Effects of n-3 and n-6 fatty acids on the activities and expression of hepatic antioxidant enzymes in autoimmune-prone NZBxNZW F1 mice

Correction of omega-3 fatty acid deficiency and improvement in disease activity in patients with systemic lupus erythematosus treated with krill oil concentrate: a multicentre, randomised, double-blind, placebo-controlled trial

OBJECTIVE

Omega-3 polyunsaturated fatty acids (PUFAs) play a critical role in regulating inflammation and lipid metabolism. This study sought to ascertain the frequency of omega-3 deficiency in patients with SLE and investigate whether supplementation with krill oil concentrate (KOC) could replenish omega-3 levels and decrease SLE disease activity.

METHODS

A multicentre, randomised, double-blind, placebo-controlled trial was conducted in adult patients with active SLE. Eligible patients were randomised to receive 4 g/day KOC or placebo (vegetable oil mixture) for the first 24 weeks, and thereafter patients could opt to enter an open-label extension. The primary end point was improvement of the red blood cell Omega-3 Index from baseline to week 24. Changes in clinical features, including SLE Disease Activity Index 2000 (SLEDAI-2K) disease activity scores, were also monitored.

RESULTS

Seventy-eight patients met eligibility criteria and were randomised to a treatment group (n=39 per group). The baseline Omega-3 Index in the total SLE cohort was a mean 4.43% (±SD 1.04%). After 4 weeks of KOC treatment, the Omega-3 Index rapidly increased to 7.17%±1.48% (n=38) and after 24 weeks to 8.05%±1.79% (n=25) (each p<0.001 vs baseline), whereas no significant change from baseline was noted in patients receiving placebo. Increases in the Omega-3 Index in KOC-treated patients persisted through week 48. After patients switched from placebo to KOC at 24 weeks, the mean Omega-3 Index showed a rapid and significant increase (from 4.63%±1.39% at week 24 (n=26) to 7.50%±1.75% at week 48 (n=12); p<0.001). Although there were no changes in disease activity in the study population overall, SLEDAI-2K scores decreased significantly in the KOC group during the 24-week randomised period among those who had high disease activity at baseline (SLEDAI-2K ≥9) (p=0.04, p=0.02 and p=0.01 vs placebo at 4, 8 and 16 weeks, respectively; n=9 per group). KOC was well-tolerated, with no significant safety concerns.

CONCLUSION

KOC corrected omega-3 deficiency in patients with SLE. Supplementation with KOC was safe and decreased disease activity in those with more active disease. These findings warrant further evaluation of omega-3 fatty acid supplementation with KOC in the management of SLE.

TRIAL REGISTRATION NUMBER

NCT03626311.

Effect of omega-3 polyunsaturated fatty acid supplementation on oxidative stress parameters and sex hormone levels of modern genotype sows

BACKGROUND

Sows are exposed to severe stress and hormonal challenges during their whole productive life. As polyunsaturated fatty acids play an important role in immune and reproductive functions, with a better understanding of their role in breeding sows' nutrition, improved performance and more sustainable pig production can be achieved.

OBJECTIVES

In this study, we investigated the effects of omega-6 and omega-3 fatty acid supplementation on the antioxidant status and hormone levels of sows.

METHODS

A total of 48 Danish Large white × Danish Landrace sows were supplemented either with sunflower oil (SO) as a control group or with fish oil (FO) as experimental group at the same dose of 10 g/kg feed. Blood samples were collected on day 14 of lactation, 5 days after weaning (insemination), and 30 days after insemination. To estimate antioxidant and reproductive effects, the amounts of reduced glutathione (GSH), thiobarbituric acid reactive substance, the activity of glutathione peroxidase (GPx), serum 17β oestradiol (E2), progesterone (P4), and 6-keto prostaglandin F1α (6-keto PGF1α) levels were investigated.

RESULTS

FO-based supplementation increased GPx activity on day 14 of lactation. Five days after weaning, the concentration of GSH in FO-fed sows was significantly higher than that in SO-fed sows. The E2 content of blood was significantly lower in the experimental group than in the control group for two of the three examined periods (day 14 of lactation and 30 days after insemination), whereas P4 levels were significantly higher in the experimental group 5 days after weaning. We found that 6-keto PGF1α levels were systematically lower in the experimental group throughout the trial.

CONCLUSIONS

This study provides evidence of the major impact of omega-6 and -3 fatty acids on the tested hormone levels, which serve as precursors for the production of E2 and P4 but have an opposite effect on PGF2α production.

Effect of Omega-3 on Recurrent Aphthous Stomatitis and Improvement Quality of Life

Objective

Recurrent aphthous stomatitis is one of the most common chronic inflammatory diseases in oral mucosa. Beneficial effects of omega-3 supplements on some inflammatory diseases have been proved. The aim of present study was to evaluate the effect of omega-3 supplements in recurrent aphthous stomatitis management and improve oral health-related quality of life.

Methods

In this double-blind clinical trial, 40 patients with minor recurrent aphthous stomatitis were randomly divided into case and control groups. The case group received 1000 mg capsules of omega-3, while the control group received placebo capsules for 6 months. The questionnaires of the ulcer severity score and the chronic oral mucosal disease questionnaire were filled by the patients in three steps, at the baseline session, after 3 months, and after 6 months. The data were analyzed by SPSS 22 software through ANOVA, Mann-Whitney, and chi-square tests. P < 0.05 was considered as significant.

Results

In the omega-3 group, the ulcer severity score showed significant reduction by three-month and six-month follow-ups (P < 0.0001, P < 0.0001, respectively). The mean score of the chronic oral mucosal disease questionnaire significantly improved by three-month and six-month follow-ups in the omega-3-receiving group.

Conclusion

Use of omega-3 oral supplements decreased the severity of aphthous ulcer and improved oral health-related quality of life.

Possible Protective Effects of TA on the Cancerous Effect of Mesotrione

The interaction of different food ingredients is now a very important and often emerging topic of research. Pesticides and their breakdown products, which may be carcinogenic, are one of the frequently occurring food contaminants. Compounds like traumatic acid (TA), which originates from plants, are beneficial, antioxidant, and anticancer food ingredients. Previously obtained results from our research group indicated antioxidative in normal human fibroblasts and prooxidative in cancer cells activity of TA. Since the literature data show an undoubted connection between the presence of pesticides in food and the increased incidence of different types of cancers, we attempted to clarify whether TA can abolish the effect of mesotrione stimulating the growth of cancer cells. In order to study the influence of mesotrione on breast cancer cells, we decided to carry out cytotoxicity studies of environmentally significant herbicide concentrations. We also analyzed the cytotoxicity of TA and mixtures of these two compounds. After selecting the most effective concentrations of both components tested, we conducted analyses of oxidative stress parameters and apoptosis in ZR-75-1 cells. The obtained results allow us to conclude that traumatic acid by stimulating oxidative stress and apoptosis contributes to inhibiting the growth and development of cells of the ZR-75-1 line strengthened by mesotrione. This may mean that TA is a compound with pro-oxidative and proapoptotic effects in cancer cells whose development and proliferation are stimulated by the presence of mesotrione. The presented results may be helpful in answering the question of whether herbicides and their residues in edibles may constitute potential threat for people diagnosed with cancer and whether compounds with proven pro-oxidative effects on cancer cells can have potential cytoprotective functions.

