Injuries to the articular cartilage in different joints, including the knee, are painful and limit mobility. Therefore, researchers at the University of Basel and University Hospital Basel are developing cartilage implants using cells from the patient's nasal septum. A recent study shows that giving these cartilage implants more time to mature significantly improved clinical efficacy, even in patients with complex cartilage injuries. This suggests that the method could also be suitable for the treatment of degenerated cartilage in osteoarthritis.
An unlucky fall while skiing or playing football can spell the end of sports activities. Damage to articular cartilage does not heal by itself and increases the risk of osteoarthritis. Researchers at the University of Basel and the University Hospital Basel have now shown that even complex cartilage injuries can be repaired with replacement cartilage engineered from cells taken from the nasal septum.
A team led by Professor Ivan Martin, Dr. Marcus Mumme and Professor Andrea Barbero has been developing this method for several years. It involves extracting the cells from a tiny piece of the patient's nasal septum cartilage and then allowing them to multiply in the laboratory on a scaffold made of soft fibers. Finally, the newly grown cartilage is cut into the required shape and implanted into the knee joint.
Earlier studies have already shown promising results. "Nasal septum cartilage cells have particular characteristics that are ideally suited to cartilage regeneration," explains Professor Martin. For example, it has emerged that these cells can counteract inflammation in the joints.
More mature cartilage shows better results
In a clinical trial involving 98 participants at clinics in four countries, the researchers compared two experimental approaches. One group received cartilage grafts that had matured in the lab for only two days before implantation – similar to other cartilage replacement products. For the other group, the grafts were allowed to mature for two weeks. During this time, the tissue acquires characteristics similar to native cartilage.
For 24 months after the procedure, the participants self-assessed their well-being and the functionality of the treated knee through questionnaires. The results, published in the scientific journal Science Translational Medicine, showed a clear improvement in both groups. However, patients who received more mature engineered cartilage continued to improve even in the second year following the procedure, overtaking the group with less mature cartilage grafts.
Magnetic resonance imaging (MRI) further revealed that the more mature cartilage grafts resulted in better tissue composition at the site of the implant, and even of the neighboring cartilage. "The longer period of prior maturation is worthwhile," emphasizes Anke Wixmerten, co-lead author of the study. The additional maturation time of the implant, she points out, only requires a slight increase in effort and manufacturing costs, and gives much better results.
Particularly suited to larger and more complex cartilage injuries
"It is noteworthy that patients with larger injuries benefit from cartilage grafts with longer prior maturation periods," says Professor Barbero. This also applies, he says, to cases in which previous cartilage treatments with other techniques have been unsuccessful.
"Our study did not include a direct comparison with current treatments," admits Professor Martin. "However, if we look at the results from standard questionnaires, patients treated with our approach achieved far higher long-term scores in joint functionality and quality of life."
Based on these and earlier findings, the researchers at the Department of Biomedicine now plan to test this method for treating osteoarthritis – an inflammatory disease that causes joint cartilage degeneration, resulting in chronic pain and disability.
Two large-scale clinical studies, funded by the Swiss National Science Foundation and the EU research framework program Horizon Europe, are about to begin. These studies will explore the technique's effectiveness in treating a specific form of osteoarthritis affecting the kneecaps (i.e., patellofemoral osteoarthritis). The activities will further develop in Basel the field of cellular therapies, strategically defined as a priority area for research and innovation at the University of Basel and University Hospital Basel.
