Trace elements in end-stage renal disease. 2. Clinical implication of trace elements

Effects of Zinc Acetate Hydrate Supplementation on Renal Anemia with Hypozincemia in Hemodialysis Patients

INTRODUCTION AND AIMS

This study examined whether zinc supplementation with zinc acetate hydrate improved renal anemia with hypozincemia in patients undergoing hemodialysis.

METHODS

The study participants included 21 patients undergoing hemodialysis who presented with a serum zinc level < 60 mg/dL and who were administered zinc acetate hydrate at 50 mg (reduced to 25 mg, as appropriate) for 6 months. Patients with a hemorrhagic lesion, acute-phase disease (pneumonia or cardiac failure), or hematologic disease and those whose treatment was switched from peritoneal dialysis to hemodialysis were excluded. The changes in the erythropoietin resistance index (ERI) before and after zinc acetate hydrate administration were examined. ERI was defined as the dose (IU) of erythropoiesis-stimulating agent (ESA)/week/body weight (kg)/hemoglobin content (g/dL). The differences between the two groups were analyzed using the Wilcoxon signed rank sum test, and p < 0.05 was considered statistically significant.

RESULTS

The study participants included 19 men and 2 women aged 41-95 years (mean ± standard deviation (SD): 67.1 ± 13.6). The changes in the values of parameters measured before and after zinc acetate hydrate administration were as follows: Blood Hb did not change significantly, from 10.0-13.6 g/dL (11.5 ± 1.0 g/dL) to 10.2-12.4 g/dL (11.4 ± 0.7 g/dL); serum zinc concentration significantly increased, from 33.0-59.0 mg/dL μg/dL (52.4 ± 7.6 mg/dL μg/dL) to 57.0-124.0 mg/dL μg/dL (84.1 ± 16.3 mg/dL μg/dL; p < 0.01); the ESA dose significantly decreased, from 0-12,000 IU/week (5630 ± 3351 IU/week) to 0-9000 IU/week (4428 ± 2779; p = 0.04); and ERI significantly decreased, from 0.0-18.2 (8.1 ± 5.1) to 0.0-16.0 (6.3 ± 4.3; p = 0.04).

CONCLUSIONS

Zinc supplementation increased the serum zinc concentration and significantly reduced the ESA dose and ERI, suggesting that a correction of hypozincemia contributes to lessening renal anemia in these patients.

Breast-Milk Rubidium and Other Trace Elements are Associated with Neurocognitive Development in Infants at Age of 8 Months

BACKGROUND

Trace elements may affect neurodevelopment. There is a lack of data on breast-milk rubidium (Rb) in relation to neurodevelopment in infants. The associations of copper (Cu), zinc (Zn) and strontium (Sr) with neurodevelopment in infants remain uncertain.

OBJECTIVES

We sought to evaluate the associations of breast-milk Rb (primary exposure), Cu, Zn, and Sr with neurodevelopment in infants at age 8 months.

METHODS

The study cohort included 117 breastfed infants. Breast-milk samples were collected at 42 days and 8 months postpartum. Breast-milk Rb, Zn, Cu, and Sr were measured by inductively coupled plasma mass spectrometer. Neurodevelopment was assessed at age 8 months. The primary outcomes were attention and working memory scores, as evaluated by the A-not-B task. Other outcomes included the Mental Development Index (MDI) and Psychomotor Development Index (PDI) as evaluated by the Bayley Scale of Infant Development III. Generalized linear models and restricted cubic spline regression were used to assess the associations between trace elements and neurodevelopment indices. Bonferroni correction was conducted on all data presented.

RESULTS

A nonlinear association was observed between breast-milk Rb at 42 days and infant's attention at age 8 months (nonlinearity P = 0.037). Positive associations were observed with infant MDI scores and breast-milk Rb at 42 days (β = 4.46; P = 0.06) and 8 months (β = 3.79; P = 0.009) postpartum. Breast-milk Zn at 42 days was positively associated with infant's attention (β = 0.31; P = 0.039). Sr at 42 days was positively correlated with attention (β = 0.18; P = 0.043) and MDI scores (β = 2.18; P = 0.015) at 8 months. Inverted U-shape associations were observed for breast-milk Cu at 42 days with infant attention and PDI scores. All associations were not significant after correction for multiple tests.

CONCLUSIONS

Our data suggest that Rb, Zn, Cu, and Sr in breast milk at certain concentrations are associated with neurodevelopment in breastfed infants. Further studies are warranted to validate the findings.

