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Improving nanomedicine uptake by tumor cells is key to achieving intracellular drug delivery. In this study, we found that methyl-β-cyclodextrin (MβCD) can significantly promote the intracellular accumulation of nanoparticulated α-linolenic acid-paclitaxel conjugates (ALA-PTX NPs) via enhanced clathrin-mediated endocytosis and limited degradation in lysosomes. Our in vitro results indicated that MβCD not only reduced the plasma membrane cholesterol content and increased plasma membrane fluidity, leading to ALA-PTX NPs being more easily incorporated into the plasma membrane, further enhancing membrane fluidity and making the plasma membrane more susceptible to tensile deformation, forming intracellular vesicles to enhance ALA-PTX NP cellular uptake, but also destroyed lysosomes and then limited ALA-PTX NPs' degradation in lysosomes. In HepG2 tumor-bearing mice, MβCD was also able to enhance the antitumor activity of ALA-PTX NPs in vivo. Moreover, we found that MβCD specifically promoted PUFA-paclitaxel conjugate NP cellular uptake. The cellular uptake of PTX liposome which shares an endocytosis pathway with ALA-PTX NPs could be enhanced by MβCD combined with ALA or ALA-PTX NPs. Therefore, we suggested that MβCD combined with polyunsaturated fatty acid-conjugation would be an effective strategy for improving intracellular delivery of nanoparticulated chemotherapeutic drugs used for combination administration to enhance antitumor efficiency.

Scope: The article investigates the FADS1 rs174550 genotype interaction with dietary intakes of high linoleic acid (LA) and high alpha-linolenic acid (ALA) on the response of fatty acid composition of plasma phospholipids (PLs), and of markers of low-grade inflammation and glucose-insulin homeostasis., Methods and Results: One-hundred thirty homozygotes men for FADS1 rs174550 SNP (TT and CC genotypes) were randomized to an 8-week intervention with either LA- or ALA-enriched diet (13 E% PUFA). The source of LA and ALA are 30-50 mL of sunflower oil (SFO, 62-63% LA) and Camelina sativa oil (CSO, 30- are randomized to an 35% ALA), respectively. In the SFO arm, there is a significant genotype x diet interaction for the proportion of arachidonic acid in plasma phospholipids (p < 0.001), disposition index (DI 30 ) (p = 0.039), and for serum high-sensitive c-reactive protein (hs-CRP, p = 0.029) after excluding the participants with hs-CRP concentration of >10 mg L -1 and users of statins or anti-inflammatory therapy. In the CSO arm, there are significant genotype x diet interactions for n-3 polyunsaturated fatty acids, but not for the clinical characteristics., Conclusions: The FADS1 genotype modifies the response to high PUFA diets, especially to high-LA diet. These findings suggest that approaches considering FADS variation may be useful in personalized dietary counseling., (© 2021 The Authors. Molecular Nutrition & Food Research published by Wiley-VCH GmbH.)

Stroke severely impairs quality of life and has a high mortality rate. On the other hand, dietary docosahexaenoic acid (DHA) prevents neuronal damage. In this review, we describe the effects of dietary DHA on ischemic stroke-associated neuronal damage and its role in stroke prevention. Recent epidemiological studies have been conducted to analyze stroke prevention through DHA intake. The effects of dietary intake and supply of DHA to neuronal cells, DHA-mediated inhibition of neuronal damage, and its mechanism, including the effects of the DHA metabolite, neuroprotectin D1 (NPD1), were investigated. These studies revealed that DHA intake was associated with a reduced risk of stroke. Moreover, studies have shown that DHA intake may reduce stroke mortality rates. DHA, which is abundant in fish oil, passes through the blood-brain barrier to accumulate as a constituent of phospholipids in the cell membranes of neuronal cells and astrocytes. Astrocytes supply DHA to neuronal cells, and neuronal DHA, in turn, activates Akt and Raf-1 to prevent neuronal death or damage. Therefore, DHA indirectly prevents neuronal damage. Furthermore, NDP1 blocks neuronal apoptosis. DHA, together with NPD1, may block neuronal damage and prevent stroke. The inhibitory effect on neuronal damage is achieved through the antioxidant (via inducing the Nrf2/HO-1 system) and anti-inflammatory effects (via promoting JNK/AP-1 signaling) of DHA., (© 2020 Wiley Periodicals LLC.)

The aim of this study was to investigate the bioavailability and bioactivity of perilla (Perilla frutescens) oil nanoemulsions prepared at different homogenization pressures by measuring the weight, fatty acid profile, and antioxidant and anti-inflammatory properties in rats. The high-pressure homogenization significantly reduced the particle size of perilla oil nanoemulsions and enhanced their stability, and the minimum particle size was 293.87 ± 6.55 nm at 120 MPa. There was an increase in the weight and fatty acid levels in the plasma and liver of test group rats. The highest glutathione (GSH) and the lowest malondialdehyde (MDA) levels of 18.76 ± 10.51 mg GSH/g prot and 20.27 ± 2.46 nmol/mg prot, respectively, were recorded in rats administrated perilla oil nanoemulsions prepared at 120 MPa. However, there was no significant difference in superoxide dismutase activity (SOD) between the groups. The interferon-gamma (IL-γ), interleukin-1 beta (IL-1β), IL-6 (interleukin-6), and IL-8 (interleukin-8) levels in the test groups were lower than those in the blank and control groups at 8 hr after lipopolysaccharide injection. The IL-1β, IL-6, and IL-8 levels were 49.52 ± 14.06, 90.13 ± 6.04, and 419.71 ± 32.03 ng/L, respectively, in rats treated with perilla oil nanoemulsions prepared at 120 MPa. Both perilla oil and its nanoemulsions decreased estradiol levels and damaged the ovaries. Overall, our findings show that the test nanoemulsions enhanced the bioavailability of perilla oil, which resulted in enhanced antioxidant and anti-inflammatory responses; thus, we provide a new approach to deliver perilla oil. PRACTICAL APPLICATION: Nanoemulsions can be used to deliver drugs and bioactive compounds, and perilla oil nanoemulsions can be used in healthcare products and beverage industries., (© 2020 Institute of Food Technologists®.)

