title: The impact of low levels of collagen IX and pyridinoline on the mechanical properties of in vitro engineered cartilage.
abstract: The application of in vitro engineered cartilage has become a promising approach to repair cartilage defects. Nevertheless, the poor mechanical properties of in vitro engineered cartilage limit its potential for clinical applications. Studies have shown that the extracellular matrix (ECM) components are strongly correlated with the mechanical strength of engineered cartilage, but it remains unclear which components play a key role in determining the mechanical property of engineered cartilage. To address this issue, quantitative analyses of cartilage-specific components among native cartilage, in vivo and in vitro engineered cartilages were performed, and the correlation between various ECM molecules and Young's modulus was further analyzed. The results showed that many ECM molecules, such as highly sulphated glycosaminoglycan (GAG), collagens II, IX, and pyridinoline (PYR), contributed to the mechanical strength of cartilages. Further comparison between in vitro engineered cartilage and stress-stimulated in vitro engineered cartilage, known to have stronger mechanical properties, showed that only collagen IX and PYR, but not GAG and collagen II, were the key factors determining the mechanical properties of in vitro engineered cartilage. These results indicate that in vitro environment lacks the niche for enhancing collagen crosslinking that is mediated by collagen IX and PYR during cartilage formation. Thus, the discovery provides a clue for engineering strong cartilage in vitro in the future by enhancing the levels of these two molecules.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, 639 Zhi Zao Ju Road, Shanghai 200011, PR China.
authors.forename: Dan
authors.initials: D
authors.lastname: Yan
authors.forename: Guangdong
authors.initials: G
authors.lastname: Zhou
authors.forename: Xu
authors.initials: X
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Wen Jie
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Xusong
authors.initials: X
authors.lastname: Luo
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Jiang
authors.forename: Lei
authors.initials: L
authors.lastname: Cui
authors.forename: Yilin
authors.initials: Y
authors.lastname: Cao
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D001696:Biomechanical Phenomena / Q000187:drug effects*; D002356:Cartilage / Q000737:chemistry* / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology*; D006801:Humans; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000596:Amino Acids; C015484:pyridinoline; D003094:Collagen