The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats.

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1ß), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Malondialdehyde and 4-hydroxy-2-hexenal are formed during dynamic gastrointestinal in vitro digestion of cod liver oils.

Marine long-chain polyunsaturated fatty acids (LC n-3 PUFA) are associated with reduced risk for inflammatory diseases, such as cardiovascular diseases and rheumatoid arthritis. These fatty acids, however, are rapidly oxidized, generating highly reactive malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE). These oxidation products may interact with DNA and proteins, thus possibly leading to impaired cell functions. Little is known about the formation of MDA, HHE and HNE in fish oil in the gastrointestinal (GI) tract. In this study, the effect of dynamic in vitro digestion of cod liver oil on the generation of MDA, HHE and HNE was evaluated using the TNO Gastro-Intestinal Model (tiny-TIM). Effects of pre-formed oxidation products, pre-emulsification of the oil, and addition of oxidants (EDTA and hemoglobin, Hb) on GI oxidation were evaluated. Formation of aldehydes occurred during GI digestion. However, only emulsified oil fortified with 11.5 µM Hb oxidized to a degree that overcame the dilution induced by gastric secretion, which caused increased aldehyde concentrations in gastric lumen up to 90 min. The maximum levels of aldehydes generated in this study were 24.5 µM MDA, 1.6 µM HHE and 0.07 µM HNE. Oils containing different amounts of pre-formed lipid oxidation products maintained the same oxidation ranking order during digestion, even though the relative changes were not directly proportional. Emulsification of the oil had an unclear effect in the gastric phase, but a pro-oxidative effect in the intestinal phase. In general, higher aldehyde levels were reached in the intestinal lumen than in the initial meal, demonstrating that GI digestion promotes oxidation. Hence, epithelial cells may be exposed to elevated amounts of reactive aldehydes for several hours after a meal containing fish oil.

Formation of reactive aldehydes (MDA, HHE, HNE) during the digestion of cod liver oil: comparison of human and porcine in vitro digestion models.

In this work, we investigated lipid oxidation of cod liver oil during gastrointestinal (GI) digestion using two types of in vitro digestion models. In the first type of model, we used human GI juices, while we used digestive enzymes and bile from porcine origin in the second type of model. Human and porcine models were matched with respect to factors important for lipolysis, using a standardized digestion protocol. The digests were analysed for reactive oxidation products: malondialdehyde (MDA), 4-hydroxy-trans-2-nonenal (HNE), and 4-hydroxy-trans-2-hexenal (HHE) by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS), and for free fatty acids (FFA) obtained during the digestion by gas chromatography-mass spectrometry (GC-MS). The formation of the oxidation products MDA, HHE, and HNE was low during the gastric digestion, however, it increased during the duodenal digestion. The formation of the oxidation products reached higher levels when digestive juices of human origin were used (60 µM of MDA, 9.8 µM of HHE, and 0.36 µM of HNE) [corrected] compared to when using enzymes and bile of porcine origin (0.96, and 1.6 µM of MDA; 0.16, and 0.23 µM of HHE; 0.026, [corrected] and 0.005 µM of HNE, respectively, in porcine models I and II). In all models, FFA release was only detected during the intestinal step, and reached up to 31% of total fatty acids (FA). The findings in this work may be of importance when designing oxidation oriented lipid digestion studies.

Effect of in vitro digested cod liver oil of different quality on oxidative, proteomic and inflammatory responses in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells.

BACKGROUND: Upon oxidation of the polyunsaturated fatty acids in fish oil, either before ingestion or, as recently shown, during the gastro-intestinal passage, a cascade of potentially cytotoxic peroxidation products, such as malondialdehyde and 4-hydroxy-2-hexenal, can form. In this study, we digested fresh and oxidised cod liver oils in vitro, monitored the levels of lipid peroxidation products and evaluated oxidative, proteomic and inflammatory responses to the two types of digests in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells. RESULTS: Digests of cod liver oil with 22-53 µmol L(-1) malondialdehyde and 0.26-3.7 µmol L(-1) 4-hydroxy-2-hexenal increased intracellular oxidation and cell energy metabolic activity compared to a digested blank in yeast cells and the influence of digests on mitochondrial protein expression was more pronounced for oxidised cod liver oil than fresh cod liver oil. The four differentially expressed and identified proteins were related to energy metabolism and oxidative stress response. Maturation of dendritic cells was affected in the presence of digested fresh cod liver oil compared to the digested blank, measured as lower CD86 expression. The ratio of secreted cytokines, IL-12p40/IL-10, suggested a pro-inflammatory effect of the digested oils in relation to the blank (1.47-1.67 vs. 1.07). CONCLUSION: Gastro-intestinal digestion of cod liver oil increases the amount of oxidation products and resulting digests affect oxidation in yeast and immunomodulation of dendritic cells.

