Protein adsorption in glutaraldehyde-preserved bovine pericardium and porcine valve tissues

Background. Proteins adsorbed by bioprosthetic tissues after implantation play a major role in the process of calcification. We investigated whether there are differences in protein adsorption between bovine pericardial and porcine valvular tissues that could correlate with the differences observed clinically. Methods. Glutaraldehyde-treated bovine pericardial and porcine valve samples were implanted subcutaneously in rats and retrieved 1 month after implantation. Total protein content was assessed by Lowry's method. Qualitative analysis was performed by polyacrylamide gel electrophoresis. Quantitative analysis was performed by densitometry. Results. Total protein content showed a higher protein concentration in porcine valve tissue than in pericardial tissue: 149 +/- 22.6 mug/mg dry tissue versus 108 +/- 12.7 mug/mg dry tissue (38% increase). In pericardial tissue, four protein bands (17, 16, 15.5, and 13.5 kd) showed decreased concentration when compared with porcine valve tissue, whereas one band (11 kd) showed increased concentration. Conclusions. Significant differences were found in protein content between bovine pericardial and porcine valve tissues. Correlations with clinical findings may lead to a better understanding of the mechanism involved in the process of calcification, particularly the role played by the structure of the tissues. (C) 2001 by The Society of Thoracic Surgeons.