Omega-3 fatty acids supplementation does not affect serum lipids in chronic hemodialysis patients

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.

Effects of omega-3 supplementation on serum albumin, pre-albumin and the CRP/albumin ratio in hospitalized patients: a systematic review and meta-analysis

CONTEXT

Low serum albumin and pre-albumin concentrations are associated with edema, infection, thrombosis, heart failure, and mortality.

OBJECTIVE

This comprehensive systematic review and meta-analysis of clinical trials was conducted to summarize the available findings on the impact of omega-3 supplementation on albumin, pre-albumin, and the C-reactive protein/albumin ratio in hospitalized patients.

DATA SOURCES

PubMed, Web of Science, Scopus, and Google Scholar databases were searched from January 1990 to October 2021.

DATA EXTRACTION

Extracted data from 50 randomized controlled trials (RCTs) with a total number of 3196 participants were analyzed using the random-effects model. The dose-dependent effect was also evaluated.

DATA ANALYSIS

Oral omega-3 supplementation significantly increased serum albumin concentrations in patients with cancer (weighted mean difference [WMD]: 0.19; 95% CI: 0.05, 0.33, P= 0.006), patients on dialysis (WMD: 0.14; 95% CI: 0.01, 0.28, P= 0.042), and those with hypoalbuminemia (WMD: 0.38; 95% CI: 0.03, 0.72, P = 0.033); however, there was no significant effect among patients with gastrointestinal or hepatologic diseases. Moreover, each 1000 mg/day increase in oral omega-3 supplementation resulted in elevated serum albumin levels in cancer patients (WMD: 0.15; 95% CI: 0.07, 0.24, P < 0.001). In addition, a favorable effect of oral omega-3 supplementation on pre-albumin levels was observed among patients with cancer (WMD: 33.87; 95% CI: 12.34, 55.39, P = 0.002). A similar significant effect of parenteral omega-3 supplementation on pre-albumin concentrations was seen among those with gastrointestinal and hepatologic diseases as well (WMD: 23.30; 95% CI: 13.58, 33.03, P < 0.001). No significant effect of oral omega-3 supplementation on the CRP/albumin ratio was found.

CONCLUSIONS

Overall, omega-3 fatty acids supplementation resulted in a favorable change in serum albumin and pre-albumin concentrations in hospitalized patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021285704.

A Consistency Model for Identifying the Effects of n-3 and n-6 Fatty Acids on Lipoproteins in Dialysis Patients

Numerous randomized controlled trials (RCTs) and meta-analyses have assessed the effects of supplemental dietary polyunsaturated fatty acids (PUFAs) on levels of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) and the LDL/HDL ratio in patients receiving renal replacement therapy (RRT). However, results are ambiguous due to mixed reports of various nutrients used in the intervention group. We performed a network meta-analysis of RCTs to assess the effects of PUFAs on lipid profiles in patients undergoing RRT. RCTs performed before November 2021 were gathered from three databases. The means, standard deviations and the number of cases for each arm were independently extracted by two authors to form a network meta-analysis of LDL and HDL levels and the LDL/HDL ratio in a random effects model. Twenty-eight RCTs (n = 2017 subjects) were included in this study. The pooled results revealed that the combination of omega-3 fatty acids (n-3) and omega-6 fatty acids (n-6) produced significantly lower LDL (standardized mean difference (SMD) = −1.43, 95% confidence interval: −2.28 to −0.57) than the placebo. Both n-3 fatty acids (SMD = 0.78) and the combination of n-3 + n-6 (SMD = 1.09) benefited HDL significantly compared with placebo. Moreover, n-3 alone also exhibited a significantly lower LDL/HDL ratio than placebo. Collectively, PUFAs seem to be adequate nutrients for controlling lipoproteins in patients undergoing RRT. Specifically, n-3 + n-6 supplementation improved LDL levels, while n-3 improved HDL levels and the LDL/HDL ratio. However, our data provide limited information on specific dosages of PUFAs to form a concrete recommendation.

Effects of Omega-3 Fatty Acid Intake in Patients Undergoing Dialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective: Fish oil supplementation has been shown to be beneficial for hemodialysis (HD) patients. The aim of this study was to evaluate the efficacy and safety of omega-3 fatty acid supplementation or dietary adjustment in dialysis patients.Methods: A systematic literature search was performed to identify relevant randomized controlled trials (RCTs) to study the effects of omega-3 supplementation on dialysis patients. The variables of interest included the levels of blood lipids, inflammatory indicators, proteins, parathyroid hormone (PTH), gastrointestinal adverse reactions, and all-cause mortality. The mean differences (MDs) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed with the I² test. Subgroup and sensitivity analyses were performed to identify potential sources.Results: The systematic review included 49 RCTs and evaluated the efficacy and safety of omega-3 fatty acid supplementation in dialysis patients. Data synthesis showed that compared with the control group, the group receivingomega-3 supplementation exhibited significantly decreased serum triglyceride (TG) levels, decreased C-reactive protein (CRP) and TNF-alpha levels, increased hemoglobin levels, reduced serum phosphorus levels, increased PTH levels, and increased gastrointestinal adverse reactions to a certain extent. Furthermore, there was no effect on the blood total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), albumin or calcium levels and all-cause mortality.Conclusion: Omega-3 fatty acid supplementation is related to a reduction in serum TG, LDL and inflammation index levels and has few adverse reactions. Therefore, omega-3 fatty acid supplementation may be a useful nutrition therapy for dialysis patients.

Dietary Lipids and Dyslipidemia in Chronic Kidney Disease

The progression of chronic kidney disease (CKD) leads to altered lipid metabolism. CKD patients exhibit high blood triglyceride (TG) levels, reduced concentrations and functionality of high-density lipoproteins (HDL), and elevated levels of atherogenic small, dense, low-density lipoproteins (sdLDL). Disorders of lipid metabolism and other metabolic disturbances place CKD patients at high risk for cardiovascular disease (CVD). Extensive evidence supports the cardioprotective effects of unsaturated fatty acids, including their beneficial effect on serum cholesterol and TG levels. Dietary lipids might therefore be especially important in the nutritional management of CKD. We review current dietary recommendations for fat intake by CKD patients and suggest potential nutritional interventions by emphasizing dietary lipids that might improve the blood lipid profile and reduce cardiovascular risk in CKD.

The effect of fish oil on inflammation markers in adult patients undergoing hemodialysis: A meta-analysis

OBJECTIVE

This meta-analysis was to assess the effect of fish oil supplementation on inflammation markers in adult patients receiving hemodialysis.

METHODS

CENTRAL, EMBASE, MEDLINE databases were searched from inception to 10 April 2020. Two authors independently searched, selected, and screened the literature. The pooled results are represented by WMD or SMD with 95% confidence intervals. Subgroup analysis and meta-regression were used to explore sources of heterogeneity, and sensitivity analysis was used to assess the robustness of the pooled results. Funnel plots were used to assess publication bias.

RESULTS

Eleven RCT (randomized control trials) studies were included. The pooled results showed that fish oil supplementation caused a significant reduction of the CRP(C-reactive protein) level (random model: WMD, -3.36, 95%CI: -5.46 to -1.26, P = .002), especially in patients with baseline CRP ≥ 5 mg/L (random model: WMD, -4.43, 95%CI: -6.10 to -2.76, P = .00001, I²  = 41%). Meta-regression analyses showed that CRP baseline level (CRP < 5 mg/L) was the main source of heterogeneity (P = .036). Sensitive analyses revealed that the result was hardly changed. Fish oil supplementation might not reduce the level of IL-6 (random model: WMD, -2.26, 95%CI: -19.61 to 15.09, P = .80) in four studies or the level of TNF-α (random model: SMD, -2.51, 95%CI: -6.08 to 1.06, P = .17) in three studies.

CONCLUSIONS

Fish oil supplementation could reduce the level of CRP in hemodialysis patients, especially in patients with CRP ≥ 5 mg/L, but had no effects on IL-6 and TNF-α.

Fish oil plus wheat germ oil have no prominent effect on homocysteine levels and nutritional indices in hemodialysis patients

