The molecules that control human cartilage repair are the same as the more active ones in salamanders, zebrafish, and other animals that can regrow limbs, according to Duke Health researchers.
The researchers found evidence of an innate capacity for human cartilage to repair itself, according to the study released on Oct. 9. This contradicts the historical notion that joint cartilage cannot be repaired in humans.
The study found that cartilage proteins in ankles are younger than those in knees, and knee cartilage proteins are younger than those found in hips. This aligns with how some animals regenerate limbs more quickly near the tips of a limb than near the body.
The key seems to be microRNA, and unlocking its secrets may lead to advancements in osteoarthritis, and even regrowth of human limbs, the researchers said. They said injecting the right microRNA cocktail into a damaged joint or limb might someday enhance the body’s ability to repair itself.
“We believe that an understanding of this ‘salamander-like’ regenerative capacity in humans … could provide the foundation for new approaches to repair joint tissues and possibly whole human limbs,” senior author Virginia Byers Kraus, M.D., Ph.D., a professor in the departments of Medicine, Pathology, and Orthopedic Surgery at Duke, told ScienceDaily.
To reach this goal, further research is needed to identify the factors that are expressed in limb-regenerating animals that are no longer expressed in humans.
What Is Osteoarthritis?
Osteoarthritis is a form of arthritis that features the breakdown and eventual loss of the cartilage of one or more joints, according to MedicineNet Chief Editor William C. Shiel Jr., MD, FACP, FACR. He says that of more than 100 different types of arthritis conditions, osteoarthritis is the most common joint disease.
The condition most commonly affects the hands, feet, spine, and large weight-bearing joints, such as the hips and knees, he said.
Besides losing weight and avoiding joint stress, Dr. Shiel said there is currently no specific medical treatment to halt cartilage degeneration or to repair damaged cartilage in osteoarthritis.
Why Are Amputations Performed?
Limbs are usually amputated to stop the spread of gangrene, a localized area of tissue death, Dr. Shiel said. This can be caused by an accident, animal attack, or battlefield injury, among other causes.
Sometimes limbs must be removed to curtail loss of blood and infection in a person who has suffered severe, irreparable damage to a limb, Dr. Shiel said. At other times it is performed to stop the spread of bone cancer.