Impact of Three Different Processing Techniques on the Strength and Structure of Juvenile Ovine Pulmonary Homografts

Abstract

Homografts are routinely stored by cryopreservation; however, donor cells and remnants contribute to immunogenicity. Although decellularization strategies can address immunogenicity, additional fixation might be required to maintain strength. This study investigated the effect of cryopreservation, decellularization, and decellularization with additional glutaraldhyde fixation on the strength and structure of ovine pulmonary homografts harvested 48 h post-mortem. Cells and cellular remnants were present for the cryopreserved group, while the decellularized groups were acellular. The decellularized group had large interfibrillar spaces in the extracellular matrix with uniform collagen distribution, while the additional fixation led to the collagen network becoming dense and compacted. The collagen of the cryopreserved group was collapsed and appeared disrupted and fractured. There were no significant differences in strength and elasticity between the groups. Compared to cryopreservation, decellularization without fixation can be considered an alternative processing technique to maintain a well-organized collagen matrix and tissue strength of homografts.

Monomeric glutaraldehyde fixation and amino acid detoxification of decellularized bovine pericardium for production of biocompatible tissue with tissue-guided regenerative potential

“…GA and monomeric GA fixation was done in phosphate buffer (KH 2 PO 4 , pH 7.4) for 72 h at 4 °C, followed by the addition of hydrogen peroxide (H 2 O 2 ) in phosphate buffer for 4 h at 4 °C. Following fixation, tissue was detoxified using 100% propylene glycol [ 28 ] or an amino acid solution containing 0.1 M glycine [ 29 ].…”

“…The degree of cross-linking was calculated using equation (1) . where; Mo is the number of free amine groups in the non-cross-linked tissue, and Mt is the number of amine groups remaining in the cross-linked tissue, both normalized to tissue weight [ 28 ]. Decellularized tissue fixed with decreasing concentrations (0.625%, 0.1%, and 0.05%) of monomeric GA without the addition of H 2 O 2 was included for comparison.…”