Association of red blood cell n-3 polyunsaturated fatty acids with plasma inflammatory biomarkers among the Quebec Cree population

A comprehensive exploration of chronic kidney disease and dialysis in Canada's Indigenous population: from epidemiology to genetic influences

PURPOSE

This study aims to review the escalating prevalence of chronic kidney disease (CKD) and end-stage renal disease (ESRD) among Canada's Indigenous population, focusing on risk factors, hospitalization and mortality rates, and disparities in kidney transplantation. The study explores how these factors contribute to the health outcomes of this population and examines the influence of genetic variations on CKD progression.

METHODS

The review synthesizes data on prevalence rates, hospitalization and mortality statistics, and transplantation disparities among Indigenous individuals. It also delves into the complexities of healthcare access, including geographical, socioeconomic, and psychological barriers. Additionally, the manuscript investigates the impact of racial factors on blood characteristics relevant to dialysis treatment and the genetic predispositions influencing disease progression in Indigenous populations.

RESULTS

Indigenous individuals exhibit a higher prevalence of CKD and ESRD risk factors such as diabetes and obesity, particularly in regions like Saskatchewan. These patients face a 77% higher risk of death compared to their non-Indigenous counterparts and are less likely to receive kidney transplants. Genetic analyses reveal significant associations between CKD and specific genomic variations. Through analyses, we found that healthy Indigenous individuals may have higher levels of circulating inflammatory markers, which could become further elevated for those with CKD. In particular, they may have higher levels of C-reactive protein (CRP) fibrinogen, as well as genomic variations that affect IL-6 production and the function of von Willebrand Factor (vWF) which has critical potential influence on the compatibility with dialysis membranes contributing to complications in dialysis.

CONCLUSION

Indigenous people in Canada are disproportionately burdened by CKD and ESRD due to socioeconomic factors and potential genetic predispositions. While significant efforts have been made to assess the socioeconomic conditions of the Indigenous population, the genetic factors and their potential critical influence on compatibility with dialysis membranes, contributing to treatment complications, remain understudied. Further investigation into these genetic predispositions is essential.

Measurement of diet quality among First Nations peoples in Canada and associations with health: a scoping review

BACKGROUND

Given the increasing number and the diversity of dietary quality indices used for research, and the differences between settings, there is a need to identify valid indices of dietary quality in different contexts and populations and to identify their associations with health-related outcomes.

OBJECTIVES

The primary objective of this scoping review is to identify the tools used in determining dietary quality among First Nations and to describe the changes in diet. The second objective is to describe the associations identified in studies that have measured the relationship between health and dietary quality among First Nations; and the third objective is to identify factors associated with diet quality.

METHODS

PubMed, Embase, CINAHL, Global Health, and Web of Science were searched from inception to June 2021 and updated in February 2022. Articles were included if the research subjects were First Nations, or if articles reported disaggregated subset data for First Nations. Eligible studies focused on nutrition and diet and were published in English or French.

RESULTS

A total of 151 articles were included in the analysis. Studies used several indicators to measure if individuals adhered to dietary guidelines. Traditional food consumption was frequently used as an indicator of diet quality (n = 96). The consumption of store-bought foods was used as an indicator in 28 studies. Some studies used other diet quality indicators such as the Healthy Eating Index (n = 5) and ultra-processed food "NOVA" classification (n = 6). A trend for decreasing traditional food intake over time was apparent, alongside an increase in store-bought food intake. This trend was accompanied with declining health status, including the increased prevalence of overweight and obesity, diabetes, metabolic diseases, and dental caries.

CONCLUSION

This scoping review showed that diet quality among First Nations is improved when traditional foods are consumed. Reduced diet quality was associated with increased risk of noncommunicable diseases.

Role of long-chain polyunsaturated fatty acids, eicosapentaenoic and docosahexaenoic, in the regulation of gene expression during the development of obesity: a systematic review

Introduction

There exists a correlation between obesity and the consumption of an excessive amount of calories, with a particular association between the intake of saturated and trans fats and an elevated body mass index. Omega-3 fatty acids, specifically eicosapentaenoic and docosahexaenoic acids, have been identified as potential preventive nutrients against the cardiometabolic hazards that are commonly associated with obesity. The objective of this comprehensive review was to elucidate the involvement of long-chain polyunsaturated fatty acids, specifically eicosapentaenoic acid and docosahexaenoic acid, in the modulation of gene expression during the progression of obesity.

