Effect of selenium supplementation on hemodialysis patients: a meta-analysis

PURPOSE

Hemodialysis (HD) patients commonly experience enhanced oxidative stress and inflammation, potentially increasing the risk of malnutrition. Selenium levels are typically lower in HD individuals. Selenium deficiency has been identified as a risk factor for oxidative stress and inflammatory responses. Therefore, we intended to perform a meta-analysis to assess the impact of selenium supplementation on HD patients.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were searched for randomized controlled trials (RCTs) on the effect of selenium supplementation on HD patients until September 31, 2024. The data analysis was conducted using Stata15.0 software.

RESULTS

Seven RCTs, with 2080 participants, were finally included, with 1029 in the selenium group and 1051 in the control group. The meta-analysis unraveled no statistically significant impact of selenium supplementation on body mass index (SMD = 0.15, 95% CI (- 0.20, 0.49), triglyceride [(SMD = - 0.02, 95% CI (- 0.44, 0.41)], total cholesterol [(SMD = - 0.18, 95%CI (- 0.41, 0.05)], low-density lipoprotein [(SMD = - 0.37, 95% CI (- 1.04, 0.31)], high-density lipoprotein cholesterol [(SMD = 0.15, 95% CI (- 0.54, 0.84)], C-reactive protein [(SMD = - 0.10, 95% CI (- 0.46, 0.27)], ferritin [(SMD = - 0.02, 95% CI (- 0.29, 0.26)], Hx-C reactive protein [(SMD = 0.00, 95% CI (- 1.02, 1.03)], and hemoglobin [(SMD = 0.01, 95% CI (- 0.57,0.59)]. Only selenium levels were significantly increased after selenium supplementation [SMD = 2.83, 95% CI (2.43, 3.24)].

CONCLUSION

Selenium supplementation can increase selenium levels in HD patients, without notable impacts on weight, triglycerides, and total cholesterol.

The effects of selenium supplementation on lipid profile in adults: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Dyslipidemia with a considerable progression rate is a primary risk factor for CVDs if left untreated. Dietary interventions have explored the health influences of selenium on lipid profiles in adults, yet the findings remain contentious. This study seeks to determine if selenium supplementation can positively modify the lipid profile (total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL), and high-density lipoprotein cholesterol (HDL-C) in adults.

METHODS

Using predefined keywords, we searched online databases, including Scopus, PubMed, Web of Science Core Collection, and Google Scholar, for relevant studies published from inception through July 2024. A random-effects meta-analysis was then employed to pool the weighted mean differences (WMD) and 95 % CI for outcomes assessed by a minimum of three studies.

RESULTS

Initially 1205 studies were obtained out of which 25 RCTs were decided to be included for further analyses. Selenium supplementation reduced VLDL (WMD: -1.53; 95 % CI: -2.86, -0.20), but did not change TG (WMD: 1.12; 95 % CI: -4.51, 6.74), TC (WMD: -2.25; 95 % CI: -6.80, 2.29), LDL-C (WMD: 1.60; 95 % CI: -4.26, 7.46), and HDL-C levels (WMD: 0.98; 95 % CI: - 0.02, 1.98).

CONCLUSION

Our study showed significantly reduced VLDL but limited effects were observed in other lipid indexes. More extensive RCTs are required globally to achieve a holistic comprehension of the connection between selenium and lipid profile.

Selenium, a Notable Micronutrient: A Crucial Element in the Context of All-Cause Long-Term Mortality in Renal Failure

Selenium is a trace element involved in crucial antioxidative and anti-inflammatory processes in the body. Low selenium status has been linked to increased mortality due to compromised immune function and heightened risk of cardiovascular events. Patients with chronic kidney disease (CKD) face elevated mortality risks, prompting the need for strategies to mitigate these events. Selenium deficiency is prevalent among CKD patients, yet the long-term implications and its association with mortality in this population remain unclear. This study assessed seventy-five CKD patients' serum selenium levels (SSL) between January and February 2020. The objective was to investigate the correlation between SSL and 36-month all-cause mortality in CKD patients. Baseline laboratory values, dialysis adequacy, Charlson comorbidity index (CCI), serum selenium status, and all-cause mortality at 36 months were subjected to statistical analysis. Significance level was set at p < 0.05. Significant differences were observed in CCI between surviving and deceased groups, with deceased patients being older and afflicted with more comorbidities. SSL also exhibited a significant difference between the groups, with levels in the mortality group significantly lower than those in other patients, suggesting a potential role of selenium in predicting patient outcomes. SSL equal to or lower than 66.35 were associated with approximately 5 times higher likelihood of mortality within three years of follow-up. Our study highlights the significant association between low serum selenium levels and survival in patients with chronic kidney disease, underscoring the potential importance of selenium monitoring in this population. These findings emphasize the need for further research to elucidate the underlying mechanisms and to explore potential interventions aimed at improving outcomes in CKD patients.

Selenium supplementation in chronic kidney disease patients undergoing haemodialysis: a systematic review of the effects on plasma selenium, antioxidant and inflammatory markers, immunological parameters and thyroid hormones

Selenium (Se) is a mineral with several biological functions, and studies have shown that its deficiency can be linked to many complications in patients with chronic kidney disease (CKD). This study aims to systematically review the effects of Se supplementation in patients with CKD undergoing haemodialysis (HD). This systematic review was carried out according to the PRISMA statement. Clinical trials were searched in PubMed, Lilacs, Embase, Scopus and Cochrane Library databases from inception to July 2021 and updated in July 2024. The protocol was registered on PROSPERO (CRD42021231444). Two independent reviewers performed the study screening and data extraction, and the risk of bias was evaluated using the Cochrane Collaboration tool. Thirteen studies were included in this review. Only nine studies showed results on Se levels; in all, reduced Se levels were observed before supplementation. A positive effect of supplementation on plasma Se level was demonstrated. Of the ten studies analysed, six demonstrated positive effects on antioxidant and inflammatory markers. Only one study analysed immunological parameters, showing a positive impact. From two studies that analysed thyroid hormones, only one showed positive results. All studies were classified as high risk of bias. The findings suggest that Se supplementation significantly increases plasma Se levels in these patients; however, there are still not enough studies to clarify the effects of Se supplementation on the antioxidant and inflammatory markers, immune system and thyroid hormones. Further studies are needed to elucidate the effects of Se supplementation and to provide a recommendation for patients with CKD undergoing HD.

Therapeutic Effect of Natural Products and Dietary Supplements on Aflatoxin-Induced Nephropathy

Aflatoxins are harmful natural contaminants found in foods and are known to be hepatotoxic. However, recent studies have linked chronic consumption of aflatoxins to nephrotoxicity in both animals and humans. Here, we conducted a systematic review of active compounds, crude extracts, herbal formulations, and probiotics against aflatoxin-induced renal dysfunction, highlighting their mechanisms of action in both in vitro and in vivo studies. The natural products and dietary supplements discussed in this study alleviated aflatoxin-induced renal oxidative stress, inflammation, tissue damage, and markers of renal function, mostly in animal models. Therefore, the information provided in this review may improve the management of kidney disease associated with aflatoxin exposure and potentially aid in animal feed supplementation. However, future research is warranted to translate the outcomes of this study into clinical use in kidney patients.

