Porcine extracellular matrix scaffolds in reconstructive urology: An ex vivo comparative study of their biomechanical properties

Functional reconstruction of the human urinary bladder has been attempted by replacing defective bladder tissue with tissue-engineered xenogenic extracellular matrix (ECM) scaffolds. However, experimental studies that demonstrate the effects of implanted ECMs on important biomechanical properties such as total bladder capacity (TBC) and compliance ( C ) are lacking. In the current study, the effects of ECM scaffold surface area (SA) on TBC and C was assessed, ex vivo, in an ovine model ( n = 5 ). TBC and C were measured at pressures ( P ) of 5, 10, 15 and 20 mm Hg prior to performing a 3×3 cm (9 cm2) partial cystectomy defect. Equal-sized 3×3 cm (9 cm2) and larger 6×6 cm (36 cm2) urinary bladder matrix (UBM) scaffolds of porcine origin replaced the 3×3 cm cystectomy defect, and TBC and C were re-recorded for comparative analysis. The results showed that TBC decreased by 39.6%±0.005% (122.9 ml±15 ml, p < 0.05 ) and C by 38.9%±0.51%, ( Δ P = 0 – 5 mm Hg , p < 0.05 ) in ovine bladders reconstructed with 3×3 cm UBM scaffolds compared to their native values. It was also found that TBC increased by 25.6±0.64% (64.2 ml ± 8.8 ml, p > 0.05 ) and C by 24.5±0.43% ( Δ P = 0 – 5 mm Hg , p > 0.05 ) in the 6×6 cm UBM scaffold group compared to the 3×3 cm UBM scaffold group; however, these values were not statistically significant. The present work demonstrates that a fourfold increase in ECM scaffold SA relative to its intended defect does not lead to a significant improvement in TBC and C values.