Serum Trace Elements in Children with End-Stage Renal Disease

Role of Nutrients in Pediatric Non-Dialysis Chronic Kidney Disease: From Pathogenesis to Correct Supplementation

Nutrition management is fundamental for children with chronic kidney disease (CKD). Fluid balance and low-protein and low-sodium diets are the more stressed fields from a nutritional point of view. At the same time, the role of micronutrients is often underestimated. Starting from the causes that could lead to potential micronutrient deficiencies in these patients, this review considers all micronutrients that could be administered in CKD to improve the prognosis of this disease.

Nutrition for critically ill children and neonates requiring dialysis: Application of clinical practice recommendations

Approximately 30% of all children and neonates admitted to the intensive care unit (ICU) experience acute kidney injury (AKI). Children with AKI are largely poorly fed and experience high rates of malnutrition. Nutrition prescription and provision are exceptionally challenging for critically ill neonates, infants, and children with AKI given the dynamic nature of AKI and its respective treatment modalities. Managing the nutrition prescription of critically ill neonates, infants, and children with AKI requires nutrition support clinicians to have a high-level understanding of the various treatment modalities for AKI, which can affect the patient's protein, fluid, electrolyte, and mineral needs. Accurate and timely nutrition assessment in critically ill neonates and children with AKI can be flawed owing to difficulty obtaining accurate anthropometric parameters. Recently, the Pediatric Renal Nutrition Taskforce introduced clinical practice recommendations for the nutrition management of children with AKI. In this review, we will discuss the practical implications of these recent guidelines and work to bridge the knowledge and practice gaps for pediatric and neonatal nutrition support clinicians providing nutrition therapy for patients with AKI in the ICU. We also appraise special nutrition-related considerations for neonates with AKI given newer available renal replacement treatment modalities.

Serum Zinc Levels in Chronic Kidney Disease Patients, Hemodialysis Patients, and Healthy Controls: Systematic Review and Meta-Analysis

OBJECTIVES

Patients with chronic kidney disease (CKD) are susceptible to changes in zinc homeostasis through anorexia and dietary restrictions, as well as hemodialysis (HD). Changes in zinc homeostasis might predispose CKD and HD patients to specific adverse effects, including erythropoietin-resistant anemia, oxidative stress, atherosclerosis, and cardiovascular disease. Because serum zinc levels are rarely measured in CKD and HD patients, zinc supplementations do not represent a routine therapy for CKD and dialysis patients. Therefore, in this meta-analysis, we aimed to assess serum zinc levels in CKD and HD patients compared with healthy controls (HC). In addition, we investigated whether HD affects serum zinc levels by comparing serum zinc levels in HD versus CKD patients and comparing serum zinc pre- versus post-HD.

DESIGN AND METHODS

A comprehensive search of databases was conducted to identify either observational studies or randomized trials that assessed serum zinc levels in either CKD and/or HD patients in comparison to HC. We conducted a random-effects meta-analysis.

RESULTS

Our meta-analysis included 42 studies with a total of 4,161 participants, of whom 460 were CKD patients, 2,047 were HD patients, and 1,654 were HCs. Both CKD and HD patients showed lower serum zinc levels compared with HC (mean difference = -22.86 μg/dL, 95% CI -33.25 to -12.46; mean difference = -13.64 μg/dL, 95% CI -21.47 to -53.80, respectively). CKD and HD patients showed no significant difference in serum zinc levels (mean difference = 15.39, 95% CI -8.91 to 39.68). Pre-HD serum zinc levels were significantly lower than those post-HD (mean difference = -7.51 μg/dL, 95% CI -14.24 to -0.78).

CONCLUSION

In the current study, the serum zinc levels were lower in CKD and HD patients compared to HCs and appears to be more common than reported in daily clinical practice. It may be beneficial to assess serum zinc levels in CKD and HD patients. More research on zinc in kidney disease is encouraged.