Investigation of the Relationship Between IL-18 (- 607 C/A), IL-18 (- 137 G/C), and MMP-2 (- 1306 C/T) Gene Variations and Serum Copper and Zinc Levels in Patients Diagnosed with Chronic Renal Failure

The aim of this study is to investigate the relationship between IL-18 (- 607 C/A), IL-18 (- 137 G/C), and MMP-2 (- 1306 C/T) gene variations and serum trace element levels in patients diagnosed with CRF. Genotype distributions of IL-18 (- 607 C/A, - 137 G/C) gene variations were determined by polymerase chain reaction (PCR) method. PCR-restriction fragment length polymorphism (RFLP) methods were used to determine the MMP-2 (- 1306 C/T) gene variation genotype distributions. Serum trace element levels were determined by atomic absorption spectrophotometer method. A significant difference was found between the CRF patient and healthy control groups in terms of genotype distributions of IL-18 (- 607 C/A) and MMP-2 (- 1306 C/T) gene variations (p < 0.05). The significant difference was found between the patient and control groups in terms of serum copper and zinc levels and copper/zinc ratio (p < 0.05). The significant difference was detected between patient and control groups in terms of copper and zinc levels and copper/zinc ratio according to IL-18 (- 607 C/A), IL-18 (- 137 G/C), and MMP-2 (- 1306 C/T) gene variations and genotype distributions (p < 0.05). In addition, significant difference was determined in terms of serum copper and zinc levels and copper/zinc ratio according to haplotypes of IL-18 (- 607 C/A), IL-18 (- 137 G/C), and MMP-2 (- 1306 C/T) gene variations between patient and control groups (p < 0.05). In conclusion, evaluation of IL-18 (- 607 C/A, - 137 G/C) and MMP-2 (- 1306 C/T) gene variations and serum trace element levels together is extremely important in terms of obtaining important biomarkers in CRF early diagnosis and progression.

Zinc Deficiency in Men Over 50 and Its Implications in Prostate Disorders

Research has been consistently showing the role of zinc (Zn) in prostate function. In this article, we review the current literature on the anatomy and main functions of the prostate, highlighting the role of zinc. In particular, we will review the etiology of benign prostate enlargement (BPH), its prevalence in men over 50, the likelihood of BPH becoming prostate cancer (PCa), and explain the relationship of zinc and apoptosis in the prostate cells and the implications for BPH and PCa. We present a model that explains how endogenous factors provoke excretion of zinc or limit zinc absorption, and how exogenous factors like nutrition and drugs regularly used in men over 50 can significantly decrease zinc status and thereby increase the risk of BPH. Finally, we explain how Zn amino acid (AA) complexes may be capable of avoiding antagonists and inhibitors of zinc absorption, thereby increasing the bioavailability of zinc for the necessary biological processes in the prostate.

Tc-99m TRODAT-1 SPECT is a Potential Biomarker for Restless Leg Syndrome in Patients with End-Stage

Rationales: Restless leg syndrome (RLS) is a common complication in patients with end-stage renal disease (ESRD). However, there is a lack of biomarkers linking uremic RLS to dopaminergic neurons. Previous studies demonstrated that Tc-99m TRODAT-1 SPECT was a biomarker for RLS but the correlation between the physiologic parameter was lacking. Methods: Overall, 32 patients were enrolled in the study and divided into the following 3 groups: (1) control (n = 13), (2) ESRD without RLS (n = 8) and (3) ESRD with RLS (n = 11). All patients had a clinical diagnosis of RLS and received Tc-99m TRODAT-1 SPECT. A subgroup analysis was performed to compare differences between the control and ESRD with RLS groups. Tc-99m TRODAT-1 SPECT was performed and activities in the striatum and occipital areas were measured using manually delineated regions of interest (ROIs) by an experienced nuclear medicine radiologist who was blinded to clinical data. Results: The total ratio of Tc-99m TRODAT SPECT was lower in the ESRD with RLS group (p = 0.046). The uptake ratio of TRODAT negatively correlated with serum parathyroid hormone (r = −0.577, p = 0.015) and ferritin (r = −0.464, p = 0.039) concentrations. However, the uptake positively correlated with the hemoglobin concentration (r = 0.531, p = 0.011). The sensitivity and specificity of the total TRODAT ratio for predicting RLS in the overall population were 95.0% and 67.7%, respectively, at a cutoff value of 0.980 (area under the curve of receiver operating characteristic curve was 0.767, p = 0.024). Conclusion: In patients with ESRD and RLS, Tc-99m TRODAT might be a potential biomarker. Dysregulated hemoglobin, serum parathyroid hormone and serum ferritin concentrations might influence the uptake of the TRODAT ratio.

Selenium Metabolism in Patients on Continuous Ambulatory Peritoneal Dialysis

Background

Selenium is an essential trace element for living organisms. In many publications, researchers express concern about a possible Se deficiency in patients with end-stage chronic renal failure (ESCRF) undergoing continuous ambulatory peritoneal dialysis (CAPD). However, in a number of published articles, the data provide no evidence that patients under CAPD develop Se deficiency.

Objective

We investigated Se metabolism in ESCRF patients on CAPD.

Setting

The study was carried out at the Department of Propaedeutic Surgery, Athens University; the Laboratory for Material Analysis of the Nuclear Physics Institute; and the State General Hospital, Athens, Greece.

Patients and Methods

The study group included 24 patients on CAPD treatment, 14 ESCRF patients, and 17 healthy controls. We measured the Se and Fe content of serum, blood, and erythrocytes. We also measured hematocrit, serum total proteins and albumins, and Se in dialysate effluent.

