A three dimensional scaffold for single staged tissue engineering

Study I Aims: Evaluate a collagen-PCL scaffold with minced bladder mucosa in vitro. M&M: Minced tissue was cultured on top of the scaffold. Scaffold properties were evaluated. Results: Good proliferation. Multilayered epithelium after 4 weeks. High tensile strength. Conclusions: Transplant with favorable properties for reconstruction of urogenital tract in one single-staged surgery. Study II Aims: Evaluate a collage-PLGA scaffold with minced bladder mucosa in vitro. M&M: Minced tissue was cultured on top and inside the scaffold. Scaffold properties were evaluated. Results: Good proliferation. Multilayered epithelium after 4 weeks. High tensile strength. Conclusions: Transplant with favorable properties for reconstruction of urogenital tract in one single-staged surgery. Study III Aims: Evaluate differentiation of bone marrow MSCs into urothelium, separately or on top of a collagen-PCL scaffold. M&M: MSCs were co-cultured with urothelium or cultured with conditioned medium. MSCs were also differentiated on the scaffold. Results: MSCs differentiated into urothelial-like cells after 14 days with both methods, and on top of the collagen-PCL scaffold. Conclusions: In the future, autologous bone marrow MSCs may be a source for urogenital regenerative medicine in cases with lack of native urothelial cells. Study IV Aim: Evaluate a collagen-PCL scaffold with minced skin in a rat model. M&M: Minced skin was cultured on top of a collagen-PCL scaffold in vitro and in vivo, in a subcutaneous rat model. Scaffold properties were evaluated. Results: Good integration of scaffold. Keratinocyte proliferation on top of the scaffold that kept its tensile strength and elasticity. Conclusions: Cell expansion on top of the scaffold could take place after transplantation in vivo. This may facilitate future urogenital reconstruction and autologous tissue expansion without in vitro cell culturing

Exploring the Concept of In Vivo Guided Tissue Engineering by a Single-Stage Surgical Procedure in a Rodent Model

In severe malformations with a lack of native tissues, treatment options are limited. We aimed at expanding tissue in vivo using the body as a bioreactor and developing a sustainable single-staged procedure for autologous tissue reconstruction in malformation surgery. Autologous micro-epithelium from skin was integrated with plastically compressed collagen and a degradable knitted fabric mesh. Sixty-three scaffolds were implanted in nine rats for histological and mechanical analyses, up to 4 weeks after transplantation. Tissue integration, cell expansion, proliferation, inflammation, strength, and elasticity were evaluated over time in vivo and validated in vitro in a bladder wound healing model. After 5 days in vivo, we observed keratinocyte proliferation on top of the transplant, remodeling of the collagen, and neovascularization within the transplant. At 4 weeks, all transplants were fully integrated with the surrounding tissue. Tensile strength and elasticity were retained during the whole study period. In the in vitro models, a multilayered epithelium covered the defect after 4 weeks. Autologous micro-epithelial transplants allowed for cell expansion and reorganization in vivo without conventional pre-operative in vitro cell propagation. The method was easy to perform and did not require handling outside the operating theater