Fortified synbiotic dessert for improving malnutrition in hemodialysis patients: A randomized, double-blind, controlled trial

As dysbiosis of gut microbiota is recognized as a major risk factor for malnutrition in hemodialysis (HD) patients, we aimed to assess the effects of fortified synbiotic dessert on malnutrition, oxidative stress, inflammation, and quality of life in patients undergoing hemodialysis. A total of 50 hemodialysis patients were randomized into two groups of intervention and control to consume either 50 g of synbiotic dessert fortified with vitamin D (1000 IU) and calcium (500 mg) (FSD) or 50 g of control dessert (CD) for 8 weeks, respectively. Changes in nutritional status [Subjective Global Assessment (SGA)], anthropometric measures, malondialdehyde (MDA), total antioxidant capacity (TAC), high-sensitivity C-reactive protein (hs-CRP), ferritin, biochemistry [serum albumin, vitamin D, creatinine, blood urea nitrogen (BUN), complete blood count (CBC), and electrolytes], and quality of life were assessed before and at the end of the trial. The SGA scores and serum ferritin levels decreased significantly in the FSD group compared to the control group (p = .01 and p = .03, respectively). Regarding other markers, no statistically significant changes were found comparing the two groups. This novel fortified synbiotic dessert as a functional food may be effective in reducing the severity of malnutrition by improving SGA score in short term in hemodialysis patients. Thus, it is suggested to do further studies to elucidate the possible mechanisms related to the effects of this dessert on microbiota, skeletal muscle mass, and inflammation in HD in long term.

Progress in the study of nutritional status and selenium in dialysis patients

Malnutrition is very common in patients with chronic kidney disease, especially in those on maintenance dialysis. Malnutrition is one of the major factors affecting survival and death of dialysis patients, and reducing their activity tolerance and immunity. There are numerous and interacting risk factors for malnutrition, such as reduced nutritional intake, increased energy expenditure, hormonal disorders, and inflammation. Selenium, in the form of selenoproteins, is involved in many physiological processes in the body and plays an important role in maintaining redox homeostasis. Oxidative stress and infection are very common in dialysis patients, and selenium levels in dialysis patients are significantly lower than those in the healthy population. It has been shown that there is a correlation between selenium levels in hemodialysis patients and their nutrition-related indicators, and that selenium supplementation may improve malnutrition in patients. However, further studies are needed to support this conclusion and there is a lack of basic research to further characterize the potential mechanisms by which selenium may improve malnutrition in dialysis patients. The purpose of this review is to provide a comprehensive overview of factors associated with malnutrition in dialysis patients and to describe the progress of research on nutritional status and selenium levels in dialysis patients.

A systematic review and dose-response meta-analysis of the effect of selenium supplementation on serum concentration of C-reactive protein

BACKGROUND

Despite conducting new studies on the potential effect of selenium in reducing inflammation; results held contradictory weights and turns into an intriguing area of research. Concerns have been raised on this matter on hand to reach conclusive/consistent results. Therefore, this study seeks to address this scientific gap by assessing randomized controlled trials (RCTs) investigating the effect of selenium intake on C-reactive protein (CRP).

METHOD AND MATERIALS

To find all the relevant English-language RCTs, databases including SCOPUS, Web of Science, Clinical Trials.gov, PubMed, and Cochrane Library were searched with no time limit (up to June 2022). Based on the mean changes for both comparison and intervention groups, the effect sizes were calculated. Further, DerSimonian and Laird random-effects model was performed to determine the summary of overall effects and their heterogeneity.

RESULTS

Fifteen studies were selected for systematic review and thirteen studies were known to be eligible for meta-analysis. Meta-analysis results indicated a significant effect in serum CRP concentrations compared to the control group (weighted mean difference (WMD)= -0.22 mg/L 95 % confidence interval (CI): - 0.39, - 0.04; p = 0.014).

CONCLUSION

In conclusion, our study confirms the downward effect of selenium on the serum concentration of CRP. On a wider level, further research is also needed to assess the selenium effect on other inflammatory mediators.

Blood Selenium Concentrations Are Inversely Associated with the Risk of Undernutrition in Older Adults

BACKGROUND

Selenium is an essential trace element with an antioxidant and anti-inflammatory capacity that has been associated in experimental studies with beneficial effects on appetite control, the regulation of the gut microbiota, and control of the anabolic-catabolic balance. The main aim of the present study was to evaluate the association between circulating selenium concentrations and the risk of developing undernutrition in older adults.

METHODS

This was a cohort study with 1398 well-nourished community-dwelling individuals aged ≥ 65 years residing in Spain in 2017, who were followed for a mean of 2.3 years. Whole blood selenium was measured at baseline using inductively coupled plasma-mass spectrometry. Undernutrition was assessed at baseline and at follow-up, and defined as having at least one of the three GLIM phenotypic criteria (involuntary weight loss, a low body mass index, and a reduced muscle mass) and at least one of the two etiologic criteria (reduced food consumption or nutrient assimilation and inflammation/disease burden).

RESULTS

During the follow-up, 142 participants (11%) developed moderate undernutrition and 113 (8.8%) severe undernutrition. The standardized relative risks of moderate and severe undernutrition at the 75th percentile of Se levels versus the 25th were 0.90 and 0.70, respectively. In dose-response analyses, the risk of severe undernutrition decreased linearly with increasing selenium concentrations. This association was independent of protein intake or diet quality and was stronger among participants with a diagnosis of a musculoskeletal disorder.

CONCLUSIONS

The results suggest that an adequate dietary selenium status is needed to prevent undernutrition in older adults. Also, this may open the door for clinical trials with selenium supplementation, at doses considered as safe, to prevent undernutrition.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

Low selenium intake is associated with risk of all-cause mortality in kidney transplant recipients

BACKGROUND

Deficiency of the essential trace element selenium is common in kidney transplant recipients (KTR), potentially hampering antioxidant and anti-inflammatory defence. Whether this impacts the long-term outcomes of KTR remains unknown. We investigated the association of urinary selenium excretion, a biomarker of selenium intake, with all-cause mortality; and its dietary determinants.

METHODS

In this cohort study, outpatient KTR with a functioning graft for longer than 1 year were recruited (2008-11). Baseline 24-h urinary selenium excretion was measured by mass spectrometry. Diet was assessed by a 177-item food frequency questionnaire, and protein intake was calculated by the Maroni equation. Multivariable linear and Cox regression analyses were performed.

RESULTS

In 693 KTR (43% men, 52 ± 12 years), baseline urinary selenium excretion was 18.8 (interquartile range 15.1-23.4) μg/24-h. During a median follow-up of 8 years, 229 (33%) KTR died. KTR in the first tertile of urinary selenium excretion, compared with those in the third, had over a 2-fold risk of all-cause mortality [hazard ratio 2.36 (95% confidence interval 1.70-3.28); P < .001], independent of multiple potential confounders including time since transplantation and plasma albumin concentration. The most important dietary determinant of urinary selenium excretion was protein intake (Standardized β 0.49, P < .001).

CONCLUSIONS

Relatively low selenium intake is associated with a higher risk of all-cause mortality in KTR. Dietary protein intake is its most important determinant. Further research is required to evaluate the potential benefit of accounting for selenium intake in the care of KTR, particularly among those with low protein intake.