Results

As compared with healthy subjects, the ESCRF and CAPD patients exhibited reduced serum concentrations of Se. However, considering the difference in hematocrit values, the total serum-transported Se per liter of blood was close to normal. Erythrocyte Se proved normal for both groups. The measured Se in the spent effluent indicates that patients under CAPD receive approximately 100 μg Se from their daily diet, as normal subjects do. The Se measurement data from the effluent indicate that 90% of the Se carried by the serum is bound to albumins and that only the remaining 10% is in the form of low molecular weight selenate, free to pass the peritoneal membrane. Of the 24 CAPD patients studied, 4 patients (all women) showed extremely low Se serum levels. Data suggest that those low levels are more likely due to the significantly lower serum albumin levels in the 4 patients than to an insufficient dietary intake.

Conclusions

Data from the present experimental work suggest that patients undergoing CAPD receive the necessary quantities of Se from their regular diet. The data contradict statements in the relevant literature that CAPD patients develop Se deficiency.

Simultaneous multielement analysis by ICP-MS with simple whole blood sample dilution and its application to uremic patients undergoing long-term hemodialysis

Few studies were reported on trace elements' alterations in uremic patients undergoing long-term (>24 months) hemodialysis (HD), especially by using the whole blood as the biological fluid for the measuring purpose. Our objective was to develop an improved micro-sampling inductively coupled plasma-mass spectrometry (ICP-MS) method to determine the levels of Ca, Mg, Cu, Zn, Fe, Mn, Se and Pb in uremic patients receiving long-term HD. A ICP-MS method with a modified whole blood sample preparation procedure with small volumes was established and applied for the simultaneous quantification of the various elements in uremic patients undergoing long-term HD. 124 eligible uremic patients receiving long-term HD (75 males and 49 females) and 77 healthy subjects (54 males and 23 females) were recruited and Ca, Mg, Cu, Zn, Fe, Mn, Se and Pb levels were further determined. Our results revealed that uremic patients with HD had significantly higher blood levels of Ca, Mg, Zn and Pb and lower Cu, Fe, Se and Mn concentrations than healthy controls. In conclusion, a reproducible and reliable ICP-MS method using minimal whole blood sample volume (50 μL) with a simple dilution-based preparation procedure was successfully improved, validated and applied. Uremic patients undergoing long-term HD might be at increased risk of some essential trace elements deficiency (especially for Cu, Fe and Se) or toxic trace element excess (Pb) in respect to healthy subjects. Monitoring of blood levels and supplementation of some trace elements may be indicated in uremic patients undergoing long-term HD.

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.

Concentrations of Trace Elements and Clinical Outcomes in Hemodialysis Patients: A Prospective Cohort Study

BACKGROUND AND OBJECTIVES

Deficiency of essential trace elements and excess of potentially toxic trace elements are common in patients on hemodialysis. Whether these abnormalities are associated with poor outcomes is unknown but worth investigating, because they are potentially treatable.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We did a prospective longitudinal study of 1278 patients on incident hemodialysis, assessing blood concentrations of 25 trace elements at baseline. We used adjusted logistic regression to evaluate the association between trace element status and four outcomes (death, cardiovascular events, systemic infection, and hospitalization). A priori hypotheses concerned (1) deficiency of zinc, selenium, and manganese and (2) excess of lead, arsenic, and mercury. Concentrations of the other 19 elements were tested in hypothesis-generating analyses.

RESULTS

Over 2 years of follow-up, 260 (20%) patients died, 285 (24%) experienced a cardiovascular event, 117 (10%) were hospitalized for systemic infection, and 928 (77%) were hospitalized for any cause. Lower concentrations of zinc or manganese and higher concentrations of lead, arsenic, or mercury were not independently associated with higher risk of clinical outcomes. Lower concentrations of selenium were strongly and independently associated with death (odds ratio, 0.86 per decile; 99.2% confidence interval, 0.80 to 0.93) and all-cause hospitalization (odds ratio, 0.92 per decile; 99.2% confidence interval, 0.86 to 0.98). In exploratory analyses, higher copper concentrations were significantly associated with higher risk of death (odds ratio, 1.07 per decile; 99.2% confidence interval, 1.00 to 1.15), and cadmium levels in the highest decile were associated with higher risk of death (odds ratio, 1.89; 99.2% confidence interval, 1.06 to 3.38).

CONCLUSIONS

Lower levels of zinc or manganese and higher concentrations of lead, arsenic, or mercury were not associated with higher risk of clinical outcomes, but lower concentrations of selenium were strongly and independently associated with the risks of death and hospitalization.

Concentrations of Trace Elements in Hemodialysis Patients: A Prospective Cohort Study

BACKGROUND

Low concentrations and excessive concentrations of trace elements have been commonly reported in hemodialysis patients, but available studies have several important limitations.

STUDY DESIGN

Random sample of patients drawn from a prospective cohort.

SETTING & PARTICIPANTS

198 incident hemodialysis patients treated in 3 Canadian centers.

MEASUREMENTS

We used mass spectrometry to measure plasma concentrations of the 25 elements at baseline, 6 months, 1 year, and 2 years following enrollment in the cohort. We focused on low concentrations of zinc, selenium, and manganese and excessive concentrations of lead, arsenic, and mercury; low and excessive concentrations of the other 19 trace elements were treated as exploratory analyses. Low and excessive concentrations were based on the 5th and 95th percentile plasma concentrations from healthy reference populations.

