Plasma incorporation, apparent retroconversion and β-oxidation of 13C-docosahexaenoic acid in the elderly

Genetic association between FADS and ELOVL polymorphisms and the circulating levels of EPA/DHA in humans: a scoping review

BACKGROUND

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two omega-3 fatty acids that can be synthesized out of their precursor alpha-linolenic acid (ALA). FADS and ELOVL genes encode the desaturase and elongase enzymes required for EPA and DHA synthesis from ALA; however, single nucleotide polymorphisms (SNPs) in FADS and ELOVL genes could modify the levels of EPA and DHA synthesized from ALA although there is no consensus in this area. This review aims to investigate EPA and DHA circulating levels in human blood and their association with FADS or ELOVL.

METHODS

PubMed, Cochrane, and Scopus databases were used to identify research articles. They were subsequently reviewed by two independent investigators.

RESULTS

Initially, 353 papers were identified. After removing duplicates and articles not meeting inclusion criteria, 98 full text papers were screened. Finally, this review included 40 studies investigating FADS and/or ELOVL polymorphisms. A total of 47 different SNPs in FADS genes were reported. FADS1 rs174537, rs174547, rs174556 and rs174561 were the most studied SNPs, with minor allele carriers having lower levels of EPA and DHA. SNPs in the FADS genes were in high linkage disequilibrium. SNPs in FADS were correlated with levels of EPA and DHA. No conclusion could be drawn with the ELOVL polymorphisms since the number of studies was too low.

CONCLUSION

Specific SNPs in FADS gene, such as rs174537, have strong associations with circulating levels of EPA and DHA. Continued investigation regarding the impact of genetic variants related to EPA and DHA synthesis is warranted.

A vegetable fat-based diet delays psychomotor and cognitive development compared with maternal dairy fat intake in infant gray mouse lemurs

Dairy fat has a unique lipid profile; it is rich in short- and medium-chain saturated fatty acids that induce ketone production and has a balanced ω6/ω3 ratio that promotes cognitive development in early life. Moreover, the high consumption of vegetable oils in pregnant and lactating women raises concerns regarding the quality of lipids provided to offspring. Here, we investigate maternal dairy fat intake during gestation and lactation in a highly valuable primate model for infant nutritional studies, the gray mouse lemur (Microcebus murinus). Two experimental diets are provided to gestant mouse lemurs: a dairy fat-based (DF) or vegetable fat-based diet (VF). The psychomotor performance of neonates is tested during their first 30 days. Across all tasks, we observe more successful neonates born to mothers fed a DF diet. A greater rate of falls is observed in 8-day-old VF neonates, which is associated with delayed psychomotor development. Our findings suggest the potential benefits of lipids originating from a lactovegetarian diet compared with those originating from a vegan diet for the psychomotor development of neonates.

Sex, Body Mass Index, and APOE4 Increase Plasma Phospholipid-Eicosapentaenoic Acid Response During an ω-3 Fatty Acid Supplementation: A Secondary Analysis

BACKGROUND

The brain is concentrated with omega (ω)-3 (n-3) fatty acids (FAs), and these FAs must come from the plasma pool. The 2 main ω-3 FAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), must be in the form of nonesterified fatty acid (NEFA) or esterified within phospholipids (PLs) to reach the brain. We hypothesized that the plasma concentrations of these ω-3 FAs can be modulated by sex, body mass index (BMI, kg/m2), age, and the presence of the apolipoprotein (APO) E-ε4 allele in response to the supplementation.

OBJECTIVES

This secondary analysis aimed to determine the concentration of EPA and DHA within plasma PL and in the NEFA form after an ω-3 FA or a placebo supplementation and to investigate whether the factors change the response to the supplement.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted. Participants were randomly assigned to either an ω-3 FA supplement (DHA 0.8 g and EPA 1.7 g daily) or to a placebo for 6 mo. FAs from fasting plasma samples were extracted and subsequently separated into PLs with esterified FAs and NEFAs using solid-phase extraction. DHA and EPA concentrations in plasma PLs and as NEFAs were quantified using gas chromatography.

RESULTS

EPA and DHA concentrations in the NEFA pool significantly increased by 31%-71% and 42%-82%, respectively, after 1 and 6 mo of ω-3 FA supplementation. No factors influenced plasma DHA and EPA responses in the NEFA pool. In the plasma PL pool, DHA increased by 83%-109% and EPA by 387%-463% after 1 and 6 mo of ω-3 FA supplementation. APOE4 carriers, females, and individuals with a BMI of ≤25 had higher EPA concentrations than noncarriers, males, and those with a BMI of >25, respectively.

CONCLUSIONS

The concentration of EPA in plasma PLs are modulated by APOE4, sex, and BMI. These factors should be considered when designing clinical trials involving ω-3 FA supplementation. This trial was registered at clinicaltrials.gov as NCT01625195.

Evidence on docosahexaenoic acid and arachidonic acid supplementation for preterm infants

PURPOSE OF REVIEW

For many decades, docosahexaenoic acid (DHA) supplementation was tested in premature infants to achieve an intake equivalent to the average level in breast milk, but this approach has led to conflicting results in terms of development and health outcomes. Higher doses of DHA closer to fetal accumulation may be needed.

RECENT FINDINGS

The efficacy of DHA supplementation for preterm infants at a dose equivalent to the estimated fetal accumulation rate is still under investigation, but this may be a promising approach, especially in conjunction with arachidonic acid supplementation. Current data suggest benefit for some outcomes, such as brain maturation, long-term cognitive function, and the prevention of retinopathy of prematurity. The possibility that supplementation with highly unsaturated oils increases the risk of neonatal morbidities should not be ruled out, but current meta-analyzes do not support a significant risk.

SUMMARY

The published literature supports a DHA intake in preterm infants that is closer to the fetal accumulation rate than the average breast milk content. Supplementation with DHA at this level in combination with arachidonic acid is currently being investigated and appears promising.

Synthesis and Preclinical Evaluation of 22-[18F]Fluorodocosahexaenoic Acid as a Positron Emission Tomography Probe for Monitoring Brain Docosahexaenoic Acid Uptake Kinetics

Docosahexaenoic acid [22:6(n-3), DHA], a polyunsaturated fatty acid, has an important role in regulating neuronal functions and in normal brain development. Dysregulated brain DHA uptake and metabolism are found in individuals carrying the APOE4 allele, which increases the genetic risk for Alzheimer's disease (AD), and are implicated in the progression of several neurodegenerative disorders. However, there are limited tools to assess brain DHA kinetics in vivo that can be translated to humans. Here, we report the synthesis of an ω-radiofluorinated PET probe of DHA, 22-[18F]fluorodocosahexaenoic acid (22-[18F]FDHA), for imaging the uptake of DHA into the brain. Using the nonradiolabeled 22-FDHA, we confirmed that fluorination of DHA at the ω-position does not significantly alter the anti-inflammatory effect of DHA in microglial cells. Through dynamic PET-MR studies using mice, we observed the accumulation of 22-[18F]FDHA in the brain over time and estimated DHA's incorporation coefficient (K*) using an image-derived input function. Finally, DHA brain K* was validated using intravenous administration of 15 mg/kg arecoline, a natural product known to increase the DHA K* in rodents. 22-[18F]FDHA is a promising PET probe that can reveal altered lipid metabolism in APOE4 carriers, AD, and other neurologic disorders. This new probe, once translated into humans, would enable noninvasive and longitudinal studies of brain DHA dynamics by guiding both pharmacological and nonpharmacological interventions for neurodegenerative diseases.

Associations of fatty acids composition and estimated desaturase activities in erythrocyte phospholipids with biochemical and clinical indicators of cardiometabolic risk in non-diabetic Serbian women: the role of level of adiposity

Introduction

Fatty acids (FAs) composition and desaturase activities can be altered in different metabolic conditions, but the adiposity-independent associations with clinical and biochemical indicators of cardiometabolic risk are still unclear. This study aimed to analyze the associations of FAs composition and estimated desaturase activities with anthropometric, clinical, and biochemical cardiometabolic risk indicators in non-diabetic Serbian women, and to investigate if these associations were independent of the level of adiposity and other confounders.

Methods

In 76 non-diabetic, otherwise healthy Serbian women, aged 24-68 years, with or without metabolic syndrome or obesity (BMI=23.6±5.6 kg/m2), FA composition in erythrocyte phospholipids was measured by gas-liquid chromatography. Desaturase activities were estimated from product/precursor FAs ratios (D9D:16:1n-7/16:0; D6D:20:3n-6/18:2n-6; D5D:20:4n-6/20:3n-6). Correlations were made with anthropometric, biochemical (serum glucose, triacylglycerols, LDL-C, HDL-C, ALT, AST, and their ratios) and clinical (blood pressure) indicators of cardiometabolic risk. Linear regression models were performed to test the independence of these associations.

Results

Estimated desaturase activities and certain FAs were associated with anthropometric, clinical and biochemical indicators of cardiometabolic risk: D9D, D6D, 16:1n-7 and 20:3n-6 were directly associated, while D5D and 18:0 were inversely associated. However, the associations with clinical and biochemical indicators were not independent of the associations with the level of adiposity, since they were lost after controlling for anthropometric indices. After controlling for multiple confounders (age, postmenopausal status, education, smoking, physical activity, dietary macronutrient intakes, use of supplements, alcohol consumption), the level of adiposity was the most significant predictor of desaturase activities and aforementioned FAs levels, and mediated their association with biochemical/clinical indicators. Vice versa, desaturase activities predicted the level of adiposity, but not other components of cardiometabolic risk (if the level of adiposity was accounted). While the associations of anthropometric indices with 16:1n-7, 20:3n-6, 18:0 and D9D and D6D activities were linear, the associations with D5D activity were the inverse U-shaped. The only adiposity-independent association of FAs profiles with the indicators of cardiometabolic risk was a positive association of 20:5n-3 with ALT/AST ratio, which requires further exploration.

