Trace elements in hemodialysis and continuous ambulatory peritoneal dialysis patients

Alterations in blood and tissue concentrations of trace elements in patient s with chronic renal failure have been extensively investigated. Selenium, zinc and copper are elements which play an important role in biological sys tems as components of proteins, enzymes and antioxidants. The concentration s of selenium, zinc and copper were determined in the plasma, erythrocytes and whole blood of patients on regular hemodialysis (HD) and continuous amb ulatory peritoneal dialysis (CAPD) treatment using the method of inductivel y coupled plasma mass spectrometry (ICP-MS). Analysis of isotopes Se-77, Zn -66 and Cu-65 was performed. Methodology presents the major limitation to v alid studies on trace element levels in biological materials. One of the wi dely used contemporary techniques is ICP-MS. It is the most sensitive one a nd has a high dynamic range. The selenium concentration in the studied comp artments (plasma 46.1 +/- 3.0 vs. 78.0 +/- 3.4 mu g/l, p < 0.001; erythrocy tes 90.4 +/- 6.5 vs. 134.2 +/- 7.6 mu g/l, p < 0.01; whole blood 67.3 +/- 3 .1 vs. 106.4 +/- 3.4 mu g/l, p < 0.001) was significantly lower in HD patie nts compared to healthy controls. The same result was Observed in plasma (6 3.2 +/- 5.8 vs. 78.0 +/- 3.4 mu g/l, p < 0.05) and whole blood (82.7 +/- 7. 4 vs. 106.4 +/- 3.4 mu g/l, p < 0.01) from CAPD patients, but the selenium level of erythrocytes in CAPD patients was the same as in the control group (126.0 +/- 8.8 vs. 134.2 +/- 7.6 mu g/1). The cooper content of erythrocyt es was lower in HD patients than in controls (0.55 +/- 0.02 vs. 0.66 +/- 0. 01 mg/l, p < 0.01) and CAPD groups (0.55 +/- 0.02 vs. 0.68 +/- 0.02 mg/l, p < 0.001). There were no differences in copper content in plasma (HD 1.02 /- 0.06; CAPD 1.11 +/- 0.09; controls 1.02 +/- 0.05 mg/l) and whole blood ( HD 0.87 +/- 0.04; CAPD 0.90 +/- 0.05; controls 0.85 +/- 0.02 mg/l) in HD an d CAPD patients and healthy controls. The zinc concentration was increased in the whole blood of CAPD patients (6.68 +/- 0.36 vs. 5.52 +/- 0.11 mg/l, p < 0.001) and erythrocytes of HD (12.30 +/- 0.23 vs. 10.11 +/- 0.42 mg/I, p < 0.001). and CAPD groups (13.71 +/- 0.56 vs. 10.11 +/- 0.42 mg/l, p < 0. 001) compared to controls. However, the plasma zinc concentration was lower in HD patients compared to blood donors (0.69 +/- 0.03 vs. 0.92 +/- 0.03 m g/l, p < 0.001) and CAPD patients (0.69 +/- 0.03 vs. 0.95 +/- 0.04 mg/I, p < 0.001). We did not find a significant increase in trace elements in whole blood after HD. These results suggest differences between plasma, erythroc ytes and whole blood concentrations of the studied trace elements. The leve ls of trace elements are altered by HD and CAPD. A modern precise method wi th high accuracy, ICP-MS, which was used in our study, eliminated analytica l errors and possible interferences.