RESULTS

At all 4 occasions, low zinc, selenium, and manganese concentrations were uncommon in study participants (≤5.1%, ≤1.8%, and ≤0.9% for zinc, selenium, and manganese, respectively) and a substantial proportion of participants had concentrations that exceeded the 95th percentile (≥65.2%, ≥74.2%, and ≥19.7%, respectively). Almost all participants had plasma lead concentrations above the 95th percentile at all time points. The proportion of participants with plasma arsenic concentrations exceeding the 95th percentile was relatively constant over time (9.1%-9.8%); the proportion with plasma mercury concentrations that exceeded the 95th percentile varied between 15.2% and 29.3%. Low arsenic, platinum, tungsten, and beryllium concentrations were common (>50%), as were excessive cobalt, manganese, zinc, vanadium, cadmium, selenium, barium, antimony, nickel, molybdenum, lead, and chromium concentrations.

CONCLUSIONS

There was no evidence that low zinc, selenium, or manganese concentrations exist in most contemporary Canadian hemodialysis patients. Some patients have excessive plasma arsenic and mercury concentrations, and excessive lead concentrations were common. These findings require further investigation.

Trace Elements in Chronic Haemodialysis Patients and Healthy Individuals-A Comparative Study

INTRODUCTION

End Stage Renal Disease (ESRD) patients despite receiving adequate Haemodialysis (HD) develop significant risk of Cardiovascular Disease (CVD). Abnormality in levels of trace elements may potentiate vascular injury by producing sustained inflammation and endothelial dysfunction. Hence, the present study was undertaken to evaluate the levels of trace elements in patients receiving HD.

AIM

To study the blood levels of arsenic, cadmium, mercury, lead, chromium, barium, cobalt, caesium and selenium among ESRD patients undergoing HD and compare it with healthy individuals.

MATERIALS AND METHODS

It was a cross-sectional, comparative study done in a tertiary care center. About 40 established ESRD patients aged above 18 years, belonging to both sexes, undergoing chronic HD for more than six months were enrolled as Group A (Cases). Patients who had history of smoking and occupational exposure to heavy metals were excluded from the study. About 40 age and sex matched apparently healthy individuals attending health check-up were enrolled as Group B (Controls). Participants of this group had normal e-GFR by Modification of Diet in Renal Disease (MDRD) equation. About 5ml of fasting venous blood sample was obtained from both groups and analyzed for trace elements. Chi-square/Fisher's-exact test was used for comparing ratios. A p-value of <0.05 was considered statistically significant.

RESULTS

In the present study, the mean blood levels of arsenic, cadmium, chromium and cobalt was found to be significantly higher in Group A as compared to Group B with all these parameters attaining a p-value of <0.001. Similarly, the mean blood levels of lead and caesium was high in Group A with a p-value of 0.001 each. The blood levels of mercury and barium did not vary significantly between both the groups with p=0.656 and 0.096 respectively. The blood levels of anti-oxidant selenium was lower in Group A, but did not attain statistical significance (p=0.217).

CONCLUSION

The mean blood levels of toxic trace elements were significantly elevated with a simultaneous reduction in essential trace elements in patients receiving HD, which probably may contribute to an increase in CVD.

Variation of trace element concentrations in patients undergoing hemodialysis in the north of Spain

BACKGROUND

Trace elements are essential substances for the proper physiological and biochemical functioning of the organism. Hemodialysis patients are potentially at risk of deficiency or excess of these elements. The application of inductively coupled plasma mass spectrometry (ICP-MS) allows the simultaneous quantification of very small amounts of multiple trace elements. The aim was to measure the serum concentration of copper (Cu), zinc (Zn), selenium (Se), and nickel (Ni), and the whole blood concentration of arsenic (As), lead (Pb), and manganese (Mn), in patients undergoing hemodialysis as well as in controls.

METHODS

The study was carried out in 57 hemodialysis patients compared with 57 controls with normal renal function. Serum and whole blood samples from the dialysis group were collected before and after hemodialysis sessions and Cu, Zn, Se, Ni, As, Pb and Mn levels were determined using ICP-MS.

RESULTS

Hemodialysis patients showed significantly lower blood levels of Cu, Zn and Se than controls (p < 0.001) and higher concentrations of Ni, As and Pb (p < 0.0001). The levels of Mn were similar in both groups. After performing hemodialysis, Cu, Zn, Se and Ni concentrations were significantly higher than the pre-hemodialysis levels (p < 0.0001). However, the concentration of As decreased (p < 0.0001) and Pb and Mn levels were not significantly altered after the dialysis session.

CONCLUSION

Hemodialysis patients are at increased risk of trace elements deficiency (especially for Zn and Se) or excess (Ni) in respect to healthy subjects. Monitoring of blood levels and supplementation of some trace elements may be indicated in patients undergoing hemodialysis.

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.

