Dietary alpha-linolenic acid increases TNF-alpha, and decreases IL-6, IL-10 in response to LPS: effects of sesamin on the delta-5 desaturation of omega6 and omega3 fatty acids in mice

Trends and advances in pre- and post-harvest processing of linseed oil for quality food and health products

Linseed is an ancient crop used for diverse purposes since the beginning of civilization. In recent times, linseed has emerged as a superfood due to its high content of health-promoting omega-3 fatty acids and other bioactive compounds. Among primary health effects, it has potential to manage hypertension, diabetes, osteoporosis, atherosclerosis, cancer, arthritis, neurological, cardiovascular diseases including blood cholesterol levels, constipation, diarrhea, and autoimmune disorders etc. due to the presence of omega-3 fatty acid, lignans, high dietary fibers, and proteins, whereas, secondary health effects comprise of relieving from various skin disorders. Due to these health-beneficial properties, interest in linseed oil necessitates the intensification of research efforts on various aspects. These include cultivation technology, varietal and genetic improvement, post-harvest processing, profiling of nutrients and bioactive compounds, pre-clinical and clinical studies, etc. The present review discussed the advances in linseed research including pre- and post-harvest processing. However, focus on the bioactive compounds present in linseed oil and their health effects are also presented. Linseed cultivation, pre- and post-harvest processing aspects are covered including climatic, edaphic, agronomic factors, type of cultivar and storage conditions etc, which impact the overall oil yield and its nutritional quality. Various emerging applications of linseed oil in functional food, nutraceutical, pharmaceutical, and cosmeceutical preparations were also presented in detail. Further, recommendations were made on linseed oil research in the field of genetics, breeding germplasm resources and genome editing for exploring its full applications as a nutrition and health product.

Quality of Edible Sesame Oil as Obtained by Green Solvents: In Silico versus Experimental Screening Approaches

The present study aimed to investigate the qualitative and quantitative performance of five green solvents, namely 2-methyltetrahydrofuran (MeTHF), cyclopentyl methyl ether (CPME), p-cymene, d-limonene and ethanol to substitute n-hexane, for sesame seed oil extraction. In fact, both CPME and MeTHF gave higher crude yields than n-hexane (58.82, 54.91 and 50.84%, respectively). The fatty acid profile of the sesame seed oils remained constant across all the solvent systems, with a predominance of oleic acid (39.27-44.35%) and linoleic acid (38.88-43.99%). The total sterols gained the upmost amount with CPME (785 mg/100 g oil) and MeTHF (641 mg/100 g oil). CPME and MeTHF were also characterized by the optimum content of tocopherols (52.3 and 50.6 mg/100 g oil, respectively). The highest contents of total phenols in the sesame seed oils were extracted by CPME (23.51 mg GAE/g) and MeTHF (22.53 mg GAE/g) as compared to the other solvents, especially n-hexane (8 mg GAE/g). Additionally, sesame seed oils extracted by MeTHF and CPME also had the highest antioxidant and anti-inflammatory properties as compared to the other green solvents and n-hexane, encouraging their manufacturing use for sesame seed oil extraction.

Characterization of New Egyptian Linseed Varieties and the Effects of Roasting on Their Pigments, Tocochromanols, Phytosterols, Omega-3 Fatty Acids, and Stability

The purpose of this study was to explore the effects of roasting linseeds on the pigment, lipid profile, bioactive components, and oxidative stability of the extracted oils. The linseed varieties Giza 11, Giza 12, Sakha 3, and Sakha 6 were roasted at 180 °C for 10 min, and the oils were extracted by cold pressing. The results showed that, after roasting, there was an increase in oil percentage and peroxide value, as well as small increases in p-anisidine and acid values. Roasting also caused an increase in chlorophyll content, while lutein and β-carotene tend to slightly decrease, except in the Giza 11 variety. The total phenolics content was markedly enhanced after roasting. Omega-3 fatty acids were not affected by the roasting process. The total amounts of tocochromanol were found to decrease in the Giza 12 and Sakha 6 varieties after roasting. Plastochromanol-8 increased in all varieties after roasting. The phytosterol composition was minimally affected by roasting. Roasting enhanced the stability of the extracted oils, increasing the induction period and decreasing EC50 values. These results may thus help to discriminate between the different linseed varieties and serve to recommend the use of roasting to enhance the oxidative stability of extracted oil.

Lipidomics reveals the changes in lipid profile of flaxseed oil affected by roasting

Roasting before oil extraction improves the oxidative stability and odor of flaxseed oil; however, the effect of roasting on lipid profile is still unclear. Herein, the changes in lipid profile in flaxseed oil during roasting were investigated based on lipidomic approach. 238 lipids including fatty acid (45 species), phospholipid (37 species), triacylglycerol (125 species), and oxidized fatty acid (21 species) were determined in unroasted and roasted flaxseed oils. After roasting, unsaturated fatty acids including oleic, linoleic, and lenolenic acid decreased. Triacylglycerols such as TAG(18:3/18:3/18:3) and TAG(18:2/18:3/18:3) had the same change trends with unsaturated fatty acids. However, phosphatidylcholines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, lysophosphatidylcholines, lysophosphatidylethanolamines, and oxidized fatty acids firstly increased and then decreased during roasting. Cyclic phosphadic acids identified for the first time in flaxseed oils increased rapidly at high-temperature roasting. 23 lipids were determined as potential biomarkers to differentiate the light and dark roasted flaxseed oils. Our finding could provide useful information for flaxseed oil processing and lipidomics.

Bisphenol A-induced oxidative damage in the hepatic and cardiac tissues of rats: The modulatory role of sesame lignans

Bisphenol A (BPA) is an environmental pollutant that is widely produced throughout the world. It is primarily used in the manufacture of polycarbonate plastics, epoxy resins, paints and dental materials. BPA has been reported to promote hepatotoxicity and cardiotoxicity. The antioxidant activity of sesame lignans is well established. The current study assessed the protective efficiency of sesame lignans against BPA-induced hepatotoxicity and cardiotoxicity. Rats were divided into 4 groups: A control group, a BPA-treated group, a sesame lignans-treated group and a sesame lignans and BPA-treated group. Rats were orally administered their respective doses daily [30 mg/kg body weight (BW) BPA and/or 20 mg/kg BW sesame lignans] for 6 weeks. Liver function tests were performed using serum of all groups. Lipid profile and antioxidant status were also measured in liver tissue of the studied groups. The results were confirmed by histopathological examination of liver and heart tissues. The oral administration of BPA was revealed to elicit significant decreases in the activities of hepatic glutathione peroxidase, glutathione reductase, superoxide dismutase and glutathione. It also significantly increased levels of malondialdehyde. Furthermore, BPA-treatment resulted in lipid accumulation, elevated activities of alanine aminotransferase, creatine kinase MB and lactate dehydrogenase, and histological changes of liver and heart tissues. However, the co-administration of sesame lignans and BPA attenuated hepatotoxicity, cardiotoxicity and BPA-induced histological changes. The results of the current study indicated that sesame lignans may be helpful in the development of novel natural drugs to treat hepatic and cardiovascular disorders.

