In Vivo Engineering of the Vocal Fold ECM With Injectable HA Hydrogels—Late Effects on Tissue Repair and Biomechanics in a Rabbit Model

Objectives To determine if the utilization of injectable chemically modified hyaluronan (HA) derivative at the time of intentional vocal fold resection may facilitate wound repair and preserve the unique viscoelastic properties of the extracellular matrix (ECM) and lamina propria 6 months after treatment. Study Design Prospective, controlled animal study. Methods Twelve rabbit vocal folds were biopsied bilaterally, and the left side of vocal fold was treated with Extracel, an injectable, chemically modified HA derivative, and the right side of vocal fold was injected with saline as control at the time of resection. Animals were sacrificed 6 months after biopsy and injection. Outcomes measured include transcription levels for procollagen, fibronectin, fibromodulin, transforming growth factor beta one (TGF-خ²1), HA synthase, and hyaluronidase, and tissue biomechanics—viscosity and elasticity. Results Extracel-treated vocal folds were found to have significantly less fibrosis than saline-treated controls. Extracel-treated vocal folds had significantly improved biomechanical properties of elasticity and viscosity. Significantly decreased levels of fibronectin, fibromodulin, TGF-خ²1, procollagen I, and HA synthase were measured. Conclusions Prophylactic in vivo manipulation of the ECM with an injectable HA hydrogel appears to induce vocal fold tissue regeneration to yield improved tissue composition and biomechanical properties at 6 months.