Every year, thousands of individuals lose appendages or entire limbs in terrible accidents. Prosthetics have helped amputees regain basic function for decades through successful transplant surgery. But wouldn’t it be great if humans could simple re-grow lost limbs on their own? Scientists now say that this seemingly superhuman power might in fact become a true reality one day, all thanks to an unsuspected creature. The cold blooded Axolotl, an indigenous salamander of Mexico, appears to have an amazing ability to regenerate whole limbs that were lost to injury. Researchers say they are diligently working night and day, to find out what the amphibian has that humans don’t.

What would you do with a new hand?

“The crux of what we are doing with this work is to be able to understand the basic biology of regeneration, and then translate that to regenerative therapies,” said biologist David Stocum, director of the Center for Regenerative Biology and Medicine at Indiana University. Stocum and his team of researchers got a little closer to unlocking the key to regeneration, reporting the data in the journal Bio Med Central Biology. They found that a cellular protein called EVI5 appears to give cells at the wound site time to regroup, so they can begin to produce varied tissues needed to repair or regrow tissue. In the Mexican salamander, the site of amputation does not close over with scar tissue as it does in most other animals. Instead, a bump of cells called a blastema forms at the injured area. The cells huddle together and undergo a scientific process called “de-differentiation,” whereby each cell becomes oriented towards a particular tissue typed needed to replace the salamander limb, or bone, muscle, and nerve. Stocum and his team confirmed that this amazing process relies on a complex chain of interconnected chemical signals that remain mysterious, and are not found in humans and other living creatures. The discovery of the EVI5 protein has lead researchers to understand the mysterious chemical signals that undergo during the process of regeneration. According to Dr. Stephen Badylak, incoming president of the Tissue Engineering and Regenerative Medicine International Society, a close look at the axolotl is crucial, because “we need to identify what [the human] deficiencies are and then say, ‘Is it possible for us to do something like that or not? Do we even have it in our genome?'”. Badylak remains optimistic that the regeneration of human fingers or limbs remains a possibility but may still be decades away from actually happening. Stocum agreed that regenerative medicine should make smaller but still valuable medical gains. In the meantime, he said, researchers are creating better and more sensitive prosthetics for today’s amputees — devices that would have been unimaginable even a few years ago. Still, Stocum admitted, “nothing does beat the real thing.” SOURCE: David Stocum, Ph.D., professor, department of biology, and director, Center for Regenerative Biology and Medicine, Indiana University, Bloomington; Nov. 30, 2009, BioMed Central Biology, online – Anthony Isaac Palacios