Synthesis of 2-monoacylglycerols and structured triacylglycerols rich in polyunsaturated fatty acids by enzyme catalyzed reactions.

This paper studies the synthesis of structured triacylglycerols (STAGs) by a four-step process: (i) obtaining 2-monoacylglycerols (2-MAGs) by alcoholysis of cod liver oil with several alcohols, catalyzed by lipases Novozym 435, from Candida antartica and DF, from Rhizopus oryzae, (ii) purification of 2-MAGs, (iii) formation of STAGs by esterification of 2-MAGs with caprylic acid catalyzed by lipase DF, from R. oryzae, and (iv) purification of these STAGs. For the alcoholysis of cod liver oil, absolute ethanol, ethanol 96% (v/v) and 1-butanol were compared; the conditions with ethanol 96% were then optimized and 2-MAG yields of around 54-57% were attained using Novozym 435. In these 2-MAGs, DHA accounted for 24-31% of total fatty acids. In the operational conditions this lipase maintained a stable level of activity over at least 11 uses. These results were compared with those obtained with lipase DF, which deactivated after only three uses. The alcoholysis of cod liver oil and ethanol 96% catalyzed by Novozym 435 was scaled up by multiplying the reactant amounts 100-fold and maintaining the intensity of treatment constant (IOT=3g lipase h/g oil). In these conditions, the 2-MAG yield attained was about 67%; these 2-MAGs contained 36.6% DHA. The synthesized 2-MAGs were separated and purified from the alcoholysis reaction products by solvent extraction using solvents of low toxicity (ethanol and hexane); 2-MAG recovery yield and purity of the target product were approximately 96.4% and 83.9%, respectively. These 2-MAGs were transformed to STAGs using the optimal conditions obtained in a previous work. After synthesis and purification, 93% pure STAGs were obtained, containing 38% DHA at sn-2 position and 60% caprylic acid (CA) at sn-1,3 positions (of total fatty acids at these positions), i.e. the major TAG is the STAG with the structure CA-DHA-CA.

[Cod liver oil. A natural Vitamin D for preserving health]. / Csukamájolaj. Egy természetes D-vitamin az egészség megorzésére.

Vitamin D deficiency is pandemic in industrialized countries due to life-style changes. Recent studies suggest that besides bone-metabolism, vitamin D plays a central role in basic cell function like multiplication, differentiation and metabolism. This may explain that low vitamin D levels represent a risk factor for several apparently different diseases such as infective, autoimmune, neurodegenerative and cardiovascular diseases, as well as diabetes, osteoporosis and cancer. Accumulating evidences suggest that an adequate intake of vitamin D may significantly decrease prevalence and clinical outcome of these diseases. Estimated reduction of the economic burden might reach about 10 percent through normalizing vitamin D levels for these diseases. However, high doses of vitamin D monotherapy needs precaution for potential adverse effects and it should be substituted with the recommended doses of vitamin D in combination with synergistic vitamin A and omega 3 fatty acids, such as cod liver oil.

PAH biomarker responses in polar cod (Boreogadus saida) exposed to benzo(a)pyrene.