Selenium supplementation decreases CRP and IL-6 and increases TNF-alpha: A systematic review and meta-analysis of randomized controlled trials

Inflammation is an initiating cause of infectious and non-infectious diseases. Studies have shown that selenium (Se) has anti-inflammatory effects. However, its' effects on serum c-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) plasma concentrations are equivocal. Therefore, we performed a systematic review and meta-analysis of randomized controlled trials (RCTs), evaluating the effects of per oral (PO) and intravenous (IV) Se supplementation on CRP, TNF-α, and IL-6. A systematic search was conducted using four databases, including PubMed, Google Scholar, Cochrane Library, and Scopus to find randomized clinical trials, published up to April 2023. From 19476 papers, after screening and removing duplicate articles, 24 studies were analyzed in the present meta-analysis. In the pooled analysis, PO Se administration showed no significant effect on CRP (WMD: 0.12; 95 % CI -0.11, 0.38; P-value= 0.30). However, IV Se supplementation had a significant negative association with CRP concentration (-2.24; 95 % CI: -4.24, -0.24; p-value: 0.02). Se administration had no significant association with TNF-α plasma concentration (9.64, 95 % CI: -0.59, 19.88, p-value= 0.06; and heterogeneity: 98 %). However, a significant positive association was present between Se and plasma TNF-α concentrations (0.15, 95 % CI: 0.14, 0.17, P-value<0.0001). Moreover, Se supplementation had a significant negative correlation with IL-6 plasma concentration in PO (-0.54; 95 % CI: -1.61, 0.52; P-value = 0.31) and IV administrations (-4.77; 95 % CI: -7.61, -1.93; P-value<0.0001), respectively. This study demonstrated that IV Se administration reduced CRP and IL-6 plasma concentrations. Conversely, IV Se supplementation increased TNF-α plasma concentration. It is evident that further, well-controlled clinical trials are required.

Do trace elements play a role in coronary artery calcification in hemodialysis patients?

PURPOSE

Abnormalities of trace elements have previously been linked to inflammatory processes in hemodialysis (HD) patients. We aimed to establish the trace element status of maintenance HD patients, to investigate the relationship between coronary artery calcification scores (CACs) and whole blood levels of trace elements.

METHODS

Patients undergoing HD in three times a week for > 6 months and age-and sex-matched controls were included from October 2015 to June 2016. Data were collected from patient files. All subjects' whole blood levels of trace elements were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). CACs for patients were assessed by multi-detector computed tomography.

RESULTS

The 35 patients (male, 60%) with a mean age of 45.7 ± 10.4 years and 35 controls were included. HD patients showed significantly lower levels of selenium and uranium and higher cadmium (Cd), cobalt, lithium, manganese, nickel, lead, platinum, tin, strontium, and thallium levels compared to controls. Coronary artery calcification (CAC) was present in 21 patients (60%), and median CACs were 14.2 (IQR 0-149). Patients with CACs > median were significantly older, had a higher prevalence of hypertension and lower ALP levels than patients with CACs ≤ median. No significant differences in whole blood levels of trace elements were found between patients with CACs > median and patients with CACs ≤ median. A near significance was noted in median whole blood levels of Cd between these groups (P = 0.096). According to multivariate analysis, age was the only independent determinant for CAC development.

CONCLUSION

Age is independently associated with coronary vascular calcification. High Cd levels might play a role in CAC development in HD patients.

Genetically predicted body selenium concentration and eGFR: A Mendelian randomization study

Introduction

Selenium is a trace mineral that is commonly included in micronutrient supplements. The effect of selenium on kidney function remains unclear. A genetically predicted micronutrient and its association with estimated glomerular filtration rate (eGFR) can be used to assess the causal estimates by Mendelian randomization (MR).

Methods

In this MR study, we instrumented 11 genetic variants associated with blood or total selenium levels from a previous genome-wide association study (GWAS). The association between genetically predicted selenium concentration and eGFR was first assessed by summary-level MR in the chronic kidney disease(CKDGen) GWAS meta-analysis summary statistics, including 567,460 European samples. Inverse-variance weighted and pleiotropy-robust MR analyses were performed, in addition to multivariable MR adjusted for the effects of type 2 diabetes mellitus. Replication analysis was performed with individual-level UK Biobank data, including 337,318 White individuals of British ancestry.

Results

Summary-level MR analysis indicated that a genetically predicted 1 SD increase in selenium concentration was significantly associated with lower eGFR (-1.05 [-1.28, -0.82] %). The results were similarly reproduced by pleiotropy-robust MR analysis, including MR-Egger and weighted-median methods, and consistent even in the multivariable MR adjusted for diabetes. In the UK Biobank data, genetically predicted higher selenium concentration was also significantly associated with lower eGFR (- 0.36 [-0.52, -0.20] %), and the results were similar when body mass index, waist circumference, hypertension, and diabetes mellitus covariates were adjusted (-0.33 [-0.50, -0.17] %).

Conclusion

This MR study supports the hypothesis that higher genetically predicted body selenium is causally associated with lower eGFR.

The effects of selenium supplementation on inflammatory markers in critically ill patients

Abstract

Low serum selenium (Se) levels have been shown in critical illness, which is associated with poor clinical outcomes and a higher mortality rate. Se plays an important role in inflammation and oxidative stress. Since the overproduction of inflammatory cytokines and increased oxidative stress is a major component of critical illnesses, its supplementation has been demonstrated to have promising effects on critically ill patients. This study aims to review the evidence regarding the effects of Se supplementation on inflammatory and oxidative markers in critically ill patients. The literature review highlights alterations of inflammatory markers, including procalcitonin, leukocyte count, albumin, prealbumin, C-reactive protein (CRP), inflammatory cytokines, and cholesterol following Se supplementation in critically ill patients. Besides, the antioxidant properties of Se due to its presence in the structure of several selenoenzymes have been reported.

Article highlights

Low serum Se level have been shown in critical illness, which is associated with poor clinical outcome and higher mortality rate.

Se plays an important role in inflammation and oxidative stress.

Se supplementation can have promising effects by alterations of inflammatory markers and its antioxidant properties for critically ill patients.

The Role of Nutrition on Meta-inflammation: Insights and Potential Targets in Communicable and Chronic Disease Management

PURPOSE OF REVIEW

Chronic low-grade inflammation may contribute to the onset and progression of communicable and chronic diseases. This review examined the effects and eventual mediation roles of different nutritional factors on inflammation.

RECENT FINDINGS

Potential nutritional compounds influencing inflammation processes include macro and micronutrients, bioactive molecules (polyphenols), specific food components, and culinary ingredients as well as standardized dietary patterns, eating habits, and chrononutrition features. Therefore, research in this field is still required, taking into account critical aspects of heterogeneity including type of population, minimum and maximum intakes and adverse effects, cooking methods, physiopathological status, and times of intervention. Moreover, the integrative analysis of traditional variables (age, sex, metabolic profile, clinical history, body phenotype, habitual dietary intake, physical activity levels, and lifestyle) together with individualized issues (genetic background, epigenetic signatures, microbiota composition, gene expression profiles, and metabolomic fingerprints) may contribute to the knowledge and prescription of more personalized treatments aimed to improving the precision medical management of inflammation as well as the design of anti-inflammatory diets in chronic and communicable diseases.

