Conclusion
The suggested modification of epoxy-treated bovine pericardium with polyvinyl alcohol prevents the adhesion of immune cells to the implant surface and can potentially protect bioprosthetic heart valves from immune rejection.
Methods
Fragments of unmodified (control) and modified with polyvinyl alcohol epoxy-treated bovine pericardium were incubated in the dedicated chambers connected to a pulsatile flow system (Ibidi GmbH, Germany). During 48 h incubation was conducted in whole donor plasma containing 3·106 of mononuclear fraction cells. To simulate plasma flow, the shear stress on the inflow and outflow sides of of bioprosthetic heart valve in the aortic position was set to 50 and 20 dynes/cm2, respectively. After the experiment was completed, the surface of the studied samples was subjected to scanning electron microscopy and immunofluorescence using antibodies to the pan-leukocyte marker CD45.
Results
Adhesion of leukocytes (CD45+) was seen for both the serous (outflow side) and fibrous (inflow side) surfaces of the control epoxy-treated bovine pericardium, whereas both surfaces of the material modified with polyvinyl alcohol were clear of immune cells. Scanning electron microscopy confirmed the adhesion of leukocytes to intact biological tissue: the cells on the surface of the control xenopericardium were of an irregular shape and formed numerous pseudopodia.