Analysis of plasma metabolic profiling and evaluation of the effect of the intake of Angelica keiskei using metabolomics and lipidomics

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica keiskei contains many bioactive components with anti-oxidative and anti-inflammatory effects. It is also effective for the treatment of diabetes mellitus, hypertension, and arteriosclerosis, but the relationships between these effects and the active components in the herb have not been studied.

AIM OF THE STUDY

We aimed to confirm the effects of Angelica keiskei on humans.

MATERIALS AND METHODS

A metabolomics and lipidomics study was performed using human plasma samples from 20 subjects after the intake of Angelica keiskei, and the components of Angelica keiskei in the plasma were profiled. UPLC-Orbitrap-MS was used to analyze the plasma and plant extracts, and multivariate analysis and correlation studies between the exogenous components from plant and endogenous metabolite in plasma were performed.

RESULTS

The levels of the 14 metabolites including kynurenic acid, prostaglandin E1, chenodeoxycholic acid, lysoPC (18:1), lysoPC (18:2), lysoPC (20:3), lysoPC (20:4), lysoPC (22:6), PC (34:1), PC (34:2), PC (38:3), PC (38:4), PC (38:6) and PC (40:7) in the plasma were changed. By monitoring the components originating from Angelica keiskei in plasma, five components including 5-methoxypsoralen, 8-methoxypsoralen, 4-hydroxyderricin, xanthoangelol B and xanthoangelol F were detected and they reduced the levels of bile acids and fatty acids.

CONCLUSIONS

The levels of the metabolites, including bile acids, amino acids, glycerophospholipids and fatty acids, in the plasma were changed, and 14 significantly changed metabolites were closely related to the preventive effect against liver diseases, type 2 diabetes, anemia, obesity, atherosclerosis, depression and anti-inflammatory effects. The five components of Angelica keiskei were related the modulatory activity of reducing the levels of bile acids and fatty acids.

Promising pain-relieving activity of an ancient Persian remedy (mixture of white Lily in sesame oil) in patients with chronic low back pain

Background and Objectives:

Chronic low back pain (CLBP) is one the frequent musculoskeletal issues among adults mostly without a specific etiology. In this study, we investigated a traditional Persian remedy for back pain which is based on topical application of a mixture of sesame oil (SO) and white lily (LSM).

Materials and Methods:

The chemical profile, phenol content, and antioxidant activity of the herbal samples were determined using GC-MS, total phenol content (TPC) assay, and DPPH assay, respectively. Clinical efficacy of the herbal samples by a double-blind placebo was examined.

Results:

TPC of SO and LSM was 45 ± 5.7 and 68.3 ± 11.2 mg GAE/g oil mixture, respectively. The SO could inhibit 59.7% of free radicals, whereas LSM showed a radical inhibition rate of 74.7% in DPPH assay. LSM could reduce the pain feeling and obtained the lowest pain scores (Oswestry disability index and numeric rating scale) in weeks 4 and 8 of therapy in comparison to other treatment groups (diclofenac gel and SO) and placebo control (Vaseline).

Conclusions:

The results implicate the LSM as a novel therapeutic alternative for the therapy of the CLBP.

Neuroprotective Effect of Alpha-Linolenic Acid against Aβ-Mediated Inflammatory Responses in C6 Glial Cell

Therapeutic approaches for neurodegeneration, such as Alzheimer's disease (AD), have been widely studied. One of the critical hallmarks of AD is accumulation of amyloid beta (Aβ). Aβ induces neurotoxicity and releases inflammatory mediators or cytokines through activation of glial cell, and these pathological features are observed in AD patient's brain. The purpose of this study is to investigate the protective effect of alpha-linolenic acid (ALA) on Aβ_25-35-induced neurotoxicity in C6 glial cells. Exposure of C6 glial cells to 50 μM Aβ_25-35 caused cell death, overproduction of nitric oxide (NO), and pro-inflammatory cytokines release [interleukin (IL)-6 and tumor necrosis factor-α], while treatment of ALA increased cell viability and markedly attenuated Aβ_25-35-induced excessive production of NO and those inflammatory cytokines. Inhibitory effect of ALA on generation of NO and cytokines was mediated by down-regulation of inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expressions. In addition, ALA treatment inhibited reactive oxygen species generation induced by Aβ_25-35 through the enhancement of the nuclear factor-erythroid 2-related factor-2 (Nrf-2) protein levels and subsequent induction of heme-oxygenase-1 (HO-1) expression in C6 glial cells dose- and time-dependently. Furthermore, the levels of neprilysin and insulin-degrading enzyme protein expressions, which contribute to degradation of Aβ, were also increased by treatment of ALA compared to Aβ_25-35-treated control group. In conclusion, effects of ALA on Aβ degradation were shown to be mediated through inhibition of inflammatory responses and activation of antioxidative system, Nrf-2/HO-1 signaling pathway, in C6 glial cells. Our findings suggest that ALA might have the potential for therapeutics of AD.

Effects of Dietary Supplementation of Astaxanthin and Sesamin on Daily Fatigue: A Randomized, Double-Blind, Placebo-Controlled, Two-Way Crossover Study

Severe fatigue can negatively affect quality of life, and oxidative stress may play a role in its mechanism. The aim of this study was to evaluate the effect of dietary supplementation of astaxanthin and sesamin (AS), strong food-derived antioxidants, on fatigue. Twenty-four healthy volunteers were supplemented with AS and placebo, each for four weeks. After each supplementation period, participants underwent tasks inducing mental and physical fatigue (visual display terminal task and ergometer task, respectively). Subjective fatigue was evaluated using a visual analogue scale during and after the mental and physical tasks, and daily subjective fatigue was evaluated by the Chalder fatigue questionnaire. Secondary outcomes included other subjective feelings, work efficiency, autonomic nerve activity, levels of an oxidative stress marker (plasma phosphatidylcholine hydroperoxide (PCOOH)) and safety. AS supplementation was associated with significantly improved recovery from mental fatigue compared with placebo. Increased PCOOH levels during mental and physical tasks were attenuated by AS supplementation. No differences between AS and placebo were detected in secondary outcomes, and no adverse effects of AS supplementation were observed. In conclusion, AS supplementation may be a candidate to promote recovery from mental fatigue which is experienced by many healthy people.

Dietary linoleic acid intake and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The aim of the present study was to investigate the effect of increasing dietary linoleic acid (LA) intake on the blood concentrations of inflammatory markers including cytokines, acute phase reactants and adhesion molecules in adults.

METHODS

We comprehensively searched PubMed, Embase and Cochrane Library for eligible studies. Overall, 30 randomized controlled studies involving 1377 subjects were included for meta-analysis.

