AN IN-VITRO DIFFUSION-MODEL FOR THE STUDY OF CALCIFICATION OF BOVINE PERICARDIUM TISSUE

Bovine pericardium (BP) is extensively used for the production of hear t valve bioprostheses, BP has excellent mechanical properties but a li mited lifespan because of intrinsic subsurface calcification in vivo. in this study, the in vitro mineralization of BP was investigated by a novel diffusion cell model. In two sets of experiments, glutaraldehyd e-treated BP membranes were placed between two compartments, both of w hich contained calcium phosphate solutions made by equilibration of oc tacalcium phosphate (Exp I) or dicalcium phosphate dihydrate (Exp II) in phosphoric acid. The movement of calcium (Ca), phosphate (P), and p rotons through the BP membrane was followed throughout the diffusion p rocess. Histology, scanning electron microscopy, wet chemical analysis , and energy dispersive X-ray analyses provided good evidence of subsu rface mineralization of BP that resembled in vivo mineral deposition. Energy dispersive x-ray microanalyses found a Ca/P heterogeneity of th e early subsurface mineral that formed in the membrane. The use of a d iffusion cell to model BP calcification under well-characterized condi tions has led to in vitro mineralization that more closely matches tha t observed in vive. The results suggest that this in vitro difiusion m odel can be used to study the mechanism of pathological mineralization . This model has the potential to provide rapid, inexpensive, basic in formation about the mineralization process.