One-Step Concentration of Highly Unsaturated Fatty Acids from Tuna Oil by Low-Temperature Crystallization

Highly unsaturated fatty acids (HUFA), including eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3 and 22:5n‐6) and docosahexaenoic acid (DHA, 22:6n‐3), play an important role in human health and nutrition. In this study, concentration of HUFA in free fatty acids (FFA) form by low‐temperature crystallization was investigated. For this purpose, tuna oil (7.1% EPA, 26.8% DHA) was first converted into corresponding FFA. Subsequently, crystallization conditions of various solvent types, the ratio of FFA to acetonitrile, operation temperature and crystallization time were optimized at a small scale of 2 g tuna oil fatty acids. Taking purity and yield into account, the optimum conditions were a 1:10 ratio of FFA to acetonitrile (w/v), ?60 °C, and 1 h. The optimal conditions resulted in concentrations of EPA, DHA and HUFA of 15.1, 58.4 and 79.6%, respectively, with corresponding yields of 61.5, 61.8 and 60.7%, respectively. Crystallization was carried out under the optimal conditions at a large scale of 200 g tuna oil FFA, and a similar concentration result was achieved. After evaporating away the solvent, the residual amount of acetonitrile met the US Pharmacopoeia requirement of <410 ppm. The process for enrichment of HUFA is readily scalable, effective and time‐saving.     

Abnormalities in Plasma Phospholipid Fatty Acid Profiles of Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer‐related death worldwide. In the present study, we aimed to profile the possible changes in plasma phospholipid fatty acid composition of HCC patients, and to identify the fatty acid biomarkers that could distinguish HCC patients from healthy controls. A total of 37 plasma samples from healthy controls and HCC patients were collected and their phospholipid fatty acid profiles were characterized by gas chromatography–mass spectrometry followed by multivariate statistical analysis. Twenty‐five fatty acids were identified and quantified, their proportions varied greatly between two groups, suggesting each group has its own fatty acid pattern. Orthogonal partial least squares discriminant analysis in terms of fatty acid profiles showed that HCC patients could be clearly distinguished from healthy controls. More importantly, linoleic acid (18:2n‐6), oleic acid (18:1n‐9), arachidonic acid (20:4n‐6) and palmitic acid (16:0) were identified as the potential fatty acid biomarkers of HCC patients. Additionally, to further identify the major cause of the abnormality of plasma fatty acid profile, fatty acid distributions of cancerous tissue and its surrounding tissue from 42 HCC patients were also examined. Due to have similar variation trend of major fatty acid biomarkers, linoleic acid (18:2n‐6), oleic acid (18:1n‐9), abnormalities in plasma phospholipid fatty acid profiles of HCC patients may be mainly attributed to the alternation of intrinsic fatty acid metabolism caused by cancer per se, but not to the differences in dietary factors.     

Circulating tRNA Fragments as a Novel Biomarker Class to Distinguish Acute Stroke Subtypes

Early blood biomarkers to diagnose acute stroke could drastically reduce treatment delays. We investigated whether circulating small non-coding RNAs can serve as biomarkers to distinguish between acute ischemic stroke (IS), intracerebral hemorrhage (ICH) and stroke mimics (SM). In an ongoing observational cohort study, we performed small RNA-sequencing in plasma obtained from a discovery cohort of 26 patients (9 IS, 8 ICH and 9 SM) presented to the emergency department within 6 h of symptom onset. We validated our results in an independent dataset of 20 IS patients and 20 healthy controls. ICH plasma had the highest abundance of ribosomal and tRNA-derived fragments, while microRNAs were most abundant in plasma of IS patients. Combinations of four to five tRNAs yielded diagnostic accuracies (areas under the receiver operating characteristics curve) up to 0.986 (ICH vs. IS and SM) in the discovery cohort. Validation of the IS and SM models in the independent dataset yielded diagnostic accuracies of 0.870 and 0.885 to distinguish IS from healthy controls. Thus, we identified tRNA-derived fragments as a promising novel class of biomarkers to distinguish between acute IS, ICH and SM, as well as healthy controls.     

