(Reuters Health)—Doctors might one day be able to harvest cells from patients’ noses to produce cartilage that can be transplanted into damaged knee joints, a small experiment suggests.
Because the experiment only included 10 adults who were followed for just two years, it’s impossible to say for sure whether this procedure would be safe or effective with widespread use. But the results are promising enough to merit more testing, says study co-author Ivan Martin of the University of Basel in Switzerland.
“We have developed a new promising approach to the treatment of articular cartilage injuries,” Martin says by email. “Before this can be offered to patients as a standard treatment, obviously it needs to be tested in larger patient cohorts and in randomized and controlled trials with long-term assessment of clinical outcome.”
Previous research has found cells extracted from the septum can be used to grow new cartilage in a lab, Martin says. With the current experiment, researchers successfully implanted this lab-grown tissue into knee joints for the first time, he says.
To do this, researchers first performed a minimally invasive procedure using local anesthesia to harvest a small specimen, about 6 mm or a quarter of an inch, of tissue from the nasal septum.
Next, they grew the harvested cells in a lab for two weeks, then cultured them for another two weeks on a collagen membrane scaffold to grow thin sheets of cartilage measuring 30 mm by 40 mm, or about 1.2 inches by 1.5 inches.
Researchers trimmed these grafts to the right shape to replace the damaged cartilage removed from each patient’s knee joint, then implanted the replacement tissue.
Two years after reconstructive surgery, most recipients reported improvements in pain, knee function and quality of life, researchers reported Oct. 22 in The Lancet.
MRI scans at two years also showed the growth of new tissue similar to native knee cartilage around where the replacement tissue was implanted, the study found.
Researchers didn’t see any adverse reactions or dangerous side effects.
Every year, around 2 million people in the U.S. and Europe alone are diagnosed with damage to articular cartilage because of injuries or accidents, the researchers note.
Because the tissue doesn’t have its own blood supply, it has limited capacity to repair itself once damaged, leading to degenerative joint conditions, such as osteoarthritis.
Traditional methods to prevent or delay onset of cartilage degeneration don’t create the healthy cartilage needed to endure the forces of everyday movement, the authors contend.
Efforts to use patients’ own healthy articular cartilage cells from a healthy joint to repair damaged knee tissue haven’t been able to reliably restore function over the long term, the researchers argue.
“In my eyes, the major advantage (of the experimental procedure using nasal tissue) is that there is no need to obtain cartilage from within a healthy joint,” says Dr. Nicole Rotter of Ulm University Medical Center in Germany, author of an accompanying editorial.
“Potential harms include side effects to the new donor site, the nose, such as deformities of the nose and functional problems such as nasal obstruction,” Rotter adds by email. “These negative side effects can be avoided with an appropriate surgical technique to obtain the biopsy, meaning this is a surgery that should be done by a person with expertise in nasal surgery such as an otorhinolaryngologist.”
Beyond that, more research is needed to see how this procedure works in the knee joint over a longer period of time, Rotter adds.
“Long term stability and integrity need to be investigated, as a potential risk could be that these transplants are not stable in the long run,” Rotter says.
- Mumme M, Barbero A, Miot S, et al. Nasal chondrocyte-based engineered autologous cartilage tissue for repair of articular cartilage defects: an observational first-in-human trial. The Lancet. 22 Oct 2016. 388(10055):1985–1994.
- Rotteremail N, Brenner RE. Cartilage repair across germ layer origins. The Lancet. 2016 Oct 22. 388(10055):1957–1958.