With expanding oil and gas activities into the Arctic region, there is a need to evaluate the induction capacity of polycyclic aromatic hydrocarbon (PAH) biomarkers on Arctic marine organisms and to test analytical methods that have been optimized for their temperate counterparts. Polar cod Boreogadus saida were injected intraperitoneally with cod liver oil (solvent control), 6.6+/-3.7, 85+/-48 or 378+/-190 microg kg(-1) wet weight of benzo(a)pyrene (B(a)P), or not injected (control), and liver and bile were sampled at 0 and 16 h and 1, 2, 4 and 7d. The mRNA expression of cytochrome P4501A1 (cyp1a1) and glutathione S-transferase (gst) genes showed a dose-dependent induction in the first 16 h following the injection and a return to basal levels after 4d. The aryl hydrocarbon receptor 2, however, showed no change in mRNA expression. The protein quantification of cytochrome P4501A (CYP1A), through Western blot analysis and the enzyme-linked immunosorbent assay (ELISA), presented similar but weaker and time-delayed responses (4-7d) compared to the gene (16 h to 2d). Ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) activities increased significantly at day 7 following the gene induction and increase in protein levels. Overall, these biomarkers showed dose-dependent but weak responses to B(a)P and low levels of bile metabolites. The mRNA expressions of oxidative stress genes, superoxide dismutases (sod(Cu/Zn) and sod(Mn)), catalase (cat) and glutathione peroxidase (gpx), were all up-regulated between 16 h and 2d of B(a)P exposure with cat (72-fold) and sod(Cu/Zn) (20-fold) giving the strongest responses in the highest dose. Finally, CAT protein level and enzyme activities showed less clear responses than the genes. The mRNA expression showed the earliest responses, followed by the protein levels. The enzymatic activities were the least sensitive and responded to the exposure after 7d. The study shows the induction capability of biomarkers in polar cod at very low bioavailable doses of B(a)P and provides new information on the selected biomarkers for use in oil monitoring in the Arctic.

Development of a low-cost technology for mass production of the free-living nematode Panagrellus redivivus as an alternative live food for first feeding fish larvae.

The free-living nematode Panagrellus redivivus is a suitable food source for first feeding fish. In the present report, a new method for the mass production of P. redivivus is presented. The technique involves multiplication of the nematode in monoxenic (single microorganism: Saccharomyces cerevisiae) solid culture (fluid media supported by 1- to 4-cm(3) sponge cubes) in autoclavable plastic bags (size range: 50 x 30 cm to 75 x 67 cm). Two growing media were tested: oat-meal medium (OM), which is an oat-based medium (16.7% oat-meal flour in 0.8% saline solution), and purified ingredient medium (PIM), a semi-synthetic medium (1.64% meat peptone, 0.94% yeast extract, 12.6% corn starch, 0.24% glucose, 1.48% sunflower oil, in 0.8% saline solution). The bags were inoculated with 350 nematodes/g medium. After an average period of 12 days (11-13 days) at 25 degrees C, the average yield (number of nematodes/g medium) was 241 x 10(3) for OM and 333 x 10(3) for PIM in 12-l bags (50 x 30 cm). The production scale has currently reached a bag volume of 50 l (75 x 67 cm); using PIM and the conditions described above, it was possible to harvest more than 1.3 x 10(9) nematodes/bag (291 x 10(3) nematodes/g medium). In PIM, when sun flower oil was replaced with the same amount of fish oil or cod liver oil, yields of 259 x 10(3) and 290 x 10(3) nematodes/g medium, respectively, were attained. The technology for mass production and formulation of P. redivivus should enable fish-hatchery operators to rely on a cheap, standardised, and permanently available live food product for first feeding fish larvae.

Fat-soluble vitamins in the maternal diet, influence of cod liver oil supplementation and impact of the maternal diet on human milk composition.

BACKGROUND/AIMS: To investigate lactating mothers' intake of fat-soluble vitamins in free-living subjects and to what extent cod liver oil supplementation influences the maternal intake in a population with common intake of cod liver oil. The impact of maternal diet on the concentration of fat-soluble vitamins in human milk was studied. METHODS: Dietary intake of 77 lactating women was investigated by 24-hour diet recalls and breast-milk samples were taken at the same occasions. Breast milk samples were analyzed for fat-soluble vitamins. RESULTS: The median intakes were 927 microg/day for vitamin A, 5.5 mg/day for vitamin E and 3.3 microg/day for vitamin D. Maternal vitamin A, E and D intakes were higher when the diet was supplemented with cod liver oil. Icelandic breast milk was found to have high contents of vitamin A and E. Only vitamin D was too low in breast milk to meet the recommended intake for infants. Retinylpalmitate in relation to lipids correlated with maternal vitamin A intake (r = 0.23, p < 0.05). The group with cod liver oil supplementation had significantly lower levels of gamma-tocopherol in breast milk (p < 0.01), whereas the supplementation did not affect other fat-soluble vitamins. CONCLUSION: The recommended intake of fat-soluble vitamins for lactating women can more easily be met with a cod liver oil supplementation than diet alone. Only vitamin D in human milk cannot meet the recommended intakes for infants, with normal breastfeeding. There is a relationship between the content of vitamins A and E in human milk and the maternal diet.