Fucoxanthin Enhances Chain Elongation and Desaturation of Alpha-Linolenic Acid in HepG2 Cells

Dietary fucoxanthin (FX), a carotenoid compound from brown algae, was found to increase docosahexaenoic acid (DHA, 22:6n‐3) and arachidonic acid (ARA, 20:4n‐6) in the liver of mice. DHA and ARA are known to be biosynthesized from the respective precursor α‐linolenic acid (ALA, 18:3n‐3) and linoleic acid (LNA, 18:2n‐6), through desaturation and chain elongation. We examined the effect of FX on the fatty acid metabolism in HepG2 cells (Hepatocellular carcinoma, human). In the first experiment, cells were co‐treated with ALA (100 μM) and FX (0–100 μM) or vehicle for 48 h. FX increased eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3), DHA at concentrations of ≥50 μM. To clarify the change in the metabolism of polyunsaturated fatty acid (PUFA), in the second experiment, cells were co‐treated with universally‐[¹³C]‐labeled (U‐[¹³C]‐) ALA (100 μM) and FX (100 μM) for 0.5, 3, 6, 24 and 48 h. [¹³C] labeled‐EPA, DPA and DHA content in HepG2 cells were all increased by FX after 48 h treatment. Furthermore, estimated delta‐5 desaturase (D5D) but not delta‐6 desaturase (D6D) activity index was increased at 48 h. These results suggested that FX may enhance the conversion of ALA to longer chain n‐3 PUFA through increasing D5D activity in the liver.     

Impact of a Standard Rodent Chow Diet on Tissue n‐6 Fatty Acids, Δ9‐Desaturation Index,and Plasmalogen Mass in Rats Fed for One Year

Although many studies focus on senescence mechanisms, few habitually consider age as a biological parameter. Considering the effect of interactions between food and age on metabolism, here we depict the lipid framework of 12 tissues isolated from Sprague–Dawley rats fed standard rodent chow over 1 year, an age below which animals are commonly studied. The aim is to define relevant markers of lipid metabolism influenced by age in performing a fatty acid (FA) and dimethylacetal profile from total lipids. First, our results confirm impregnation of adipose and muscular tissues with medium‐chain FA derived from maternal milk during early infancy. Secondly, when animals were switched to standard croquettes, tissues were remarkably enriched in n‐6 FA and especially 18:2n‐6. This impregnation over time was coupled with a decrease of the desaturation index and correlated with lower activities of hepatic Δ5‐ and Δ6‐desaturases. In parallel, we emphasize the singular status of testis, where 22:5n‐6, 24:4n‐6, and 24:5n‐6 were exceptionally accumulated with growth. Thirdly, 18:1n‐7, usually found as a discrete FA, greatly accrued over the course of time, mostly in liver and coupled with Δ9‐desaturase expression. Fourthly, skeletal muscle was characterized by a surprising enrichment of 22:6n‐3 in adults, which tended to decline in older rats. Finally, plasmalogen‐derived dimethylacetals were specifically abundant in brain, erythrocytes, lung, and heart. Most notably, a shift in the fatty aldehyde moiety was observed, especially in brain and erythrocytes, implying that red blood cell analysis could be a good indicator of brain plasmalogens.     

Stroke and plasma markers of milk fat intake – a prospective nested case-control study

Background  

Dairy products are high in saturated fat and are traditionally a risk factor for vascular diseases. The fatty acids 15:0 and 17:0 of plasma lipids are biomarkers of milk fat intake. The aim of the present study was to evaluate the risk of a first-ever stroke in relation to the plasma milk fat biomarkers.     

Lipidomic Profiling Reveals the Effect of Egg Components on Nonalcoholic Steatosis in HepG2 Cells and Its Involved Mechanisms

