A first-ever tissue implant to safely treat a common jaw defect, temporomandibular joint dysfunction, has been successfully tested in animals by researchers from UC Irvine and UC Davis.
“We were able to show that we could achieve exceptional healing of the TMJ area after eight weeks of treatment,” said UCI Distinguished Professor of biomedical engineering Kyriacos Athanasiou, senior author on the study, published Wednesday in Science Translational Medicine. Athanasiou, who joined UC Irvine last year after several years at UC Davis’ Department of Biomedical Engineering, has been working on the condition for nearly two decades.
About 25 percent of adults worldwide – 90 percent of them premenopausal women – have difficulty eating and talking, chronic mouth pain, arthritis and other issues due to degeneration in the cartilage disc that hinges together two key jawbones.
“We hope this will lead to new treatments for humans,” said Natalia Vapniarsky, a veterinary pathologist at UC Davis’ School of Veterinary Medicine, where the surgery was done. “Most medical management approaches for TMJ disc issues currently aren’t curative but palliative. Patients come back needing further help, but by that time, the disc and joint are destroyed beyond repair, so all that can be offered is a prosthetic. We wanted to explore an earlier, regenerative solution.”
Cartilage grown from rib tissue
The team, which also included researchers at the University of Texas School of Dentistry at Houston, removed a tiny bit of existing rib tissue, isolated its cartilage cells and utilized them to tissue-engineer jaw disc cartilage via a “self-assembling” process. They then surgically inserted the new cartilage into the faulty hinge point of the jaw joint of another animal. Two months later, the defects were completely gone.
The experimental work was done in mini pigs because they are omnivorous and have comparable dentition to humans with a similar mechanical loading of the joint components.
Researchers and physicians have long struggled to effectively treat TMJ afflictions. One infamous technique involved putting Teflon into the jaw area; the substance disintegrated, with bits ending up in the brain and elsewhere.
The next steps will be to ensure long-term effectiveness and safety of the implant in animal studies, leading to clinical trials in humans.
Unlike other tissues and organs, cartilage from one body is not rejected when implanted in another body. On the other hand, cartilage does not naturally repair itself and is difficult to grow in the laboratory.
Athanasiou said the results might also apply to the treatment of hip, knee and other joint problems.
“This is the first time that cogent healing has been shown in the TMJ area and, I dare say, the first time anyone has shown successful biomechanical healing in any joint. It’s key that we can achieve regeneration of an ailing tissue with our engineered implant, one that’s mechanically suited to withstand stresses,” Athanasiou said. “So we believe this represents an important first in all joint healing studies.”
Additional authors on the paper are: Le W. Huwe and Boaz Arzi at UC Davis; Jerry Hu at UC Irvine; James Wilson, University of Texas School of Dentistry, Houston; Meghan Houghton, National Science Foundation; and David Hatcher, Diagnostic Digital Imaging Center, Sacramento. The work was supported by the National Institutes of Health.
Vapniarsky, who is first author on the study, completed a Ph.D. in Athanasiou’s lab while he was at UC Davis.
Joint venture: UCI, others create breakthrough treatment for crippling jaw disease (UC Irvine news release)
Tissue engineering toward temporomandibular joint disc regeneration (Science Translational Medicine)
This story was adapted from a UC Irvine news release with additions from Trina Wood, writer in the UC Davis School of Veterinary Medicine.