VEGF functionalization of suture tape results in decreased graft inflammatory and catabolic response in a rabbit model of ACL reconstruction

Introduction: Improving ligament reconstruction biology may potentially be achieved through capturing autologous circulating factors such as vascular endothelial growth factor (VEGF) using commercially available biomaterials. Objectives: To evaluate anterior cruciate ligament reconstruction (ACLR) using a VEGF functionalized suture tape in a rabbit model of ACLR with a semitendinosus autograft. Methods: VEGF-binding peptides were covalently bonded to polyethylene suture tape (ST) to generate functionalized constructs. Forty-six female New Zealand white rabbit ACLs were reconstructed with semitendinosus hamstring autograft (n = 6), hamstring + ST (n = 16), hamstring + scrambled peptide ST (n = 17), and hamstring + VEGF-functionalized ST (n = 17). Healing was evaluated at 2to 4 weeks using PCR, RNA sequencing, micro CT, histology, and biomechanical testing. Results: All rabbits successfully underwent ACLR, with no adverse events. ACLR with VEGF ST demonstrated significant decreases in inflammatory response (CD14, CD163), catabolism (MMP1, MMP3), and apoptosis (TNFSF10, Caspase-10) markers as compared to nonfunctionalized ST (P ≤ .04). µCT demonstrated similar bone tunnel mineral density in hamstring + VEGF ST rabbits as compared to hamstring + scrambled ST controls (P ≥ .31). Histology and biomechanical testing similarly demonstrated no adverse effects of VEGF-based immunomodulation on the tendon grafts. Conclusions: Using a rabbit model, ACLR performed with VEGF-functionalized suture tape demonstrated significantly decreased markers of inflammation, catabolism, and apoptosis as compared to ACLR with nonfunctionalized suture tape. No adverse effects of functionalization were noted. Future studies should further investigate the utility of functionalized suture tape in ACLR.