Polyunsaturated Fatty Acid-rich Diet Research Articles

Comprehensive Lipidomics Analysis Reveals the Effects of Different Omega-3 Polyunsaturated Fatty Acid-Rich Diets on Egg Yolk Lipids.

Dietary supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFAs) for laying hens enriches eggs with these essential fatty acids. However, the enrichment patterns and changes to intact lipids in egg yolk have not been sufficiently revealed. Herein, egg yolk lipids from hens fed with diets supplemented with flaxseed, Schizochytrium sp. residue, or their mixture were comprehensively analyzed using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A total of 335 individual lipid species covering 23 (sub)classes were identified and quantified. Distinct n-3 PUFA-lipid profiles were revealed among different groups. Dietary α-linolenic acid (ALA) was mainly deposited in the TAG fraction, whereas synthesized or preformed docosahexaenoic acid (DHA) predominantly existed in the glycerophospholipid form. Furthermore, different lipid species were identified and related lipid pathways after dietary supplementation were analyzed. Collectively, these findings provide us with new knowledge for production, nutritional evaluation, authentication, and application of n-3 PUFA-enriched eggs.

Effect of Olive Leaves or Marigold Petal Extract on Oxidative Stress, Gut Fermentative Activity, and Mucosa Morphology in Broiler Chickens Fed a Diet Rich in n-3 Polyunsaturated Fats.

An experiment in broilers was conducted to investigate the effect of olive (Olea europea) leaves and marigold (Calendula officinalis) petal extract supplementation on oxidative stress, characteristics of intestinal contents, and on the morphology of the small intestine. Oxidative stress was induced by a n-3 polyunsaturated fatty acids rich diet. 1-day-old male broiler chickens, Ross 308, were housed in a deep litter system. After the first 21 days, animals were randomly divided into three groups of 16 animals in two replicates and fed, until slaughter on day 39, a diet that contained 7% linseed oil. Control diet (Cont) remained unsupplemented, while both experimental diets were supplemented with olive leaves (OliveEx) or marigold petal (MarigEx) extracts. Oxidative stress was evaluated in blood and liver by measuring markers of lipid peroxidation (malondialdehyde (MDA), isoprostanes), rate of DNA damage in lymphocytes and in blood (comet assay, 8-hydroxy-2′deoxyguanosine (8-OHdG)), and activity of antioxidant and liver enzymes in blood. In different parts of the intestine, levels of short chain fatty acids (SCFA), and viscosity of intestinal contents were measured, and the health of the gastrointestinal tract was assessed using histological measurements. OliveEx significantly (p<0.05) decreased the MDA and 8-OHdG concentration in plasma, and the level of ethanoic acid in small intestinal contents and total SCFA in caecum, indicating improved oxidative status and increased microbial activity in the intestine. MarigEx significantly (p<0.05) decreased the rate of lymphocyte DNA damage and the crypt depth in duodenum, indicating potentially beneficial effects on the immune system and the health of the small intestine. In conclusion, dietary OliveEx and MarigEx supplementation improved some markers of oxidative stress and intestinal health. However, positive effects could be more pronounced in more unfavorable environmental conditions or in cases of diseases, but further studies are needed.

Nematodes as Important Source for Omega-3 Long-Chain Fatty Acids in the Soil Food Web and the Impact in Nutrition for Higher Trophic Levels

PUFA (polyunsaturated fatty acids) content of food sources, in particular 3 long-chain PUFA with three or more double bonds, are considered essential for growth, reproduction, and neural development of higher animals. Surprisingly, and in contrast to aquatic ecosystems, 3 long-chain PUFA seem not widely available in terrestrial food webs. Far-reaching ideas indeed proclaim aquatic ecosystems as the principal source of these long-chain PUFA in the whole biosphere, including inhabitants of terrestrial ecosystems. Interestingly, de novo synthesis of 3 long-chain PUFA, which requires the presence of Δ12 (fat-2) and 3 (fat-1) desaturases absent in vertebrates, has been observed in nematodes, such as Caenorhabditis elegans. This raises the question if nematodes or other soil invertebrates present an important trophic link offering substantial supply in these valuable nutritional compounds in terrestrial food webs. This work followed the dietary routing of fatty acids of different C. elegans strains, including mutants defective in the PUFA biosynthesis, to two omnivorous Collembola species, Folsomia candida and Protaphorura fimata. The laboratory approach comprised microcosms offering binary links under various feeding conditions and analyzed growth, fecundity and dietary preference of consumers. Collembola did not prefer individual C. elegans strains as food source but they clearly reflected the PUFA-richness or -poorness of their nematode prey in their neutral lipid fraction. Moreover, Collembola did benefit from 3 long-chain PUFA rich diet, as shown by significant weight gain and increased number of laid eggs. Interestingly, the comparatively high PUFA-content of Collembola’s phospholipid fraction remained unchanged, even in response to almost PUFA-depleted nematode prey, suggesting that these Collembola species also possess the metabolic capability to de novo synthesize PUFA, including 3 long-chain forms. These findings broaden the basis of long-chain PUFA sources in terrestrial food webs and question the impact of aquatic ecosystems as principal source.