Beneficial effects of procyanidin B2 on adriamycin-induced nephrotic syndrome mice: the multi-action mechanism for ameliorating glomerular permselectivity injury

Despite considerable advances in prevention, diagnosis, and therapy, nephrotic syndrome (NS) remains a significant cause of high morbidity and mortality globally. As a result, there is an urgent need to identify novel effective preventative and therapeutic agents for NS. NS is implicated in glomerular permselectivity injury, which can be attributed to oxidative distress, inflammation, lipid nephrotoxicity, podocyte apoptosis, autophagy dysfunction, and slit diaphragm (SLD) dysfunction. In addition to its well-documented antioxidant potency, procyanidin B2 (PB2) may exhibit pleiotropic effects by targeting various canonical signaling events, such as NF-κB, PPARs, PI3K/Akt, mTOR, and the caspase family. As a result, PB2 may be a promising therapeutic target against NS. To test this hypothesis, we established an Adriamycin (ADR)-induced NS mouse model to evaluate the pleiotropic renoprotective effects of PB2 on NS. Here, we demonstrated that PB2 improves podocyte injury via inhibition of NOX4/ROS and Hsp90/NF-κB to exhibit antioxidant and anti-inflammatory potency, respectively. We also show that PB2 indirectly activates the PI3K/Akt axis by regulating SLD protein levels, resulting in normalized podocyte apoptosis and autophagy function. Further, loss of albumin (ALB) induces lipid nephrotoxicity, which we found to be alleviated by PB2 via activation of PPARα/β-mediated lipid homeostasis and the cholesterol efflux axis. Interestingly, our results also suggested that PB2 reduces electrolyte abnormalities and edema. In addition, PB2 may contribute protective effects against trace element dys-homeostasis, which, through alleviating serum ALB loss, leads to a protective effect on glomerular permselectivity injury. Taken together, our results reveal that the identified mechanisms of PB2 on NS are multifactorial and involve inhibition of oxidative distress and inflammatory responses, as well as improvements in podocyte apoptosis and autophagy dysfunction, amelioration of lipid nephrotoxicity, and modulation of electrolyte abnormalities and edema. Thus, we provide a theoretical basis for the clinical application of PB2 against NS.

Circulatory Imbalance of Essential and Toxic Trace Elements in Pre-dialysis and Hemodialysis Patients

The status of essential and toxic trace elements in patients with different stages of chronic kidney disease (CKD) is still unclear and not well characterized. The present study examined the circulatory levels of a wide panel of trace elements (Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cd, Pb, and U) in hemodialysis patients (HD group) and pre-dialysis patients with stage 3 CKD (PD group). Comparisons were made between groups of patients and healthy individuals from the control group (CG). The levels of Al, Mn, Co, Ni, Cu, As, Se, Sr, and Pb were higher, while the levels of Cr, Zn, Rb, Cd, and U were lower in HD patients than in our CG. Higher levels of Al and Se, as well as lower levels of As, Sr, Zn, Rb, and U were significant and distinguished HD from PD. Among other analyzed elements, Co, Se, and U are the only trace elements that did not distinguish PD from CG at a statistically significant level. The HD group had lower serum U levels than the PD group, and this could be a result of hemodialysis. This study also revealed that the Cu/Zn ratio could be used as a marker for early and late detection of renal failure. Marked changes of essential and toxic trace element levels in sera indicate additional pathophysiological events in CKD, which could additionally contribute to the preexisting increased morbidity of HD patients. Measurement of trace elements in HD patients should be performed routinely.

The Role of Zinc in Cardiovascular Disease

Zinc is an essential trace element due to its role as a key part of human enzymatic activity. As a cofactor in metalloenzymes and metalloproteins, zinc participates in diverse biological functions, including gene transcription, translation, and replication, phagocytosis, and immunoglobulin and cytokine production. In this review, we will focus on the role of zinc in the cardiovascular system, including heart failure, vascular calcification, and myocardial infarction. We will further highlight the role of zinc in cardiovascular pathology in individuals with chronic kidney disease, and type II diabetes mellitus, groups uniquely at risk for cardiovascular morbidity and mortality.

Differences in Dietary Intake and Vitamin and Mineral Status of Infants and Children on Dialysis Receiving Feeds or Eating Normal Food

OBJECTIVES

Knowledge of the vitamin and mineral intake and status of children on dialysis is scarce. Guidelines suggest supplementation of water-soluble vitamins, but the need for supplementation of minerals is less clear. We evaluated vitamin and mineral intake and status of children on chronic dialysis in our center.

METHODS

We reviewed patient records of all 33 children aged 0-16 years who were treated with chronic dialysis at a University Hospital between December 2014 and August 2019. Dietary intake was estimated from feed prescriptions and 3-day food records. Vitamin and mineral determinations were performed as part of routine care.

RESULTS

Food records or adherence to dietary prescription of feeds were available for 29 children. Dietary intake of most nutrients was sufficient in children on feeds, but children not on feeds had low intakes of vitamins D, B1, B2, and B6 as well as zinc, iron, and calcium from their diet. Insufficient intake was corrected with supplementation. We discovered some children with blood concentrations below the reference range for vitamins D (3.1%) and C (15.4%) and copper (16.7%) and selenium (3.1%). In contrast, various proportions of children with blood concentrations above the reference range were detected for all nutrients apart from vitamin D.

CONCLUSIONS

In our study, children receiving sufficient amounts of renal-specific feeds to meet at least 100% of age-specific requirements do not appear to need multivitamin-mineral supplementation, apart from vitamin D and calcium; in addition, children on PD usually need a sodium supplement and, on rare occasions with low intake from feeds, a phosphate supplement is needed. This study further revealed that other children at our center are more prone to deficient intakes of several vitamins and minerals, requiring supplementation based on dietetic review and, in some instances, laboratory measurements.

Vitamin and trace element concentrations in infants and children with chronic kidney disease

BACKGROUND

There are limited data regarding vitamin and trace element blood concentrations and supplementation needs in children with non-dialysis stages 3-5 of chronic kidney disease (CKD).

METHODS

Retrospective cross-sectional review for nutritional blood concentrations measured over a recent 2-year period. In our CKD clinics, nutritional bloods including copper, zinc, selenium and vitamin A, vitamin E, active vitamin B12 and folate are monitored annually. Vitamin D status is monitored every 6-12 months.

RESULTS

We reviewed 112 children (70 boys) with median (IQ1, IQ3) age 8.97 (4.24, 13.80) years. Estimated median (IQ1, IQ3) GFR (mL/min/1.73 m2) was 28 (21, 37). Vitamin A, active vitamin B12 and vitamin E concentrations were within normal range in 19%, 23% and 67% respectively, with all others being above normal range. Vitamin D blood concentrations were within desired range for 85% (15% had low levels) and folate blood concentrations were within normal range in 92%, with the remainder above or below target. For trace elements, 60%, 85% and 87% achieved normal ranges for zinc, selenium and copper respectively. Deficiencies were seen for zinc (35%), copper (7%), folate (3%) and selenium (1%), whilst 5%, 6% and 14% had zinc, copper and selenium levels above normal ranges.

CONCLUSIONS

Several vitamin and trace element blood concentrations were outside normal reference ranges. Monitoring vitamin D and zinc blood concentrations is indicated due to the percentages with low levels in this group. Targeted vitamin and trace element supplementation should be considered where indicated rather than commencing multivitamin and/or mineral supplementation. Graphical abstract Vitamin and trace element concentrations in infants and children with non-dialysis chronic kidney disease.

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.

Effects of Zinc Supplementation on Nutritional Status in Children with Chronic Kidney Disease: A Randomized Trial

BACKGROUND

Zinc is an essential micronutrient for human beings and its deficiency affects their normal growth and development.

OBJECTIVE

The main aim was to evaluate the effect of two doses of zinc supplementation (ZS) on the nutritional status in chronic kidney disease (CKD) children.

METHODS

A randomized-trial multicentric study was conducted in 48 CKD (23 females) patients under 18-years-old, for a year. At random, participants took 30 or 15 mg/day of ZS, respectively. Anthropometric measurements and biochemical analysis were performed. Hypozincemia was determined by serum zinc concentration (SZC) using atomic absorption spectrophotometry. The positive or negative change in patients' body mass index (BMI) Z-score, serum albumin, zinc and C-reactive protein (CRP) levels were used to evaluate the effect of ZS.

RESULTS

Mean SZC was normal before and after ZS. Despite ZS, there were no significant changes in serum albumin, zinc and CRP levels. A positive and significant association was observed between SZC and serum albumin before (p = 0.000) and after (p = 0.007) ZS. In both groups of ZS, there was a small but positive and significant change in body mass and normalization in BMI Z-score, hypoalbuminemia, hypozincemia and high CRP, especially with 30 mg/day of ZS.

CONCLUSIONS

Zinc supplementation may be beneficial for nutritional status in children and adolescents with CKD.