On growth performance, nutrient digestibility, blood T lymphocyte subsets, and cardiac antioxidant status of broilers

Different lipid sources differ in the fatty acid profiles and differently affect growth performance as well as immune function of broilers. The influences of different dietary lipid sources on growth performance, nutrient digestibility, blood T lymphocyte population, and cardiac antioxidant status were investigated of broilers. A total of 360 one-day-old male broilers (BW = 44 ± 3 g) were randomized into 3 treatment groups, consisting of 6 replicates with 20 birds in each group. Broilers received standard diets supplemented with 5% (wt/wt) of lard (LD, as a control diet), sesame oil (SO), or flaxseed oil (FO). Broilers in both SO and FO treatment groups had lower (P < 0.05) feed conversion ratios from 22 to 42 d and during the overall phase compared to those in LD treatment group. Meanwhile, the apparent total tract nutrient digestibility of crude fat in SO and FO treatment groups was higher than that in LD treatment group. Both FO and SO treatments decreased (P < 0.05) abdominal fat percentage compared to LD treatment. Total triglycerides and total cholesterol in chicken blood were decreased (P < 0.05) by SO and FO treatments compared to LD treatment. Feeding broilers with FO and SO led to a decrease (P < 0.05) in blood CD4⁺ T lymphocyte count and in CD4⁺:CD8⁺ ratio compared to LD treatment. Sesame oil and FO treatments increased cardiac glutathione peroxidase (P < 0.05) compared to LD treatment. It is concluded that addition of 5% SO and FO to the standard corn-soybean meal diet improved feed efficiency, increased the activities of cardiac glutathione peroxidase, and affected the T lymphocytes ratio of fast growing broilers.

Polyunsaturated fatty acids ameliorate aging via redox-telomere-antioncogene axis

Polyunsaturated fatty acids (PUFA), a group of nourishing and health-promoting nutrients, ameliorate age-related chronic diseases. However, how PUFA especially n-3 PUFA exert anti-aging functions remains poorly understood. Here we link fish oil, docosahexaenoic acid (DHA) and arachidonic acid (AA) to the aging etiology via a redox-telomere-antioncogene axis based on D-galactose-induced aging mice. Both fish oil and PUFA enhanced hepatic superoxide dismutase (SOD) and catalase activities and cardiac SOD activities within the range of 18%-46%, 26%-65% and 19%-58%, respectively, whereas reduced cerebral monoamine oxidase activity, plasma F₂-isoprostane level and cerebral lipid peroxidation level by 56%-90%, 20%-79% and 16%-54%, respectively. Thus, PUFA improve the in vivo redox and oxidative stress induced aging process, which however does not exhibit a dose-dependent manner. Notably, both PUFA and fish oil effectively inactivated testicular telomerase and inhibited c-Myc-mediated telomerase reverse transcriptase expression, whereas n-3 PUFA rather than n-6 PUFA protected liver and testes against telomere shortening within the range of 13%-25% and 25%-27%, respectively. Therefore, n-3 PUFA may be better at inhibiting the DNA damage induced aging process. Surprisingly, only DHA significantly suppressed cellular senescence pathway evidenced by testicular antioncogene p16 and p53 expression. This work provides evident support for the crosstalk between PUFA especially n-3 PUFA and the aging process via maintaining the in vivo redox homeostasis, rescuing age-related telomere attrition and down-regulating the antioncogene expression.

Carcass traits, meat quality, antioxidant status and antioxidant gene expression in muscle and liver of Hu lambs fed perilla seed

The effects of perilla (Perilla frutescens L.) seed on carcass traits, meat quality, antioxidant status and antioxidant gene expression in the liver and muscle of Hu lambs were investigated in this study. Sixty Hu lambs (23.02 ± 1.36 kg) were randomly divided into four experimental groups receiving diets containing 0%, 5%, 10% or 15% perilla seed (CD, 5%PFSD, 10%PFSD and 15%PFSD, respectively). The addition of perilla seed had no significant impacts on carcass traits (p > .05). There were no differences in pH, meat colour, drip loss, cooking loss or shear force among the four treatments (p > .05). Addition of perilla seed increased (p < .05) deposition of intramuscular lipids but had no effect on other chemical components in the longissimus dorsi (LD) (p > .05). The 15%PFSD diet decreased the total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content in the liver (p < .05 for both) but increased the activity of these antioxidant enzymes in LD (p < .05 for both). Compared to CD, addition of perilla seed increased superoxide dismutase (SOD) and glutathione peroxidase (GPX) expression in the liver and LD (p < .05 for all). These results indicate that perilla seed supplementation in lambs' diets can increase deposition of intramuscular lipids and improve muscular oxidative status and meat quality.

Effect of Dietary Fish Oil Replacement with Plant Oils on Growth Performance and Gene Expression in Juvenile Rainbow Trout (Oncorhynchus mykiss)

An eight-week feeding trial was conducted to evaluate the effects of total (100%) replacement of dietary fish oil with alternative lipid sources in juvenile rainbow trout. Six iso-nitrogenous and iso-lipidic experimental diets were formulated: CO (14%) – cod liver oil; SSO (14%) – safflower seed oil; SBO (14%) – soybean oil; LO (14%) – linseed oil; SBO (7%) + LO (7%) – a blend of soybean oil and linseed oil; and SSO (7%) + LO (7%) – a blend of safflower seed oil and linseed oil. Growth performance [specific growth rate (SGR), weight gain (WG), food conversion ratio (FCR) and survival rate (SR)], growth hormones [growth hormone (GH-I), insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II)], immune transforming growth factor-β (TGF-β) and antioxidant [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and glutathione S-transferase (GST)] response, and heat shock protein 70 (HSP70) mRNA levels were determined in muscle and liver. Our data indicated that final weight, weight gain, FCR and SGR showed significant difference among the six dietary treatments (P<0.05) while there were no significant differences in survival rate between the rainbow trout from supplement fed groups and control group. HSP70 mRNA level expression in muscle was higher in fish fed SSO (P<0.05) while highest level in liver was obtained from fish fed SBO compared to the other treatments (P<0.05). There were no significant differences among treatments for TGF-β mRNA expression level in muscle and liver. In conclusion, growth performance and expression levels of growth hormones, antioxidants, HSP70, except TGF-β were affected by five separate lipid sources. In addition, LO positively increased growth performance of juvenile rainbow trout by means of preventing oxidative stress and HSP70 and, enhanced expression of growth hormone related gene.

Lecithin derived from ω-3 PUFA fortified eggs decreases blood pressure in spontaneously hypertensive rats

Hypertension is the most common risk factor for stroke, coronary heart disease and heart failure, which are the leading causes of death worldwide. Dietary patterns and supplements intakes are becoming important factors in the hypertension. The aim of this study was to estimate the effects of new generation egg yolk phospholipids rich in lecithin (SL) esterified with omega-3 and omega-6 fatty acids on blood pressure in hypertensive rats (SHR). Here we have reported that lecithin (SL) derived from egg yolk lowers blood pressure in pathology of hypertension. The SHR rats treated with SL had significantly lower blood pressure than control group (157/104 vs. 178/121 mmHg; P < 0.05) and down-regulated mesenteric artery over-response to norepinephrine and potassium chloride, giving similar arterial response as for normotensive Wistar Kyoto rats (WKY). Hypertensive rats treated by SL demonstrated significantly lower serum level of inflammatory factors. This work also indicates that SL treatment lowers heart rate and reduces the serum level of oxidative stress marker - nitrotyrosine - by 30–34% in both hypertensive and normotensive animals. Phospholipids with lecithin derived from PUFA fortified eggs may be a valuable dietary supplement in prophylaxis of hypertension and in patients with hypertension, however, this requires further studies on humans.

