Copper-related blood indexes in kidney dialysis patients

Abstract

Previous work has suggested that kidney hemodialysis patients could be at risk for either moderate copper deficiency or copper toxicity. The present study examined copper-related blood indexes in subjects undergoing hemodialysis treatments with membranes that are not copper-based, in subjects undergoing chronic ambulatory peritoneal dialysis (CAPD), and in control subjects. Both dialysis groups had low plasma copper and ceruloplasmin activities. This occurred despite high plasma interleukin 6 concentrations, a situation that usually elevates plasma ceruloplasmin and copper values. CAPD and hemodialysis subjects had low ratios of ceruloplasmin activity to immunoreactive protein, and low ratios of plasma copper to ceruloplasmin protein. Both are signs of copper deficiency. In contrast, copper-containing erythrocyte superoxide dismutase (SOD) activities were high in hemodialysis subjects and showed a nonsignificant trend toward high values in CAPD subjects. Blood mononuclear cell copper contents were highly variable within each group, and there were no significant differences between groups. In conclusion, ceruloplasmin-related indexes in kidney dialysis patients not dialyzed with copper-based membranes suggested a tendency toward moderate copper deficiency. However, this contention could not be confirmed by erythrocyte SOD activity or mononuclear cell copper measurements.