Study of trace elements in patients on haemodialysis

Copper Deficiency: Causes, Manifestations, and Treatment

BACKGROUND

The metabolism of the essential trace element copper remains incompletely understood and, until recently, nearly ignored in acute medicine. Menkes disease was for long the only known copper deficiency condition, but several case reports and investigations conducted over the last 2 decades have shown that deficiency is more frequent than previously suspected, with devastating individual consequences and potential public health consequences. The copper needs in healthy individuals are 0.9 mg/d, which translates to 0.3 mg/d intravenously in parenteral nutrition; the present review aims at gathering actual knowledge.

METHOD AND RESULTS

A review of literature was conducted in PubMed and Cochrane systematic reviews to identify the most recent information about copper deficiency and generate a narrative review. Copper deficiency has hereditary and acquired origins, the latter being the most frequent. Clinical manifestations are nonspecific but affect all organs and systems, particularly the hematologic (anemia) and the neurologic (myeloneuropathy) systems. Deficiency also affects the cardiovascular, cutaneous, and immune systems. Severe copper deficiency due to reduced absorption after bariatric bypass surgery has become frequent.

CONCLUSION

Deficiency is more frequent than previously recognized, probably because of changing nutrition patterns but also because of some treatments that have become very common such as bypass bariatric surgery and, in acute medicine, prolonged continuous renal replacement therapy. The patients may present with severe hematologic and neurologic complications that go untreated because copper deficiency was not considered in the differential diagnosis: These complications often need active intravenous repletion with doses 4-8 times the usual nutrition recommendations.

Clinical factors associated with serum copper levels and potential effect of sevelamer in hemodialysis patients

OBJECTIVE

Copper is an essential mineral nutrient for humans. Serum copper levels of hemodialysis patients are higher than those of healthy subjects, but it remains to be elucidated whether increased serum copper may have harmful effects. In addition, a recent in vitro study has shown that sevelamer can adsorb copper. In the present study, we searched for clinical factors associated with serum copper levels in hemodialysis patients.

METHODS

This cross-sectional study included patients undergoing hemodialysis for more than 6 months. In these patients, we statistically tested associations between serum copper levels and other parameters, including nutritional markers, lipid profiles, oxidative stress, inflammation, and sevelamer administration.

RESULTS

Among 48 patients (male/female = 28:20, age 71 ± 10 years, hemodialysis duration 84 ± 72 months), sevelamer hydrochloride was administered in 39 patients (81.3 %). In univariate analysis, serum copper levels showed significant positive correlations with serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, high-sensitivity C-reactive protein (hs-CRP), and malondialdehyde modified-LDL and negative correlations with plasma total homocysteine levels and the administered dose of sevelamer. In multivariate analysis, serum levels of LDL-cholesterol and hs-CRP were found to be independent determinants of serum copper levels.

CONCLUSION

We found that serum copper levels were independently associated with dyslipidemia and inflammation in hemodialysis patients, but the pathogenic roles of copper remain to be elucidated. In addition, potential effect of sevelamer on serum copper levels should be examined in appropriately designed studies.

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.

Aluminum-induced suppression of testosterone through nitric oxide production in male mice

Excessive nitric oxide (NO) production in mice serum and testis due to aluminum (Al) exposure has been shown in previous studies. The aim of this study was to further investigate the role of NO on aluminum-suppressed testosterone level in male CD-1 mice. Each animal in six groups, was given intraperitoneal injections of either saline, aluminum chloride (AlCl(3)), l-N(6)-(1-iminoethyl) lysine (NO synthase inhibitor, l-NIL), or Al chloride along with l-NIL for a period of 12 days. These groups were denoted as C (control, saline), AL (35mg Al/kg/day, saline), NIL240 (total 240mg l-NIL/kg, saline), ALNIL240 (35mg Al/kg/day, total 240mg l-NIL/kg), ALNIL60 (35mg Al/kg/day, total 60mg l-NIL/kg), and NIL60 (total 60mg l-NIL/kg, saline). Results indicated that serum/testicular aluminum levels increased significantly in aluminum-treated animals compared to the controls, whereas the values observed from groups ALNIL240 than AL/ALNIL60 were markedly lower. Aluminum administration significantly increased NO production and decreased both testicular adenosine 3',5'-cyclic monophosphate (cAMP) and testosterone levels. A lower level of NO and higher concentrations of cAMP and testosterone observed in the ALNIL240 group indicated that the protective effect of NO synthase blockage was significant, although incomplete. In addition, aluminum induction significantly elevated the testicular cholesterol, but the values were lower in the ALNIL240 group than the AL or the ALNIL60 group. Finally, it was suggested that aluminum compounds exerted a significant adverse effects on the steroidogenesis and cAMP, which aided in the transport of cholesterol to the inner mitochondrial membrane. Furthermore, nitric oxide synthase blockage prevented aluminum-induced reproductive toxicity.