RESULTS

No significant effect of higher LA intake was observed for cytokines: tumor necrosis factor (SMD: -0.01; 95% CI: -0.19 to 0.17), interleukin-6 (SMD: 0.11, 95% CI: -0.07 to 0.29), adiponectin (SMD: 0.17, 95% CI: -0.17 to 0.50) and monocyte chemoattractant protein 1 (SMD: 0.14, 95% CI: -0.33 to 0.60). Pooled effect size from 16 studies showed that the C-reactive protein (CRP) concentration was not significantly affected by increasing LA intake (SMD = 0.09, 95% CI: -0.05 to 0.24). However, subgroup and meta-regression analysis suggested that in subjects with a more profound increase of dietary LA intake, LA might increase the blood CRP level. Other acute phase reactants including fibrinogen and plasminogen activator inhibitor-1 and adhesion molecules were not significantly changed when LA was increased in diet. No significant heterogeneity or publication bias was observed, although only a limited number of eligible studies were included for some markers.

CONCLUSION

Our meta-analysis suggested that increasing dietary LA intake does not have a significant effect on the blood concentrations of inflammatory markers. However, the extent of change in dietary LA intake might affect the effect of LA supplementation on CRP.

The Role of Essential Fatty Acids in Anorexia Nervosa and Obesity

The two basic questions in food intake study are what we eat, and how much do we eat. Most research is directed toward the control of how much is eaten. This is likely the result of the increased number of individuals with eating disorders in the Western world. Feeding behavior is highly complex, and is controlled by many psychological, physiological, biochemical, and immunological factors. The aim of this review is to clarify the involvement of fatty acids in eating disorders such as anorexia and binge eating disorder. The review will describe the modified fatty acid profile observed in individuals with anorexia or binge eating disorder, and discuss on what factors fatty acids can exert beneficial effects. In addition, the differences and similarities between anorexia and binge eating disorder will be discussed. We suggest that beneficial effects of essential fatty acids on both anorexia and binge eating disorder can be explained by the stabilizing effect of those fatty acids on the neuronal membrane fluidity index.

Sesamin attenuates allergic airway inflammation through the suppression of nuclear factor-kappa B activation

The aim of the present study is to determine the role of sesamin, the most abundant lignan in sesame seed oil, on the regulation of allergic airway inflammation in a murine asthma model. A BALB/c mouse model with allergic asthma was used to evaluate the effects of sesamin on nuclear factor-kappa B (NF-κB) activation. An enzyme-linked immunosorbent assay was used to determine protein expression in bronchoalveolar lavage (BAL) fluids. Hematoxylin and eosin staining was performed to examine histological changes. Moreover, western blot analysis was used to detect the expression of proteins in tissues. Prior to administering sesamin, the mice developed the following pathophysiological features of asthma: An increase in the number of inflammatory cells, increased levels of interleukin (IL)-4, IL-5 and IL-13, decreased levels of interferon-γ in BAL fluids and lung tissues, increased immunoglobulin E (IgE) levels in the serum and an increased activation of NF-κB in lung tissues. Following treatment with sesamin, the mice had evidently reduced peribronchiolar inflammation and airway inflammatory cell recruitment, inhibited production of several cytokines in BAL fluids and lung tissues, and decreased IgE levels. Following inhalation of ovalbumin, the administration of sesamin also inhibited the activation of NF-κB. In addition, sesamin administration reduced the phosphorylation of p38 mitogen-activated protein kinases (MAPKs). The present study demonstrates that sesamin decreases the activation of NF-κB in order to attenuate allergic airway inflammation in a murine model of asthma, possibly via the regulation of phosphorylation of p38 MAPK. These observations provide an important molecular mechanism for the potential use of sesamin in preventing and/or treating asthma, as well as other airway inflammatory disorders.

Concentration and ratio of essential fatty acids influences the inflammatory response in lipopolysaccharide challenged mice

The goal of this study was to evaluate the role of both the % of dietary, 18-carbon PUFA (2.5%, 5% and 10%) and the n-6:n-3 ratio (1:1, 10:1 and 20:1) on the acute inflammatory response. Mice were fed diets for 8 weeks and injected intraperitoneally with LPS to induce acute inflammation. After 24h mice were sacrificed and plasma cytokines measured. Diets significantly affected the erythrocyte PUFA composition and the effect of PUFA ratio was more prominent than of PUFA concentration. The % dietary PUFA affected feed efficiency (p<0.05) and there was a PUFA×ratio interaction with body fat (p<0.01). In mice fed high %kcal from PUFA, those given a low n-6:n-3 ratio had more body fat than those fed a high ratio. Of the twelve cytokines measured, eleven were significantly affected by the % PUFA (p<0.05), whereas five were affected by the ratio (p<0.05). For seven cytokines, there was a significant PUFA×ratio interaction according to a two way ANOVA (p<0.05). These data indicate that dietary polyunsaturated fatty acids can affect LPS induced-inflammation.

Mechanisms of enhanced insulin secretion and sensitivity with n-3 unsaturated fatty acids

The widespread acceptance that increased dietary n-3 polyunsaturated fatty acids (PUFAs), especially α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), improve health is based on extensive studies in animals, isolated cells and humans. Visceral adiposity is part of the metabolic syndrome, together with insulin resistance, dyslipidemia, hypertension and inflammation. Alleviation of metabolic syndrome requires normalization of insulin release and responses. This review assesses our current knowledge of the mechanisms that allow n-3 PUFAs to improve insulin secretion and sensitivity. EPA has been more extensively studied than either ALA or DHA. The complex actions of EPA include increased G-protein-receptor-mediated release of glucagon-like peptide 1 (GLP-1) from enteroendocrine L-cells in the intestine, up-regulation of the apelin pathway and down-regulation of other control pathways to promote insulin secretion by the pancreatic β-cells, together with suppression of inflammatory responses to adipokines, inhibition of peroxisome proliferator-activated receptor α actions and prevention of decreased insulin-like growth factor-1 secretion to improve peripheral insulin responses. The receptors involved and the mechanisms of action probably differ for ALA and DHA, with antiobesity effects predominating for ALA and anti-inflammatory effects for DHA. Modifying both GLP-1 release and the actions of adipokines by n-3 PUFAs could lead to additive improvements in both insulin secretion and sensitivity.

Characterization and Analysis of Sesamolinol Diglucoside in Sesame Seeds

A new lignan glucoside was isolated from defatted sesame seed flour and its structure was established as sesamolinol diglucoside [2-(3-methoxy-4-(O-beta-D-glucopyranosyl (1-->6)-O-beta-D-glucopyranoside)phenoxyl)-6-(3,4-methylenedioxyphenyl)-cis-3,7-dioxabicyclo-(3.3.0)-octane] by mass and nuclear magnetic resonance spectroscopy. A quantitative analysis of 65 sesame seed samples showed that this sesamolinol diglucoside ranged from <5 to 232 mg/100 g of seeds (98+/-57 mg/100 g) with no difference between white and black sesame seeds.