Methods

The present analysis focused on primary studies that investigated the association between long-chain polyunsaturated fatty acids, gene expression, and obesity in individuals aged 18 to 65 years. Furthermore, a comprehensive search was conducted on many databases until August 2023 to identify English-language scholarly articles utilizing MeSH terms and textual content pertaining to long-chain polyunsaturated fatty acids, gene expression, obesity, and omega-3. The protocol has been registered on PROSPERO under the registration number CRD42022298395. A comprehensive analysis was conducted on a total of nine primary research articles. All research collected and presented quantitative data.

Results and Discussion

The findings of our study indicate that the incorporation of eicosapentaenoic and docosahexaenoic acid may have potential advantages and efficacy in addressing noncommunicable diseases, including obesity. This can be attributed to their anti-inflammatory properties and their ability to regulate genes associated with obesity, such as PPARγ and those within the ALOX family.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022298395, CRD42022298395.

Fatty Acids, Amphiregulin Production, and Lung Function in a Cohort of Midwestern Veterans

Rationale

The relationship between many fatty acids and respiratory outcomes remains unclear, especially with regard to mechanistic actions. Altered regulation of the process of lung repair is a key feature of chronic lung disease and may impact the potential for pulmonary rehabilitation, but underlying mechanisms of lung repair following injury or inflammation are not well-studied. The epidermal growth factor receptor agonist amphiregulin (AREG) has been demonstrated to promote lung repair following occupational dust exposure in animals. Studies suggest the polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) may enhance the production of AREG. The objective of this study was to determine the relationship between fatty acids and lung function in a population of veterans and determine if fatty acid status is associated with concentrations of AREG.

Materials and Methods

Data were collected from a cross-sectional study of veterans within the Nebraska-Western Iowa Health Care System. Whole blood assays were performed to quantify AREG concentrations via a commercially available ELISA kit. Fatty acids from plasma samples from the same patients were measured using gas-liquid chromatography. Intakes of fatty acids were quantified with a validated food frequency questionnaire. Linear regression models were used to determine whether plasma fatty acids or intakes of fatty acids predicted lung function or AREG concentrations. A p < 0.05 was considered statistically significant.

Results

Ninety participants were included in this analysis. In fully adjusted models, plasma fatty acids were associated with AREG production, including the PUFA eicosapentaenoic acid (EPA) (β = 0.33, p = 0.03) and the monounsaturated fatty acid octadecenoic acid: (β = −0.56, p = 0.02). The omega-3 PUFA docosapentaenoic acid (DPA) was positively associated with lung function (β = 0.28, p = 0.01; β = 26.5, p = 0.05 for FEV₁/FVC ratio and FEV₁ % predicted, respectively), as were the omega-6 PUFAs eicosadienoic acid (β = 1.13, p < 0.001; β = 91.2, p = 0.005 for FEV₁/FVC ratio and FEV₁ % predicted, respectively) and docosadienoic acid (β = 0.29, p = 0.01 for FEV₁/FVC ratio). Plasma monounsaturated and saturated fatty acids were inversely associated with lung function.

Conclusion

Opposing anti- and pro-inflammatory properties of different fatty acids may be associated with lung function in this population, in part by regulating AREG induction.

