Use of sucrose to diminish pore formation in freeze-dried heart valves

© 2018, The Author(s). Freeze-dried storage of decellularized heart valves provides easy storage and transport for clinical use. Freeze-drying without protectants, however, results in a disrupted histoarchitecture after rehydration. In this study, heart valves were incubated in solutions of various sucrose concentrations and subsequently freeze-dried. Porosity of rehydrated valves was determined from histological images. In the absence of sucrose, freeze-dried valves were shown to have pores after rehydration in the cusp, artery and muscle sections. Use of sucrose reduced pore formation in a dose-dependent manner, and pretreatment of the valves in a 40% (w/v) sucrose solution prior to freeze-drying was found to be sufficient to completely diminish pore formation. The presence of pores in freeze-dried valves was found to coincide with altered biomechanical characteristics, whereas biomechanical parameters of valves freeze-dried with enough sucrose were not significantly different from those of valves not exposed to freeze-drying. Multiphoton imaging, Fourier transform infrared spectroscopy, and differential scanning calorimetry studies revealed that matrix proteins (i.e. collagen and elastin) were not affected by freeze-drying

Toward acellular xenogeneic heart valve prostheses: histological and biomechanical characterization of decellularized and enzymatically deglycosylated porcine pulmonary heart valve matrices

The use of decellularized xenogeneic heart valves might offer a solution to overcome the issue of human valve shortage. The aim of this study was to revise decellularization protocols in combination with enzymatic deglycosylation, in order to reduce the immunogenicity of porcine pulmonary heart valves, in means of cells, carbohydrates, and, primarily, Galα1-3Gal (α-Gal) epitope removal. In particular, the valves were decellularized with sodium dodecylsulfate/sodium deoxycholate (SDS/SD), Triton X-100 + SDS (Tx + SDS), or Trypsin + Triton X-100 (Tryp + Tx) followed by enzymatic digestion with PNGaseF, Endoglycosidase H, or O-glycosidase combined with Neuraminidase. Results showed that decellularization alone reduced carbohydrate structures only to a limited extent, and it did not result in an α-Gal free scaffold. Nevertheless, decellularization with Tryp + Tx represented the most effective decellularization protocol in means of carbohydrates reduction. Overall, carbohydrates and α-Gal removal could strongly be improved by applying PNGaseF, in particular in combination with Tryp + Tx treatment, contrary to Endoglycosidase H and O-glycosidase treatments. Furthermore, decellularization with PNGaseF did not affect biomechanical stability, in comparison with decellularization alone, as shown by burst pressure and uniaxial tensile tests. In conclusion, valves decellularized with Tryp + Tx and PNGaseF resulted in prostheses with potentially reduced immunogenicity and maintained mechanical stability