title: Morphological and functional characteristics of three-dimensional engineered bone-ligament-bone constructs following implantation.
abstract: The incidence of ligament injury has recently been estimated at 400,000/year. The preferred treatment is reconstruction using an allograft, but outcomes are limited by donor availability, biomechanical incompatibility, and immune rejection. The creation of an engineered ligament in vitro solely from patient bone marrow stromal cells (has the potential to greatly enhance outcomes in knee reconstructions. Our laboratory has developed a scaffoldless method to engineer three-dimensional (3D) ligament and bone constructs from rat bone marrow stem cells in vitro. Coculture of these two engineered constructs results in a 3D bone-ligament-bone (BLB) construct with viable entheses, which was successfully used for medial collateral ligament (MCL) replacement in a rat model. 1 month and 2 month implantations were applied to the engineered BLBs. Implantation of 3D BLBs in a MCL replacement application demonstrated that our in vitro engineered tissues grew and remodeled quickly in vivo to an advanced phenotype and partially restored function of the knee. The explanted 3D BLB ligament region stained positively for type I collagen and elastin and was well vascularized after 1 and 2 months in vivo. Tangent moduli of the ligament portion of the 3D BLB 1 month explants increased by a factor of 2.4 over in vitro controls, to a value equivalent to those observed in 14-day-old neonatal rat MCLs. The 3D BLB 1 month explants also exhibited a functionally graded response that closely matched native MCL inhomogeneity, indicating the constructs functionally adapted in vivo.
authors.affiliation: Department of Mechanical Engineering, University of Michigan, Ann Arbor, 48109, USA.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Ma
authors.forename: Kristen
authors.initials: K
authors.lastname: Goble
authors.forename: Michael
authors.initials: M
authors.lastname: Smietana
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kostrominova
authors.forename: Lisa
authors.initials: L
authors.lastname: Larkin
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Arruda
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001696:Biomechanical Phenomena; D001854:Bone Marrow Cells / Q000166:cytology*; D001842:Bone and Bones / Q000098:blood supply / Q000166:cytology*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D018920:Coculture Techniques; D024042:Collagen Type I / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004549:Elastin / Q000378:metabolism; D005260:Female; D005269:Femur / Q000166:cytology; D019793:Fluorescein / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006651:Histocytochemistry; D007150:Immunohistochemistry; D007211:Indoles / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008022:Ligaments / Q000098:blood supply / Q000166:cytology*; D051381:Rats; D011916:Rats, Inbred F344; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D014182:Transplantation, Autologous
chemical_list: D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D003470:Culture Media; D005456:Fluorescent Dyes; D007211:Indoles; D037102:Lectins; C007293:DAPI; D004549:Elastin; D019793:Fluorescein