N-3 PUFA diet enrichment prevents amyloid beta-induced depressive-like phenotype

Among neuropsychiatric diseases, depression is one of the most prevalent. Many pathologies have been indicated as comorbid with depression and in particular, neurodegenerative disorders such as Alzheimer’s diseases (AD). In this regard, several evidences endorse a strong relationship between depression and AD, so much that this mental illness has been proposed either as a risk factor for AD or as a prodromic AD phase. Furthermore, amyloid beta (Aβ) peptide, the main constituent of amyloid plaques commonly considered the principal hallmark of AD brains, has been shown to be increased, in its soluble form, in depressed patients. Accordingly, we have previously found that Aβ, intracerebroventricularly (i.c.v.) injected, is able to evoke a depressive-like profile in rats accompanied by low cortical serotonin and reduced neurotrophin content. Taking into account the great increase in AD and depression prevalence, many environmental factors have been under study, particularly dietary factors, and the role of polyunsaturated fatty acids (PUFA) is becoming central in this field of research. Thus, aim of the present study was to evaluate the neurobehavioral effects of lifelong exposure to either n-3 PUFA rich or n-3 PUFA poor diet after Aβ central administration. Results showed that n-3 PUFA enriched diet prevented the Aβ- induced depressive-like behaviors, as reveled by the reduction in the immobility time in the FST test. Furthermore, n-3 PUFA rich diet exposure reverted also serotonin and neurotrophin level reduction in prefrontal cortex of Aβ treated rats.Taken together, our data support the concept that supplementation of diet with n-3 PUFA represents a valid approach to reduce the risk of developing depressive symptoms, as well as reducing the risk of Aβ-related pathologies, such as AD.

Coenzyme Q Protects Against Age-Related Alveolar Bone Loss Associated to n-6 Polyunsaturated Fatty Acid Rich-Diets by Modulating Mitochondrial Mechanisms.

An age-dependent model of the periodontium was reproduced to evaluate the effect of life-long feeding on a low coenzyme Q10 dosage in n-6, n-3 polyunsaturated fatty acid or monounsaturated fatty acid-based diets on periodontal tissues of young and old rats. Results shown that exacerbated age-related alveolar bone loss previously associated to n-6 polyunsaturated fatty acid diet was attenuated by coenzyme Q10 Gene expression analysis suggests that involved mechanisms might be related to a restored capacity of mitochondria to adapt to aging in gingival cells from rats fed on n-6 polyunsaturated fatty acid. In particular, this could be due to an age-related increase of the rate of mitochondrial biogenesis and a better oxidative and respiratory balance in these animals. From the nutritional and clinical point of view, it is noteworthy that supplementation with coenzyme Q10 could counteract the negative effects of n-6 polyunsaturated fatty acid on alveolar bone loss (a major feature of periodontitis) associated to age.

Maternal exposure to fish oil primes offspring to harbor intestinal pathobionts associated with altered immune cell balance