ω-3 DPA Protected Neurons from Neuroinflammation by Balancing Microglia M1/M2 Polarizations through Inhibiting NF-κB/MAPK p38 Signaling and Activating Neuron-BDNF-PI3K/AKT Pathways

Microglia M1 phenotype causes HPA axis hyperactivity, neurotransmitter dysfunction, and production of proinflammatory mediators and oxidants, which may contribute to the etiology of depression and neurodegenerative diseases. Eicosapentaenoic acid (EPA) may counteract neuroinflammation by increasing n-3 docosapentaenoic acid (DPA). However, the cellular and molecular mechanisms of DPA, as well as whether it can exert antineuroinflammatory and neuroprotective effects, are unknown. The present study first evaluated DPA’s antineuroinflammatory effects in lipopolysaccharide (LPS)-activated BV2 microglia. The results showed that 50 μM DPA significantly decreased BV2 cell viability after 100 ng/mL LPS stimulation, which was associated with significant downregulation of microglia M1 phenotype markers and proinflammatory cytokines but upregulation of M2 markers and anti-inflammatory cytokine. Then, DPA inhibited the activation of mitogen-activated protein kinase (MAPK) p38 and nuclear factor-κB (NF-κB) p65 pathways, which results were similar to the effects of NF-κB inhibitor, a positive control. Second, BV2 cell supernatant was cultured with differentiated SH-SY5Y neurons. The results showed that the supernatant from LPS-activated BV2 cells significantly decreased SH-SY5Y cell viability and brain-derived neurotrophic factor (BDNF), TrkB, p-AKT, and PI3K expression, which were significantly reversed by DPA pretreatment. Furthermore, DPA neuroprotection was abrogated by BDNF-SiRNA. Therefore, n-3 DPA may protect neurons from neuroinflammation-induced damage by balancing microglia M1 and M2 polarizations, inhibiting microglia-NF-κB and MAPK p38 while activating neuron-BDNF/TrkB-PI3K/AKT pathways.

Effectiveness of a combined New Zealand green-lipped mussel and Antarctic krill oil supplement on markers of exercise-induced muscle damage and inflammation in untrained men

Green-lipped mussel oil (PCSO-524^®) has been shown to attenuate signs and symptoms of exercise-induced muscle damage (EIMD), and krill oil has been shown to have a protective effect against cytokine-induced tissue degradation. The purpose of this study was to compare the effects of PCSO-524^® and ESPO-572^® (75% PCSO-524^® and 25% krill oil) on signs and symptoms of EIMD. Fifty-one untrained men consumed 600 mg/d of PCSO-524^® (n = 24) or ESPO-572^® (n = 27) for 26 d prior to and 72 h following a downhill running bout. Delayed onset muscle soreness (DOMS), pressure pain threshold, limb swelling, range of motion (ROM), isometric torque, and blood markers of inflammation and muscle damage were assessed at baseline, 24, 48 and 72 h post-eccentric exercise. ESPO-572^® was 'at least as good as' PCSO-524^® and both blends were superior (p < 0.05) to placebo in lessening the increase in DOMS at 24, 48, 72 h. ESPO-572^® and PCSO-524^® were protective against joint ROM loss compared to placebo (p < 0.05) at 48 and 72 h. Notably, at 24 and 48 h, joint ROM was higher in the ESPO-572^® compared to the PCSO-524^® group (p < 0.05). No differences between the two blends for the other markers were found. ESPO-572^® is 'at least as good' as PCSO-524^® in reducing markers of muscle damage and soreness following eccentric exercise and was superior to PCSO-524^® in protecting against the loss in joint ROM during recovery. Our data support the use of ESPO-572^®, a combination of green-lipped mussel and krill oil, in mitigating the deleterious effects of EIMD.

Oral supplementation with omega-3 fatty acids and inflammation markers in patients with chronic kidney disease in hemodialysis

Chronic kidney disease (CKD) is an increasingly common public health problem that increases the risk of death because of cardiovascular complications by 2-3 times compared with the general population. This research concerns a prospective, randomized, double-blind study in patients with CKD undergoing hemodialysis. The participants were assigned to 1 of 2 groups: the study group (group A; 46 patients) received 4 capsules (2.4 g) of omega-3 fatty acids daily during the 12-week intervention, while patients in the control group (group B; 47 patients) received 4 capsules of paraffin oil. The patients' general characteristics, nutritional indicators, renal disease markers and inflammatory markers (C-reactive protein, interleukin (IL)-6, IL-10, and tumour necrosis factor alpha (TNF-α)) were evaluated. No differences were found between the general characteristics of the patients (P < 0.05), and no differences were shown in the nutritional indicators and markers of kidney disease (P < 0.05). Patients in group A showed significant decreases in levels of C-reactive protein, IL-6, TNF-α, and the IL-10/IL-6 ratio after 12 weeks of supplementation (P < 0.05). Patients in group B did not show any significant changes in concentrations of inflammatory markers during the intervention (P < 0.05). In conclusion, oral supplementation with omega-3 fatty acids produces a significant decrease in the concentrations of inflammation markers in patients with chronic kidney disease on hemodialysis. Novelty Oral supplementation with omega-3 fatty acids produced significant decreases in the concentrations of inflammation markers. This supplementation could be given to patients with uremic syndrome and coronary heart disease to reduce cardiovascular risk.