The effects of selenium supplementation on blood lipids and blood pressure in adults: A systematic review and dose-response meta-analysis of randomized control trials

BACKGROUND

Previous studies evaluating the effects of selenium supplementation on lipid profile and blood pressure (BP) offer contradictory findings. This systematic review and meta-analysis assessed the effects of selenium supplementation on these lipid profile and BP.

METHODS

In order to identify interrelated clinical trials, we performed a comprehensive literature search in the online databases, including PubMed, Scopus, Embase, and ISI web of science, up to December 2021.

RESULTS

The analysis of the data established that selenium supplementation did not significantly affect TG level (WMD: -0.84 mg/dL; 95 % CI: -4.74, 3.05, p = 0.671), LDL-C (WMD: 0.86 mg/dL; 95 % CI: -1.21, 2.95, p = 0.416), and HDL-C (WMD: 0.3 mg/dL; 95 % CI: -0.66, 1.27, p = 0.535). however, there was a significant reduction in TC levels following selenium supplementation (WMD: -2.11 mg/dL; 95 % CI: -4.09, -0.13, p = 0.037). After subgroup analysis, when the baseline levels of LDL-C were < 130 mg/dL, selenium supplementation elicited a significant increase in LDL-C levels (WMD: 2.89 mg/dL; 95 % CI: 0.26, 5.51, p = 0.031). For BP, selenium supplementation significantly increased SBP (WMD: 2.02 mmHg; 95 % CI: 0.50, 3.55, p = 0.009), while it had no significant effect on DBP (WMD: 0.39 mmHg; 95 % CI: (-0.89, 1.68, p = 0.551)).

CONCLUSION

Although our findings suggest selenium may have possible therapeutic effects in improving TC and VLDL, because of its negative effects on LDL and BP, selenium supplementation for cardiovascular protection should be recommended with caution.

Long-Term Selenium-Yeast Supplementation Does Not Affect Bone Turnover Markers: A Randomized Placebo-Controlled Trial

Higher selenium status has been associated with lower bone turnover markers (BTM) in epidemiological studies. However, the long-term impact of selenium supplementation on BTMs has not been studied. We investigated the effects of selenium supplementation on BTMs including osteocalcin (OC), procollagen type I N-terminal propeptide (PINP), collagen type I cross-linked C-telopeptide (CTX), and bone alkaline phosphatase (BALP) in the short (6 months) and long term (5 years). A total of 481 Danish men and women (60-74 years) were randomized to receive placebo-yeast versus 100, 200, or 300 μg selenium as selenium-enriched yeast daily for 5 years. Plasma selenium concentration was measured using inductively coupled plasma mass spectrometry, and BTMs were measured in nonfasted samples at baseline, 6 months, and 5 years. Data were analyzed by ANCOVA to investigate the shape of the dose-response relationships. Covariates included age, body mass index, baseline selenium status, baseline BTM, smoking, alcohol, supplement use, and medication. Plasma selenium concentration (mean 86.5 μg/d at baseline) increased significantly with increasing selenium supplementation to 152.6, 209.1, and 253.7 μg/L after 6 months and remained elevated at 5 years (158.4, 222.4, and 275.9 μg/L for 100, 200, and 300 μg supplemental selenium/d, respectively (p < 0.001)). There was no change in plasma selenium concentration in the placebo-treated group. There was no significant effect of selenium supplementation on OC (6 months p = 0.37; 5 years p = 0.63), PINP (6 months p = 0.37; 5 years p = 0.79), CTX (6 months p = 0.91; 5 years p = 0.58) or BALP (6 months p = 0.17; 5 years p = 0.53). The relatively replete baseline selenium status in the study participants may explain this lack of effect. Testing in more deficient populations may provide further insights into the impact of selenium supplementation on bone health. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Micronutrients and Renal Outcomes: A Prospective Cohort Study

Background: Micronutrients are essential in maintaining normal human physiology. Data regarding the association between micronutrients and renal outcomes in chronic kidney disease (CKD) are lacking. Methods: This prospective observational cohort study enrolled 261 patients with CKD stages 1−5 and 30 subjects with normal renal function. Baseline serum zinc (Zn), selenium (Se), chromium, manganese, and copper, and laboratory tests were performed at enrolment. The primary endpoint was the presence of end-stage renal disease (ESRD) requiring long-term renal replacement therapy. Results: The median follow-up periods of renal and non-renal survivals were 67.78 and 29.03 months, respectively. Multiple linear regression showed that Zn and Se (β ± SE: 24.298 ± 8.616, p = 0.005; 60.316 ± 21.875, p = 0.006, respectively) levels were positively correlated with renal function. Time to ESRD was significantly longer for those with Zn levels ≥1287.24 ng/g and Se levels ≥189.28 ng/g (both p < 0.001). Cox regression analysis identified a higher Zn level as an independently negative predictor of ESRD after adjusting for renal function (hazard ratio, 0.450, p = 0.019). Conclusion: Serum Se and Zn concentrations are positively associated with renal function and better renal outcomes. A higher Zn concentration could independently predict better renal survival.

Selenium Deficiency Induces Apoptosis and Necroptosis Through ROS/MAPK Signal in Human Uterine Smooth Muscle Cells

Selenium (Se) is one of the essential trace elements; its deficiency induces ROS production and cell death in cardiomyocytes, skeletal muscle cells, and vascular smooth muscle cells, but it is still not clear the impact of Se deficiency on human uterine smooth muscle cells (HUSMCs). To investigate the effect of low Se on the mRNA expression of selenoproteins, the mRNA and protein expression of apoptosis and necroptosis of HUSMCs and their mechanism, Se deficient HUSMCs mode was established through culturing with 1% FBS containing 0 ng/mL, 0.7 ng/mL, and 7 ng/mL Se, and 10% FBS was as the control group. Then, the apoptosis and necroptosis rates, intracellular ROS content and the expression levels of selenoproteins, apoptosis, necroptosis, MAPK pathway-related genes were examined under different Se concentrations. The results showed that Se deficiency led to the augment of cell apoptosis and necroptosis in HUSMCs (p < 0.05), downregulated (p < 0.05) 19 selenoproteins (GPX1, GPX2, GPX3, GPX4, GPX6, Dio3, Txnrd2, Txnrd3, SEPHS2, SEL15, SELH, SELI, SELM, SELN, SELO, SELS, SELT, SELV, and SELW), while Dio2, SELK, Txnrd1, and MSRB1 were not affected by Se deficiency (p ≥ 0.05). In addition, Se deficiency led to increased intracellular ROS content, p-P38 and p-JNK gene expression levels (p < 0.05), the mitochondrial apoptosis pathway Bax, Casp9 and Cle-Casp3 protein expression levels (p < 0.05), and decreased Bcl2 protein expression level (p < 0.05), simultaneously, increased necroptosis marker genes RIP1, RIP3, and MLKL protein expression levels (p < 0.05) with a dose-dependent pattern. The above results indicate that Se deficiency induces HUSMCs apoptosis and necroptosis through the ROS/MAPK pathway and is closely related to selenoproteins.

