Some animals can regrow an amputated limb—or even a severed head! Scientists are studying these incredible creatures to help treat human diseases. If you’ve ever accidentally cut yourself, you probably didn’t think much about the scab or new skin that formed. The process of healing, repairing, and replacing damaged tissue is what scientists call regeneration.
In the case of a scraped knee, it’s mostly just skin that’s regrowing. But all around us, living things demonstrate mind-blowing abilities to regenerate entire limbs, internal organs, even a full-grown body from a bit of tissue.
“Scientists in the field of regenerative medicine look at animals that can naturally regenerate and heal types of wounds that humans can’t,” explains Thomas Lozito, Ph.D., assistant professor at the University of Southern California in Los Angeles, who was fascinated by reptiles and amphibians as a child. “We try to map out a blueprint for getting humans to do the same thing,” says Dr. Lozito. (Today he runs a lab with over 1,000 lizards!)
Take the axolotl, a salamander that can lose its entire tail—and grow it back. Or organisms known as hemichordates, which can lose their heads and then create new ones! Or the hydra, a freshwater creature that regenerates its cells every 20 days.
Regenerative medicine is a field of science that focuses on restoring or healing damaged body parts so that they function normally. The long-term goal is to stimulate tissue and organs to heal themselves.
Scientists study these research organisms to learn how their regenerative processes work. Their goal: to use their understanding to develop treatments for human health issues like spinal cord injuries, Alzheimer’s disease, the loss of an arm or a leg, and much more.
Celina Juliano, Ph.D., assistant professor at the University of California, Davis, was also an animal lover as a kid. Today she studies the hydra—one of the first animals in which regeneration was discovered, way back in the 1700s. A hydra is a minuscule freshwater creature that’s related to jellyfish, sea anemones, and coral. It’s basically a tube with tentacles on the top and a sticky disk on the bottom, but it can do amazing things. “A hydra can be cut into little pieces, and each piece will grow back into a full hydra,” Dr. Juliano says. “You can even separate a hydra into single cells, form those cells up into a ball, and they’ll rearrange themselves back into a hydra. And a hydra continually renews itself, replacing all of its cells with new cells.”
Helping others motivates Voot P. Yin, Ph.D., director of scientific services at MDI Biological Laboratory in Maine. Dr. Yin works with zebrafish, salamanders, and mice. “We have found that zebrafish can fully regenerate a missing or damaged muscle, even in their heart,” he says. Many of the genes in zebrafish are closely related to those in humans. One of the major goals of regenerative medicine is discovering how to decode the genetic circuitry that allows regeneration to occur. “Then we need to reactivate those circuits in humans, so that if you have an injury like a heart attack, we can use the body’s own genetic programming to allow regeneration to happen,” Dr. Yin explains. This type of research can lead to important discoveries in regenerative medicine that can be applied to almost any organ system.
The quest to make people’s lives better will continue to ignite scientists’ imaginations. And maybe it will also lead you on a journey into the exciting field of regenerative medicine!