Histological demonstration of copper and copper-associated protein in chronic liver diseases

Value of copper-associated protein in diagnostic assessment of liver biopsy

Of 1361 consecutive liver biopsy specimens, 24% contained orcein-positive granules. The highest incidence of positivity was found in biliary disease (90.9%), long before cirrhosis had developed, whereas in chronic non-primarily biliary disease, positive results were almost exclusively in patients with well established cirrhosis. Orcein-positive granules were never found in acute liver disease. These granules were also demonstrated in tumour cells of primary hepatocellular tumours (benign 4 of 4 cases; malignant 9 of 37 cases), while all the secondary tumour deposits were negative. In our view the additional information obtained by this technique warrants its adoption as a routine procedure.

Hepatic copper in Indian childhood cirrhosis

Forty-three liver biopsies histologically diagnosed as Indian childhood cirrhosis were studied with the object of investigating accumulation of copper and copper-associated protein in the hepatocytes as demonstrated by the rhodanine and orcein stains respectively. The findings reveal that, in almost all cases, there was an increased accumulation of copper and copper-associated protein, accompanied by the presence of numerous Mallory bodies. It is postulated that the accumulation of copper in the hepatocytes might be the result of a metabolic defect and might be aetiologically related to the liver cell injury and the subsequent development of Indian childhood cirrhosis.

Is copper hepatotoxic in primary biliary cirrhosis?

In primary biliary cirrhosis (PBC) liver copper retention occurs as a complication of cholestasis. By analogy with Wilson's disease, it has been suggested that copper retention is hepatotoxic in PBC, and this has been the rationale for the use of D-penicillamine in this disease. The hypothesis that copper is hepatotoxic in PBC has not been tested and in this study we have evaluated the role of liver copper retention in the pathogenesis of PBC. Sixty-four patients with PBC have been studied. Fifty-four had increased liver copper concentrations. Liver cell synthetic function was well preserved. All the patients had normal prothrombin times, and only two had subnormal serum albumin concentrations. There was no correlation between liver copper concentrations and the degree of liver cell damage assessed biochemically (aspartate transaminase), and histologically. Electron microscopy was performed on liver biopsies from five patients with markedly increased liver copper concentrations. The liver cell ultrastructure was compatible with cholestasis. Liver cells contained electron dense lysosomes, which were shown to contain copper and sulphur by x-ray probe microanalysis. The characteristic organelle changes associated with copper toxicity in Wilson's disease were not observed. The biochemical, histological, and histochemical differences between PBC complicated by liver copper retention, and Wilson's disease, indicates that there are differences in the handling of copper in these disease. In this study we could find no evidence to suggest that copper plays an important role in the pathogenesis of liver dysfunction in PBC.

Orcein as a mucin stain for gastrointestinal tissue sections

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Alpha-I-antitrypsin and copper in the liver

The incidental finding of orcein positive granules, indicating copper associated protein, in alpha-1-antitrypsin (AAT) positive liver biopsies stimulated a histochemical search for evidence of copper and copper-binding protein in a series of 46 liver biopsies with histological evidence of AAT accumulation. Hepatic accumulation copper and copper-binding protein occurred in all 19 cirrhotics (100%) and in 14 out of 27 non-cirrhotic livers (51.85%). The overall percentage was 71.73%. AAT and copper deposits coexisted in the same periportal hepatocytes. AAT globules showed positive reactivity both to rhodanine and orcein stains. The severity of chronic liver damage correlated with increasing amounts of copper deposition. It is suggested that in AAT storage, not only is the metabolism of this substance disturbed, but also that of proteins involved in copper metabolism and excretion, resulting in copper accumulation within hepatocytes.

Is mitochondrial antibody diagnostic of primary biliary cirrhosis?

In a series of 218 patients diagnosed as having primary biliary cirrhosis only nine exhibited a negative serum mitochondrial antibody. On examining additional specimens from these patients, seven were found to be positive, giving a final incidence of greater than 99%. The two patients whose sera remained negative for the mitochondrial antibody had liver histology compatible with the diagnosis of primary biliary cirrhosis, but a firm diagnosis could not be reached. Three additional mitochondrial antibody positive subjects who were asymptomatic and exhibited normal serum alkaline phosphatase were shown on liver biopsy to have stage I primary biliary cirrhosis. The presence of a positive serum mitochondrial antibody in a patient with or without abnormalities in liver function tests strongly suggests the diagnosis of primary biliary cirrhosis.