Erythropoietin Resistance Development in Hemodialysis Patients: The Role of Oxidative Stress

Oxidative stress (OS) is considered a significant risk factor for the development of anemia in patients treated by regular hemodialysis (HD). Moreover, OS represents a risk factor for the development of erythropoietin (EPO) resistance in these patients. The aim of this study was to examine the role of OS regarding EPO resistance development in patients treated by regular HD. 96 patients treated with standard HD and on-line hemodiafiltration were included in this study. The patients were treated with short-acting and long-acting EPOs for anemia. The concentration of superoxide anion radical, hydrogen peroxide, thiobarbituric acid reactive substances, and nitric oxide in the form of nitrites and the activity of catalase, superoxide dismutase and reduced glutathione were measured in patients' blood spectrophotometrically. Standard biochemical analysis, inflammatory markers, nutritional status, HD parameters, and erythropoietin resistance index were also determined. Patients with resistance to short-acting EPO had significantly lower concentration of hemoglobin in the blood and hematocrit value, a significantly higher serum ferritin concentration, and significantly lower catalase activity in erythrocytes than patients without EPO resistance. Patients with resistance to long-acting EPO have a significantly lower hemoglobin concentration in the blood, hematocrit values, and serum concentration of prealbumin and vitamin D, as well as significantly higher concentration of C-reactive protein, superoxide anion, and hydrogen peroxide concentration than those without resistance. OS significantly contributes to EPO resistance development. OS, higher ferritin and CRP levels, lower hemoglobin, hematocrit and prealbumin levels, and vitamin D deficiency represent significant risk factors for EPO resistance development in HD patients.

Potential Benefits of Pila ampullacea, Tempeh, Moringa oleifera Leaves as Nutritional Support for Hemodialysis

Background:

Hemodialysis patients can experience problems, including protein-energy malnutrition, infection, disorders of the immune system, and inflammation. One etiology of malnutrition in hemodialysis is inadequate energy and protein intake, making patients need nutritional support, which can be fulfilled by local Indonesian foodstuffs.

Objective:

This paper aimed to review the potential health benefits of snails (Pila ampullacea), tempeh, and Moringa oleifera leaves as nutritional support for hemodialysis patients.

Methods:

In this review, the methodology used was based on comprehensive data searched from PubMed for literature review and technology benchmarking in making nutritional support for hemodialysis patients. An in-depth discussion, including the advantages and drawbacks of each foodstuff, is presented and outlined. Furthermore, key solutions are proposed and presented to overcome hemodialysis issues.

Results:

The mixture of snail, tempeh, and moringa leaves as nutritional support for hemodialysis patients shows a good combination of natural ingredients from animals and plants. The nutritional content of the three mixed ingredients is found to meet the dietary requirements of hemodialysis, which are high protein, calcium and antioxidants, low phosphorus, and a phosphorus-to-protein ratio of <16.

Conclusion:

The combination of snails, tempeh, and moringa leaves provides several potential health benefits in overcoming nutritional problems, decreased immune status, and inflammation of hemodialysis patients.

A Comparative Study of the Efficacy of an Intervention with a Nutritional Supplement for Patients with Chronic Kidney Disease: A Randomized Trial

Chronic kidney disease (CKD) involves heterogeneous diseases that affect the renal structure and function. Malnutrition plays a crucial role during patients with CKD on hemodialysis (HD) treatment and is associated with an increased rate and duration of hospitalizations. The aim of this randomized, parallel, intervention-controlled trial was to assess whether the use of daily supplementation with a new nutritional product developed by the Grand Fontaine Laboratories improves the nutritional status and anthropometric parameters of stage 5 CKD patients, compared with standard renal dietary advice, after three months of follow-up. Dietary intake, anthropometric measurements, physical activity, and blood samples were collected at baseline and after three months of intervention. Significant improvements were observed within the intervention group in body weight (1.5 kg [95% CI: 0.9 to 2.12 kg]) and BMI (0.54 kg/m² [95% CI: 0.31 to 0.77]; p-value between groups, 0.002 and 0.006, respectively). In the control group, significant decreases were observed in transferrin saturation (-5.04% [95% CI: -8.88 to -1.21]) and alpha-tocopherol levels (-3.31 umol/L [95% CI: -6.30 to -0.32]). We concluded that daily dietary intake of a specific renal nutritional complement in CKD patients with or at risk of malnutrition may prevent deterioration in nutritional parameters.

Comparison of the Nutritional Status Assessment Methods for Hemodialysis Patients

Protein-energy wasting (PEW) is prevalent among hemodialysis (HD) patients and is associated with poor outcomes. There are various methods for nutritional status evaluation in HD patients. Each method has its own advantages and disadvantages. We aimed at comparing the method validities of normalized protein catabolic ratio (nPCR) and malnutrition universal screening tool (MUST) with subjective global assessment (SGA) in HD patients. We examined 88 HD patients using SGA and MUST questionnaires. The nPCRs were calculated using pre-dialysis and post-dialysis BUN and Kt/v. Also, PEW of patients was assessed based on the criteria of the International Society of Renal Nutrition and Metabolism. Methods' specificity, sensitivity, and precision rates were assessed. Correlations between methods were analyzed using Pearson-correlation. Based on the SGA, MUST, and nPCR methods, almost 41%, 30%, and 60% of patients had malnutrition, respectively. According to the criteria, more than 90% of patients had PEW. SGA was positively and significantly associated with MUST (p ≤ 0.001). Sensitivity for SGA, MUST, and nPCR methods were 100%,100%, 1.8%, and their specificity were 98%, 98%, and 4%, and their precision rates were 99.7%, 98.7%, and 3%, respectively. From various methods of nutritional assessment (SGA, MUST, and nPCR), compared to SGA as the common method of nutrition assessment in hemodialysis patients, MUST had the nearest specificity, sensitivity, and precision rate and nPCR method had the lowest ones. nPCR seems to be a flawed marker of malnutrition and it should be more investigated if MUST can be used instead of SGA.

Associations Between Blood Trace Element Levels and Nutritional Status in Maintenance Hemodialysis

OBJECTIVE(S)

We aimed to investigate the associations between blood trace element levels and nutritional status in patients undergoing maintenance hemodialysis (MHD).

METHODS

This cross-sectional study included patients undergoing MHD who were treated at our center in September 2019. Clinical and demographic data and blood samples were collected before hemodialysis sessions, and the levels of manganese, lead, selenium, zinc, and copper were measured by inductively coupled plasma mass spectrometry. The Simplified Nutritional Appetite Questionnaire scale was used to assess patient appetite. Skinfold thickness, bicep circumference, upper arm muscle circumference, 7-point Subjective Global Assessment, Nutritional Risk Screening 2002 (NRS 2002), and Geriatric Nutritional Risk Index (GNRI) were used to assess patient nutritional status. Univariate and multivariate logistic regression analyses were performed to study the relationship between trace elements and nutritional indicators.

RESULTS

In total, 118 patients (64 males and 54 females) were included, with a median dialysis vintage of 34.0 months (16.0-54.5 months) and an average age of 63.20 ± 14.26 years. Malnourished patients, as defined by the GNRI, Subjective Global Assessment, and NRS 2002, accounted for 28.0%, 49.2%, and 26.3% of enrolled patients, respectively. The multivariate binary logistic regression showed that higher blood copper levels were independently associated with nutritional risk defined as GNRI ≤91.2 (odds ratio [OR] = 1.003, 95% confidence interval [CI] = 1.000-1.006; P = .020), whereas lower blood zinc levels (OR = 0.634, 95% CI = 0.439-0.916; P = .015), blood zinc < 4.220 mg/L (OR = 3.723, 95% CI = 1.274-10.879; P = .016), lower blood selenium levels (OR = 0.959, 95% CI = 0.929-0.990; P = .010), and blood selenium < 85 μg/L (OR = 5.568, 95% CI = 1.039-29.840; P = .045) were independently associated with a nutritional risk defined as NRS 2002 ≥ 3.

