It sounds like science fiction, but scientists may have just taken a giant step toward a future where amputees regrow real limbs.
Researchers studying axolotl salamanders, zebrafish and mice say they’ve uncovered a powerful set of genes that appear to control regeneration itself.
The breakthrough, published in the Proceedings of the National Academy of Sciences, could one day help scientists develop therapies that regrow living tissue, bone and even entire arms and legs in humans.
“This significant research brought together three labs, working across three organisms to compare regeneration,” said Wake Forest University biologist Josh Currie, whose lab studies the Mexican axoloti salamander, in Science Daily. “It showed us that there are universal, unifying genetic programs that are driving regeneration in very different types of organisms, salamanders, zebrafish and mice.”
The project also included Duke University plastic surgeon David A. Brown, who studies digit regeneration in mice, and Kenneth D. Poss of the University of Wisconsin-Madison, whose research focuses on fin regeneration in zebrafish.
Axolotls — a type of salamander — are famous for their extraordinary ability to regrow entire limbs along with tails, spinal cord tissue, and parts of organs including the heart, brain, lungs and liver.
Zebrafish can repeatedly regrow damaged tail fins. Their bodies are also capable of repairing the heart, brain, spinal cord, kidneys, retinas and pancreas.
Mice were included because, like humans, they’re mammals. Mice can regenerate the tips of their digits, and humans can sometimes regrow fingertips if the nailbed remains intact after injury, allowing skin, flesh and bone to regenerate.
The stars of the study were two genes called Specificity Protein 6 or SP6 and SP8. Scientists discovered that when these genes switched on, animals were able to trigger extraordinary healing abilities.
But when researchers used the gene-editing tool CRISPR to remove SP8 from axolotls, the animals suddenly lost the ability to properly regrow limb bones.
The same thing happened in the mice. Then, using new DNA-altering technology, they partially restored bone regrowth in mice that had lost their regenerative powers.
The exciting conclusion was that the same technology may apply the same genetic changes in humans.
Around the world, more than 1.5 million amputations occur every year, according to limb loss statistics, mostly due to diabetes complications. Around 65 million people worldwide live with limb amputations.
Human beings cannot regrow arms or legs, but the findings suggest our bodies may still contain ancient regeneration programs from 350 million years ago, waiting to be reactivated.
“The gene-therapy approach in this study is a new avenue that can complement and potentially augment what will surely be a multi-disciplinary solution to one day regenerate human limbs,” said Currie.
