Collagen hollow structure for bladder tissue engineering.

Bladder is affected by numerous pathologies which require augmentation or replacement of the organ. Currently, the gold standard is enterocystoplasty which causes many complications. Bioengineering techniques propose options to overcome these issues. The innovative and very simple tissue engineered three-dimensional spherical bladder model reported here mimics the bladder natural shape using collagen-derived scaffold. Bladder mesenchymal cells were embedded inside the scaffold and epithelial cells seeded at its surface. Therefore, the bladder mesenchymal and urothelial cells seeded in the model were subjected to tensions similar to what is found in the native tissue. Both cell types organize themselves simultaneously within a culture period of 15 days. Our spherical model was able to demonstrate characteristics of highly advanced urothelial maturity. Hematoxylin eosin staining, the uroplakins immunodetection and electron microscopy analysis showed the impressive degree of urothelial organization. In addition, collagen remodeling was observed and smooth muscle cells, expressing myosin, presented a tendency to realign parallel to the luminal surface. With properties comparable to native tissue, our three-dimensional spherical bladder model could offer the possibility to produce tissue-engineered bladder implants. This technique could be efficient for partial replacement of pathologic bladder sites.