Non‐alcoholic fatty liver disease (NAFLD) is a major cause of cardiovascular disease. The relationship between egg consumption and NAFLD is still controversial for its high cholesterol content. In this study, the effects of different egg components (egg white (EW), egg yolk (EY), and whole egg (WE)) on NAFLD are examined using oleic acid (OA)‐induced HepG2 cells with UPLC‐ESI‐MS/MS approach. The results show EY could affect the lipid profile effectively by increasing phosphocholine (PC), phosphatidylglycerol (PG), and carnitine (CAR). Orthogonal projections to latent structures?discriminate analysis (OPLS‐DA) combine with S‐plot analysis select 10, 82, and 20 potential biomarkers in EW, EY, and WE group, respectively. Up‐regulated TG, DG, and down‐regulated lysophosphatidylcholines (lysoPC), lysophosphatidylethanolamine (lysoPE) biomarkers are found in EY group, while down‐regulated TG and FFA are found in EW and WE group. Glycerolipid and choline metabolism are the most involved pathways affected by EY and WE. In addition, the mechanism is associated with the expression of Pla2g15, Pnpla6‐1, Gad1, and involved lipogenic genes ABC1 and PPARα. This study suggests that WE treatment can ameliorate OA‐induced hepatic steatosis by inhibiting TG accumulation, while EY seems slightly accelerate hepatic steatosis. Furthermore, the effects are closely associated with its effects on glycerolipid metabolism. Practical applications: Nonalcoholic fatty liver disease (NAFLD) is a worldwide disease, while the associations between egg consumption and NAFLD are still poorly understood. This study investigates the effects of egg components on NAFLD in oleic acid (OA)‐induced HepG2 cells based on a targeted lipidomics approach. The results indicate that WE (whole egg) treatment could ameliorate OA‐induced hepatic steatosis by inhibiting TG and FFA accumulation, which is closely associated with glycerolipid metabolism. The results provide knowledge and understanding of the effects of egg on NAFLD and involved mechanism, and further provided nutritional guidelines for egg consumption.     

Artificial Rearing of Infant Mice Leads to n-3 Fatty Acid Deficiency in Cardiac,Neural and Peripheral Tissues

The ability to control the fatty acid content of the diet during early development is a crucial requirement for a one-generation model of docosahexaenoic acid (DHA; 22:6n3) deficiency. A hand feeding method using artificial rearing (AR) together with sterile, artificial milk was employed for feeding mice from postnatal day 2–15. The pups were fed an n-3 fatty acid adequate (3% α-linolenic acid (LNA; 18:3n3) + 1% 22:6n3) or a deficient diet (0.06% 18:3n3) with linoleic acid (LA; 18:2n6) as the only dietary source of essential fatty acids by AR along with a dam-reared control group (3.1% 18:3n3). The results indicate that restriction of n-3 fatty acid intake during postnatal development leads to markedly lower levels of brain, retinal, liver, plasma and heart 22:6n3 at 20 weeks of age with replacement by docosapentaenoic acid (DPAn6; 22:5n6), arachidonic acid (ARA; 20:4n6) and docosatetraenoic acid (DTA; 22:4n6). A detailed analysis of phospholipid classes of heart tissue indicated that phosphatidylethanolamine, phosphatidylcholine and cardiolipin were the major repositories of 22:6n3, reaching 40, 29 and 15%, respectively. A novel heart cardiolipin species containing four 22:6n3 moieties is described. This is the first report of the application of artificially rearing to mouse pup nutrition; this technique will facilitate dietary studies of knockout animals as well as the study of essential fatty acid (EFA) functions in the cardiovascular, neural and other organ systems.     

Marine phospholipids as dietary carriers of long‐chain polyunsaturated fatty acids

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are polyunsaturated fatty acids (PUFA) of the n‐3 series. Fish oil is a classical source of n‐3 PUFA, where they occur in the form of triacylglycerols (TAG). However, new sources of n‐3 PUFA esterified in phospholipids (PL) are emerging. We prepared liposomes from a natural marine lipid extract and examined their behaviour under conditions mimicking that of the gastrointestinal tract. This physicochemical approach proved that liposomes could be used as an effective oral PUFA delivery system. In vivo studies in rats were performed to examine the metabolic fate of EPA (20:5 n‐3) and DHA (22:6 n‐3) delivered either in PL from liposomes or in TAG from oil. Liposome ingestion increased PUFA bioavailability in lymph compared with fish oil. The proportion of n‐3 PUFA esterified in the sn‐2 position of chylomicron TAG depended on the dietary lipid source. Complex time‐course profiles were observed for plasma lipids with liposome supplementation over a 2‐week period, suggesting time‐dependent regulations. Taken together, the type of PUFA, EPA or DHA, as well as its intramolecular distribution in chylomicron TAG seemed to influence the metabolic fate of the fatty acids and their physiological activities.     