Fish oil diet may reduce inflammatory levels in the liver of middle-aged rats

The impact of dietary soybean oil, lard and fish oil on physiological responses in middle age is little studied. In this study, we investigated the changes of oxidative stress, inflammatory cytokines, telomere length, and age-related gene expression in the liver of middle-aged rats in response to the above three fat diets. Male Sprague Dawley rats (12 months old) were fed AIN-93M diets for 3 months, in which soybean oil was equivalently replaced by lard or fish oil. As compared to the lard diet, intake of fish oil diet significantly decreased body weight gain, white blood cell count, and levels of hepatic triacylglycerol, total cholesterol, fat accumulation, low-density lipoprotein, oxidative stress and inflammatory cytokines (P < 0.05), but increased telomere length (P < 0.05). On the other hand, lard diet and soybean oil diet showed great similarity in the above variables. PCR array analysis further indicated that fish oil diet significantly down-regulated gene expression related to inflammatory response, apoptosis, DNA binding, proteostasis and telomere attrition. Differentially expressed genes were enriched in the complement and coagulation cascades pathways. Such physiological and molecular responses could be due to different fatty acid composition in fish oil, lard and soybean oil.

Dietary omega-3 but not omega-6 fatty acids down-regulate maternal dyslipidemia induced oxidative stress: A three generation study in rats

BACKGROUND

Maternal nutrition modulates fetal metabolic programming and development later. Maternal dyslipidemia effects on oxidative stress (OS) in offsprings and its modulation by dietary fatty acids over generations remains to be elucidated. The objective of present study was to assess the long-term (three generations) effect of omega-3 fatty acids on OS under dyslipidemia.

METHODS

Weanling female Wistar rats were fed with control diet (7% lard), high fat diet (35% lard, HFL), high fat with fish oil (21% fish oil + 14% lard, HFF), high fat with canola oil (21% canola oil + 14% lard, HFC) and high fat with sunflower oil (21% sunflower oil + 14% lard, HFS). Following 60 days feeding, the female rats were mated with sexually matured males (fed normal chow diet) and continued with the above diet regimen during pregnancy and lactation. The pups after lactation were continued with their maternal diet for 60 days and subjected to mating and feeding trial as above for two generations. Serum lipid profiles, OS markers (lipid peroxidation, nitric oxide release and protein carbonyl) and antioxidant defence enzymes (catalase, SOD, glutathione peroxidase and glutathione transferase) were assessed in serum, liver and uterus of rats fed on experimental and control diets for three generations.

RESULTS

Feeding HFL diet increased blood lipids, OS and lowered the antioxidant enzymes activity in serum, liver and uterus (p < 0.05). The reduction in the antioxidant enzymes in HFL group were higher in third followed by second generation compared to first generation (p < 0.05). Omega-3 fatty acids prevented the dyslipidemia induced loss of antioxidant enzyme activities in serum, liver and uterus.

CONCLUSIONS

Our data show for the first time that offsprings born to dyslipidemic mothers' exhibit diminished enzymatic antioxidant defence and its progressive reduction in future generation, and dietary omega-3 fatty acids restore the enzymatic antioxidant defence in offsprings and suppress the markers of OS.

Up-Regulation of Mitochondrial Antioxidant Superoxide Dismutase Underpins Persistent Cardiac Nutritional-Preconditioning by Long Chain n-3 Polyunsaturated Fatty Acids in the Rat

Reactive oxygen species paradoxically underpin both ischaemia/reperfusion (I/R) damage and ischaemic preconditioning (IPC) cardioprotection. Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) are highly susceptible to peroxidation, but are paradoxically cardioprotective. This study tested the hypothesis that LCn-3 PUFA cardioprotection is underpinned by peroxidation, upregulating antioxidant activity to reduce I/R-induced lipid oxidation, and the mechanisms of this nutritional preconditioning contrast to mechanisms of IPC. Rats were fed: fish oil (LCn-3 PUFA); sunflower seed oil (n-6 PUFA); or beef tallow (saturated fat, SF) enriched diets for six weeks. Isolated hearts were subject to: 180 min normoxic perfusion; a 30 min coronary occlusion ischaemia protocol then 120 min normoxic reperfusion; or a 3 × 5 min global IPC protocol, 30 min ischaemia, then reperfusion. Dietary LCn-3 PUFA raised basal: membrane docosahexaenoic acid (22:6n-3 DHA); fatty acid peroxidisability index; concentrations of lipid oxidation products; and superoxide dismutase (MnSOD) activity (but not CuZnSOD or glutathione peroxidase). Infarct size correlated inversely with basal MnSOD activity (r² = 0.85) in the ischaemia protocol and positively with I/R-induced lipid oxidation (lipid hydroperoxides (LPO), r² = 0.475; malondialdehyde (MDA), r² = 0.583) across ischaemia and IPC protocols. While both dietary fish oil and IPC infarct-reduction were associated with reduced I/R-induced lipid oxidation, fish oil produced nutritional preconditioning by prior LCn-3 PUFA incorporation and increased peroxidisability leading to up-regulated mitochondrial SOD antioxidant activity.

Effect of feeding lipids recovered from fish processing waste by lactic acid fermentation and enzymatic hydrolysis on antioxidant and membrane bound enzymes in rats

Fish oil recovered from fresh water fish visceral waste (FVW-FO) through lactic acid fermentation (FO-LAF) and enzymatic hydrolysis (FO-EH) were fed to rats to study their influence on lipid peroxidation and activities of antioxidant and membrane bound enzyme in liver, heart and brain. Feeding of FO-LAF and FO-EH resulted in increase (P < 0.05) in lipid peroxides level in serum, liver, brain and heart tissues compared to ground nut oil (control). Activity of catalase (40-235 %) and superoxide dismutase (17-143 %) also increased (P < 0.05) with incremental level of EPA + DHA in diet. The increase was similar to cod liver oil fed rats at same concentration of EPA + DHA. FO-LAF and FO-EH increased (P < 0.05) the Na(+)K(+) ATPase activity in liver and brain microsomes, Ca(+)Mg(+) ATPase in heart microsome and acetylcholine esterase in brain microsomes when fed with 5 % EPA + DHA. There was also significant change in fatty acid composition and cholesterol/phospholipid ratio in microsomes of rat fed with FVW-FO. Feeding FVW-FO recovered by biotechnological approaches enhanced the activity of antioxidant enzymes in tissues, modulates the activities of membrane bound enzymes and improved the fatty acid composition in microsomes of tissues similar to CLO. Utilization of these processing wastes for the production of valuable biofunctional products can reduce the mounting economic values of fish oil and minimize the environmental pollution problems.