Our previous studies revealed that offspring from rat dams fed fish oil (at 8% and 18% energy), developed impaired intestinal barriers sensitizing the colon to exacerbated injury later in life. To discern the mechanism, we hypothesized that in utero exposure to fish oil, rich in n-3 polyunsaturated fatty acid (PUFA), caused abnormal intestinal reparative responses to mucosal injury through differences in intestinal microbiota and the presence of naïve immune cells. To identify such mechanisms, gut microbes and naïve immune cells were compared between rat pups born to dams fed either n-6 PUFA, n-3 PUFA or breeder chow. Maternal exposure to either of the PUFA rich diets altered the development of the intestinal microbiota with an overall reduction in microbial density. Using qPCR, we found that each type of PUFA differentially altered the major gut phyla; fish oil increased Bacteroidetes and safflower oil increased Firmicutes. Both PUFA diets reduced microbes known to dominate the infant gut like Enterobacteriaceae and Bifidobacteria spp. when compared to the chow group. Uniquely, maternal fish oil diets resulted in offspring showing blooms of opportunistic pathogens like Bilophila wadsworthia, Enterococcus faecium and Bacteroides fragilis in their gut microbiota. As well, fish oil groups showed a reduction in colonic CD8+ T cells, CD4+ Foxp3+ T cells and arginase+ M2 macrophages. In conclusion, fish oil supplementation in pharmacological excess, at 18% by energy as shown in this study, provides an example where excess dosing in utero can prime offspring to harbor intestinal pathobionts and alter immune cell homeostasis.

Ischemic Preconditioning-Like Effect of Polyunsaturated Fatty Acid-Rich Diet on Hepatic Ischemia/Reperfusion Injury

AimThe aim of this study was to investigate a possible preconditioning effect of oral diet enriched with polyunsaturated fatty acids (PUFAs) on liver ischemia/reperfusion (I/R) injuries. MethodsWistar male rats were fed a standard diet or polyunsaturated fatty acid-rich diet (PRD) enriched with (GII) or without (GIII) ω-3 PUFA. Rats were submitted to partial liver ischemia during 1 h and evaluated in pre- and post-I/R conditions. In pre-I/R condition, livers were collected for determination of fatty acid composition, liver mitochondrial function, malondialdehyde (MDA) content, and histological analysis. Four hours after liver reperfusion serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), serum levels of tumor necrosis factor-alpha, interleukin-6, interleukin-10, and prostaglandin-E2, liver mitochondrial function, MDA content, and histology were evaluated. ResultsIn the pre-I/R condition, GII and GIII groups had an increase on PUFA content and exhibited slight increased macrosteatosis and microsteatosis in the liver. After 4 h of reperfusion, PRD-fed rats showed a marked decrease on steatosis, diminished necrosis, an increase in MDA formation, and mitochondrial uncoupling. We also observed a marked decrease in plasma levels of cytokines and ALT and AST activities in post-I/R condition in PRD groups. ConclusionIn this experimental model in the rat, PRD has a preconditioning effect protecting the liver from I/R injury and should be object of future clinical studies.

Effects of alpha-linolenic acid vs. docosahexaenoic acid supply on the distribution of fatty acids among the rat cardiac subcellular membranes after a short- or long-term dietary exposure.

BackgroundPrevious work showed that the functional cardiac effect of dietary alpha-linolenic acid (ALA) in rats requires a long feeding period (6 months), although a docosahexaenoic (DHA) acid-supply affects cardiac adrenergic response after 2 months. However, the total cardiac membrane n-3 polyunsaturated fatty acid (PUFA) composition remained unchanged after 2 months. This delay could be due to a specific reorganization of the different subcellular membrane PUFA profiles. This study was designed to investigate the evolution between 2 and 6 months of diet duration of the fatty acid profile in sarcolemmal (SL), mitochondrial (MI), nuclear (NU) and sarcoplasmic reticulum (SR) membrane fractions.MethodsMale Wistar rats were randomly assigned to 3 dietary groups (n = 10/diet/period), either n-3 PUFA-free diet (CTL), or ALA or DHA-rich diets. After 2 or 6 months, the subcellular cardiac membrane fractions were separated by differential centrifugations and sucrose gradients. Each membrane profile was analysed by gas chromatography (GC) after lipid extraction.ResultsAs expected the n-3 PUFA-rich diets incorporated n-3 PUFA instead of n-6 PUFA in all the subcellular fractions, which also exhibited individual specificities. The diet duration increased SFA and decreased PUFA in SL, whereas NU remained constant. The SR and MI enriched in n-3 PUFA exhibited a decreased DHA level with ageing in the DHA and CTL groups. Conversely, the n-3 PUFA level remained unchanged in the ALA group, due to a significant increase in docosapentaenoic acid (DPA). N-3 PUFA rich diets lead to a better PUFA profile in all the fractions and significantly prevent the profile modifications induced by ageing.ConclusionWith the ALA diet the n-3 PUFA content, particularly in SR and SL kept increasing between 2 and 6 months, which may partly account for the delay to achieve the modification of adrenergic response.

Effects of Rice Bran Oil Enriched with n‐3 PUFA on Liver and Serum Lipids in Rats

Lipase-catalyzed interesterification was used to prepare different structured lipids (SL) from rice bran oil (RBO) by replacing some of the fatty acids with alpha-linolenic acid (ALA) from linseed oil (LSO) and n-3 long chain polyunsaturated fatty acids (PUFA) from cod liver oil (CLO). In one SL, the ALA content was 20% whereas in another the long chain n-3 PUFA content was 10%. Most of the n-3 PUFA were incorporated into the sn-1 and sn-3 positions of triacylglycerol. The influence of SL with RBO rich in ALA and EPA + DHA was studied on various lipid parameters in experimental animals. Rats fed RBO showed a decrease in total serum cholesterol by 10% when compared to groundnut oil (GNO). Similarly structured lipids with CLO and LSO significantly decreased total serum cholesterol by 19 and 22% respectively compared to rice bran oil. The serum TAGs level of rats fed SLs and blended oils were also significantly decreased by 14 and 17% respectively compared to RBO. Feeding of an n-3 PUFA rich diet resulted in the accumulation of long chain n-3 PUFA in various tissues and a reduction in the long chain n-6 PUFA. These studies indicate that the incorporation of ALA and EPA + DHA into RBO can offer health benefits.

An enhanced apoptosis and a reduced angiogenesis are associated with the inhibition of lung colonisation in animals fed ann-3 polyunsaturated fatty acid-rich diet injected with a highly metastatic murine melanoma line

Both epidemiological and experimental studies indicate that dietary n-3 PUFA inhibit carcinogenesis and tumour growth. Metastatic diffusion has also been found to be affected in animals fed diets containing purified n-3 PUFA or fish oil. In the present study, we investigated whether the metastatic diffusion of a highly metastatic variant (F10-SR cells) isolated from the B16 melanoma F10 line was affected by feeding host animals a diet containing 5 % fish oil. In these animals, compared with those fed a diet containing 5 % maize oil, there was a reduced number of metastatic pulmonary colonies. The immunohistochemical analysis of appropriate markers revealed that the antimetastatic effect of dietary n-3 PUFA was not related to a reduction of proliferation, but rather to an enhanced apoptotic activity. The reduction of von Willebrand factor immunoreactivity found in pulmonary colonies of F10-SR cells grown in fish oil-fed animals indicates that a decrease of angiogenesis contributes to the antimetastatic effect of dietary n-3 PUFA. This conclusion stands in spite of the higher expression of vascular endothelial growth factor observed in pulmonary colonies grown in fish oil-fed animals.

The antioxidative effect of plant extracts rich in polyphenols differs between liver and muscle tissues in rats fed n-3 PUFA rich diets

The susceptibility of lipids to lipoperoxidation in tissues can be enhanced by increasing the content in polyunsaturated fatty acids (PUFA) in lipids or by inducing an overproduction of reactive oxygen species (ROS) as it is the case under oxidative stress conditions. In contrast, the intake of dietary antioxidants limits lipoperoxidation by preventing the attack of PUFA by ROS. Domestic animals are particularly exposed to lipoperoxidation since the use of PUFA rich diets has been developed to improve the nutritional value of animal's products. Vitamin E is the antioxidant most commonly used in animal nutrition but it presents some drawbacks which have lead to research new natural and powerful antioxidants. In this context, it was assumed that plant extracts rich in polyphenols (PERP) could be good candidates and the aim of this experiment was to investigate the bioefficiency of PERP to prevent lipoperoxidation in animals fed a n-3 PUFA rich diet. Four PERP (rosemary, RO; grape, GP; citrus, CI and marigold, MA) were selected and orally administrated (0.5 g/kg diet) to rats given a diet enriched with 15% of linseed oil (rich in 18:3 n-3). The present experiment was specifically designed to investigate the ability of the PERP to limit lipoperoxidation in different tissues (liver, Longissimus thoracis muscle and heart) and therefore to support results already reported in plasma. In liver, malondialdehyde (MDA) production was decreased by 30% in PERP supplemented rats, especially with RO and CI (−34%, P<0.05). This effect was associated with an increase in vitamin E for RO and GP (+24 and +11% respectively, P<0.05) and an enhancement of catalase activity for GP and MA (+13% and +11%, P<0.05). In muscle tissues, lipoperoxidation intensity was not significantly modified by PERP and it was assumed that a longer supplementation period would have been necessary to improve the oxidative stability of extra-hepatic tissues. It was concluded that the bioefficiency of the 4 PERP depended on the type of tissue and their protective effects were probably achieved by different mechanisms. Further work is now necessary to confirm these biological properties in domestic animals of agronomical interest.