White Bass (<Emphasis Type="Italic">Morone chrysops</Emphasis>) Preferentially Retain n-3 PUFA in Ova When Fed Prepared Diets with Varying FA Content

We evaluated the fatty acid (FA) composition of broodstock white bass ova fed one of six commercial diets with increasing polyunsaturated FA content (n‐6/n‐3 ratio; 0.36, 0.39, 0.46, 0.83, 1.07, 1.12) eight weeks prior to sampling. Fatty acid profiles of ova from brooders fed each of the six diets were significantly altered according to canonical discriminant analysis. Ova FA profiles resulting from the 0.39 diet separated those from the 0.36 diet based on lower 18:2n‐6 (LNA) and higher 20:1n‐9 concentrations from the 0.36 diet. Ova profiles were further separated based on lower concentrations of 22:5n‐3 (DPA) from the 0.46 diet, lower concentrations of 20:5n‐3 (EPA) in the 1.12 and 0.83 diets, and lower concentrations of 22:6n‐3 (DHA) in all other diets relative to the 0.46 diet. Changes in ova FA profile at four and eight weeks were consistent with dietary intake with an approximate 2% increase in any given FA class with increasing time on individual diet. There was no correlation between dietary ARA concentrations (0.7–1.1 mol%), or dietary EPA/ARA ratios (7–15), and the concentrations (1.4–1.7 mol%) or ratios (3.3–4.4) found in the ova by diet. Our results suggest that white bass females have the ability to preferentially incorporate n‐3 PUFA, particularly DHA, suggesting mobilization of this FA from other tissues for ova deposition or preferential dietary incorporation of PUFA into ova. These results will add to the limited FA information available in white bass and enable nutritionists to formulate broodstock diets that maximize reproductive potential in this species.     

Plasma Phospholipid Fatty Acid Profile is Altered in Both Septic and Non-Septic Critically Ill: A Correlation with Inflammatory Markers and Albumin

This study analyzes fatty acid (FA) composition in plasma lipids and erythrocyte phospholipids while comparing septic and non‐septic critically ill patients. The aim was to describe impacts of infection and the inflammatory process. Patients with severe sepsis (SP, n = 13); age‐, sex‐ and APACHE II score‐matched non‐septic critically ill with systemic inflammatory response syndrome (NSP, n = 13); and age‐/sex‐matched healthy controls (HC, n = 13) were included in a prospective case–control study during the first 24 h after admission to the intensive care unit. In both SP and NSP, lower n‐6 polyunsaturated FA (PUFA) accompanied by higher proportions of monounsaturated FA (MUFA) in plasma phospholipids (PPL) was observed relative to HC. MUFA proportion was negatively correlated with n‐6 PUFA, high density lipoprotein cholesterol (HDL‐C), and albumin. MUFA was positively correlated with C‐reactive protein (CRP), procalcitonin (PCT), interleukins (IL‐6, IL‐10), oxidized low density lipoproteins (ox‐LDL), and conjugated dienes (CD). In both SP and NSP, inflammatory and lipid peroxidation markers were significantly higher—CRP (p < 0.001; p = 0.08), IL‐6, IL‐10, TNF‐α (p < 0.01, p = 0.06), ox‐LDL, and CD while total cholesterol, HDL‐C, LDL‐C albumin, and 20:4n‐6/22:6n‐3 and n‐6/n‐3 ratios were lower compared to HC. In conclusion, the changes in plasma lipid FA profile relate to the intensity of inflammatory and peroxidative response regardless of insult etiology. The lower MUFA and higher n‐6 PUFA proportions in PPL were inversely correlated with cholesterol and albumin levels.     

Analysis of fatty acid profile in plasma phospholipids by solid‐phase extraction in combination with GC

Phospholipids are recognised as an important source and transport form for metabolically active fatty acids. Therefore, detailed analysis of fatty acid profiles in plasma phospholipids as marker for dietary habits or interventions gains more and more importance. Appropriate analytical methods described so far are either expensive or susceptible to handling errors. We developed a method to separate plasma phospholipids by acetone fractionation combined with SPE in order to analyse the fatty acid compositions in phospholipid fractions of human plasma by GC analysis. The method has been validated in order to be applied to the routinely performed analysis of the samples of patients who will be participating in a dietary supplement study. The method presented here was successfully validated and is stable, efficient and reproducible. It can be used in a routine fashion to deliver the fatty acid profile [palmitic acid (16:0), heptadecanoic acid (17:0), stearic acid (18:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6), linolenic acid (18:3n‐3), arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3)] in plasma phospholipid samples. Using a sample volume of 500 µL, recovery of plasma phospholipids is 92 ± 11%; LOQ is 2.2 µg fatty acid/mL. A set of samples from cancer patients and healthy individuals was analysed and confirmed the applicability of the described method.     