Antioxidants and antioxidant enzymes status of rats fed on n-3 PUFA rich Garden cress (Lepidium Sativum L) seed oil and its blended oils

Garden cress (Lepidium sativum L) seed oil (GCO) is a rich source of α-linolenic acid (ALA, 33.6 %) and the oil has a fairly balanced SFA, MUFA and PUFA ratio. In this study we have investigated the effect of GCO and its blends with n-6 PUFA rich edible vegetable oils sunflower oil (SFO), rice bran oil (RBO) and sesame oil (SESO) on antioxidant status of oils and antioxidative enzymes in Wistar rats. Physical blending of GCO with n-6 PUFA rich vegetable oils (SFO, RBO and SESO) increased content of natural antioxidants such as tocopherols, oryzanol and lignans, decreased the n-6/n-3 PUFA ratio and improved the radical scavenging activity of blended oils. Dietary feeding of GCO and its blended oils for 60 days, increased the tocopherols levels (12.2-21.6 %) and activity of antioxidant enzymes namely catalase, glutathione peroxidase (GPx), but did not affect the activity of glutathione reductase (GR), superoxide dismutase (SOD) and glutathione S-transferase (GST) in liver compared to native oil fed rats. Thus, blending of GCO with other vegetable oil decreased n-6/n-3 PUFA ratio (>2.0) and dietary feeding of GCO blended oils increased the antioxidant status and activity of antioxidant enzymes (catalase and GPx) in experimental rats.

Neuroprotective properties of the marine carotenoid astaxanthin and omega-3 fatty acids, and perspectives for the natural combination of both in krill oil

The consumption of marine fishes and general seafood has long been recommended by several medical authorities as a long-term nutritional intervention to preserve mental health, hinder neurodegenerative processes, and sustain cognitive capacities in humans. Most of the neurological benefits provided by frequent seafood consumption comes from adequate uptake of omega-3 and omega-6 polyunsaturated fatty acids, n-3/n-6 PUFAs, and antioxidants. Optimal n-3/n-6 PUFAs ratios allow efficient inflammatory responses that prevent the initiation and progression of many neurological disorders. Moreover, interesting in vivo and clinical studies with the marine antioxidant carotenoid astaxanthin (present in salmon, shrimp, and lobster) have shown promising results against free radical-promoted neurodegenerative processes and cognition loss. This review presents the state-of-the-art applications of n-3/n-6 PUFAs and astaxanthin as nutraceuticals against neurodegenerative diseases associated with exacerbated oxidative stress in CNS. The fundamental “neurohormesis” principle is discussed throughout this paper. Finally, new perspectives for the application of a natural combination of the aforementioned anti-inflammatory and antioxidant agents (found in krill oil) are also presented herewith.

Efficacy of omega-3 in treatment of recurrent aphthous stomatitis and improvement of quality of life: a randomized, double-blind, placebo-controlled study

OBJECTIVE

This study assessed the effects of systemic omega-3 on the treatment of recurrent aphthous stomatitis and on the improvement of quality of life.

STUDY DESIGN

Fifty participants were randomly assigned to receive either omega-3 (1 g, 3 times daily) or placebo for 6 months. Assessment of outcome measures including monthly number of new ulcers, average duration of ulcer episodes, and pain level of ulcers was carried out at baseline and monthly for 6 months. Analysis of potential impact on quality of life using the Oral Health Impact Profile 14 was carried out at baseline and 6 months.

RESULTS

Daily omega-3 treatment achieved a significant reduction in number of ulcers, duration of ulcers, and level of pain by 3 months that persisted for 6 months. Mean score on Oral Health Impact Profile 14 also significantly improved by 6 months.

CONCLUSIONS

A daily omega-3 regimen shows promise as therapy for treatment and management of patients with recurrent aphthous stomatitis.

Concentrated fish oil (Lovaza(R)) extends lifespan and attenuates kidney disease in lupus-prone short-lived (NZBxNZW)F1 mice

A growing number of reports indicate that anti-inflammatory actions of fish oil (FO) are beneficial against systemic lupus erythematosus (SLE). However, the majority of pre-clinical studies were performed using 5-20% FO, which is higher than the clinically relevant dose for lupus patients. The present study was performed in order to determine the effective low dose of FDA-approved concentrated FO (Lovaza®) compared to the commonly used FO-18/12 (18-Eicosapentaenoic acid [EPA]/12-Docosahexaenoic acid [DHA]). We examined the dose-dependent response of Lovaza® (1% and 4%) on an SLE mouse strain (NZBxNZW)F1 and compared the same with 1% and 4% placebo, as well as 4% FO-18/12, maintaining standard chow as the control. Results show for the first time that 1% Lovaza® extends maximal lifespan (517 d) and 4% Lovaza® significantly extends both the median (502 d) and maximal (600 d) life span of (NZBxNZW)F1 mice. In contrast, FO-18/12 extends only median lifespan (410 d) compared to standard chow diet (301 d). Additionally, 4% Lovaza® significantly decreased anti-dsDNA antibodies, reduced glomerulonephritis and attenuated lipopolysaccharide-induced pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in splenocytes compared to placebo. 4% Lovaza® was also shown to reduce the expression of inflammatory cytokines, including IL-1β, IL-6 and TNF-α, while increasing renal anti-oxidant enzymes in comparison to placebo. Notably, NFκB activation and p65 nuclear translocation were lowered by 4% Lovaza® compared to placebo. These data indicate that 1% Lovaza® is beneficial, but 4% Lovaza® is more effective in suppressing glomerulonephritis and extending life span of SLE-prone short-lived mice, possibly via reducing inflammation signaling and modulating oxidative stress.

Relationship between oxidizable fatty acid content and level of antioxidant glutathione peroxidases in marine fish

Biological membranes can be protected from lipid peroxidation by antioxidant enzymes including catalase (CAT) and selenium-dependent glutathione peroxidases 1 and 4 (GPx1 and GPx4). Unlike GPx1, GPx4 can directly detoxify lipid hydroperoxides in membranes without prior action of phospholipase A(2). We hypothesized that (1) GPx4 is enhanced in species that contain elevated levels of highly oxidizable polyunsaturated fatty acids (PUFA) and (2) activities of antioxidant enzymes are prioritized to meet species-specific oxidative stresses. In this study we examined (i) activities of the oxidative enzyme citrate synthase (CS) and antioxidant (CAT, GPx1 and GPx4) enzymes, (ii) GPx4 protein expression, and (iii) phospholipid composition in livers of five species of marine fish (Myxine glutinosa, Petromyzon marinus, Squalus acanthias, Fundulus heteroclitus and Myoxocephalus octodecemspinosus) that contain a range of PUFA. GPx4 activity was, on average, 5.8 times higher in F. heteroclitus and S. acanthias than in the other three marine fish species sampled. Similarly, activities of CAT and GPx1 were highest in S. acanthias and F. heteroclitus, respectively. GPx4 activity for all species correlates with membrane unsaturation, as well as oxidative activity as indicated by CS. These data support our hypothesis that GPx4 level in marine fish is a function, at least in part, of high PUFA content in these animals. GPx1 activity was also correlated with membrane unsaturation, indicating that marine species partition resources among glutathione-dependent defenses for protection from the initial oxidative insult (e.g. H(2)O(2)) and to repair damaged lipids within biological membranes.