Dietary Intake of n-6 Fatty Acids Modulates Effect of Apolipoprotein A5 Gene on Plasma Fasting Triglycerides, Remnant Lipoprotein Concentrations, and Lipoprotein Particle Size

Apolipoprotein A5 gene (APOA5) variation is associated with plasma triglycerides (TGs). However, little is known about whether dietary fat modulates this association. We investigated the interaction between APOA5 gene variation and dietary fat in determining plasma fasting TGs, remnant-like particle (RLP) concentrations, and lipoprotein particle size in 1001 men and 1147 women who were Framingham Heart Study participants. Polymorphisms -1131T>C and 56C>G, representing 2 independent haplotypes, were analyzed. Significant gene-diet interactions between the -1131T>C polymorphism and polyunsaturated fatty acid (PUFA) intake were found (P<0.001) in determining fasting TGs, RLP concentrations, and particle size, but these interactions were not found for the 56C>G polymorphism. The -1131C allele was associated with higher fasting TGs and RLP concentrations (P<0.01) in only the subjects consuming a high-PUFA diet (>6% of total energy). No heterogeneity by sex was found. These interactions showed a dose-response effect when PUFA intake was considered as a continuous variable (P<0.01). Similar interactions were found for the sizes of VLDL and LDL particles. Only in carriers of the -1131C allele did the size of these particles increase (VLDL) or decrease (LDL) as PUFA intake increased (P<0.01). We further analyzed the effects of n-6 and n-3 fatty acids and found that the PUFA-APOA5 interactions were specific for dietary n-6 fatty acids. Higher n-6 (but not n-3) PUFA intake increased fasting TGs, RLP concentrations, and VLDL size and decreased LDL size in APOA5 -1131C carriers, suggesting that n-6 PUFA-rich diets are related to a more atherogenic lipid profile in these subjects.

Prevention of Colon Cancer by Low Doses of Celecoxib, a Cyclooxygenase Inhibitor, Administered in Diet Rich in ω-3 Polyunsaturated Fatty Acids

Epidemiologic and animal studies suggest that a high-fat diet containing mixed lipids promotes colorectal cancer, whereas fish oil lacks promoting effect. Although cyclooxygenase-2 (COX-2) inhibitors are effective chemopreventive agents against colon carcinogenesis, administration of high doses of these agents over time may induce side effects. Here, we compared the efficacy of moderately high and low doses of celecoxib administered in diets high in mixed lipids (HFML) or fish oil (HFFO) against azoxymethane-induced colon carcinogenesis in male F344 rats. One day after the last azoxymethane treatment (15 mg/kg body weight once weekly for 2 weeks), groups of rats were fed the HFML and HFFO diets containing 0, 250, 500, and 1,000 ppm celecoxib. Rats were killed 26 weeks later and colon tumors were subjected to histopathologic examination and analyzed for total COX and COX-2 synthetic activities and COX-2 expression. Rats fed the HFFO diet showed significantly lower colon tumor incidence and multiplicity compared with rats fed the HFML diet. Celecoxib at 250, 500, and 1,000 ppm in either diet significantly suppressed colon carcinogenesis. Inhibition of colon adenocarcinomas were more pronounced in animals given 250 ppm celecoxib in HFFO diet compared with 250 ppm celecoxib given in HFML diet, suggesting some synergism between omega-3 polyunsaturated fatty acids (PUFA) and celecoxib. Inhibition of colon tumors by celecoxib was associated with lower levels of COX-2 activity and expression in colon tumors. These studies support the use of low doses of celecoxib in omega-3 PUFA-rich diet as a promising approach for clinical trials.

