Establishing principles of macromolecular crowding for in vitro fibrosis research of the vocal fold lamina propria

Objectives/hypothesis: Vocal fold fibrosis represents a major disease burden. Screening of antifibrotic compounds could be facilitated by an in vitro fibrogenesis system. Limitations of existing models might be overcome by implication of the excluded volume effect.

Study design: In-vitro study.

Methods: Vocal fold fibroblasts obtained from rats' lamina propria were cultured in four different settings: in standard medium, under "crowded" conditions by adding inert macromolecules, under external administration of transforming growth factor (TGF)ß-1, and under a combination of both. After 5 days, supernatant and cell layer were collected and analyzed by enzyme-linked immunosorbent assay. Immunofluorescence was additionally performed.

Results: Collagen-alpha1(I) deposition increased significantly under crowded conditions and after administration of TGFβ-1. Amounts of collagen in the cell layer were significantly higher under crowding conditions with TGFβ-1 compared to administration of TGFβ-1 alone.

Conclusion: Crowding enhanced collagen deposition, resulting in more favorable conditions for studying fibrogenesis. This can be the first step toward developing a robust in vitro model for testing antifibrotic compounds.

Level of evidence: NA.