Enhanced biostability and biocompatibility of decellularized bovine pericardium, crosslinked with an ultra-low concentration monomeric aldehyde and treated with ADAPT.

Matrix preparation remains controversial due to incomplete cell removal, inflammatory responses, reabsorption and thrombocyte activation. Previously, crosslinked matrices have been considered unsatisfactory due to cytotoxicity. In the present study, the biostability, biocompatibility and calcification potential of a decellularized matrix crosslinked with a low concentration of monomeric glutaraldehyde (GA) and treated with the ADAPT anti-calcification process were examined.Bovine pericardium was decellularized with Triton X-100, deoxycholate, IgePal CA-630 and ribonuclease. The resulting matrices were allocated to either group I (control, n = 5), crosslinked in 0.2% polymeric GA + ADAPT, or to group II (treatment, n = 5), crosslinked in 0.05% monomeric GA + ADAPT. The physical properties, enzymatic degradation, histology and immunohistochemical staining of the tissues were monitored. The matrices were also implanted in the jugular vein of juvenile sheep for 200 days.Complete acellularity was achieved. Biostability was significantly (p <0.01) enhanced in group II, but inflammatory responses were limited in both groups. Host fibroblasts infiltrated the periphery in group I and the entire matrix in group II. The luminal surfaces were free from thrombotic depositions and covered with endothelial cells. Both groups tested positive for Factor VIII, smooth muscle alpha-actin and vimentin. Tissue extractable calcium levels were low (group I = 1.02 +/- 0.39, group II = 0.86 +/- 0.22 microg Ca/mg tissue).Low-concentration GA-crosslinked matrices proved to be stable. The immunoreactivity of both groups was low, with host cell infiltration, migration and trans-differentiation being optimized in those grafts crosslinked with an ultra-low monomeric GA concentration. Calcification levels were close to zero in both groups. Enhanced crosslinking and effective anti-calcification produce a biomaterial with advanced in-vivo tissue-engineering properties.