Lipid metabolic dose response to dietary alpha-linolenic acid in monk parrot (Myiopsitta monachus)

Monk parrots (Myiopsitta monachus) are susceptible to atherosclerosis, a progressive disease characterized by the formation of plaques in the arteries accompanied by underlying chronic inflammation. The family of n-3 fatty acids, especially eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), have consistently been shown to reduce atherosclerotic risk factors in humans and other mammals. Some avian species have been observed to convert α-linolenic acid (18:3n-3, ALA) to EPA and DHA (Htin et al. in Arch Geflugelk 71:258-266, 2007; Petzinger et al. in J Anim Physiol Anim Nutr, 2013). Therefore, the metabolic effects of including flaxseed oil, as a source of ALA, in the diet at three different levels (low, medium, and high) on the lipid metabolism of Monk parrots was evaluated through measuring plasma total cholesterol (TC), free cholesterol (FC), triacylglycerols (TAG), and phospholipid fatty acids. Feed intake, body weight, and body condition score were also assessed. Thus the dose and possible saturation response of increasing dietary ALA at constant linoleic acid (18:2n-6, LNA) concentration on lipid metabolism in Monk parrots (M. monachus) was evaluated. Calculated esterified cholesterol in addition to plasma TC, FC, and TAG were unaltered by increasing dietary ALA. The high ALA group had elevated levels of plasma phospholipid ALA, EPA, and docosapentaenoic acid (DPAn-3, 22:5n-3). The medium and high ALA groups had suppressed plasma phospholipid 20:2n-6 and adrenic acid (22:4n-6, ADA) compared to the low ALA group. When the present data were combined with data from a previous study (Petzinger et al. in J Anim Physiol Anim Nutr, 2013) a dose response to dietary ALA was observed when LNA was constant. Plasma phospholipid ALA, EPA, DPAn-3, DHA, and total n-3 were positively correlated while 20:2n-6, di-homo-gamma-linoleic acid (20:3n-6Δ7), arachidonic acid (20:4n-6), ADA, and total n-6 were inversely correlated with dietary en% ALA.

Nrf2 deletion causes "benign" simple steatosis to develop into nonalcoholic steatohepatitis in mice fed a high-fat diet

Background

Nonalcoholic fatty liver disease begins with the aberrant accumulation of triglyceride in the liver. Its spectrum includes the earliest stage of hepatic simple steatosis (SS), nonalcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma. Generally, hepatic SS is often self-limited; however 10%-30% of patients with hepatic SS progress to NASH. The cause(s) of the transition from SS to NASH are unclear. We aimed to test the contribution of nuclear erythroid 2-related factor 2 (Nrf2) on the progression of “benign” SS to NASH in mice fed a high fat diet. In doing so, we discovered the influence of fatty acid in that progression.

Method

The involvement of Nrf2 in defending against the development of NASH was studied in an experimental model induced by a high-fat diet. Wild-type and Nrf2-null mice were fed the diet. Their specimens were analyzed for pathology as well as for fatty acid content and ratios.

Result

In feeding the high-fat diet to the Wild-type and the Nrf2-null mice, the Wild-type mice increased hepatic fat deposition without inflammation or fibrosis (i.e., simple steatosis), while the Nrf2-null mice had significantly more hepatic steatosis and substantial inflammation, (i.e., nonalcoholic steatohepatitis). In addition, as a result of the high-fat diet, SFA (C20: 0, C22: 0) and MUFA (C18: 1, C20: 1) content in Nrf2-null mice were significantly higher than in Wild-type mice. In the Nrf2-null mice the PUFA/TFA ratio decreased; conversely, the MUFA/TFA ratio increased.

Conclusion

The deletion of Nrf2 causes “benign” SS to develop into NASH in mice fed with a high-fat diet, through prompt fatty acid accumulation and disruption of hepatic fatty acid composition in the liver.

Effect of n-3 and n-6 unsaturated fatty acids on prostate cancer (PC-3) and prostate epithelial (RWPE-1) cells in vitro

Prostate cancer (PCa) is one of the leading causes of death in the elderly men. Polyunsaturated fatty acids (PUFAs) regulate proliferation of cancer cells. In the present study, we evaluated the effect of various PUFAs on the proliferation and survival of human prostate cancer (PC-3) and human prostate epithelial (RWPE-1) cells in vitro.

LA, GLA, AA, ALA, EPA and DHA (linoleic acid, gamma-linolenic acid, arachidonic acid, alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid respectively) when tested at 50, 100, 150, and 200 μM inhibited proliferation of RWPE-1 and PC-3 cells, except that lower concentrations of LA (25 μM) and GLA (5, 10 μM) promoted proliferation. Though all fatty acids tested produced changes in the production of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), lipoxin A₄ and free radical generation by RWPE-1 and PC-3 cells, there were significant differences in their ability to do so. As expected, supplementation of various n-3 and n-6 fatty acids to RWPE-1 and PC-3 cells enhanced the content of the added fatty acids and their long-chain metabolites in these cells. In contrast to previous results, we did not find any direct correlation between inhibition of cell proliferation induced by various fatty acids and free radical generation. These results suggest that polyunsaturated fatty acids suppress proliferation of normal and tumor cells by a variety of mechanisms that may partly depend on the type(s) of cell(s) being tested and the way these fatty acids are handled by the cells. Hence, it is suggested that more deeper and comprehensive studies are needed to understand the actions of fatty acids on the growth of normal and tumor cells.

Conversion of α-linolenic acid to long-chain omega-3 fatty acid derivatives and alterations of HDL density subfractions and plasma lipids with dietary polyunsaturated fatty acids in Monk parrots (Myiopsitta monachus)

The effect of α-linolenic acid from a flaxseed (FLX)-enriched diet on plasma lipid and fatty acid metabolism and possible atherosclerosis risk factors was studied in Monk parrots (Myiopsitta monachus). Twenty-four Monk parrots were randomly assigned to diets containing either 10% ground SUNs or 10% ground FLXs. Feed intake was calculated daily. Blood samples, body condition scores and body weights were obtained at -5 weeks, day 0, 7, 14, 28, 42 and 70. Plasma samples were analysed for total cholesterol, free cholesterol, triacylglycerols and lipoproteins. Phospholipid subfraction fatty acid profiles were determined. By day 70, the FLX group had significantly higher plasma phospholipid fatty acids including 18:3n-3 (α-linolenic acid), 20:5n-3 (eicosapentaenoic acid) and 22:6n-3 (docosahexaenoic acid). The sunflower group had significantly higher plasma phospholipid levels of 20:4n-6 (arachidonic acid). By day 70, the high-density lipoprotein (HDL) peak shifted resulting in significantly different HDL peak densities between the two experimental groups (1.097 g/ml FLX group and 1.095 g/ml SUN group, p = 0.028). The plasma fatty acid results indicate that Monk parrots can readily convert α-linolenic acid to the long-chain omega-3 derivatives including docosahexaenoic acid and reduce 20:4n-6 accumulation in plasma phospholipids. The reason for a shift in the HDL peak density is unknown at this time.