Estimation of essential fatty acid requirements of common carp larvae using semi-purified artificial diets.

Two trials were conducted with duplicate groups of (first feeding) carp larvae fed artificial dry diets based on casein and dextrin over 21 or 25 days. One control diet based on yeast was also tested. Survival, growth and fatty acid profiles of larvae were studied. In trial 1, (n-3) fatty acid requirement was estimated using diets supplemented or not with methyl linolenate or cod liver oil. After 21 days, the best survival and growth were observed in larvae fed the unsupplemented diet [(n-3) fatty acid level: 0.05%]. Survival and growth were not improved by higher levels of (n-3) fatty acids. In trial 2, (n-6) fatty acid requirement was estimated using diets with graded levels of methyl linolenate or peanut oil. After 25 days, the best survival and growth were obtained with diets supplemented with 0.25% methyl linolenate (total (n-6) fatty acid level: 1%) or with 1.25% peanut oil (total (n-6) fatty acid level: 0.89%). Survival and growth were not improved by higher levels of (n-6) fatty acids. Fatty acid composition of carp reflected that of the diets and also showed that carp larvae are capable of elongating and desaturating linolenic acid and linoleic acid in longer chain fatty acids.

The anti-oxidant activity of turmeric (Curcuma longa).

The turmeric anti-oxidant protein (TAP) had been isolated from the aqueous extract of turmeric. The anti-oxidant principle was found to be a heat stable protein. Trypsin treatment abolished the anti-oxidant activity. The anti-oxidant principle had an absorbance maximum at 280 nm. After gel filtration, the protein showed a 2-fold increase in anti-oxidant activity and showed 2 bands in the SDS-PAGE with approximate molecular weight range of 24,000 Da. The protein showed a concentration-dependent inhibitory effect on the promoter induced lipid peroxidation. A 50% inhibitory activity of lipid peroxidation was observed at a protein concentration of 50 micrograms/ml. Ca(2+)-ATPase of rat brain homogenate was protected to nearly 50% of the initial activity from the lipid peroxidant induced inactivation by this protein. This protection of Ca(2+)-ATPase activity was found to be associated with the prevention of loss of -SH groups.

Hydrolysis of fish oils containing polymers of triacylglycerols by pancreatic lipase in vitro.

Fish oils containing different levels of polymers of triacylglycerols formed during autoxidation were incubated with pancreatic lipase to establish whether these polymers are substrates for lipase hydrolysis. With oils containing low amounts (less than 4%) of triacylglycerol polymers as substrates, both triacylglycerols and polymers of triacylglycerols were almost completely hydrolyzed, and fatty acid monomers and monoacylglycerols were the major lipid products. Under the same incubation conditions, some triacylglycerols remained intact when highly oxidized oils containing 20 or 30% triacylglycerol polymers were the substrate. The fatty acid composition of these residual triacylglycerols was almost identical to that of triacylglycerols present at the start of the assay. When fish oil containing 30% triacylglycerol polymers was incubated with the lipase, the component triacylglycerols and polymers of triacylglycerols were hydrolyzed at similar rates, and fatty acid dimers were detected as a product. It is concluded that the high molecular weight polymers of triacylglycerols present in oxidized fish oils can be hydrolyzed by pancreatic lipase in vitro.

Response of urinary malondialdehyde to factors that stimulate lipid peroxidation in vivo.

