To make stronger cartilage, cut the oxygen University of California Davis rightOriginal StudyPosted by Andy Fell-UC Davis on October 31 2014Both natural and engineered types of cartilage get stronger in a low-oxygen environment researchers report.Lab-grown tissues could one day provide new treatments for injured or damaged joints tendons and ligaments.Cartilage for example is a hard material that caps the ends of bones and allows joints to work smoothly. Biomedical engineers exploring ways to toughen up engineered cartilage and keep natural tissues strong outside the body report new developments in the Proceedings of the National Academy of Sciences. ��The problem with engineered tissue is that the mechanical properties are far from those of native tissue �� says first author Eleftherios Makris a postdoctoral researcher biomedical engineering department of University of California Davis.While engineered cartilage has yet to be tested or approved for use in humans a current method for treating serious joint problems is with transplants of native cartilage. But it is well known that this method is not sufficient as a long-term clinical solution Makris says.The major component of cartilage is a protein called collagen which also provides strength and flexibility to the majority of our tissues including ligaments tendons skin and bones. Collagen is produced by the cells and made up of long fibers that can be cross-linked together.The team �has been maintaining native cartilage in the lab and culturing cartilage cells or chondrocytes to produce engineered cartilage. ��In engineered tissues the cells produce initially an immature matrix and the maturation process makes it tougher �� Makris says.Knee joints are normally low in oxygen so the researchers 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. ��The ramifications of the work presented in the PNAS paper are tremendous with respect to tissue grafts used in surgery as well as new tissues fabricated using the principles of tissue engineering �� says Kyriacos A. Athanasiou a professor of biomedical engineering and orthopedic surgery and chair of the biomedical engineering department who oversaw the work.Grafts from cadavers such as cartilage tendons or ligamentsâ � �notorious for losing their mechanical characteristics in storageâ � �can now be treated with this new processes to make them stronger and fully functional he says.Athanasiou also envisions that many tissue engineering methods will now be altered to take advantage of this strengthening technique.The National Institutes of Health funded the work.Source: UC DavisYou are free to share this article under the Creative Commons Attribution-NoDerivs 3.0 Unported license.