Specific methylation of plasma nonesterified fatty acids in a one-step reaction

Efficacy and Safety of Habitual Consumption of a Food Supplement Containing Miraculin in Malnourished Cancer Patients: The CLINMIR Pilot Study

Taste disorders (TDs) are common among systemically treated cancer patients and negatively impact their nutritional status and quality of life. The novel food approved by the European Commission (EFSA), dried miracle berries (DMB), contains the natural taste-modifying protein miraculin. DMB, also available as a supplement, has emerged as a possible alternative treatment for TDs. The present study aimed to evaluate the efficacy and safety of habitual DMB consumption in malnourished cancer patients undergoing active treatment. An exploratory clinical trial was carried out in which 31 cancer patients were randomized into three arms [standard dose of DMB (150 mg DMB/tablet), high dose of DMB (300 mg DMB/tablet) or placebo (300 mg freeze-dried strawberry)] for three months. Patients consumed a DMB tablet or placebo daily before each main meal (breakfast, lunch, and dinner). Throughout the five main visits, electrochemical taste perception, nutritional status, dietary intake, quality of life and the fatty acid profile of erythrocytes were evaluated. Patients consuming a standard dose of DMB exhibited improved taste acuity over time (% change right/left side: -52.8 ± 38.5/-58.7 ± 69.2%) and salty taste perception (2.29 ± 1.25 vs. high dose: 2.17 ± 1.84 vs. placebo: 1.57 ± 1.51 points, p < 0.05). They also had higher energy intake (p = 0.075) and covered better energy expenditure (107 ± 19%). The quality of life evaluated by symptom scales improved in patients receiving the standard dose of DMB (constipation, p = 0.048). The levels of arachidonic (13.1 ± 1.8; 14.0 ± 2.8, 12.0 ± 2.0%; p = 0.004) and docosahexaenoic (4.4 ± 1.7; 4.1 ± 1.0; 3.9 ± 1.6%; p = 0.014) acids in erythrocytes increased over time after DMB intake. The standard dose of DMB increased fat-free mass vs. placebo (47.4 ± 9.3 vs. 44.1 ± 4.7 kg, p = 0.007). Importantly, habitual patients with DMB did not experience any adverse events, and metabolic parameters remained stable and within normal ranges. In conclusion, habitual consumption of a standard 150 mg dose of DMB improves electrochemical food perception, nutritional status (energy intake, fat quantity and quality, fat-free mass), and quality of life in malnourished cancer patients receiving antineoplastic treatment. Additionally, DMB consumption appears to be safe, with no changes in major biochemical parameters associated with health status. Clinical trial registered (NCT05486260).

Effect of Regular Consumption of a Miraculin-Based Food Supplement on Taste Perception and Nutritional Status in Malnourished Cancer Patients: A Triple-Blind, Randomized, Placebo-Controlled Clinical Trial-CLINMIR Pilot Protocol

Taste disorders are common among cancer patients undergoing chemotherapy, with a prevalence ranging from 20% to 86%, persisting throughout treatment. This condition leads to reduced food consumption, increasing the risk of malnutrition. Malnutrition is associated not only with worse treatment efficacy and poor disease prognosis but also with reduced functional status and quality of life. The fruit of Synsepalum dulcificum (Daniell), commonly known as miracle berry or miracle fruit, contains miraculin, a taste-modifying protein with profound effects on taste perception. The CLINMIR Protocol is a triple-blind, randomized, placebo-controlled clinical trial designed to evaluate the regular consumption of a food supplement containing a miraculin-based novel food, dried miracle berry (DMB), on the taste perception (measured through electrogustometry) and nutritional status (evaluated through the GLIM Criteria) of malnourished cancer patients under active antineoplastic treatment. To this end, a pilot study was designed with 30 randomized patients divided into three study arms (150 mg DMB + 150 mg freeze-dried strawberries, 300 mg DMB, or placebo) for three months. Throughout the five main visits, an exhaustive assessment of different parameters susceptible to improvement through regular consumption of the miraculin-based food supplement will be conducted, including electrical and chemical taste perception, smell perception, nutritional and morphofunctional assessment, diet, quality of life, the fatty acid profile of erythrocytes, levels of inflammatory and cancer-associated cytokines, oxidative stress, antioxidant defense system, plasma metabolomics, and saliva and stool microbiota. The primary anticipated result is that malnourished cancer patients with taste distortion who consume the miraculin-based food supplement will report an improvement in food taste perception. This improvement translates into increased food intake, thereby ameliorating their nutritional status and mitigating associated risks. Additionally, the study aims to pinpoint the optimal dosage that provides maximal benefits. The protocol adheres to the SPIRIT 2013 Statement, which provides evidence-based recommendations and is widely endorsed as an international standard for trial protocols. The clinical trial protocol has been registered at the platform for Clinical Trials (NCT05486260).

Effect of Gum Acacia on the Intestinal Bioavailability of n-3 Polyunsaturated Fatty Acids in Rats

Lipid emulsification is a technique that is being explored for improving the bioavailability of omega 3 (n-3) long chain (LC) fatty acid (FA). The nature of the emulsifiers can differently impact the lipid bioavailability via a modification of the lipolysis step. Among natural emulsifiers, gum acacia (GA), an indigestible polysaccharide, provides protective encapsulation of n-3 by forming a specifically crown-like shape around lipid drops, which could also impact the digestion step. Despite the interest in lipolysis rate, the impact of GA on lipid bioavailability has never been explored in a complete physiological context. Thus, we followed in a kinetics study the n-3 bioavailability in rat lymph, orally administered DHA-rich oil, formulated based on GA compared to the bulk phase form of the oil. The AUC values were significantly improved by +121% for total TG and by 321% for n-3 PUFA, specifically for EPA (+244%) and for DHA (+345%). Benefits of GA have also been related to the transport of FA in lymph, which was 2 h earlier (Tmax = 4 h), compared to the Tmax (6 h) obtained with the bulk phase oil. All the data showed that GA is one of the most favorable candidates of natural emulsifiers to improve n-3 bioavailability and their rate of absorption for health targets.

Effect of increased levels of dietary α-linolenic acid on the n-3 PUFA bioavailability and oxidative stress in rat

We investigated the impact of increased alpha-linolenic acid (ALA) dietary levels on its plasma bioavailability and its bioconversion in n-3 long chain poly unsaturated fatty acids during a 60-d kinetics and the oxidative stress potentially associated. Rats were submitted to a normolipidic diet providing 0, 3, 10 and 24% ALA of dietary lipids for 0, 15, 30 and 60 days. The lipid peroxidation and oxidative stress (nitric oxide (NO) contents and catalase (CAT), superoxide dismutase (SOD), gluthation peroxidase (GPx) activities) were studied in the liver and plasma. When the diet was deprived in n-3 PUFAs, ALA, (eicosanoic acid) EPA and docosahexaenoic acid (DHA) levels decreased in all lipid fractions of plasma and in red blood cell (RBC) lipids. The addition of ALA in the diet linearly improves its bioavailability and its bioconversion in EPA (R²=0.98). By providing 10 to 24% ALA in dietary lipids (LA/ALA, 1·6 and 5·5 respectively), ALA and EPA were more broadly packaged in all lipid fractions (triglyceride (TAG), cholesterol ester (CE) and free fatty acids (FFA)) of plasma from 15 to 30 days timeframe. Only 3% ALA was sufficient to promote the maximal bioconversion of ALA in DHA in phospholipid (PL) and TAG fractions. Additionally, the improvement of ALA bioconversion in EPA and DHA did not impact the oxidative stress markers and limiting lipid peroxidation. To conclude, this study demonstrated that in rat, 10% ALA in the lipid diet for 15-30 days promotes its bioavailability and its bioconversion and allowed the greatest levels in plasma and RBCs.

Docosahexaenoic and Eicosapentaenoic Intervention Modifies Plasma and Erythrocyte Omega-3 Fatty Acid Profiles But Not the Clinical Course of Children With Autism Spectrum Disorder: A Randomized Control Trial

Background

The pathogenesis of autism spectrum disorder (ASD) is under investigation and one of the main alterations relates to the metabolic and inflammatory system dysfunctions. Indeed, based on a possible deficit of omega-3 fatty acids (FAs) of patients with ASD and looking for an anti-inflammatory effect, dietary supplements with omega-3 fatty acids have been proposed. We aimed to evaluate differences in plasma and erythrocyte FA profiles and plasma cytokines in patients with infantile ASD after supplementation with docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids or placebo and both compared at baseline with a reference healthy group.

Methods

A double-blind, randomized placebo-controlled intervention with DHA/EPA for 6 months was carried out in 54 children between 2 and 6 years diagnosed with ASD. They were selected and randomly assigned into two groups: 19 children received 800 mg/day of DHA and 25 mg/day of EPA, or placebo. In addition, another reference group of 59 healthy children of the same age was included. Plasma lipids and cytokines, and FA profiles in plasma and erythrocytes were measured at baseline and after 6 months of treatment in ASD children, and at baseline in the reference group.

Results

There were no differences in demographic, anthropometric characteristics, and omega-3 intake between the healthy reference group and the ASD children at baseline. Children with ASD showed the higher plasma percentages of palmitic acid and total saturated FA and lower total omega-6 polyunsaturated FA (PUFA) compared with healthy children. An increased level of DHA and reduced EPA level in erythrocytes were detected in the ASD group vs. the reference group. After 6 months of treatment, the ASD group that received DHA enriched product significantly increased the plasma and erythrocyte percentages of DHA, but no differences were observed in the clinical test scores and other parameters as plasma cytokines between the two groups of ASD related to the intervention.

Conclusion

Spanish children with ASD exhibit an appropriate omega-3 FA status in plasma and erythrocytes. Neither a clinical improvement of ASD children nor a better anti-inflammatory or fatty acid state has been found after an intervention with DHA/EPA for 6 months. So, the prescription of n-3 LC-PUFA and other dietary supplements in ASD should be only indicated after a confirmed alteration of FA metabolism or omega-3 LC-PUFA deficiency evaluated by specific erythrocyte FA.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [NCT03620097].

Rapeseed Lecithin Increases Lymphatic Lipid Output and α-Linolenic Acid Bioavailability in Rats

BACKGROUND

Soybean lecithin, a plant-based emulsifier widely used in food, is capable of modulating postprandial lipid metabolism. With arising concerns of sustainability, alternative sources of vegetal lecithin are urgently needed, and their metabolic effects must be characterized.

OBJECTIVES

We evaluated the impact of increasing doses of rapeseed lecithin (RL), rich in essential α-linolenic acid (ALA), on postprandial lipid metabolism and ALA bioavailability in lymph-cannulated rats.

METHODS

Male Wistar rats (8 weeks old) undergoing a mesenteric lymph duct cannulation were intragastrically administered 1 g of an oil mixture containing 4% ALA and 0, 1, 3, 10, or 30% RL (5 groups). Lymph fractions were collected for 6 h. Lymph lipids and chylomicrons (CMs) were characterized. The expression of genes implicated in intestinal lipid metabolism was determined in the duodenum at 6 h. Data was analyzed using either sigmoidal or linear mixed-effects models, or one-way ANOVA, where appropriate.

RESULTS

RL dose-dependently increased the lymphatic recovery (AUC) of total lipids (1100 μg/mL·h per additional RL%; P = 0.010) and ALA (50 μg/mL·h per additional RL%; P = 0.0076). RL induced a faster appearance of ALA in lymph, as evidenced by the exponential decrease of the rate of appearance of ALA with RL (R2 = 0.26; P = 0.0064). Although the number of CMs was unaffected by RL, CM diameter was increased in the 30%-RL group, compared to the control group (0% RL), by 86% at 3-4 h (P = 0.065) and by 81% at 4-6 h (P = 0.0002) following administration. This increase was positively correlated with the duodenal mRNA expression of microsomal triglyceride transfer protein (Mttp; ρ= 0.63; P = 0.0052). The expression of Mttp and secretion-associated, ras-related GTPase 1 gene homolog B (Sar1b, CM secretion), carnitine palmitoyltransferase IA (Cpt1a) and acyl-coenzyme A oxidase 1 (Acox1, beta-oxidation), and fatty acid desaturase 2 (Fads2, bioconversion of ALA into long-chain n-3 PUFAs) were, respectively, 49%, 29%, 74%, 48%, and 55% higher in the 30%-RL group vs. the control group (P < 0.05).

CONCLUSIONS

In rats, RL enhanced lymphatic lipid output, as well as the rate of appearance of ALA, which may promote its subsequent bioavailability and metabolic fate.

Selective and fast methylation of free fatty acids directly in plasma for their individual analysis by gas chromatography- mass spectrometry

An analytical procedure for the rapid and selective derivatization of free fatty acids into methyl esters directly in plasma without transmethylation of lipid-bound fatty acids was developed for their analysis by gas chromatography-mass spectrometry. The methyl esters of free fatty acids were obtained by reaction with methyl iodide in the solution of dipolar aprotic solvents and in the presence of solid bases. The mechanism of the methylation reaction with these reagents was investigated. Optimal conditions for the selective methylation of free fatty acids were established using different dipolar aprotic solvents and different solid bases. The possible transmethylation of covalently bonded fatty acids from plasma lipids has been investigated under different experimental conditions in order to be avoided. Total methylation of free fatty acids was achieved in 1 min at room temperature using methyl iodide and anhydrous potassium carbonate or sodium carbonate in dimethyl sulfoxide. Under these conditions, transmethylation of lipid-bound fatty acids was avoided. The methyl esters can be injected directly from the reaction solvents. A plasma volume of 50 μL was used without special purification. The detection limits were around 0.1 ng/μL. The proposed method avoids the drawbacks of the previous methods used for the one-step analysis of individual free fatty acids in human plasma.

Reduced Levels and Disrupted Biosynthesis Pathways of Plasma Free Fatty Acids in First-Episode Antipsychotic-Naïve Schizophrenia Patients

Membrane phospholipid deficits have been well-documented in schizophrenia (SZ) patients. Free fatty acids (FFAs) partially come from the hydrolysis of membrane phospholipids and serve as the circulating pool of body fatty acids. These FFAs are involved in many important biochemical reactions such as membrane regeneration, oxidation, and prostaglandin production which may have important implications in SZ pathology. Thus, we compared plasma FFA levels and profiles among healthy controls (HCs), affective psychosis (AP) patients, and first-episode antipsychotic-naïve schizophrenia (FEANS) patients. A significant reduction of total FFAs levels was observed in SZ patients. Specifically, significant reductions of 16:0, 18:2n6c, and 20:4n6 levels were detected in FEANS patients but not in APs when compared with levels in HCs. Also, disrupted metabolism of fatty acids especially in saturated and n-6 fatty acid families were observed by comparing correlations between precursor and product fatty acid levels within each fatty acid family. These findings may suggest an increased demand of membrane regeneration, a homeostatic imbalance of fatty acid biosynthesis pathway and a potential indication of increased beta oxidation. Collectively, these findings could help us better understand the lipid metabolism with regard to SZ pathophysiology.

New fully automated gas chromatographic analysis of urinary S-phenylmercapturic acid in isotopic dilution using negative chemical ionization with isobutane as reagent gas

The determination of urinary S-phenylmercapturic acid (S-PMA) represents the most reliable biomarker to monitor the intake risk of airborne benzene. Recently, the European Chemical Agency deliberated new occupational exposure limits for benzene and recommended an S-PMA biological limit value of 2-μg/g creatinine. This limit is an order of magnitude lower than the previous one, and its determination constitutes a challenge in the analytical field. We developed and validated a method that allows the fully automated and sensitive determination of S-PMA by the use of gas-chromatography negative chemical ionization tandem mass spectrometry in isotopic dilution. For negative chemical ionization, we selected a mixture of 1% isobutane in argon as reactive gas, by studying its chemical ionization mechanism and optimal parameters compared with pure isobutane or pure methane. This gas mixture produces a more abundant signal of the target analyte than isobutane or methane, and it extended the operative lifetime of the ion source, enabling us to start a high-throughput approach of the S-PMA analysis. Moreover, energy-resolved mass spectrometry experiments were carried out to refine the MS/MS analysis conditions, testing nitrogen and argon as collision gases. The method optimization was pursued by a chemometric model by using the experimental design. The quantification limit for S-PMA was 0.10 μg/L. Accuracy (between 98.3% and 99.6%) and precision (ranging from 1.6% to 6.4%) were also evaluated. In conclusion, the newly developed assay represents a powerful tool for the robust, reliable, and sensitive quantification of urinary S-PMA, and because of its automation, it is well suited for application in large environmental and biological monitoring.

Utilizing centralized biorepository samples for biomarkers of cystic fibrosis lung disease severity

BACKGROUND

Circulating biomarkers reflective of lung disease activity and severity have the potential to improve patient care and accelerate drug development in CF. The objective of this study was to leverage banked specimens to test the hypothesis that blood-based biomarkers discriminate CF children segregated by lung disease severity.

METHODS

Banked serum samples were selected from children who were categorized into two extremes of phenotype associated with lung function ('mild' or 'severe') based on CF-specific data and were matched on age, gender, CFTR genotype, and P. aeruginosa infection status. Targeted inflammatory proteins, lipids, and discovery metabolite profiles were measured in these serum samples.

RESULTS

The severe cohort, characterized by a lower CF-specific FEV1 percentile, had significantly higher circulating concentrations of high sensitivity C-reactive protein, serum amyloid A, granulocyte colony stimulating factor, and calprotectin compared to the mild cohort. The mild cohort tended to have higher serum linoleic acid concentrations. The metabolite arabitol was lower in the severe cohort while other CF relevant metabolic pathways showed non-significant differences after adjusting for multiple comparisons. A sensitivity analysis to correct for biased estimates that may result from selecting subjects using an extremes of phenotype approach confirmed the protein biomarker findings.

CONCLUSIONS

Circulating inflammatory proteins differ in CF children segregated by lung function. These findings serve to demonstrate the value of maintaining centralized, high quality patient derived samples for future research, with linkage to clinical information to answer testable hypotheses in biomarker development.

Determination of free fatty acids in plasma by gas chromatography

A method was developed for determination of free fatty acids (FFAs) in plasma by gas chromatography. Plasma was extracted with 3 vol of methanol. Most cholesterol esters and triacylglycerols did not dissolve in the aqueous methanol. FFAs in the crude lipid solution were directly and selectively methylated with (trimethylsilyl)diazomethane at room temperature. Fatty acid methyl esters (FAMEs) formed were extracted with hexane, and nonreactive phospholipids were washed out with 95% methanol. The partially purified FAME preparation was analyzed by gas chromatography. The composition and amount of plasma FFAs closely approximated those obtained using two different methods.

Automated untargeted stable isotope assisted lipidomics of liver cells on high glucose shows alteration of sphingolipid kinetics

Untargeted lipidomics is a powerful tool to discover new biomarkers and to understand the physiology and pathology of lipids. The use of stable isotopes as tracers to investigate the kinetics of lipids is another tool able to supply dynamic information on lipid synthesis and catabolism. Coupling the two methodology is then very appealing in the study of lipid metabolism. The main issue to face is to perform thousands of calculations in order to obtain kinetic parameters starting from the MS raw data. An automated computerized routine able to do accomplish such task is presented in this paper. We analyzed the lipid kinetics of palmitic acid (PA) in hepatoma liver cells cultured in vitro in which insulin resistance has been induced by high glucose supplementation. The deuterated palmitate tracer (d5PA) was administered as a bolus and the cells were harvested daily for 48 h. 5dPA was incorporated into 326 monoisotopic compounds and in 84 of their [M + 1] isotopologues detected by high resolution orbitrap MS. The differences between the kinetics curves showed that at least four long chain triglycerides (TG) species incorporated more PA in glucose treated cells, while phosphocholines, sphingomyelins, mono- and di-glycerides and ceramides (Cer) incorporated less tracer under glucose treatment. Nevertheless, Cer amount was increased by glucose treatment. In conclusion we developed an automated powerful algorithm able to model simultaneously hundreds of kinetic curves obtained in a cell culture spiked with a stable isotope tracer, and to analyze the difference between the two different cell models.

Replacing Saturated Fat With Unsaturated Fat in Western Diet Reduces Foamy Monocytes and Atherosclerosis in Male Ldlr-/- Mice

OBJECTIVE

A Mediterranean diet supplemented with olive oil and nuts prevents cardiovascular disease in clinical studies, but the underlying mechanisms are incompletely understood. We investigated whether the preventive effect of the diet could be due to inhibition of atherosclerosis and foamy monocyte formation in Ldlr-/- mice fed with a diet in which milkfat in a Western diet (WD) was replaced with extra-virgin olive oil and nuts (EVOND). Approach and Results: Ldlr-/- mice were fed EVOND or a Western diet for 3 (or 6) months. Compared with the Western diet, EVOND decreased triglyceride and cholesterol levels but increased unsaturated fatty acid concentrations in plasma. EVOND also lowered intracellular lipid accumulation in circulating monocytes, indicating less formation of foamy monocytes, compared with the Western diet. In addition, compared with the Western diet, EVOND reduced monocyte expression of inflammatory cytokines, CD36, and CD11c, with decreased monocyte uptake of oxLDL (oxidized LDL [low-density lipoprotein]) ex vivo and reduced CD11c+ foamy monocyte firm arrest on vascular cell adhesion molecule-1 and E-selectin-coated slides in an ex vivo shear flow assay. Along with these changes, EVOND compared with the Western diet reduced the number of CD11c+ macrophages in atherosclerotic lesions and lowered atherosclerotic lesion area of the whole aorta and aortic sinus.

CONCLUSIONS

A diet enriched in extra-virgin olive oil and nuts, compared with a Western diet high in saturated fat, lowered plasma cholesterol and triglyceride levels, inhibited foamy monocyte formation, inflammation, and adhesion, and reduced atherosclerosis in Ldlr-/- mice.

A critical assessment of transmethylation procedures for n-3 long-chain polyunsaturated fatty acid quantification of lipid classes

Lipid transmethylation methods described in the literature are not always evaluated with care so to insure that the methods are effective, especially on food matrix or biological samples containing polyunsaturated fatty acid (PUFA). The aim of the present study was to select a method suitable for all lipid species rich in long chain n-3 PUFA. Three published methods were adapted and applied on individual lipid classes. Lipid (trans)methylation efficiency was characterized in terms of reaction yield and gas chromatography (GC) analysis. The acid-catalyzed method was unable to convert triglycerides and sterol esters, while the method using an incubation at a moderate temperature was ineffective on phospholipids and sterol esters. On the whole only the method using sodium methoxide and sulfuric acid was effective on lipid classes taken individually or in a complex medium. This study highlighted the use of an appropriate (trans)methylation method for insuring an accurate fatty acid composition.

Lack of effect of supplementation with EPA or DHA on platelet-monocyte aggregates and vascular function in healthy men

BACKGROUND AND AIMS

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish oil are postulated to have favourable effects on platelet, endothelial and vascular function. We investigated whether EPA has differential effects on in vivo platelet aggregation and other markers of cardiovascular risk compared to DHA.

METHODS AND RESULTS

Following a 2 wk run-in taking encapsulated refined olive oil, 48 healthy young men were randomly allocated using a parallel design to receive EPA-rich (3.1 g EPA/d) or DHA-rich (2.9 g DHA/d) triglyceride concentrates or refined olive oil (placebo), for a total supplementary lipid intake of 5 g/d. The specified primary outcome was change in platelet monocyte aggregates (PMA); secondary outcomes were capillary density, augmentation index, digital pulse volume measurements, 24 h ambulatory BP, plasma 8-isoprostanes-F2α. Changes in the proportions of DHA and EPA in erythrocytes and non-esterified fatty acid composition indicated compliance to the intervention. There was no significant treatment effect on PMA (P = 0.382); mean changes (%) (95% CI) were placebo -0.5 (-2.0, 1.04), EPA 0.4 (-0.8, 1.6), DHA 0.3 (-1.5, 2.0). R-QUICKI, an index of insulin sensitivity, was greater following EPA compared to placebo (P < 0.05). No other significant differences were noted.

CONCLUSION

Neither EPA- nor DHA-rich fish oil supplementation influence platelet-monocyte aggregation or several markers of vascular function after 6 wk in healthy young males. This trial was registered at clinicaltrials.gov as NCT01735357.

Myristic acid is associated to low plasma HDL cholesterol levels in a Mediterranean population and increases HDL catabolism by enhancing HDL particles trapping to cell surface proteoglycans in a liver hepatoma cell model

BACKGROUND

HDL-C plasma levels are modulated by dietary fatty acid (FA), but studies investigating dietary supplementation in FA gave contrasting results. Saturated FA increased HDL-C levels only in some studies. Mono-unsaturated FA exerted a slight effect while poly-unsaturated FA mostly increased plasma HDL-C.

AIMS

This study presents two aims: i) to investigate the relationship between HDL-C levels and plasma FA composition in a Sicilian population following a "Mediterranean diet", ii) to investigate if FA that resulted correlated with plasma HDL-C levels in the population study and/or very abundant in the plasma were able to affect HDL catabolism in an "in vitro" model of cultured hepatoma cells (HepG2).

RESULTS

plasma HDL-C levels in the population correlated negatively with myristic acid (C14:0, β = -0.24, p < 0.01), oleic acid (C18:1n9, β = -0.22, p < 0.01) and cis-11-Eicosenoic (C20:1n9, β = -0.19, p = 0.01) and positively with palmitoleic acid (C16:1, β = +0.19, p = 0.03). HepG2 cells were conditioned with FA before evaluating HDL binding kinetics, and only C14:0 increased HDL binding by a non-saturable pathway. After removal of heparan sulphate proteoglycans (HSPG) by heparinases HDL binding dropped by 29% only in C14:0 conditioned cells (p < 0.05). C14:0 showed also the highest internalization of HDL-derived cholesteryl esters (CE, +32% p = 0.01 vs. non-conditioned cells).

CONCLUSIONS

C14:0 was correlated with decreased plasma HDL-C levels in a Mediterranean population. C14:0 might reduce HDL-C levels by increasing HDL trapping to cell surface HSPG and CE stripping from bound HDL. Other mechanisms are to be investigated to explain the effects of other FA on HDL metabolism.

Erythrocyte DHA level as a biomarker of DHA status in specific brain regions of n-3 long-chain PUFA-supplemented aged rats

n-3 Long-chain PUFA (n-3 LC-PUFA), particularly EPA and DHA, play a key role in the maintenance of brain functions such as learning and memory that are impaired during ageing. Ageing is also associated with changes in the DHA content of brain membranes that could contribute to memory impairment. Limited studies have investigated the effects of ageing and n-3 LC-PUFA supplementation on both blood and brain fatty acid compositions. Therefore, we assessed the relationship between fatty acid contents in plasma and erythrocyte membranes and those in the hippocampus, striatum and cerebral cortex during ageing, and after a 5-month period of EPA/DHA supplementation in rats. In the blood, ageing was associated with an increase in plasma DHA content, whereas the DHA content remained stable in erythrocyte membranes. In the brain, ageing was associated with a decrease in DHA content, which was both region-specific and phospholipid class-specific. In EPA/DHA-supplemented aged rats, DHA contents were increased both in the blood and brain compared with the control rats. The present results demonstrated that n-3 LC-PUFA level in the plasma was not an accurate biomarker of brain DHA status during ageing. Moreover, we highlighted a positive relationship between the DHA levels in erythrocyte phosphatidylethanolamine (PE) and those in the hippocampus and prefrontal cortex in EPA/DHA-supplemented aged rats. Within the framework of preventive dietary supplementation to delay brain ageing, these results suggest the possibility of using erythrocyte PE DHA content as a reliable biomarker of DHA status in specific brain regions.

Plasma and erythrocyte membrane phospholipids and fatty acids in Italian general population and hemodialysis patients

Background

Dyslipidemia and abnormal phospholipid metabolism are frequent in uremic patients and increase their risk of cardiovascular disease (CVD): ω-3 polyunsaturated fatty acids (PUFAs) may reduce this risk in the general population. In this study we compared the plasma and erythrocyte cell membrane composition of PUFAs in a group of Caucasian hemodialysis (HD) patients and in a control group of healthy subjects and evaluated the erythrocyte/cell membrane fatty acid ratio as a marker of the dietary intake of phospholipids. The relationship between ω-3 and ω-6 fatty acids and the possible differences in PUFAs concentrations were also investigated.

Methods and results

After obtaining a fully informed consent, a total of ninety-nine HD patients and 160 non uremic control subjects from “Tor Vergata” University Hospital were enrolled into the study. None of them took antioxidant drugs or dietary supplements for at least 90 days prior to the observation. Blood samples were analysed by gas-chromatographic coupled to a mass spectrometric detector.

The daily intake of total calories, proteins, lipids and carbohydrates is significantly lower in HD patients than in controls (p < 0.001). Most plasma and erythrocyte PUFA were also reduced significantly in HD patients (p < 0.001).

Conclusions

Our results suggest that many classes of PUFAs are lacking in HD patients, due to the removal of nutrients during the dialysis and to persistent malnutrition. A dietary treatment addressed to increase plasma ω-3 PUFAs and to optimize ω-6/ω-3 ratio may exert a protective action and reduce the risk of CVD in HD patient.

Intermittent hypoxia exacerbates pancreatic β-cell dysfunction in a mouse model of diabetes mellitus

STUDY OBJECTIVES

The effects of intermittent hypoxia (IH) on pancreatic function in the presence of diabetes and the underlying mechanisms are unclear. We hypothesized that IH would exacerbate pancreatic β-cell dysfunction and alter the fatty acids in the male Tallyho/JngJ (TH) mouse, a rodent model of type 2 diabetes.

DESIGN

TH mice were exposed for 14 d to either 8 h of IH or intermittent air (IA), followed by an intraperitoneal glucose tolerance test (IPGTT) and tissue harvest. The effect of IH on insulin release was determined by using a β3-adrenergic receptor (AR) agonist.

MEASUREMENTS AND RESULTS

During IH, pancreatic tissue pO2 decreased from 20.4 ± 0.9 to 5.7 ± 2.6 mm Hg, as determined by electron paramagnetic resonance oximetry. TH mice exposed to IH exhibited higher plasma glucose levels during the IPGTT (P < 0.001) while the insulin levels tended to be lower (P = 0.06). Pancreatic islets of the IH group showed an enhancement of the caspase-3 staining (P = 0.002). IH impaired the β-AR agonist-mediated insulin release (P < 0.001). IH increased the levels of the total free fatty acids and saturated fatty acids (palmitic and stearic acids), and decreased levels of the monounsaturated fatty acids in the pancreas and plasma. Ex vivo exposure of pancreatic islets to palmitic acid suppressed insulin secretion and decreased islet cell viability.

CONCLUSIONS

Intermittent hypoxia increases pancreatic apoptosis and exacerbates dysfunction in a polygenic rodent model of diabetes. An increase in free fatty acids and a shift in composition towards long chain saturated fatty acid species appear to mediate these effects.

ELOVL2 gene polymorphisms are associated with increases in plasma eicosapentaenoic and docosahexaenoic acid proportions after fish oil supplement

Fish oil supplementation provides an inconsistent degree of protection from cardiovascular disease (CVD), which may be attributed to genetic variation. Single nucleotide polymorphisms (SNPs) in the elongation-of-very-long-chain-fatty-acids-2 (ELOVL2) gene have been strongly associated with plasma proportions of n-3 long-chain polyunsaturated fatty acids (LC-PUFA). We investigated the effect of genotype interaction with fish oil dosage on plasma n-3 LC-PUFA proportions in a parallel double-blind controlled trial, involving 367 subjects randomised to treatment with 0.45, 0.9 and 1.8 g/day eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (1.51:1) or olive oil placebo for 6 months. We genotyped 310 subjects for ELOVL2 gene SNPs rs3734398, rs2236212 and rs953413. At baseline, carriers of all minor alleles had lower proportions of plasma DHA than non-carriers (P = 0.021-0.030). Interaction between genotype and treatment was a significant determinant of plasma EPA (P < 0.0001) and DHA (P = 0.004-0.032). After the 1.8 g/day dose, carriers of ELOVL2 SNP minor alleles had approximately 30 % higher proportions of EPA (P = 0.002-0.004) and 9 % higher DHA (P = 0.013-0.017) than non-carriers. Minor allele carriers could therefore particularly benefit from a high intake of EPA and DHA in maintaining high levels of plasma n-3 PUFA conducive to protection from CVD.

Analysis of non-esterified fatty acids in human samples by solid-phase-extraction and gas chromatography/mass spectrometry

The determination of the fatty acid (FA) profile of lipid classes is essential for lipidomic analysis. We recently developed a GC/MS-method for the analysis of the FA profile of total FAs, i.e. the totality of bound and unbound FAs, in any given biological sample (TOFAs). Here, we present a method for the analysis of non-esterified fatty acids (NEFAs) in biological samples, i.e. the fraction that is present as extractable free fatty acids. Lipid extraction is performed according to Dole using 80/20 2-propanol/n-hexane (v/v), with 0.1% H2SO4. The fatty acid-species composition of this NEFA-fraction is determined as FAME after derivatization with our GC/MS-method on a BPX column (Shimadzu). Validation of the NEFA-method presented was performed in human plasma samples. The validated method has been used with human plasma, cells and tissues, as well as mammalian body fluids and tissue samples. The newly developed solid-phase-extraction (SPE)-GC-MS method allows the rapid separation of the NEFA-fraction from a neutral lipid extract of plasma samples. As a major advantage compared to G-FID-methods, GC-MS allows the use of stable isotope labeled fatty acid precursors to monitor fatty acid metabolism.

Impact of nutrition on serum levels of docosahexaenoic acid among Omani children with autism

OBJECTIVES

Autism is a lifelong neurodevelopmental disorder of early childhood. Dietary supplementation of the ω-3 fatty acid (docosahexaenoic acid [DHA]) during prenatal and postnatal life is considered a protective dietary intervention strategy to minimize the risk for autism spectrum disorder (ASD). To our knowledge, no relevant studies have been conducted in the Middle East investigating the status of DHA among children with autism during early childhood. The aim of this study was to investigate the serum levels and dietary intake status of DHA among Omani children recently diagnosed with ASD.

METHODS

The present case-control study involved 80 Omani children (<5 y), 40 cases and 40 controls matched for age and sex. A semi-quantitative food frequency questionnaire was used to assess dietary intake of all the participants, while serum levels of DHA were measured using high-performance liquid chromatography.

RESULTS

Our results showed that children with ASD had lower dietary consumption of foodstuff containing DHA, as well as lower serum levels of DHA than controls.

CONCLUSION

The present finding from Oman supports the view of other studies that there are low serum levels of DHA among children with ASD.

Unsaturated long chain free fatty acids are input signals of the Salmonella enterica PhoP/PhoQ regulatory system

The Salmonella enterica serovar Typhimurium PhoP/PhoQ system has largely been studied as a paradigmatic two-component regulatory system not only to dissect structural and functional aspects of signal transduction in bacteria but also to gain knowledge about the versatile devices that have evolved allowing a pathogenic bacterium to adjust to or counteract environmental stressful conditions along its life cycle. Mg(2+) limitation, acidic pH, and the presence of cationic antimicrobial peptides have been identified as cues that the sensor protein PhoQ can monitor to reprogram Salmonella gene expression to cope with extra- or intracellular challenging conditions. In this work, we show for the first time that long chain unsaturated free fatty acids (LCUFAs) present in Salmonella growth medium are signals specifically detected by PhoQ. We demonstrate that LCUFAs inhibit PhoQ autokinase activity, turning off the expression of the PhoP-dependent regulon. We also show that LCUFAs exert their action independently of their cellular uptake and metabolic utilization by means of the β-oxidative pathway. Our findings put forth the complexity of input signals that can converge to finely tune the activity of the PhoP/PhoQ system. In addition, they provide a new potential biochemical platform for the development of antibacterial strategies to fight against Salmonella infections.

Bioassay-guided supercritical fluid extraction of cyclooxygenase-2 inhibiting substances in Plantago major L

INTRODUCTION

Selective extraction of plant materials is advantageous for obtaining extracts enriched with desired constituents, thereby reducing the need for subsequent chromatography purification. Such compounds include three cyclooxygenase-2 (COX-2) inhibitory substances in Plantago major L. targeted in this investigation: α-linolenic acid (α-LNA) (18:3 ω-3) and the triterpenic acids ursolic acid and oleanolic acid.

OBJECTIVE

To investigate the scope for tuning the selectivity of supercritical fluid extraction (SFE) using bioassay guidance, and Soxhlet extraction with dichloromethane as solvent as a reference technique, to optimise yields of these substances.

METHOD

Extraction parameters were varied to optimise extracts' COX-2/COX-1 inhibitory effect ratios. The crude extracts were purified initially using a solid phase extraction (SPE) clean-up procedure and the target compounds were identified with GC-MS, LC-ESI-MS and LC-ESI-MS² using GC-FID for quantification.

RESULTS

α-LNA was preferentially extracted in dynamic mode using unmodified carbon dioxide at 40°C and 172 bar, at a 0.04% (w/w) yield with a COX-2/COX-1 inhibitory effect ratio of 1.5. Ursolic and oleanolic acids were dynamically extracted at 0.25% and 0.06% yields, respectively, with no traces of (α-LNA) and a COX-2/COX-1-inhibitory effect ratio of 1.1 using 10% (v/v) ethanol as polar modifier at 75°C and 483 bar. The Soxhlet extracts had ursolic acid, oleanolic acid and αLNA yields up to 1.36%, 0.34% and 0.15%, respectively, with a COX-2/COX-1 inhibitory effect ratio of 1.2.

CONCLUSION

The target substances can be extracted selectively by bioassay guided optimisation of SFE conditions.

Association of marine-origin n-3 polyunsaturated fatty acids consumption and functional mobility in the community-dwelling oldest old

OBJECTIVE

To examine whether habitual dietary intake of marine-origin n-3 polyunsaturated fatty acids (MOPUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with functional mobility in the community-dwelling oldest old, 85 years or older, who are at high risk for physical disability.

DESIGN

A cross-sectional study.

SETTING

A community-based survey conducted at university research center or home-based.

PARTICIPANTS

Four hundred seventeen (189 men, 228 women) out of 542 participants in the baseline examination of the Tokyo Oldest Old Survey on Total Health, a community-based ongoing longitudinal study among the oldest old living in the center of Japan.

MEASUREMENTS

Habitual dietary intake of MOPUFA was assessed by the brief-type self-administered diet history questionnaire (BDHQ), and functional mobility was assessed by the timed up and go test. Plasma inflammatory biomarkers (C-reactive protein, interleukin-6 and tumor necrosis factor-α) were measured. We evaluated the cross-sectional association between habitual intake of MOPUFA and functional mobility using multivariate logistic regression analysis. Prior to the analysis, validation of BDHQ in this study was confirmed among 190 participants (96 men, 94 women) based on the EPA and DHA concentrations in the erythrocyte membrane phospholipids as reference.

RESULTS

Moderate correlation between estimated dietary intake of EPA/DHA and concentration of EPA/DHA in the erythrocyte membrane phospholipids was obtained (Spearman's r=0.29-0.58, p<0.01). Multivariate logistic regression analysis revealed that a lower habitual intake of EPA+DHA was significantly associated with poor functional mobility in men but not in women (OR (95% CI) per 1 SD increase of EPA+DHA intake; 0.55 (0.33-0.91), 0.88 (0.59-1.32), men and women respectively).

CONCLUSIONS

Habitual intake of MOPUFA was associated with functional mobility in community-dwelling oldest old men.

Genetic variation at the FADS1-FADS2 gene locus influences delta-5 desaturase activity and LC-PUFA proportions after fish oil supplement

Delta-5 and delta-6 desaturases (D5D and D6D) are key enzymes in endogenous synthesis of long-chain PUFAs. In this sample of healthy subjects (n = 310), genotypes of single nucleotide polymorphisms (SNPs) rs174537, rs174561, and rs3834458 in the FADS1-FADS2 gene cluster were strongly associated with proportions of LC-PUFAs and desaturase activities estimated in plasma and erythrocytes. Minor allele carriage associated with decreased activities of D5D (FADS1) (5.84 × 10(-19) ≤ P ≤ 4.5 × 10(-18)) and D6D (FADS2) (6.05 × 10(-8) ≤ P ≤ 4.20 × 10(-7)) was accompanied by increased substrate and decreased product proportions (0.05 ≤ P ≤ 2.49 × 10(-16)). The significance of haplotype association with D5D activity (P = 2.19 × 10(-17)) was comparable to that of single SNPs, but haplotype association with D6D activity (P = 3.39 × 10(-28)) was much stronger. In a randomized controlled dietary intervention, increasing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) intake significantly increased D5D (P = 4.0 × 10(-9)) and decreased D6D activity (P = 9.16 × 10(-6)) after doses of 0.45, 0.9, and 1.8 g/day for six months. Interaction of rs174537 genotype with treatment was a determinant of D5D activity estimated in plasma (P = 0.05). In conclusion, different sites at the FADS1-FADS2 locus appear to influence D5D and D6D activity, and rs174537 genotype interacts with dietary EPA+DHA to modulate D5D.

Reduction of n-3 PUFAs, specifically DHA and EPA, and enhancement of peroxisomal beta-oxidation in type 2 diabetic rat heart

Background

There is overwhelming evidence that dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs), mainly EPA (C20:5n-3) and DHA (C22:6n-3), has cardiovascular protective effects on patients with type 2 diabetes mellitus (T2DM) but not on healthy people. Because the T2DM heart increases fatty acid oxidation (FAO) to compensate for the diminished utilization of glucose, we hypothesize that T2DM hearts consume more n-3 PUFAs and, therefore, need more n-3 PUFAs. In the present study, we investigated the changes in cardiac n-3 PUFAs and peroxisomal beta-oxidation, which are responsible for the degradation of PUFAs in a high-fat diet (HFD) and low-dose streptozotocin- (STZ) induced type 2 diabetic rat model.

Methods and results

The capillary gas chromatography results showed that all the n-3 (or omega-3) PUFAs, especially DHA (~50%) and EPA (~100%), were significantly decreased, and the n-6/n-3 ratio (~115%) was significantly increased in the hearts of diabetic rats. The activity of peroxisomal beta-oxidation, which is crucial to very-long-chain and unsaturated FA metabolism (including DHA), was significantly elevated in DM hearts. Additionally, the real-time PCR results showed that the mRNA expression of most peroxisomal beta-oxidation key enzymes were up-regulated in T2DM rat hearts, which might contribute to the reduction of n-3 (or omega-3) PUFAs.

Conclusion

In conclusion, our results indicate that T2DM hearts consume more n-3 PUFAs, especially DHA and EPA, due to exaggerated peroxisomal beta-oxidation.

Inhibition of peroxisomal β-oxidation by thioridazine increases the amount of VLCFAs and Aβ generation in the rat brain

Alzheimer's disease (AD) is characterized by the accumulation of the β-amyloid peptide (Aβ), which is generated from sequential cleavages of the amyloid precursor protein (APP) by β-secretase (BACE1) and γ-secretase. Fatty acid alterations in AD brains have recently received substantial attention. Because increased very long chain fatty acid (VLCFA) levels in AD brains imply that peroxisomal β-oxidation dysfunction may be associated with AD pathogenesis, we investigated the effects of impaired peroxisomal β-oxidation on Aβ generation in vivo and in vitro using thioridazine, a selective peroxisomal β-oxidation inhibitor. Under the experimental conditions, thioridazine caused VLCFA accumulation and increases in Aβ(40) content, APP immunoreactivity and APP(751+770) mRNA expressions in the rat cerebral cortex. A correlation analysis showed that the Aβ(40) levels were positively correlated with the cortex C(24:0) and C(26:0) levels. Additionally, the primary cerebral cortex neurons treated with this compound showed increases in APP(751+770) mRNA, APP protein, BACE1 mRNA and protein, and secreted Aβ40 levels. This work supports an emerging viewpoint that impaired peroxisomal function may play an important role in the progression of AD pathology.

Optimized rapeseed oil enriched with healthy micronutrients: a relevant nutritional approach to prevent cardiovascular diseases. Results of the Optim'Oils randomized intervention trial

Rapeseeds are naturally rich in cardioprotective micronutrients but refining leads to substantial losses or the production of undesirable compounds. The Optim'Oils European project proposed innovative refining conditions to produce an optimized rapeseed oil enriched in micronutrients and low in trans linolenic acid. We aimed to investigate cardioprotective properties of this Optimized oil. In a randomized, double-blind, controlled, cross-over study, 59 healthy normolipidaemic men consumed either Optimized or Standard rapeseed oils (20 g/d) and margarines (22 g/d) for 3 weeks. The Optimized oil reduced the trans FA concentration (p=0.009) and increased the contents of alpha-tocopherol (p=0.022) and coenzyme Q10 (p<0.001) in comparison with the Standard oil. Over the 3-week trial, Total-/HDL-cholesterol and LDL-/HDL-cholesterol were increased by 4% (p<0.05) with the Standard oil consumption whereas none of them rose with the Optimized rapeseed oil which increased the HDL-cholesterol and ApoA1 plasma content (+2%, NS and +3%, p<0.05 respectively). The effects observed on the plasma HDL-cholesterol levels (p=0.059), the Total-/HDL-cholesterol ratio (p=0.092), and on the ApoA1 concentrations (p=0.060) suggest an improvement of the cholesterol profile with the Optimized rapeseed oil. Finally, the Optimized oil reduced the plasma content of LDLox (-6%, NS), this effect being significantly different from the Standard oil (p=0.050). In conclusion, reasonable intake of an Optimized rapeseed oil resulting from innovative refining processes and enriched in cardioprotective micronutrients represent a relevant nutritional approach to prevent the risk of cardiovascular diseases by improving the cholesterol profile and reducing LDL oxidation.

Relation between methylmercury exposure and plasma paraoxonase activity in inuit adults from Nunavik

BACKGROUND

Methylmercury (MeHg) exposure has been linked to an increased risk of coronary heart disease (CHD). Paraoxonase 1 (PON1), an enzyme located in the high-density-lipoprotein (HDL) fraction of blood lipids, may protect against CHD by metabolizing toxic oxidized lipids associated with low-density liproprotein and HDL. MeHg has been shown to inhibit PON1 activity in vitro, but this effect has not been studied in human populations.

OBJECTIVES

This study was conducted to determine whether blood mercury levels are linked to decreased plasma PON1 activities in Inuit people who are highly exposed to MeHg through their seafood-based diet.

METHODS

We measured plasma PON1 activity using a fluorogenic substrate and blood concentrations of mercury and selenium by inductively coupled plasma mass spectrometry in 896 Inuit adults. Sociodemographic, anthropometric, clinical, dietary, and lifestyle variables as well as PON1 gene variants (rs705379, rs662, rs854560) were considered as possible confounders or modifiers of the mercury-PON1 relation in multivariate analyses.

RESULTS

In a multiple regression model adjusted for age, HDL cholesterol levels, omega-3 fatty acid content of erythrocyte membranes, and PON1 variants, blood mercury concentrations were inversely associated with PON1 activities [β-coefficient = -0.063; 95% confidence interval (CI), -0.091 to -0.035; p < 0.001], whereas blood selenium concentrations were positively associated with PON1 activities (β-coefficient = 0.067; 95% CI, 0.045-0.088; p < 0.001). We found no interaction between blood mercury levels and PON1 genotypes.

CONCLUSIONS

Our results suggest that MeHg exposure exerts an inhibitory effect on PON1 activity, which seems to be offset by selenium intake.

Long-term effect of an enteral diet with a different n-6/n-3 ratio on fatty acid composition and blood parameters in rats

The n-6/n-3 ratio of polyunsaturated fatty acids (PUFAs) in enteral feeding formulas is not considered to be important, because the short-term administration of these formulas has been the norm for postoperative digestive organs. However, the long-term administration of enteral feeding formulas has been increasingly recommended for patients with aging-associated aphagia. This study is aimed at investigating the effect of the long-term administration of an enteral feeding formula containing n-3 polyunsaturated fatty acids (PUFAs) on the fatty acid composition of endogenous phospholipids. Rats, which were initially fed a diet lacking n-3 PUFAs for 2 generations, were subsequently fed an enteral feeding formula containing or lacking n-3 PUFAs for 12 weeks (n = 10). Then, the fatty acid composition of phospholipids in the brain, liver, red blood cells, and plasma of the rats was analyzed. Although the fatty acid composition of neural tissues is suggested to be not affected by diet, the n-6/n-3 ratio of phospholipids in the brains of rats that were fed an enteral feeding formula containing n-3 PUFAs was significantly lower than those of rats that were fed a formula lacking n-3 PUFAs. The enteral feeding formula containing n-3 PUFAs may be effective for the regulation of brain functions and the prevention of atherosclerosis.

Determinants of AhR-mediated transcriptional activity induced by plasma extracts from Nunavik Inuit adults

The exposure of Inuit people to polychlorinated biphenyls (PCBs) and chlorinated pesticides has been well characterised but little is known regarding their exposure to dioxin-like compounds, which induce toxic effects through binding to the aryl hydrocarbon receptor (AhR). In order to obtain a global measure of persistent organic pollutants in plasma that interact with this signalling pathway, we used a luciferase reporter gene assay to assess the AhR-mediated transcriptional activity elicited by plasma sample extracts from 874 Inuit adults who were recruited in the course of a prospective epidemiological study conducted in Nunavik (Québec, Canada). Several sociodemographic, anthropometric, dietary and lifestyle variables were considered as possible modulating factors of the AhR-mediated activity in multivariate statistical analyses. The geometric mean AhR-mediated activity expressed as 2,3,7,8-tetachlorodibenzo-p-dioxin equivalents was 8.9 pg g(-1) lipids (range: <5-144 pg g(-1) lipids). PCB-153 concentration measured by high-resolution gas chromatography-mass spectrometry was moderately correlated to AhR-mediated activity (Pearson's r=0.53, p<0.001). Multiple linear regression analyses revealed that age and omega-3 fatty acids in erythrocyte membranes (an index of marine food consumption) were positively associated with plasma AhR-mediated activity (p<0.001), whereas a negative association was noted with body fat mass (p=0.037). These results suggest that AhR-mediated transcriptional activity of Inuit plasma extracts is linked to their organochlorine body burden, most likely that of dioxin-like PCBs, polychlorinated dibenzo-p-dioxins and polychlorodibenzofurans. AhR-mediated transcriptional activity measures may prove useful in investigating possible associations between exposure to AhR agonists and adverse health effects in this indigenous population.

A Western-like fat diet is sufficient to induce a gradual enhancement in fat mass over generations

The prevalence of obesity has steadily increased over the last few decades. During this time, populations of industrialized countries have been exposed to diets rich in fat with a high content of linoleic acid and a low content of alpha-linolenic acid compared with recommended intake. To assess the contribution of dietary fatty acids, male and female mice fed a high-fat diet (35% energy as fat, linoleic acid:alpha-linolenic acid ratio of 28) were mated randomly and maintained after breeding on the same diet for successive generations. Offspring showed, over four generations, a gradual enhancement in fat mass due to combined hyperplasia and hypertrophy with no change in food intake. Transgenerational alterations in adipokine levels were accompanied by hyperinsulinemia. Gene expression analyses of the stromal vascular fraction of adipose tissue, over generations, revealed discrete and steady changes in certain important players, such as CSF3 and Nocturnin. Thus, under conditions of genome stability and with no change in the regimen over four generations, we show that a Western-like fat diet induces a gradual fat mass enhancement, in accordance with the increasing prevalence of obesity observed in humans.

A high-fat diet induces lower expression of retinoid receptors and their target genes GAP-43/neuromodulin and RC3/neurogranin in the rat brain

Numerous studies have reported an association between cognitive impairment in old age and nutritional factors, including dietary fat. Retinoic acid (RA) plays a central role in the maintenance of cognitive processes via its nuclear receptors (NR), retinoic acid receptor (RAR) and retinoid X receptor (RXR), and the control of target genes, e.g. the synaptic plasticity markers GAP-43/neuromodulin and RC3/neurogranin. Given the relationship between RA and the fatty acid signalling pathways mediated by their respective NR (RAR/RXR and PPAR), we investigated the effect of a high-fat diet (HFD) on (1) PUFA status in the plasma and brain, and (2) the expression of RA and fatty acid NR (RARbeta, RXRbetagamma and PPARdelta), and synaptic plasticity genes (GAP-43 and RC3), in young male Wistar rats. In the striatum of rats given a HFD for 8 weeks, real-time PCR (RT-PCR) revealed a decrease in mRNA levels of RARbeta ( - 14 %) and PPARdelta ( - 13 %) along with an increase in RXRbetagamma (+52 %). Concomitantly, RT-PCR and Western blot analysis revealed (1) a clear reduction in striatal mRNA and protein levels of RC3 ( - 24 and - 26 %, respectively) and GAP-43 ( - 10 and - 42 %, respectively), which was confirmed by in situ hybridisation, and (2) decreased hippocampal RC3 and GAP-43 protein levels (approximately 25 %). Additionally, HFD rats exhibited a significant decrease in plasma ( - 59 %) and brain ( - 6 %) n-3 PUFA content, mainly due to the loss of DHA. These results suggest that dietary fat induces neurobiological alterations by modulating the brain RA signalling pathway and n-3 PUFA content, which have been previously correlated with cognitive impairment.

Refrigerator storage of expressed human milk in the neonatal intensive care unit

OBJECTIVE

To provide recommendations for refrigerator storage of human milk, the overall integrity (bacterial growth, cell counts, and component concentrations) of milk was examined during 96 hours of storage at 4 degrees C.

STUDY DESIGN

Fresh milk samples (n = 36) were divided and stored at 4 degrees C for 0, 24, 48, 72, and 96 hours. At each time, pH, white cell count, and osmolality were measured and additional samples were stored at -80 degrees C until analyzed for bacteria and concentrations of lactoferrin, secretory (s)IgA, fat, fatty acids, and protein.

RESULTS

There were no significant changes for osmolality, total and Gram-negative bacterial colony counts or concentrations of sIgA, lactoferrin, and fat. Gram-positive colony counts (2.9 to 1.6 x 10(5) colony-forming units per mL), pH (7.21 to 6.68), white blood cell counts (2.31 to 1.85 x 10(6) cells per mL), and total protein (17.5 to 16.7 g/L) declined, and free fatty acid concentrations increased (0.35 to 1.28 g/L) as storage duration increased, P < .001.

CONCLUSIONS

Changes were minimal and the overall integrity of milk during refrigerator storage was preserved. Fresh mother's milk may be stored at refrigerator temperature for as long as 96 hours.

Administration of dietary fish oil capsules in healthy middle-aged Japanese men with a high level of fish consumption

The nutritional effects of fish oil, which is rich in the n-3 polyunsaturated fatty acids, have been reported. In this randomized, placebo-controlled, double-blind, crossover study, we evaluated the effects of dietary fish oil capsules on the hematological parameters of healthy middle-aged Japanese men with a high level of fish oil consumption. Over a 4-week period, subjects were administered five fish oil or olive oil (placebo) capsules with every meal (1,260 mg eicosapentaenoic acid and 540 mg docosahexaenoic acid/day). There was a 4-week washout period between the treatment phases. The results did not demonstrate a decrease in plasma triacylglycerol, cholesterol, low-density lipoprotein cholesterol, and whole-blood viscosity. Further, no changes in the fatty acid composition of plasma and erythrocyte phospholipids were noted. These results suggested that the supplementation of fish oil might be effective only for those subjects who have a lower level of fish oil consumption.

Analysis of composition and structure of Clostridium thermocellum membranes from wild-type and ethanol-adapted strains

Clostridium thermocellum is a candidate organism for consolidated bioprocessing of lignocellulosic biomass into ethanol. However, commercial use is limited due to growth inhibition at modest ethanol concentrations. Recently, an ethanol-adapted strain of C. thermocellum was produced. Since ethanol adaptation in microorganisms has been linked to modification of membrane lipids, we tested the hypothesis that ethanol adaptation in C. thermocellum involves lipid modification by comparing the fatty acid composition and membrane anisotropy of wild-type and ethanol-adapted strains. Derivatization to fatty acid methyl esters provided quantitative lipid analysis. Compared to wild-type, the ethanol-adapted strain had a larger percentage of fatty acids with chain lengths >16:0 and showed a significant increase in the percentage of 16:0 plasmalogens. Structural identification of fatty acids was confirmed through mass spectral fragmentation patterns of picolinyl esters. Ethanol adaptation did not involve modification at sites of methyl branching or the unsaturation index. Comparison of steady-state fluorescence anisotropy experiments, in the absence and presence of ethanol, provided evidence for the effects of ethanol on membrane fluidity. In the presence of ethanol, both strains displayed increased fluidity by approximately 12%. These data support the model that ethanol adaptation was the result of fatty acid changes that increased membrane rigidity that counter-acted the fluidizing effect of ethanol.

Increased myocardial susceptibility to repetitive ischemia with high-fat diet-induced obesity

Obesity and diabetes are frequently associated with cardiovascular disease. When a normal heart is subjected to brief/sublethal repetitive ischemia and reperfusion (I/R), adaptive responses are activated to preserve cardiac structure and function. These responses include but are not limited to alterations in cardiac metabolism, reduced calcium responsiveness, and induction of antioxidant enzymes. In a model of ischemic cardiomyopathy inducible by brief repetitive I/R, we hypothesized that dysregulation of these adaptive responses in diet-induced obese (DIO) mice would contribute to enhanced myocardial injury. DIO C57BL/6J mice were subjected to 15 min of daily repetitive I/R while under short-acting anesthesia, a protocol that results in the development of fibrotic cardiomyopathy. Cardiac lipids and candidate gene expression were analyzed at 3 days, and histology at 5 days of repetitive I/R. Total free fatty acids (FFAs) in the cardiac extracts of DIO mice were significantly elevated, reflecting primarily the dietary fatty acid (FA) composition. Compared with lean controls, cardiac FA oxidation (FAO) capacity of DIO mice was significantly higher, concurrent with increased expression of FA metabolism gene transcripts. Following 15 min of daily repetitive I/R for 3 or 5 days, DIO mice exhibited increased susceptibility to I/R and, in contrast to lean mice, developed microinfarction, which was associated with an exaggerated inflammatory response. Repetitive I/R in DIO mice was associated with more profound significant downregulation of FA metabolism gene transcripts and elevated FFAs and triglycerides. Maladaptive metabolic changes of FA metabolism contribute to enhanced myocardial injury in diet-induced obesity.

Docosahexaenoic acid disrupts in vitro amyloid beta(1-40) fibrillation and concomitantly inhibits amyloid levels in cerebral cortex of Alzheimer's disease model rats

We have previously reported that dietary docosahexaenoic acid (DHA) improves and/or protects against impairment of cognition ability in amyloid beta(1-40) (Abeta(1-40))-infused Alzheimer's disease (AD)-model rats. Here, after the administration of DHA to AD model rats for 12 weeks, the levels of Abeta(1-40), cholesterol and the composition of fatty acids were investigated in the Triton X100-insoluble membrane fractions of their cerebral cortex. The effects of DHA on the in vitro formation and kinetics of fibrillation of Abeta(1-40) were also investigated by thioflavin T fluorescence spectroscopy, transmission electron microscopy and fluorescence microscopy. Dietary DHA significantly decreased the levels of Abeta(1-40), cholesterol and saturated fatty acids in the detergent insoluble membrane fractions of AD rats. The formation of Abeta fibrils was also attenuated by their incubation with DHA, as demonstrated by the decreased intensity of thioflavin T-derived fluorescence and by electron micrography. DHA treatment also decreased the intensity of thioflavin fluorescence in preformed-fibril Abeta peptides, demonstrating the anti-amyloidogenic effects of DHA. We then investigated the effects of DHA on the levels of oligomeric amyloid that is generated during its in vitro transformation from monomers to fibrils, by an anti-oligomer-specific antibody and non-reducing Tris-Glycine gradient (4-20%) gel electrophoresis. DHA concentration-dependently reduced the levels of oligomeric amyloid species, suggesting that dietary DHA-induced suppression of in vivo Abeta(1-40) aggregation occurs through the inhibitory effect of DHA on oligomeric amyloid species.

New method for GC/FID and GC-C-IRMS analysis of plasma free fatty acid concentration and isotopic enrichment

A simple, direct and accurate method for the determination of concentration and enrichment of free fatty acids (FFAs) in human plasma was developed. The validation and comparison to a conventional method are reported. Three amide derivatives, dimethyl, diethyl and pyrrolidide, were investigated in order to achieve optimal resolution of the individual fatty acids. This method involves the use of dimethylamine/Deoxo-Fluor to derivatize plasma free fatty acids to their dimethylamides. This derivatization method is very mild and efficient, and is selective only towards FFAs so that no separation from a total lipid extract is required. The direct method gave lower concentrations for palmitic acid and stearic acid and increased concentrations for oleic acid and linoleic acid in plasma as compared to methyl ester derivative after thin-layer chromatography. The [(13)C]palmitate isotope enrichment measured using direct method was significantly higher than that observed with the BF(3)/MeOH-TLC method. The present method provided accurate and precise measures of concentration as well as enrichment when analyzed with gas chromatography combustion-isotope ratio-mass spectrometry.

The acute effects of differential dietary fatty acids on human skeletal muscle pyruvate dehydrogenase activity

Pyruvate dehydrogenase (PDH) is an important regulator of carbohydrate oxidation during exercise, and its activity can be downregulated by an increase in dietary fat. The purpose of this study was to determine the acute metabolic effects of differential dietary fatty acids on the activation of the PDH complex (PDHa activity) at rest and at the onset of moderate-intensity exercise. University-aged male subjects (n = 7) underwent two fat-loading trials spaced at least 2 wk apart. Subjects consumed approximately 300 g saturated (SFA) or n-6 polyunsaturated fatty acid (PUFA) fat over the course of 5 h. Following this, participants cycled at 65% of their maximum oxygen uptake for 15 min. Muscle biopsies were taken before and following fat loading and at 1 min exercise. Plasma free fatty acids increased from 0.15 +/- 0.07 to 0.54 +/- 0.19 mM over 5 h with SFA and from 0.11 +/- 0.04 to 0.35 +/- 0.13 mM with n-6 PUFA and were significantly lower throughout the n-6 PUFA trial. PDHa activity was unchanged following fat loading but increased at the onset of exercise in the SFA trial, from 1.18 +/- 0.27 to 2.16 +/- 0.37 mmol x min(-1) x kg wet wt(-1). This effect was negated in the n-6 PUFA trial (1.04 +/- 0.20 to 1.28 +/- 0.36 mmol x min(-1) x kg wet wt(-1)). PDH kinase was unchanged in both trials, suggesting that the attenuation of PDHa activity with n-6 PUFA was a result of changes in the concentrations of intramitochondrial effectors, potentially intramitochondrial NADH or Ca(2+). Our findings suggest that attenuated PDHa activity contributes to the preferential oxidation of n-6 PUFA during moderate-intensity exercise.

Pro-apoptotic low-density lipoprotein subfractions in type II diabetes

OBJECTIVE

To test the hypothesis that differences in subfractions of circulating lipoproteins between diabetic and non-diabetic subjects exist and might contribute to the increased risk for atherosclerosis in type II diabetics.

METHODS AND RESULTS

LDL isolated from diabetic (D) and control subjects (N) were separated by FPLC into five subfractions (L1-L5). The fractional distributions of N- and D-LDL were not different, but the most strongly retained subfractions of D-LDL (D-L5) were markedly more pro-apoptotic to bovine aortic endothelial cells in vitro than were the other subfractions in D- or N-LDL. D-L5 induced time- and concentration-dependent apoptosis that was inhibited by z-VAD-fmk. The most electronegative D-LDL subfractions contained substantial amounts of apoproteins AI, E and CIII, higher concentrations of non-esterified fatty acids and LpPLA2, and lower trinitrobenzenesulfonic acid (TNBSA) reactivities. Electronegative subfractions of D-LDL exhibited longer lag times and lower net increases in absorbance at 234 nm with Cu-catalyzed oxidation in vitro.

CONCLUSIONS

The toxicities of electronegative subfractions of LDL from diabetic subjects to endothelial cells in vitro may be pivotal to vascular complications of diabetes in vivo, but the specific molecular alterations responsible for the toxicities of these subfractions of diabetic LDL are not known.

n-3 Fatty acid supplementation and regular moderate exercise: differential effects of a combined intervention on neutrophil function

CVD is associated with a cellular inflammatory/immune response.n-3 PUFA and moderate aerobic exercise independently alter cytokine production and leucocyte function. There is limited evidence for the combined effect of these treatments on immune function, particularly in patients with risk factors for CVD. We hypothesised that exercise would enhance the anti-inflammatory effects ofn-3 PUFA. In a randomised, placebo-controlled study, fifty volunteers were allocated double-blind to consume either sunflower oil (6 g/d, placebo) or DHA-rich fish oil (6 g/d; about 2 gn-3 PUFA; 1·6 g DHA /d) for 12 weeks. Volunteers were further randomised to undertake regular exercise (walking 3 d/week for 45 min at 75 % of maximum heart rate) or maintain their usual physical activity for 12 weeks. Immune functions were assessed in blood taken initially and after 12 weeks. There was no effect on cytokine production by T cells and monocytes. Superoxide anion production from stimulated blood neutrophils was decreased by fish oil (19·5 (sem8·5) %,P = 0·016) but not by exercise, and this change was negatively correlated with the incorporation of DHA into erythrocytes (r–0·385,P = 0·047). Participation in regular exercise maintained neutrophil bactericidal activity, which decreased in non-exercising subjects (2·9 (sem0·7) %,P = 0·013). Neutrophil chemotaxis and adherence were not significantly affected by exercise, oil, or the combination of the two. Thus the combination of moderate exercise and fish-oil supplementation, which reduces cardiovascular risk, may also help to counteract inflammation.