Engineering a functional ACL reconstruction graft containing a triphasic enthesis-like structure in bone tunnel for the enhancement of graft-to-bone integration

• DOI: 10.1016/j.jot.2024.01.004
• Publication Date: 2024-03-22T11:43:03Z
• Authors: Qiang Shi; Yang Chen; Yan Xu; Can Chen; Hongbin Lu
• Keywords: Enthesis

Anterior cruciate ligament (ACL) rupture is a common sports injury, which causes knee instability and abnormal joint kinematics. The current ACL graft was single-phasic, not convenient for the formation of enthesis-like tissue in bone tunnel, resulting poor integration graft-to-bone. A band-shaped acellular tendon (BAT) prepared as core component reconstruction at first, while sleeve-shaped cartilage (SAC) or (SAB) fabricated using vacuum aspiration system (VAS)-based decellularization protocol. biocompatibility three matrixes evaluated. Furthermore, collagen-binding peptide (CBP) derived from A3 domain von Willebrand factor respectively fused into N-terminal GDF7, TGFβ3, BMP2 to synthesize recombinant growth factors capable binding collagen (named C-GDF7, C-TGFβ3, C-BMP2), were tethered BAT, SAC SAB improving their inducibilities stem cell differentiation. An in-vitro experiment performed evaluate theirs osteogenic, chondrogenic, tenogenic inducibilities. Then, C-TGFβ3-tethering (C-TGFβ3@SAC) C-BMP2-tethering (C-BMP2@SAB) sequentially surrounded tunnel part C-GDF7-tethering BAT (C-GDF7@BAT), thus with triphasic structure tissue-engineered graft, TE graft) engineered. Lastly, canine model used in-vivo performance this enhancing graft-to-bone integration. SAC, well preserved components native tendon, cartilage, bone, showing good biocompatibility. C-BMP2 showed stronger ability SAB. C-GDF7@BAT, C-TGFβ3@SAC, C-BMP2@SAB controlled delivery scaffold-specific release BMP2, superior tenogenic, osteogenic inducibility, respectively. Using model, abundant newly-formed connective fibers could be observed site between postoperative 16 weeks. Meanwhile, failure load reconstructed by significantly higher than that autograft. reconstruct ruptured augment integration, demonstrating high potential clinical translation reconstruction. findings study indicated novel may provide foundation future application.