According to a new study published in Science Advances, frogs with amputated legs were able to regenerate functional limbs using a wearable bioreactor with a combination of five medications. Although the research is still in its early stages, it is believed that this unique approach could be used for individuals with missing limbs in the coming years and decades. The study’s stars were African clawed frogs, a species that cannot regenerate its own limbs normally. By encapsulating a recently severed stub in a silicone cap containing five pro-healing substances, researchers from Tufts University and Harvard University started the frogs’ dormant regenerative process.
Each medicine served a specific goal, such as lowering inflammation, suppressing collagen formation that leads to scarring, and boosting new nerve fiber, blood vessel, and muscle growth. The frogs wore the drug-dispersing bioreactor around their severed hind leg for only 24 hours before being meticulously observed for the next 18 months. Long-term gains in bone length, soft tissue patterning, and neuromuscular healing were observed in the frogs that got the treatment. Their new limbs had a bone structure similar to that of a genuine limb, a larger number of interior tissues, including neurons, and even some “toes” at the end.
Professor Mike Levin, corresponding study author and pioneering biologist at Tufts University, told IFLScience, “These frogs live entirely underwater, so they swim more than they jump, but their behavior was much more like that of normal frogs – the new legs had feeling, could sense objects, and were used for moving around very well underwater.” Previous research by the scientists revealed that a single medication, progesterone, combined with the BioDome could promote considerable limb regrowth in frogs. These limbs, on the other hand, formed as a single spike and were not quite as functional as those generated in the latest study using five medicines.
Other scientists have attempted limb regeneration in the past utilizing stem cells or gene-editing techniques. However, this new study uses medications and a bioreactor to take a completely different approach. The researchers feel that this method has numerous advantages since it activates the animal’s latent anatomical patterning mechanisms. Professor Levin explains, “This work shows that it’s feasible to elicit a regenerative response in animals that don’t ordinarily do it, without utilizing genetic editing or stem cell implants.”
“Our technique employs a novel medication mixture that has never been used before, as well as a wearable bioreactor to distribute it.” “Unlike some other procedures, there are no stem cell implants or foreign genes added,” he continued. Only a few animals with a spinal cord can regenerate their limbs, most notably salamanders and lizards. While no mammals have been shown to be able to entirely replace severed limbs, some evidence suggests that they may have untapped regenerative abilities. Humans, for example, can regrow their liver to amazing lengths. The researchers plan to try their unique technique on mammals next, with the goal of eventually seeing if a carefully calibrated cocktail of medications might start limb regeneration in humans.
“Unlike some other approaches, the purpose here is to push cells toward the program of building a limb, not to control the process using stem cell 3D printing or anything like that — the goal is to identify a trigger, not to implement all of the intricacies.” This is why our method includes a 24-hour therapy followed by a year of growth — the idea is to take advantage of the cells’ potential to construct intricate structures,” Levin explained. “There’s still a lot of work to be done to see how it’ll be utilized in humans,” he said, “but the future of regenerative medicine is quite promising.”