Regional biomechanical and histological characterisation of the passive porcine urinary bladder: Implications for augmentation and tissue engineering strategies

The aim of this study was to identify and quantify potential regional and directional variations in the quasistatic uniaxial mechanical properties of the passive urinary bladder wall. Overall, the lower body and trigone regions demonstrated the highest degree of directional anisotropy, whereas the ventral region demonstrated the least directional anisotropy. Significant regional anisotropy was found only along the apex-to-base direction. The dorsal and ventral regions demonstrated a significantly increased distensibility along the apex-to-base direction compared to the other bladder regions, whereas the trigone and lower body regions demonstrated the least distensibility. The trigone, lower body and lateral regions also demonstrated the highest tensile strength both at regional and directional levels. The study detected significant regional and directional anisotropy in the mechanical properties of the bladder and correlated this anisotropy to the distended and non-distended tissue histioarchitecture and whole organ mechanics. By elucidating the inhomogeneous nature of the bladder, the results from this study will aid the regional differentiation of bladder treatments in terms of partial bladder replacement with suitable natural or synthetic biomaterials, as well as the development of more realistic constitutive models of bladder wall biomechanics and improved computational simulations to predict deformations in the natural and augmented bladder.