Scope: To compare the effects of supplementary eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) versus α-linolenic acid (ALA) on lipid profiles, inflammatory status, and fatty acid composition of peripheral blood mononuclear cells (PBMCs) in hypercholesterolemic adults., Methods and Results: A randomized, controlled, double-blind trial is conducted to examine the effects of consumption of control oil, 4.2 g/d ALA, 7.2 g/d ALA, 1.8 g/d DHA+EPA, or 3.6 g/d EPA+DHA for 12 weeks on lipid profiles, fatty acid composition of PBMCs and in vitro production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) by PBMCs in 123 subjects with hypercholesteremia. After the intervention, subjects who receive a low and high dose of DHA/EPA experience 11.99% and 15.78% decreases in triglycerides which is significantly different from that of the control group (p < 0.05). The in vitro study indicates that supplementation of high-dose DHA+EPA induces the greatest decrease of IL-6 production by PBMCs relative to other groups (p = 0.046). ALA intervention significantly increases the PBMCs composition of ALA but not EPA/DHA., Conclusion: EPA+DHA, but not ALA, improves lipids and inflammation status in hypercholesterolemic adults. Supplementation of ALA does not increase the PBMCs composition of EPA/DHA in middle-aged to elderly Chinese., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Scope: The study aims at identifying 1) the most sensitive compartment among plasma phospholipids, erythrocytes, and LDL for studying alpha-linolenic acid (ALA) conversion, and 2) whether ALA incorporation and conversion is saturable after administration of 13 C-labeled ALA-rich linseed oil (LO). The effect of a daily intake of 7 g nonlabeled LO (>43% w/w ALA) for 1 month after bolus administration of 7 g 13 C-labeled LO on day 1, and for 2 months after bolus administration of 7 g 13 C-labeled LO on day 1 and day 29 on 13 C-ALA incorporation and conversion into its higher homologs is investigated in healthy volunteers., Methods and Results: Incorporation and conversion of LO-derived 13 C-labeled ALA is quantified by applying compartmental modeling. After bolus administration, a fractional conversion of approximately 30% from 13 C-ALA to 13 C-DHA is calculated as reflected by the LDL compartment. Treatment with LO for 8 weeks induces a mean reduction of 13 C-ALA conversion to 13 C-DHA by 48% as reflected by the LDL compartment, and a mean reduction of the 13 C-ALA incorporation into LDL by 46%., Conclusion: A 2-month dietary intake of a high dose of LO is sufficient to reach saturation of ALA incorporation into LDL particles, which are responsible for ALA distribution in the body., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chronic inflammation, mediated in large part by proinflammatory macrophage populations, contributes directly to the induction and perpetuation of metabolic diseases, including obesity, insulin resistance and type 2 diabetes. Polyunsaturated fatty acids (PUFAs) can have profound effects on inflammation through the formation of bioactive oxygenated metabolites called oxylipins. The objective of this study was to determine if exposure to the dietary omega-3 PUFA α-linolenic acid (ALA) can dampen the inflammatory properties of classically activated (M1-like) macrophages derived from the human THP-1 cell line and to examine the accompanying alterations in oxylipin secretion. We find that ALA treatment leads to a reduction in lipopolysaccharide (LPS)-induced interleukin (IL)-1β, IL-6 and tumor necrosis factor-α production. Although ALA is known to be converted to longer-chain PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), DHA oxylipins were reduced overall by ALA treatment, as was LPS-induced secretion of EPA oxylipins. In contrast, we observed profound increases in oxylipins directly derived from ALA. Lipoxygenase products of linoleic acid were also dramatically increased, and LPS-induced production of AA oxylipins, particularly prostaglandin D2, was reduced. These results suggest that ALA may act to dampen the inflammatory phenotype of M1-like macrophages by a unique set of mechanisms distinct from those used by the long-chain omega-3 fatty acids EPA and DHA. Thus, there is strong rationale for investigating the functions of ALA oxylipins and lesser-known LA oxylipins since they hold promise as anti-inflammatory agents., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The oral bioavailability of felodipine, a dihydropyridine calcium channel antagonist, is about 15%. This may be due to poor water solubility, and a lower intestinal permeability than a BCS class I drug, and hepatic first-pass metabolism of the drug. Many drugs are unpopular due to solubility issues. The goal of this study was to develop and optimize a felodipine-containing microemulsion to improve the intestinal permeability and bioavailability of the drug. The felodipine microemulsions were developed with the selected components, i.e., α-linolenic acid as the oil phase, Tween 80 as a surfactant, and isopropyl alcohol as co-surfactant using Box-Behnken design and characterized for in vitro release and particle size. The optimized felodipine-loaded microemulsion was investigated for physicochemical interaction, surface morphology, intestinal permeability, rheology, cytotoxicity, cellular uptake, pharmacodynamic (electrocardiogram and heart rate variability), and pharmacokinetic studies to explore its suitability as a promising oral drug delivery system for the treatment of hypertension. The optimized felodipine-loaded microemulsion showed significantly higher (P < 0.05) apparent permeability coefficients (Papp) at 7.918 × 10 -5  cm/s after 1 h, when compared with conventional formulations that are marketed tablet, drug oily solution, and drug emulsion, which showed a maximum Papp of 3.013, 4.428, and 5.335 × 10 -5  cm/s, respectively. The optimized felodipine-loaded microemulsion showed biocompatibility and no cytotoxicity. Cellular uptake studies confirmed payload delivery to a cellular site on the J774.A1 cell line. The rheology study of the optimized felodipine-loaded microemulsion revealed Newtonian-type flow behavior and discontinuous microemulsion formation. In pharmacodynamic studies, significant differences in parameters were observed between the optimized felodipine-loaded microemulsion and marketed formulation. The optimized felodipine-loaded microemulsion showed significantly higher (p < 0.01) C max (7.12 ± 1.04 μg/ml) than marketed tablets (2.44 ± 1.03 μg/ml). It was found that AUC last obtained from the optimized felodipine-loaded microemulsion (84.53 ± 10.73 μg h/ml) was significantly higher (p < 0.01) than the marketed tablet (27.41 ± 5.54 μg h/ml). The relative bioavailability (Fr) of the optimized felodipine-loaded microemulsion was about 308.3% higher than that of the marketed formulation. The results demonstrate that the prepared microemulsion is an advanced and efficient oral delivery system of felodipine for the management of hypertension.

Maternal docosahexaenoic acid (DHA, 22:6n-3) supplies the developing fetus during pregnancy; however, the mechanisms are unclear. We utilized pregnant rats to determine rates of DHA accretion, tissue unesterified DHA uptake and whole-body DHA synthesis-secretion. Female rats maintained on a DHA-free, 2% α-linolenic acid diet were either:1) sacrificed at 56 days for baseline measures, 2) mated and sacrificed at 14-18 days of pregnancy or 3) or sacrificed at 14-18 days as age-matched virgin controls. Maternal brain, adipose, liver and whole body fatty acid concentrations was determined for balance analysis, and kinetic modeling was used to determine brain and liver plasma unesterified DHA uptake and whole-body DHA synthesis-secretion rates. Total liver DHA was significantly higher in pregnant (95±5 μmol) versus non-pregnant (49±5) rats with no differences in whole-body DHA synthesis-secretion rates. However, liver uptake of plasma unesterified DHA was 3.8-fold higher in pregnant animals compared to non-pregnant controls, and periuterine adipose DHA was lower in pregnant (0.89±0.09 μmol/g) versus non-pregnant (1.26±0.06) rats. In conclusion, higher liver DHA accretion during pregnancy appears to be driven by higher unesterified DHA uptake, potentially via DHA mobilization from periuterine adipose for delivery to the fetus during the brain growth spurt., (Copyright © 2017 Elsevier Inc. All rights reserved.)

In this study, hyaluronan (HA) was grafted with alpha-linolenic acid (αLNA) by benzoyl mixed anhydrides methodology, which allowed the derivatization of HA under mild reaction conditions. The reaction was optimized and transferred from laboratory to semi-scale production. The derivative revealed an unexpected cytotoxicity after oven drying and storage at 40°C. For this reason, the storage conditions of sodium linolenyl hyaluronate (αLNA-HA) were optimized in order to preserve the beneficial effect of the derivative. Oven, spray dried and lyophilized samples were prepared and stored at -20°C, 4°C and 25°C up to 6 months. A comprehensive material characterization including stability study of the derivative, as well as evaluation of possible changes on chemical structure and presence of peroxidation products were studied by Nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), thermogravimetric analysis (TGA) and complemented with assessment of in vitro viability on mouse fibroblasts NIH-3T3. The most stable αLNA-HA derivative was obtained after spray drying and storage at ambient temperature under inert atmosphere. The choice of inert atmosphere is recommended to suppress oxidation of αLNA supporting the positive influence of the derivative on cell viability. The encapsulation of hydrophobic drugs of αLNA-HA were also demonstrated., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The origin of fatty acids in milk has not been elucidated in detail. We investigated the contribution of dietary α-linolenic acid (ALA) to human milk fat, its oxidation and endogenous conversion to long-chain polyunsaturated fatty acids. Ten lactating women were given (13)C-ALA orally, and breath and milk samples were collected for a five-day period, while dietary intakes were assessed. 37.5 ± 2.7 % (M ± SE) of the tracer was recovered in breath-CO2, and 7.3 ± 1.1 % was directly transferred into milk. About 0.25 % of the tracer was found in milk long-chain polyunsaturated fatty acids. Combining intake and milk data, we estimate that about 65 % of milk ALA is directly derived from maternal diet. Thus, the major portion of milk ALA is directly derived from the diet, but dietary ALA does not seem to contribute much as a precursor to milk n-3 long-chain polyunsaturated fatty acids within the studied time period.

To investigate the biodisponibility of placental transfer of fatty acids, rats pregnant for 20 days were given tracer amounts of [(14)C]palmitic (PA), oleic (OA), linoleic (LA), α-linolenic (LNA), or docosahexaenoic acid (DHA) orally and euthanized at 0.5, 1.0, 2.0, or 8.0 h thereafter. Maternal plasma radioactivity in lipids initially increased only to decline at later times. Most of the label appeared first as triacylglycerols (TAG); later, the proportion in phospholipids (PhL) increased. The percentage of label in placental lipids was also always highest shortly after administration and declined later; again, PhL increased with time. Fetal plasma radioactivity increased with time, with its highest value at 8.0 h after DHA or LNA administration. DHA initially appeared primarily in the nonesterified fatty acids (NEFA) and PA, OA, LA, and LNA as TAG followed by NEFA; in all cases, there was an increase in PhL at later times. Measurement of fatty acid concentrations allowed calculation of specific (radio)activities, and the ratio (fetal/maternal) of these in the plasmas gave an index of placental transfer activity, which was LNA > LA > DHA = OA > PA. It is proposed that a considerable proportion of most fatty acids transferred through the placenta are released into the fetal circulation in the form of TAG., (Copyright © 2016 the American Physiological Society.)