Discussion

Additional studies are needed to explore the mechanisms of the observed associations.

Quantitative Lipidomic Analysis of Serum Phospholipids Reveals Dissociable Markers of Alzheimer's Disease and Subcortical Cerebrovascular Disease

BACKGROUND

Circulating phospholipid species have been shown to predict Alzheimer's disease (AD) prognosis but the link between phospholipid disturbances and subcortical small vessel cerebrovascular disease (CeVD) common in AD patients is not known.

OBJECTIVE

This study used quantitative lipidomics to measure serum diacyl, alkenyl (ether), alkyl, and lyso phospholipid species in individuals with extensive CeVD (n = 29), AD with minimal CeVD (n = 16), and AD with extensive CeVD (n = 14), and compared them to age-matched controls (n = 27). Memory was assessed using the California Verbal Learning Test. 3.0T MRI was used to assess hippocampal volume, atrophy, and white matter hyperintensity (WMH) volumes as manifestations of CeVD.

RESULTS

AD was associated with significantly higher concentrations of choline plasmalogen 18:0_18:1 and alkyl-phosphocholine 18:1. CeVD was associated with significantly lower lysophospholipids containing 16:0. Phospholipids containing arachidonic acid (AA) were associated with poorer memory in controls, whereas docosahexaenoic acid (DHA)-containing phospholipids were associated with better memory in individuals with AD+CeVD. In controls, DHA-containing phospholipids were associated with more atrophy and phospholipids containing linoleic acid and AA were associated with less atrophy. Lysophospholipids containing 16:0, 18:0, and 18:1 were correlated with less atrophy in controls, and of these, alkyl-phosphocholine 18:1 was correlated with smaller WMH volumes. Conversely, 16:0_18:1 choline plasmalogen was correlated with greater WMH volumes in controls.

CONCLUSION

This study demonstrates discernable differences in circulating phospholipids in individuals with AD and CeVD, as well as new associations between phospholipid species with memory and brain structure that were specific to contexts of commonly comorbid vascular and neurodegenerative pathologies.

New perspectives on randomized controlled trials with omega-3 fatty acid supplements and cognition: A scoping review

Long chain polyunsaturated omega-3 fatty acids (n-3 FA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known to be important components in a healthy diet and contribute to healthy functioning of the heart and the brain, among other organs. Although there are epidemiological studies on the strong relationship between fish or n-3 FA consumption and lower risk of cognitive decline, results from randomized controlled trials (RCTs) are less consistent. Here, we performed a scoping review on RCTs with n-3 FA supplementation where cognition was evaluated. Seventy-eight RCTs published before April 2022 were included in this review. Among these RCTs, 43.6% reported a positive cognitive outcome after the consumption of n-3 FA compared to the placebo. However, there was a large diversity of populations studied (age ranges and health status), wide range of doses of EPA + DHA supplemented (79 mg/day - 5200 mg/day) and a multitude of tests evaluating cognition, mainly diagnostic tests, that were used to assess cognitive scores and overall cognitive status. RCTs were thereafter categorized into non-cognitively impaired middle-aged adults (n = 24), non-cognitively impaired older adults (n = 24), adults with subjective memory complaints (n = 14), adults with mild cognitive impairments (MCI, n = 9) and people with diagnosed dementia or other cognitive changes (n = 7). Among these categories, 66.7% of RCTs conducted with MCI adults reported a positive cognitive outcome when supplemented with n-3 FA vs. the placebo. Therefore, this scoping review provides rationale and questions to a) strengthen the design of future RCTs with n-3 FA for cognitive outcomes, and b) generate more informative data to support clinicians in their practice in assessing cognition before and after a nutritional intervention.

The Influence of Family History of Type 2 Diabetes on Metabolism during Submaximal Aerobic Exercise and in the Recovery Period in Postmenopausal Women

Aging and family history of type 2 diabetes (T2D) are known risk factors of T2D. Younger first-degree relatives (FDR) of T2D patients have shown early metabolic alterations, which could limit exercise's ability to prevent T2D. Thus, the objective was to determine whether exercise metabolism was altered during submaximal exercise in FDR postmenopausal women. Nineteen inactive postmenopausal women (control: 10, FDR: 9) aged 60 to 75 years old underwent an incremental test on a cycle ergometer with intensity ranging from 40 to 70% of peak power output. Participants consumed 50 mg of 13C-palmitate 2 h before the test. At the end of each stage, glucose, lactate, glycerol, non-esterified fatty acids and 13C-palmitate were measured in plasma, and 13CO2 was measured in breath samples. Gas exchanges and heart rate were both monitored continuously. There were no between-group differences in substrate oxidation, plasma substrate concentrations or 13C recovered in plasma or breath. Interestingly, despite exercising at a similar relative intensity to control, FDR were consistently at a lower percentage of heart rate reserve. Overall, substrate plasma concentration and oxidation are not affected by family history of T2D in postmenopausal women and therefore not a participating mechanism in the altered response to exercise previously reported. More studies are required to better understand the mechanisms involved in this response.

Estimation and predictors of the Omega-3 Index in the UK Biobank

Information on the Omega-3 Index (O3I) in the United Kingdom (UK) are scarce. The UK-Biobank (UKBB) contains data on total plasma omega-3 polyunsaturated fatty acids (n3-PUFA%) and DHA% measured by NMR. The aim of our study was to create an equation to estimate the O3I (eO3I) from these data. We first performed an interlaboratory experiment with 250 random blood samples in which the O3I was measured in erythrocytes by gas chromatography, and total n3% and DHA% were measured in plasma by NMR. The best predictor of eO3I included both DHA% and a derived metric, the total n3%-DHA%. Together these explained 65% of the variability (r=0.832, p<0.0001). We then estimated the O3I in 117,108 UKBB subjects and correlated it with demographic and lifestyle variables in multivariable adjusted models. The mean (SD) eO3I was 5.58% (2.35%) this UKBB cohort. Several predictors were significantly correlated with eO3I (all p<0.0001). In general order of impact and with directionality (- = inverse, + = direct): oily-fish consumption (+), fish oil supplement use (+), female sex (+), older age (+), alcohol use (+), smoking (-), higher waist circumference and BMI (-), lower socioeconomic status and less education (-). Only 20.5% of eO3I variability could be explained by predictors investigated, and oily-fish consumption accounted for 7.0% of that. With the availability of the eO3I in the UKBB cohort we will be in a position to link risk for a variety of diseases with this commonly-used and well-documented marker of n3-PUFA biostatus.

Accumulation of Arachidonic Acid, Precursor of Pro-Inflammatory Eicosanoids, in Adipose Tissue of Obese Women: Association with Breast Cancer Aggressiveness Indicators

While obesity is linked to cancer risk, no studies have explored the consequences of body mass index (BMI) on fatty acid profiles in breast adipose tissue and on breast tumor aggressiveness indicators. Because of this, 261 breast adipose tissue samples of women with invasive breast carcinoma were analyzed. Fatty acid profile was established by gas chromatography. For normal-weight women, major changes in fatty acid profile occurs after menopause, with the enrichment of long-chain polyunsaturated fatty acids (LC-PUFAs) of both n-6 and n-3 series enrichment, but a stable LC-PUFAs n-6/n-3 ratio across age. BMI impact was analyzed by age subgroups to overcome the age effect. BMI increase is associated with LC-PUFAs n-6 accumulation, including arachidonic acid. Positive correlations between BMI and several LC-PUFAs n-6 were observed, as well as a strong imbalance in the LC-PUFAs n-6/n-3 ratio. Regarding cancer, axillary lymph nodes (p = 0.02) and inflammatory breast cancer (p = 0.08) are more frequently involved in obese women. Increased BMI induces an LC-PUFAs n-6 accumulation, including arachidonic acid, in adipose tissue. This may participate in the development of low-grade inflammation in obese women and breast tumor progression. These results suggest the value of lifestyle and LC-PUFAs n-3 potential, in the context of obesity and breast cancer secondary/tertiary prevention.

Long-chain Omega-3 fatty acids supplementation and cognitive performance throughout adulthood: A 6-month randomized controlled trial

OBJECTIVE

To investigate whether omega-3 polyunsaturated fatty acids (n-3 PUFA) supplementation improve cognitive performance and if apolipoprotein E (APOE) genotype or age were effect modifiers.

METHODS

Healthy adults of 20 to 80 years old (n = 193) were completed a 6-month double-blind randomized controlled trial with two groups: 2.5 g/day of n-3 PUFA or a placebo. Primary outcomes were visuospatial ability and working memory and secondary outcomes were episodic memory and executive function, measured at baseline and 6 months.

RESULTS

Cognitive performances did not significantly differ between groups on primary or secondary outcomes after 6 months of treatment. APOE carriers and age were not effect modifiers for any outcomes. Those with low episodic memory scores and taking the n-3 PUFA supplement, significantly improved their scores (p = 0.043).

CONCLUSIONS

A 6-month n-3 PUFA supplementation did not improve cognitive performance in cognitively healthy adults and APOE status or age were not effect modifiers.

