US researchers have made progress in producing engineered tissue that could one day be used to provide new treatments for injuries and damage to the joints.
Biomedical engineers at the University of California – Davis (UC Davis) have been exploring ways to toughen up engineered cartilage and keep natural tissues strong outside the body. During their research they have maintained native cartilage in the lab and cultured cartilage cells, or chondrocytes, to produce engineered cartilage.
One method that is currently used for treating serious joint problems is transplants of native cartilage. But this method is not sufficient as a long-term clinical solution.
Engineered tissues, meanwhile, lack the mechanical properties of native tissue, explained Eleftherios Makris, a postdoctoral researcher at the UC Davis Department of Biomedical Engineering and first author on the paper.
At present, engineered cartilage has yet to be tested or approved for use in humans.
Knee joints are normally low in oxygen, so the team looked at the effect of depriving native or engineered cartilage of oxygen. In both cases, low oxygen led to more cross-linking and stronger material. They also found that an enzyme called lysyl oxidase, which is triggered by low oxygen levels, promoted cross-linking and made the material stronger, UC Davis reported.
According to Professor Kyriacos A. Athanasiou, a distinguished professor of biomedical engineering and orthopedic surgery, and chair of the Department of Biomedical Engineering, this work has important ramifications with respect to tissue grafts used in surgery, as well as new tissues fabricated using the principles of tissue engineering.
It means that grafts such as cadaveric cartilage, tendons or ligaments – which are known to lose their mechanical characteristics in storage – can now be treated with the processes developed at UC Davis to make them stronger and fully functional, he said.
Additionally, many tissue engineering methods may now be altered to take advantage of this strengthening technique, Athanasiou believes.
The findings of the study have been published in the journal Proceedings of the National Academy of Sciences.