In vitro evaluation of acellular porcine urinary bladder extracellular matrix - A potential scaffold in tissue engineered skin

Current tissue engineered skin substitutes employ a cellular scaffold, typically a collagen biopolymer to support the transfer of cells to the wound bed. These scaffolds however, exhibit poor approximation of epidermal-dermal histogenesis and delayed vascularisation upon implantation in vivo. In this study we evaluate a novel decellularised extracellular matrix (ECM) scaffold derived from the porcine urinary bladder wall; termed urinary bladder matrix (UBM). ECM scaffolds possess intrinsic angiogenic properties in the form of functional proteins and potent angiogenic growth factors. They have repeatedly demonstrated rapid angiogenesis and constructive remodelling in clinical trials. UBM is notable for containing an epithelial basement membrane, which offers improved approximation of epidermal-dermal histogenesis. In this study human dermal fibroblasts were seeded on UBM constructs in vitro. UBM ultrastructure was assessed using scanning electron microscopy and histology sections. Cell/scaffold interactions were examined, including cellular adhesion, proliferation, migration and protein synthesis using quantitative indicators. Cell morphology was determined using scanning electron microscopy. The study demonstrated that UBM supported the viability of human dermal fibroblasts. Cells displayed uninhibited proliferation and collagen synthesis was supported. Histological analysis showed the cells had organised spatially via the basement membrane. Cells grown on the basement membrane surface formed a monolayer while those grown on the opposite abluminal surface penetrated the scaffold. A high degree of cellular attachment was observed on the luminal and abluminal surfaces, 93.068 ± 2.3% and 92.045. ± 4.3%, respectively with no significant difference between the two surfaces (P= 0.121, n= 3). This study demonstrates that UBM fulfils the fundamental properties for scaffold design and is a promising novel scaffold for future skin tissue engineering efforts.