Why Have the Benefits of DHA Not Been Borne Out in the Treatment and Prevention of Alzheimer's Disease? A Narrative Review Focused on DHA Metabolism and Adipose Tissue

Docosahexaenoic acid (DHA), an omega-3 fatty acid rich in seafood, is linked to Alzheimer's Disease via strong epidemiological and pre-clinical evidence, yet fish oil or other DHA supplementation has not consistently shown benefit to the prevention or treatment of Alzheimer's Disease. Furthermore, autopsy studies of Alzheimer's Disease brain show variable DHA status, demonstrating that the relationship between DHA and neurodegeneration is complex and not fully understood. Recently, it has been suggested that the forms of DHA in the diet and plasma have specific metabolic fates that may affect brain uptake; however, the effect of DHA form on brain uptake is less pronounced in studies of longer duration. One major confounder of studies relating dietary DHA and Alzheimer's Disease may be that adipose tissue acts as a long-term depot of DHA for the brain, but this is poorly understood in the context of neurodegeneration. Future work is required to develop biomarkers of brain DHA and better understand DHA-based therapies in the setting of altered brain DHA uptake to help determine whether brain DHA should remain an important target in the prevention of Alzheimer's Disease.

Overview of age-related changes in psychomotor and cognitive functions in a prosimian primate, the gray mouse lemur (Microcebus murinus): Recent advances in risk factors and antiaging interventions

Aging is not homogeneous in humans and the determinants leading to differences between subjects are not fully understood. Impaired glucose homeostasis is a major risk factor for cognitive decline in middle-aged humans, pointing at the existence of early markers of unhealthy aging. The gray mouse lemur (Microcebus murinus), a small lemuriform Malagasy primate, shows relatively slow aging with decreased psychomotor capacities at middle-age (around 5-year old). In some cases (∼10%), it spontaneously leads to pathological aging. In this case, some age-related deficits, such as severe cognitive decline, brain atrophy, amyloidosis, and glucoregulatory imbalance are congruent with what is observed in humans. In the present review, we inventory the changes occurring in psychomotor and cognitive functions during healthy and pathological aging in mouse lemur. It includes a summary of the cerebral, metabolic, and cellular alterations that occur during aging and their relation to cognitive decline. As nutrition is one of the major nonpharmacological antiaging strategies with major potential effects on cognitive performances, we also discuss its role in brain functions and cognitive decline in this species. We show that the overall approach of aging studies in the gray mouse lemur offers promising ways of investigation for understanding, prevention, and treatments of pathological aging in humans.

A 16-week randomized controlled trial of a fish oil and whey protein-derived supplement to improve physical performance in older adults losing autonomy-A pilot study

BACKGROUND

Low functional capacity may lead to the loss of independence and institutionalization of older adults. A nutritional intervention within a rehabilitation program may attenuate loss of muscle function in this understudied population.

OBJECTIVE

This pilot study assessed the feasibility for a larger RCT of a nutritional supplementation in older adults referred to an outpatient assessment and rehabilitation program.

METHODS

Participants were randomized to receive a supplement (EXP: 2g fish oil with 1500 IU vitamin D3 1x/d + 20-30g whey protein powder with 3g leucine 2x/d) or isocaloric placebo (CTR: corn oil + maltodextrin powder) for 16 weeks. Handgrip and knee extension strength (using dynamometry), physical performance tests and plasma phospholipid n-3 fatty acids (using GCMS) were evaluated at weeks 0, 8 and 16; and lean soft tissue mass (using DXA), at weeks 0 and 16.

RESULTS

Over 2 years, 244 patients were screened, 46 were eligible (18.9%), 20 were randomized, 10 completed the study (6 CTR, 4 EXP). Median age was 87 y (77-94 y; 75% women) and gait speed was 0.69 m/s; 55% had low strength, and all performed under 420m on the 6-minute walk test, at baseline. Overall self-reported compliance to powder and oil was high (96% and 85%) but declined at 16 weeks for fish oil (55%). The EXP median protein intake surpassed the target 1.2-1.5 g/kg/d, without altering usual diet. Proportions of plasma phospholipid EPA and DHA increased significantly 3- and 1.5-fold respectively, at week 8 in EXP, with no change in CTR. Participants were able to complete most assessments with sustained guidance.

CONCLUSION

Because of low eligibility, the pilot study was interrupted and deemed non-feasible; adherence to rigorous study assessments and to supplements was adequate except for long-term fish oil. The non-amended protocol may be applied to populations with greater functional capacity.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04454359.

Specialized Pro-Resolving Lipid Mediators in Neonatal Cardiovascular Physiology and Diseases

Cardiovascular disease remains a leading cause of mortality worldwide. Unresolved inflammation plays a critical role in cardiovascular diseases development. Specialized Pro-Resolving Mediators (SPMs), derived from long chain polyunsaturated fatty acids (LCPUFAs), enhances the host defense, by resolving the inflammation and tissue repair. In addition, SPMs also have anti-inflammatory properties. These physiological effects depend on the availability of LCPUFAs precursors and cellular metabolic balance. Most of the studies have focused on the impact of SPMs in adult cardiovascular health and diseases. In this review, we discuss LCPUFAs metabolism, SPMs, and their potential effect on cardiovascular health and diseases primarily focusing in neonates. A better understanding of the role of these SPMs in cardiovascular health and diseases in neonates could lead to the development of novel therapeutic approaches in cardiovascular dysfunction.

Cerebral effect of optimized Allium sativum oil-loaded chitosan nanorods: GC-MS analysis and in vitro/in vivo evaluation

The chemical constituents of Allium sativum (garlic) oil were investigated using the GC/MS technique after silylation, and the presence of several fatty acids and their esters was revealed. The most dominant was 9,12-octadecadienoic acid (linoleic acid), a precursor of arachidonic acid, which is essential for brain development. Garlic oil-loaded chitosan nanoparticles (GCNs) were prepared to enhance its cerebral effects, and to mask its odor and taste. Two-level orthogonal factorial design, followed by regression analysis, was used to study the influence of different formulation variables. GCN3, the formula with the smallest particle size and the highest mucoadhesion, was selected as the optimized one. Transmission electron microscopy showed that GCN3 has a short nanorod-shape outline. We aimed to investigate the influence of orally administered GCN3 compared to the plain garlic oil (GO), on ciprofloxacin-induced (CPX) neurotoxicity in rats and the probable underlying mechanisms. The results show the significantly higher neurological curative effect of GCN3 compared to GO, and its greater antidepression-like and antianxiety-like potential via the alteration of brain neurotransmitter levels and inhibition of oxidative stress and inflammatory pathways. The histopathological examination showed the higher capability of GCN3 to repair the damage induced by CPX in the cerebral cortex, hippocampus area and substantia nigra brain sections. Similar results were proved immunohistochemically using Cox-2 antibody. The nanoencapsulation of GO represents a promising strategy for brain-targeting.

Proportions of long-chain ω-3 fatty acids in erythrocyte membranes of Canadian adults: Results from the Canadian Health Measures Survey 2012-2015

BACKGROUND

The Omega-3 Index (OI) is a proposed marker of coronary artery disease (CAD) risk. Another index, the EPA/arachidonic acid (AA) ratio has also been proposed as a possible risk marker for CAD.

OBJECTIVE

Our primary objective was to characterize the Canadian population subgroups that have an undesirable OI (<4%, associated with high CAD risk) and to identify the participants' characteristics most strongly associated with the OI. Our secondary objective was to identify the characteristics most strongly associated with the EPA/AA ratio.

DESIGN

Data from 4025 adult participants of cycles 3 and 4 (2012-2015) of the cross-sectional Canadian Health Measures Survey were pooled. Adjusted mean proportions of erythrocyte membrane ω-3 (n-3) fatty acids, total ω-6 fatty acids, and ratios were analyzed by sociodemographic, health, and lifestyle characteristics using covariate-adjusted models.

RESULTS

The mean OI was 4.5%. Almost 40% of Canadians had an undesirable (<4%) OI. ω-3 supplement use, fish intake, and race were the variables most strongly associated with OI scores. The prevalence of undesirable OI was significantly higher among participants consuming fish less than twice a week (43.8%; 95% CI: 39.0%, 48.6%) than among those consuming more fish (12.7%; 95% CI: 7.8%, 19.9%), among smokers (62.7%; 95% CI: 52.9%, 71.7%) than nonsmokers (33.4%; 95% CI: 29.4%, 37.7%), in whites (42.7%; 95% CI: 38.2%, 47.4%) than in Asians (23.0%; 95% CI: 15.4%, 33.0%), and in adults aged 20-39 y (49.6%; 95% CI: 42.3%, 56.9%) than in those aged 60-79 y (24.4%; 95% CI: 21.0%, 28.1%). ω-3 supplement intake and fish intake were the characteristics most strongly associated with EPA/AA. All P ≤ 0.05.

CONCLUSIONS

An important proportion of Canadian adults has an undesirable (<4%) OI, with higher prevalence in some subgroups. Further assessment is required to determine the value and feasibility of an increase in the population's OI to the currently proposed target of ≥8% as a potential public health objective.

Oxylipin patterns in human colon adenomas

OBJECTIVE

Cyclooxygenase (COX)-derived prostaglandin E₂ (PGE₂) is an important lipid mediator in colorectal carcinoma (CRC) pathogenesis. Other lipid mediators derived from lipoxygenases (LOX) have also been implicated in neoplastic processes in the colon. In this study we aimed to characterize lipid mediators, so called oxylipins, in human colon adenomatous polyps.

