Extracellular matrices as advanced scaffolds for vascular tissue engineering.

An alternative non-vascular extracellular material was obtained by decellularisation of porcine urinary bladder and examined for its potential as scaffold for vascular tissue engineering. Analysis using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Laser Scanning Microscopy (LSCM) showed a porous interconnective microarchitecture, an abundance of well preserved fibers on the abluminal side and a micropatterned flat luminal surface. Uniaxial tensile testing revealed a strength of 1.9+/-0.3 MPa for the rehydrated material in a phosphate buffered saline medium for the ECM-UBM sheet and these results comparable to those of native artery of a middle aged human. Multilamination of the UBM increases the tensile properties in general (9+/-0.45 MPa for 2 layer, 30+/-0.6 MPa for 4 layers construct), with no effect on elongation capacities (38-40%) of the material. Contact-angle measurements indicated that the ECM-UBM surface exhibited a hydrophylic characteristic and better wettability than any vascular synthetic materials. Comparison of the initial adhesion in the multiplayer ECM constructs was evaluated and was found not to be altered by the preparation. The HAECs and HSMC shown an excellent adherence, spread and proliferation on the ECM-UBM material with the preservation of the cell phenotype. The level of MMP-1 and MMP-9 produced by endothelial cells was evaluated in this study and provides some data on the remodelling capacity of the scaffold. Vascular cell seeded-UBM constructs may also provide a suitable and affordable in vitro model for cell-physiology and drug development studies, which may elucidate to the mechanisms of vascular disease formation, and its prevention and treatment.