Injection of vocal fold lamina propria-derived hydrogels modulates fibrosis in injured vocal folds

Vocal fold (VF) fibrosis, often resulting from phonosurgery, radiation, or trauma, causes irreversible voice dysfunction due to excessive ECM deposition and increased tissue stiffness. No FDA-approved treatments for VF fibrosis exist, highlighting the need for novel antifibrotic therapies. TGF-β1 contributes to fibroblast-to-myofibroblast activation, leading to increased ACTA2 expression and collagen production via SMAD3, YAP1, and integrin signaling pathways. Leveraging the principle that local cells respond to tissue-specific signals, our ECM hydrogel, derived from decellularized vocal fold lamina propria (VFLP-ECM), reduced ACTA2 expression in TGF-β1-stimulated VF fibroblasts, showcasing antifibrotic potential. This study evaluates the therapeutic potential of VFLP-ECM hydrogel in a rabbit VF injury model. VFLP-ECM hydrogel or bovine type I collagen injections were administered 7 days post-injury and evaluated on day 28. We compared two VFLP-ECM formulations: a manual process (VFLP (man)) and an accelerated automated method (VFLP (au)). VFLP (man) modulated fibrosis-associated gene expressions more effectively than controls. Proteomics identified 229 proteins uniquely preserved in VFLP (man), including vitronectin, crucial in TGF-β1 signaling and ECM remodeling. Transcriptomic analysis suggests downregulation of fibrotic markers and inhibition of SMAD3, YAP1, and MRTFA, alongside upregulation of SMAD7, an inhibitor of TGF-β signaling. Notably, VFLP (man) treatment recovered stiffness comparable to uninjured controls (1.84 vs. 1.94 mN), whereas collagen-treated tissues remained stiff (2.7 mN), similar to the injury group (2.6 mN), indicating incomplete mechanical recovery. These in vivo data show that manually decellularized VFLP-ECM hydrogel attenuates fibrosis by disrupting key biochemical and mechanical cues driving myofibroblast activation.