NMR Assessment of Me2SO in Decellularized Cryopreserved Aortic Valve Conduits

IntroductionDecellularized cryopreserved allograft vascular tissue may provide a nonimmunogenic scaffold that is suitable for repopulation by cells from a variety of sources, conferring the potential for growth and repair. Although dimethyl sulfoxide (Me2SO) is generally regarded as a safe cryoprotectant, even low levels may alter function of repopulating cells. We investigated the residual concentration of Me2SO in the aqueous compartment of cryopreserved ovine aortic valve conduits following decellularization.Materials and methodsAortic valve conduits from Suffolk sheep were cryopreserved in 1.1M (7.5% vol/vol) Me2SO according to the protocol of our local tissue bank. Three aortic valve conduits were decellularized in a series of hypotonic and hypertonic Tris buffers. Tissue samples were taken at regular time intervals throughout the decellularization process and equilibrated in double distilled, deionized H2O for 28 days. Quantitative proton nuclear magnetic resonance spectroscopy was used to determine the residual Me2SO concentration in the equilibration solutions from which Me2SO tissue concentrations were calculated.ResultsAfter thawing, the mean Me2SO concentration in the valve conduit was 0.302 ± 0.081 M. The decellularization process resulted in a stepwise reduction in the Me2SO concentration to less than 8.56 × 10−5 ± 9 × 10−5 M (P = 0.02). The diffusion coefficient was 2.5 × 10−6 cm2/s.ConclusionsOur study demonstrates that Me2SO is effectively washed out of the aortic valve conduit during decellularization, resulting in a final concentration that is several orders of magnitude less than Me2SO concentrations reported to alter cell function.