long way off from regrowing whole limbs in people, a company called ACell Inc. founded by a former Harvard surgeon Dr. Alan Spievack, has developed an extract of pig bladder for promoting tissue regeneration. The pig powder is currently used to promote healing in certain medical procedures and it is considered to be capable of regrowing a severed fingertip.


PS: And Electricity...
While the effects of electricity on development have been known for over a century, it is only now that scientists are beginning to understand the mechanisms involved at the cellular level. A recent study has revealed the electrical mechanism which allows tadpoles to regrow a severed tail. Researchers believe that gene therapy could one day enable humans to heal injuries by exploiting the same mechanism.