Dynamic flow for efficient partial decellularization of tracheal grafts: A preliminary rabbit study

Objective: Bioengineered tracheal grafts are a potential solution for the repair of long-segment tracheal defects. A recent advancement is partially decellularized tracheal grafts (PDTGs) which enable regeneration of host epithelium and retain viable donor chondrocytes for hypothesized benefits to mechanical properties. We propose a novel and tunable 3D-printed bioreactor for creating large animal PDTG that brings this technology closer to the bedside.

Methods: Conventional agitated immersion with surfactant and enzymatic activity was used to partially decellularize New Zealand white rabbit (Oryctolagus cuniculus) tracheal segments (n = 3). In parallel, tracheal segments (n = 3) were decellularized in the bioreactor with continuous extraluminal flow of medium and alternating intraluminal flow of surfactant and medium. Unprocessed tracheal segments (n = 3) were also collected as a control. The grafts were assessed using the H&E stain, tissue DNA content, live/dead assay, Masson's trichrome stain, and mechanical testing.

Results: Conventional processing required 10 h to achieve decellularization of the epithelium and submucosa with poor chondrocyte viability and mechanical strength. Using the bioreactor reduced processing time by 6 h and resulted in chondrocyte viability and mechanical strength similar to that of native trachea.

Conclusion: Large animal PDTG created using our novel 3D printed bioreactor is a promising approach to efficiently produce tracheal grafts. The bioreactor offers flexibility and adjustability favorable to creating PDTG for clinical research and use. Future research includes optimizing flow conditions and transplantation to assess post-implant regeneration and mechanical properties.

Level of evidence: NA.