Alternative therapies for the prevention and treatment of osteoporosis

Osteoporosis is a medical condition that affects millions of men and women. People with this condition have low bone mass, which places them at increased risk for bone fracture after minor trauma. The surgeries and treatments required to repair and heal bone fractures involve long recovery periods and can be expensive. Because osteoporosis occurs frequently in the elderly, the financial burden it places on society is likely to be large. In the United States, the Food and Drug Administration has approved several drugs for use in the prevention and treatment of osteoporosis. However, all of the currently available agents have severe side effects that limit their efficacy and underscore the urgent need for new treatment options. One promising approach is the development of alternative (nonpharmaceutical) strategies for bone maintenance, as well as for the prevention and treatment of osteoporosis. This review examines the currently available nonpharmaceutical alternatives that have been evaluated in in vitro and in vivo studies. Certain plants from the following families have shown the greatest benefits on bone: Alliceae, Asteraceae, Thecaceae, Fabaceae, Oleaceae, Rosaceae, Ranunculaceae, Vitaceae, Zingiberaceae. The present review discusses the most promising findings from studies of these plant families.

Different sources of omega-3 polyunsaturated fatty acids affects apparent digestibility, tissue deposition, and tissue oxidative stability in growing female rats

Background

Numerous health benefits associated with increased omega-3 polyunsaturated fatty acid (n-3 PUFA) consumption has lead to an increasing variety of available n-3 PUFA sources. However, sources differ in the type, amount, and structural form of the n-3 PUFAs. Therefore, the objective of this study was to determine the effect of different sources of ω-3 PUFAs on digestibility, tissue deposition, eicosanoid metabolism, and oxidative stability.

Methods

Female Sprague-Dawley rats (age 28 d) were randomly assigned (n = 10/group) to be fed a high fat 12% (wt) diet consisting of either corn oil (CO) or n-3 PUFA rich flaxseed (FO), krill (KO), menhaden (MO), salmon (SO) or tuna (TO) oil for 8 weeks. Rats were individually housed in metabolic cages to determine fatty acid digestibility. Diet and tissue fatty acid composition was analyzed by gas chromatography and lipid classes using thin layer chromatography. Eicosanoid metabolism was determined by measuring urinary metabolites of 2-series prostaglandins (PGs) and thromoboxanes (TXBs) using enzyme immunoassays. Oxidative stability was assessed by measuring thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) using colorimetric assays. Gene expression of antioxidant defense enzymes was determined by real time quantitative polymerase chain reaction (RT-qPCR).

Results

Rats fed KO had significantly lower DHA digestibility and brain DHA incorporation than SO and TO-fed rats. Of the n-3 PUFA sources, rats fed SO and TO had the highest n-3 PUFAs digestibility and in turn, tissue accretion. Higher tissue n-3 LC-PUFAs had no significant effect on 2-series PG and TXB metabolites. Despite higher tissue n-3 LC-PUFA deposition, there was no increase in oxidation susceptibility indicated by no significant increase in TBARS or decrease in TAC and gene expression of antioxidant defense enzymes, in SO or TO-fed rats.

Conclusions

On the basis that the optimal n-3 PUFA sources should provide high digestibility and efficient tissue incorporation with the least tissue lipid peroxidation, TO and SO appeared to be the most beneficial of the n-3 PUFAs sources evaluated in this study.

Dietary n-3 polyunsaturated fatty acids and the paradox of their health benefits and potential harmful effects

There is some evidence to support the toxicity of polyunsaturated fatty acids (PUFAs) and their oxidative products, suggesting their involvement in the pathogenesis of different chronic diseases, including cancer. It has been shown that products of PUFA oxidation may exert a carcinogenic action by forming mutagenic adducts with DNA. However, a large amount of evidence accumulated over several decades has indicated the beneficial effects of administration of n-3 PUFAs in the prevention and therapy of a series of diseases. In particular, there is much evidence that n-3 PUFAs exert anti-inflammatory and antineoplastic effects, whereas n-6 PUFAs promote inflammation and carcinogenesis. In our tissues, both of the two classes of PUFAs can be converted into bioactive products, incorporated into membrane phospholipids or bound to membrane receptors, where they may alter, often in opposite ways, transduction pathways and affect important biological processes, such as cell death and survival, inflammation, and neo-angiogenesis. In the present review, we intend to shed light on the paradox of the coexisting healthy and toxic effects of n-3 PUFAs, focusing on their possible pro-oxidant cytotoxic and carcinogenic effect, in order to understand if their increased intake, recommended by a number of health agencies worldwide and promoted by nutraceutical producers, may or may not represent a hazard to human health.

n-3 Fatty acids uniquely affect anti-microbial resistance and immune cell plasma membrane organization

It is now well established that dietary lipids are incorporated into macrophage and T-cell membrane microdomains, altering their structure and function. Within cell membranes, there are specific detergent-resistant domains in which key signal transduction proteins are localized. These regions are classified as "lipid rafts". Rafts are composed mostly of cholesterol and sphingolipids and therefore do not integrate well into the fluid phospholipid bilayers causing them to form microdomains. Upon cell activation, rafts compartmentalize signal-transducing molecules, thus providing an environment conducive to signal transduction. In this review, we discuss recent novel data describing the effects of n-3 PUFA on alterations in the activation and functions of macrophages and T-cells. We believe that the modifications in these two disparate immune cell types are linked by fundamentally similar changes in membrane lipid composition and transmembrane signaling functions. We conclude that the outcomes of n-3 PUFA-mediated immune cell alterations may be beneficial (e.g., anti-inflammatory) or detrimental (e.g., loss of microbial immunity) depending upon the cell type interrogated.

The fat-1 transgene in mice increases antioxidant potential, reduces pro-inflammatory cytokine levels, and enhances PPAR-gamma and SIRT-1 expression on a calorie restricted diet

Both n-3 fatty acids (FA) and calorie-restriction (CR) are known to exert anti-inflammatory and anti-oxidative effects in animals and humans. In this study, we investigated the synergistic anti-inflammatory and anti-oxidative capacity of n-3 FA and CR using Fat-1 transgenic mice (Fat-1) that are capable of converting n-6 FA to n-3 FA endogenously. Wild type (WT) and Fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) AIN-93 diet supplemented with 10% corn oil (rich in n-6 FA) for 5 months. Significantly lower levels of n-6/n-3 FA ratio were observed in serum, muscle and liver of Fat-1 mice fed AL or CR as compared to that of WT mice fed AL or CR. Muscle catalase (CAT), super oxide dismutase (SOD), glutathione peroxidase (GPX) activities, and liver CAT and SOD activities were found higher in Fat-1 mice as compared to that of WT mice. These activities were more pronounced in Fat-1/CR group as compared to other groups. Serum pro-inflammatory markers, such as tumor necrosis factor (TNF)α, interleukin (IL)-1β and IL-6 were found lower in Fat-1 mice, as compared to that of WT mice. This anti-inflammatory effect was also more pronounced in Fat-1/CR group as compared to that of other groups. Furthermore, significantly higher levels of peroxisome proliferator-activated receptor (PPA R)gamma and life prolonging gene, sirtuin (SIRT)-1 expression were found in liver of Fat-1/CR mice, as compared to that of WT/CR mice. These data suggest that n-3 FA along with moderate CR may prolong lifespan by attenuating inflammation and oxidative stress.