[Importance of selenium homeostasis in chronic and end-stage kidney diseases]

Selenium is an essential trace element for the human body with a significant antioxidant effect. Selenium deficiency and excess are both detrimental for proper functioning of the human body. The possible association between selenium deficiency and acute or chronic renal disease, along with their complications has been less intensively investigated, however, there are firm data showing that selenium deficiency and renal failure increase the risk of both coronary artery disease and total mortality. Further studies revealed that selenium deficiency increases the risk of death due to infection in patients treated with hemodialysis through dysfunction of the immune system. However, there are no data whether the imbalance of selenium metabolism, especially selenium deficiency, could cause chronic kidney disease or renal failure. As far as results of selenium measurements, there is convincing evidence that protein loss and renal replacement treatment reduce serum selenium levels. Despite some contradictory results obtained from various studies regarding selenium deficiency in chronic kidney diseases, it seems that selenium supplementation may be beneficial in many patients with severe or end-stage kidney disease including those treated with dialysis.

Disturbances of trace element metabolism in ESRD patients receiving hemodialysis and hemodiafiltration

Introduction

Accumulation of trace elements occurs in conditions of decreased kidney function. In some conditions, increased trace elements can have toxic features. On the other hand, studies are showing that concentration of some trace elements could be decreased in ERSD patients as well. The most important factor affecting trace element concentration in ERSD patients is the degree of renal failure and the usage of replacement therapy.

Materials and methods

We analyzed the trace elements’ (boron, aluminum, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, rubidium, strontium, cadmium, cesium, barium and lead) concentration in the whole blood of 41 ESRD patients who were treated with hemodialysis and hemodiafiltration and also of 61 healthy blood donors. In addition, comparison of trace element blood levels of patients receiving hemodialysis and hemofiltration was carried out. Whole blood trace element concentration was determined using inductive coupled plasma mass-spectrometry (ICPMS).

Results

Levels of boron, aluminum, vanadium, chromium, manganese, zinc, strontium, cadmium, barium and lead were significantly increased in ESRD patients. Significantly decreased levels were observed for nickel, arsenic, selenium and rubidium. Blood levels of cobalt, copper, cadmium and lead in hemodialysis patients were significantly higher compared to patients receiving hemodiafiltration.

Conclusions

ESRD is accompanied with serious and multidirectional changes of trace element blood levels. The highest degree of blood level increases were observed for nonessential and toxic trace elements. Disorders of essential trace elements were manifested in a minor degree. Besides this, there were observed differences of trace element concentrations between ESRD patients receiving hemodialysis and hemo-diafiltration.

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.

Blood Arsenic and Cadmium Concentrations in End-Stage Renal Disease Patients who were on Maintenance Haemodialysis

BACKGROUND

In India, there is a rising burden of chronic diseases like hypertension and diabetes. It has been estimated that 25-40% of these patients are likely to develop chronic kidney disease (CKD), with a significant percentage requiring renal replacement therapy. Haemodialysis is the most common method which is used to treat advanced and permanent kidney failure. Derangements in the metabolism of several toxic and trace elements such as antimony, arsenic cadmium, molybdenum, nickel, and selenium have been reported for several decades in patients with chronically reduced renal functions. Overall, the available literature suggests that the blood levels of some elements such as cadmium, chromium, fluorine, iodine, lead, or vanadium are high in end-stage renal disease (ESRD).

AIM AND OBJECTIVES

Our aim was to study the levels of blood arsenic and cadmium in ESRD patients who were on maintenance haemodialysis (MHD), and to study whether there was any relationship between their concentrations and the duration of the MHD.

METHODS

The blood lead levels were determined in 50 healthy subjects with normal renal functions and in 50 patients with ESRD, who were on MHD. None of them had any history of smoking or any industrial exposure.

RESULTS

The results of the study revealed that the blood arsenic and cadmium concentrations were higher in the ESRD patients who were on MHD than in the healthy adults. The blood arsenic and cadmium concentrations were found to increase with the duration of the MHD.

CONCLUSION

The mild increase in the blood arsenic and cadmium concentrations, with an increase in the duration of the MHD in the study population, may be viewed in the wider context, that a prolonged exposure to arsenic and cadmium, even at low levels, may result in renal damage and/or progression of an already existing CKD.

Trace element status in hemodialysis patients

Patients with chronic kidney disease undergoing hemodialysis (HD) are potentially at risk of deficiency and excess of trace elements. HD exposes patients to large volumes of water (>120 l/week) in the form of dialysate. Although levels of certain ions (such as potassium and calcium) are carefully regulated in dialysate, many others are measured infrequently, if ever. As a result, substances in lower concentrations in the dialysis may be leached from the body. Conversely, toxic trace elements present in water but not in blood may accumulate and cause toxicity. Given that essential trace elements play key roles in multiple biological systems including immunological defense against oxidation and infection, it has been hypothesized that the increased morbidity and mortality seen in HD patients may in part be due to the imbalance of trace elements that has not been recognized. A recent systematic review has shown that compared with healthy controls, HD patients have significantly lower blood levels of zinc, manganese, and selenium, while blood levels of lead are likely to accumulate. Other trace elements, such as mercury and arsenic, are biologically plausible causes of excess mortality in dialysis patients, but available evidence is inconclusive as to whether they consistently accumulate in this population. Whether altered trace element levels are potentially reversible causes of adverse clinical outcomes in dialysis patients remains to be determined. This review highlights key issues related to this hypothesis, with special emphasis on zinc, manganese, selenium, lead, mercury, and arsenic.

