Comparison of biomechanical properties of bile duct between pigs and humans for liver xenotransplant

Background. Pigs have been regarded as the preferred source of organs for human xenotransplantation. The aim of the present study was to explore the biomechanical properties of the bile duct in pigs and humans to provide evidence for liver xenotransplantation. Materials and methods. Fresh bile duct specimens obtained from 50 pigs aged 3 to 12 months and five deceased human donors. The diameters and wall thickness of the bile duct were measured using a computer imaging analysis system. The pressure-diameter of bile ducts was tested with biomechanical equipment. The corresponding parameters were calculated: incremental elastic moduli (E-inc), pressure-strain elastic modulus (E-p), volume elastic modulus (E-v), and compliance. Results. The E-inc, E-p, and E-v of porcine bile duct gradually decreases with age. However, the E-inc, E-p, and E-v gradually increased after pigs aged 10 months. The E-inc, E-p, and E-v of pig bile ducts aged 3 to 6, and 11 to 12 months were higher than that of humans aged 20 to 40 years (P < .01). The changes in compliance of the porcine bile duct with age oppose those in elastic modulus. There were no significant differences in the elastic modulus and compliance of the bile duct between pigs aged 7 to 10 months and adult humans (P > .05). Conclusions. The biomechanical properties of the bile duct of pigs aged 7 to 10 months match that of adult humans. The correlation between age and biomechanical properties of bile ducts in pigs implied that a pig aged 7 to 10 months should be chosen for pig-to-human liver xenotransplantation.