Alternative therapies: what role do they have in the management of lupus?

Systemic lupus erythematosus (SLE) is an autoimmune disease with higher morbidity and mortality among ethnic Chinese patients than Whites. Corticosteroid and other immunosuppressive drugs, including cyclophosphamide, azathioprine, and hydroxychloroquine are traditional therapies for this disease. Since the year 2000, mycophenolate mofetil and rituximab have been widely used in refractory SLE or severe lupus nephritis. Because the high disease activity remains, even after active therapy, and serious side effects from Western medicines may develop, more than 40% of SLE patients in Western countries are pursuing complementary and alternative therapies (CATs). CAT remedies are multiplex, and include herbal medicines, diets and vitamins, acupuncture, chiropractice, folk medicine, massage, spiritual healing, etc. Many herbal formulas have been used but in general their efficacy in treating lupus is doubted because of the lack of strong evidence. Tripterygium (T2) has demonstrated good efficacy in rheumatoid arthritis (RA) and SLE, but widespread use is limited due to the side effects. Through randomized clinical trials, we hope in the future that some Chinese medicines may be found helpful as CATs for SLE.

Docosahexaenoic acid-enriched fish oil attenuates kidney disease and prolongs median and maximal life span of autoimmune lupus-prone mice

The therapeutic efficacy of individual components of fish oils (FOs) in various human inflammatory diseases still remains unresolved, possibly due to low levels of n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) or lower ratio of DHA to EPA. Because FO enriched with DHA (FO-DHA) or EPA (FO-EPA) has become available recently, we investigated their efficacy on survival and inflammatory kidney disease in a well-established animal model of human systemic lupus erythematosus. Results show for the first time that FO-DHA dramatically extends both the median (658 d) and maximal (848 d) life span of (NZB x NZW)F1 (B x W) mice. In contrast, FO-EPA fed mice had a median and maximal life span of approximately 384 and 500 d, respectively. Investigations into possible survival mechanisms revealed that FO-DHA (versus FO-EPA) lowers serum anti-dsDNA Abs, IgG deposition in kidneys, and proteinuria. Further, FO-DHA lowered LPS-mediated increases in serum IL-18 levels and caspase-1-dependent cleavage of pro-IL-18 to mature IL-18 in kidneys. Moreover, FO-DHA suppressed LPS-mediated PI3K, Akt, and NF-kappaB activations in kidney. These data indicate that DHA, but not EPA, is the most potent n-3 fatty acid that suppresses glomerulonephritis and extends life span of systemic lupus erythematosus-prone short-lived B x W mice, possibly via inhibition of IL-18 induction and IL-18-dependent signaling.

Fish oil targets PTEN to regulate NFkappaB for downregulation of anti-apoptotic genes in breast tumor growth

The molecular mechanism for the beneficial effect of fish oil on breast tumor growth is largely undefined. Using the xenograft model in nude mice, we for the first time report that the fish oil diet significantly increased the level of PTEN protein in the breast tumors. In addition, the fish oil diet attenuated the PI 3 kinase and Akt kinase activity in the tumors leading to significant inhibition of NFkappaB activation. Fish oil diet also prevented the expression of anti-apoptotic proteins Bcl-2 and Bcl-XL in the breast tumors with concomitant increase in caspase 3 activity. To extend these findings we tested the functional effects of DHA and EPA, the two active omega-3 fatty acids of fish oil, on cultured MDA MB-231 cells. In agreement with our in vivo data, DHA and EPA treatment increased PTEN mRNA and protein expression and inhibited the phosphorylation of p65 subunit of NFkappaB in MDA MB-231 cells. Furthermore, DHA and EPA reduced expression of Bcl-2 and Bcl-XL. NFkappaB DNA binding activity and NFkappaB-dependent transcription of Bcl-2 and Bcl-XL genes were also prevented by DHA and EPA treatment. Finally, we showed that PTEN expression significantly inhibited NFkappaB-dependent transcription of Bcl-2 and Bcl-XL genes. Taken together, our data reveals a novel signaling pathway linking the fish oil diet to increased PTEN expression that attenuates the growth promoting signals and augments the apoptotic signals, resulting in breast tumor regression.

Effects of exogenous antioxidants on dietary iron overload

In dietary iron overload, excess hepatic iron promotes liver damage. The aim was to attenuate free radical-induced liver damage using vitamins. Four groups of 60 Wistar rats were studied: group 1 (control) was fed normal diet, group 2 (Fe) 2.5% pentacarbonyl iron (CI) followed by 0.5% Ferrocene, group 3 (Fe + V gp) CI, Ferrocene, plus vitamins A and E (42× and 10× RDA, respectively), group 4 (Fe – V gp) CI, Ferrocene diet, minus vitamins A and E. At 20 months, glutathione peroxidase (GPx), superoxide dismutase (SOD), Oxygen Radical Absorbance Capacity (ORAC), Ames mutagenicity test, AST, ALT and 4-hydroxynonenal (4-HNE) immunohistochemistry were measured. 8OHdG levels of the Fe + V and Fe – V groups were 346 ± 117 and 455 ± 151, ng/g w.wt, respectively. Fe + V and Fe – V differences were significant (p<0.005). A positive correlation between DNA damage and mutagenesis existed (p<0.005) within the iron-fed gps. AST levels for Fe + V and Fe – V groups were 134.6 ± 48.6 IU and 202.2 ± 50.5 IU, respectively. Similarly, ALT levels were 234.6 ± 48.3 IU and 329.0 ± 48.6 IU, respectively. However, Fe – V and Fe + V groups transaminases were statistically insignificant. 4-HNE was detected in Fe + V and Fe – V gp livers. Vitamins A and E could not prevent hepatic damage.

Krill for Human Consumption: Nutritional Value and Potential Health Benefits

The marine crustacean krill (order Euphausiacea) has not been a traditional food in the human diet. Public acceptance of krill for human consumption will depend partly on its nutritive value. The aim of this article is to assess the nutritive value and potential health benefits of krill, an abundant food source with high nutritional value and a variety of compounds relevant to human health. Krill is a rich source of high-quality protein, with the advantage over other animal proteins of being low in fat and a rich source of omega-3 fatty acids. Antioxidant levels in krill are higher than in fish, suggesting benefits against oxidative damage. Finally, the waste generated by the processing of krill into edible products can be developed into value-added products.