Stroke is a worldwide major cause of mortality and morbidity. Preclinical studies have identified over 1000 molecules with brain-protective properties. More than 200 clinical trials have evaluated neuroprotective candidates for ischemic stroke yet, to date almost all failed, leading to a re-analysis of treatment strategies against stroke. An emerging view is to seek combinatory therapy, or discovering molecules able to stimulate multiple protective and regenerative mechanisms. A pertinent experimental approach to identify such candidates is the study of brain preconditioning, which refers to how the brain protects itself against ischemia and others stress-inducing stimuli. The recent discovery that nutrients like alpha-linolenic acid (ALA is an essential omega-3 polyunsaturated fatty acid required as part of our daily diet), may be an efficient brain preconditionner against stroke fosters the novel concept of brain preconditioning by nutraceuticals. This review stresses the underestimated role of nutrition in preventing and combating stroke. Although there is a consensus that increased consumption of salt, fatty foods and alcoholic beverages may promote pathologies like hypertension, obesity and alcoholism - all of which are well known risk factors of stroke - few risk factors are attributed to a deficiency in an essential nutrient in the diet. The ALA deficiency observed in the Western modern diets may itself constitute a risk factor. This review outlines how ALA supplementation by modification of the daily diet prevented mortality and cerebral damage in a rodent model of ischemic stroke. It also describes the pleiotropic ability of ALA to trigger responses that are multicellular, mechanistically diverse, resulting in neuronal protection, stimulation of neuroplasticity, and brain artery vasodilation. Overall, this review proposes a promising therapeutic opportunity by integrating a nutritional-based approach focusing on enriching the daily diet in ALA to prevent the devastating damage caused by stroke., (Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Although there is extensive information describing the positive biological effects of conjugated linoleic acid and its main isomer rumenic acid (RA; C18:2 cis 9, trans 11), and alpha-linolenic acid (ALA) and vaccenic acid (TVA), data about their bioavailability are not available. In this work, we investigated the oral absorption and disposition of these fatty acids in Wistar rats. A naturally enriched goat dairy fat (EDF) was obtained by supplementing ruminant diets with oils or oilseeds rich in polyunsaturated fatty acids (PUFA). The EDF was administered orally (single dose of 3000 mg EDF/kg body weight equivalent to 153 mg TVA/kg body weight, 46 mg RA/kg body weight and 31 mg ALA/kg body weight), and serial blood and liver samples were collected and TVA, RA and ALA concentrations determined by GC/MS. The fatty acids TVA, RA and ALA were rapidly absorbed (t1/2a, 0.36, 0.66 and 0.76 h, respectively, for plasma) and slowly eliminated (t1/2β, 17.04, 18.40 and 16.52 h, respectively, for plasma). The maximum concentration (C max) was detected in liver > plasma > erythrocyte. Our study shows that when orally administered EDF, its components TVA, RA and ALA were rapidly absorbed and distributed throughout the body by the blood circulation to exert systemic effects.

Formulating healthy food rich in omega 3 fatty acids requires prior knowledge of the parameters influencing their bioavailability and their metabolic fate. In this context, we studied the effects of various emulsifiers widely used in the food industry, on the gastrointestinal lipolysis of flaxseed oil emulsions in an in vitro model and on the intestinal absorption and lymphatic secretion of alpha-linolenic acid (ALA) in rats. In vitro data showed that the emulsification of flaxseed oil with soya lecithin improved the gastric lipolysis of the oil (+30%), while the presence of Tween 80 or of sodium caseinate decreased it (-80% and -40%, respectively). The in vivo data demonstrated that the intestinal absorption and the lymphatic secretion of ALA were improved with soya lecithin (Cmax = 24 mg mL(-1)) and reduced in the presence of sodium caseinate (Cmax = 7 mg mL(-1)) compared to unemulsified flaxseed oil (Cmax = 16 mg mL(-1)); Tween 80 had no effect. In addition, the synthesized chylomicrons were notably larger and more numerous with soya lecithin whereas they were smaller in the presence of sodium caseinate (p < 0.05). This study shows that the intestinal bioavailability of ALA was increased by the emulsification of flaxseed oil with soya lecithin via an improved lipolysis, favouring the intestinal absorption of ALA and the secretion of many large chylomicrons in lymph.

Fatty acids are known to influence the ability of macrophages to generate reactive oxygen species (ROS). However the effect of elaidic acid (EA, 18:1 trans fatty acid) on ROS generation is not well studied. Rat peritoneal macrophages were enriched with elaidic acid by incubating the cells with 80 1M EA. The macrophages containing EA generated higher amounts of superoxide anion (O2*-), hydrogen peroxide (H2O2) and nitric oxide (NO) by 54, 123 and 237%, respectively as compared to control cells which did not contain EA. To study the competition of other C18 fatty acids with EA macrophages were incubated with EA along with stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and alpha-linolenic acid (ALA, 18:3). ALA significantly reduced the incorporation of EA into macrophage lipids. This also significantly reduced the generation of O2*-, H2O2, NO by macrophages. Studies were also conducted by feeding rats with diet containing partially hydrogenated vegetable fat (PHVF) as a source for EA and linseed oil (LSO) as a source for ALA. The rats were fed AIN-93 diet containing PHVF with 17% EA and incremental amounts of linseed oil for 10 weeks. The peritoneal macrophages from rats fed partially hydrogenated vegetable fat generated higher levels of O2*-, H2O2, NO by 46, 161 and 76% respectively, when compared to rats fed control diets containing ground nut oil. Macrophages from rats fed PHVF with incremental amounts of LSO produced significantly lower levels ROS in a dose dependent manner. Thus ALA reduces the higher levels of ROS generated by macrophages containing EA.

α-Linolenic acid (ALA), a carboxylic acid with 18 carbons and three cis double bonds, is an essential fatty acid needed for human health and can be acquired via regular dietary intake of foods that contain ALA or dietary supplementation of foods high in ALA, for example flaxseed. ALA has been reported to have cardiovascular-protective, anti-cancer, neuro-protective, anti-osteoporotic, anti-inflammatory, and antioxidative effects. ALA is the precursor of longer chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but its beneficial effects on risk factors for cardiovascular diseases are still inconclusive. The recommended intake of ALA for cardiovascular health is reported to be 1.1-2.2g/day. Although there are limited toxicological data for ALA, no serious adverse effects have been reported. The evidence on an increased prostate cancer risk in association with dietary ALA is not conclusive. Based on the limited data currently available, it may be concluded that ALA may be beneficial as a nutraceutical/pharmaceutical candidate and is safe for use as a food ingredient., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The purpose of this report was to demonstrate the effect of amphiphilic polysaccharides-based self-assembling micelles on enhancing the oral absorption of low molecular weight chondroitin sulfate (LMCS) in vitro and in vivo, and identify the transepithelial transport mechanism of LMCS micelles across the intestinal barrier. α-Linolenic acid-low molecular weight chondroitin sulfate polymers(α-LNA-LMCS) were successfully synthesized, and characterized by FTIR, (1)HNMR, TGA/DSC, TEM, laser light scattering and zeta potential. The significant oral absorption enhancement and elimination half-life (t₁/₂) extension of LNA-LMCS2 in rats were evidenced by intragastric administration in comparison with CS and LMCS. Caco-2 transport studies demonstrated that the apparent permeability coefficient (Papp) of LNA-LMCS2 was significantly higher than that of CS and LMCS (p<0.001), and no significant effects on the overall integrity of the monolayer were observed during the transport process. In addition, α-LNA-LMCS micelles accumulated around the cell membrane and intercellular space observed by confocal laser scanning microscope (CLSM). Furthermore, evident alterations in the F-actin cytoskeleton were detected by CLSM observation following the treatment of the cell monolayers with α-LNA-LMCS micelles, which further certified the capacity of α-LNA-LMCS micelles to open the intercellular tight junctions rather than disrupt the overall integrity of the monolayer. Therefore, LNA-LMCS2 with low cytotoxicity and high bioavailability might be a promising substitute for CS in clinical use, such as treating osteoarthritis, atherosclerosis, etc., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In the present study we evaluated the uptake of ALA and its conversion to EPA + DHA in rats given linseed oil (LSO) in native form or as a microemulsion in whey protein or in lipoid. In a single oral dose study in which rats maintained on rodent pellets deficient in ω-3 fatty acids were intubated with 0.35 g LSO in lipoid, the amount of ALA present in lymph was increased reaching a maximum concentration of 16.23 mg/ml at 2.5 h. The amount of ALA present in lymph was increased to a maximum level of 10.95 mg/ml at 4 h in rats given LSO as a microemulsion in whey protein. When LSO was given without emulsification, the amount of ALA present in lymph was found to reach a maximum level of 7.08 mg/ml at 6 h. A similar result was observed when weaning rats were intubated with 0.15 g of LSO per day for a period of 60 days. Higher levels of ALA by 41 and 103 % were observed in lymph lipids of rats given microemulsions of LSO in whey protein and in lipoid respectively as compared to rats given LSO without pre-emulsification. Very little conversion of ALA to EPA and DHA was observed in lymph lipids but higher amounts of EPA + DHA was observed in liver and serum of rats given LSO in microemulsion form. This study indicated that ALA concentration in lymph lipids was increased when LSO was given in microemulsion form in lipoid and further conversion to EPA and DHA was facilitated in liver and serum.