CONCLUSION(S)

Higher levels of blood copper and lower levels of blood zinc and selenium were independently associated with higher nutritional risk in MHD patients.

Levels of trace blood elements associated with severe sleep disturbance in maintenance hemodialysis patients

PURPOSE

Sleep disturbance is frequently observed in patients on maintenance hemodialysis (MHD), and this population usually presents imbalances in trace elements. We investigated the association between blood trace element levels and sleep quality in patients on MHD.

METHODS

This cross-sectional and single-center study was performed in September 2019. Patients regularly undergoing hemodialysis for > 3 months at our center were recruited, and demographic, clinical, and laboratory parameters were recorded. The Pittsburgh Sleep Quality Index (PSQI) was applied to define sleep disturbance. Blood trace element (zinc, manganese, copper, selenium, and lead) levels were measured using an inductively coupled plasma mass spectrometer.

RESULTS

In total, 121 patients on MHD (male/female = 68:53) were enrolled in the study (mean age 63.7 ± 13.9 years, median dialysis vintage 38.0 [20.0, 60.0] months). According to PSQI, 56 (46%) patients experienced severe sleep disturbance. These patients were characterized by older age, higher serum parathyroid hormone levels, and lower blood selenium levels (all P < 0.05). No significant differences in blood zinc, manganese, copper, and lead levels were observed between groups. Univariate binary logistic regression showed that lower blood selenium levels were associated with severe sleep disturbance (odds ratio = 0.976, 95% confidence interval: 0.954-0.999, P = 0.038). Multivariate analyses also confirmed the results after adjusting for confounding factors.

CONCLUSION

Our study indicated an association between lower blood selenium levels and the occurrence of severe sleep disturbances in patients on MHD. However, a prospective study with a larger sample size and assessing the importance of selenium supplementation are needed to confirm the results.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

The effect of hemodialysis, peritoneal dialysis and renal transplantation on nutritional status and serum micronutrient levels in patients with end-stage renal disease; Multicenter, 6-month period, longitudinal study

PURPOSE

Nutritional status and micronutrient levels of end stage renal disease (ESRD) patients may vary depending on the mode of renal replacement therapy (RRT). We aimed to compare the effects of hemodialysis, peritoneal dialysis (PD) and renal transplantation (RT) on micronutrient levels and nutritional status in ESRD patients.

PATIENTS AND METHODS

A total of 77 ESRD patients who had not received RRT were included in this prospective longitudinal study. All ESRD patients underwent a blood serum analysis that assessed the micronutrients such as selenium, copper, zinc, chromium, retinol, thiamine and vitamin B6 as well as a nutritional status assessment. After the baseline assessments and the initiation of RRT was accomplished, all patients were followed for 6 months.

RESULTS

The study showed significant improvements in subjective global assessment scores (percentage increases in score A were 26.6 and 36.6; p = 0.039 and p = 0.001; respectively), mid-arm circumference and the skin-fold thicknesses (p < 0.001, p < 0.001; respectively) in the RT and hemodialysis groups. The examinations at sixth month revealed a significant increase in body weight (4.8 kg; p = 0.002) and albumin levels (0.6 g/dL; p < 0.001) in only RT group. Zinc, thiamin and vitamin B6 were the most deficient micronutrients (44.1 %, 24.7 % and 35.1 %; respectively) in ESRD patients. There was a significant increase in selenium and retinol levels (p = 0.020 and p < 0.001; respectively) but a significant decrease in thiamin levels (p = 0.041) in RT patients. A significant increase in retinol levels (p = 0.028) and a significant decrease in thiamin levels (p = 0.022) was observed in the hemodialysis patients. However, no significant change in micronutrient levels was observed in the PD patients.

CONCLUSION

The results support the recommendation that ESRD patients should be supplemented with water-soluble vitamins, especially thiamine and vitamin B6, and trace elements, especially zinc. RT appears to be superior to other modes of RRT when examining SGA score, anthropometric measurements, albumin and micronutrient levels.

Influence of selenium supplementation on carbohydrate metabolism and oxidative stress in pregnant women with gestational diabetes mellitus

BACKGROUND

In the presence of conflicting advice about the relationship between selenium-type II diabetes-oxidative stress trio, this study aimed to assess the consequences of selenium supplementation on fasting plasma glucose (FPG) level, antioxidant activities of selenodependent and non-selenodependent enzymes, and other markers of oxidative stress studied for the first time during gestational diabetes mellitus (GDM).

METHODS

This research was carried out among 180 pregnant Algerian women, 60 of whom were in good health, 60 women with GDM did not take supplements, and 60 women with GDM took selenium orally (50 mg/d) for 12 weeks starting from their second trimester of pregnancy. Blood samples were taken in order to assay FPG level and oxidative stress markers.

RESULTS

Selenium supplementation during GDM has demonstrated its hypoglycemic power in the significant decline of FPG level, and its antioxidant properties in the significant reinforcement of antioxidant activities of erythrocyte selenodependent enzymes (glutathione peroxidase and glutathione reductase), the significant increase in erythrocyte catalase and superoxide dismutase activities simultaneously with the highest decrease in erythrocyte and plasma malondialdehyde levels. This decrease was only significant for plasma carbonyl proteins, which was not the case for erythrocyte carbonyl proteins.

CONCLUSIONS

The recourse to selenium supplementation by seleno-deficient pregnant women with GDM is beneficial for maternal health. This micronutrient exploits its antioxidant and insulin-mimetic properties in the maintenance of blood glucose homeostasis and the fight against oxidative stress, and consequently, its supplementation delays the occurrence of GDM complications.

Effects of Selenium Supplementation on Metabolic Status in Patients Undergoing for Coronary Artery Bypass Grafting (CABG) Surgery: a Randomized, Double-Blind, Placebo-Controlled Trial