Polyunsaturated fatty acids partially reproduce the role of melanocytes in the epidermal melanin unit

The incidence rate of melanoma is higher in fair-skinned than in dark-skinned individuals. In negroid skin there is more eumelanin which is present in all skin layers and fewer polyunsaturated fatty acids (PUFA) than in caucasoid skin. The western diet, which is rich in omega-6 polyunsaturated fatty acids, is associated with more proneness to cancer including cutaneous melanoma. To study the respective influence of omega-6 PUFA and low phototype melanocytes on redox status -basal and following UV irradiation-, we used epidermal reconstructs. The addition of polyunsaturated fatty acids as well as the presence of low phototype melanocytes affected basal status similarly except for catalase activity, which decreased significantly in polyunsaturated fatty acid-supplemented reconstructs. Following UV, polyunsaturated fatty acids and low phototype melanocytes increased lipid and protein oxidative damage without affecting direct DNA damage. However, polyunsaturated fatty acids increased epidermal apoptosis whereas low phototype melanocytes decreased it. Since our data suggest that an omega-6 PUFA rich-diet may increase oxidative damage in melanocytes without inducing apoptosis, the long-term net outcome could be cumulated mutations and an increased risk of skin cancer, especially melanoma.

Participation of corticosteroids and effects of indomethacin on the acute inflammatory response of rats fed n-6 or n-3 polyunsaturated fatty acid-rich diets.

We have previously shown that both n-3 (fish oil) and n-6 (soybean oil) PUFA-rich diets reduce carrageenan-induced paw edema in rats. The present study evaluated the role of corticosteroids, and the effect of indomethacin on this response. Basal (pre-carrageenan) levels of corticosterone were elevated in both lipid diets compared to the chow diet. During inflammation, corticosterone levels increased to a similar extent in the chow and lipid diets. With 2.0 mg/kg indomethacin, edema was reduced in the chow diet and the n-3 diet, while it was not changed in the n-6 diet. In contrast, the 16.6 mg/kg dose of indomethacin induced a mild increase in edema in the chow diet but a pronounced edema increase in the lipid diets. The increase in corticosterone levels induced by carrageenan was either reduced (chow) or completely abolished (lipids) by the treatment with the higher dose of indomethacin, compared to both the control (untreated) group, and the lower dose of indomethacin. These data indicate that both acute inflammation and the response to an antiinflammatory drug were attenuated by n-3 or n-6 PUFA-rich diets. They also showed that indomethacin can have anti- or proinflammatory properties reflecting the extent of the corticosterone inhibition by indomethacin.

Tissue Specific Interactions of Exercise, Dietary Fatty Acids, and Vitamin E in Lipid Peroxidation

Both physical exercise and ingestion of polyunsaturated fatty acids that play an essential role in free radical-mediated damages cause lipid peroxidation. The intake of specific fatty acids can modulate the membrane susceptibility to lipid peroxidation. Data confirmed that liver, skeletal muscle, and heart have different capabilities to adapt their membrane composition to dietary fatty acids, the heart being the most resistant to changes. Such specificity affects membrane hydroperoxide levels that depend on the type of dietary fats and the rate of fatty acid incorporation into the membrane. Sedentary rats fed a monounsaturated fatty acid-rich diet (virgin olive oil) showed a higher protection of their mitochondrial membranes against peroxidation than sedentary rats fed a polyunsaturated fatty acid-rich diet (sunflower oil). Rats subjected to training showed higher hydroperoxide contents than sedentary animals, and exhaustive effort enhanced the aforementioned results as well as in vitro peroxidation with a free radical inducer. This study suggests that peroxide levels first depend on tissue, then on diet and lastly on exercise, both in liver and muscle but not in heart. Finally, it appears that α-tocopherol is a less relevant protective agent against lipid peroxidation than monounsaturated fatty acids.