Catalase -262C>T polymorphism in systemic lupus erythematosus in Poland

It has been reported that reactive oxygen species contribute to pathogenesis of systemic lupus erythematosus (SLE). Catalase (CAT) -330C>T transition, known also as -262C>T, generates three genotypes. The CAT -330CC genotype is associated with a significantly lower CAT expression in comparison to -330CT and -330CT genotypes. Therefore, using restriction length fragment polymorphism analysis, we compared the frequencies of CAT -330C>T polymorphic variants between SLE patients (n = 102) and controls (n = 199). We did not observe significant differences in the prevalence of CAT -330C>T polymorphic variants in SLE patients and controls. However, we found that the CAT -330CC genotype (recessive model) showed a significant association with thrombocytopenia OR = 7.314 (1.977-27.057, P = 0.0017). We also observed that the CAT -330CC genotype (recessive model) is linked with leukopenia OR = 3.232 (1.361-7.676, P = 0.0118), renal manifestations OR = 2.403 (1.085-5.321, P = 0.0471) and presence of anti-snRNP Ab OR = 4.206 (95% CI = 1.405-12.590, P = 0.0131), and anti-Scl-70 Ab, OR = 3.143 (95% CI = 1.171-8.433, P = 0.0343) in SLE patients. Our findings suggest that the CAT -330CC genotype may contribute to some clinical manifestations in patients with SLE.

Simulated hyperglycemia in rat cardiomyocytes: A proteomics approach for improved analysis of cellular alterations

Diabetic hyperglycemia can lead to stress-related cellular apoptosis of cardiac tissue. However, the mechanism by which hyperglycemia inflicts this damage on the structure and function of the heart is unclear. In this study, we examined the relationship between proteome alterations, mitochondrial function, and major biochemical and electrophysiological changes affecting cardiac performance during simulated short-term hyperglycemia. Two-dimensional comparative proteomics analysis of rat hearts perfused with glucose at high (30 mM) or control (5.5 mM) levels revealed that glucose loading alters cardiomyocyte proteomes. It increased expression levels of initial enzymes of the tricarboxylic acid cycle, and of enzymes of fatty acid beta-oxidation, with consequent up-regulation of enzymes of mitochondrial electron transport. It also markedly decreased expression of enzymes of glycolysis and the final steps of the tricarboxylic acid cycle. Glucose loading increased the rate of Bax-independent apoptosis. High glucose increased the duration of the action potential and elevated level of intracellular cytoplasmic calcium. Surprisingly, glucose loading did not influence levels of nitric oxide or mitochondrial superoxide in isolated cardiomyocytes. In summary, short-term simulated hyperglycemia attenuated expression of many anti-apoptotic proteins. This effect was apparently mediated via alterations in multiple biochemical pathways that collectively increased apoptotic susceptibility.

Effects of exercise and oral antioxidant supplementation enriched in (n−3) fatty acids on blood oxidant markers and erythrocyte membrane fluidity in horses

The aim of this study was to investigate in a placebo-controlled field study the effect of a (n-3)-vitamin supplementation on erythrocyte membrane fluidity (EMF), oxidant/antioxidant markers and plasmatic omega3/omega6 fatty acid ratio (FAR) in 12 eventing horses. Venous blood was sampled at rest before (PRE) and after (POST) a three week treatment period with either the supplement (group S, n=6) or a placebo (group P, n=6) as well as after 15min (POST E15') and 24h (POST E24h) after a standardised exercise test. The following markers were analysed: EMF, plasma antioxidant capacity of water and lipid soluble components, ascorbic acid, uric acid (UA), glutathione (reduced: GSH, oxidised: GSSG), vitamin E (Vit E), beta-carotene, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity, selenium, copper (Cu), zinc (Zn), oxidised proteins (Protox), lipid peroxides (Pool) and FAR. EMF did not differ between group S and P after treatment, but GPx remained unchanged in group S whereas it decreased in group P and plasma Cu/Zn ratio remained unchanged whereas it increased in group P. FAR were significantly increased in group S. Exercise induced a significant decrease of EMF (POST vs. E24h) in both groups, but which was significantly lower at E15' in group S than in group P. Exercise induced a significant increase of UA and ACW (POST vs. E15') and Protox (POST vs. E24h) in both groups. An exercise-related decrease in GSH and Pool (POST vs. E15') was found in group P, whereas Vit E and FAR (POST vs. E24h) significantly decreased in both groups. The study showed that exercise induced a decrease in EMF in horses associated with changes of blood oxidative balance. The (omega-3)-vitamin supplementation tested improved the oxidative balance poorly but delayed the exercise-induced decrease of EMF and increased the FAR.

Phase 2 enzyme induction by conjugated linoleic acid improves lupus-associated oxidative stress

Conjugated linoleic acid (CLA) exhibits anticancer and anti-inflammatory properties. Its ability to increase total GSH (GSH+GSSG) amount and gamma-glutamylcysteine ligase (gammaGCL) protein expression was recently associated with the inhibition of typical pathological signs in MRL/MpJ-Fas(lpr) mice (MRL/lpr). In the present study the ability of CLA to modulate oxidative stress and phase 2 enzyme activity in the same animal model was investigated. Disease severity was associated with age-dependent production of anti-double-stranded DNA antibodies (anti-dsDNA IgGs) and with enhanced extent of oxidative stress markers: reduced total GSH, increased protein 3-nitrotyrosines (3-NT), and protein-bound carbonyl (PC) amounts. To examine the effect of CLA on antioxidant status, CLA or olive oil (as control) was administered to pregnant MRL/lpr mice. Significantly higher total GSH and Trolox equivalent antioxidant capacity (TEAC) levels were measured in serum of CLA-treated dams (and their pups), as compared with controls. Finally, the antioxidant and chemopreventive properties of CLA were investigated in old MRL/lpr mice. Sera of CLA-treated mice contained higher concentrations of total GSH which were negatively correlated with the levels of oxidative stress markers. Moreover, increased GSH, gammaGCL, glutathione S-transferase (GSTs), and NAD(P)H:quinone oxidoreductase (NQO1) activities were measured in liver and spleen of CLA-treated animals. In conclusion our data indicate that the activation of detoxifying enzymes may be one of the mechanisms whereby dietary CLA down-regulates oxidative stress in MRL/lpr mice.

Phospholipid hydroperoxide glutathione peroxidase plays a role in protecting cancer cells from docosahexaenoic acid-induced cytotoxicity

Docosahexaenoic acid (DHA; 22:6, n-3) is known to exert cytotoxic effects against various types of tumors via lipid peroxidation. Whereas several enzymes influence the response of cells to oxidative stress, only one enzyme, phospholipid hydroperoxide glutathione peroxidase (GPx-4), directly reduces lipid hydroperoxides in mammalian cells. The present study was designed to examine the involvement of GPx-4 in determining the effects of DHA addition to various human cancer cell lines. Although baseline levels of GPx-4 did not correlate with the relative sensitivity of human cancer cell lines to DHA, DHA reduced the level of protein expression of GPx-4 by at least 50% in all six lines. Knockdown of GPx-4 by small interfering RNA technique in a human ovarian cancer cell line significantly enhanced the cytotoxic effect of DHA in a time- and concentration-dependent manner. This cytotoxic effect of DHA was reversed by pretreatment with vitamin E, suggesting that the enhanced toxicity of GPx-4 knockdown is due to changes in the ability of the cells to handle oxidative stress. Neither baseline superoxide dismutase-1 nor catalase expression correlated with the relative sensitivity of the cells to DHA treatment. These results illustrate that susceptibility to the oxidative stress imposed by DHA, and possibly other therapeutic agents, is due to complex interactions among multiple antioxidant systems. The modulation of GPx-4 levels by DHA administration is of potential importance and may influence the cellular response to other oxidant stresses.

