The Use of a Dehydrated Cellularized Collagen Matrix to Replace Fibrotic Vocal Fold Mucosa

Objectives: Fibrosis of the vocal fold lamina propria reduces vocal cord vibration resulting in a chronically hoarse voice. We describe a novel approach using umbilical cord-derived mesenchymal stem cells in a dehydrated collagen matrix (cellogen) to reconstruct the delicate balance of extracellular matrix within the vocal fold lamina propria whilst limiting the host inflammatory response to the implant. Methods: Human umbilical cord-derived mesenchymal stem-cells were embedded in bovine type I collagen hydrogel and dehydrated using the RAFT (TM) 3D culture system. The extracellular matrix, cellular viability and composition, paracrine profile, and genomic profile were assessed and the scaffold engrafted onto the hind muscle of NUDE mice. Results: The cells retained stem-cell markers following fabrication and secreted collagen III, fibronectin, and glycosaminoglycans within the scaffold. Electron microscopy showed the scaffold consisted of single strands of protein with interspersed bundles of a similar size to native vocal fold lamina propria. The use of the dehydration step improved cell viability and upregulated the expression of genes important in wound healing and matrix organization compared with unmodified collagen hydrogel carriers. The cells were shown to secrete exosomes and cytokines and, following engraftment within an immuno-compromised mouse model, appeared to modulate the host inflammatory response compared with controls. Conclusion: This article provides a scalable cell-protein scaffold that with further modifications could provide a replacement for lost or damaged vocal fold mucosa. Further investigations are required to assess the mechanical properties of the scaffold and inhibit the differentiation of the umbilical cord-derived stem-cells following implantation.