Research from the lab of McGowan Institute 
for Regenerative Medicine Associate Director Rocky Tuan, PhD, was recently presented by postdoctoral fellow Thomas Lozito, PhD, at the Orthopaedic Research Society’s (ORS) 2014 Annual Meeting in New Orleans. Dr. Lozito shared with the audience the results of their study on lizard cartilage.
Cartilage is the connective tissue found throughout the body. As a result of injury or disease, cartilage can become damaged or even wear away causing pain and discomfort. Unlike muscle, human cartilage does not have the ability to heal itself. As a result, millions of people suffer from pain and stiffness caused by damaged cartilage.
While the inability of cartilage to heal itself is the unfortunate reality for most higher vertebrates, there is one notable exception: the lizard. Lizards possess the unique ability to regrow their tail. However, the newly grown tail has no bones. Instead, the “skeleton” consists of cartilage hearty enough to support the new tail.
The fascinating and unique ability to regrow cartilage has made Dr. Lozito and Dr. Tuan, Director of the Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, take a closer look at these reptiles.
“We study lizard cartilage,” Dr. Lozito explained, “to understand how it is able to be maintained in such a robust state. We have identified several key molecules known to play roles in normal skeletal development that are turned on in unusual and interesting patterns during lizard tail cartilage growth. These molecules are responsible for the unique tissue properties of regenerated lizard cartilage.”
The lizard’s ability to regenerate cartilage is of particular interest to researchers since scientists have been unable to successfully replicate this ability in humans.
“So far, our best attempts to engineer cartilage tissue in the lab often results in cartilage that eventually calcifies and is replaced by bone,” Dr. Lozito said. This does little to help those who suffer from injury or degenerative joint diseases, such as osteoarthritis.
What’s next for the team of researchers? For starters, the team plans to study what properties of the regenerated lizard tail make it conducive for cartilage growth.
“We have evidence that lizard cells themselves are particularly primed for differentiating into cartilage,” Dr. Lozito said, “and that lizard cartilage itself contains a population of stem cells that readily forms new cartilage in response to trauma. This is practically the opposite of what occurs following damage to human cartilage.”
Down the road, the team hopes that what they learn from our reptile friends will help the human population. “We believe identifying the signals and cellular properties underlying the regenerative power of lizard tail cartilage will afford new insights into actual cartilage regeneration and potentially yield lizard-inspired therapeutics and treatments for human cartilage diseases.”
Illustration: Wikipedia.