This study was carried out to evaluate the effects of selenium supplementation on glycemic control, lipid profiles, and biomarkers of inflammation and oxidative stress in patients undergoing for coronary artery bypass grafting (CABG) surgery. This randomized, double-blind, placebo-controlled trial was performed among 33 patients undergoing for CABG surgery, aged 40-85 years old. Subjects were randomly allocated into two groups to intake either 200 μg/day selenium supplements as selenium yeast (n = 17) or placebo (n = 16) for 4 weeks. Glycemic control, lipid profiles, and biomarkers of inflammation and oxidative stress were assessed at baseline and at the end of trial. After the 4-week intervention, selenium supplementation significantly decreased fasting plasma glucose (FPG) (β, 6.76 mg/dL; 95% CI, - 13.13, - 0.40; P = 0.03), insulin (β, - 1.14 μIU/mL; 95% CI, - 2.01, - 0.28; P = 0.01); homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (β - 0.35; 95% CI, - 0.62, - 0.08; P = 0.01); and total-/HDL-cholesterol ratio (β - 0.31; 95% CI, - 0.51, - 0.09; P = 0.008); and significantly increased HDL-cholesterol levels (β, 2.72 mg/dL; 95% CI, 0.89, 4.55; P = 0.005) compared with the placebo. Moreover, selenium supplementation led to a significant reduction in high-sensitivity C-reactive protein (hs-CRP) (β, - 0.68 mg/L; 95% CI, - 1.18, - 0.17; P = 0.01) and malondialdehyde (MDA) (β, - 0.27 μmol/L; 95% CI, - 0.47, - 0.07; P = 0.009), and a significant elevation in total glutathione (GSH) levels (β, 77.33 μmol/L; 95% CI, 56.11, 98.55; P < 0.001) compared with the placebo. Selenium supplementation did not affect other metabolic profiles. Overall, our study demonstrated that selenium supplementation for 4 weeks to patients undergoing for CABG surgery had beneficial effects on FPG, insulin, HOMA-IR, total-/HDL-cholesterol ratio, HDL-cholesterol, hs-CRP, GSH, and MDA levels, but did not affect other metabolic profiles. Clinical trial registration number: http://www.irct.ir : IRCT2017090533941N22.

Selenium, aging and aging-related diseases

Selenium is an essential trace element in the human body and plays an important role in the body via selenoprotein, which contains selenium. Selenoproteins (glutathione peroxidase, thioredoxin reductase, methionine sulfoxide reductase1 and endoplasmic reticulum-selenoproteins, etc.) have antioxidant effects and are involved in regulating antioxidant activities. Aging is an inevitable process and is always accompanied by aging-related diseases. Reactive oxygen species are important initial factors in aging and aging-related diseases. Selenium contributes to the alleviation of reduced reactive oxygen species-mediated inflammation, reduced DNA damage and prolonged telomere length and thereby plays roles in fighting aging and preventing aging-related diseases. In the elderly, aging-related diseases include neuropsychiatric diseases, tumors, cardiovascular diseases, and skin aging, among others. Selenium supplementation is an important strategy for anti-aging and the prevention of aging-related diseases and is of great significance for the elderly. However, with the accumulation of related research, selenium supplementation does not necessarily contribute to the prevention of aging and aging-related diseases. It is believed that a low level of selenium is beneficial to the human body. Thus, the effect of selenium on human aging and aging-related diseases is still controversial. This paper reviews the research progress and objective role of selenium in aging and aging-related diseases.

Antioxidant Supplementation in Renal Replacement Therapy Patients: Is There Evidence?

The disruption of balance between production of reactive oxygen species and antioxidant systems in favor of the oxidants is termed oxidative stress (OS). To counteract the damaging effects of prooxidant free radicals, all aerobic organisms have antioxidant defense mechanisms that are aimed at neutralizing the circulating oxidants and repair the resulting injuries. Antioxidants are either endogenous (the natural defense mechanisms produced by the human body) or exogenous, found in supplements and foods. OS is present at the early stages of chronic kidney disease, augments progressively with renal function deterioration, and is further exacerbated by renal replacement therapy. End-stage renal disease patients, on hemodialysis (HD) or peritoneal dialysis (PD), suffer from accelerated OS, which has been associated with increased risk for mortality and cardiovascular disease. During HD sessions, the bioincompatibility of dialyzers and dialysate trigger activation of white blood cells and formation of free radicals, while a significant loss of antioxidants is also present. In PD, the bioincompatibility of solutions, including high osmolality, elevated lactate levels, low pH, and accumulation of advanced glycation end-products trigger formation of prooxidants, while there is significant loss of vitamins in the ultrafiltrate. A number of exogenous antioxidants have been suggested to ameliorate OS in dialysis patients. Vitamins B, C, D, and E, coenzyme Q10, L-carnitine, a-lipoic acid, curcumin, green tea, flavonoids, polyphenols, omega-3 polyunsaturated fatty acids, statins, trace elements, and N-acetylcysteine have been studied as exogenous antioxidant supplements in both PD and HD patients.

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.

Efficacy of Nutritional Interventions on Inflammatory Markers in Haemodialysis Patients: A Systematic Review and Limited Meta-Analysis

Low-grade chronic inflammation is prevalent in patients undergoing haemodialysis (HD) treatment and is linked to the development of premature atherosclerosis and mortality. The non-pharmacological approach to treat inflammation in HD patients through nutritional intervention is well cited. We aimed to assess the efficacy of different nutritional interventions at improving inflammatory outcomes in HD patients, based on markers such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α). We searched PubMed, Cochrane Library, and Embase for randomized controlled trials (RCT) published before June 2017. Inclusion criteria included RCTs on adult patients on maintenance HD treatment with duration of nutritional interventions for a minimum 4 weeks. Risk of bias was assessed using the Jadad score. In total, 46 RCTs experimenting different nutritional interventions were included in the review and categorized into polyphenols rich foods, omega-3 fatty acids, antioxidants, vitamin D, fibres, and probiotics. Meta-analyses indicated significant reduction in CRP levels by omega-3 fatty acids (Random model effect: -0.667 mg/L, p < 0.001) and vitamin E (fixed model effect: -0.257 mg/L, p = 0.005). Evidence for other groups of nutritional interventions was inconclusive. In conclusion, our meta-analysis provided evidence that omega-3 fatty acids and vitamin E could improve inflammatory outcomes in HD patients.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

Comparative Study on Trace Element Excretions between Nonanuric and Anuric Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

Few studies have been reported on alterations of trace elements (TE) in peritoneal dialysis patients. Our objective was to investigate and assess the characteristics of daily TE excretions in continuous ambulatory peritoneal dialysis (CAPD) patients. This cross-sectional study included 61 CAPD patients (nonanuric/anuric: 45/16) and 11 healthy subjects in Wuhan, China between 2013 and 2014. The dialysate and urine of patients and urine of healthy subjects were collected. The concentrations of copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo), and arsenic (As) in dialysate and urine were determined using inductively coupled plasma mass spectrometer (ICP-MS). Various clinical variables were obtained from automatic biochemical analyzer. Daily Cu, Zn, Se, and Mo excretions in nonanuric patients were higher than healthy subjects, while arsenic excretion in anuric patients was lower. A strong and positive correlation was observed between Se and Mo excretion in both dialysate (β = 0.869, p < 0.010) and urine (β = 0.968, p < 0.010). Furthermore, the clinical variables associated with Se excretion were found to be correlated with Mo excretion. Our findings indicated that nonanuric CAPD patients may suffer from deficiency of some essential TEs, while anuric patients are at risk of arsenic accumulation. A close association between Se and Mo excretion was also found.