Flaxseed is a potent source of the n-3 fatty acid α-linolenic acid (ALA), yet most ALA is lost during ruminal biohydrogenation when ground flaxseed is fed to ruminants. Heat processing and urea formaldehyde condensation polymer (UFCP) treatment of flaxseed were investigated as possible means of protecting ALA from ruminal degradation. Ground flaxseed (GF), heated ground flaxseed (HGF), or UFCP-treated ground flaxseed (UFCPGF) were incubated for 0, 4, 8, and 12h in 4 ruminally cannulated multiparous lactating Holstein cows. Compared with GF, HGF and UFCPGF decreased ruminal disappearance of dry matter, crude protein, and ALA. Pepsin-digestible protein remaining after 12h of ruminal incubation was greater for UFCPGF and HGF than for GF. Twenty-four lactating Holstein cows (207 ± 37 d in milk, 668 ± 66 kg of body weight, and 1.33 ± 0.56 lactations) were then used in a randomized complete block design experiment with a basal feeding period to assess effects of flaxseed treatment on ALA enrichment of plasma and milk as well as lactational performance. No evidence existed that supplementation of HGF and UFCPGF affected dry matter intake, milk fat content, milk protein content, or energy-corrected milk yield, but UFCPGF marginally decreased milk yield compared with HGF. Plasma concentration of ALA was not affected by treatment. Concentrations of n-3 fatty acids and conjugated linoleic acids in milk fat were increased by UFCPGF relative to HGF, but ALA yield was not affected. Taken together, in situ results suggest that heat-treated flaxseed, with or without UFCP treatment, slowed ruminal disappearance of ALA. Feeding UFCP-treated flaxseed failed to alter ALA content of plasma or milk ALA yield relative to heating alone., (Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The bioavailability of α-linolenic acid (ALA) from flaxseed oil in an emulsified form v. a non-emulsified form was investigated by using two complementary approaches: the first one dealt with the characterisation of the flaxseed oil emulsion in in vitro gastrointestinal-like conditions; the second one compared the intestinal absorption of ALA in rats fed the two forms of the oil. The in vitro study on emulsified flaxseed oil showed that decreasing the pH from 7·3 to 1·5 at the physiological temperature (37°C) induced instantaneous oil globule coalescence. Some phase separation was observed under acidic conditions that vanished after further neutralisation. The lecithin used to stabilise the emulsions inhibited TAG hydrolysis by pancreatic lipase. In contrast, lipid solubilisation by bile salts (after lipase and phospholipase hydrolysis) was favoured by preliminary oil emulsification. The in vivo absorption of ALA in thoracic lymph duct-cannulated rats fed flaxseed oil, emulsified or non-emulsified, was quantified. Oil emulsification significantly favoured the rate and extent of ALA recovery as measured by the maximum ALA concentration in the lymph (Cmax = 14 mg/ml at 3 h in the emulsion group v. 9 mg/ml at 5 h in the oil group; P < 0·05). Likewise, the area under the curve of the kinetics was significantly higher in the emulsion group (48 mg × h/ml for rats fed emulsion v. 26 mg × h/ml for rats fed oil; P < 0·05). On the whole, ALA bioavailability was improved with flaxseed oil ingested in an emulsified state. Data obtained from the in vitro studies helped to partly interpret the physiological results.

Linoleic acid (18:2omega6) and alpha-linolenic acid (18:3omega3) represent the parent fats of the two main classes of polyunsaturated fatty acids: the omega-6 (n-6) and the omega-3 (n-3) fatty acids, respectively. Linoleic acid and alpha-linolenic acid both give rise to other long-chain fatty acid derivatives, including gamma-linolenic acid and arachidonic acid (omega-6 fatty acids) and docosahexaenoic acid and eicosapentaenoic acid (omega-3 fatty acids). These fatty acids are showing promise as safe adjunctive treatments for many skin disorders, including atopic dermatitis, psoriasis, acne vulgaris, systemic lupus erythematosus, nonmelanoma skin cancer, and melanoma. Their roles are diverse and include maintenance of the stratum corneum permeability barrier, maturation and differentiation of the stratum corneum, formation and secretion of lamellar bodies, inhibition of proinflammatory eicosanoids, elevation of the sunburn threshold, inhibition of proinflammatory cytokines (tumor necrosis factor-alpha, interferon-gamma, and interleukin-12), inhibition of lipoxygenase, promotion of wound healing, and promotion of apoptosis in malignant cells, including melanoma. They fulfill these functions independently and through the modulation of peroxisome proliferator-activated receptors and Toll-like receptors., (Copyright 2010 Elsevier Inc. All rights reserved.)

Diets rich in omega-3 polyunsaturated fatty acids are associated with decreased incidences of cardiovascular disease. The extent of incorporation and distribution of these beneficial fats into body tissues is uncertain. Rabbits were fed regular rabbit chow or a diet containing 10% ground flaxseed that is highly enriched with the omega-3 polyunsaturated fatty acid alpha-linolenic acid (ALA). The high-flaxseed diet resulted in an incorporation of ALA in all tissues, but mostly in the heart and liver with little in the brain. Docosahexaenoic and eicosapentaenoic acid levels were also selectively increased in some tissues, and the effects were not as large as ALA. Arachidonic acid and the ratio of omega-6/omega-3 fatty acids were decreased in all tissues obtained from the flax-supplemented group. Consumption of dietary flaxseed appears to be an effective means to increase ALA content in body tissues, but the degree will depend upon the tissues examined.

To elucidate if the trans-membrane uptake of fatty acids is protein-mediated, the uptake of oleic acid (18:1n-9), linoleic acid (18:2n-6), alpha-linolenic acid (18:3n-3), eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) was investigated in vitro in Atlantic salmon (Salmo salar L.) primary hepatocytes. Firstly, optimal fatty acid incubation time and concentration were established for trans-membrane 18:n-9 uptake. Based on saturation kinetics, a 2-h incubation time and 37.5 muM were used for the following experiments. Secondly, in order to identify whether trans-membrane fatty acid uptake in hepatocytes was mainly passive or protein mediated, hepatocytes were pre-incubated with membrane protein inhibitors followed by 2 h of incubation with [1-(14)C] labelled 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Fatty acid uptake into hepatocytes was highest with 20:5n-3 and 22:6n-3 and lowest with 18:1n-9. Phloretin was the most potent fatty acid uptake inhibitor, inhibiting uptake in the following order: 20:5n-3 > 18:3n-3 = 22:6n-3 > 18:2n-6 > 18:1n-9. The uptake of FA in Atlantic salmon hepatocytes seem to be due to both saturable and inhibitable protein mediated uptake, as well as passive uptake processes with more unsaturated and long fatty acids (20:n-3 > 22:6n-3 = 18:3n-3 > 18:2n-6) being more dependent on membrane protein mediated uptake compared to 18:1n-9.

There is little doubt regarding the essential nature of alpha-linolenic acid (ALA), yet the capacity of dietary ALA to maintain adequate tissue levels of long chain n-3 fatty acids remains quite controversial. This simple point remains highly debated despite evidence that removal of dietary ALA promotes n-3 fatty acid inadequacy, including that of docosahexaenoic acid (DHA), and that many experiments demonstrate that dietary inclusion of ALA raises n-3 tissue fatty acid content, including DHA. Herein we propose, based upon our previous work and that of others, that ALA is elongated and desaturated in a tissue-dependent manner. One important concept is to recognize that ALA, like many other fatty acids, rapidly undergoes beta-oxidation and that the carbons are conserved and reused for synthesis of other products including cholesterol and fatty acids. This process and the differences between utilization of dietary DHA or liver-derived DHA as compared to ALA have led to the dogma that ALA is not a useful fatty acid for maintaining tissue long chain n-3 fatty acids, including DHA. Herein, we propose that indeed dietary ALA is a crucial dietary source of n-3 fatty acids and its dietary inclusion is critical for maintaining tissue long chain n-3 levels.