Plasma levels of von Willebrand factor in non-insulin-dependent diabetes mellitus are influenced by dietary monounsaturated fatty acids

We have previously demonstrated a lowering effect on von Willebrand Factor (vWF) of a diet rich in monounsaturated fatty acids (MUFA) as compared with a highcarbohydrate diet. In the present study 16 non-insulin dependent diabetic (NIDDM) subjects participated in a cross-over experiment on an out-patient basis comparing the effects on vWF of three weeks treatments with two diets similar in carbohydrate and protein content, one rich in MUFA (30 energy %) and one rich in polyunsaturated fatty acids (PUFA) (30 energy %). Before and on the last day of the two diets, the levels of vWF, fibrinogen, fibronectin and α 2-macroglobulin were measured. After 3 weeks diet intervention vWF levels were lower after the MUFA regimen compared with the PUFA diet (mean±SD) (1.15±0.36 vs 1.32±0.42 U/ml, p=0.003). Similar and unchanged levels of fibrinogen, fibronectin and α 2-macroglobulin were seen. In conclusion, three weeks on a diet rich in MUFA lowers vWF as compared with a PUFA rich diet, suggesting a beneficial effect of MUFA on the endothelium in NIDDM patients.

Antioxidant enzyme activities in the lymphoid organs and muscles of rats fed fatty acids-rich diets subjected to prolonged physical exercise-training

Rats weighing 45–50 g were fed 3 diets for 8 wk: a balanced control diet (CD) consisting of 4% fat (polyunsaturated/saturated fatty acids [P/S] ratio 2.9/1) and two fat-rich diets: polyunsaturated (UD)—P/S 7.6/1 and saturated (SD) P/S 0.3/1. After 8 wk feeding on the respective diets, rats were subjected to swimming for 90 min at 30°C daily, 5 d/wk for 8 wk. At the end of this period, the rats were killed and the lymphoid organs (LO—thymus, spleen, and mesenteric lymph nodes) and muscles (soleus and gastrocnemius) removed for the measurement of TBARs (Thiobarbituric Acid Reactant Substances) content and of the activities of antioxidant enzymes (CuZn- and Mn-Superoxide dismutase.—SOD—, catalase, and glutathione peroxidase). To evaluate the changes in the sites of generation of reducing equivalents involved in the formation of free radicals, the activities of citrate synthase and glucose-6-phosphate dehydrogenase were measured. The exercise-training clearly modified the enzyme activities and TBARs content of the lymphoid organs and skeletal muscles, but this effect was dependent upon the diet given to the rats. However, fatty acid rich diets had presented a more pronounced effect on the studied aspects than did physical activity. Although one could expect a summatory effect of polyunsaturated fatty acid-rich diet and exercise-training, swimming increased the activities of CuZn- and Mn-SOD in almost all tissues from the elevated level promoted by fat-rich diets.

Triacylglycerol metabolism by lymphocytes and the effect of triacylglycerols on lymphocyte proliferation.

This study investigates the ability of lymphocytes to utilize fatty acids originating from triacylglycerols and the effect of triacylglycerols upon mitogen-stimulated lymphocyte proliferation. Lymphocytes isolated from rat lymph nodes, spleen, thymus and lymphatic duct had a lipoprotein lipase activity of approx. 10 units/mg of protein, indicating that the fatty acids of circulating triacylglycerols are accessible to these cells. In culture lymph node lymphocytes hydrolysed triacylglycerols added to the medium as emulsions. Both non-esterified fatty acids and free glycerol appeared in the cell culture medium, but their concentrations indicated that a high proportion of each (65-90% of fatty acids and 60-80% of glycerol) was taken up by the cells. The incorporation and fate of triacylglycerol-fatty acids was studied by culturing the cells in the presence of tri[3H]oleoylglycerol or tri[14C]inoleoylglycerol. Both fatty acids were incorporated into lymphocyte lipids in a time-dependent manner; linoleic acid was incorporated at a significantly greater rate than oleic acid. The majority of oleic acid (greater than 70%) was incorporated into cellular triacylglycerol, while less than 10% was incorporated into phospholipids. In contrast, linoleic acid incorporation into cellular triacylglycerol never exceeded 25%, while up to 45% was incorporated into phospholipids. Triacylglycerols containing polyunsaturated fatty acids inhibited concanavalin A-stimulated lymphocyte proliferation in a concentration- and time-dependent manner; triacylglycerols containing saturated fatty acids or oleic acid were not inhibitory. Such direct effects of certain triacylglycerols on lymphocyte function may explain why some clinical trials of polyunsaturated fatty acid-rich diets have been successful in improving the condition of patients suffering from inflammatory diseases.

Effect of excess cholesterol on the protective effect of polyunsaturated fatty acid rich diets during myocardial infarction in conscious rats

Effect of excess cholesterol on the protective effect of polyunsaturated fatty acid rich diets during myocardial infarction in conscious rats