Combined Urea Complexation and Argentated Silica Gel Column Chromatography for Concentration and Separation of PUFAs from Tuna Oil: Based on Improved DPA Level

Eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA) isomers (22:5n‐6 and 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) derived from tuna oil were concentrated by three stages of urea fractionation at various crystallization temperatures and different fatty acid/urea ratios. Thereafter, polyunsaturated fatty acids concentrate containing comparatively enriched DPA levels was purified by argentated silica gel column chromatography. A product containing 22.2 ± 0.6 % EPA, 4.6 ± 0.0 % DPAn‐6, 5.9 ± 0.1 % DPAn‐3 and 42.3 ± 1.2 % DHA was obtained at 1:1.6 fatty acid/urea ratio (w/w) by crystallization at ?8 °C for 16 h, ?20 °C for 8 h, and ?8 °C for 16 h. A DPA isomer concentrate containing 26.1 ± 0.5 % DPAn‐6 and 22.3 ± 0.4 % DPAn‐3 was achieved by argentated silica gel chromatography in the 6 % acetone/n‐hexane solvent fraction (v/v), and the recovery of both fatty acids was 66.1 ± 3.2 and 70.7 ± 2.2 %, respectively. Furthermore, 91.9 ± 2.5 % EPA and 99.5 ± 2.1 % DHA with recoveries of 47.8 ± 2.0 and 56.7 ± 3.3 %, respectively, were obtained in various fractions.     

FA composition of cholesteryl esters and phospholipids in maternal plasma during pregnancy and at delivery and in cord plasma at birth

The purpose of this study was to assess the FA composition of both cholesteryl esters (CE) and phospholipids (PL) in maternal plasma during pregnancy and at delivery and in umbilical plasma at birth. A longitudinal study of 32 normal pregnant women was carried out with three cutoff points during pregnancy (first, second, and third trimester) and at delivery. Few significant differences occurred in the FA profile of maternal CE: 18∶1n−9 increased, 18∶2n−6 dropped slightly, and 18∶3n−3 decreased with progressing gestation. In maternal PL, long-chain highly unsaturated FA concentrations dropped and were replaced by saturated FA as gestation progressed. Additionally, changes in saturated FA in PL occurred: Shorter-chain 16∶0 was higher whereas longer-chain 18∶0 was lower at delivery compared to early pregnancy. The FA profile of umbilical venous plasma was strikingly different from that of maternal plasma at delivery. Cord plasma CE contained more saturated and monounsaturated FA than maternal CE. The polyunsaturates 18∶2n−6 and 18∶3n−3 are lower in umbilical CE than in maternal CE whereas 20∶4n−6 and 22∶6n−3 are twice as high in umbilical CE. Cord plasma PL have a higher content of long-chain highly unsaturated FA than maternal plasma PL at delivery. In contrast to maternal plasma PL, 16∶0 was lower and longer-chain saturated FA were higher in cord plasma PL. The FA profile of umbilical plasma at birth shows preferential accumulation of 20∶4n−6 and 22∶6n−3, with low concentrations of 18∶2n−6 and 18∶3n−3 in CE and PL, indicating a preferential supply of the fetus with long-chain highly unsaturated FA needed for fetal development.     

Lower Concentration of n‐3 in the Red Blood Cells and Plasma of Lambs when their Dams were Fed a Diet High Compared with Low in n‐6 Fatty Acids at Joining

Feeding ewes a diet high in n‐6 in late gestation can affect fatty acid concentrations in the newborn lamb. The effect of feeding ewes a high n‐6 diet prior to conception and in early gestation on lamb n‐6 and n‐3 status has not previously been examined. The aim of the current study was to determine whether the concentration of n‐6 was higher and n‐3 was lower in lamb red blood cells (RBC) and plasma when Merino dams were fed a diet high in n‐6 either pre‐conception only or both pre‐conception and in early gestation. Dams were fed a diet low (silage) or high (oats/CSM) in n‐6 for either 6 weeks pre‐mating only or 6 weeks pre‐mating and 17 days post‐mating. The fatty acid status of lamb RBC and plasma was determined following birth and compared with dam fatty acids around parturition. The concentration of lamb RBC and plasma n‐3 was lower (p < 0.05) when dams received the high n‐6 compared with low‐n‐6 diet around mating, independent of the length of time of feeding. The concentration of n‐3 in lamb plasma was also higher when lambs were assessed as being likely rather than unlikely to have suckled prior to blood collection. Lamb RBC and plasma n‐3 fatty acids were lower when dams were fed the high compared with the low n‐6 diet for only a short time around mating. Transfer of fatty acids via the placenta and milk may account for the differences.     