Background: Dietary flaxseed may have beneficial cardiovascular effects. An aged population has a higher incidence of cardiovascular disease, but they may react differently to flaxseed in the diet., Objective: To investigate the response, over a period of 4 weeks, of subjects aged 18-29 or 45-69 years to a diet containing the same amount of alpha-linolenic acid (ALA) (6 g) introduced in the form of ground flaxseed (30 g) or flaxseed oil., Results: All subjects who received flaxseed oil showed a significant increase in plasma ALA and eicosapentaenoic acid (EPA) concentrations over the course of this study. Subjects who received ground flaxseed in the 18-29-year-old group showed a statistically significant increase in their plasma ALA levels, and although there was a trend in the same direction for the 45-69-year-old subjects, this did not achieve statistical significance. The diets induced no major changes in platelet aggregation, plasma total cholesterol, low-density lipoprotein or high-density lipoprotein cholesterol levels in any of the groups. Younger subjects showed a decrease in triglyceride (TG) values compared with older subjects. There were no significant side effects that caused compliancy issues., Conclusion: Subject age does not seem to be a major determining factor in influencing ALA absorption from a flaxseed-supplemented diet nor in the metabolism of ALA to EPA in the groups fed flaxseed oil. Concerns about side effects in older subjects administered a higher fiber load in a flaxseed-supplemented diet are not justified. However, younger but not older subjects showed a beneficial decrease in circulating TGs due to flaxseed supplementation.

Background: Dietary flaxseed may have significant health-related benefits due to its high content of the omega-3 fatty acid, alpha-linolenic acid (ALA). However, before extensive work can be undertaken in clinical populations to determine its efficacy, basic information on ALA bioavailability from flaxseed and the physiological effects of its ingestion need to be examined., Objective: The purpose of this study, therefore, was to determine the bioavailability of ALA when the flaxseed was ingested in the form of whole seed, milled seed or as flaxseed oil., Design: The flaxseed components (30 g of seed or 6 g of ALA in the oil) were baked into muffins for delivery over a 3 month test period in healthy male and female subjects., Results: Flaxseed ingestion over a 1 month period resulted in significant (P = 0.005) increases in plasma ALA levels in the flaxseed oil and the milled flaxseed supplemented groups. The former group had significantly (P = 0.004) higher ALA levels than the milled flaxseed group. The subjects supplemented with whole flaxseed did not achieve a significant (P > 0.05) increase in plasma ALA levels. An additional two months of flaxseed ingestion did not achieve significantly higher levels of plasma ALA in any of the groups. However, no significant increase was detected in plasma eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) levels in any of the flax-fed groups. There were no changes in plasma cholesterol or triglycerides or in platelet aggregation at any time point in any of the groups. Subjects in all of the groups exhibited some symptoms of gastro-intestinal discomfort during the early stages of the study but these disappeared in the oil and milled seed groups. However, compliance was a problem in the whole flaxseed group., Conclusion: In summary, ingestion of flax oil and milled flaxseed delivered significant levels of ALA to the plasma whereas whole flaxseed did not. Whole seed and oil preparations induced adverse gastrointestinal effects within 4 weeks and these were severe enough to induce the withdrawal of some subjects from these two groups. No one withdrew from the group that ingested milled flaxseed and, therefore, may represent a good form of flaxseed to avoid serious side-effects and still provide significant increases in ALA to the body.

Little is known about the uptake or metabolism of essential fatty acids (EFAs) in various mammalian organs. Thus, the distribution of deuterated alpha-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) and their metabolites was studied using a stable isotope tracer technique. Rats were orally administered a single dose of a mixture (20 mg each) of ethyl D5-18:3n-3 and D5-18:2n-6, and 25 tissues per animal were analyzed for D5-labeled PUFAs at 4, 8, 24, 96, 168, 240, 360, and 600 h after dosing. Plasma, stomach, and spleen contained the highest concentrations of labeled precursors at the earliest time points, whereas other internal organs and red blood cells reached their maximal concentrations at 8 h. The time-course data were consistent with liver metabolism of EFAs, but local metabolism in other tissues could not be ruled out. Brain, spinal cord, heart, testis, and eye accumulated docosahexaenoic acid with time, whereas skin accumulated mainly 20:4n-6. On average, approximately 16-18% of the D5-18:3n-3 and D5-18:2n-6 initial dosage was eventually accumulated in tissues, principally in adipose, skin, and muscle. Approximately 6.0% of D5-18:3n-3 and 2.6% of D5-18:2n-6 were elongated/desaturated and stored, mainly in muscle, adipose, and the carcass. The remaining 78% of both precursors was apparently catabolized or excreted.

We showed previously that alpha-eleostearic acid (alpha-ESA; 9Z11E13E-18:3) is converted to 9Z11E-conjugated linoleic acid (CLA) in rats through a Delta13-saturation reaction. To investigate this further, we examined the absorption and metabolism of alpha-ESA in rat intestine using a lipid absorption assay in lymph from the thoracic duct. In this study, we used 4 test oils [tung oil, perilla oil, CLA-triacylglycerol (TG), and pomegranate seed oil, containing alpha-ESA, alpha-linolenic acid (LnA; 9Z12Z15Z-18:3), CLA, and punicic acid (PA; 9Z11E13Z-18:3), respectively]. Emulsions containing the test oils were administered to rats, and lymph from the thoracic duct was collected over 24 h. The positional and geometrical isomerism of CLA produced by PA metabolism was determined using GC-electron impact (EI)-MS and (13)C-NMR, respectively; the product was confirmed to be 9Z11E-CLA. A part of alpha-ESA and PA was converted to 9Z11E-CLA 1 h after administration; therefore the lymphatic recoveries of alpha-ESA and PA were modified by the amount of recovered CLA. Cumulative recovery of CLA, alpha-ESA, and PA was lower than that of LnA only during h 1 (P < 0.05), and cumulative recovery of alpha-ESA and PA was significantly lower than that of LnA and CLA for 8 h (P < 0.05). Therefore, the absorption rate was LnA > CLA > alpha-ESA = PA. The conversion ratio of alpha-ESA to 9Z11E-CLA was higher than that of PA to 9Z11E-CLA over 24 h (P < 0.05). These results indicated that alpha-ESA and PA are slowly absorbed in rat intestine, and a portion of these fatty acids is quickly converted to 9Z11E-CLA.

The results of prospective cohort studies indicate that consuming fish or fish oil containing the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with decreased cardiovascular death, whereas consumption of the vegetable oil-derived n-3 fatty acid a-linolenic acid is not as effective. Randomized control trials (RCTs) in the context of secondary prevention also indicate that the consumption of EPA plus DHA is protective at doses <1 g/d. The therapeutic effect appears to be due to suppression of fatal arrhythmias rather than stabilization of atherosclerotic plaques. At doses >3 g/d, EPA plus DHA can improve cardiovascular disease risk factors, including decreasing plasma triacylglycerols, blood pressure, platelet aggregation, and inflammation, while improving vascular reactivity. Mainly on the basis of the results of RCTs, the American Heart Association recommends that everyone eat oily fish twice per week and that those with coronary heart disease eat 1 g/d of EPA plus DHA from oily fish or supplements. Directions for future research include (1) RCTs to confirm the initial trials showing that EPA plus DHA decreases cardiovascular death and additional studies to determine whether this effect is due to EPA, DHA, or the combination; the dosage of the effective components; and whether the mechanism of action in humans is prevention of fatal arrhythmias. (2) Clinical studies to determine whether the reduction in cardiovascular disease risk factors is due to EPA, DHA, or the combination and the dosage of the effective components. (3) Clinical studies to determine whether vegetable oil-derived alpha-linolenic acid added to a diet enriched in n-6 fatty acids can effectively substitute for fish oil-derived EPA plus DHA.

n-3 Fatty acids have important visual, mental, and cardiovascular health benefits throughout the life cycle. Biodistribution, interconversion, and dose response data are reviewed herein to provide a basis for more rational n-3 dose selections. Docosahexaenoic acid (DHA) is the principal n-3 fatty acid in tissues and is particularly abundant in neural and retinal tissue. Limited storage of the n-3 fatty acids in adipose tissue suggests that a continued dietary supply is needed. A large proportion of dietary alpha-linolenic acid (ALA) is oxidized, and because of limited interconversion of n-3 fatty acids in humans, ALA supplementation does not result in appreciable accumulation of long-chain n-3 fatty acids in plasma. Eicosapentaenoic acid (EPA) but not DHA concentrations in plasma increase in response to dietary EPA. Dietary DHA results in a dose-dependent, saturable increase in plasma DHA concentrations and modest increases in EPA concentrations. Plasma DHA concentrations equilibrate in approximately 1 mo and then remain at steady state throughout supplementation. DHA doses of approximately 2 g/d result in a near maximal plasma response. Both dietary DHA and EPA reduce plasma arachidonic acid concentrations. Tissue contents of DHA and EPA also increase in response to supplementation with these fatty acids. Human milk contents of DHA are dependent on diet, and infant DHA concentrations are determined by their dietary intake of this fatty acid. We conclude that the most predictable way to increase a specific long-chain n-3 fatty acid in plasma, tissues, or human milk is to supplement with the fatty acid of interest.

