Salamanders routinely regenerate limbs and other appendages after being injured in ways that would leave mammals paralyzed or even worse. A team of researchers associated with the University of Florida McKnight Brain Institute’s Regeneration Project has begun examining the genes of the Mexican axolotl salamander with a view to finding out why it is capable of such regeneration, and hopefully applying these findings to humans.
"The axolotl is the champion of vertebrate regeneration, with the ability to replace whole limbs and even parts of its central nervous system," said Edward Scott, Ph.D., principal investigator. "These salamanders use many of the same body systems and genes that we do, but they have superior ability to regenerate after major injuries. We think that studying them will tell us a lot about a patient’s natural regenerative capacities after spinal cord injury and nerve cell damage."
The issue of what controls organ regeneration was named among the top 25 major questions facing scientists in the next quarter century by Science magazine in 2005, Scott said. With medical science continually adding years to the human lifespan, the importance of "rebuilding and restoring" old tissues and organs is growing. Even without help, people are capable of a certain degree of regeneration. Humans can re-grow fingertips and even more than half of their liver. But they cannot replace whole limbs and restoring parts of their brain and spinal cord is a daunting challenge.
"We’ve analyzed genes in common between the axolotl salamander and humans, and found out we share about 90% of our genes in a one-to-one sense," said S. Randal Voss, director of the Salamander Genome Project at the University of Kentucky. "It could be that small but important changes in the way these genes function in an injury environment affect the repair process, but somehow the salamander is able to use these genes for regeneration, while people are not."