Background: Elevated homocysteine levels and malnutrition are frequently detected in hemodialysis patients and are believed to exacerbate cardiovascular comorbidities. Omega-3 fatty acids have been postulated to lower homocysteine levels by up-regulating metabolic enzymes and improving substrate availability for homocysteine degradation. Additionally, it has been suggested that prevention of folate depletion by vitamin E consumption decreases homocysteine levels. However, data on the effect of omega-3 fatty acids and/or vitamin E on homocysteine levels and nutritional status have been inconclusive. Therefore, this study was planned to examine the effect of combined supplementation of fish oil, as a source of omega-3 fatty acids, with wheat germ oil, as a source of vitamin E, on homocysteine and nutritional indices in hemodialysis patients. Methods: This study was a randomized, double-blind, placebo-controlled trial. Forty-six hemodialysis patients were randomly assigned to two equally-sized groups; a supplemented group who received 3000 mg/day of fish oil [1053 mg omega-3 fatty acids] plus 300 mg/day of wheat germ oil [0.765 mg vitamin E], and a matched placebo group who received placebo capsules for 4 months. Serum homocysteine and different nutritional indices were measured before and after the intervention. Results: Twenty patients in each group completed the study. At the end of the study, there were no significant changes in homocysteine levels and in the nutritional indices neither in the supplemented nor in the placebo-control groups (p > 0.05). Conclusions: Fish oil and wheat germ oil combination did not produce significant effects on serum homocysteine levels and nutritional indices of hemodialysis patients.

Efficacy of Polyunsaturated Fatty Acids on Inflammatory Markers in Patients Undergoing Dialysis: A Systematic Review with Network Meta-Analysis of Randomized Clinical Trials

The effects of polyunsaturated fatty acids (PUFAs) on inflammatory markers among patients receiving dialysis have been discussed for a long time, but previous syntheses made controversial conclusion because of highly conceptual heterogeneity in their synthesis. Thus, to further understanding of this topic, we comprehensively gathered relevant randomized clinical trials (RCTs) before April 2019, and two authors independently extracted data of C-reactive protein (CRP), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) for conducting network meta-analysis. Eighteen eligible RCTs with 962 patients undergoing dialysis were included in our study. The result showed that with placebo as the reference, PUFAs was the only treatment showing significantly lower CRP (weighted mean difference (WMD): −0.37, 95% confidence interval (CI): −0.07 to −0.68), but the CRP in PUFAs group was not significantly lower than vitamin E, PUFAs plus vitamin E, or medium-chain triglyceride. Although no significant changes were noted for hs-CRP and IL-6 levels, PUFAs showed the best ranking among treatments according to surface under the cumulative ranking. Therefore, PUFAs could be a protective option for patients receiving dialysis in clinical practice.

The Effects of OMEGA-3 Fatty Acid Supplementation Upon Interleukin-12 and Interleukin-18 in Chronic Kidney Disease Patients

OBJECTIVE(S)

Cardiovascular disease (CVD) remains a leading cause of mortality in chronic kidney disease (CKD) patients. Interventions targeting traditional risk factors have largely proven ineffective in CKD patients in part because of the increased role of nontraditional risk factors such as chronic inflammation. Omega-3 fatty acids (ω3FA) are inexpensive and safe natural agents, which target inflammation and have potential cardioprotective benefits. The aim of the study was to determine the effects of ω3FA supplementation upon serum interleukin (IL)-12, IL-18, and highly sensitive C-reactive protein (hsCRP) in patients with Stage 3-4 CKD.

METHODS

We performed a post-hoc analysis of a randomized placebo-controlled trial in 73 nondiabetic CKD patients to determine the effects of ω3FA supplementation (4 g daily for 8 weeks) upon serum levels of IL-12, IL-18, and hsCRP.

RESULTS

There were no preintervention differences in IL-12, IL-18, or hsCRP between treatment groups. Postintervention levels of IL-12, IL-18, and hsCRP were similar between the treatment groups. However, IL-12 and IL-18 increased in both treatment groups over the intervention period, whereas hsCRP remained unchanged. The magnitude of increase in serum IL-18 (ΔIL-18) was significantly less in participants in the ω3FA treatment group compared to placebo (P = .047).

CONCLUSION(S)

This study has shown that 4 g daily ω3FA supplementation may lower serum IL-18 levels in patients with moderate CKD. Although there were no apparent effects on several other markers of inflammation, this study provides evidence for a specific effect of ω3FA on inflammatory pathways.

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.

Stirring the Pot: Can Dietary Modification Alleviate the Burden of CKD?

