Erythrocyte copper chaperone for superoxide dismutase is increased following marginal copper deficiency in adult and postweanling mice.

A sensitive and reliable biomarker has yet to be identified for marginal copper deficiency in humans. The need for such a biomarker is critical, because increased cases of human copper deficiency evolve following bariatric surgery and other secondary factors besides diet. Four experiments were devised to induce marginal copper deficiency through copper-deficient (CuD) diets (5 wk for mice and 4 wk for rats). In Expt. 1 and 2, male postweanling mice were raised in either solid-bottom plastic cages (Expt. 1) or stainless steel hanging cages (Expt. 2) and compared. Postweanling rats (Expt. 3) and adult mice (Expt. 4) were also studied using stainless steel cages. Copper-adequate controls were fed a semipurified diet containing 9 mg Cu/kg. CuD rats exhibited the most severe changes in biomarkers due to copper limitation, including major reductions in plasma ceruloplasmin (Cp) and erythrocyte superoxide dismutase (Sod1) and augmentation in copper chaperone for Sod1 (CCS). The CuD mice in Expt. 2 were more deficient than the CuD mice in Expt. 1, likely due to coprophagia differences. In fact, the CuD mice in Expt. 1 had unaltered Sod1 or Cp levels. Importantly though, these marginally deficient mice and CuD adult mice that had no changes in Cp activity or liver copper level had robust augmentation of CCS. Erythrocyte CCS was the only consistent biomarker to change in copper deficiency for all dietary groups, suggesting that CCS may be an excellent biomarker for human confirmation of marginal copper deficiency.

Rapid alteration in rat red blood cell copper chaperone for superoxide dismutase after marginal copper deficiency and repletion.

There is increased incidence of human copper deficiency (CuD). A sensitive and reliable blood biomarker may reveal additional cases of marginal deficiency. Two experiments were designed to test the hypothesis that the copper chaperone for superoxide dismutase (CCS) would be a robust marker after marginal CuD. Experiment 1 used weanling male Sprague-Dawley rats that were offered a CuD diet for 4 weeks, and samples were evaluated after 1, 2, and 4 weeks and compared with copper-adequate (CuA) controls. Furthermore, iron-deficient rats were included for comparison after 2 weeks of depletion. Red blood cell and plasma cuproenzymes were evaluated through Western blot analysis. Superoxide dismutase (Sod1) and ceruloplasmin protein were found to be altered by both iron and CuD, whereas CCS and CCS/Sod1 ratio were found to only be altered only in CuD rats and, importantly, after only 1 week of treatment. Two weeks on CuA diet restored cuproenzyme levels to control values after 4 weeks of CuD depletion. In experiment 2, marginal CuD (CuM) rats were compared with CuA and CuD rats after 2 weeks of treatment. Superoxide dismutase, ceruloplasmin, and CCS/Sod1 abundances were lower in CuM and CuD groups compared with CuA rats, but there was no statistical difference between CuM and CuD rats. However, CCS was statistically different between all groups, and abundance highly correlated with liver copper concentration. Results suggest that red blood cell CCS may be an excellent biomarker for diagnosis of rapid and marginal CuD.

Maternal iron supplementation attenuates the impact of perinatal copper deficiency but does not eliminate hypotriiodothyroninemia nor impaired sensorimotor development.

Copper, iron and iodine/thyroid hormone (TH) deficiencies disrupt brain development. Neonatal Cu deficiency causes Fe deficiency and may impact thyroidal status. One purpose of these studies was to determine the impact of improved iron status following Cu deficiency by supplementing the diet with iron. Cu deficiency was produced in pregnant Holtzman [Experiment 1 (Exp. 1)] or Sprague-Dawley [Experiment 2 (Exp. 2)] rats using two different diets. In Exp. 2, dietary Fe content was increased from 35 to 75 mg/kg according to NRC guidelines for reproduction. Cu-deficient (CuD) Postnatal Day 24 (P24) rats from both experiments demonstrated lower hemoglobin, serum Fe and serum triiodothyronine (T3) concentrations. However, brain Fe was lower only in CuD P24 rats in Exp. 1. Hemoglobin and serum Fe were higher in Cu adequate (CuA) P24 rats from Exp. 2 compared to Exp. 1. Cu- and TH-deficient rats from Exp. 2 exhibited a similar sensorimotor functional deficit following 3 months of repletion. Results suggest that Cu deficiency may impact TH status independent of its impact on iron biology. Further research is needed to clarify the individual roles for Cu, Fe and TH in brain development.