Shear Conditioning of Tissue-Engineered Vein Grafts Seeded with Adipose-Derived Stem Cells
Recent advances in the treatment of congenital heart defects and other cardiovascular diseases have had success using graft implantations. However, common sources in use for congenital defects remain static and require replacement with larger grafts as the patient grows. To counter this dilemma, the Tranquillo lab has been developing dynamic, tissue-engineered, acellular conduit grafts. According to Syedain et al., the process uses “entrapped dermal fibroblasts” (p. 2) to remodel a fibrin matrix to mimic arterial appearance and properties; moreover, after implantation, host cells will move into and integrate the conduit into the surrounding vessels, allowing for growth with the patient (p. 2). La and Tranquillo seeded adipose-derived stem cells (ASC) onto graft cross-sections and exposed both to shear stresses in a parallel-plate flow chamber (PPFC), which successfully encouraged differentiation toward an endothelial phenotype (p. 1243, 1246-1248). My UROP project involved prototyping and initial testing of technology to assist the shear conditioning of the graft. A pump control system was set up using a custom-designed PCB and feedback loop using an Arduino Due and C++ programming to ensure desired flow rates. Further, a seeding and shear conditioning chamber was designed, and prototypes were manufactured and used in an experiment. The results of the experiment showed the success of the chamber and provided information for further development for ease of use.