(0668) Investigating Fibroblast Heterogeneity Following Airway Reconstruction

Introduction: Restenosis is a common complication following airway reconstruction, characterized by increased collagen and fibroblast recruitment. Fibroblasts are a heterogeneous population, with one part of this population being activated (CTHRC1+) fibroblasts. Using a mouse microsurgical model, we aim to investigate the recruitment of the activated fibroblast subtype and its proliferation following airway reconstruction.

Methods: Tracheal segments were harvested and implanted into genetically identical C57BL/6 mice. Native tracheal tissue (n = 4) and syngeneic tracheal grafts 2 weeks post-surgery (n = 4) were processed for staining. Immunofluorescence staining was performed to visualize activated (CTHRC1+, Vimentin +) and proliferating (Ki67+, CTHRC1+, Vimentin +) fibroblasts. Fibroblast quantification was performed within the full graft, excluding cells in the epithelium and cartilage rings. Quantification for native trachea was performed within the length of 3 cartilage rings, accounting for the average number of cartilages across the fullgraft.

Results: Histological analysis showed markedly higher (p < 0.0001) activated fibroblasts at 2 weeks post-surgery. Activated fibroblasts composed 67.5% of the total fibroblast population for the surgical group, while only 27.8% of fibroblasts were activated in the native trachea. Of the activated fibroblast subpopulation, 19.3% were proliferating in the surgical group. This was significantly more (p = 0.0191) than the native trachea group, of which only 8.7% of activated fibroblasts were proliferating.

Conclusions: Airway reconstruction results in increased recruitment and proliferation of activated fibroblasts. Further studies may explore the collagen production of activated fibroblasts, elucidating their role in the development of restenosis and aiding the development of targeted therapies.