Iron-mobilizing properties of the gadolinium-DTPA complex: clinical and experimental observations

BACKGROUND

Gadolinium (Gd) magnetic resonance imaging (MRI) contrast agents are considered to be safe in patients with impaired renal function. Our study investigates a mechanism of severe iron intoxication with life-threatening serum iron levels in a haemodialysis patient following MRI with Gd-diethylenetriaminepentaacetic acid (Gd-DTPA) administration. His previous history was remarkable for multiple blood transfusions and biochemical evidence of iron overload. We hypothesized that Gd-DTPA may have an iron-mobilizing effect in specific conditions of iron overload combined with prolonged exposure to the agent.

METHODS

For the in vitro study, Gd-DTPA was added to mice liver homogenate and iron metabolism parameters were measured after incubation in comparison with the same samples incubated with saline only. For the in vivo study, an experimental model of acute renal failure in iron-overloaded rats was designed. Previously iron-overloaded and normally fed rats underwent bilateral nephrectomy by renal pedicle ligation, followed by Gd-DTPA or saline injection. Iron and iron saturation levels were checked before and 24 h after Gd-DTPA or vehicle administration.

RESULTS

Significant mobilization of iron from mice liver tissue homogenate in mixtures with Gd in vitro was seen in the control (saline) and in the experimental (Gd) groups (513+/-99.1 vs 1117.8+/-360.8 microg/dl, respectively; P<0.05). Administration of Gd-DTPA to iron-overloaded rats after renal pedicle ligation caused marked elevation of serum iron from baseline 143+/-3.4 to 570+/-8 microg/dl (P<0.0001). There were no changes of the named parameter, either in iron-overloaded anuric rats after saline injection or in normal diet uraemic animals, following Gd-DTPA administration.

CONCLUSIONS

The combination of iron overload and lack of adequate clearance of Gd chelates may cause massive liberation of iron with dangerous elevation of free serum iron. It is highly recommended that after Gd contrast study, end-stage renal disease patients with probable iron overload should undergo prompt and intensive haemodialysis for prevention of this serious complication.

The effects of dialyzer reuse on plasma antioxidative mechanisms in patients on regular hemodialysis treatment

The effects of antioxidative mechanism are known to be reduced in patients on regular hemodialysis treatment (RHT). The data about the effects of reuse on antioxidative mechanisms are limited. Twelve patients on RHT (age range: 16-50 years) were included in the study. The basal and after 4 months of dialyzer reuse period, plasma antioxidant activity (AOA), myeloperoxidase (MPO) activity, ceruloplasmin (Cp), copper (Cu), transferrin (TF), and sulphydryl group (SH) levels were detected. The basal plasma AOA (110.92 +/- 17.19 microliters), TF (1.23 +/- 0.23 g/l), and SH (307.11 +/- 51.81 mumol/l) levels were lower than the levels of the control subjects (73.75 +/- 9.07 microliters, 2.38 +/- 0.25 g/l, 690.59 +/- 84.18 mumol/l) (p < .001). The basal Cp (0.47 +/- 0.08 g/l) and MPO activity (86.31 +/- 9.57 U/l) levels were higher than the levels of the control subjects (0.34 +/- 0.07 g/l and 65.90 +/- 7.28 U/l) (p < .001). The basal Cu levels (1.19 +/- 0.24 mg/l) were similar to the levels of the control subjects (1.11 +/- 0.13 mg/l) (p > .05). The difference between plasma AOA (83.33 +/- 14.71 microliters), Cp (0.38 +/- 0.08 g/l), and MPO activity (64.43 +/- 10.01 U/l) after the reuse period and the control values were not statistically significant (p > .05). The TF (1.87 +/- 0.15 g/l) levels after the reuse period were significantly lower than the control values (p < .001), although the levels were increased after the reuse period. Our findings may indicate some beneficial effects of hemodialyzer reuse process on plasma antioxidative mechanisms in patients on RHT.

Psychological effects of chronic haemodialysis

Ninety-four patients, partly on chronic haemodialysis, partly after successful kidney transplantation, were studied. Progress of perceptual performance was followed up by measurements of the reaction time. It is pointed out that accumulation of uraemic toxins causes permanent damage to the central nervous system. The psychological tests revealed behavioural and personality deviations typical of other chronic diseases, the main features being growing anxiety, neuroticitation, sense of inferiority, egocentric attitude, primitive defense reactions, social introversion, distorted image of the ego, etc. Dependence of the patients on the medical or nursing staff and on the dialysing system also favour these symptoms. The uncertain outcome of the illness and the "over-protective" attitude of the close or the more distant milieu also add to the sense of insecurity and uselessness. The need for individual and group psychotherapy is emphasized.

Serum and lymphocyte, aluminum and nickel in chronic renal failure

In the past decade, aluminum has been recognized as a toxic metal in patients with chronic renal failure. It is, however, possible that other trace metals, such as nickel, may also have toxic actions in these patients. The plasma concentration of a metal, such as aluminum or nickel, may not provide a valid index of either tissue content or total body burden. In the study reported here, the aluminum and nickel content of lymphocytes was measured and compared with plasma concentrations in normal controls and patients with chronic renal failure. The findings suggest that lymphocytes may be of value as a nucleated 'tissue' for the assessment of trace metal status.