Observations on copper associated protein in childhood liver disease

Hepatic copper concentrations were compared with staining grades of copper associated protein (CAP) and histochemical copper in liver sections from 44 patients (one fetus, one pre-term infant, four term infants, eight normal children, 16 children with various liver diseases, and 14 patients with intrahepatic cholestasis of childhood (IHCC)). A similar comparative study of hepatic copper concentration with CAP and histochemical copper was performed in 21 patients with Wilson's disease. CAP occurred in the fetus, pre-term infant, and term infants without liver disease. This suggests that CAP is a normal constituent of the hepatocyte and is not a consequence of liver disease or biliary obstruction. CAP was not seen when hepatic copper concentration was normal; it was absent in eight children with no evidence of liver disease, eight children with non-cirrhotic liver disease, and seven of eight children with cirrhosis. When hepatic copper concentration exceeded 4.0 mumol/g dry liver weight grade 2 or grade 3 staining for CAP and histochemical copper was found in the fetus, pre-term infant, infants, and IHCC. CAP was found in IHCC only in the presence of raised hepatic copper levels, supporting evidence of a relationship between copper and CAP. In 17 of 21 patients with Wilson's disease hepatic copper concentrations exceeded 4 mumol/g. Positive staining for CAP was seen in seven of these patients being usually grade 1. CAP is a normal associated protein, present when hepatic copper concentrations are increased in normal liver cells. It is usually absent in hepatocytes from Wilson's disease despite similar hepatic copper levels. CAP may represent material which protects the hepatocyte from the toxic effects of copper.

Iron, copper, and zinc liver tissue levels in patients with malignant lymphomas

Levels of iron, copper, and zinc in liver tissue and of copper in serum were studied in 53 cases of untreated malignant lymphoma (14 cases of Hodgkin's disease and 17 of lymphocytic and 22 of histiocytic lymphoma). The values were compared with the levels of these metals in the liver tissue of 23 healthy persons. Liver tissue was obtained by means of percutaneous biopsy examination with a Menghini needle. Part of the samples was used for histologic examination, and the remainder for metal level determination. Atomic absorption spectrophotometry was used in determining metal levels in dry liver tissue and in sera. In all malignant lymphoma patients, a significantly higher serum copper level was established (P < 0.05). A lower iron level in liver tissue was only found in those patients with lymphocytic lymphomas without a lymphomatous process in the liver (P < 0.05), while lymphomatous hepatic infiltration was associated with a higher iron level and lower copper level (P < 9.05). Significant changes in liver zinc levels were only proved by higher levels of this metal in patients with histiocytic lymphoma and lymphomatous hepatic infiltration (P < 0.05). The only redistribution of copper between the serum and liver tissue was found in those patients with lymphocytic lymphomas and lymphomatous hepatic infiltration.

The significance of variations in the distribution of copper in liver disease

Biopsy and autopsy specimens of liver from patients with Wilson's disease in various stages, chronic cholestatic conditions (including primary biliary cirrhosis, extrahepatic biliary obstruction, sclerosing cholangitis, and biliary atresia), chronic active hepatitis, and Indian childhood cirrhosis, as well as normal neonates, were examined by means of histochemical techniques for copper and copper-associated protein. The intracellular localization of copper and the lobular distribution of the metal and its associated protein differed in these conditions. Periportal hepatocytes containing granules (lysosomes) that were reactive for copper and for copper-associated protein were characteristic of cholestasis and neonatal liver. However, in cholestasis extralysosomal copper was often present in the hepatocellular cytoplasm. In contrast, in Wilson's disease, despite very high concentrations of copper in the early stages, the metal was diffuse in the cytoplasm, and the histochemical reactions for granular copper and its associated protein were usually negative. Therefore, a failure to stain for copper does not exclude the diagnosis of Wilson's disease. In the late stages of Wilson's disease staining varied in different nodules. In Indian childhood cirrhosis copper was present throughout the parenchyma, with periportal predominance. Differences in the distribution of copper and the cellular changes associated with its deposition suggest that different pathogenetic mechanisms and possibly different intracellular targets are susceptible to the toxic effects of the metal. For diagnosis, staining for copper and for copper-associated protein may assist in the differentiation of primary biliary cirrhosis from chronic active hepatitis.