Selenium, lead, and cadmium levels in renal failure patients in China

Whole blood and serum samples of Chinese stable chronic renal failure (CRF) patients (n = 81), hemodialysis patients (n = 135), posttransplant patients (n = 60), and subjects with normal renal function (NRF; N = 42) were collected, as well as water and dialysate samples from five dialysis centers. The concentration of selenium (Se), lead (Pb), and cadmium (Cd) was measured by atomic absorption spectrometry. The mean serum Se levels in patients with different degrees of renal failure were significantly lower than those of subjects with NRF (p < 0.01). Pb levels were not increased in renal failure patients, while the Cd levels in patients with various degrees of renal failure were higher than in subjects with NRF (p < 0.05). After correcting the results of Pb and Cd for hematocrit (Hct) however, Pb levels of dialysis patients were also increased. In the dialysis population under study, blood Pb and Cd levels were closely related to the time on dialysis, while contamination of the final dialysate may also contribute to the increased blood Cd and to a less extent Pb levels. Correction for Hct may be recommended to accurately compare blood Pb and Cd levels in dialysis patients and CRF patients with varying degrees of anemia to those of subjects with NRF.

Trace elements in hemodialysis patients: a systematic review and meta-analysis

BACKGROUND

Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.

METHODS

All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.

RESULTS

We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.

CONCLUSION

Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.

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.

Selenium status indices, laboratory data, and selected biochemical parameters in end-stage renal disease patients

We investigated the relations between selenium status (SeS) parameters, indexes of nutrition, erythropoiesis, and uremic toxemia, serum electrolytes, and other biochemical markers in end-stage renal disease (ESRD) patients, as no multivariate statistical analysis concerning all of these parameters was performed so far. SeS was evaluated by plasma Se concentration (plSe) and glutathione peroxidase (plGSHPx) activity in 69 uremic patients treated with hemodialysis (HD) and 40 healthy controls. The hierarchical multivariate partial least squares model (PLS2) was employed to establish data structure and correlations between parameters investigated. plSe and plGSHPx activity were significantly lower in patients when compared with controls (p=0.000). plSe was positively associated with indexes of erythropoiesis and nutritional status, as well as serum electrolytes and parameters of uremic toxemia. plGSHPx was inversely dependent on the pair of parameters: intact parathyroid hormone (iPTH) and aluminum plasma concentration (Al). We conclude that (1) ESRD strongly decreases selenium status and (2) the PLS2 approach revealed the existence of significant interactions among plSe, plGSHPx, and selected biochemical parameters or groups of such parameters; some of these associations need further studies to be clarified.

Possible linkages between lignite aquifers, pathogenic microbes, and renal pelvic cancer in northwestern Louisiana, USA

In May and September, 2002, 14 private residential drinking water wells, one dewatering well at a lignite mine, eight surface water sites, and lignite from an active coal mine were sampled in five Parishes of northwestern Louisiana, USA. Using a geographic information system (GIS), wells were selected that were likely to draw water that had been in contact with lignite; control wells were located in areas devoid of lignite deposits. Well water samples were analyzed for pH, conductivity, organic compounds, and nutrient and anion concentrations. All samples were further tested for presence of fungi (cultures maintained for up to 28 days and colonies counted and identified microscopically) and for metal and trace element concentration by inductively-coupled plasma mass spectrometry and atomic emission spectrometry. Surface water samples were tested for dissolved oxygen and presence of pathogenic leptospiral bacteria. The Spearman correlation method was used to assess the association between the endpoints for these field/laboratory analyses and incidence of cancer of the renal pelvis (RPC) based on data obtained from the Louisiana Tumor Registry for the five Parishes included in the study. Significant associations were revealed between the cancer rate and the presence in drinking water of organic compounds, the fungi Zygomycetes, the nutrients PO(4) and NH(3), and 13 chemical elements. Presence of human pathogenic leptospires was detected in four out of eight (50%) of the surface water sites sampled. The present study of a stable rural population examined possible linkages between aquifers containing chemically reactive lignite deposits, hydrologic conditions favorable to the leaching and transport of toxic organic compounds from the lignite into the groundwater, possible microbial contamination, and RPC risk.

Serum zinc and copper levels in children with chronic renal failure

We evaluated changes in serum zinc (Zn) and copper (Cu) levels in two groups of children with chronic renal failure (CRF)--children with CRF who were on regular hemodialysis (Group 1, n=40) and children with CRF who were on conservative management (Group 2, n=31)--and in one group of healthy children (Group 3, n=30). All of the participants in the study were between 5-18 years old, and the composition of the three groups was almost identical with respect to age and sex. The length of time the children in Group 1 had been on hemodialysis varied between 3 and 52 months (mean: 20.97+/-14.8 months). To evaluate the impact of the duration of dialysis on serum levels of Zn, we further sub-divided Group 1 patients into two subgroups: Subgroup A patients (n=20) had been on hemodialysis therapy for less than 18 months (mean: 8.85+/-4.83 months); Subgroup B patients (n=20) had been on hemodialysis therapy for longer than 18 months (mean: 33.1+/-10.86 months). The PIXE (proton-induced X-ray emission) was used for measuring the trace elements.