In contrast to humans, rats on a high-fat ketogenic diet seem incapable of maintaining plasma beta-hydroxybutyrate above 1 mmol/L for more than a week. Our goal was to determine whether fatty acid metabolism in rats changes despite the absence of sustained ketosis induced by the ketogenic diet. Fatty acid metabolism was assessed as changes in tissue fatty acid profiles and change in 13C-alpha-linolenic acid incorporation into plasma, liver, adipose tissue, and brain lipids. Despite loss of ketosis, the ketogenic diet reduced some polyunsaturated fatty acids in adipose tissue (up to 44%) and plasma (up to 90%) but raised polyunsaturates in liver triglycerides by up to 25-fold and raised arachidonic and docosahexaenoic acids in the brain by 15%. Lower tissue incorporation of 13C-alpha-linolenic acid but higher unlabeled and 13C-labeled docosahexaenoic acid in brain supports the view that the principal changes in fatty acid composition resulted from enhanced mobilization of polyunsaturates from adipose tissue to liver and brain. In the absence of sustained ketosis, changes in fatty acid metabolism resulting in an increase in brain polyunsaturates, particularly docosahexaenoic acid may, nevertheless, contribute to the seizure protection by the ketogenic diet.

An important question for mammalian nutrition is the relative efficiency of C18 versus C20 essential fatty acids (EFAs) for supporting the tissue composition of n-3 and n-6 pathway end products. One specific question is whether C22 EFAs are made available to tissues more effectively by dietary alpha-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) or by dietary eicosapentaenoic acid (20:5n-3) and dihomo-gamma-linolenic acid (20:3n-6). To address this question in a direct manner, four stable isotope compounds were given simultaneously in a novel paradigm. A single oral dose of a mixture of 2H5-18:3n-3, 13C-U-20:5n-3, 13C-U-18:2n-6, and 2H5-20:3n-6 was administered to rats given a defined diet. There was a preferential in vivo conversion of arachidonic acid (20:4n-6) to docosatetraenoic acid (22:4n-6) and of 22:4n-6 to n-6 docosapentaenoic acid (22:5n-6) when the substrates originated from the C18 precursors. However, when the end products docosahexaenoic acid (22:6n-3) or 22:5n-6 were expressed as the total amount in the plasma compartment divided by the dosage, this parameter was 11-fold greater for 20:5n-3 than for 18:3n-3 and 14-fold greater for 20:3n-6 than for 18:2n-6. Thus, on a per dosage basis, the total amounts of n-3 and n-6 end products accreted in plasma were considerably greater for C20 EFA precursors relative to C18.

The principal biological role of alpha-linolenic acid (alphaLNA; 18:3n-3) appears to be as a precursor for the synthesis of longer chain n-3 polyunsaturated fatty acids (PUFA). Increasing alphaLNA intake for a period of weeks to months results in an increase in the proportion of eicosapentaenoic acid (EPA; 20:5n-3) in plasma lipids, in erythrocytes, leukocytes, platelets and in breast milk but there is no increase in docosahexaenoic acid (DHA; 22:6n-3), which may even decline in some pools at high alphaLNA intakes. Stable isotope tracer studies indicate that conversion of alphaLNA to EPA occurs but is limited in men and that further transformation to DHA is very low. The fractional conversion of alphaLNA to the longer chain n-3 PUFA is greater in women which may be due to a regulatory effect of oestrogen. A lower proportion of alphaLNA is used for beta-oxidation in women compared with men. Overall, alphaLNA appears to be a limited source of longer chain n-3 PUFA in humans. Thus, adequate intakes of preformed long chain n-3 PUFA, in particular DHA, may be important for maintaining optimal tissue function. Capacity to up-regulate alphaLNA conversion in women may be important for meeting the demands of the fetus and neonate for DHA.

Background: Consumption of polyunsaturated fatty acids (PUFAs) may reduce coronary heart disease (CHD) risk, but n-6 PUFAs may compete with n-3 PUFA metabolism and attenuate benefits. Additionally, seafood-based, long-chain n-3 PUFAs may modify the effects of plant-based, intermediate-chain n-3 PUFAs. However, the interactions of these PUFAs in relation to CHD risk are not well established., Methods and Results: Among 45,722 men free of known cardiovascular disease in 1986, usual dietary intake was assessed at baseline and every 4 years by using validated food-frequency questionnaires. CHD incidence was prospectively ascertained. Over 14 years of follow-up, participants experienced 218 sudden deaths, 1521 nonfatal myocardial infarctions (MIs), and 2306 total CHD events (combined sudden death, other CHD deaths, and nonfatal MI). In multivariate-adjusted analyses, both long-chain and intermediate-chain n-3 PUFA intakes were associated with lower CHD risk, without modification by n-6 PUFA intake. For example, men with > or = median long-chain n-3 PUFA intake (> or =250 mg/d) had a reduced risk of sudden death whether n-6 PUFA intake was below (<11.2 g/d; hazard ratio [HR]=0.52; 95% confidence interval [CI]=0.34 to 0.79) or above (> or =11.2 g/d; HR=0.60; 95% CI=0.39 to 0.93) the median compared with men with a < median intake of both. In similar analyses, > or = median intake of intermediate-chain n-3 PUFAs (> or =1080 mg/d) was associated with a reduced total CHD risk whether n-6 PUFA intake was lower (HR=0.88; 95% CI=0.78 to 0.99) or higher (HR=0.89; 95% CI=0.79 to 0.99) compared with a < median intake of both. Intermediate-chain n-3 PUFAs were particularly associated with CHD risk when long-chain n-3 PUFA intake was very low (<100 mg/d); among these men, each 1 g/d of intermediate-chain n-3 PUFA intake was associated with an approximately 50% lower risk of nonfatal MI (HR=0.42; 95% CI=0.23 to 0.75) and total CHD (HR=0.53; 95% CI=0.34 to 0.83)., Conclusions: n-3 PUFAs from both seafood and plant sources may reduce CHD risk, with little apparent influence from background n-6 PUFA intake. Plant-based n-3 PUFAs may particularly reduce CHD risk when seafood-based n-3 PUFA intake is low, which has implications for populations with low consumption or availability of fatty fish.

Background: Maternal omega-3 fatty acid supplementation has been suggested to provide docosahexaenoic acid (DHA) for the normal brain development during gestation. DHA can be given as such (preformed) or through the omega-3 precursor alpha-linolenic acid (LNA) which is transformed into DHA by elongation and desaturation reactions. Western diet provides low amounts of LNA and DHA; therefore, supplementation with these omega-3 fatty acids has been suggested for pregnant women. However, the bioequivalence of LNA ingestion to DHA supplementation has not been established., Methods: Recently weaning female Wistar rats were fed a diet containing a small amount of LNA and no DHA. The animals were daily supplemented 40 days before mating, during pregnancy, and until delivery with 60 mg/kg of LNA or 6 mg/kg of DHA dissolved in coconut oil. Fatty acids were given as ethyl ester derivatives. Controls received coconut oil. The fatty acid composition of blood plasma, erythrocytes, liver, visceral adipose tissue, and brain segments (frontal cortex, hippocampus, and cerebellum) was analyzed. Brain segments obtained from 16- and 19-day-old fetuses and from 2- and 21-day-old rats were also analyzed for fatty acid composition., Results: Supplementation with LNA and DHA induced a similar accretion of DHA in plasma, erythrocytes, liver, and brain segments of the mothers. The adipose tissue showed a higher DHA accretion after DHA-supplementation. The DHA accretion in frontal cortex, hippocampus, and cerebellum obtained from the fetuses and the newborn rats was similar when the mothers were supplemented with LNA and DHA. Our results show that under our experimental conditions a similar accretion of DHA in the different tissues of the mothers and in the brain segments of fetuses and newborn rats is obtained after LNA and DHA supplementation., Conclusion: LNA and DHA, at the amounts given in this study, show a similar bioequivalence for DHA accretion in different tissues of the mother and in brain segments of fetuses and newborn rats., (Copyright 2004 S. Karger AG, Basel)

Increased dietary intake of fish oil omega-3 fatty acids, eicosapentanoic acid and docosohexanoic acid, and their precursor, alpha-linolenic acid (ALA), is associated with various health benefits. Enteric-coating (Entrox), which improves stability of omega-3 capsules, has been shown to facilitate fish oil absorption after chronic treatment. To assess the effect of Entrox coating on the short-term bioavailability of ALA administered in the form of ALA-rich Perilla seed oil, 12 healthy subjects (6 males and 6 females) received in a random order Entrox-coated and non-coated ALA formulations, each as a single 6g dose separated by a 3-week washout period. Measurements of plasma ALA concentrations from 0 to 24h showed no difference in ALA pharmacokinetics between the two formulations. However, significantly greater increases in plasma ALA levels from baseline to 24h were observed after ingestion of Entrox vs. non-coated product, suggesting a possible benefit of Entrox with long-term treatment.

