Biocompatibility Assessment of a Hybrid Material Based on Epoxy-Treated Pericardium and Polyvinyl Alcohol Cryogel in...

The aim of the study was to evaluate the biocompatibility of a hybrid material based on epoxy-treated bovine pericardium and cryostructured polyvinyl alcohol (PVA) after implantation into the rat aortic wall and subcutaneous tissue.

The study evaluated hybrid material patches based on epoxy-treated bovine pericardium and cryostructured PVA; unmodified "KemPeriplasNeo" pericardial patches served as controls. The samples were implanted into the abdominal aortic wall and subcutaneously in male Wistar rats. The vascular implantation periods were 5 and 20 days, and the subcutaneous implantation periods were 60 and 120 days. The specimens were excised from the aorta and studied histologically using Russell-Movat staining and immunostaining for neutrophil myeloperoxidase (MPO) and the macrophage marker CD68. The calcium content in subcutaneously implanted samples was assessed by spectrophotometry and alizarin red S staining. The quantitative data were presented as the median, percentiles, minimal and maximal values (Me [25%-75%; min-max]).

After implantation into the abdominal aortic wall, the hybrid material samples showed a lower tendency toward thrombotic deposit formation on the surface compared to the pericardium. On day 5 of implantation, the thrombus thickness was 49.1 [34.7-64.6; 27.4-71.6] μm in the experimental group vs 170.3 [158.1-210.3; 124.4-217.0] μm in the controls (p<0.001). By day 20 of implantation, the macrophage density was lower in the peri-implant area of the modified samples compared to the controls: 219 [187-275; 112-362] vs 301 [244-338; 194-433] CD68⁺ cells per field of view (p<0.001), respectively. The neutrophil density at all experimental time points, as well as the macrophage density on day 5 of implantation did not differ significantly between the tested materials (p>0.17). No signs of calcification were detected in either group following the subcutaneous implantation over a period of 60 or 120 days. The control pericardium in the subcutaneous model showed the signs of cell-mediated degradation, whereas the hybrid samples were resistant to immune-cell infiltration and preserved their internal architecture.

The modification of epoxy-treated bovine pericardium with cryostructured PVA cryogel improved its biocompatibility and enhanced resistance to biodegradation in a rat model after aortic-wall and subcutaneous implantation. The developed material may be used to create next-generation heart valve bioprostheses with potentially improved resistance to structural valve degeneration.