Copper accumulation in primary biliary cirrhosis. An electron and X-ray microanalytical study.

Ultrastructural and X-Ray microanalytical aspects of primary biliary cirrhosis were analysed and compared to those of normal liver. Electron microscopic studies showed a significant increase of dense lipofuscin-like granules in PBC compared to the hepatocytes of normal liver (665%). These granules (0.3-2.7 micrometers in diameter) were formed by the association of primary lysosomes and lipid droplets. X-Ray microanalysis of these structures showed the presence of Calcium, Phosphorus, Potassium, Chlorine, Sulphur, Aluminium and Copper. The coexistence of Sulphur with other mineral elements suggests the occurrence of metalloproteins binding these elements. These findings provide evidence that intralysosomal sequestration of mineral elements, especially copper protects the hepatocytes from cytotoxic effects.