title: Oscillatory shear stress created by fluid pulsatility versus flexed specimen configurations.
abstract: Oscillatory shear stress (OSS), caused by time-varying flow environments, may play a critical role in the production of engineered tissue by bone marrow-derived stem cells. This is particularly relevant in heart valve tissue engineering (HVTE), owing to the intense haemodynamic environments that surround native valves. In this study, we examined and quantified the role that (i) physiologically relevant scales of pulsatility and (ii) changes in geometry as a function of specimen flexure have in creating OSS conditions. A U-shaped bioreactor capable of producing flow, stretch and flexure was modelled with housed specimens, and computational fluid dynamic simulations were performed. We found that physiologically relevant OSS can be maximised by the application of pulsatile flow to straight, non-moving specimens in a uniform manner. This finding reduces a substantial layer of complexity in dynamic HVTE protocols in which traditionally, time-varying flow has been promoted through specimen movement in custom-made bioreactors.
authors.affiliation: a Tissue Engineered Mechanics, Imaging and Materials (TEMIM) Laboratory, Department of Biomedical Engineering , Florida International University , Miami , FL , USA.
authors.forename: Manuel
authors.initials: M
authors.lastname: Salinas
authors.forename: David E
authors.initials: DE
authors.lastname: Schmidt
authors.forename: Miguel
authors.initials: M
authors.lastname: Libera
authors.forename: Richard R
authors.initials: RR
authors.lastname: Lange
authors.forename: Sharan
authors.initials: S
authors.lastname: Ramaswamy
mesh_terms: D019149:Bioreactors; D003198:Computer Simulation; D006351:Heart Valves / Q000502:physiology*; D006801:Humans; D011673:Pulsatile Flow; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods