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BACKGROUND: Engineered tissues are an exciting potential source of small diameter vascular grafts due to limited supply and patency of available alternatives. Engineered tissue vascular grafts (ETVGs) will provide physiological function that resembles native arteries and maintain the required mechanical properties as they integrate with host tissue. Mechanical stimulation during incubation encourages proper cell alignment and increases extracellular matrix deposition. The enhanced organization of the engineered tissue leads to improved compliance over synthetic alternatives without sacrificing strength and may lead to better integration in vivo.
METHODS: We have developed a bioreactor that mechanically trains grafts during incubation. To test the seeding efficiency of the bioreactor, rat vascular smooth muscle cells (VSMC) were seeded onto electrospun PCL scaffolds by perfusion at various cell concentrations then incubated Page | 15 for 1 week under static conditions. We assessed gross morphology with H&E; collagen with picrosirius red; and VSMC density with DAPI. ETVGs were further evaluated with mechanical testing and scanning electron microscopy to evaluate mechanical and microstructural properties.
RESULTS: Cells were successfully seeded evenly onto the luminal surface of electrospun PCL scaffolds. Cells remained viable and continued to proliferate and deposit ECM throughout incubation.
CONCLUSIONS: Progress in the ETVG paradigm requires a systematic approach toward better understanding of the cause-effect interplay between implant properties, host reactions, and their modulation with controllable parameters. Future directions involve the assessment of the effects of mechanical training on growth and remodeling of engineered tissues in vitro and subsequent effects on the foreign body response post-implantation in a murine model.
Mechanical Engineering | Nuclear Engineering
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