The effects of selenium supplementation on biomarkers of inflammation and oxidative stress in patients with diabetic nephropathy: a randomised, double-blind, placebo-controlled trial

This study was carried out to assess the effects of Se supplementation on biomarkers of inflammation and oxidative stress in patients with diabetic nephropathy (DN). This randomised, double-blind, placebo-controlled clinical trial was conducted among sixty patients with DN. Patients were randomly divided into two groups to take either 200 µg/d Se supplements as Se yeast (n 30) or placebo (n 30) for 12 weeks. In unadjusted analyses, compared with the placebo, Se supplementation led to a significant reduction in high-sensitivity C-reactive protein (hs-CRP) (-1069·2 (sd 1752·2) v. -135·3 (sd 1258·9) ng/ml, P=0·02), matrix metalloproteinase-2 (MMP-2) (-612·3 (sd 679·6) v. +76·0 (sd 309·1) ng/ml, P<0·001) and plasma malondialdehyde (MDA) concentrations (-0·1 (sd 0·7) v. +0·4 (sd 0·9) µmol/l, P=0·01). In addition, a significant increase in plasma total antioxidant capacity (TAC) (+174·9 (sd 203·9) v. +15·8 (sd 382·2) mmol/l, P=0·04) was observed following supplementation with Se compared with the placebo. Subjects who received Se supplements experienced a borderline statistically significant decrease in serum protein carbonyl (PCO) levels (P=0·06) compared with the placebo. When we adjusted the analysis for baseline values of biochemical parameters, age and BMI, serum hs-CRP (P=0·14) and MDA levels (P=0·16) became non-significant, whereas plasma nitric oxide (NO) (P=0·04) and glutathione (GSH) (P<0·001) became statistically significant, and other findings did not change. Supplementation with Se had no significant effect on NO, transforming growth factor β (TGF-β), advanced glycation end products (AGE), PCO and GSH compared with the placebo. Overall, our study demonstrated that Se supplementation among DN patients had favourable effects on serum MMP-2, plasma NO, TAC and GSH, but did not affect hs-CRP, TGF-β, AGE, PCO and MDA.

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.

Intradialytic Oral Protein Supplementation and Nutritional and Inflammation Outcomes in Hemodialysis: A Randomized Controlled Trial

BACKGROUND

Malnutrition is a common finding in hemodialysis patients and can increase oxidative stress and inflammation levels.

STUDY DESIGN

A randomized, controlled, nonblinded, parallel trial.

SETTING & PARTICIPANTS

92 hemodialysis patients from a single center with malnutrition according to subjective global assessment (SGA) score (SGA score > 7).

INTERVENTION

3 treatment groups (23 patients each) received 220mL of fermented vitamin E-fortified whey beverage (15g of whey protein concentrate + 600IU of vitamin E) or 220mL of fermented whey beverage (15g of whey protein concentrate) or vitamin E (600IU) 3 times a week for 8 weeks. The control group (23 patients) received no intervention.

OUTCOME & MEASUREMENTS

Primary outcomes were change in SGA score and malnutrition-inflammation score (MIS) from baseline to the end of the trial.

RESULTS

At the end of the study, 83 patients were analyzed (2, 3, 1, and 3 patients left the study in the vitamin E-fortified whey beverage, whey beverage, vitamin E, and control groups, respectively). Changes in SGA scores were -3.48 (95% CI, -4.90 to -2.00), -3.22 (95% CI, -4.13 to -2.30), -1.70 (95% CI, -3.20 to -0.24), and 1.56 (95% CI, 0.60 to 2.50) for the vitamin E-fortified whey beverage, whey beverage, vitamin E, and control groups, respectively (overall P<0.001; P≤0.001 for each treatment group vs control). Changes in MISs were -3.17 (95% CI, -4.40 to -1.90), -1.83 (95% CI, -2.50 to -1.10), -2.30 (95% CI, -3.50 to -1.10), and 1.48 (95% CI, 0.65 to 2.30) for the vitamin E-fortified whey beverage, whey beverage, vitamin E, and control groups, respectively (overall P<0.001; P<0.001 for each treatment group vs control). Few adverse effects were reported in any group.

LIMITATIONS

Lack of blinding, small sample size, and short duration.

CONCLUSIONS

Whey protein in the form of a new fermented whey beverage and vitamin E supplementation may improve SGA score and MIS in the short term.

Selenium Supplementation and the Effects on Reproductive Outcomes, Biomarkers of Inflammation, and Oxidative Stress in Women with Polycystic Ovary Syndrome

Selenium supplementation could be effective on reproductive outcomes, biomarkers of inflammation, and oxidative stress among women with polycystic ovary syndrome (PCOS). The aim of the study was to determine the effects of selenium supplementation on reproductive outcomes, biomarkers of inflammation, and oxidative stress in PCOS patients. The present randomized double-blind, placebo-controlled trial was conducted on 64 women aged 18-40 years old with PCOS at the clinic affiliated to Ardabil University of Medical Sciences, Ardabil, Iran. The participants were randomly assigned to 2 groups receiving either 200 μg selenium daily (n=32) or placebo (n=32) for 8 weeks. Hormonal profiles, biomarkers of inflammation, and oxidative stress were measured and compared both before and after the treatment. After 8 weeks of intervention, pregnancy rate in the selenium group was higher than in the placebo group: 18.8 (6/32) vs. 3.1% (1/32), p=0.04. In addition, alopecia (40.6 vs. 9.4%, p=0.004) and acne (46.9 vs. 12.5 %, p=0.003) decreased following the consumption of selenium supplements compared with placebo. Additionally, patients who received selenium supplements had significantly decreased serum dehydroepiandrosterone (DHEA) levels (p=0.02), hirsutism (modified Ferriman-Gallwey scores) (p<0.001), serum high sensitivity C-reactive protein (hs-CRP) (p=0.02), and plasma malondialdehyde (MDA) levels (p=0.01) compared with placebo. We did not observe any significant effects of taking selenium supplements on other hormonal profiles, nitric oxide (NO), and other biomarkers of oxidative stress. Taken together, selenium supplementation for 8 weeks among PCOS women had beneficial effects on reproductive outcomes, DHEA, hs-CRP, and MDA levels. Supporting Information for this article is available online at http://www.thieme-connect.de/products.

The onset of lipid peroxidation in rheumatoid arthritis: consequences and monitoring

Several epidemiological studies propose the association of rheumatoid arthritis (RA) with oxidative stress. The aim of this study was to estimate the possible onset of systemic lipid peroxidation in RA patients and its relevance for pathophysiology and monitoring of RA. Seventy-three patients with RA and 73 healthy subjects were included in the study. Lipid peroxidation was estimated by the measurement of 4-hydroxynonenal (4-HNE), 4-hydroxyhexenal, malondialdehyde, acrolein, crotonaldehyde, 4-oxononenal, and isoprostanes (8-isoPGF(2α)) levels. Cytosolic phospholipase A(2) (cPLA(2)), platelet-activating factor acetylhydrolase (PAF-AH) and glutathione peroxidase (GSH-Px) activities and vitamin E levels were also determined. In parallel, the plasma levels of phospholipid arachidonic acid (AA), linoleic acid (LA), and 4-HNE-protein adducts were monitored. Plasma of RA patients had increased vitamin E levels, but decreased GSH-Px activity and phospholipid AA and LA levels when compared to levels of the healthy subjects. The levels of aldehydes were significantly increased in the plasma of the RA patients and even more in urine. Significant increases in HNE-modified protein adducts was observed for the first time in plasma of RA patients, while the activities of PAF-AH and cPLA(2) were decreased. The 8-isoPGF(2α) levels were 9-fold higher in plasma and 3-fold higher in urine of RA patients and were related to the severity of disease. The levels of lipid peroxidation products in plasma and in urine suggest the relationship between lipid peroxidation and the development of RA. Additionally, urine 8-isoPGF(2α), plasma 4-HNE and 4-HNE-protein adducts appear to be convenient biomarkers to monitor progression of this autoimmune disease.