Monocyte chemotactic protein-1 as a potential biomarker for early anti-thrombotic therapy after ischemic stroke

Inflammation following ischemic brain injury is correlated with adverse outcome. Preclinical studies indicate that treatment with acetylsalicylic acid + extended-release dipyridamole (ASA + ER-DP) has anti-inflammatory and thereby neuroprotective effects by inhibition of monocyte chemotactic protein-1 (MCP-1) expression. We hypothesized that early treatment with ASA + ER-DP will reduce levels of MCP-1 also in patients with ischemic stroke. The EARLY trial randomized patients with ischemic stroke or TIA to either ASA + ER-DP treatment or ASA monotherapy within 24 h following the event. After 7 days, all patients were treated for up to 90 days with ASA + ER-DP. MCP-1 was determined from blood samples taken from 425 patients on admission and day 8. The change in MCP-1 from admission to day 8 did not differ between patients treated with ASA + ER-DP and ASA monotherapy (p > 0.05). Comparisons within MCP-1 baseline quartiles indicated that patients in the highest quartile (>217-973 pg/mL) showed improved outcome at 90 days if treated with ASA + ER-DP in comparison to treatment with ASA alone (p = 0.004). Our data does not provide any evidence that treatment with ASA + ER-DP lowers MCP-1 in acute stroke patients. However, MCP-1 may be a useful biomarker for deciding on early stroke therapy, as patients with high MCP-1 at baseline appear to benefit from early treatment with ASA + ER-DP.     

Fatty Acid,Lipid Class,and Phospholipid Molecular Species Composition of the Soft Coral Xenia sp. (Nha Trang Bay,the South China Sea,Vietnam)

The soft corals of the genus Xenia are common for Indo‐Pacific reef ecosystems. Lipid class, fatty acid (FA), phospho‐ and phosphonolipid molecular species compositions were identified for the first time in the soft coral Xenia sp. from Vietnam. Total lipids consisted predominantly of waxes, monoalkyl diacylglycerols, triacylglycerols, sterols, and polar lipids (21.4, 7.7, 14.2, 10.5, and 36.7 %, respectively). Sesquiterpene alcohol, valerenenol, was found. Acids 16:0, 18:3n‐6, 20:4n‐6, and 20:5n‐3 dominated in total FA. The markers of zooxanthellae (18:4n‐3 and 18:5n‐3) and octocorals (24:5n‐6 and 24:6n‐3) were detected. Acids 18:5n‐3, 20:4n‐6, 22:4n‐6, and 24:5n‐6 concentrated in FA of polar lipids, whereas 14:0, 16:0, 16:1n‐7, 18:2n‐6, and 18:3n‐6 were the major FA of neutral lipids. ChoGpl, EtnGpl, SerGpl, CAEP, PtdIns, and lyso ChoGpl constituted 39.5, 20.8, 20.5, 9.7, 4.3, and 5.3 %, respectively, of the sum of phospho‐ and phosphonolipids. Thirty‐two molecular species of phospholipids and ceramide aminoethylphosphonate (CAEP) were determined by high resolution tandem mass spectrometry. Lyso 18:0e PakCho (4.1 %), 18:0e/20:4 PakCho (20.5 %), 18:1e/20:4 PlsEtn (18.0 %), 18:0e/24:5 PakSer (14.0 %), and 16:0 CAEP (9.6 %) were the major molecular species. EtnGpl and PtdIns mainly consisted of alkenyl acyl and diacyl forms, respectively. Alkyl acyl forms predominated in ChoGpl and SerGpl. Acid 24:5n‐6 was a principal FA in SerGpl, whereas 20:4n‐6 was more abundant in ChoGpl and EtnGpl. PtdIns contained various C_20–24 PUFA. In the context of chemotaxonomy of corals, Xenia sp. has the lipid composition typical for soft corals and the FA profile similar to that of alcyonarians with the high level of 18:3n‐6.     