Effects of dietary fats (fish, olive and high-oleic-acid sunflower oils) on lipid composition and antioxidant enzymes in rat liver

The effects of two oleic-acid-rich diets (containing olive oil, OO, and high-oleic-acid sunflower oil, HOSO) on plasma and liver lipid composition detoxification enzyme activities, were compared with those of a fish-oil (FO) diet and a control diet. Compared with the control diet, plasma and hepatic total triacylglycerol concentrations were increased in the animals fed on the HOSO and OO diets and decreased in those fed on the FO diet. The animals fed on FO showed the highest level of cholesterol in the liver and had lower plasma cholesterol concentrations when compared with those fed on the two oleic-acid-rich diets. In comparison with the animals fed on the diets enriched in oleic acid, the FO group showed higher hepatic levels of polyunsaturated fatty acids of then-3 series and lower levels of fatty acids of then-6 series. Livers of FO-fed rats, compared with those of OO- and HOSO-fed rats showed: (1) significantly higher activities of catalase (EC1.11.1.6) glutathione peroxidase (EC1.11.1.9) and Cu/Zn superoxide dismutase (EC1.15.1.1); (2) no differences in the NADPH-cytochromecreductase (EC1.6.99.3) activity. The HOSO diet had a similar effect on liver antioxidant enzyme activities as the OO diet. In conclusion, it appears that changes in the liver fatty acid composition due mainly ton-3 lipids may enhance the efficiency of the antioxidant defence system. The two monounsaturated fatty acids oils studied (OO and HOSO), with the same high content of oleic acid but different contents of natural antioxidants, had similar effects on the antioxidant enzyme activities measured.

Conjugated linoleic acid enhances glutathione synthesis and attenuates pathological signs in MRL/MpJ-Fas(lpr) mice

Conjugated linoleic acid (CLA), a naturally occurring peroxisome proliferator-activated receptor gamma (PPAR gamma) ligand, exhibits proapoptotic, immunomodulatory, and anticancer properties. In this study, we examined the biological effects of CLA administration in the MRL/MpJ-Fas(lpr) mouse, an animal model of systemic lupus erythematosus (SLE). We found that CLA exerted apparently opposed activities in in vitro experiments, depending on its concentration: 100 microM CLA downregulated IFN gamma synthesis and cell proliferation of splenocytes, in association with apoptosis induction and a decrease of intracellular thiols (GSH + GSSG), whereas 25 microM CLA did not significantly influence cell proliferation but enhanced the expression of gamma-glutamylcysteine ligase catalytic subunit (GCLC) and intracellular GSH concentration. Interestingly, the antiproliferative effect at 100 microM was not inhibited by the PPAR gamma antagonist GW9662. In vivo, CLA administration drastically reduced SLE signs (splenomegaly, autoantibodies, and cytokine synthesis), a condition paralleled by the enhancement of GCLC expression and intracellular GSH content. Moreover, CLA administration significantly downregulated nuclear factor kappaB activity independent of PPAR gamma activation and apoptosis induction. In conclusion, enhanced GSH content and GCLC expression in CLA-treated mice suggest a novel biochemical mechanism underlying its immunomodulatory activity and the beneficial effects on murine SLE signs.

Inhibition of inflammatory response in transgenic fat-1 mice on a calorie-restricted diet

Both n-3 fatty acids (n-3 FA) and calorie-restriction (CR) exert anti-inflammatory effects in animal models of autoimmunity and inflammation. In the present study we investigated the synergistic anti-inflammatory effects of n-3 FA and CR on LPS-mediated inflammatory responses using fat-1 transgenic mice that generate n-3 FA endogenously. Wild-type (WT) and fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) diet for 5 mo; splenocytes were cultured in vitro with/without LPS. Our results show: (i) no difference in body weights between WT and fat-1 mice on AL or CR diets, (ii) lower n-6/n-3 FA ratio in splenocytes from fat-1 mice on both AL and CR diets, (iii) significant reduction in NF-kappaB (p65/p50) and AP-1 (c-Fos/c-Jun) DNA-binding activities in splenocytes from fat-1/CR mice following LPS treatment, and (iv) significant reduction in kappaB- and AP-1-responsive IL-6 and TNF-alpha secretion following LPS treatment in splenocytes from fat-1/CR mice. The inhibition of LPS-mediated effects was more pronounced in fat-1/CR mice when compared to fat-1/AL or WT/CR mice. These data show that transgenic expression of fat-1 results in decreased pro-inflammatory n-6 FA, and demonstrate for the first time that splenocytes from fat-1 mice on CR diet exhibit reduced pro-inflammatory response when challenged with LPS. These results suggest that n-3 lipids with moderate CR may confer protection in autoimmune and inflammatory diseases.

Antioxidant enzyme activities and lipid peroxidation induced by eicosapentaenoic acid (EPA) in PC12 cells

Eicosapentaenoic acid (EPA) is one of the major dietary polyunsaturated fatty acids and induces apoptosis in several cancer cells. In this study, the EPA induced lipid peroxidation and response of antioxidative enzymes have been investigated in rat pheochromocytoma PC12 cells to elucidate the mechanisms of apoptosis induced by the polyunsaturated fatty acid EPA. We have analyzed superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and glutathione (GSH) contents in PC12 cells after exposure to different concentrations of EPA. Lipid peroxidation was shown to increase in the presence of EPA as an indication of the oxidative damage. Lipid peroxidation was enhanced by EPA in a dose-dependent manner, and the loss of cell viability was partially reversed by vitamin E. In the case of antioxidant enzyme activities, SOD and GPX activities and GSH contents increased significantly at 50 micromol/L EPA and were respectively 2.41-fold (p < 0.01), 3.49-fold (p < 0.05), and 1.43-fold (p < 0.05) higher than controls. The CAT activity at 10 micromol/L had the highest value and was increased by 25.83% (p < 0.05) compared to control. The results suggest that in PC12 cells the mechanism of apoptosis induced by EPA may be partly due to lipid peroxidation.

Dietary fish oil alters cardiomyocyte Ca2+ dynamics and antioxidant status

The n-3 polyunsaturated fatty acids (PUFAs) found in fish oil (FO) have been shown to protect against reperfusion arrhythmias, a manifestation of reperfusion injury, which is believed to be induced by the formation of reactive oxygen species (ROS) and intracellular calcium (Ca2+) overload. Adult rats fed a diet supplemented with 10% FO had a higher proportion of myocardial n-3 PUFAs and increased expression of antioxidant enzymes compared with the saturated fat (SF)-supplemented group. Addition of hydrogen peroxide (H2O2) to cardiomyocytes isolated from rats in the SF-supplemented group increased the proportions of cardiomyocytes contracting in an asynchronous manner, increased the rate of Ca2+ influx, and increased the diastolic and systolic [Ca2+]i compared with the FO group. H2O2 exposure increased the membrane fluidity of cardiomyocytes from the FO group. These results demonstrate that dietary FO supplementation is associated with a reduction in the susceptibility of myocytes to ROS-induced injury and this may be related to membrane incorporation of n-3 PUFAs, increased antioxidant defenses, changes in cardiomyocyte membrane fluidity, and the ability to prevent rises in cellular Ca2+ in response to ROS.