RESULTS

The mean serum level of Zn was lower in the Group 1 (hemodialysis group) children than in the children of Group 2 (on conservative management) and group 3 (healthy children) (p<0.001), but the difference was not significant between Groups 2 and 3. No significant differences in serum levels of Cu were found among the three groups. The serum level of Zn was lower in Subgroup B than in Subgroup A (p<0.001). The correlation test showed that there was an inverse linear relation between the length of time the child was on the hemodialysis regimen and serum Zn levels.

CONCLUSION

Chronic hemodialysis may lead to abnormalities in the serum levels of some trace elements in children with CRF that increase in severity with increasing duration of hemodialysis. Deficiencies of these trace elements--zinc in particular--may contribute to various conditions and symptoms in children undergoing chronic hemodialysis.

Copper, selenium, zinc, and thiamine balances during continuous venovenous hemodiafiltration in critically ill patients

BACKGROUND

Acute renal failure is a serious complication in critically ill patients and frequently requires renal replacement therapy, which alters trace element and vitamin metabolism.

OBJECTIVE

The objective was to study trace element balances during continuous renal replacement therapy (CRRT) in intensive care patients.

DESIGN

In a prospective randomized crossover trial, patients with acute renal failure received CRRT with either sodium bicarbonate (Bic) or sodium lactate (Lac) as a buffering agent over 2 consecutive 24-h periods. Copper, selenium, zinc, and thiamine were measured with highly sensitive analytic methods in plasma, replacement solutions, and effluent during 8-h periods. Balances were calculated as the difference between fluids administered and effluent losses and were compared with the recommended intakes (RI) from parenteral nutrition.

RESULTS

Nineteen sessions were conducted in 11 patients aged 65 +/- 10 y. Baseline plasma concentrations of copper were normal, whereas those of selenium and zinc were below reference ranges; glutathione peroxidase was in the lower range of normal. The replacement solutions contained no detectable copper, 0.01 micromol Se/L (Bic and Lac), and 1.42 (Bic) and 0.85 (Lac) micromol Zn/L. Micronutrients were detectable in all effluents, and losses were stable in each patient; no significant differences were found between the Bic and Lac groups. The 24-h balances were negative for selenium (-0.97 micromol, or 2 times the daily RI), copper (-6.54 micromol, or 0.3 times the daily RI), and thiamine (-4.12 mg, or 1.5 times the RI) and modestly positive for zinc (20.7 micromol, or 0.2 times the RI).

CONCLUSIONS

CRRT results in significant losses and negative balances of selenium, copper, and thiamine, which contribute to low plasma concentrations. Prolonged CRRT is likely to result in selenium and thiamine depletion despite supplementation at recommended amounts.

Zinc levels after iron supplementation in patients with chronic kidney disease

OBJECTIVE

The goal of this study was to evaluate the effects of iron supplementation on zinc distribution in nondialyzed chronic kidney disease (CKD) patients.

DESIGN

Prospective nonrandomized observational study.

SETTING

Outpatients of the Nephrology Division at Federal University of São Paulo.

PATIENTS

Zinc and iron status of 38 nondialyzed patients (63% male; creatinine clearance, 34.5+/-13.3 mL/min/1.73 m2) was evaluated before and after 3 intramuscular injections of 100 mg iron each.

MAIN OUTCOME MEASURES

The following parameters were analyzed: erythrocytes and plasma zinc, zinc protoporphyrin (ZPP), plasma ferritin, transferrin saturation (TFS), and total iron. The patients' diets were analyzed by the Association of Official Analytical Chemists method for macronutrients, and neutron activation analysis was used for iron and zinc concentration determinations.

RESULTS

Ferritin and TFS increased from 86.3+/-67.5 ng/mL to 105.4+/-63.7 ng/mL and from 19.5+/-7.4% to 23.2+/-6.7% (P <.05), respectively, after iron supplementation. Absolute iron deficiency (ferritin <100 microg/L and TFS <20%) was present in 41% of the patients and decreased to 15.7% after iron treatment. In comparison with baseline values (76.4+/-16.7 microg/dL), there were no significant changes in plasma zinc levels, but after supplementation the number of patients with low plasma zinc levels decreased from 46.1% to 23.7% (P =.08). At baseline, erythrocyte zinc was 49.0+/-7.6 microg Zn/gHb, and 76.3% of the patients had high erythrocyte zinc concentration. After iron treatment, erythrocyte zinc decreased to 45.5+/-7.3 microg Zn/gHb (P =.001). No significant change was observed in ZPP concentration. The analysis of the diet showed energy and protein intakes of 26.2+/-7.1 kcal/kg/day and 0.89+/-0.2 g/kg/day, respectively, and a low intake of both iron and zinc.

CONCLUSIONS

This study suggests that iron deficiency may contribute to the inadequate distribution of zinc in patients with CKD and that iron supplementation may decrease the abnormal elevated erythrocyte zinc levels of these patients.

