Ω3-Polyunsaturated fatty acids prevent lipoperoxidation, modulate antioxidant enzymes, and reduce lipid content but do not alter glycogen metabolism in the livers of diabetic rats fed on a high fat thermolyzed diet

Evaluation of the effects of dietary advanced glycation end products on inflammation

Advanced glycation end products (AGEs) are a large number of heterogeneous compounds formed by the glycation of proteins, fats or nucleic acids. Endogenous AGEs have been associated with various health problems such as obesity, type 2 diabetes mellitus and cardiovascular disease. Inflammation is thought to be one of the main mechanisms in the development of these disorders. Although AGEs are produced endogenously in the body, exogenous sources such as smoking and diet also contribute to the body pool. Therefore, when the AGE pool in the body rises above physiological levels, different pathological conditions may occur through various mechanisms, especially inflammation. While the effects of endogenous AGEs on the development of inflammation have been studied relatively extensively, and current evidence indicates that dietary AGEs (dAGEs) contribute to the body's AGE pool, it is not yet known whether dAGEs have the same effect on the development of inflammation as endogenous AGEs. Therefore, this review aimed to evaluate the results of cross-sectional and intervention studies to understand whether dAGEs are associated with inflammation and, if there is an effect on inflammation, through which mechanisms this effect might occur.

Omega-3 polyunsaturated fatty acid biomarkers and risk of type 2 diabetes, cardiovascular disease, cancer, and mortality

BACKGROUND & AIMS

Considerable attention has focused on the role of omega-3 polyunsaturated fatty acids (PUFA) in the prevention of cardiometabolic diseases, which has led to dietary recommendations to increase omega-3 fatty acid intake. A meta-analysis was conducted to summarize evidence from prospective studies regarding associations between omega-3 PUFA biomarkers and risk of developing major chronic diseases.

METHODS

Four electronic databases were searched for articles from inception to March 1, 2022. Random-effects model was used to estimate the pooled relative risk (RR) and 95% confidence intervals (CIs) for the association of omega-3 PUFAs, including α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), with risk of developing type 2 diabetes (T2D), cardiovascular disease (CVD), including coronary heart disease (CHD) and stroke, cancer, and mortality. The Grades of Recommendation, Assessment, Development and Evaluation assessment tool was used to rates the confidence in estimates.

RESULTS

A total of 67 prospective studies comprised of 310,955 participants were identified. Individual omega-3 PUFAs showed divergent associations with the study outcomes of interest. A significant inverse association with T2D risk was observed across categories of ALA (relative risk [RR]: 0.89, 95% confidence interval [CI]: 0.82-0.96), EPA (RR: 0.85, 95% CI: 0.72-0.99) and DPA (RR: 0.84, 95% CI: 0.73-0.96) biomarkers. The marine-origin omega-3 fatty acids biomarkers but not ALA was significantly associated with lower risks of total CVD, CHD, and overall mortality, with RRs ranging from 0.70 for DHA-CHD association to 0.85 for EPA-CHD association. A lower risk of colorectal cancer was observed at higher levels of DPA (RR: 0.76, 95% CI: 0.59-0.98) and DHA (RR: 0.80; 95% CI: 0.65-0.99), whereas no association was noted for other outcomes. In addition, a dose-response relationship was observed between an increasing level of EPA, DPA, or DHA biomarker and lower risk of CVD.

CONCLUSIONS

Higher concentrations of marine-derived omega-3 PUFA biomarkers were associated with a significantly reduced risk of total CVD, CHD, and total mortality. Levels of ALA were inversely associated with a lower risk of T2D but not CVD-related outcomes. These data support the dietary recommendations advocating the role of omega-3 PUFAs in maintaining an overall lower risk of developing cardiovascular disease and premature deaths.

