The engineered bladder patch with a three-layer structure promotes the regeneration and functional recovery of the bladder in a rabbit model.

The engineered bladder patch with a three-layer structure was constructed from a bi-layer silk fibroin scaffold (BSFS) and a methacrylated bladder acellular matrix hydrogel (BAMMAH) that carried induced vascular endothelial cells (VECs) and induced nerve cells (NCs). The patch was developed for bladder augmentation in a rabbit model. The prepared BSFS combined the rigidity of silk fibroin film with the elasticity of silk fibroin sponge, providing a support framework for the construction of engineered bladder. The synthesized BAMMAH exhibited a rapid gelling property, and 2% BAMMAH showed good rheological properties and an internal pore structure. Immunofluorescent staining and RT-qPCR confirmed that the induction schemes for adipose-derived mesenchymal stem cells (ADSCs) differentiation into VECs and NCs were feasible and stable. Immunofluorescence analysis demonstrated that incubation with omentum could promote the regeneration of the vascular network inside the engineered patch with a three-layer structure (BSFS-BAMMAH-ADSCs-VECs-NCs). Animal experimental data showed that the engineered patch could promote the regeneration of the bladder wall and the recovery of bladder function. These results confirmed that the constructed engineered bladder patch with a three-layer structure could regenerate the blood vessel network and neural reinnervation, providing a feasible method to solve the difficulties of vascular network and neural innervation in bladder tissue engineering research.