Meta-analysis of in vitro methods on tracheal decellularization

Introduction: Tracheal decellularization is one of the main processes to provide tracheal substitutes for tracheal replacement. Recently, studies have been held for agents and combinations of processes for tracheal decellularization with different outcomes. This study aimed to evaluate the efficacy of tracheal decellularization by the immunogenic cellular elements using residual deoxyribonucleic acid (DNA) contents (ng/mg) and the preservation of biomechanical integrity by glycosaminoglycan (GAG) content (μg/mg), modulus tensile strength (MPa), ultimate tensile strength (MPa), and stress loading of 50% deformation (N). Methods: We conducted a meta-analysis based on PRISMA criteria. Data from experimental studies in MEDLINE, Scopus, and ScienceDirect from inception to August 21, 2023, were sought and computed using RevMan 5.4. The outcomes of tracheal decellularization were evaluated through effect size estimates based on pooled Standardized Mean Difference (SMD) with 95% CI. Results: Tracheal decellularization has significantly reduced the DNA and GAG content after the process (SMD: −11.77, 95% CI [−13.92, −8.62], p < 0.00001; SMD: −6.70, 95% CI [−9.55, −3.85], p < 0.00001). No significant outcomes were observed in modulus and ultimate tensile strength result (SMD: −0.14, 95% CI [−0.64, 0.36], p = 0.58; SMD: 0.11, 95% CI [−0.57, 0.80], p = 0.75). The stress loading of 50% deformation was observed to significantly lower (SMD: −1.61, 95% CI [−2.49, −0.72], p = 0.0004). Conclusion: Tracheal decellularization has been proven to effectively remove immunogenic cells. However, extracellular matrix integrity and biomechanical properties vary among different decellularization techniques, indicating a need for further refinement to achieve better preservation.