Relationship between the Trace Element Metabolism and the AntioxidantDefence System in Chronic Nephropathies

Overview

Background.
Trace elements - zinc, copper and selenium are part of antioxidant enzymes, superoxide dismutase(SOD) and glutathione peroxidase (GHPx). In renal diseases changes in the trace element metabolism may influencethe equilibrium in the antioxidant defence system and enhance the toxic effect of reactive oxygen molecules.Methods and Results. The authors examined in 53 children with chronic neprophathies (34 with chronicglomerulonephritis, 11 with chronic renal failure and 8 children included in a chronic dialyzation programme) zincand selenium in blood and urine and antioxidant enzymes SOD and GHPx in red blood cells. The lowest SOD activity(737 ± 219 U/g Hb, p < 0.01) and serum zinc concentration (12.9 ± 3.2, p < 0.05) were found in children in theterminal stage of uraemia, GHPx was as compared with the group of healthy children elevated in all groups of sickchildren. In dialysed children GHPx was highest (p < 0.01) and correlated with urinary selenium concentrations(r = -0.86, p < 0.05). The SOD activity depended on the serum copper concentrations (r = 0.78, p < 0.05). The highestrenal zinc and selenium excretion was recorded in patients with glomerulonephritis (p < 0.05).Conclusions. The results support the hypothesis on a causal relationship between trace elements and antioxidantenzymes.

Key words:
SOD, GHPx, zinc, selenium, kidneys, chronic renal failure.