Damaged knee joints repaired with nose cells
Damage can lead to degenerative joint conditions such as osteoarthritis that affects about one in eight
Researchers have conducted the first human tests of transplants to repair damaged knees using cartilage cells harvested from the noses of a small number of patients.
Because of injuries and accidents, damage to articular cartilage — tissue on the end of a bone that cushions the surface of the joint and is vital for painless movement — is common.
Since this tissue lacks its own blood supply, damage to it can lead to degenerative joint conditions such as osteoarthritis.
The Arthritis Alliance of Canada says the condition affects about one in eight Canadians.
More specifically, every year around 2 million people across Europe and the U.S. are diagnosed with damage to articular cartilage.
But there are no gold-standard treatments to prevent or delay cartilage degeneration. Current options include microfracture surgery, which involves piercing very small holes near the damaged cartilage to stimulate a healing response, or transplanting patients' own articular cartilage cells, such as from the other knee.
In this new approach, Swiss researchers used engineered cartilage tissue grown from subjects' own nasal septums.
Lead author Ivan Martin, a professor of tissue engineering at the University of Basel, and his colleagues describe their early-stage study on 10 patients aged 18 to 55 with knee lesions in Wednesday's online issue of the medical journal The Lancet.
Investigators took biopsy specimens that were 6 mm in diameter from the nasal septum, under local anaesthetic.
Then they grew the harvested cells in the lab for two weeks. The cartilage grafts were further prepared and then cut into the right shapes.
Finally, surgeons used the engineered grafts to replace damaged cartilage that was removed.
Nine subjects reached two years of follow-up (one was excluded because of an unrelated sports injury).
Even though the level of repaired tissue appeared to vary among patients and over time, MRI scans at two years showed new tissue developed with similar properties to the original cartilage.
The nine recipients reported improvements in use of their knees and better pain scores compared to before their surgeries.
No side-effects were reported.
Investigators plan to extend the study to 25 patients and to follow them for longer.
The lack of mechanical tests and a control group mean it's possible that the self-reported improvements were a result of the placebo effect, the researchers acknowledged.
Treatment of articular cartilage injuries remains an important clinical problem, said Dr. Nicole Rotter and Dr. Rolf Brenner from Ulm University Medical in Germany in a journal commentary.
"Overall, this first-in-human trial represents an important advance towards less invasive, cell-based repair technologies for articular cartilage defects," they wrote.
"However, long-term results …and analysis of cost-effectiveness will be needed to establish whether this technology has the potential to be approved by the European Medicines Agency and the U.S. Food and Drug Administration."
The editorial authors cautioned that potential side effects at the harvest site in the nose also need to be examined and reported with special care.
Dr. Moin Khan of the orthopedics department at the University of Michigan in Ann Arbor called the results preliminary but encouraging.
"Cartilage injuries in the knee are a challenging problem and unfortunately our current treatment options have limited long term results and are based on studies of relatively poor quality," Khan said in an email.
"The technique reported on by the authors is still experimental and based on the results from a few patients. Further research involving more patients will be required to truly establish if the technique described is significantly better than our current treatment options."
The study was funded by Deutsche Arthrose-Hilfe.