DESIGN

We quantified oxylipins in healthy colon tissue and colorectal adenoma tissue procured during routine colonoscopy examinations. Lipid metabolite profiles were analyzed by liquid chromatography-tandem mass spectrometry.

RESULTS

Adenoma tissue showed a distinct prostaglandin profile as compared to normal colon mucosa. Interestingly, PGE₂ was not higher in adenoma tissue as compared to normal mucosa. In contrast, we found significantly lower levels of prostaglandin D₂, prostaglandin J₂, and prostaglandin D₁ in adenoma tissue. Furthermore, levels of 5-LOX and 12-LOX pathway products were clearly increased in adenoma biopsy samples. We also investigated the effect of aspirin treatment on prostaglandin profiles in adenoma tissue in a subset of patients and found a trend towards decreased prostaglandin levels in response to aspirin.

CONCLUSION

The human data presented here show specific changes of oxylipin profiles in colon adenoma tissue with decreased prostaglandin D₂ levels as well as increased 5- and 12-LOX metabolites.

In vitro dissolution behaviour and absorption in humans of a novel mixed l-lysine salt formulation of EPA and DHA

INTRODUCTION

Supplements with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are generally oil-based formulations containing their triacylglycerols, phospholipids or ethyl-esters (EE). Recently, a l-lysine salt of carboxylic EPA and DHA became available (Lys-FFA), which necessitated to study its oral absorption and plasma kinetics in humans.

OBJECTIVES

The in vitro dissolution characteristics, oral bioavailability and 48 h plasma profiles of EPA and DHA (as triacylglycerides) of Lys-FFA, relative to a commercially available oil-based EE supplement.

METHODS

Dissociation of the lysine from the FFAs was studied in vitro applying simulated gastric (12 h) and intestinal (3 h) conditions. In an open label, randomized, two-way cross-over design, oral administration of Lys-FFA (500 mg EPA plus 302 mg DHA) versus EE (504 mg EPA plus 378 mg DHA) was studied over 48 h, in eight female volunteers. Plasma profiles of EPA and DHA were described by Area Under the Curve (AUC; 0-12 h), C_max and T_max.

RESULTS

Dissolution studies with Lys-FFA showed complete dissociation under both conditions. In volunteers Lys-FFA showed rapid absorption and high bioavailability indicated by significant differences in both the AUC_0-12hr and C_max when compared to the EE comparator (p<0.001), with AUC_0-12hr which was for EPA 5 times higher with Lys-FFA than with the EE formulation.

CONCLUSION

This first-in-man study of Lys-FFA demonstrated rapid absorption of EPA and DHA and a considerably higher bioavailability compared to an EE supplement under fasting conditions. The release and absorption characteristics from this solid form offer several new options in terms of formulation technology and dosing.

Low Levels of Omega-3 Long-Chain Polyunsaturated Fatty Acids Are Associated with Bone Metastasis Formation in Premenopausal Women with Breast Cancer: A Retrospective Study

In the present study, we investigated various biochemical, clinical, and histological factors associated with bone metastases in a large cohort of pre- and postmenopausal women with breast cancer. Two hundred and sixty-one consecutive women with breast cancer were included in this study. Breast adipose tissue specimens were collected during surgery. After having established the fatty acid profile of breast adipose tissue by gas chromatography, we determined whether there were differences associated with the occurrence of bone metastases in these patients. Regarding the clinical and histological criteria, a majority of the patients with bone metastases (around 70%) had tumors with a luminal phenotype and 59% of them showed axillary lymph node involvement. Moreover, we found a negative association between the levels of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) in breast adipose tissue and the development of bone metastases in premenopausal women. No significant association was observed in postmenopausal women. In addition to a luminal phenotype and axillary lymph node involvement, low levels of n-3 LC-PUFA in breast adipose tissue may constitute a risk factor that contributes to breast cancer bone metastases formation in premenopausal women.

EPA and DHA differentially modulate monocyte inflammatory response in subjects with chronic inflammation in part via plasma specialized pro-resolving lipid mediators: A randomized, double-blind, crossover study

BACKGROUND AND AIMS

The independent effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on chronic inflammation through their downstream lipid mediators, including the specialized pro-resolving lipid mediators (SPM), remain unstudied. Therefore, we compared the effects of EPA and DHA supplementation on monocyte inflammatory response and plasma polyunsaturated fatty acids (PUFA) SPM lipidome.

METHODS

After a 4-week lead-in phase (baseline), 9 men and 12 postmenopausal women (50-75 years) with chronic inflammation received two phases of 10-week supplementation with 3 g/day EPA and DHA in a random order, separated by a 10-week washout.

RESULTS

Compared with baseline, EPA and DHA supplementation differently modulated LPS-stimulated monocyte cytokine expression. EPA lowered TNFA (p < 0.001) whereas DHA reduced TNFA (p < 0.001), IL6 (p < 0.02), MCP1 (p < 0.03), and IL10 (p < 0.01). DHA lowered IL10 expression relative to EPA (p = 0.03). Relative to baseline, EPA, but not DHA, decreased the ratios of TNFA/IL10 and MCP1/IL10 (both p < 0.01). EPA and DHA also significantly changed plasma PUFA SPM lipidome by replacing n-6 AA derivatives with their respective derivatives including 18-hydroxy-EPA (+5 fold by EPA) and 17- and 14-hydroxy-DHA (+3 folds by DHA). However, DHA showed a wider effect than EPA by also significantly increasing EPA derivatives and DPA-derived SPM at a greater expense of AA derivatives. Different groups of PUFA derivatives mediated the differential effects of EPA and DHA on monocyte cytokine expression.

CONCLUSIONS

EPA and DHA had distinct effects on monocyte inflammatory response with a broader effect of DHA in attenuating pro-inflammatory cytokines. These differential effects were potentially mediated by different groups of PUFA derivatives, suggesting immunomodulatory activities of SPM and their intermediates.

Polyunsaturated fatty acid biosynthesis pathway and genetics. implications for interindividual variability in prothrombotic, inflammatory conditions such as COVID-19✰,✰✰,★,★★

COVID-19 symptoms vary from silence to rapid death, the latter mediated by both a cytokine storm and a thrombotic storm. SARS-CoV (2003) induces Cox-2, catalyzing the synthesis, from highly unsaturated fatty acids (HUFA), of eicosanoids and docosanoids that mediate both inflammation and thrombosis. HUFA balance between arachidonic acid (AA) and other HUFA is a likely determinant of net signaling to induce a healthy or runaway physiological response. AA levels are determined by a non-protein coding regulatory polymorphisms that mostly affect the expression of FADS1, located in the FADS gene cluster on chromosome 11. Major and minor haplotypes in Europeans, and a specific functional insertion-deletion (Indel), rs66698963, consistently show major differences in circulating AA (>50%) and in the balance between AA and other HUFA (47-84%) in free living humans; the indel is evolutionarily selective, probably based on diet. The pattern of fatty acid responses is fully consistent with specific genetic modulation of desaturation at the FADS1-mediated 20:3→20:4 step. Well established principles of net tissue HUFA levels indicate that the high linoleic acid and low alpha-linoleic acid in populations drive the net balance of HUFA for any individual. We predict that fast desaturators (insertion allele at rs66698963; major haplotype in Europeans) are predisposed to higher risk and pathological responses to SARS-CoV-2 could be reduced with high dose omega-3 HUFA.

Comparison of pharmacokinetics of omega-3 fatty acid supplements in monoacylglycerol or ethyl ester in humans: a randomized controlled trial

Background

A diet low in omega-3 fatty acids (n-3 FA) results in low plasma concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the two main long chain n-3 FA. n-3 FA supplements on the market are esterified in triglycerides (TG) or ethyl ester (EE); the latter is absorbed less than other esterification forms. The objective of this study was to test and compare the pharmacokinetics of n-3 FA esterified in monoacylglycerides (MAG), a predigested form, with the EE form.

Methods

This study was a randomized, double-blind, crossover, controlled, clinical trial. Ten men and ten women between 18 and 60 years old were recruited. Participants received a single oral dose of 3 g of n-3 FA esterified in EE or MAG. Eleven blood samples were collected over 24 h post-dose. Plasma total lipids were extracted, methylated, and analyzed using gas chromatography.

Results

After receiving the MAG form, plasma EPA and DHA peaked at a concentration 3 and 2.5 times higher, respectively, than with the EE form. When provided in MAG form, n-3 FA plasma concentration during the absorption phase was on average 3–5 times higher than in EE form. When n-3 FAs were provided esterified in MAG, their concentration 24 h post-dose was higher than in EE. Males had a lower n-3 FA plasma concentration than females when n-3 FAs were provided in EE but there was no sexe difference when provided in MAG.

Conclusions

Plasma concentration of DHA and EPA was higher when provided in MAG than EE form.

ISSFAL Official Statement Number 6: The importance of measuring blood omega-3 long chain polyunsaturated fatty acid levels in research

A statement on measuring blood omega-3 long chain polyunsaturated fatty acid levels was developed and edited based on input from ISSFAL members and accepted by vote of the ISSFAL Board of Directors. Summary of Statement: Omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) levels at baseline and post-intervention should be assessed and reported in future research to evaluate the efficacy of n-3 LCPUFA supplementation: b ecause; 1. there are numerous factors that affect n-3 LCPUFA levels in humans as described in the systematic literature review [1]; 2. assessing intake of n-3 LCPUFA from the diet and/or supplements is not sufficient to accurately determine n-3 LCPUFA levels in humans; 3. some studies do not provide sufficient doses of n-3 LCPUFA to produce a significant impact on bloodstream/organ content and there is substantial variability in the uptake of n-3 LPCUFA into tissues between individuals. In secondary analyses, clinical trials should consider the influence of fatty acid status (baseline, endpoint and change from baseline to endpoint) on the outcome variables.

