Exchange of alkali trace elements in hemodialysis Patients: a comparison with Na(+) and K(+)

Serum Trace Elements in Children with End-Stage Renal Disease

OBJECTIVES

Trace elements, which have a crucial role in metabolism and enzymatic pathways, are not routinely monitored in the blood of pediatric patients with chronic kidney disease. The present study was carried out to determine the serum levels of copper (Cu), zinc (Zn), selenium (Se), and lead (Pb) in children with ESRD who were currently receiving conservative management or were on long-term hemodialysis or continuous ambulatory peritoneal dialysis.

METHODS

This study involved 200 children who met the inclusion criteria. The children were divided into 4 groups: a hemodialysis group, a peritoneal dialysis group, a group of children with ESRD treated with conservative management, and a control group. Serum levels of Zn, Cu, Se, and Pb were evaluated using an atomic absorption spectrophotometer and compared between the groups.

RESULTS

There was no significant difference in the serum concentration of Cu among the 4 study groups. There was also no significant difference in the serum concentrations of Zn, Se, and Pb between healthy children and children with CKD treated with conservative management or between the hemodialysis and peritoneal dialysis groups. The levels of Zn and Se were significantly lower in the hemodialysis and peritoneal dialysis groups than in the healthy children or in children with CKD treated with conservative management. The level of Pb in the blood was significantly lower in healthy children and children with CKD treated with conservative management than in the hemodialysis or peritoneal dialysis groups.

CONCLUSIONS

The levels of trace elements were substantially different between the dialysis groups and healthy children and children with CKD treated with conservative management. These results highlighted the role of osmosis during dialysis, as dialysate impurities can cause a disturbance in the levels of trace elements and the role of the kidney, even with minimum residual function, in the homeostasis of trace elements.

Comparative evaluation of essential and toxic elements in the blood of kidney failure patients and healthy referents

The aim of the present study was to evaluate the comparative distribution, correlation, and apportionment of selected elements-aluminum (Al), calcium (Ca), cadmium (Cd), potassium (K), magnesium (Mg), sodium (Na), and lead (Pb)-in the blood samples of male kidney failure patients (KFP) and healthy subjects of age ranged 30-60 years. The blood samples were digested with nitric acid and perchloric acid mixture (2:1), followed by the quantification of elements by atomic absorption spectrometry. The concentration of essential elements in blood samples of KFP were found in the range of Ca (97-125), Mg (18-36), Na (2971-3685), and K (177-270) mg/L while, the levels of Al, Cd, and Pb were found in the range of (475-1275), (0.9-9.9), and (211-623) μg/L, respectively. In the healthy referents, concentration of electrolytes in blood samples was lower than KFP, but difference was not significant (p > 0.05). While the levels of toxic elements in blood samples of referents were three- to sixfold lower than KFP (p < 0.01). Principal component analysis (PCA) and cluster analysis (CA) of the element data manifested diverse apportionment of the selected elements in the blood sample of the KFP compared with the healthy counterparts.

Total metal concentrations in serum of dialysis patients and fractionation of Cu, Rb, Al, Fe and Zn in spent continuous ambulatory peritoneal dialysis fluids

Total metal concentrations were determined in the serum of 12 continuous ambulatory peritoneal dialysis (CAPD) patients and in fresh and spent CAPD fluids by electrothermal and flame atomic absorption spectrometry (ETAAS, FAAS). Concentrations of Cu in serum of CAPD patients ranged from 720 to 1780 ngcm(-3), Rb from 128 to 346 ngcm(-3), Al from 10 to 72 ngcm(-3), Fe from 800 to 2300 ngcm(-3) and Zn from 659 to 1310 ngcm(-3). The accuracy of the analytical procedure was checked by the analysis of the reference material Seronomtrade mark, Trace Elements in Serum. Good agreement between the certified and determined values was obtained for Al, Cu, Fe and Zn. The data on the total metal concentrations in CAPD fluids indicated that during CAPD fluid exchange the losses of Cu from 5.0 to 35 ngcm(-3), of Rb from 50 to 110 ngcm(-3) and of Al from 3.0 to 14.0 ngcm(-3) occurred through the peritoneal membrane. Although fresh CAPD fluids contained traces of Fe (3.0-5.0 ngcm(-3)), the transfer of this element took place through the peritoneal membrane into spent CAPD fluid (13.0-38.0 ngcm(-3)). Zn concentrations were in general lower in spent (20.0-80 ngcm(-3)) than in fresh CAPD fluids ( approximately 100 ngcm(-3)). To follow the mechanisms of the transfer of trace elements through the peritoneal membrane of CAPD patients, fractionation of metals was carried out in spent CAPD fluids by size exclusion chromatography with UV and AAS detection, applying Superdex HR 10/30 column. The chromatographic run was followed at 278 nm and separated metal species also determined 'off line' in 1 cm(3) fractions by ETAAS or FAAS. From the UV chromatograms and AAS analysis of trace elements in the separated fractions it was demonstrated that Cu, Al, Fe and Zn were bound to proteins and only partially to low molecular weight (LMW) species, while Rb was associated exclusively with LMW species. For characterisation of the high molecular weight (HMW) binding proteins, fractions containing trace elements were subjected to SDS-PAGE electrophoresis. Al and Fe were presumably bound to transferrin, but due to its low concentration in spent CAPD fluids, it was not possible to confirm its presence in the separated fractions. About 10% of Al and 15% of Fe corresponded to LMW species. A fraction of HMW proteins of Cu in spent CAPD fluids was most probably bound to albumin and Zn to albumin and globulins. About 50% of Cu and Zn existed in LMW proteins, while Zn was also found partially in ionic form.

