Inhibition of the calcification of porcine valve tissue by selective lipid removal

Abstract Since the development of cardiac prostheses, numerous chemical treatments have been assayed to prevent the process of their mineralization, causing 60% of the failures. The effect of the extraction of lipids from the tissue employed in porcine valves is assessed in a model of subcutaneous implantation in rats. Tissue from aortic and pulmonary porcine valves was treated with chloroform-methanol and 0.625% glutaraldehyde and was implanted into young rats for periods of 21 and 60 d. The calcium accumulated was then quantified by atomic absorption. The effectiveness of this treatment is demonstrated by the detection of much lower calcium values than in the control group. For aortic valve tissue, the values obtained were 40.5 and 188.1 μgCa 2+ /mg dry weight of tissue for implantation times of 21 and 60 d, respectively, versus 5.48 and 1.4μgCa 2+ /mg dry weight of tissue for the same tissue treated with chloroform-methanol. The values obtained with pulmonary valve tissue were very similar: 72.46 and 108.06 μgCa 2+ /mg dry weight tissue versus 0.67 and 0.80 μgCa 2 /mg dry weight tissue for implantation periods of 21 and 60d, respectively. Thus, phospholipids may be totally or partially responsible for the calcification of the porcine valve tissue employed in the construction of cardiac bioprostheses. Biomaterials (1994) 15 , (10) 815–820