Chondroprotective and anti-inflammatory effects of sesamin

Osteoarthritis (OA) is a major disability of elderly people. Sesamin is the main compound in Sesamun indicum Linn., and it has an anti-inflammatory effect by specifically inhibiting Δ5-desaturase in polyunsaturated fatty acid biosynthesis. The chondroprotective effects of sesamin were thus studied in a porcine cartilage explant induced with interleukin-1beta (IL-1β) and in a papain-induced osteoarthritis rat model. With the porcine cartilage explant, IL-1β induced release of sulfated-glycosaminoglycan (s-GAG) and hydroxyproline release, and this induction was significantly inhibited by sesamin. This ability to inhibit these processes might be due to its ability to decrease expression of MMP-1, -3 and -13, which can degrade both PGs and type II collagen, both at the mRNA and protein levels. Interestingly, activation of MMP-3 might also be inhibited by sesamin. Moreover, in human articular chondrocytes (HACs), some pathways of IL-1β signal transduction were inhibited by sesamin: p38 and JNK. In the papain-induced OA rat model, sesamin treatment reversed the following pathological changes in OA cartilage: reduced disorganization of chondrocytes in cartilage, increased cartilage thickness, and decreased type II collagen and PGs loss. Sesamin alone might increase formation of type II collagen and PGs in the cartilage tissue of control rats. These results demonstrate that sesamin efficiently suppressed the pathological processes in an OA model. Thus, sesamin could be a potential therapeutic strategy for treatment of OA.

A diet enriched in docosahexanoic Acid exacerbates brain parenchymal extravasation of apo B lipoproteins induced by chronic ingestion of saturated fats

Chronic ingestion of saturated fatty acids (SFAs) was previously shown to compromise blood-brain barrier integrity, leading to brain parenchymal extravasation of apolipoprotein B (apo B) lipoproteins enriched in amyloid beta. In contrast, diets enriched in mono- or polyunsaturated (PUFA) oils had no detrimental effect. Rather, n3 and n6 oils generally confer protection via suppression of inflammation. This study investigated in wild-type mice if a PUFA diet enriched in docosahexanoic acid (DHA) restored blood-brain barrier integrity and attenuated parenchymal apo B abundance induced by chronic ingestion of SFA. Cerebrovascular leakage of apo B was quantitated utilising immunofluorescent staining. The plasma concentration of brain-derived S100β was measured as a marker of cerebrovascular inflammation. In mice fed SFA for 3 months, provision thereafter of a DHA-enriched diet exacerbated parenchymal apo B retention, concomitant with a significant increase in plasma cholesterol. In contrast, provision of a low-fat diet following chronic SFA feeding had no effect on SFA-induced parenchymal apo B. The findings suggest that in a heightened state of cerebrovascular inflammation, the provision of unsaturated fatty acids may be detrimental, possibly as a consequence of a greater susceptibility for oxidation.

Sesamin Induces Human Leukemic Cell Apoptosis via Mitochondrial and Endoplasmic Reticulum Stress Pathways

Background

Sesamin is a purified compounds extracted from the seeds of Sesamum orientale Linn., which contains antioxidant and anticancer activities. The objective of this study was to identify the mechanistic effect of sesamin on human leukemic HL-60, U937 and Molt-4 cell apoptosis.

Methods

The cytotoxicity was performed by 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Reactive oxygen species was measured by employing 2', 7'-dichlorodihydrofluorescein diacetate and flow cytometry. The mitochondrial transmembrane potential was determined by 3,3'-dihexyloxacarbocyanine iodide and flow cytometer. Caspase-3 and -8 activities were detected by using fluorogenic DEVD-AMC and IETD-AMC substrates, respectively. The protein expression of cytochrome c and GADD153, an endoplasmic reticulum (ER) stress protein, was illustrated by immunoblot.

Results

Sesamin was cytotoxic to HL-60 > U937 > Molt-4 > PBMCs and caused the three cell lines to die with the morphology of apoptotic character, i.e., condensed nuclei and apoptotic bodies. It produced reactive oxygen species in all cell lines, with a decrease in mitochondrial transmembrane potential. The caspase-3 activity was increased in sesamin-induced HL-60 cell apoptosis whereas casase-8 activity did not alter. Cytochrome c release was not increased. The expression of GADD153 was increased time dependently, indicating the involvement of ER stress pathway in HL-60 cells.

Conclusions

Sesamin-induced human leukemic cell apoptosis was via oxidative stress, the mitochondrial and ER stress pathways.

Sesamin inhibits bacterial formylpeptide-induced inflammatory responses in a murine air-pouch model and in THP-1 human monocytes

The reaction of human leukocytes to chemoattractants is an important component of the host immune response and also plays a crucial role in the development of inflammation. Sesamin has been shown to inhibit lipid peroxidation and regulate cytokine production. In this study, we examined the effect of sesamin on inflammatory responses elicited by the bacterial chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLF) in vitro and in vivo and explored the mechanisms involved. fMLF is recognized by a human G protein-coupled receptor formyl peptide receptor (FPR) on phagocytic leukocytes. Sesamin at concentrations between 12.5 and 50 micromol/L inhibited fMLF-induced chemotaxis of human monocyte cell line THP-1 differentiated with dibutyryl cyclic AMP (P < 0.01). Similarly, sesamin inhibited FPR-transfected rat basophilic leukemia cell [epitope-tagged human FPR (ETFR) cell] migration toward fMLF (P < 0.01). In fMLF-induced inflammation in a murine air-pouch model, intraperitoneal administration of sesamin (12 mgkg(-1)d(-1) for 2 d) suppressed leukocyte infiltration into the air pouch induced by fMLF [(62.89 +/- 7.93) x 10(4) vs. (19.67 +/- 4.43) x 10(4) cells/air pouch; n = 9; P < 0.001]. Ca(2+) mobilization and mitogen-activated protein kinase extracellular signal-regulated kinase (ERK1/2) activation are involved in fMLF-induced leukocyte migration. Pretreatment of ETFR cells with sesamin inhibited fMLF-induced ERK1/2 phosphorylation in a dose-dependent manner but did not affect fMLF-induced Ca(2+) flux. Electrophoretic mobility shift assay showed that pretreatment of THP-1 cells with sesamin dose dependently inhibited fMLF-induced nuclear factor-kappaB (NF-kappaB) activation. These results suggest that sesamin inhibits leukocyte activation by fMLF through ERK1/2- and NF-kappaB-related signaling pathways and thus is a potential compound for the management of inflammatory diseases.

Are all n-3 polyunsaturated fatty acids created equal?