Trace element status of chronic renal patients undergoing hemodialysis

The purpose of this study was to examine the status of trace elements (Cu, Zn, and Fe) and minerals (Mg, K, Na, and Cl) and the level of biochemical parameters (urea, creatinine, total protein, albumin, and glucose) in hemodialysis (HD) patients. This study included 30 HD patients (25 men and 5 women) aged 52.12 +/- 3.13 years and 30 healthy subjects (23 men and 7 women) aged 51.64 +/- 2.22 years. This study investigated the status of trace elements and minerals in HD patients. It was found that the total HD patients (before and after dialysis) had statistically lower Zn and albumin in the after-dialysis group K and Cl levels and higher Mg, creatinine, and urea in the before-dialysis group K and in the after-dialysis group glucose levels than those of the controls. It was determined that the results might be helpful in monitoring patients with renal failure in terms of insufficiency or excess of trace elements and minerals. There was positive correlation for Mg-K (r = 0.64; p = 0.001), creatinine-urea (r = 0.59; p = 0.001), K-urea (r = 0.56; p = 0.001), K-creatinine (r = 0.52; p = 0.003), Mg-creatinine (r = 0.47; p = 0.008), Zn-albumin (r = 0.40; p = 0.028), and Zn-creatinine (r = 0.40; p = 0.031) in the before-dialysis session. There was also positive correlation for creatinine-urea (r = 0.56; p = 0.001), K-urea (r = 0.39; p = 0.035), and Mg-creatinine (r = 0.38; p = 0.041) in the after-analysis session. As a result of the analysis of regression between serum levels of albumin and zinc in total HD patients, the use of the level of albumin might be a suitable choice in determining zinc deficiency resulting from the decrease in the level of zinc in parallel to that of albumin. The results also suggest that the relationship between creatinine and K, Mg, and Zn could be ascribed to the loss of renal function.

Long-term changes of plasma trace element concentrations in chronic hemodialysis patients

BACKGROUND

Hemodialysis (HD) patients are at risk of developing trace element imbalances.

METHODS

The 12 trace elements Cd, Co, Cs, Cu, La, Mg, Mo, Pb, Rb, Sr, Tl and Zn were determined in the plasma (n = 52) of 6 chronic HD patients before and after HD sessions by inductively coupled plasma mass spectrometry. Plasma trace element concentrations were monitored for 6 months. Baseline data have been compared to the concentrations at the end of the observation period to identify a potential reduction or accumulation of trace elements in HD patients.

RESULTS

Plasma Cd, Co and Pb levels were about 10 times higher than in healthy adults. Concentrations of Co and Pb increased during HD sessions, whereas plasma Co and Cd increased during the study period of 6 months. Plasma Cs, Mg, Mo and Rb continuously decreased in all patients. For plasma Cu and Zn, a statistically significant rise of their plasma concentrations during HD and during the period of 6 months could be established. Concentrations of La and Tl did not change distinctly.

CONCLUSION

This study revealed that plasma trace element concentrations in HD patients are distinctly different compared to that of healthy adults. Elements such as Cs, Mg, Mo and Rb are reduced and Cd, Co and Pb are accumulated in HD patients. Further studies are needed to elucidate the clinical impact of these trace element imbalances.