Dynamic Flow Priming Programs Allow Tuning Up The Cell Layers Properties for Engineered Vascular Graft.

Tissue engineered vascular graft (TEVG) has a good potential to replace and repair demanded blood vessels. Here, we proposed a novel method to create three-layered TEVG on biocompatible glass fiber scaffolds starting from flat sheet state into tubular shape and to train the resulting tissue by our developed bioreactor system. Constructed tubular tissues were matured and trained under 3 types of individual flow programs, and their mechanical and biological properties were analyzed. The strength of scaffold after cell seeding was 2.83 N which is sufficient to withstand the pressure of blood flow and the use of sutures. Fluorescent imaging and histological examination of trained vascular tissue revealed that each cell layer has its own individual response to training flow rates. Fluid flow simulation model was created based on experimentally measured tissue geometries; its analysis suggested a correlation between local flow rate fluctuations and fibroblast layer infiltration depth into the scaffold. Concluding: a three-layered tissue structure similar to natural can be created by seeding different cell types in succession, and the following training of the forming tissue with increasing flow by a bioreactor is effective for promoting cell survival, and cell layer formation of desired geometry.