N-3 Polyunsaturated fatty acids have been shown to have potential beneficial effects for chronic diseases including cancer, insulin resistance and cardiovascular disease. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in particular have been studied extensively, whereas substantive evidence for a biological role for the precursor, alpha-linolenic acid (ALA), is lacking. It is not enough to assume that ALA exerts effects through conversion to EPA and DHA, as the process is highly inefficient in humans. Thus, clarification of ALA's involvement in health and disease is essential, as it is the principle n-3 polyunsaturated fatty acid consumed in the North American diet and intakes of EPA and DHA are typically very low. There is evidence suggesting that ALA, EPA and DHA have specific and potentially independent effects on chronic disease. Therefore, this review will assess our current understanding of the differential effects of ALA, EPA and DHA on cancer, insulin resistance, and cardiovascular disease. Potential mechanisms of action will also be reviewed. Overall, a better understanding of the individual role for ALA, EPA and DHA is needed in order to make appropriate dietary recommendations regarding n-3 polyunsaturated fatty acid consumption.

Plasma lipids and inflammation in active inflammatory bowel diseases

BACKGROUND

Ulcerative colitis (UC) and Crohn's disease (CD) can cause metabolic and inflammatory alterations.

AIM

To evaluate the relationships between inflammatory parameters, plasma lipids and phospholipid fatty acid (FA) composition in patients with active UC and CD.

METHODS

Diet, the Harvey-Bradshaw Activity Index (HBAI), inflammatory parameters, lipoproteins and FA composition were assessed in 60 CD and 34 UC.

RESULTS

No differences in clinical parameters were observed in the two groups. Total cholesterol correlated inversely with the number of bowel movements in both groups and directly with BMI in UC. Arachidonic acid correlated inversely with HBAI in UC and total and HDL cholesterol were inversely related to C-reactive protein (CRP) in CD while HDL correlated with CRP in UC. Docosapentaenoic acid was the only polyunsaturated n-3 FA that was correlated to CRP in both groups. Total cholesterol was independently associated in the multiple regression analysis with the number of bowel movements and systemic inflammation.

CONCLUSIONS

Total and LDL cholesterol were lower in the active UC and CD than in the healthy subjects and were correlated with the systemic inflammatory status. Phospholipid FA composition was correlated to the systemic inflammatory status, but was unrelated to dietary intake and intestinal disease activity.

Olive oil and walnut breakfasts reduce the postprandial inflammatory response in mononuclear cells compared with a butter breakfast in healthy men

BACKGROUND

Inflammation is crucial in all stages of atherosclerosis, and few studies have investigated the effect of dietary fat on markers of inflammation related to this disease during the postprandial period.

OBJECTIVE

To evaluate the chronic effects of dietary fat on the postprandial expression of proinflammatory genes in peripheral blood mononuclear cells (PBMCs) in healthy subjects.

DESIGN

20 healthy men followed three different diets for 4 weeks each, according to a randomized crossover design: Western diet: 15% protein, 47% carbohydrates (CHO), 38% fat (22% saturated fatty acid (SFA)); Mediterranean diet: 15% protein, 47% CHO, 38% fat (24% monounsaturated fatty acid (MUFA)); CHO-rich and n-3 diet: 15% protein, 55% CHO, <30% fat (8% polyunsaturated fatty acid (PUFA)). After 12-h fast, volunteers were given a breakfast with a fat composition similar to that consumed in each of the diets-butter breakfast: 35% SFA; olive oil breakfast: 36% MUFA; walnut breakfast: 16% PUFA, 4% alpha-linolenic acid (LNA).

RESULTS

The butter breakfast induced a higher increase in tumor necrosis factor (TNF)-alpha messenger RNA (mRNA) expression than the olive oil or walnut breakfasts (P=0.014) in PBMCs. Moreover, we found a higher postprandial response in the mRNA of interleukin (IL)-6 with the intake of butter and olive oil breakfasts than with the walnut breakfast (P=0.025) in these cells. However, the effects of the three fatty breakfasts on the plasma concentrations of these proinflammatory parameters showed no significant differences (P=N.S.).

CONCLUSION

Consumption of a butter-enriched meal elicits greater postprandial expression of proinflammatory cytokine mRNA in PBMCs, compared to the olive oil and walnut breakfasts.

Essential fatty acids: biochemistry, physiology and pathology

Essential fatty acids (EFAs), linoleic acid (LA), and alpha-linolenic acid (ALA) are essential for humans, and are freely available in the diet. Hence, EFA deficiency is extremely rare in humans. To derive the full benefits of EFAs, they need to be metabolized to their respective long-chain metabolites, i.e., dihomo-gamma-linolenic acid (DGLA), and arachidonic acid (AA) from LA; and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from ALA. Some of these long-chain metabolites not only form precursors to respective prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs), but also give rise to lipoxins (LXs) and resolvins that have potent anti-inflammatory actions. Furthermore, EFAs and their metabolites may function as endogenous angiotensin-converting enzyme and 3-hdroxy-3-methylglutaryl coenzyme A reductase inhibitors, nitric oxide (NO) enhancers, anti-hypertensives, and anti-atherosclerotic molecules. Recent studies revealed that EFAs react with NO to yield respective nitroalkene derivatives that exert cell-signaling actions via ligation and activation of peroxisome proliferator-activated receptors. The metabolism of EFAs is altered in several diseases such as obesity, hypertension, diabetes mellitus, coronary heart disease, schizophrenia, Alzheimer's disease, atherosclerosis, and cancer. Thus, EFAs and their derivatives have varied biological actions and seem to be involved in several physiological and pathological processes.

Mediation of cognitive function by high fat diet following stress and inflammation

In addition to commonly advertised hazards of obesity contributed by excess dietary fat, evidence of alterations in brain chemistry and structure are well documented. This brief review examines the role of nutrients, minerals and certain lipids, primarily the essential fatty acids (FA), that are beneficial to the maintenance of good health and that may offer therapeutic options by dietary supplementation. The review also considers the damaging effects of stress, especially in pre-existing conditions of obesity and diabetes, as studied in both animals and humans. The main focus of this brief review is to examine the effects of a high fat diet on stress and the immune system with particular emphasis on brain and cognitive function.

Sesamin inhibits lipopolysaccharide-induced cytokine production by suppression of p38 mitogen-activated protein kinase and nuclear factor-kappaB

Sesame seed oil increases the survival after cecal ligation and puncture in mice and the increased IL-10 levels with non-lethal lipopolysaccharides (LPS) challenge. We showed that sesamin and sesamolin, major lignans of sesame oil, regulated LPS-induced nitric oxide production in the murine microglia and BV-2 cell line. In this study, we studied the effect of sesamin on cytokine production by LPS stimulation. The result showed that sesamin significantly inhibited LPS-stimulated IL-6 mRNA and protein, and to a lesser degree TNF-alpha, in BV-2 microglia. Sesamin and sesamolin also reduced LPS-activated p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB activations. Furthermore, SB203580, a specific inhibitor of p38 MAP kinase, specifically inhibited LPS-induced IL-6 production. These results suggest that sesamin inhibited LPS-induced IL-6 production by suppression of p38 MAPK signal pathway and NF-kappaB activation.

