Preventing extrinsic mechanisms of bioprosthetic degeneration using polyphenols.

OBJECTIVES: The purpose of this study was to evaluate the impact of a polyphenols-based treatment on the extrinsic mechanisms responsible for early bioprosthetic heart valve (BHV) degeneration. Structural degeneration can be driven by both extrinsic and intrinsic mechanisms. While intrinsic mechanisms have been associated with inherent biocompatibility characteristics of the BHV, the extrinsic ones have been reported to involve external causes, such as chemical, mechanical and hydrodynamic, responsible to facilitate graft damage. METHODS: The chemical interaction and the stability degree between polyphenols and pericardial tissue were carefully evaluated. The detoxification of glutaraldehyde in commercial BHVs models and the protective effect from in vivo calcification were taken into relevant consideration. Finally, the hydrodynamic and biomechanical features of the polyphenols-treated pericardial tissue were deeply investigated by pulse duplicator and stress-strain analysis. RESULTS: The study demonstrated the durability of the polyphenols-based treatment on pericardial tissue and the stability of the bound polyphenols. The treatment improves glutaraldehyde stabilization's current degree, demonstrating a surprising in vivo anti-calcific effect. It is able to make the pericardial tissue more pliable while maintaining the correct hydrodynamic characteristics. CONCLUSIONS: The polyphenols treatment has proved to be a promising approach capable of acting simultaneously on several factors related to the premature degeneration of cardiac valve substitutes by extrinsic mechanisms.

A Comprehensive Comparison of Bovine and Porcine Decellularized Pericardia: New Insights for Surgical Applications.

Xenogeneic pericardium-based substitutes are employed for several surgical indications after chemical shielding, limiting their biocompatibility and therapeutic durability. Adverse responses to these replacements might be prevented by tissue decellularization, ideally removing cells and preserving the original extracellular matrix (ECM). The aim of this study was to compare the mostly applied pericardia in clinics, i.e. bovine and porcine tissues, after their decellularization, and obtain new insights for their possible surgical use. Bovine and porcine pericardia were submitted to TRICOL decellularization, based on osmotic shock, detergents and nuclease treatment. TRICOL procedure resulted in being effective in cell removal and preservation of ECM architecture of both species' scaffolds. Collagen and elastin were retained but glycosaminoglycans were reduced, significantly for bovine scaffolds. Tissue hydration was varied by decellularization, with a rise for bovine pericardia and a decrease for porcine ones. TRICOL significantly increased porcine pericardial thickness, while a non-significant reduction was observed for the bovine counterpart. The protein secondary structure and thermal denaturation profile of both species' scaffolds were unaltered. Both pericardial tissues showed augmented biomechanical compliance after decellularization. The ECM bioactivity of bovine and porcine pericardia was unaffected by decellularization, sustaining viability and proliferation of human mesenchymal stem cells and endothelial cells. In conclusion, decellularized bovine and porcine pericardia demonstrate possessing the characteristics that are suitable for the creation of novel scaffolds for reconstruction or replacement: differences in water content, thickness and glycosaminoglycans might influence some of their biomechanical properties and, hence, their indication for surgical use.