Diet is one of the largest modifiable risk factors for chronic kidney disease (CKD)-related death and disability. CKD is largely a progressive disease; however, it is increasingly appreciated that hallmarks of chronic kidney disease such as albuminuria can regress over time. The factors driving albuminuria resolution remain elusive. Since albuminuria is a strong risk factor for GFR loss, modifiable lifestyle factors that lead to an improvement in albuminuria would likely reduce the burden of CKD in high-risk individuals, such as patients with diabetes. Dietary therapy such as protein and sodium restriction has historically been used in the management of CKD. Evidence is emerging to indicate that other nutrients may influence kidney health, either through metabolic or haemodynamic pathways or via the modification of gut homeostasis. This review focuses on the role of diet in the pathogenesis and progression of CKD and discusses the latest findings related to the mechanisms of diet-induced kidney disease. It is possible that optimizing diet quality or restricting dietary intake could be harnessed as an adjunct therapy for CKD prevention or progression in susceptible individuals, thereby reducing the burden of CKD.

Interventions for lowering plasma homocysteine levels in dialysis patients

BACKGROUND

People with end-stage kidney disease (ESKD) have high rates of cardiovascular events. Randomised controlled trials (RCTs) of homocysteine-lowering therapies have not shown reductions in cardiovascular event rates in the general population. However, people with kidney disease have higher levels of homocysteine and may have different mechanisms of cardiovascular disease. We performed a systematic review of the effect of homocysteine-lowering therapies in people with ESKD.

OBJECTIVES

To evaluate the benefits and harms of established homocysteine lowering therapy (folic acid, vitamin B6, vitamin B12) on all-cause mortality and cardiovascular event rates in patients with ESKD.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 25 January 2016 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Studies conducted in people with ESKD that reported at least 100 patient-years of follow-up and assessed the effect of therapies that are known to have homocysteine-lowering properties were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data using a standardised form. The primary outcome was cardiovascular mortality. Secondary outcomes included all-cause mortality, incident cardiovascular disease (fatal and nonfatal myocardial infarction and coronary revascularisation), cerebrovascular disease (stroke and cerebrovascular revascularisation), peripheral vascular disease (lower limb amputation), venous thromboembolic disease (deep vein thrombosis and pulmonary embolism), thrombosis of dialysis access, and adverse events. The effects of homocysteine-lowering therapies on outcomes were assessed with meta-analyses using random-effects models. Prespecified subgroup and sensitivity analyses were conducted.

MAIN RESULTS

We included six studies that reported data on 2452 participants with ESKD. Interventions investigated were folic acid with or without other vitamins (vitamin B6, vitamin B12). Participants' mean age was 48 to 65 years, and proportions of male participants ranged from 50% to 98%.Homocysteine-lowering therapy probably leads to little or no effect on cardiovascular mortality (4 studies, 1186 participants: RR 0.93, 95% CI 0.70 to 1.22). There was no evidence of heterogeneity among the included studies (I² = 0%). Homocysteine-lowering therapy had little or no effect on all-cause mortality or any other of this review's secondary outcomes. All prespecified subgroup and sensitivity analyses demonstrated little or no difference. Reported adverse events were mild and there was no increase in the incidence of adverse events from homocysteine-lowering therapies (3 studies, 1248 participants: RR 1.12, 95% CI 0.51 to 2.47; I(2) = 0%). Overall, studies were assessed as being at low risk of bias and there was no evidence of publication bias.

AUTHORS' CONCLUSIONS

Homocysteine-lowering therapies were not found to reduce mortality (cardiovascular and all-cause) or cardiovascular events among people with ESKD.

Effect of the omega-3 fatty acid plus vitamin E supplementation on subjective global assessment score, glucose metabolism, and lipid concentrations in chronic hemodialysis patients

SCOPE

This study was conducted to determine the effects of omega-3 fatty acid plus vitamin E supplementation on subjective global assessment (SGA) score and metabolic profiles in chronic hemodialysis (HD) patients.

METHODS AND RESULTS

This randomized double-blind placebo-controlled clinical trial was conducted among 120 chronic HD patients. Participants were randomly divided into four groups to receive: (i) 1250 mg/day omega-3 fatty acid containing 600 mg eicosapentaenoic acid and 300 mg docosahexaenoic acid + vitamin E placebo (n = 30), (ii) 400 IU/day vitamin E + omega-3 fatty acids placebo (n = 30), (iii) 1250 mg omega-3 fatty acids/day + 400 IU/day vitamin E (n = 30), and (iv) omega-3 fatty acids placebo + vitamin E placebo (n = 30) for 12 wk. Fasting blood samples were taken at baseline and after 12-wk intervention to measure metabolic profiles. Patients who received combined omega-3 fatty acids and vitamin E supplements compared with vitamin E, omega-3 fatty acids, and placebo had significantly decreased SGA score (p < 0.001), fasting plasma glucose (p = 0.01), serum insulin levels (p = 0.001), homeostasis model of assessment insulin resistance (p = 0.002), and improved quantitative insulin sensitivity check index (p = 0.006).