The effect of omega-3 and vitamin E on oxidative stress and inflammation: Systematic review and meta-analysis of randomized controlled trials

Background: Several studies have investigated the effect of omega-3 fatty acids and vitamin E on oxidative stress and inflammation, but their findings are inconsistent. The aim of this meta-analysis is to elucidate the overall effects of co-supplementation with omega-3 fatty acids and vitamin E on oxidative stress and inflammation. Methods: We searched titles, abstracts, and keywords of relevant articles indexed in PubMed, ISI, Scopus, and Google Scholar databases up to December 2018 to identify eligible RCT studies. Random effects model was used to estimate the pooled effect of co-supplementation with omega-3 fatty acids and vitamin E on oxidative stress and inflammation. Results: Overall, 7 RCTs with 504 participants were included in this meta-analysis. We found that co-supplementation with omega-3 fatty acids and vitamin E decreased hs-CRP (weighed mean difference (WMD) = -2.15 mg/L; 95% CI: -3.40, -0.91 mg/L; P < 0.001) concentrations and increased total antioxidant capacity (TAC) (WMD = 92.87 mmol/L; 95% CI: 31.97, 153.77 mmol/L; P = 0.03), and nitric oxide levels (NO) (WMD: 6.95 μmol/L; 95% CI: 3.86, 10.04, P < 0.001) compared with control group. Omega-3 fatty acids and vitamin E had no significant effect on malondialdehyde (MDA) (WMD: 1.54 mmol/L; 95% CI: -1.29, 4.36; P = 0.196), and glutathione (GSH) (WMD: 20.87 mmol/L; 95% CI: -20.04, 61.6, P = 0.31) levels. Conclusion: The present meta-analysis found that omega-3 fatty acids and vitamin E co-supplementation significantly decreased hs-CRP and increased NO and TAC, although it had no significant effect on MDA and GSH.

Plasma Levels of Marine n-3 Fatty Acids Are Inversely Correlated With Proinflammatory Markers sTNFR1 and IL-6 in Renal Transplant Recipients

OBJECTIVE

Marine n-3 polyunsaturated fatty acids (PUFAs) exert potential anti-inflammatory effects and might improve long-term outcomes after renal transplantation. We assessed associations between plasma phospholipid levels of marine n-3 PUFAs and plasma inflammatory biomarkers 10 weeks after renal transplantation.

DESIGN

Cross-sectional single-center study.

SUBJECTS

A study population of 861 renal transplant recipients transplanted at Oslo University Hospital between 2007 and 2011.

METHODS AND MAIN OUTCOME MEASURE

Plasma phospholipid fatty acids were determined by gas chromatography. Marine n-3 PUFA levels were defined as the sum of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid levels in weight percentage of total plasma phospholipid fatty acids. Plasma inflammatory biomarkers were measured by enzyme immunoassays. We used multivariable linear regression analysis to assess associations between levels of marine n-3 PUFAs and inflammatory biomarkers in plasma.

RESULTS

Plasma marine n-3 PUFA levels were inversely associated with plasma levels of proinflammatory biomarkers soluble tumor necrosis factor receptor 1 (standardized regression coefficient -0.11, P < .001) and interleukin-6 (standardized regression coefficient -0.09, P = .01). In contrast, there was no association between plasma levels of marine n-3 PUFAs and the anti-inflammatory mediator interleukin-10.

