Differential distribution of structural components and hydration in aortic and pulmonary heart valve conduits: Impact of detergent-based cell removal

Evaluation of the physiological performance of biological scaffolds for tissue engineering applications has been mostly based on biophysical and morphological methods, with limited attention paid to the quantitative contribution of the main structural components to native and/or treated valve assemblies. In the present study quantitation addressed the porcine leaflet, sinus and adjacent wall of aortic and pulmonary valved conduits before and after detergent-based cell removal. Collagen, elastin, glycosaminoglycan, lipid and water contents were expressed in terms of relative concentration and volume fraction in order to assess their effective contribution to the native tissue and to changes following decellularization procedures. The main findings were recognition of unexpectedly large water and underestimated collagen contents, differential distribution of elastin between the sectors and of glycosaminoglycan along the conduits and pulmonary scaffold destabilization upon cell removal, not found in the aortic case. Simultaneous investigations allowed consistent comparisons between native and decellularized tissues and added analytical knowledge crucial for designing realistic constitutive models. We have provided a quantitative structural foundation for earlier biomechanical findings in pulmonary leaflets and the basis for validation of theoretical assumptions still lacking the support of experimental evidence in both conduits. Future insights into the distribution of load-bearing components in human conduits are likely to provide indications important to optimize the surgical positioning of valvular grafts.