CONCLUSION

Omega-3 fatty acids plus vitamin E supplementation for 12 wk among HD patients had beneficial effects on SGA score and metabolic profiles.

Mitochondria: a new therapeutic target in chronic kidney disease

Cellular metabolic changes during chronic kidney disease (CKD) may induce higher production of oxygen radicals that play a significant role in the progression of renal damage and in the onset of important comorbidities. This condition seems to be in part related to dysfunctional mitochondria that cause an increased electron "leakage" from the respiratory chain during oxidative phosphorylation with a consequent generation of reactive oxygen species (ROS). ROS are highly active molecules that may oxidize proteins, lipids and nucleic acids with a consequent damage of cells and tissues. To mitigate this mitochondria-related functional impairment, a variety of agents (including endogenous and food derived antioxidants, natural plants extracts, mitochondria-targeted molecules) combined with conventional therapies could be employed. However, although the anti-oxidant properties of these substances are well known, their use in clinical practice has been only partially investigated. Additionally, for their correct utilization is extremely important to understand their effects, to identify the correct target of intervention and to minimize adverse effects. Therefore, in this manuscript, we reviewed the characteristics of the available mitochondria-targeted anti-oxidant compounds that could be employed routinely in our nephrology, internal medicine and renal transplant centers. Nevertheless, large clinical trials are needed to provide more definitive information about their use and to assess their overall efficacy or toxicity.

The effect of omega-3 on serum lipid profile in hemodialysis patients

Introduction: One of the major complications in hemodialysis patients is cardiovascular disease. Lipid abnormality is an important factor in the development of cardiovascular disease.

Objectives: To investigate the effect of omega-3 supplementation on serum lipid profile in hemodialysis patients.

Patients and Methods: This randomized clinical trial study included 2 groups of patients: those who received omega-3 supplementation (experimental group; 30 cases) and those who received placebo (control group; 30 cases). They received these for 10 weeks and serum lipid profile (triglyceride, high-density lipoprotein [HDL-C], low-density lipoprotein [LDL-C], and total cholesterol) was assessed 2 times, first before initiating supplementation and then at the end of 10-week study period.

Results: Mean (±SD) serum total cholesterol levels at the beginning was 163 (±47) mg/dL in experimental group and 143 (±25) mg/dL in control group (P> 0.05). These values decreased to 124 mg/dL and 132 mg/dL in control and experimental groups (P< 0.05). There was no significant difference of HDL-C, LDL-C, or triglyceride levels between experimental and control groups after 10 weeks of treatment.

Conclusion: Omega-3 supplementation in hemodialysis patients only showed significant decrease of serum total cholesterol level, but not other lipids.

Effects of fish oil on serum lipid profile in dialysis patients: a systematic review and meta-analysis of randomized controlled trials

Background

The effects of fish oil supplements on lipid profile in dialysis patients are controversial. With increasing interest in the potential health benefits of fish oil, it is important to explore its real effects.

Objective

We aimed to identify and quantify the effects of fish oil on triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in dialysis patients.

Methods

PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for relevant trials of fish oil and lipid profile in dialysis patients. We identified 209 potential studies and included 13 randomized controlled trials. Eligible studies, determined by consensus using predefined criteria, were reviewed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and a meta-analysis was performed.

Results

Compared with the control group, serum TG and TC levels in the fish oil group were reduced by 0.23 mmol/L (95% CI, −0.31, −0.14, P <0.01) and 0.12 mmol/L (95% CI, −0.23, −0.01, P =0.03), respectively. HDL-C levels were increased by 0.20 mmol/L (95% CI, 0.01, 0.40, P <0.01) attributable to fish oil. In contrast, fish oil did not influence serum LDL-C levels. Subgroup analysis showed the effects of fish oil were stronger in subjects with higher baseline TG levels, and the long-term intervention (>12w) demonstrated a tendency towards greater improvement of serum HDL-C and LDL-C levels compared with short-term intervention (≤12 w). However, both of the changes were not statistically significant in meta-regression analysis. There were no obvious difference in effects of different doses and components of fish oil on lipid levels.