Malondialdehyde (MDA) derivatives occur as normal constituents of rat and human urine. In a previous study, it was found that MDA excretion in rats is responsive to MDA intake and to certain factors that increase lipid peroxidation in vivo: vitamin E deficiency, iron administration and a high concentration of cod liver oil (CLO) fatty acids in the tissues. In the present study, the effect on MDA excretion of several additional dietary and endogenous factors was evaluated. The composition of dietary fatty acids had a major influence on MDA excretion in fed animals, being highest for animals fed n-3 fatty acids (20:5 and 22:6) from CLO, intermediate for those fed n-6 (18:2) acids from corn oil (CO) and lowest for those fed saturated acids from hydrogenated coconut oil (HCO). Diet was the main source of urinary MDA in all groups. Fasting produced a marked increase in urinary MDA, which tended to be higher in rats previously fed CLO. Fasting MDA excretion was not affected by the level of CO in the diet (5, 10 or 15%), indicating that feeding n-6 acids does not increase lipid peroxidation in vivo. Adrenocorticotropic hormone and epinephrine administration increased urinary MDA, further indicating that lipolysis either releases fatty acid peroxides from the tissues or increases the susceptibility of mobilized fatty acids to peroxidation. A decrease in fasting MDA excretion was observed in rats previously fed a high level of antioxidants (vitamin E + BHT + vitamin C) vs a normal level of vitamin E. MDA excretion increased following adriamycin and CCl4 administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Fish oil consumption and decreased risk of cardiovascular disease: a comparison of findings from animal and human feeding trials.

There is growing evidence that dietary n-3 polyunsaturated fatty acids (n-3 PUFAs), abundant in marine organisms, may reduce the development of cardiovascular disease. Because of this, results of laboratory animal and human volunteer feeding trials (using fatty fish, fish oils, or purified n-3 PUFAs) that have examined similar biochemical and metabolic parameters are compared. The limited data reveal that laboratory animal and human volunteers show many similar responses in certain parameters (ie, serum lipids, lipoproteins, trigacylglycerides, cholesterol, etc), to the consumption of n-3 PUFAs. The biochemical and metabolic changes observed are generally consistent with reduced development of cardiovascular disease. However, comparisons between species are limited because relatively few comparable feeding trials have focused on the effects of fish oils on thromboxane, prostacyclin, platelet aggregation, etc. Limitations of the studies and needed research are discussed.

Dietary modification of platelet and renal prostaglandins.

The effects of specific types of dietary fats on prostanoid biosynthesis, platelet function and the cardiovascular system are reviewed. Studies examining the influence of dietary modification of prostanoid synthesis on blood pressure regulation in normotensive and Goldblatt hypertensive rats showed that while dietary supplementation with either sunflower or linseed oil at 40% of energy respectively stimulated and inhibited tissue prostanoids in vitro and urinary PGE2 excretion in vivo, the development of 1 kidney, 1 clip hypertension was not altered in parallel. Rats on both oil rich diets did however, show an average lower blood pressure than animals on a standard diet. In order to minimise possible non-specific effects of large amounts of dietary fats, the effects on prostanoid metabolism of different oils at 5, 20 and 40% of energy in the diet were studied. While as little as 5% dietary supplements alter fatty acid and prostanoid synthesis in platelets, it appears that higher levels (at least 20%) are required to alter significantly renal prostaglandin metabolism.

Prostaglandin I3 is formed in vivo in man after dietary eicosapentaenoic acid.

Greenland Eskimos who live on a traditional marine diet rich in long chain omega 3-polyunsaturated fatty acids have a low incidence of cardiovascular disease and myocardial infarction. In their plasma and platelet lipids, arachidonic acid, the precursor of dienoic prostanoids, is partly replaced by eicosapentaenoic acid (C20:5, omega 3; EPA), the precursor of trienoic prostanoids. Studies with an Eskimo diet or a Western diet supplemented with sea fish or fish oil rich in EPA resulted in an 'Eskimo-like' pattern of plasma and platelet lipids. Moreover, less reactive platelets, a reduced ex vivo formation of proaggregatory thromboxane A2 and a blunted circulatory response to pressor hormones were reported. These favourable functional effects may be induced by a shift of prostanoid formation from the dienoic to the trienoic series. We show here that the major urinary metabolite of endogenous prostaglandin I3 is present in subjects that have ingested either cod liver oil (approximately 4 g EPA per day) or mackerel (approximately 10-15 g EPA per day). Our studies provide the first direct evidence for in vivo formation of prostaglandin I3 in man.

Dietary manipulation of prostaglandin and thromboxane synthesis in heart, aorta and blood platelets of the rat.

We conclude that dietary changes can have a profound influence on prostaglandin and thromboxane synthesis of organ systems. A better insight into underlying mechanisms is necessary before more definite advice with respect to feeding a linolenic acid and very long-chain polyunsaturated fatty acids as found in fish oils can be given.