CONCLUSIONS

In this renal transplant cohort, inverse associations between plasma levels of marine n-3 PUFAs and markers of inflammation were demonstrated.

Short update on docosapentaenoic acid: a bioactive long-chain n-3 fatty acid

PURPOSE OF REVIEW

Docosapentaenoic acid (DPA) is a long-chain n-3 polyunsaturated fatty acid that is intermediary between eicosapentaenoic acid and docosahexaenoic acid in the n-3 synthesis pathway. DPA is part of our normal diet through fish and lean red meat. In recent years, DPA has received increasing attention as an important bioactive fatty acid in light of its potential beneficial health effects, which include anti-inflammatory actions, antiplatelet aggregation, and improved plasma lipid prolife. This review provides a short summary of the most recent research on DPA.

RECENT FINDINGS

In this review, we report on the latest association data as well as data generated from in-vitro and in-vivo studies on DPA and cardiovascular health, mental health, inflammation, and cancer. We also report on the newly identified DPA metabolites and their effects on exacerbation of inflammation in animal models.

SUMMARY

Although there is a growing body of evidence supporting DPA's role as an important bioactive fatty acid, there is a need for more 'cause and effect studies', clinical trials and studies which can reveal whether DPA plays separate roles to those identified for eicosapentaenoic acid and docosahexaenoic acid.

Red Blood Cell Docosapentaenoic Acid (DPA n-3) is Inversely Associated with Triglycerides and C-reactive Protein (CRP) in Healthy Adults and Dose-Dependently Increases Following n-3 Fatty Acid Supplementation

The role of the long-chain omega-3 (n-3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in lipid metabolism and inflammation has been extensively studied; however, little is known about the relationship between docosapentaenoic acid (DPA, 22:5 n-3) and inflammation and triglycerides (TG). We evaluated whether n-3 DPA content of red blood cells (RBC) was associated with markers of inflammation (interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and C-reactive protein (CRP) and fasting TG prior to n-3 supplementation in two studies (Study 1: n = 115, aged 20-44 years, body mass index (BMI) 20-30 kg/m2, TG = 34-176 mg/dL; Study 2: n = 28, aged 22-65 years, BMI 24-37 kg/m2, TG = 141-339 mg/dL). We also characterized the dose-response effects of n-3 fatty acid supplementation on RBC n-3 DPA after five months of supplementation with fish oil (Study 1: 0, 300, 600, 900, and 1800 mg/day EPA + DHA) and eight weeks of prescription n-3 ethyl esters (Study 2: 0, 850, and 3400 mg/day EPA + DHA). In Study 1, RBC n-3 DPA was inversely correlated with CRP (R2 = 36%, p < 0.001) and with fasting TG (r = -0.30, p = 0.001). The latter finding was replicated in Study 2 (r = -0.33, p = 0.04). In both studies, n-3 supplementation significantly increased RBC n-3 DPA dose-dependently. Relative increases were greater for Study 1, with increases of 29%-61% vs. 14%-26% for Study 2. The associations between RBC n-3 DPA, CRP, and fasting TG may have important implications for the prevention of atherosclerosis and chronic inflammatory diseases and warrant further study.

Red blood cell fatty acids and biomarkers of inflammation: a cross-sectional study in a community-based cohort

INTRODUCTION

Inflammation and inflammatory biomarkers have emerged as integral components and predictors of incident cardiovascular (CV) disease. Omega-3 fatty acids, particularly eicosapentaenoic and docosahexaenoic acids (EPA and DHA) have anti-inflammatory properties, and have been variably associated with lower blood pressure, favorable blood lipid changes, and reduced CV events.