Conclusion

Fish oil supplements reduced serum TG and TC levels, and increased HDL-C levels, without affecting LDL-C levels among dialysis patients. It should benefit patients at risk of cardiovascular diseases. Based on randomized controlled trials, we suggested a daily supplement dose of fish oil for dialysis patients of >1 g, but a high dose might not be necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-127) contains supplementary material, which is available to authorized users.

Potential effects of omega-3 fatty acids on anemia and inflammatory markers in maintenance hemodialysis patients

BACKGROUND

Anemia is a common complication among hemodialysis (HD) patients. Although intravenous iron and erythropoiesis-stimulating agents revolutionized anemia treatment, about 10% of HD patients show suboptimal response to these agents. Systemic inflammation and increased serum hepcidin level may contribute to this hyporesponsiveness. Considering the anti-inflammatory properties of omega-3 fatty acids, this study aimed to evaluate potential role of these fatty acids in improving anemia and inflammation of chronic HD patients.

METHODS

In this randomized, placebo-controlled trial, 54 adult patients with HD duration of at least 3 months were randomized to ingest 1800 mg of either omega-3 fatty acids or matching placebo per day for 4 months. Anemia parameters including blood hemoglobin, serum iron, transferrin saturation (TSAT), erythropoietin resistance index, and required dose of intravenous iron and erythropoietin, and serum concentrations of inflammatory/anti-inflammatory markers including interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, C-reactive protein (CRP), hepcidin, ferritin, intact parathyroid hormone (iPTH), and ratios of IL-10 to IL-6 and IL-10 to TNF-α were measured at baseline and after 4 months of the intervention.

RESULTS

45 subjects (25 in the omega-3 and 20 in the placebo group) completed the study. No significant changes were observed in blood hemoglobin, serum iron, TSAT, and required dose of intravenous iron in either within or between group comparisons. Additionally, erythropoietin resistance index as well as required dose of intravenous erythropoietin showed no significant change in the omega-3 group compared to the placebo group. Although a relative alleviation in inflammatory state appeared in the omega-3 group, the mean differences of inflammatory and anti-inflammatory markers between the two groups did not reach statistically significant level except for IL-10-to-IL-6 ratio and serum ferritin level which showed significant changes in favor of omega-3 treatment (P <0.001 and P = 0.003, respectively).

CONCLUSION

Omega-3 fatty acids relatively improved systemic inflammation of chronic HD patients without any prominent benefits on anemia. However, future well-designed studies on larger number of patients may determine utility of omega-3 fatty acids in HD patients with respect to inflammation and anemia.

Effects of protein and omega-3 supplementation, provided during regular dialysis sessions, on nutritional and inflammatory indices in hemodialysis patients

Purpose

Malnutrition and chronic inflammation in dialysis patients negatively impacts prognosis. However, intervening to correct this problem (through nutritional supplementation) is often hampered by poor compliance due to both medical and socioeconomic barriers. We have therefore performed a pilot study to investigate the technical feasibility of “directly observed treatment” of nutritional supplementation (protein and omega-3 fatty acids), administered during regular dialysis sessions. Secondary end points included observation of nutritional and inflammatory status of hypoalbuminemic patients undergoing hemodialysis.

Methods

Main inclusion criteria were serum albumin ≤ 3.9 g/dL (3 months prior to the study). Sixty-three eligible patients agreed to participate. Two intervention groups received 30 mL of a liquid protein supplement plus either 2.4 g omega-3 (1800 mg eicosapentaenoic acid + 600 mg docosahexaenoic acid) or a placebo, three times per week after their routine dialysis session for 6 months. Serum albumin, plasma lipids, and other indicators of nutritional and inflammatory status were measured.

Results

Directly observed nutritional supplementation resulted in a significant improvement in the low density lipoprotein cholesterol/high density lipoprotein cholesterol ratio in the omega-3 group as compared to the placebo group (P = 0.043). For the omega-3 group, serum albumin was also marginally higher after 6 months as compared to baseline (P = 0.07). The observed increase in C-reactive protein in the placebo group over 6 months was not apparent in the omega-3 group, although there was no significant difference between groups. Nuclear factor kappa B, malnutrition-inflammation score, normalized protein nitrogen appearance, body mass index, and hemoglobin were unaffected by the intervention.

Conclusion

“Directly observed treatment” with an omega-3 based supplement (as opposed to a pure protein supplement) showed beneficial effects on the lipid profile, and C-reactive protein levels. Further studies using a combination of outpatient and inpatient “directly observed treatment” of omega-3 based supplementation is warranted.