Bioprosthetic heart valves with reduced immunogenic residuals using vacuum-assisted decellularization treatment

Despite the good hemodynamic characteristics of bioprosthetic heart valves, it is inevitable that they will suffer from calcification and tissue deterioration. Decellularization has been utilized to reduce the immunogenicity and calcification of bioprosthetic heart valves. However, it can take several days or even weeks to obtain the decellularized tissues or organs. Therefore, time-frame should be taken into consideration during the decellularization process. A detergent-enzymatic-method, combined with vacuum, has been proposed as a method of obtaining desirable decellularized heart valves. In this study, heart valves treated under vacuum and normal atmosphere are investigated via histological, biochemical and mechanical analysis. The results show that the decellularization efficiency of heart valves treated under vacuum is enhanced, based on histological staining, DNA contents and α-Gal quantification. The decellularization procedures decrease the contents of the extracellular matrix. However, the mechanical properties, including elastic modulus, fracture tensile strength and fracture strain, show no significant difference between the samples. In vitro cell cytotoxicity experiments indicate the feasibility of further in vivo experiments. Therefore, we conclude that vacuum-assisted decellularization procedures can significantly enhance decellularization efficiency by reducing the decellularization time, without compromising the properties of the heart valves, which is also beneficial in terms of reducing clinical costs. To the best of our knowledge, vacuum is a novel parameter which can be designed into decellularization procedures for heart valves.