The effect of diet enriched with α-linolenic acid on soluble cellular adhesion molecules in dyslipidaemic patients

BACKGROUND

Leukocyte adhesion and transendothelial migration, the critical pathogenic components in the development of atherosclerotic lesions, are largely mediated by cellular adhesion molecules (CAMs). We examined whether dietary supplementation with alpha-linolenic acid (ALA, 18:3n-3) affects the levels of soluble forms of CAMs in dyslipidaemic patients.

METHODS

We recruited 90 male dyslipidaemic patients (mean age=51+/-8 years) following a typical Greek diet. They were randomly assigned either to 15 ml of linseed oil (rich in ALA) per day (n=60) or to 15 ml of safflower oil (rich in linoleic acid [LA, 18:2n-6]) per day (n=30). The ratio of n-6:n-3 in linseed oil supplemented group was 1.3:1 and in safflower oil supplemented group 13.2:1. Dietary intervention lasted for 12 weeks. Blood lipids, soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble E-selectin (sE-selectin) were measured.

RESULTS

Dietary supplementation with ALA significantly decreased sVCAM-1 levels (median decrease 18.7% [577.5 ng/ml versus 487 ng/ml, P=0.0001]). In the LA supplemented group, sVCAM-1 was also significantly decreased but to a lesser extent (median decrease 10.6% [550.5 ng/ml versus 496 ng/ml, P=0.0001]). After controlling for smoking habits, no significant difference was observed in the reduction of sVCAM-1 levels between the two treatment arms (P=0.205). The decrease of sVCAM-1 was independent of lipid changes in both groups.

CONCLUSIONS

Dietary supplementation with ALA for 12 weeks significantly decreases sVCAM-1 levels in dyslipidaemic patients. This effect presents a potential mechanism for the beneficial effect of plant n-3 polyunsaturated fatty acids in the prevention of coronary artery disease. In addition, dietary supplementation with LA significantly decreases sVCAM-1 levels, an effect which requires further investigation.

Effect of sesame antioxidants on LPS-induced NO production by BV2 microglial cells

Sesame antioxidants have been shown to inhibit lipid peroxidation and regulate cytokine production. In this study, we focused on the effect of sesamin and sesamolin, on nitric oxide (NO) induction by lipopolysaccharides (LPS) in the murine microglial cell line BV-2 and rat primary microglia. The results showed that sesamin and sesamolin significantly inhibited NO production, iNOS mRNA and protein expression in LPS-stimulated BV-2 cells. Sesamin or sesamolin significantly reduced LPS-activated p38 MAPK of BV-2 cells. Furthermore, SB203580, a specific inhibitor of p38 MAP kinase, dose-dependently inhibited NO production in LPS-stimulated BV-2 cells. Taken together, the inhibition of NO production might be due to the reduction of LPS-induced p38 MAPK signal pathway by sesamin and sesamolin.

Dietary alpha-linolenic acid decreases C-reactive protein, serum amyloid A and interleukin-6 in dyslipidaemic patients

BACKGROUND

Inflammation plays an important role in the pathogenesis of coronary artery disease. We examined whether dietary supplementation with alpha-linolenic acid (ALA, 18:3n-3) affects the levels of inflammatory markers in dyslipidaemic patients.

METHODS

We recruited 76 male dyslipidaemic patients (mean age=51+/-8 years) following a typical Greek diet. They were randomly assigned either to 15 ml of linseed oil (rich in ALA) per day (n=50) or to 15 ml of safflower oil (rich in linoleic acid (LA, 18:2n-6)) per day (n=26). The ratio of n-6:n-3 in linseed oil supplemented group was 1.3:1 and in safflower oil supplemented group 13.2:1. Dietary intervention lasted for 3 months. Blood lipids and C-reactive protein (CRP), serum amyloid A (SAA), and interleukin-6 (IL-6) levels were determined prior and after intervention. CRP and SAA were measured by nephelometry and IL-6 by immunoassay.

RESULTS

Dietary supplementation with ALA decreased significantly CRP, SAA and IL-6 levels. The median decrease of CRP was 38% (1.24 vs. 0.93 mg/l, P=0.0008), of SAA 23.1% (3.24 vs. 2.39 mg/l, P=0.0001) and of IL-6 10.5% (2.18 vs. 1.7 pg/ml, P=0.01). The decrease of inflammatory markers was independent of lipid changes. Dietary supplementation with LA did not affect significantly CRP, SAA and IL-6 concentrations but decreased cholesterol levels.

CONCLUSIONS

Dietary supplementation with ALA for 3 months decreases significantly CRP, SAA and IL-6 levels in dyslipidaemic patients. This anti-inflammatory effect may provide a possible additional mechanism for the beneficial effect of plant n-3 polyunsaturated fatty acids in primary and secondary prevention of coronary artery disease.

Immunomodulation by perioperative administration of n-3 fatty acids

It has been increasingly reported that administration of n-3 fatty acids is beneficial in patients with inflammatory processes. This effect is most likely caused by different biological characteristics, including an immunomodulating effect of the products derived from n-3 fatty acids through eicosanoid metabolism. The aim of this study was to investigate the effect of perioperative administration of n-3 fatty acids on inflammatory and immune responses as well as on the postoperative course of patients with extended surgical interventions of the abdomen. In particular, the effect of n-3 fatty acids on interleukin-6 release and on granulocyte/monocyte function (HLA-DR expression) was studied. There was a downregulation of the inflammatory response, and, simultaneously, a smaller postoperative immune suppression in the n-3 fatty acid group. In addition, we observed shorter postoperative periods in the intensive care unit and on the regular medical wards as well as lower rates of severe infections. The results suggest that perioperative administration of n-3 fatty acids may have a favourable effect on outcome in patients with severe surgical interventions by lowering the magnitude of inflammatory response and by modulating the immune response.

Increased survival after cecal ligation and puncture in mice consuming diets enriched with sesame seed oil

OBJECTIVES

Lignans that present in the nonfat portion of sesame seed oil (SSO) can inhibit delta-5 desaturase activity, resulting in an increase in the accumulation of dihomo-gamma-linolenic acid and, subsequently, decrease the production of proinflammatory dienoic eicosanoids with a concomitant increase in the secretion of less inflammatory monoenoic eicosanoids.

DESIGN

Female Balb/c mice were fed diets supplemented with 5wt% SSO or a physical mixture of oils (control) whose fatty acid composition resembled that of SSO for 3 wks.

MEASUREMENTS AND MAIN RESULTS

During a 4-day observation period after cecal ligation and puncture, only 20% of the controls and as many as 65% in the SSO group survived. Furthermore, the levels of cytokines and dienoic eicosanoids produced in response to an intraperitoneal injection of a nonlethal dose (50 microg/mouse) of endotoxin were measured in both groups. The interleukin (IL)-10 levels were markedly higher in mice fed SSO diets compared with the controls. However, the plasma concentrations of prostaglandin E1 + 2, tumor necrosis factor-alpha, IL-6, and IL-12 did not differ significantly between the two groups of mice.

