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Mechanical properties and structure–function relationships in articular cartilage repaired using IGF‐I gene‐enhanced chondrocytes
Author(s) -
Griffin Darvin J.,
Ortved Kyla F.,
Nixon Alan J.,
Bonassar Lawrence J.
Publication year - 2016
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.23038
Subject(s) - chondrocyte , cartilage , fibrin , genetic enhancement , aggregate modulus , biomedical engineering , osteoarthritis , transplantation , medicine , chemistry , microbiology and biotechnology , anatomy , gene , surgery , pathology , biology , immunology , biochemistry , alternative medicine , organic chemistry , dynamic mechanical analysis , dynamic modulus , polymer
Several studies have demonstrated the benefits of IGF‐I gene therapy in enhancing the histologic and biochemical content of cartilage repaired by chondrocyte transplantation. However, there is little to no data on the mechanical performance of IGF‐I augmented cartilage grafts. This study evaluated the compressive properties of full‐thickness chondral defects in the equine femur repaired with and without IGF‐I gene therapy. Animals were randomly assigned to one of three study cohorts based on chondrocyte treatment provided in each defect: (i) IGF‐I gene delivered by recombinant adeno‐associated virus (rAAV)‐5; (ii) AAV‐5 delivering GFP as a reporter; (iii) naïve cells without virus. In each case, the opposite limb was implanted with a fibrin carrier without cells. Samples were prepared for confined compression testing to measure the aggregate modulus and hydraulic permeability. All treatment groups, regardless of cell content or transduction, had mechanical properties inferior to native cartilage. Overexpression of IGF‐I increased modulus and lowered permeability relative to other treatments. Investigation of structure–property relationships revealed that Ha and k were linearly correlated with GAG content but logarithmically correlated with collagen content. This provides evidence that IGF‐I gene therapy can improve healing of articular cartilage and can greatly increase the mechanical properties of repaired grafts. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:149–153, 2016.