Serum triglycerides in Alzheimer disease: Relation to neuroimaging and CSF biomarkers

OBJECTIVE

To investigate the association of triglyceride (TG) principal component scores with Alzheimer disease (AD) and the amyloid, tau, neurodegeneration, and cerebrovascular disease (A/T/N/V) biomarkers for AD.

METHODS

Serum levels of 84 TG species were measured with untargeted lipid profiling of 689 participants from the Alzheimer's Disease Neuroimaging Initiative cohort, including 190 cognitively normal older adults (CN), 339 with mild cognitive impairment (MCI), and 160 with AD. Principal component analysis with factor rotation was used for dimension reduction of TG species. Differences in principal components between diagnostic groups and associations between principal components and AD biomarkers (including CSF, MRI and [¹⁸F]fluorodeoxyglucose-PET) were assessed with a generalized linear model approach. In both cases, the Bonferroni method of adjustment was used to correct for multiple comparisons.

RESULTS

The 84 TGs yielded 9 principal components, 2 of which, consisting of long-chain, polyunsaturated fatty acid-containing TGs (PUTGs), were significantly associated with MCI and AD. Lower levels of PUTGs were observed in MCI and AD compared to CN. PUTG principal component scores were also significantly associated with hippocampal volume and entorhinal cortical thickness. In participants carrying the APOE ε4 allele, these principal components were significantly associated with CSF β-amyloid_1-42 values and entorhinal cortical thickness.

CONCLUSION

This study shows that PUTG component scores were significantly associated with diagnostic group and AD biomarkers, a finding that was more pronounced in APOE ε4 carriers. Replication in independent larger studies and longitudinal follow-up are warranted.

Updates to the n-3 polyunsaturated fatty acid biosynthesis pathway: DHA synthesis rates, tetracosahexaenoic acid and (minimal) retroconversion

N-3 polyunsaturated fatty acids (PUFA) and the numerous families of lipid mediators derived from them collectively regulate numerous biological processes. The mechanisms by which n-3 PUFA regulate biological processes begins with an understanding of the n-3 biosynthetic pathway that starts with alpha-linolenic acid (18:3n-3) and is commonly thought to end with the production of docosahexaenoic acid (DHA, 22:6n-3). However, our understanding of this pathway is not as complete as previously believed. In the current review we provide a background of the evidence supporting the pathway as currently understood and provide updates from recent studies challenging three central dogma of n-3 PUFA metabolism. By building on nearly three decades of research primarily in cell culture and oral dosing studies, recent evidence presented focuses on in vivo kinetic modelling and compound-specific isotope abundance studies in rodents and humans that have been instrumental in expanding our knowledge of the pathway. Specifically, we highlight three main updates to the n-3 PUFA biosynthesis pathway: (1) DHA synthesis rates cannot be as low as previously believed, (2) DHA is both a product and a precursor to tetracosahexaenoic acid (24:6n-3) and (3) increases in EPA in response to DHA supplementation are not the result of increased retroconversion.

Single-Dose SDA-Rich Echium Oil Increases Plasma EPA, DPAn3, and DHA Concentrations

The omega-3 (n3) polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with health benefits. The primary dietary source of EPA and DHA is seafood. Alpha-linoleic acid (ALA) has not been shown to be a good source for EPA and DHA; however, stearidonic acid (SDA)-which is naturally contained in echium oil (EO)-may be a more promising alternative. This study was aimed at investigating the short-term n3 PUFA metabolism after the ingestion of a single dose of EO. Healthy young male subjects (n = 12) ingested a single dose of 26 g of EO after overnight fasting. Plasma fatty acid concentrations and relative amounts were determined at baseline and 2, 4, 6, 8, 24, 48, and 72 h after the ingestion of EO. During the whole examination period, the participants received standardized nutrition. Plasma ALA and SDA concentrations increased rapidly after the single dose of EO. Additionally, EPA and DPAn3 concentrations both increased significantly by 47% after 72 h compared to baseline; DHA concentrations also significantly increased by 21% after 72 h. To conclude, EO increases plasma ALA, SDA, EPA, DPAn3, and DHA concentrations and may be an alternative source for these n3 PUFAs.

Compound-specific isotope analysis reveals no retroconversion of DHA to EPA but substantial conversion of EPA to DHA following supplementation: a randomized control trial

BACKGROUND

It has long been believed that DHA supplementation increases plasma EPA via the retroconversion pathway in mammals. However, in rodents this increase in EPA is likely due to a slower metabolism of EPA, but this has never been tested directly in humans.

OBJECTIVE

The aim of this study was to use the natural variations in 13C:12C ratio (carbon-13 isotopic abundance [δ13C]) of n-3 PUFA supplements to assess n-3 PUFA metabolism following DHA or EPA supplementation in humans.

METHODS

Participants (aged 21.6 ± 2.2 y) were randomly assigned into 1 of 3 supplement groups for 12 wk: 1) olive oil control, 2) ∼3 g/d DHA, or 3) ∼3 g/d EPA. Blood was collected before and after the supplementation period, and concentrations and δ13C of plasma n-3 PUFA were determined.

RESULTS

DHA supplementation increased (P < 0.05) plasma EPA concentrations by 130% but did not affect plasma δ13C-EPA (-31.0 ± 0.30 to -30.8 ± 0.19, milliUrey ± SEM, P > 0.05). In addition, EPA supplementation did not change plasma DHA concentrations (P > 0.05) but did increase plasma δ13C-DHA (-27.9 ± 0.2 to -25.6 ± 0.1, P < 0.05) toward δ13C-EPA of the supplement (-23.5 ± 0.22). EPA supplementation increased plasma concentrations of EPA and docosapentaenoic acid (DPAn-3) by 880% and 200%, respectively, and increased plasma δ13C-EPA (-31.5 ± 0.2 to -25.7 ± 0.2) and δ13C-DPAn-3 (-28.9 ± 0.3 to -25.0 ± 0.1) toward δ13C-EPA of the supplement.

CONCLUSIONS

In this study, we show that the increase in plasma EPA following DHA supplementation in humans does not occur via retroconversion, but instead from a slowed metabolism and/or accumulation of plasma EPA. Furthermore, substantial amounts of supplemental EPA can be converted into DHA. δ13C of n-3 PUFA in humans is a powerful and underutilized tool that can track dietary n-3 PUFA and elucidate complex metabolic questions. This trial was registered at clinicaltrials.gov as NCT03378232.

Comparing docosahexaenoic acid (DHA) concomitant with neoadjuvant chemotherapy versus neoadjuvant chemotherapy alone in the treatment of breast cancer (DHA WIN): protocol of a double-blind, phase II, randomised controlled trial

INTRODUCTION

Neoadjuvant chemotherapy for breast cancer treatment is prescribed to facilitate surgery and provide confirmation of drug-sensitive disease, and the achievement of pathological complete response (pCR) predicts improved long-term outcomes. Docosahexaenoic acid (DHA) has been shown to reduce tumour growth in preclinical models when combined with chemotherapy and is known to beneficially modulate systemic immune function. The purpose of this trial is to investigate the benefit of DHA supplementation in combination with neoadjuvant chemotherapy in patients with breast cancer.

METHODS AND ANALYSIS

This is a double-blind, phase II, randomised controlled trial of 52 women prescribed neoadjuvant chemotherapy to test if DHA supplementation enhances chemotherapy efficacy. The DHA supplementation group will take 4.4 g/day DHA orally, and the placebo group will take an equal fat supplement of vegetable oil. The primary outcome will be change in Ki67 labelling index from prechemotherapy core needle biopsy to definitive surgical specimen. The secondary endpoints include assessment of (1) DHA plasma phospholipid content; (2) systemic immune cell types, plasma cytokines and inflammatory markers; (3) tumour markers for apoptosis and tumour infiltrating lymphocytes; (4) rate of pCR in breast and in axillary nodes; (5) frequency of grade 3 and 4 chemotherapy-associated toxicities; and (6) patient-perceived quality of life. The trial has 81% power to detect a significant between-group difference in Ki67 index with a two-sided t-test of less than 0.0497, and accounts for 10% dropout rate.

ETHICS AND DISSEMINATION

This study has full approval from the Health Research Ethics Board of Alberta - Cancer Committee (Protocol #: HREBA.CC-18-0381). We expect to present the findings of this study to the scientific community in peer-reviewed journals and at conferences. The results of this study will provide evidence for supplementing with DHA during neoadjuvant chemotherapy treatment for breast cancer.

TRIAL REGISTRATION NUMBER

NCT03831178.

Dynamics of the human skin mediator lipidome in response to dietary ω-3 fatty acid supplementation

Nutritional supplementation with fish oil or ω-3 (n-3) polyunsaturated fatty acids (PUFAs) has potential benefits for skin inflammation. Although the differential metabolism of the main n-3PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) could lead to distinct activities, there are no clinical studies comparing their relative efficacy in human skin. Following a 10-wk oral supplementation of healthy volunteers and using mass spectrometry-based lipidomics, we found that n-3PUFA mainly affected the epidermal mediator lipidome. EPA was more efficient than DHA in reducing production of arachidonic acid–derived lipids, and both n-3PUFA lowered N-acyl ethanolamines. In UV radiation–challenged skin (3 times the minimum erythemal dose), EPA attenuated the production of proinflammatory lipids, whereas DHA abrogated the migration of Langerhans cells, as assessed by immunohistochemistry. Interestingly, n-3PUFA increased the infiltration of CD4⁺ and CD8⁺ T cells but did not alter the erythemal response, either the sunburn threshold or the resolution of erythema, as assessed by spectrophotometric hemoglobin index readings. As EPA and DHA differentially impact cutaneous inflammation through changes in the network of epidermal lipids and dendritic and infiltrating immune cells, they should be considered separately when designing interventions for cutaneous disease.—Kendall, A. C., Pilkington, S. M., Murphy, S. A., Del Carratore, F., Sunarwidhi, A. L., Kiezel-Tsugunova, M., Urquhart, P., Watson, R. E. B., Breitling, R., Rhodes, L. E., Nicolaou, A. Dynamics of the human skin mediator lipidome in response to dietary ω-3 fatty acid supplementation.

Omega-3 PUFA metabolism and brain modifications during aging

In Canada, 5.5 million (16% of Canadians) adults are >65 years old and projections suggest this number will be approximately 20% of Canadians by 2024. A major concern regarding old age is a decline in health, especially if this entails a loss of self-sufficiency and independence caused by a decline in cognition. The brain contains 60% of fat and is one of the most concentrated organs in long chain omega-3 fatty acids such as docosahexaenoic acid (DHA). During aging, there are physiological modifications in the metabolism of lipids that could also have consequences on brain structure and levels of DHA. This review will hence discuss the physiological modifications in the metabolism of lipids during aging with a focus on long chain omega-3 and omega-6 fatty acids and also outline the structural and functional modifications of the brain during aging including brain lipid modifications and its relation to higher levels of DHA and cognition. Therefore, in this review, we outline the importance of collecting more data on the biology of aging since it might highly improve our understanding about what are «normal» modifications occurring during aging and what can become pathological.

Omega-3 fatty acids and nonalcoholic fatty liver disease in adults and children: where do we stand?

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic fatty liver disease worldwide. The incidence of NAFLD parallels the prevalence of obesity. Moreover, NAFLD can progress to nonalcoholic steatohepatitis (NASH), cirrhosis and primary hepatocellular cancer (HCC). As such, NAFLD has become a major public health concern. We discuss recent clinical trials and meta-analyses evaluating the efficacy of C20-22 ω3 polyunsaturated fatty acids (PUFA) to attenuate preexisting NAFLD in adults and children.

RECENT FINDINGS

Humans with NAFLD and NASH; and preclinical mouse models of NASH, have a high abundance of hepatic saturated (SFA) and monounsaturated (MUFA) fat, but a low abundance of hepatic C20-22 ω3 PUFA. This change in hepatic fat type and abundance is associated with hepatic lipotoxicity, inflammation, oxidative stress and fibrosis. Recent meta-analyses and clinical trials evaluated the capacity of C20-22 ω3 PUFA dietary supplementation to improve health outcomes in adults and children with preexisting NAFLD. Diets supplemented with docosahexaenoic acid (DHA, 22 : 6,ω3) alone or with eicosapentaenoic acid (EPA, 20 : 5,ω3) are tolerated and effective at lowering liver fat in NAFLD patients. However, outcomes are mixed with respect to C20-22 ω3 PUFA attenuation of more severe NAFLD markers, such as hepatic injury, inflammation and fibrosis.

SUMMARY

These studies suggest that dietary supplementation with C20-22 ω3 PUFA should be considered as a viable and effective option to lower liver fat in obese adults and children with NAFLD.

Non-dietary factors associated with n-3 long-chain PUFA levels in humans - a systematic literature review

Numerous health benefits are attributed to the n-3 long-chain PUFA (n-3 LCPUFA); EPA and DHA. A systematic literature review was conducted to investigate factors, other than diet, that are associated with the n-3 LCPUFA levels. The inclusion criteria were papers written in English, carried out in adult non-pregnant humans, n-3 LCPUFA measured in blood or tissue, data from cross-sectional studies, or baseline data from intervention studies. The search revealed 5076 unique articles of which seventy were included in the qualitative synthesis. Three main groups of factors potentially associated with n-3 LCPUFA levels were identified: (1) unmodifiable factors (sex, genetics, age), (2) modifiable factors (body size, physical activity, alcohol, smoking) and (3) bioavailability factors (chemically bound form of supplements, krill oil v. fish oil, and conversion of plant-derived α-linolenic acid (ALA) to n-3 LCPUFA). Results showed that factors positively associated with n-3 LCPUFA levels were age, female sex (women younger than 50 years), wine consumption and the TAG form. Factors negatively associated with n-3 LCPUFA levels were genetics, BMI (if erythrocyte EPA and DHA levels are &lt;5·6 %) and smoking. The evidence for girth, physical activity and krill oil v. fish oil associated with n-3 LCPUFA levels is inconclusive. There is also evidence that higher ALA consumption leads to increased levels of EPA but not DHA. In conclusion, sex, age, BMI, alcohol consumption, smoking and the form of n-3 LCPUFA are all factors that need to be taken into account in n-3 LCPUFA research.

Docosahexaenoic acid is both a product of and a precursor to tetracosahexaenoic acid in the rat

Tetracosahexaeoic acid (THA; 24:6n-3) is thought to be the immediate precursor of DHA in rodents; however, the relationship between THA and DHA metabolism has not been assessed in vivo. Here, we infused unesterified ²H₅-THA and ¹³C₂₂-DHA, at a steady state, into two groups of male Long-Evans rats and determined the synthesis-secretion kinetics, including daily synthesis-secretion rates of all 20-24 carbon n-3 PUFAs. We determined that the synthesis-secretion coefficient (a measure of the capacity to synthesize a given fatty acid) for the synthesis of DHA from plasma unesterified THA to be 134-fold higher than for THA from DHA. However, when considering the significantly higher endogenous plasma unesterified DHA pool, the daily synthesis-secretion rates were only 7-fold higher for DHA synthesis from THA (96.3 ± 31.3 nmol/d) compared with that for THA synthesis from DHA (11.4 ± 4.1 nmol/d). Furthermore, plasma unesterified THA was converted to DHA and secreted into the plasma at a 2.5-fold faster rate than remaining as THA itself (26.2 ± 6.3 nmol/d), supporting THA's primary role as a precursor to DHA. In conclusion, using a 3 h infusion model in rats, we demonstrate for the first time in vivo that DHA is both a product and a precursor to THA.

Association of oily fish intake, sex, age, BMI and APOE genotype with plasma long-chain n-3 fatty acid composition

n-3 Fatty acids are associated with better cardiovascular and cognitive health. However, the concentration of EPA, DPA and DHA in different plasma lipid pools differs and factors influencing this heterogeneity are poorly understood. Our aim was to evaluate the association of oily fish intake, sex, age, BMI and APOE genotype with concentrations of EPA, DPA and DHA in plasma phosphatidylcholine (PC), NEFA, cholesteryl esters (CE) and TAG. Healthy adults (148 male, 158 female, age 20-71 years) were recruited according to APOE genotype, sex and age. The fatty acid composition was determined by GC. Oily fish intake was positively associated with EPA in PC, CE and TAG, DPA in TAG, and DHA in all fractions (P≤0·008). There was a positive association between age and EPA in PC, CE and TAG, DPA in NEFA and CE, and DHA in PC and CE (P≤0·034). DPA was higher in TAG in males than females (P<0·001). There was a positive association between BMI and DPA and DHA in TAG (P<0·006 and 0·02, respectively). APOE genotype×sex interactions were observed: the APOE4 allele associated with higher EPA in males (P=0·002), and there was also evidence for higher DPA and DHA (P≤0·032). In conclusion, EPA, DPA and DHA in plasma lipids are associated with oily fish intake, sex, age, BMI and APOE genotype. Such insights may be used to better understand the link between plasma fatty acid profiles and dietary exposure and may influence intake recommendations across population subgroups.

The Differential Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid on Cardiometabolic Risk Factors: A Systematic Review

A large body of evidence supports the cardioprotective effects of the long-chain omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). There is increasing interest in the independent effects of EPA and DHA in the modulation of cardiometabolic risk factors. This systematic review aims to appraise the latest available evidence of the differential effects of EPA and DHA on such risk factors. A systematic literature review was conducted up to May 2017. Randomised controlled trials were included if they met strict eligibility criteria, including EPA or DHA > 2 g/day and purity ≥ 90%. Eighteen identified articles were included, corresponding to six unique studies involving 527 participants. Both EPA and DHA lowered triglyceride concentration, with DHA having a greater triglyceride-lowering effect. Whilst total cholesterol levels were largely unchanged by EPA and DHA, DHA increased high-density lipoprotein (HDL) cholesterol concentration, particularly HDL₂, and increased low-density lipoprotein (LDL) cholesterol concentration and LDL particle size. Both EPA and DHA inhibited platelet activity, whilst DHA improved vascular function and lowered heart rate and blood pressure to a greater extent than EPA. The effects of EPA and DHA on inflammatory markers and glycaemic control were inconclusive; however both lowered oxidative stress. Thus, EPA and DHA appear to have differential effects on cardiometabolic risk factors, but these need to be confirmed by larger clinical studies.

Retroconversion is a minor contributor to increases in eicosapentaenoic acid following docosahexaenoic acid feeding as determined by compound specific isotope analysis in rat liver

Dietary docosahexaenoic acid (DHA, 22:6n-3) not only increases blood and tissue levels of DHA, but also eicosapentaenoic acid (EPA, 20:5n-3). It is generally believed that this increase is due to DHA retroconversion to EPA, however, a slower conversion of α-linolenic acid (ALA, 18:3n-3) derived EPA to downstream metabolic products (i.e. slower turnover of EPA) is equally plausible. In this study, 21-day old Long Evans rats were weaned onto an ALA only or DHA + ALA diet for 12 weeks. Afterwards, livers were collected and the natural abundance ¹³C-enrichment was determined by compound specific isotope analysis (CSIA) of liver EPA by isotope ratio mass-spectrometry and compared to dietary ALA and DHA ¹³C-enrichment. Isotopic signatures (per mil, ‰) for liver EPA were not different (p > 0.05) between the ALA only diet (−25.89 ± 0.39 ‰, mean ± SEM) and the DHA + ALA diet (−26.26 ± 0.40 ‰), suggesting the relative contribution from dietary ALA and DHA to liver EPA did not change. However, with DHA feeding estimates of absolute EPA contribution from ALA increased 4.4-fold (147 ± 22 to 788 ± 153 nmol/g) compared to 3.2-fold from DHA (91 ± 14 to 382 ± 13 nmol/g), respectively. In conclusion, CSIA of liver EPA in rats following 12-weeks of dietary DHA suggests that retroconversion of DHA to EPA is a relatively small contributor to increases in EPA, and that this increase in EPA is largely coming from elongation/desaturation of ALA.

Metabolism of uniformly labeled 13C-eicosapentaenoic acid and 13C-arachidonic acid in young and old men

Background: Plasma eicosapentaenoic acid (EPA) and arachidonic acid (AA) concentrations increase with age.Objective: The aim of this study was to evaluate EPA and AA metabolism in young and old men by using uniformly labeled carbon-13 (¹³C) fatty acids.Design: Six young (∼25 y old) and 6 old (∼75 y old) healthy men were recruited. Each participant consumed a single oral dose of 35 mg ¹³C-EPA and its metabolism was followed in the course of 14 d in the plasma and 28 d in the breath. After the washout period of ≥28 d, the same participants consumed a single oral dose of 50 mg ¹³C-AA and its metabolism was followed for 28 d in plasma and breath.Results: There was a time × age interaction for ¹³C-EPA (P_{time × age} = 0.008), and the shape of the postprandial curves was different between young and old men. The ¹³C-EPA plasma half-life was ∼2 d for both young and old men (P = 0.485). The percentage dose recovered of ¹³C-EPA per hour as ¹³CO₂ and the cumulative β-oxidation of ¹³C-EPA did not differ between young and old men. At 7 d, however, old men had a >2.2-fold higher plasma ¹³C-DHA concentration synthesized from ¹³C-EPA compared with young men (P_age = 0.03). ¹³C-AA metabolism was not different between young and old men. The ¹³C-AA plasma half-life was ∼4.4 d in both young and old participants (P = 0.589).Conclusions: The metabolism of ¹³C-AA was not modified by age, whereas ¹³C-EPA metabolism was slightly but significantly different in old compared with young men. The higher plasma ¹³C-DHA seen in old men may be a result of slower plasma DHA clearance with age. This trial was registered at clinicaltrials.gov as NCT02957188.

Omega-3 polyunsaturated fatty acids as a treatment strategy for nonalcoholic fatty liver disease

Obese and type 2 diabetic (T2DM) patients have a high prevalence of nonalcoholic fatty liver disease (NAFLD). NAFLD is a continuum of chronic liver diseases ranging from benign hepatosteatosis to nonalcoholic steatohepatitis (NASH), cirrhosis and primary hepatocellular cancer (HCC). Because of its strong association with the obesity epidemic, NAFLD is rapidly becoming a major public health concern worldwide. Surprisingly, there are no FDA approved NAFLD therapies; and current therapies focus on the co-morbidities associated with NAFLD, namely, obesity, hyperglycemia, dyslipidemia, and hypertension. The goal of this review is to provide background on the disease process, discuss human studies and preclinical models that have examined treatment options. We also provide an in-depth rationale for the use of dietary ω3 polyunsaturated fatty acid (ω3 PUFA) supplements as a treatment option for NAFLD. This focus is based on recent studies indicating that NASH patients and preclinical mouse models of NASH have low levels of hepatic C_20-22 ω3 PUFA. This decline in hepatic PUFA may account for the major phenotypic features associated with NASH, including steatosis, inflammation and fibrosis. Finally, our discussion will address the strengths and limitations of ω3 PUFA supplements use in NAFLD therapy.

Effect of DHA supplementation on oxylipin levels in plasma and immune cell stimulated blood

INTRODUCTION

EPA and DHA cause different physiological effects, which are in many cases mediated via their oxidative metabolites (oxylipins). However, metabolism studies investigating the effect of either EPA or DHA on comprehensive oxylipin patterns are lacking.

MATERIAL AND METHODS

The short and long term (1, 3, 6, and 12 week) effect of 1076mg/d DHA (free of EPA) on free (unesterified) oxylipin concentrations in plasma and lipopolysacharid (LPS) stimulated blood of 12 healthy men (mean age 25.1 ± 1.5 years) was investigated.

RESULTS

After DHA supplementation, plasma levels of all DHA-oxylipins (HDHAs, EpDPEs, DiHDPEs) significantly increased (up to 600%) in a time-dependent fashion. Oxylipins of EPA and arachidonic acid (AA) were also affected. Whereas a slight increase in several EPA-derived hydroxy-FAs (including the RvE1 precursor 18-HEPE) and dihydroxy-FAs was observed after DHA supplementation, a trend to a slight decline in AA-derived oxylipin levels was found. In LPS stimulated blood, it is shown that DHA supplementation significantly reduces the ability of immune cells to form AA-derived COX (TXB2 and PGB2) and 12-LOX (12-HETE) eicosanoids. While no increase in EPA COX metabolites was found, n-3 PUFA 12-LOX metabolites of EPA (12-HEPE) and DHA (14-HDHA) were highly induced.

CONCLUSION

We demonstrated that DHA supplementation causes a time-dependent shift in the entire oxylipin profile suggesting a cross-linked metabolism of PUFAs and subsequent formation of oxygenated lipid mediators.

Lipid functions in skin: Differential effects of n-3 polyunsaturated fatty acids on cutaneous ceramides, in a human skin organ culture model

Ceramides are important for skin health, with a multitude of species found in both dermis and epidermis. The epidermis contains linoleic acid-Ester-linked Omega-hydroxylated ceramides of 6-Hydroxy-sphingosine, Sphingosine and Phytosphingosine bases (CER[EOH], CER[EOS] and CER[EOP], respectively), that are crucial for the formation of the epidermal barrier, conferring protection from environmental factors and preventing trans-epidermal water loss. Furthermore, a large number of ceramides, derivatives of the same sphingoid bases and various fatty acids, are produced by dermal and epidermal cells and perform signalling roles in cell functions ranging from differentiation to apoptosis.

Supplementation with the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown promise as therapeutic agents in a number of inflammatory skin conditions, altering the lipid profile of the skin and production of bioactive lipids such as the eicosanoids, docosanoids and endocannabinoids. In this study we wished to investigate whether EPA and DHA could also affect the ceramide profile in epidermis and dermis, and, in this way, contribute to formation of a robust lipid barrier and ceramide-mediated regulation of skin functions.

Ex vivo skin explants were cultured for 6 days, and supplemented with EPA or DHA (50 μM). Liquid chromatography coupled to tandem mass spectrometry with electrospray ionisation was used to assess the prevalence of 321 individual ceramide species, and a number of sphingoid bases, phosphorylated sphingoid bases, and phosphorylated ceramides, within the dermis and epidermis.

EPA augmented dermal production of members of the ceramide families containing Non-hydroxy fatty acids and Sphingosine or Dihydrosphingosine bases (CER[NS] and CER[NDS], respectively), while epidermal CER[EOH], CER[EOS] and CER[EOP] ceramides were not affected. DHA did not significantly affect ceramide production. Ceramide-1-phosphate levels in the epidermis, but not the dermis, increased in response to EPA, but not DHA.

This ex vivo study shows that dietary supplementation with EPA has the potential to alter the ceramide profile of the skin, and this may contribute to its anti-inflammatory profile. This has implications for formation of the epidermal lipid barrier, and signalling pathways within the skin mediated by ceramides and other sphingolipid species. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

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Omega-3 fatty acid supplementation alters ex vivo skin ceramide profiles

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Eicosapentaenoic acid (EPA) increases dermal ceramides with non-hydroxy fatty acids (CER[NS] and CER[NDS])

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EPA increases ceramide-1-phosphate (C1P) in the epidermis but not dermis

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Long-chain linoleic-acid-containing ceramides were unaltered by EPA or docosahexaenoic acid (DHA)

Low long chain omega-3 fatty acid status in middle-aged women

INTRODUCTION

Long-chain (LC) omega-3 fatty acids (n-3 PUFAs) have beneficial effects on cardiovascular health and cognitive decline. Several studies have shown that the LC n-3 PUFA status in women in western countries is low. The aim of this study was to assess the LC n-3 PUFA status in middle-aged German women and to identify variables that might affect the status.

MATERIAL AND METHODS

From the nationwide and cross-sectional German VitaMinFemin study, fatty acid levels in the erythrocyte membrane (% of total erythrocyte fatty acids) were ascertained for 446 women (40-60 years).