Essential Fatty Acid Assimilation and Synthesis in Larvae of the Bivalve Crassostrea gigas

Essential fatty acids (EFA) are important for bivalve larval survival and growth. The purpose of this study was to quantitatively assess for the first time through a mass‐balance approach dietary EFA incorporation and synthesis within Crassostrea gigas larvae. A first experiment was carried out using two microalgae, Tisochrysis lutea (T) and Chaetoceros neogracile (Cg), as mono‐ and bi‐specific diets. A second experiment using a similar design was performed to confirm and extend the results obtained in the first. Flow‐through larval rearing was used for accurate control of food supply and measurement of ingestion. Non‐methylene‐interrupted fatty acids were synthetized from precursors supplied in the diet: 16:1n‐7 and 18:1n‐9, mediated by Δ5 desaturase. Moreover, this Δ5 desaturase presumably allowed larvae to convert 20:3n‐6 and 20:4n‐3 to 20:4n‐6 and 20:5n‐3, respectively, when the product EFA were poorly or not supplied in the diet, as when larvae were fed T exclusively. Under our experimental conditions, none of the diets induced 22:6n‐3 synthesis; however, 22:6n‐3 incorporation into larval tissues occurred selectively under non‐limiting dietary supply to maintain optimal levels in the larvae. This combination of flow‐through larval rearing and biochemical analysis of FA levels could be applied to additional dietary experiments to precisely define optimal levels of EFA supply.     

n‐3 PUFA Induce Microvascular Protective Changes During Ischemia/Reperfusion

Ischemia/reperfusion (I/R) injury can occur in consequence of myocardial infarction, stroke and multiple organ failure, the most prevalent cause of death in critically ill patients. I/R injury encompass impairment of endothelial dependent relaxation, increase in macromolecular permeability and leukocyte‐endothelium interactions. Polyunsaturated fatty acids (n‐3 PUFA), such as eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) found in fish oil have several anti‐inflammatory properties and their potential benefits against I/R injury were investigated using the hamster cheek pouch preparation before and after ischemia. Before the experiments, hamsters were treated orally with saline, olive oil, fish oil and triacylglycerol (TAG) and ethyl ester (EE) forms of EPA and DHA at different daily doses for 14 days. Fish oil restored the arteriolar diameter to pre ischemic values during reperfusion. At onset and during reperfusion, Fish oil and DHA TAG significantly reduced the number of rolling leukocytes compared to saline and olive oil treatments. Fish oil, EPA TAG and DHA TAG significantly prevented the rise on leukocyte adhesion compared to saline. Fish oil (44.83 ± 3.02 leaks/cm²), EPA TAG (31.67 ± 2.65 leaks/cm²), DHA TAG (41.14 ± 3.63 leaks/cm²), and EPA EE (30.63 ± 2.25 leaks/cm²), but not DHA EE (73.17 ± 2.82 leaks/cm²) prevented the increase in macromolecular permeability compared to saline and olive oil (134.80 ± 1.49 and 121.00 ± 4.93 leaks/cm², respectively). On the basis of our findings, we may conclude that consumption of n‐3 polyunsaturated fatty acids, especially in the triacylglycerol form, could be a promising therapy to prevent microvascular damage induced by ischemia/reperfusion and its consequent clinical sequelae.     

Postprandial Lipid Responses do not Differ Following Consumption of Butter or Vegetable Oil when Consumed with Omega-3 Polyunsaturated Fatty Acids

Dietary saturated fat (SFA) intake has been associated with elevated blood lipid levels and increased risk for the development of chronic diseases. However, some animal studies have demonstrated that dietary SFA may not raise blood lipid levels when the diet is sufficient in omega‐3 polyunsaturated fatty acids (n‐3PUFA). Therefore, in a randomised cross‐over design, we investigated the postprandial effects of feeding meals rich in either SFA (butter) or vegetable oil rich in omega‐6 polyunsaturated fatty acids (n‐6PUFA), in conjunction with n‐3PUFA, on blood lipid profiles [total cholesterol, low density lipoprotein cholesterol (LDL‐C), high density lipoprotein cholesterol (HDL‐C) and triacylglycerol (TAG)] and n‐3PUFA incorporation into plasma lipids over a 6‐h period. The incremental area under the curve for plasma cholesterol, LDL‐C, HDL‐C, TAG and n‐3PUFA levels over 6 h was similar in the n‐6PUFA compared to SFA group. The postprandial lipemic response to saturated fat is comparable to that of n‐6PUFA when consumed with n‐3PUFA; however, sex‐differences in response to dietary fat type are worthy of further attention.