The role of the placenta in controlling the supply of fatty acids to the fetus was investigated in term placentas from non-smokers (n 5), smokers (>ten cigarettes/d; n 5) and after addition of ethanol at 2 mg/ml (n 4). The maternal side was of the placenta was perfused ex vivo for 90 min with a physiological mixture of fatty acids and fatty acid:human albumin ratio. There was no effect of smoking on the transfer of linoleic (LA, 18: 2 n-6), alpha-linolenic (alphaLN, 18: 3 n-3), arachidonic (AA, 20: 4 n-6) or docosahexaenoic acid (DHA, 22: 6 n-3), expressed per perfused area (calculated from H2(18)O exchange). However, the presence of ethanol in the perfusate at a concentration of 2 mg/ml significantly reduced (P<0.01) the absolute rate of transfer of the two n-3 polyunsaturated fatty acids, alphaLN and DHA. This specific effect of ethanol on alphaLN and DHA also resulted in an altered selectivity for transfer of individual fatty acids. In the non-smoking control group the placenta selectively transferred polyunsaturated fatty acids to the fetus in the order DHA > AA > alphaLN > LA. The order of selectivity was unaltered in placentas from smokers, but the addition of ethanol to the perfusion medium altered the order of selectivity to AA > alphaLN > LA > DHA. The presence of ethanol in the perfusate was also associated with a significant reduction (P<0.05) in the clearance of H2(18)O. These results suggest that the presence of ethanol at a concentration of 2mg/ml may reduce the availability of polyunsaturated fatty acids to the developing fetus.

Animal and human studies have indicated that developing mammals fed only alpha-linolenic acid (18:3n-3) have lower docosahexaenoic acid (22:6n-3) content in brain and tissue phospholipids when compared with mammals fed 18:3n-3 plus 22:6n-3. The aim of this study was to test the hypothesis that low bioavailability of dietary 18:3n-3 to be converted to 22:6n-3 could partly explain this difference in fatty acid accretion. For that purpose, we determined the partitioning of dietary 18:3n-3 and 22:6n-3 between total n-3 fatty acid body accumulation, excretion, and disappearance (difference between the intake and the sum of total n-3 fatty acids accumulated and excreted). This was assessed using the quantitative method of whole-body fatty acid balance in growing rats fed the same amount of a 5% fat diet supplying either 18:3n-3 or 22:6n-3 at a level of 0.45% of dietary energy (i.e., 200 mg/100 g diet). We found that 58.9% of the total amount of 18:3n-3 ingested disappeared, 0.4% was excreted in feces, 21.2% accumulated as 18:3n-3 (50% in total fats and 46% in the carcass-skin compartment), and 17.2% accumulated as long-chain derivatives (14% as 22:6n-3 and 3.2% as 20:5n-3 + 22:5n-3). Similar results were obtained from the docosahexaenoate balance (as % of the total amount ingested): disappearance, 64.5%; excretion, 0.5%; total accumulation, 35% with 30.1% as 22:6n-3. Thus, rats fed docosahexaenoate accumulated a twofold higher amount of 22:6n-3, which was mainly deposited in the carcass-skin compartment (68%). Similar proportions of disappearance of dietary 18:3n-3 and 22:6n-3 lead us to speculate that these two n-3 polyunsaturated fatty acids were beta-oxidized in the same amount.

This article describes the application of in vivo 13C-nuclear magnetic resonance (NMR) spectroscopy and gas chromatography (GC)-combustion-isotope ratio mass spectrometry to the study of brain uptake and metabolism of polyunsaturated fatty acids in the suckling rat model. NMR spectroscopy is uniquely suited to the non-invasive detection of nonradioactive metabolites in living animals. We applied this approach to the noninvasive detection of 13C-arachidonate in brain and liver of living suckling rats but found that technical limitations in our model, mainly poor signal-to-noise, largely prevent useful results at this time. However, in a tracer study using simultaneous doses of 13C-gamma-linolenate and 13C-arachidonate, 13C-NMR of tissue lipid extracts quantitatively demonstrated a 10-fold greater (liver) or 17-fold greater (brain) accumulation of pre-formed vs newly synthesized arachidonate. GC-combustion-isotope ratio mass spectrometry was used to trace the utilization of [U-13C]-alpha-linolenate into three products in the brain: docosahexaenoate, cholesterol, and palmitate. The rationale was that although alpha-linolenate is used in de novo lipogenesis, the quantitative importance of this pathway is unknown. Our results in the suckling rat show that 2-13% of carbon from [U-13C]-alpha-linolenate appearing in brain lipids is in docosahexaenoate while the rest is in brain lipids synthesized de novo. Overall, these results indicate that the suckling rat brain prefers pre-formed to newly synthesized arachidonate and that alpha-linolenate is readily utilized in brain lipid synthesis. These methods are suited to comparative studies of the metabolism of polyunsaturates and they support previous observations that the metabolism of some polyunsaturates such as alpha-linolenate extends well beyond the traditional desaturation-chain elongation pathway.

The aim of this study was to evaluate the potential of an emulsion incorporating unsaturated fatty acids to improve the mucosal absorption of poorly absorbed drugs from rat intestinal loops in situ, using a water-in-oil-in-water (W/O/W) multiple emulsion. Vancomycin hydrochloride (VCM) was used as a model drug with low oral bioavailability. The entrapment efficiency of VCM in the emulsion was approximately 60% and remained constant over storage for 1 month at 4 degrees C. The emulsion incorporating C18 unsaturated fatty acids or docosahexaenoic acid (DHA) markedly enhanced VCM absorption after colonic and rectal dosing. The effectiveness of DHA on VCM colonic absorption improvement was the same as that of oleic acid, and less than that of linoleic and linolenic acids. For rectal dosing, bioavailability was similar among various emulsions, in the range 40-50%. The effect of the emulsion incorporating oleic acid or DHA on improving VCM enteral bioavailability was not increased proportional to the incorporated amount. The electrical resistance of membranes was not changed by the incorporation of various fatty acids in emulsions. Our results indicated that W/O/W emulsions incorporating C18 unsaturated fatty acid or DHA were useful carriers for improving the absorption of poorly absorbable drugs via the intestinal tract without gross changes to tight junction function., (Copyright 2000 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 89:1243-1252, 2000.)

Epidemiological studies have suggested that repeated weight cycling over time may increase the risk of coronary heart disease. The mechanism involved remains poorly understood, but the change in lipid metabolism during weight cycling has been offered as a possible explanation. The present study investigated the effect of weight cycling on the size and fatty acid composition of rat fat pads as well as serum cholesterol, triglyceride, glucose, insulin, and glucagon in rats. Two consecutive weight cycles were induced by 40% energy restriction followed by ad libitum refeeding of either a moderate-fat (MF; 22% energy) or a high-fat (HF; 45% energy) diet. The lipogenic enzymes, including fatty acid synthase, acetyl-CoA carboxylase, malic enzyme, pyruvate kinase, and lipoprotein lipase in the weight-cycled (WC) rats fed only the HF diet, yielded an overshoot of activities at the end of two weight cycles. These changes were accompanied by an 80% increase in the size of the adipocyte and a 40-50% increase in the size of perirenal and epididymal fat tissues in HF-WC rats. Regardless of whether the rats were fed the HF or MF diet, all WC rats showed a gradual reduction in linoleic and alpha-linolenic acid and an increase in palmitic, palmitoleic, and stearic acid in total body lipid. It is concluded that weight cycling in rats may promote body fatness if an HF diet is consumed and can significantly alter whole body fatty acid balance irrespective of whether they consumed an MF or HF diet. Most importantly, the weight cycling led to an overshoot or fluctuation of serum cholesterol, triglyceride, glucose, insulin, and glucagon. If weight cycling is associated with an increased risk of cardiovascular disease, then, part of the mechanism may involve the changes in these risk factors.