CONCLUSIONS

Because the fatty acid composition is almost similar between the two diets, sesamin, sesamol and other lignans in SSO appear to be responsible for an increase in survival after cecal ligation and puncture and also for an increase in the IL-10 levels in response to a nonlethal dose of endotoxin in mice.

Effects of sesamin-supplemented dietary fat emulsions on the ex vivo production of lipopolysaccharide-induced prostanoids and tumor necrosis factor alpha in rats

BACKGROUND

Sesamin, a nonfat constituent of sesame oil, inhibits Delta(5)-desaturase activity, resulting in accumulation of dihomo-gamma-linolenic acid (DGLA), which displaces arachidonic acid (AA) and consequently decreases the formation of proinflammatory 2-series prostaglandins.

OBJECTIVE

We sought to determine whether dietary supplementation with sesamin augments the antiinflammatory effects of dietary linseed oil in rats.

DESIGN

We investigated the effects of continuous tube feedings of emulsions containing safflower oil or linseed oil with sesamin (SO+ and LO+) or without sesamin (SO and LO) on liver fatty acid composition and on endotoxin-induced production of prostaglandin E(2), 6-keto-prostaglandin F(1alpha), and tumor necrosis factor alpha (TNF-alpha) by whole blood from rats (n = 6 per diet group).

RESULTS

We found a significant accumulation of DGLA only in the liver phospholipids of animals fed SO+ and LO+ (1.8 +/- 0.2 and 1.4 +/- 0.3 mol%, respectively), which suggests that sesamin inhibited Delta(5)-desaturation of n-6 fatty acids. These changes were associated with significant reductions in plasma prostaglandin E(2) concentrations in animals fed SO+ compared with those fed SO (P: < 0. 05). Despite a significant reduction in tissue AA content in the LO group, the prostaglandin E(2) concentrations did not differ significantly from those of the SO group. Plasma concentrations of TNF-alpha were significantly lower (P: < 0.05) in the animals fed LO+ than in those fed SO (199 +/- 48 and 488 +/- 121 ng/L, respectively).

CONCLUSION

These data indicate that in rats, tube feedings of diets containing sesamin exerted antiinflammatory effects that were augmented by concurrent consumption of linseed oil.

Essential fatty acids and the brain: possible health implications

Linoleic and alpha-linolenic acid are essential for normal cellular function, and act as precursors for the synthesis of longer chained polyunsaturated fatty acids (PUFAs) such as arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), which have been shown to partake in numerous cellular functions affecting membrane fluidity, membrane enzyme activities and eicosanoid synthesis. The brain is particularly rich in PUFAs such as DHA, and changes in tissue membrane composition of these PUFAs reflect that of the dietary source. The decline in structural and functional integrity of this tissue appears to correlate with loss in membrane DHA concentrations. Arachidonic acid, also predominant in this tissue, is a major precursor for the synthesis of eicosanoids, that serve as intracellular or extracellular signals. With aging comes a likely increase in reactive oxygen species and hence a concomitant decline in membrane PUFA concentrations, and with it, cognitive impairment. Neurodegenerative disorders such as Parkinson's and Alzheimer's disease also appear to exhibit membrane loss of PUFAs. Thus it may be that an optimal diet with a balance of n-6 and n-3 fatty acids may help to delay their onset or reduce the insult to brain functions which these diseases elicit.

In humans, serum polyunsaturated fatty acid levels predict the response of proinflammatory cytokines to psychologic stress

BACKGROUND

Psychologic stress in humans induces the production of proinflammatory cytokines, such as interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 (IL-6), and that of the negative immunoregulatory cytokine, IL-10. An imbalance of omega6 to omega3 polyunsaturated fatty acids (PUFAs) in the peripheral blood causes an overproduction of proinflammatory cytokines. The omega3 PUFAs reduce the production of proinflammatory cytokines.

METHODS

This study examines whether an imbalance in omega6 to omega3 PUFAs in human blood predicts a greater production of proinflammatory cytokines in response to psychologic stress. Twenty-seven university students had serum sampled a few weeks before and after as well as 1 day before a difficult oral examination. We determined the omega6 and omega3 fractions in serum phospholipids as well as the ex vivo production of IFN-gamma, TNF-alpha, IL-6, IL-10, and IL-5 by diluted whole blood stimulated with polyclonal activators.

RESULTS

Academic examination stress significantly increased the ex vivo, stimulated production of IFN-gamma, TNF-alpha and IL-10, and the IFN-gamma/IL-5 production ratio. Subjects with lower serum omega3 PUFA levels or with a higher omega6/omega3 ratio had significantly greater stress-induced TNF-alpha and IFN-gamma responses than subjects with higher serum omega3 PUFAs and a lower omega6/omega3 ratio, respectively. Subjects with lower serum omega3 PUFA levels or with a higher omega6/omega3 ratio had a significantly higher stress-induced increase in the IFN-gamma/IL-5 ratio than the remaining subjects.

CONCLUSIONS

Psychologic stress induces a Th-1-like or proinflammatory response in some subjects. An imbalance in the omega6 to omega3 PUFA ratio appears to predispose humans toward an exaggerated Th-1-like response and an increased production of monocytic cytokines, such as TNF-alpha, in response to psychologic stress. The results suggest that increased omega3 PUFA levels may attenuate the proinflammatory response to psychologic stress.

Decreased production of interleukin-6 and prostaglandin E2 associated with inhibition of delta-5 desaturation of omega6 fatty acids in mice fed safflower oil diets supplemented with sesamol

The differences in the immune responses in mice fed sesame oil diets and those fed sesamin may be attributed to the presence of other lignans in the non-fat portion of the oil. The fatty acid composition (mean +/- SD mol. %) of liver membrane phospholipids and the levels of endotoxin-induced prostaglandin (PG) E2, interleukin (IL)-6, IL-10, IL-12 and tumor necrosis factor (TNF)-alpha were determined in mice fed diets supplemented with 5% safflower oil (SO) in the absence or presence of 1% sesamol. The levels of dihomo-gamma-linolenic acid (20:3omega6) were markedly higher (P<0.025) in the livers from mice fed sesamol supplemented SO diets (1.6 +/- 0.1) compared to the controls (1.4 +/- 0.1). These data suggest that sesamol or its metabolite could inhibit the in vivo delta-5 desaturation of omega6 fatty acids. Further, in animals fed sesamol supplemented SO diets, the levels of PGE2 (228 +/- 41 pg/ml) were markedly lower (P<0.01) compared to those fed SO diet alone (1355 +/- 188 pg/ml). Concomitantly, the concentrations of IL-6 were also lower (P<0.01) in mice fed sesamol diet (63 +/- 11 ng/ml) compared to the controls (143 +/- 22 ng/ml). A marked reduction in the levels of PGE2 in animals fed sesamol diets suggests that sesamol or its metabolite could inhibit the activity of cyclooxygenase enzyme.