A team of bioengineers managed to regenerate the cartilage of a rabbit’s knee; thanks to a structure made of a biodegradable polymer that has a property called piezoelectricity and; when squeezed, it produces a small burst of electrical current.
A team from the University of Connecticut (USA) managed to regrow cartilage in the animal’s joint; which represents “a promising leap towards the healing of joints in humans,” says the educational center.
Arthritis is a common and painful disease caused by joint damage; where normally cartilage pads cushion these points, but injuries or age can wear it down and the bones begin to rub against each other.
The best available treatments try to replace the damaged cartilage with a healthy piece taken from another part of the body or from a donor..
Some researchers have tried to induce the body to grow new cartilage by amplifying chemical growth factors; and other attempts rely on a kind of bioengineered “scaffold” for a new tissue base.
But nevertheless; the regenerated cartilage “breaks down under normal joint stresses,” according to University of Connecticut (UConn) bioengineer Thanh Nguyen.
The study published today by Science Translational Medicine describes the method used by Nguyen’s lab, which discovered that electrical signals are critical for normal cartilage growth.
The team designed a tissue scaffold made of poly-L-lactic acid (PLLA) nanofibers, a biodegradable polymer that is often used to suture surgical wounds and has piezoelectric properties.
Regular movement of a joint, such as that of a person walking, can cause the PLLA scaffold to generate a weak but constant electrical field that encourages cells to colonize it and become cartilage, explains UConn.
The researchers tested the technique on the knee of an injured rabbit, which was allowed to get on a treadmill for exercise after the scaffold was implanted, and “as expected, the cartilage grew back normally.”
Piezoelectricity is a phenomenon that also exists in the human body. Bone, cartilage, collagen, DNA, and various proteins have such a response.
Nguyen considers the result “fascinating”, although he prefers to remain cautious because they have yet to test it in an animal with a size and weight similar to those of the human being.
Additionally, they want to observe the treated animals for at least a year, to make sure the new cartilage is durable.
The scientist considers that “it would also be ideal to test PLLA scaffolds in older animals”, since in people arthritis is usually a disease of old age.