title: Ectopic tissue engineered ligament with silk collagen scaffold for ACL regeneration: A preliminary study.
abstract: Anterior cruciate ligament (ACL) reconstruction remains a formidable clinical challenge because of the lack of vascularization and adequate cell numbers in the joint cavity. In this study, we developed a novel strategy to mimic the early stage of repair in vivo, which recapitulated extra-articular inflammatory response to facilitate the early ingrowth of blood vessels and cells. A vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was developed and then transferred to reconstruct the ACL in rabbits without interruption of perfusion. At 2weeks after ACL reconstruction, more well-perfused cells and vessels were found in the regenerated ACL with ETEL, which decreased dramatically at the 4 and 12week time points with collagen deposition and maturation. ACL treated with ETEL exhibited more mature ligament structure and enhanced ligament-bone healing post-reconstructive surgery at 4 and 12weeks, as compared with the control group. In addition, the ETEL group was demonstrated to have higher modulus and stiffness than the control group significantly at 12weeks post-reconstructive surgery. In conclusion, our results demonstrated that the ETEL can provide sufficient vascularity and cellularity during the early stages of healing, and subsequently promote ACL regeneration and ligament-bone healing, suggesting its clinic use as a promising therapeutic modality.
  
  
  
  Early inflammatory cell infiltration, tissue and vessels ingrowth were significantly higher in the extra-articular implanted scaffolds than theses in the joint cavity. By mimicking the early stages of wound repair, which provided extra-articular inflammatory stimulation to facilitate the early ingrowth of blood vessels and cells, a vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was constructed by subcutaneous implantation for 2weeks. The fully vascularized TE ligament was then transferred to rebuild ACL without blood perfusion interruption, and was demonstrated to exhibit improved ACL regeneration, bone tunnel healing and mechanical properties.
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jisheng
authors.initials: J
authors.lastname: Ran
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Yejun
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Le
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Yangwu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Zefeng
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; China Orthopaedic Regenerative Medicine (CORMed), Hangzhou, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Zi
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Ruijian
authors.initials: R
authors.lastname: Yan
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Zhangchu
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Chenqi
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jiayun
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Yanjia
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Langhai
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Shengjun
authors.initials: S
authors.lastname: Qian
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Endodontology, Faculty of Dentistry, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Boon Chin
authors.initials: BC
authors.lastname: Heng
authors.affiliation: Laboratory of Biomechanical Orthopedics, EPFL, Lausanne, Switzerland.
authors.forename: Pioletti
authors.initials: P
authors.lastname: Dominique
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Weishan
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Lidong
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Orthopedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Orthopaedics Research Institute of Zhejiang University, Hangzhou, People's Republic of China; China Orthopaedic Regenerative Medicine (CORMed), Hangzhou, China. Electronic address: shenweiliang365@163.com.
authors.forename: Weiliang
authors.initials: W
authors.lastname: Shen
authors.affiliation: Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; China Orthopaedic Regenerative Medicine (CORMed), Hangzhou, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Ouyang
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000166:cytology / Q000254:growth & development / Q000637:transplantation*; D000070598:Anterior Cruciate Ligament Injuries / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation* / Q000379:methods; D021522:Bioartificial Organs; D003094:Collagen / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D010865:Pilot Projects; D011817:Rabbits; D012038:Regeneration / Q000502:physiology; D047011:Silk / Q000737:chemistry*; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods; D054457:Tissue Scaffolds; D016896:Treatment Outcome
chemical_list: D047011:Silk; D003094:Collagen
keywords: ACL regeneration; Bone tunnel healing; Ectopic tissue engineered ligament; Silk collagen scaffold