Donkey pericardium as a select sourcing to manufacture percutaneous heart valves: Decellularization has not yet demonstrated any clear cut advantage to glutaraldehyde treatment

The donkey pericardium is considered a good candidate to manufacture percutaneous heart valves based upon its thinness, low cellularity and undulating collagen bundles and laminates. Decellularization represents an avenue worth exploring, should its superiority to glutaraldehyde-treated pericardium be demonstrated. Donkey pericardium was divided into two groups: regular glutaraldehyde fixation and mild decellularization. The treated pericardia were observed using scanning electron microscopy, histology and transmission electron microscopy. Tensile tests were performed along the axial and perpendicular directions, with the data fitted into both the Gasser–Ogden–Holzapfel (GOH) material model and the Fung’s anisotropic one. The microstructures of the pericardia processed by the two protocols were similar, showing collagen bundles and laminates free of flaws. The decellularization eliminated most of the cells, however leaving the structure somehow compressed. The collagen filaments in bundles were slightly blurry. The anisotropy rates of the non-decellularized specimens were almost identical to the decellularized ones. The decellularized pericardium appeared stiffer. The decellularization proved to be effective. However, it makes the tissue stiffer, which may lead to higher shear concentration during cardiac cycles and reduce its wavy microstructure. Therefore, it appears premature to select decellularized donkey pericardium to manufacture heart valves.