Evaluation of distribution patterns for copper and zinc in metallothionein and superoxide dismutase in chronic liver diseases and hepatocellular carcinoma using high-performance liquid chromatography (HPLC)

Abstract

It has been reported that the copper (Cu) content of hepatocytes increases in chronic liver diseases and small hepatocellular carcinoma (HCC). In cells, Cu exists mainly as Cu-metallothionein (MT) or Cu, zinc (Zn)-superoxide dismutase (SOD). In this study, we investigated the biochemical state of Cu in the hepatocytes of patients with HCC using high-performance liquid chromatography (HPLC). The subjects of present study were 23 patients with HCC who underwent liver resection. The cancerous tissue and non-cancerous hepatic parenchyma with chronic disease were analyzed. In addition, as a normal control, hepatic tissue was collected at autopsy from 13 patients with no liver disease. Each sample was diluted with buffer, chilled, homogenized, and centrifuged. The supernatant was fractionated using HPLC. The metal contents of each fraction were measured using a desktop-type inductively coupled plasma (ICP) emission spectrochemical analyzer. HPLC analysis showed that MT existed mainly as Zn-MT in the normal hepatic tissue. The case of Cu,Zn-MT was significantly greater than Zn-MT in the non-cancerous, but diseased hepatic parenchyma than in the normal hepatic tissue (p<0.01). In comparison with non-cancerous hepatic parenchyma, the Cu-MT in the cancerous section was significantly greater than the Cu,Zn-MT (p<0.01). The Cu content for MT was significantly higher in small HCC (<40mm) (p<0.01), and the absence of Cu or Zn in the MT fraction was significantly more frequent in the large HCC (≧40 mm) (p<0.01). The Cu and Zn content for SOD in the samples showed no significant difference. Increase in the Cu content in the cancerous hepatic tissue were, thought to be reflecting changes in the distribution of Cu in the MT fraction of hepatic tissues. © 2005 Pharmaceutical Society of Japan.