Aldehyde reduction in a novel pericardial tissue reduces calcification using rabbit intramuscular model

Abstract

Calcification is a major factor that limits the durability of bioprosthetic valve. A novel bovine pericardial tissue treated with aldehyde capping chemistry and glycerolization was evaluated for its resistance to calcification in comparison with porcine tissues treated with amino oleic acid and bovine pericardial tissue with ethanol rinsing in a rabbit intramuscular model. Tissue discs from the test and control tissues were implanted in rabbits for 60 days. The explanted discs were subject to X-ray imaging, calcium quantification and histology analysis. The test tissue showed 95 and 96 % reduction in calcification in comparison with amino oleic acid treatment and ethanol rinsing treatment, respectively. In addition, the test tissue showed the least inflammatory response as evidenced by a reduced amount of macrophages and giant cells in histology analysis. Furthermore, the aldehyde analysis of the pre-implanted samples showed associated reduction in free aldehyde levels with the test tissue. The reduction in calcification is consistent with previously reported results and is hypothesized to be attributed to the capping of free aldehydes in the test tissue.

Fig. 1

Box and Whisker plot of calcium contents of explanted tissue discs

Fig. 2

Representative X-ray images of tissue discs after explant of test group (a), porcine tissue treated with AOA (b), bovine pericardial tissue treated with Linx (c) and bovine pericardial tissue treated with glutaraldehyde only (d). The white area represents the calcified nodule. The X-ray images were sorted based on the calcium content and the median calcium images were selected as representative

Fig. 3

Free aldehyde content of pre-implanted tissue. Ten samples were measured for each group

Fig. 4

Representative H&E images of test (a), porcine tissue with AOA (b), bovine pericardium with Linx (c) and glutaraldehyde only tissue (d) tissue after 60 day implant. The left images are 25× and the right images are 400×. The blue dots are the giant cells and macrophages

Fig. 5

Representative von Kossa images of test (a), porcine tissue with AOA (b), bovine pericardium with Linx (c) and glutaraldehyde only tissue (d) tissue after 60 day implant. The left images are 25× and the right images are 400×. The brown color is the calcified sites