Troubles sexuels chez 78 hémodialysés chroniques marocains de sexe masculin : étude clinique et endocrinienne

PURPOSE

To investigate the correlation between biochemical and endocrine variables with sexual disorders in 78 male patients on chronic hemodialysis at the Ibn Rochd University Hospital (Casablanca-Morocco).

METHODS

Seventy-eight male hemodialysis patients with chronic renal failure were evaluated with regard to their sexual function. All patients answered a personal questionnaire on their sexual activity. Hormone (FSH, LH, prolactin, testosterone, and parathyroid hormone) and zinc and ferritin assays were also performed.

RESULTS

The men reported erection (44.9%), libido (44.9%), ejaculation (26.8%), and orgasm (21.8%) disorders. Gynecomastia was observed in 17.9% of the patients. There was no correlation with weight nor the nature of the causal nephropathy nor with duration of dialysis. Levels of gonadotropins (FSH, LH), prolactin, and parathyroid hormone were elevated. Testosterone levels were low. Ferritinemia was elevated but there was no significant variation in zincemia. There was a negative curvilinear relationship between serum testosterone and sexual disorders, and between gynecomastia and ferritinemia. LH and prolactin levels were positively correlated with gynecomastia.

CONCLUSION

Abnormal hormonal and iron overload could be important factors involved in the complex pathogenesis of sexual dysfunction in chronic renal failure patients undergoning hemodialysis.

Erythrocyte zinc and carbonic anhydrase levels in nondialyzed chronic kidney disease patients

OBJECTIVE

The aim of the present study was to determine the erythrocyte CAI and CAII concentrations in nondialyzed chronic kidney disease patients, and observe the relationship with acidosis, zinc, anemia, and iron supplementation.

METHODS

Erythrocyte CA concentrations were measured in nondialyzed patients (n = 38) using enzyme-linked immunosorbent assays (ELISA). The zinc concentration was determined by atomic absorption spectrophotometer.

RESULTS AND CONCLUSIONS

The CA levels were observed to be increased in the patients. The mean erythrocyte zinc concentration was also high and the levels of zinc in plasma were baseline values. Correlation was found between CAI and erythrocytes Zn (r = 0.46; P = 0.003), but there was no correlation with ferritin or pH and bicarbonate. The CA levels did not change after iron supplementation, but the zinc erythrocyte levels were reduced. It is concluded that the CA erythrocyte concentration in CKD patients is increased but this cannot be explained by iron deficiency or acidosis.

RENAL RESEARCH INSTITUTE SYMPOSIUM: The Implications of Water Quality in Hemodialysis

Water used in dialysis requires additional treatment to minimize patient exposure to potential contaminants that may be present in drinking water. Although standards for the chemical purity of water are in existence and have eliminated many of the problems seen in renal units in the 1970s, some problems remain, and the importance of newer contaminants arising from changes in water treatment at the municipal level are being recognized. Despite this, recent surveys have indicated considerable shortcomings in compliance with chemical standards. The water quality used in the preparation of dialysis fluid also requires minimal bacterial content. Staff working in renal units are frequently unaware of the level of microbiologic contamination in their dialysis fluid arising from the presence of biofilm in the dialysis machines and the water distribution network. Bacterial fragments generated by such biofilms are able to cross the dialysis membrane and stimulate an inflammatory response in the patient. Such inflammation has been implicated in the mortality and morbidity associated with dialysis. The desire to improve treatment outcomes has led to the application of more stringent standards for the microbiologic purity of dialysis fluid and to the introduction of ultraclean dialysis fluid into clinical practice.

Iron and zinc status of patients with chronic renal failure who are not on dialysis

OBJECTIVE

The purpose of this study was to assess the zinc and iron status in patients with chronic renal failure (CRF) who were not receiving dialysis.

DESIGN

Cross-sectional study.

SETTING

Outclinic patients of the Nephrology Division at Federal University of São Paulo.

PATIENTS

This study was performed on 29 stable patients with CRF who were not receiving dialysis.

MAIN OUTCOME MEASURE

The parameters for determining iron and zinc status were transferrin saturation, zinc protoporphyrin, serum ferritin, hematocrit, serum iron, total iron binding capacity, erythrocyte, and plasma zinc levels (measured by atomic absorption spectrophotometry).

RESULTS

The serum ferritin level was reduced to 85.5 +/- 67.1 ng/mL and the zinc protoporphyrin level was high (68 +/- 32.9 micromol/mol heme), serum transferrin saturation was 19.9% +/- 7.85%, mean serum iron level was 66.6 +/- 26.3 microg/dL, and mean total iron binding capacity was 336 +/- 45.7 microg/dL. Absolute iron deficiency was found in 34.5% of the patients. Zinc level in erythrocytes was high (50.0 +/- 7.2 microg/g hemoglobin), whereas plasma zinc was at a borderline level (74 +/- 17.7 microg/dL) when compared with normal values. There were significant correlations among plasma zinc and serum iron and transferrin saturation, zinc erythrocyte, and parameters of iron.

CONCLUSION

These results show that absolute iron deficiency can occur in patients who are not receiving dialysis and that there is an abnormal distribution of zinc levels in these patients. Moreover, a possible relationship between iron deficiency and zinc distribution was observed.