METHODS AND RESULTS

We examined the cross-sectional association of red blood cell (RBC) fatty acids, representative of body membrane fatty acid composition, with 10 biomarkers active in multiple inflammatory pathways in 2724 participants (mean age 66 ± 9 years, 54% women, 8% minorities) from the Framingham Offspring and minority Omni Cohorts. After multivariable adjustment, the RBC EPA and DHA content was inversely correlated (all P ≤ 0.001) with 8 biomarkers: urinary isoprostanes (r = -0.16); and soluble interleukin-6 (r = -0.10); C-reactive protein (r = -0.08); tumor necrosis factor receptor 2 (r = -0.08); intercellular adhesion molecule-1 (r = -0.08); P-selectin (r = -0.06); lipoprotein-associated phospholipase-A2 mass (r = -0.11) and activity (r = -0.08). The correlations for monocyte chemoattractant protein-1 was -0.05, P = 0.006 and osteoprotegerin (r = -0.06, P = 0.002) were only nominally significant.

CONCLUSION

In our large community-based study, we observed modest inverse associations between several types of inflammatory biomarkers with RBC omega-3 fatty acid levels. Our findings are consistent with the hypothesis that omega-3 fatty acids have anti-inflammatory properties.

Omega-3 and omega-6 Fatty acids in blood and breast tissue of high-risk women and association with atypical cytomorphology

The ratio of omega-3 to omega-6 fatty acids, especially the long-chain eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) to arachidonic acid (AA) ratio, is inversely associated with breast cancer risk. We measured the association between cytologic atypia, a biomarker for short-term risk of breast cancer development, and omega-3 and omega-6 fatty acid intake and levels in blood and breast tissue. Blood and benign breast tissue, sampled by random periareolar fine-needle aspiration (RPFNA), was obtained from 70 women at elevated risk for breast cancer. Self-reported dietary intake was assessed by the NCI's Food Frequency Questionnaire. The fatty acid composition of five lipid compartments, red blood cell, plasma and breast phospholipids, and plasma and breast triaclyglycerides (TAG), was analyzed by gas chromatography as weight percent. Median daily intakes of EPA+DHA and total omega-3 fatty acids were 80 mg and 1.1 g, respectively. The median total omega-3:6 intake ratio was 1:10. Compared with women without atypia, those with cytologic atypia had lower total omega-3 fatty acids in red blood cell and plasma phospholipids and lower omega-3:6 ratios in plasma TAGs and breast TAGs (P < 0.05). The EPA+DHA:AA ratio in plasma TAGs was also lower among women with atypia. This is the first report of associations between tissue levels of omega-3 and omega-6 fatty acids and a reversible tissue biomarker of breast cancer risk. RPFNA cytomorphology could serve as a surrogate endpoint for breast cancer prevention trials of omega-3 fatty acid supplementation.

Effects of n-3 polyunsaturated fatty acids (ω-3) supplementation on some cardiovascular risk factors with a ketogenic Mediterranean diet

Background: the ketogenic diet (KD) has become a widely used nutritional approach for weight loss. Some of the KD’s positive effects on metabolism and cardiovascular risk factors are similar to those seen after n-3 polyunsaturated fatty acids (ω-3) supplementation. We hypothesized that a ketogenic Mediterranean diet with phytoextracts combined with ω-3 supplementation may have increased positive effects on cardiovascular risk factors and inflammation. Methods: We analyzed 34 male overweight subjects; aged between 25 and 65 years who were overall healthy apart from overweight. The subjects followed a ketogenic diet protocol for four weeks; with (KDO3) or without (KD) ω-3 supplementation. Results: All subjects experienced a significant loss of body weight and body fat and there was no significant differences between treatment (body weight: KD—4.7 kg, KDO3—4.03 kg, body fat KD—5.41 kg, KDO3—5.86 kg). There were also significant decreases in total cholesterol, LDL-c, and glucose levels. Triglycerides and insulin levels decreased more in KDO3 vs. KD subjects, with a significant difference. All the investigated inflammatory cytokines (IL-1β, IL-6, TNF-α) decreased significantly in KDO3 subjects whilst only TNF-α showed a significant decrease in KD subjects over the 12 month study period. No significant changes were observed in anti-inflammatory cytokines (IL-10 and IL-1Ra), creatinine, urea and uric acid. Adiponectin increased significantly only in the KDO3 group. Conclusions: ω-3 supplementation improved the positive effects of a ketogenic Mediterranean diet with phytoextracts on some cardiovascular/metabolic risk factors and inflammatory state.