The 20 million Americans suffering from osteoarthritis are all too familiar with the paucity of treatment options for the painful disease. Most just take anti-inflammatory drugs and learn to deal with the pain.
But what if osteoarthritis could be stopped before it started? That’s exactly what Rice University’s Kyriacos Athanasiou hopes to accomplish through his latest research, a $1.3 million tissue-engineering program aimed at growing replacement cartilage for those suffering from knee injuries.
The research centers on the meniscus, a kidney-shaped wedge of cartilage about the size of a man’s wristwatch. The meniscus fits between the rotating surfaces of the knee, cushioning the stress of walking and running by spreading the load over a wider area of the joint. This reduction of mechanical stress is critical because it is repeated mechanical stress in the joints that causes osteoarthritis, the form of arthritis that attacks most people as they age.
“Removing the meniscus creates a concentration of stress in a single spot in the joint, and that gives birth to osteoarthritis,” said Athanasiou, professor of bioengineering.
But removing the meniscus often is necessary because once damaged, it can never heal. Some 750,000 Americans have all or part of a meniscus removed each year, primarily due to sports-related injuries and auto accidents. If surgeons could replace the damaged meniscus instead, they could reduce the chances for early onset osteoarthritis in each of those patients.
The push to grow menisci via tissue engineering follows three years of preliminary research by Athanasiou and colleagues in Rice’s Musculoskeletal Bioengineering Laboratory (MBL). During that time, the researchers have established basic methods for growing cartilage in the lab using tissue engineering.
Tissue engineering, a relatively new field of research, combines the latest techniques in bioengineering and biotechnology with the latest advances in materials science. The goal of tissue engineering is to use a patient’s own cells to grow replacement tissue outside the body. The lab-grown organs and grafts can then be transplanted back into the patient without any risk of rejection.
The cartilage-growing techniques developed at MBL include a number of methods of spurring cells to multiply by simulating the conditions the cells would experience inside the body. This includes mechanical stimulation — machines literally compress, tumble and stretch the tissue as it is growing — followed by periods of rest and relaxation.
Rather than growing slabs of cartilage and carving out meniscus-shaped pieces, Athanasiou and colleagues are attempting to grow the replacement meniscus in the exact shape needed.
This marks the first time that researchers in any lab have tried to grow menisci in a predetermined shape, but Athanasiou said it is vital because doing so will allow the researchers to precisely simulate the conditions inside the knee during tissue growth. That will make it less likely that the replacements will fail once they are subjected to the high-stress environment of the knee following implantation.
The research is funded under a five-year grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases.