The Catechins Profile of Green Tea Extracts Affects the Antioxidant Activity and Degradation of Catechins in DHA-Rich Oil.

This study investigated the effect of the catechins profile on the antioxidant activity of green tea extracts (GTEs) by comparing the antioxidant activity of an EGC-rich GTE (GTE1, catechin content: 58% EGC, 30.1% EGCG, 7.9% EC, and 3.9% ECG) and an EGCG-rich GTE (GTE2, catechin content: 60.6% EGCG, 17.7% EGC, 11.8% ECG, and 9.8% EC) in a DHA-rich oil. The effects of the individual catechins (EGC, EC, EGCG, and ECG) and reconstituted catechins mixtures (CatMix), prepared to contain the same amount of major catechins as in the GTEs, were also measured. All treatments (GTE1, CatMix1, GTE2, CatMix2, EGC250, EC250, EGCG250, and ECG250), each containing epistructured catechins at a concentration of 250 ppm, as well as the control (oil with no added antioxidant), were stored at 30 °C for 21 days with sampling intervals of 7 days. The antioxidant activity was assessed by measuring the peroxide value (PV) and p-anisidine value (p-AV) of oils. Changes in fatty acid content and catechins content were also monitored. Both GTEs enhanced the oxidative stability of the DHA-rich oil, but GTE1 demonstrated a stronger antioxidant activity than GTE2. No significant difference was observed between the PV of treatments with GTE1 and CatMix1 during storage, whereas the PV of oil with GTE2 was significantly higher than that with CatMix2 after 21 days. Among the individual catechins, EGC was the strongest antioxidant. Overall, the antioxidant activities of the extracts and catechins were observed in the decreasing order GTE1 ≈ EGC250 ≈ CatMix1 > GTE2 > EGCG250 ≈ CatMix2 > ECG250 > EC250. A significant change in fatty acid content was observed for the control and EC250 samples, and the catechins were most stable in GTE1-supplemented oil. Our results indicate that the EGC-rich GTE is a more potent antioxidant in DHA-rich oil than the EGCG-rich GTE.

Contribution of Membrane Vesicle to Reprogramming of Bacterial Membrane Fluidity in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic pathogen capable of resisting environmental insults by applying various strategies, including regulating membrane fluidity and producing membrane vesicles (MVs). This study examined the difference in membrane fluidity between planktonic and biofilm modes of growth in P. aeruginosa and whether the ability to alter membrane rigidity in P. aeruginosa could be transferred via MVs. To this end, planktonic and biofilm P. aeruginosa were compared with respect to the lipid composition of their membranes and their MVs and the expression of genes contributing to alteration of membrane fluidity. Additionally, viscosity maps of the bacterial membrane in planktonic and biofilm lifestyles and under the effect of incubation with bacterial MVs were obtained. Further, the growth rate and biofilm formation capability of P. aeruginosa in the presence of MVs were compared. Results showed that the membrane of the biofilm bacteria is significantly less fluid than the membrane of the planktonic bacteria and is enriched with saturated fatty acids. Moreover, the enzymes involved in altering the structure of existing lipids and favoring membrane rigidification are overexpressed in the biofilm bacteria. MVs of biofilm P. aeruginosa elicit membrane rigidification and delay the bacterial growth in the planktonic lifestyle; conversely, they enhance biofilm development in P. aeruginosa. Overall, the study describes the interplay between the planktonic and biofilm bacteria by shedding light on the role of MVs in altering membrane fluidity. IMPORTANCE Membrane rigidification is a survival strategy in Pseudomonas aeruginosa exposed to stress. Despite various studies dedicated to the mechanism behind this phenomenon, not much attention has been paid to the contribution of the bacterial membrane vesicles (MVs) in this regard. This study revealed that P. aeruginosa rigidifies its membrane in the biofilm mode of growth. Additionally, the capability of decreasing membrane fluidity is transferable to the bacterial population via the bacterial MVs, resulting in reprogramming of bacterial membrane fluidity. Given the importance of membrane rigidification for decreasing the pathogen's susceptibility to antimicrobials, elucidation of the conditions leading to such biophysicochemical modulation of the P. aeruginosa membrane should be considered for the purpose of developing therapeutic approaches against this resistant pathogen.

Green Synthesis of Iron-Doped Cobalt Oxide Nanoparticles from Palm Kernel Oil via Co-Precipitation and Structural Characterization.

In this study, a bio-derived precipitating agent/ligand, palm kernel oil, has been used as an alternative route for the green synthesis of nanoparticles of Fe-doped Co3O4 via the co-precipitation reaction. The palm oil was extracted from dried palm kernel seeds by crushing, squeezing and filtration. The reaction of the palm kernel oil with potassium hydroxide, under reflux, yielded a solution containing a mixture of potassium carboxylate and excess hydroxide ions, irrespective of the length of saponification. The as-obtained solution reacts with an aqueous solution containing iron and cobalt ions to yield the desired metallo-organic precursor, iron cobalt carboxylate. Characterization of the precursors by IR and gas chromatography (GC) attests to the presence of carboxylate fatty acids in good agreement with the proportion contained in the oil, and ICP confirms that the metallic ratios are in the proportion used during the synthesis. Analysis of the products thermally decomposed between 400 °C and 600 °C by XRD, EDX, TEM and ToF-SIMS, established that cobalt iron oxide nanoparticles (Co(1-x)Fex)3O4 were obtained for x ≤ 0.2 and a nanocomposite material (Co(1-x)Fex)3O4/Fe3O4 for x ≥ 0.2, with sizes between 22 and 9 nm. ToF-SIMS and XRD provided direct evidence of the progressive substitution of cobalt by iron in the Co3O4 crystal structure for x ≤ 0.2.

Punicic Acid Triggers Ferroptotic Cell Death in Carcinoma Cells.

Plant-derived conjugated linolenic acids (CLnA) have been widely studied for their preventive and therapeutic properties against diverse diseases such as cancer. In particular, punicic acid (PunA), a conjugated linolenic acid isomer (C18:3 c9t11c13) present at up to 83% in pomegranate seed oil, has been shown to exert anti-cancer effects, although the mechanism behind its cytotoxicity remains unclear. Ferroptosis, a cell death triggered by an overwhelming accumulation of lipid peroxides, has recently arisen as a potential mechanism underlying CLnA cytotoxicity. In the present study, we show that PunA is highly cytotoxic to HCT-116 colorectal and FaDu hypopharyngeal carcinoma cells grown either in monolayers or as three-dimensional spheroids. Moreover, our data indicate that PunA triggers ferroptosis in carcinoma cells. It induces significant lipid peroxidation and its effects are prevented by the addition of ferroptosis inhibitors. A combination with docosahexaenoic acid (DHA), a known polyunsaturated fatty acid with anticancer properties, synergistically increases PunA cytotoxicity. Our findings highlight the potential of using PunA as a ferroptosis-sensitizing phytochemical for the prevention and treatment of cancer.

Green Tea Extract Enhances the Oxidative Stability of DHA-Rich Oil.

Docosahexaenoic acid (DHA) is one of the most important omega-3 polyunsaturated fatty acids, with proven health-promoting properties. However, oils with a very high content in DHA (DHAO) are extremely susceptible to oxidation, which affects shelf stability and limits incorporation in food products. Green tea extracts (GTE) are potential candidates for the protection of these oils, but their use in such oils has not been previously reported. This study investigated the effect of GTE (160 ppm, 400 ppm, 1000 ppm) and α-tocopherol (80 ppm, 200 ppm, 500 ppm) on the oxidative stability of a DHAO over a 9-week storage at 30 °C. The oxidative status was monitored during storage by the measurement of peroxide value (PV) and p-anisidine value (p-AV). Changes in eicosapentaenoic acid (EPA) and DHA content, as well as in catechins and tocopherol contents, were also evaluated. The addition of GTE enhanced the oxidative stability of DHAO by reducing the formation of peroxides and secondary oxidation products, whereas α-tocopherol had no significant effect on the PV of oil during storage but led to a significantly higher p-AV. The EPA and DHA content of DHAO was stable in GTE-supplemented samples whereas a decrease was observed in the control and α-tocopherol-supplemented samples. GTE also delayed the degradation of tocopherols initially present in the oil, while catechins resulting from the addition of GTE decreased progressively during the storage period.

Peroxidation of n-3 and n-6 polyunsaturated fatty acids in the acidic tumor environment leads to ferroptosis-mediated anticancer effects.

Tumor acidosis promotes disease progression through a stimulation of fatty acid (FA) metabolism in cancer cells. Instead of blocking the use of FAs by acidic cancer cells, we examined whether excess uptake of specific FAs could lead to antitumor effects. We found that n-3 but also remarkably n-6 polyunsaturated FA (PUFA) selectively induced ferroptosis in cancer cells under ambient acidosis. Upon exceeding buffering capacity of triglyceride storage into lipid droplets, n-3 and n-6 PUFA peroxidation led to cytotoxic effects in proportion to the number of double bonds and even more so in the presence of diacylglycerol acyltransferase inhibitors (DGATi). Finally, an n-3 long-chain PUFA-rich diet significantly delayed mouse tumor growth when compared with a monounsaturated FA-rich diet, an effect further accentuated by administration of DGATi or ferroptosis inducers. These data point out dietary PUFA as a selective adjuvant antitumor modality that may efficiently complement pharmacological approaches.

The Egg Yolk Content in ω-3 and Conjugated Fatty Acids Can Be Sustainably Increased upon Long-Term Feeding of Laying Hens with a Diet Containing Flaxseeds and Pomegranate Seed Oil.

Long-term feeding trials examining the incorporation of conjugated linolenic acids (CLnA) into the diet of laying hens are lacking. In the present study, we compared two diets in sixty-six red Sex-Link hens (33 hens/treatment), fed for 26 weeks. The control diet was high in oleic acid, while the test diet was high in α-linolenic acid (ALA) and punicic acid (PunA). No significant differences were observed between treatments for hens' performance, egg weight and yolk weight. In contrast, dietary ALA and PunA resulted in a significant increase in n-3 PUFA, rumenic acid (RmA) and PunA contents in egg yolk, as well as in the liver, heart, muscle and adipose tissue of the hens. Other conjugated dienes resulting from the metabolism of PunA or RmA also accumulated in the egg yolk and tissues. Unlike DHA, which was exclusively distributed in phospholipids, ALA, RmA and PunA were preferably distributed in triglycerides.

Impaired Cytoskeletal and Membrane Biophysical Properties of Acanthocytes in Hypobetalipoproteinemia - A Case Study.

Familial hypobetalipoproteinemia is a metabolic disorder mainly caused by mutations in the apolipoprotein B gene. In its homozygous form it can lead without treatment to severe ophthalmological and neurological manifestations. In contrast, the heterozygous form is generally asymptomatic but associated with a low risk of cardiovascular disease. Acanthocytes or thorny red blood cells (RBCs) are described for both forms of the disease. However, those morphological changes are poorly characterized and their potential consequences for RBC functionality are not understood. Thus, in the present study, we asked whether, to what extent and how acanthocytes from a patient with heterozygous familial hypobetalipoproteinemia could exhibit altered RBC functionality. Acanthocytes represented 50% of the total RBC population and contained mitoTracker-positive surface patches, indicating the presence of mitochondrial fragments. While RBC osmotic fragility, calcium content and ATP homeostasis were preserved, a slight decrease of RBC deformability combined with an increase of intracellular free reactive oxygen species were observed. The spectrin cytoskeleton was altered, showing a lower density and an enrichment in patches. At the membrane level, no obvious modification of the RBC membrane fatty acids nor of the cholesterol content were detected but the ceramide species were all increased. Membrane stiffness and curvature were also increased whereas transversal asymmetry was preserved. In contrast, lateral asymmetry was highly impaired showing: (i) increased abundance and decreased functionality of sphingomyelin-enriched domains; (ii) cholesterol enrichment in spicules; and (iii) ceramide enrichment in patches. We propose that oxidative stress induces cytoskeletal alterations, leading to increased membrane stiffness and curvature and impaired lipid lateral distribution in domains and spicules. In addition, ceramide- and spectrin-enriched patches could result from a RBC maturation defect. Altogether, the data indicate that acanthocytes are associated with cytoskeletal and membrane lipid lateral asymmetry alterations, while deformability is only mildly impaired. In addition, familial hypobetalipoproteinemia might also affect RBC precursors leading to disturbed RBC maturation. This study paves the way for the potential use of membrane biophysics and lipid vital imaging as new methods for diagnosis of RBC disorders.

A Three-Month Consumption of Eggs Enriched with ω-3, ω-5 and ω-7 Polyunsaturated Fatty Acids Significantly Decreases the Waist Circumference of Subjects at Risk of Developing Metabolic Syndrome: A Double-Blind Randomized Controlled Trial.

Alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA), and punicic acid (PunA) are claimed to influence several physiological functions including insulin sensitivity, lipid metabolism and inflammatory processes. In this double-blind randomized controlled trial, we investigated the combined effect of ALA, DHA, RmA and PunA on subjects at risk of developing metabolic syndrome. Twenty-four women and men were randomly assigned to two groups. Each day, they consumed two eggs enriched with oleic acid (control group) or enriched with ALA, DHA, RmA, and PunA (test group) for 3 months. The waist circumference decreased significantly (-3.17 cm; p < 0.001) in the test group. There were no major changes in plasma insulin and blood glucose in the two groups. The dietary treatments had no significant effect on endothelial function as measured by peripheral arterial tonometry, although erythrocyte nitrosylated hemoglobin concentrations tended to decrease. The high consumption of eggs induced significant elevations in plasma low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol (p < 0.001), which did not result in any change in the LDL/HDL ratio in both groups. These results indicate that consumption of eggs enriched with ALA, DHA, RmA and PunA resulted in favorable changes in abdominal obesity without affecting other factors of the metabolic syndrome.

Interplay Between Plasma Membrane Lipid Alteration, Oxidative Stress and Calcium-Based Mechanism for Extracellular Vesicle Biogenesis From Erythrocytes During Blood Storage.

The shedding of extracellular vesicles (EVs) from the red blood cell (RBC) surface is observed during senescence in vivo and RBC storage in vitro. Two main models for EV shedding, respectively based on calcium rise and oxidative stress, have been proposed in the literature but the role of the plasma membrane lipid composition and properties is not understood. Using blood in K+/EDTA tubes stored for up to 4 weeks at 4°C as a relevant RBC vesiculation model, we showed here that the RBC plasma membrane lipid composition, organization in domains and biophysical properties were progressively modified during storage and contributed to the RBC vesiculation. First, the membrane content in cholesterol and linoleic acid decreased whereas lipid peroxidation and spectrin:membrane occupancy increased, all compatible with higher membrane rigidity. Second, phosphatidylserine surface exposure showed a first rapid rise due to membrane cholesterol decrease, followed by a second calcium-dependent increase. Third, lipid domains mainly enriched in GM1 or sphingomyelin strongly increased from the 1st week while those mainly enriched in cholesterol or ceramide decreased during the 1st and 4th week, respectively. Fourth, the plasmatic acid sphingomyelinase activity considerably increased upon storage following the sphingomyelin-enriched domain rise and potentially inducing the loss of ceramide-enriched domains. Fifth, in support of the shedding of cholesterol- and ceramide-enriched domains from the RBC surface, the number of cholesterol-enriched domains lost and the abundance of EVs released during the 1st week perfectly matched. Moreover, RBC-derived EVs were enriched in ceramide at the 4th week but depleted in sphingomyelin. Then, using K+/EDTA tubes supplemented with glucose to longer preserve the ATP content, we better defined the sequence of events. Altogether, we showed that EV shedding from lipid domains only represents part of the global vesiculation mechanistics, for which we propose four successive events (cholesterol domain decrease, oxidative stress, sphingomyelin/sphingomyelinase/ceramide/calcium alteration and phosphatidylserine exposure).

Growth performance and immune status in common carp Cyprinus carpio as affected by plant oil-based diets complemented with ß-glucan.

Omnivorous fish species such as the common carp (Cyprinus carpio) are able to biosynthesise long chain polyunsaturated fatty acids (LC-PUFAs) from plant oil PUFA precursors, but the influence of the amount and quality of the LC-PUFAs biosynthesised from these oils on the immunocompetence status of the fish has received little attention. This study aims to evaluate whether the conversion of PUFA by carp induces a sufficient biosynthesis of LC-PUFA to maintain a good immunocompetence status in this species. Six iso-nitrogenous (crude protein = 39.1%) and iso-lipidic (crude lipids = 10%) diets containing three different lipid sources (cod liver oil (CLO) as fish oil; linseed oil (LO) and sunflower oil (SFO) as plant oils) were formulated with or without ß-glucan supplementation at 0.25 g/kg diet. Juvenile carp (16.3 ±â€¯0.6 g initial body weight) were fed a daily ration of 4% body weight for 9 weeks and then infected at day 64 with the bacteria Aeromonas hydrophyla. No significant differences in survival rate, final body weight, specific growth rate and feed conversion rate were observed between diets. After bacterial infection, mortality rate did not differ between fish fed CLO and plant oil-based diets, indicating that the latter oils did not affect the overall immunocompetence status of common carp. Plant oil-based diets did not alter lysozyme activity in healthy and infected fish. No negative effects of plant oils on complement activity (ACH50) were observed in healthy fish, even if both plant oil-based diets induced a decrease in stimulated fish two days after infection. Furthermore, the levels of various immune genes (nk, lys, il-8, pla, pge, alox) were not affected by plant oil-based diets. The expression of pla and pge genes were higher in SFO-fed fish than in CLO ones, indicating that this plant oil rich in linoleic acid (LA) better stimulated the eicosanoid metabolism process than fish oil. In response to ß-glucan supplementation, some innate immune functions seemed differentially affected by plant oil-based diets. LO and SFO induced substantial LC-PUFA production, even if fish fed CLO displayed the highest EPA and DHA levels in tissues. SFO rich in LA induced the highest ARA levels in fish muscle while LO rich in α-linolenic acid (ALA) sustained higher EPA production than SFO. A significantly higher fads-6a expression level was observed in SFO fish than in LO ones, but this was not observed for elovl5 expression. In conclusion, the results show that common carp fed plant oil-based diets are able to produce substantial amounts of LC-PUFA for sustaining growth rate, immune status and disease resistance similar to fish fed a fish oil-based diet. The differences in the production capacity of LC-PUFAs by the two plant oil-based diets were associated to a differential activation of some immune pathways, explaining how the use of these oils did not affect the overall immunocompetence of fish challenged with bacterial infection. Moreover, plant oil-based diets did not induce substantial negative effects on the immunomodulatory action of ß-glucans, confirming that these oils are suitable for sustaining a good immunocompetence status in common carp.

High hydrostatic pressure influences the in vitro response to xenobiotics in Dicentrarchus labrax liver.

Hydrostatic pressure (HP) increases by about 1 atmosphere (0.1MPa) for each ten-meter depth increase in the water column. This thermodynamical parameter could well influence the response to and effects of xenobiotics in the deep-sea biota, but this possibility remains largely overlooked. To grasp the extent of HP adaptation in deep-sea fish, comparative studies with living cells of surface species exposed to chemicals at high HP are required. We initially conducted experiments with precision-cut liver slices of a deep-sea fish (Coryphaenoides rupestris), co-exposed for 15h to the aryl hydrocarbon receptor (AhR) agonist 3-methylcholanthrene at HP levels representative of the surface (0.1MPa) and deep-sea (5-15MPa; i.e., 500-1500m depth) environments. The transcript levels of a suite of stress-responsive genes, such as the AhR battery CYP1A, were subsequently measured (Lemaire et al., 2012; Environ. Sci. Technol. 46, 10310-10316). Strikingly, the AhR agonist-mediated increase of CYP1A mRNA content was pressure-dependently reduced in C. rupestris. Here, the same co-exposure scenario was applied for 6 or 15h to liver slices of a surface fish, Dicentrarchus labrax, a coastal species presumably not adapted to high HP. Precision-cut liver slices of D. labrax were also used in 1h co-exposure studies with the pro-oxidant tert-butylhydroperoxide (tBHP) as to investigate the pressure-dependence of the oxidative stress response (i.e., reactive oxygen production, glutathione and lipid peroxidation status). Liver cells remained viable in all experiments (adenosine triphosphate content). High HP precluded the AhR agonist-mediated increase of CYP1A mRNA expression in D. labrax, as well as that of glutathione peroxidase, and significantly reduced that of heat shock protein 70. High HP (1h) also tended per se to increase the level of oxidative stress in liver cells of the surface fish. Trends to an increased resistance to tBHP were also noted. Whether the latter observation truly reflects a protective response to oxidative stress will be addressed in future co-exposure studies with both surface and deep-sea fish liver cells, using additional pro-oxidant chemicals. Altogether, data on CYP1A inducibility with D. labrax and C. rupestris support the view that high HP represses AhR signaling in marine fishes, and that only species adapted to thrive in the deep-sea have evolved the molecular adaptations necessary to counteract to some extent this inhibition.

Nutritional composition and antioxidant properties of the sim fruit (Rhodomyrtus tomentosa).

In this study, detailed chemical properties of sim (Rhodomyrtus tomentosa (Ait.) Hassk.) fruit including nutritional composition, phenolic content and antioxidant capacity were determined for the first time. A 150g serving of sim fruit contained high levels of dietary fibre (69.94-87.43% of Recommended Daily Intake (RDI)), α-tocopherol (38.90-51.87% RDI), manganese (>100% RDI), and copper (44.44% RDI) but low levels of protein (2.63% RDI), lipid (1.59-3.5% RDI), and sugars (5.65% RDI). The predominant fatty acid in the sim fruit sample was linoleic acid (75.36% of total fatty acids). Interestingly, total phenolics (49.21±0.35mg gallic acid equivalent (GAE)/g dry weight (DW)) were particularly high and resulted in a high antioxidant capacity (431.17±14.56µmol Trolox equivalent (TE)/g DW). These results, together with our recent discovery of high amount of piceatannol, a stilbene with potent biological activities, highlight the potential of sim, an under-utilised plant species from South-East Asia, as a new source of health-promoting compounds including dietary fibres, essential fatty acids, and phenolic compounds.

PCB-153 shows different dynamics of mobilisation from differentiated rat adipocytes during lipolysis in comparison with PCB-28 and PCB-118.

BACKGROUND: Polychlorinated biphenyls (PCBs) are persistent organic pollutants. Due to their lipophilic character, they are preferentially stored within the adipose tissue. During the mobilisation of lipids, PCBs might be released from adipocytes into the bloodstream. However, the mechanisms associated with the release of PCBs have been poorly studied. Several in vivo studies followed their dynamics of release but the complexity of the in vivo situation, which is characterised by a large range of pollutants, does not allow understanding precisely the behaviour of individual congeners. The present in vitro experiment studied the impact of (i) the number and position of chlorine atoms of PCBs on their release from adipocytes and (ii) the presence of other PCB congeners on the mobilisation rate of such molecules. METHODOLOGY/PRINCIPAL FINDINGS: Differentiated rat adipocytes were used to compare the behaviour of PCB-28, -118 and -153. Cells were contaminated with the three congeners, alone or in cocktail, and a lipolysis was then induced with isoproterenol during 12 hours. Our data indicate that the three congeners were efficiently released from adipocytes and accumulated in the medium during the lipolysis. Interestingly, for a same level of cell lipids, PCB-153, a hexa-CB with two chlorine atoms in ortho-position, was mobilised slower than PCB-28, a tri-CB, and PCB-118, a penta-CB, which are both characterised by one chlorine atom in ortho-position. It suggests an impact of the chemical properties of pollutants on their mobilisation during periods of negative energy balance. Moreover, the mobilisation of PCB congeners, taken individually, did not seem to be influenced by the presence of other congeners within adipocytes. CONCLUSION/SIGNIFICANCE: These results not only highlight the obvious mobilisation of PCBs from adipocytes during lipolysis, in parallel to lipids, but also demonstrate that the structure of congeners defines their rate of release from adipocytes.

Polyunsaturated fatty acid metabolism in enterocyte models: T84 cell line vs. Caco-2 cell line.

Human colon carcinoma cell lines such as Caco-2 cells, model of mature enterocytes and T84 cells, model of crypt cells are useful to study interactions between nutrient processing and metabolic functions at intestinal level. Our study aimed at comparing the ability of Caco-2 and T84 cells (1) to incorporate dietary polyunsaturated fatty acids (PUFA), (2) to process them and (3) to sort them into neutral lipids (NL), free fatty acids (FFA) and phospholipids (PL). Caco-2 and T84 cells were exposed to a 7-day long supplementation with PUFA. The amounts of fatty acids accumulated and incorporated into the NL, FFA or PL fractions were higher in Caco-2 than in T84 cells. Caco-2 cells were able to significantly elongate C18 PUFA and C20 PUFA of both n-3 and n-6 families. In contrast, T84 cells were unable to elongate the n-6 fatty acids whereas elongation of n-3 fatty acids was detectable but marginal. Similarly, a Δ6 desaturase activity was observed in Caco-2 but not in T84 cells. In T84 cells, each exogenous fatty acid was predominantly accumulated in the PL fraction. In Caco-2 cells, C20 fatty acids and C18:2n-6 was preferentially accumulated in the PL fraction, while C22 PUFA and C18:3n-3 was preferentially accumulated in the NL fraction. Overall, this study has shown that Caco-2 and T84 cells, as models of intestinal mucosal cells, present large differences in PUFA accumulation capacity, specific elongase and desaturase activities and distribution pattern of exogenous PUFA and of their metabolites in the lipid classes.

Fatty acid mobilization and comparison to milk fatty acid content in northern elephant seals.

A fundamental feature of the life history of true seals, bears and baleen whales is lactation while fasting. This study examined the mobilization of fatty acids from blubber and their subsequent partitioning into maternal metabolism and milk production in northern elephant seals (Mirounga angustirostris). The fatty acid composition of blubber and milk was measured in both early and late lactation. Proportions of fatty acids in milk and blubber were found to display a high degree of similarity both early and late in lactation. Seals mobilized an enormous amount of lipid (~66 kg in 17 days), but thermoregulatory fatty acids, those that remain fluid at low temperatures, were relatively conserved in the outer blubber layer. Despite the stratification, the pattern of mobilization of specific fatty acids conforms to biochemical predictions. Long chain (>20C) monounsaturated fatty acids (MUFAs) were the least mobilized from blubber and the only class of fatty acids that showed a proportional increase in milk in late lactation. Polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) were more mobilized from the blubber, but neither proportion increased in milk at late lactation. These data suggest that of the long chain MUFA mobilized, the majority is directed to milk synthesis. The mother may preferentially use PUFA and SFA for her own metabolism, decreasing the availability for deposition into milk. The potential impacts of milk fatty acid delivery on pup diving development and thermoregulation are exciting avenues for exploration.

Sacha inchi (Plukenetia volubilis): a seed source of polyunsaturated fatty acids, tocopherols, phytosterols, phenolic compounds and antioxidant capacity.

Fatty acids (FA), phytosterols, tocopherols, phenolic compounds, total carotenoids and hydrophilic and lipophilic ORAC antioxidant capacities were evaluated in 16 cultivars of Sacha inchi (SI) seeds with the aim to valorise them and offer more information on the functional properties of SI seeds. A high α linolenic (α-Ln) fatty acid content was found in all cultivars (ω3, 12.8-16.0 g/100 g seed), followed by linoleic (L) fatty acid (ω6, 12.4-14.1g/100g seed). The ratio ω6/ω3 was within the 0.83-1.09 range. γ- and δ-tocopherols were the most important tocopherols, whereas the most representative phytosterols were ß-sitosterol and stigmasterol. Contents of total phenolics, total carotenoids and hydrophilic and lipophilic antioxidant capacities ranged from 64.6 to 80 mg of gallic acid equivalent/100g seed; from 0.07 to 0.09 mg of ß-carotene equivalent/100g of seed; from 4.3 to 7.3 and, from 1.0 to 2.8 µmol of Trolox equivalent/g of seed, respectively, among the evaluated SI cultivars. Results showed significant differences (p<0.05) among the evaluated SI cultivars in the contents of ω3, ω6, antioxidant capacities and other evaluated phytochemicals. SI seeds should be considered as an important dietary source of health promoting phytochemicals.

Uptake of conjugated linolenic acids and conversion to cis-9, trans-11-or trans-9, trans-11-conjugated linoleic acids in Caco-2 cells.

Dietary oils containing large amounts of conjugated linolenic acids (CLnA) may be regarded as a source of conjugated linoleic acids (CLA), which have been suspected to bear health-promoting properties. Indeed, CLnA can be converted into CLA in mammals. The objective of the present study was to investigate the uptake of CLnA and their metabolism into CLA in Caco-2 cells, as a validated in vitro model of the intestinal barrier. Caco-2 cells were incubated for 24 h in the presence of either α-eleostearic, ß-eleostearic, catalpic or punicic acid. We first observed that Caco-2 cells take these CLnA up at different rates and then convert them but with varying efficiency depending on the structure of the Δ13 double bond. Finally, the distribution of CLnA between neutral lipids (NL) and phospholipids appeared to be linked to their number of trans double bonds: the higher the number, the higher the accumulation in the NL fraction.

Differential changes of fat-soluble vitamins and pollutants during lactation in northern elephant seal mother-pup pairs.

We investigated the changes of vitamins A and E as well as PCBs and DDTs during lactation in northern elephant seal (Mirounga angustirostris) mother-pup pairs. On average, milk vitamin A concentrations were 6 times higher during late lactation than during early lactation, a pattern that differs dramatically from terrestrial mammals. Vitamin A concentrations also significantly increased in the inner blubber throughout lactation, whereas they remained constant in the outer blubber. Similar dynamics were observed for PCBs and DDTs in maternal blubber and milk. Blubber appears to be an important storage site for vitamin A and organochlorines in seals and a direct transfer of those molecules to the mammary gland may occur. The dynamics of vitamin A, PCBs and DDTs differed from those of vitamin E. There was a significant drop in milk vitamin E concentrations between early and late lactation, which is the usual pattern observed in terrestrial mammals. The dynamics of vitamin E in the blubber layers also differed from those of vitamin A, suggesting different mechanisms of mobilization and transfer into the milk.

Conversion of t11t13 CLA into c9t11 CLA in Caco-2 cells and inhibition by sterculic oil.

BACKGROUND: Conjugated linoleic acids (CLA), and principally c9t11 CLA, are suspected to have numerous preventive properties regarding non-infectious pathologies such as inflammatory diseases, atherosclerosis and several types of cancer. C9t11 CLA is produced in the rumen during biohydrogenation of linoleic acid, but can also be synthesized in mammalian tissues from trans-vaccenic acid (C18:1 t11) through the action of delta-9 desaturase (D9D). For several years, it is also known that c9t11 CLA can be synthesized from conjugated linolenic acids (CLnA), i.e. c9t11c13 CLnA and c9t11t13 CLnA. This study aimed at investigating to which extent and by which route c9t11 CLA can be produced from another isomer of CLA, the t11t13 CLA that is structurally very similar to c9t11t13 CLnA, in Caco-2 cells. METHODOLOGY/PRINCIPAL FINDINGS: Caco-2 cells were incubated for 24 h with 20 µmol/l of t11t13 CLA in the absence or presence of sterculic oil used as an inhibitor of D9D. Caco-2 cells were able to convert t11t13 CLA into c9t11 CLA, and c9t11t13 CLnA was formed as an intermediate compound. In the presence of sterculic oil, the production of this intermediate was decreased by 46% and the formation of c9t11 CLA was decreased by 26%. No other metabolite was detected. CONCLUSIONS/SIGNIFICANCE: These results not only highlight the conversion of t11t13 CLA into c9t11 CLA but demonstrate also that this conversion involves first a desaturation step catalysed by D9D to produce c9t11t13 CLnA and then the action of another enzyme reducing the double bond on the Δ13 position.