Increasing evidence supports the notion that there are significant differences in the health effects of diets enriched in saturated, as opposed to monounsaturated or polyunsaturated fat. However, the current understanding of how these types of fat differ in their handling by relevant tissues is incomplete. To examine the effects of fat type and nutritional status on the metabolic fate of dietary fat, we administered (14)C-labeled oleic, linolenic, or stearic acid with a small liquid meal to male Sprague-Dawley rats previously fasted for 15 h (fasted) or previously fed ad libitum (fed). (14)CO(2) production was measured for 8 h after tracer administration. The (14)C content of gastrointestinal tract, serum, liver, skeletal muscle (soleus, lateral, and medial gastrocnemius), and adipose tissue (omental, retroperitoneal, and epididymal) was measured at six time points (2, 4, 8, 24, and 48 h and 10 days) after tracer administration. Plasma levels of glucose, insulin, and triglyceride were also measured. Oxidation of stearic acid was significantly less than that of either linolenic or oleic acid in both the fed and fasted states. This reduction was in part explained by a greater retention of stearic acid within skeletal muscle and liver. Oxidation of oleate and stearate were significantly lower in the fed state than in the fasted state. In the fasted state, liver and skeletal muscle were quantitatively more important than adipose tissue in the uptake of dietary fat tracers during the immediate postprandial period. In contrast, adipose tissue was quantitatively more important than skeletal muscle or liver in the fed state. The movement of carbons derived from dietary fat between tissues is a complex time-dependent process, which varies in response to the type of fat ingested and the metabolic state of the organism.

The absorption and competition kinetics of the essential fatty acids (EFAs), linoleic acid (LA), alpha-linolenic acid (alphaLnA) and arachidonic acid (AA) in vivo were studied in the perfused rat jejunum. Uptake of each EFA on its own followed saturable kinetics at low luminal concentrations, suggesting a facilitative transport process, the affinity of which increased with chain length and degree of unsaturation. Absorption of one EFA was enhanced by low, whilst competitively inhibited by high, concentrations of a second EFA. Whereas LA and alphaLnA each interfered with the absorption of one another, both had little effect on AA. There was a strong inverse correlation between the relative unsaturation of an EFA and the change in Km of its absorption observed upon inhibition with another EFA. Overall, the results indicated a specific absorptive mechanism, probably involving a transport protein, the affinity of which increased with the degree of unsaturation of the EFA.

The effect of dietary docosahexaenoic acid (22:6n-3, DHA) on the metabolism of oleic, linoleic, and linolenic acids was investigated in male subjects (n = 6) confined to a metabolic unit and fed diets containing 6.5 or <0.1 g/d of DHA for 90 d. At the end of the diet period, the subjects were fed a mixture of deuterated triglycerides containing 18:1n-9[d6], 18:2n-6[d2], and 18:3n-3[d4]. Blood samples were drawn at 0, 2, 4, 6, 8, 12, 24, 48, and 72 h. Methyl esters of plasma total lipids, triglycerides, phospholipids, and cholesterol esters were analyzed by gas chromatography-mass spectrometry. Chylomicron triglyceride results show that the deuterated fatty acids were equally well absorbed and diet did not influence absorption. Compared to the low-DHA diet (LO-DHA), clearance of the labeled fatty acids from chylomicron triglycerides was modestly higher for subjects fed the high DHA diet (HI-DHA). DHA supplementation significantly reduced the concentrations of most n-6[d2] and n-3[d4] long-chain fatty acid (LCFA) metabolites in plasma lipids. Accumulation of 20:5n-3[d4] and 22:6n-3[d4] was depressed by 76 and 88%, respectively. Accumulations of 20:3n-6[d2] and 20:4n-6[d2] were both decreased by 72%. No effect of diet was observed on acyltransferase selectivity or on uptake and clearance of 18:1n-9[d6], 18:2n-6[d2], and 18:3n-3[d4]. The results indicate that accumulation of n-3 LCFA metabolites synthesized from 18:3n-3 in typical U.S. diets would be reduced from about 120 to 30 mg/d by supplementation with 6.5 g/d of DHA. Accumulation of n-6 LCFA metabolites synthesized from 18:2n-6 in U.S. diets is estimated to be reduced from about 800 to 180 mg/d. This decrease is two to three times the amount of n-6 LCFA in a typical U.S. diet. These results support the hypothesis that health benefits associated with DHA supplementation are the combined result of reduced accretion of n-6 LCFA metabolites and an increase in n-3 LCFA levels in tissue lipids.

Background: Essential fatty acid (EFA) requirements of patients receiving home parenteral nutrition (HPN) are uncertain., Objective: The objective was to evaluate the influence of the route of administration (enteral compared with parenteral) on plasma phospholipid EFA concentrations., Design: Intestinal absorption, parenteral supplement of EFAs, and plasma phospholipid EFA concentrations were investigated in balance studies in 4 groups (A, B, C, and D) of 10 patients with short-bowel syndrome and a fecal loss of >2000 kJ/d. Groups A (fat malabsorption <50%) and B (fat malabsorption >50%) did not receive HPN, whereas group C received HPN containing lipids (7.5 and 1.2 g/d linoleic and linolenic acids, respectively) and group D received fat-free HPN., Results: Intestinal absorption of linoleic and linolenic acids was 8.9 and 1.3 g/d and 2. 6 and 0.4 g/d in groups A and B, respectively, whereas EFA absorption was negligible in groups C and D. Thus, intestinal absorption of EFAs in group A corresponded to parenteral EFA supplements in group C, whereas group D was almost totally deprived of EFAs. The median plasma phospholipid concentration of linoleic acid decreased by 21.9%, >16.3%, >13.8%, 11.0%, and >7.7% and linolenic acid by 0.3%, 0.2%, 0.2%, >0.2%, and 0.1%, respectively, in 10 healthy control subjects and groups A, B, C, and D (P < 0.001)., Conclusions: Intestinally absorbed EFAs maintained plasma EFA status better than did an equal quantity of parenterally supplied EFAs. Intravenous requirements of EFAs in patients with negligible absorption of EFAs are probably higher than the amounts recommended to patients with preserved intestinal absorption of EFAs.

The dietary bioequivalence of alpha-linolenic (LNA) and docosahexaenoic acids (DHA) as substrates for brain and retinal n-3 fatty acid accretion during the brain growth spurt is reported for neonatal baboons who consumed a long-chain-polyunsaturate free commercial human infant formula with a n-6/n-3 ratio of 10:1. Neonates received oral doses of 13C-labeled fatty acids (LNA*) or (DHA*) at 4 wk of age, and at 6 wk brain (occipital cortex), retina, retinal pigment epithelium, liver, erythrocytes, and plasma were analyzed. In the brain, 1.71% of the preformed DHA* dose was detected, whereas 0.23% of the LNA* dose was detected as DHA*, indicating that preformed DHA is 7-fold more effective than LNA-derived DHA as a source for DHA accretion. In LNA*-dosed animals, DHA* was greater than 60% of labeled fatty acids in all tissues except erythrocytes, where docosapentaenoic acid was 55%. Estimates using dietary LNA levels as tracees indicate that brain turnover of DHA is less than 5% per week between weeks 4 and 6 of life. For retina and retinal pigment epithelium, preformed DHA was at levels 12-fold and 15-fold greater than LNA-derived DHA. Liver, plasma, and erythrocytes ratios were 27, 29, and 51, respectively, showing that these pools do not parallel tissue metabolism of a single dose of omega-3 fatty acids. The distributions of labeled fatty acids for LNA*-dosed animals were similar, in the order DHA > DPA > EPA > LNA, except for erythrocytes where docosapentaenoic acid predominated. These are the first direct measurements of the bioequivalence of DHA and LNA in neonatal primate brain and associated tissues.

The dietary bioequivalence during the brain growth spurt of alpha-linolenic (LNA) and docosahexaenoic acids (DHA) as substrates for brain and retinal n-3 fatty acid accretion is reported for the fetal baboons, whose mothers consumed a long chain polyunsaturate-free diet with a n-6/n-3 ratio of 10:1. Pregnant baboons received i.v. doses of U-13C-labeled fatty acids (LNA or DHA), plasma was collected from mother and fetus, and fetal brain (occipital cortex), retina, and liver were analyzed at various times post-dose. Fetal brain DHA plateaued 15-35 d post-dose with 1.6% of the preformed [U-13C-]DHA dose recovered in the brain. In contrast, LNA-derived DHA accretion also plateaued but was 20-fold lower. Liver and retinal results were of the same order of magnitude, but showed evidence of peaks and decline. Conversion products to n-3 long chain polyunsaturate were observed in the maternal circulation at 1 h after administration, as was transfer of both fatty acids to the fetus. From these measurements we estimate that a dietary level of about 0.45% of energy as LNA is sufficient to meet the requirements of the growing fetal brain, whereas 0.03% of energy as DHA would suffice. These data are the first direct measurements of the bioequivalence of DHA and LNA in developing primates and imply that n-3 fatty acid requirements for the developing fetal brain can be met by attainable dietary LNA for diets low in long chain polyunsaturates.