RESULTS

The average omega-3 index (% of eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) of the total study population was 5.49±1.17%. A total of 62.8% of women had a low omega-3 index (>4-6%). The omega-3 index was affected by age and smoking, with slightly higher values in women ≥50 years (p=0.032) and non-smokers (p=0.002). Women taking hormonal contraceptives showed a lower EPA level (p<0.001), a lower ratio of EPA/alpha-linoleic acid (p<0.001) and a higher ratio of DHA/EPA (p<0.001) than women without hormonal contraception.

CONCLUSION

The low LC n-3 PUFA status in middle-aged German women (40-60 years) is related to an increased risk of cardiovascular diseases and possibly other diseases and should therefore be improved. Further studies are needed to determine the influence of estrogen on the effect on LC n-3 PUFA status.

The phospholipid composition of the human entorhinal cortex remains relatively stable over 80 years of adult aging

Membrane lipid composition is altered in the brain during the pathogenesis of several age-related neurodegenerative diseases, including Alzheimer's disease. The entorhinal cortex is one of the first regions of the brain to display the neuropathology typical of Alzheimer's disease, yet little is known about the changes that occur in membrane lipids within this brain region during normal aging (i.e., in the absence of dementia). In the present study, the phospholipid composition of mitochondrial and microsomal membranes from human entorhinal cortex was examined for any changes over the adult lifespan (18-98 years). Overall, changes in several molecular phospholipids were seen with age in the entorhinal cortex across both membranes. The proportion of total phosphatidylcholine within the mitochondrial fraction increased within the entorhinal cortex with age, while total mitochondrial phosphatidylethanolamine decreased. Many mitochondrial phosphatidylethanolamines containing docosahexaenoic acid increased with age; however, this did not translate into an overall age-related increase in total mitochondrial docosahexaenoic acid. The most abundant phospholipid present within the human brain, PC 16:0_18:1, also increased with age within the mitochondrial membranes of the entorhinal cortex. When compared to other regions of the brain, the phospholipid composition of the entorhinal cortex remains relatively stable in adults over the lifespan in the absence of dementia.

Quantitative profiling of endocannabinoids and related N-acylethanolamines in human CSF using nano LC-MS/MS

Endocannabinoids, a class of lipid messengers, have emerged as crucial regulators of synaptic communication in the CNS. Dysregulation of these compounds has been implicated in many brain disorders. Although some studies have identified and quantified a limited number of target compounds, a method that provides comprehensive quantitative information on endocannabinoids and related N-acylethanolamines (NAEs) in cerebrospinal fluid (CSF) is currently lacking, as measurements are challenging due to low concentrations under normal physiological conditions. Here we developed and validated a high-throughput nano LC-ESI-MS/MS platform for the simultaneous quantification of endocannabinoids (anandamide and 2-arachidonoylglycerol), ten related NAEs, and eight additional putatively annotated NAEs in human CSF. Requiring only 200 μl of CSF, our method has limits of detection from 0.28 to 61.2 pM with precisions of relative SD <15% for most compounds. We applied our method to CSF from 45 healthy humans and demonstrated potential age and gender effects on concentrations of endocannabinoids and NAEs. Notably, our results show that docosahexaenoylethanolamide concentrations increase with age in males. Our method may offer new opportunities to gain insight into regulatory functions of endocannabinoids in the context of (ab)normal brain function.

Fatty acid profile in cord blood of neonates born to optimally controlled gestational diabetes mellitus

OBJECTIVE

To evaluate the fatty acid profile of cord blood phospholipids (PL), cholesteryl esters (CE), triglycerides (TG) and non-esterified fatty acids (NEFA) in neonates born to mothers with gestational diabetes mellitus (GDM) compared to non-diabetic mothers.

METHODS

The offspring of 30 pregnant women (15 non-diabetic controls, 15 with diet- or insulin-controlled GDM) were recruited before delivery. Cord blood was collected. After lipid extraction, PL, CE, TG and NEFA were separated by thin layer chromatography and analysed by gas chromatography.

RESULTS

In GDM vs. control mothers, maternal glycated haemoglobin (A_1C, mean±SD) was not different between groups: 5.3±0.5% vs. 5.3±0.3% (p=0.757), respectively. Cord plasma fatty acids were not different in TG, CE and NEFA between GDM and non-diabetic mothers. However, in PL, levels of palmitate, palmitoleate, oleate, vaccinate and di-homo-gamma-linolenate were significantly lower, with a trend for lower arachidonate (p=0.078), in neonates born to GDM mothers compared to controls.

CONCLUSION

In contrast to other studies on cord blood docosahexaenoic acid (DHA) levels in GDM mothers, we did not found lower levels of DHA in cord PL, CE, TG or NEFA in neonates born to GDM compared to non-diabetic mothers.

Effects of docosahexaenoic acid supplementation on PUFA levels in red blood cells and plasma

INTRODUCTION

Polyunsaturated fatty acids (PUFA) are metabolized in a complex network of elongation, desaturation and beta oxidation.

MATERIAL AND METHODS

The short (1 and 3 wk), and long term (6 and 12 wk) effect of 1076mg/d docosahexaenoic acid (DHA, free of eicosapentaenoic acid (EPA)) on (absolute) PUFA concentrations in plasma and red blood cells (RBC) of 12 healthy men (mean age 25.1±1.5 years) was investigated.

RESULTS

RBC DHA concentrations significantly (p<0.001) increased from 28±1.6µg/mL to 38±2.0µg/mL (wk 1), 52±3.3µg/mL (wk 3), 68±2.6µg/mL (wk 6), and 79±3.5µg/mL (wk 12). Arachidonic acid (AA) concentrations declined in response to DHA treatment, while the effect was more pronounced in plasma (wk 0: 183±9.9µg/mL, wk 12: 139±8.0µg/mL, -24%, p<0.001) compared to RBC (wk 0: 130±3.7µg/mL, wk 12: 108±4.0µg/mL, -16%, p=0.001). Furthermore, an increase of EPA concentrations in plasma (wk 0: 15±1.5µg/mL, wk 1:19±1.6µg/mL, wk 3: 27±2.3µg/mL, wk 6: 23±1.2µg/mL, wk 12: 25±1.7µg/mL, p<0.001) and RBC (wk 0: 4.7±0.33µg/mL, wk 1: 6.7±1.3µg/mL, wk 3: 8.0±0.66µg/mL, wk 6: 6.9±0.44µg/mL, wk 12: 6.7±0.45µg/mL, n.s.) was observed suggesting a retroconversion of DHA to EPA.

CONCLUSION

Based on PUFA concentrations we showed that DHA supplementation results in increased EPA levels, whereas it is not known if this impacts the formation of EPA-derived lipid mediators. Furthermore, shifts in the entire PUFA pattern after supplementation of EPA or DHA should be taken into account when discussing differential physiological effects of EPA and DHA.

Plasma Phosphatidylcholines Fatty Acids in Men with Squamous Cell Esophageal Cancer: Chemoradiotherapy Improves Abnormal Profile

BACKGROUND Abnormal metabolism of fatty acids (FA) is considered to play a role in human cancers, including esophageal cancer (EC). Nevertheless, there have been only a few studies dealing with the influence of the chemotherapy or radiotherapy on the plasma FA profiles. In this work we compared FA in plasma phosphatidylcholine (PC) of the patients with squamous EC and healthy subjects and investigated changes in the FA spectrum during neoadjuvant chemoradiotherapy (CRT). MATERIAL AND METHODS Forty-two men with squamous EC were compared with age-matched healthy controls. The EC group was subjected to concurrent neoadjuvant CRT. We analyzed FA in plasma PC before and after CRT. RESULTS The EC group was characterized by increased levels of both saturated and monounsaturated FA, associated with an increased index of SCD1 (stearoyl-CoA desaturase-1). Moreover, decreased levels of linoleic acid and total polyunsaturated FA (PUFA) n-6 were found in EC patients. The CRT was accompanied by increased docosahexaenoic acid and total PUFA n-3 content in plasma PC, concurrently with the decrease of estimated activity of SCD1. CONCLUSIONS We found that patients with EC had altered FA profile in plasma PC, which could be related to abnormal FA metabolism in cancer (e.g., altered synthesis de novo, b-oxidation, desaturation, and elongation). The described changes in FA profiles during CRT could be involved in favorable functioning of CRT. Further studies investigating the plasma FA compositions and their changes due to CRT in EC patients are warranted.

Risk factors associated with plasma omega-3 fatty acid levels in patients with suspected coronary artery disease

INTRODUCTION

We sought to determine the associations between plasma eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels and various cardiovascular risk factors and with the use of fish oil supplements (FOS).

PATIENTS AND METHODS

Patients with suspected coronary artery disease (CAD) undergoing cardiac catheterization (n=433) were studied. Serum fatty acid (FA) composition, the concentrations of lipids and biomarkers of oxidative stress, and dietary/lifestyle factors were measured.

RESULTS

FOS use was associated with a higher plasma EPA+DHA levels (3.7±1.5 vs. 2.6±1.1%, p<0.0001). However, there was no relationship between FOS dose (mg/day) and EPA+DHA levels in 76 patients reporting FOS use (r=-0.21, p=0.07). Lower levels were inversely associated with risk factor profiles including lower ApoB100/ApoA1 ratios (p<0.001).

DISCUSSION AND CONCLUSIONS

Higher EPA+DHA levels characterized patients with lower CAD risk. The lack of relations between FOS dose and plasma EPA+DHA levels likely reflects uncaptured variability in EPA+DHA content of supplements.