Functional Meat Products as Oxidative Stress Modulators: A Review

High meat consumption has been associated with increased oxidative stress mainly due to the generation of oxidized compounds in the body, such as malondialdehyde, 4-hydroxy-nonenal, oxysterols, or protein carbonyls, which can induce oxidative damage. Meat products are excellent matrices for introducing different bioactive compounds, to obtain functional meat products aimed at minimizing the pro-oxidant effects associated with high meat consumption. Therefore, this review aims to summarize the concept and preparation of healthy and functional meat, which could benefit antioxidant status. Likewise, the key strategies regarding meat production and storage as well as ingredients used (e.g., minerals, polyphenols, fatty acids, walnuts) for developing these functional meats are detailed. Although most effort has been made to reduce the oxidation status of meat, newly emerging approaches also aim to improve the oxidation status of consumers of meat products. Thus, we will delve into the relation between functional meats and their health effects on consumers. In this review, animal trials and intervention studies are discussed, ascertaining the extent of functional meat products' properties (e.g., neutralizing reactive oxygen species formation and increasing the antioxidant response). The effects of functional meat products in the frame of diet-gene interactions are analyzed to 1) discover target subjects that would benefit from their consumption, and 2) understand the molecular mechanisms that ensure precision in the prevention and treatment of diseases, where high oxidative stress takes place. Long-term intervention-controlled studies, testing different types and amounts of functional meat, are also necessary to ascertain their positive impact on degenerative diseases.

Effect of Chlorella vulgaris on Liver Function Biomarkers: a Systematic Review and Meta-Analysis

This study presents a comprehensive systematic review and meta-analysis of randomized controlled trials (RCTs) on Chlorella vulgaris (C. vulgaris) supplementation and liver function biomarkers. Pertinent studies were identified using Scopus, ISI Web of Science, PubMed, and Cochrane library databases up to August 2020. Mean differences were pooled using a random-effects model. Pooling 7 RCTs together showed that C. vulgaris supplementation led to a significant reduction of serum aspartate aminotransferase (AST) levels (weighted mean difference [WMD], −9.15 U/L; 95% confidence interval [CI], −16.09, −2.21), but not alanine aminotransferase (ALT) or alkaline phosphatase (ALP) levels compared to the placebo consumption. Subgroup-analysis indicated that C. vulgaris supplementation had more effect on AST decreasing among non-alcoholic fatty liver disease patients (WMD, −16.42 U/L; 95% CI, −29.75, −3.09) than others. Furthermore, subgroup analysis based on kind of compression showed that C. vulgaris supplementation significantly decreased ALT levels (WMD, −4.65 U/L; 95% CI, −8.88, −0.42) compared with the placebo, but not metformin consumption. It seems that C. vulgaris supplementation mainly affects AST levels rather than ALT and ALP levels, however, as mentioned the effect of C. vulgaris on those enzymes might be context-dependent. Therefore, further investigations with a large number of patients as well as on different disorders are necessary and can provide more definitive evidence.

Dietary fish oil supplement induces age-specific contractile and proteomic responses in muscles of male rats

Background

Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated.

Methods

This preliminary study evaluated 14 adult (8 months) and 12 aged (22 months) male, Sprague-Dawley rats consuming a DFO-supplemented diet or a control diet for 8 weeks (7 adult and 6 aged/dietary group). Animal weight, food intake and grip strength were assessed at the start and end of the FO intervention. In situ force and contractile properties were measured in the medial gastrocnemius muscle following the intervention and muscles were processed for 2-D gel electrophoresis and proteomic analysis via liquid chromatography with tandem mass spectrometry, confirmed by immunoblotting. Effects of age, diet and age x diet interaction were evaluated by 2-way ANOVA.

Results

A significant (P = 0.022) main effect for DFO to increase (~ 15%) muscle contractile force was observed, without changes in muscle mass. Proteomic analysis revealed a small number of proteins that differed across age and dietary groups at least 2-fold, most of which related to metabolism and oxidative stress. In seven of these proteins (creatine kinase, triosephosphate isomerase, pyruvate kinase, parvalbumin, beta-enolase, NADH dehydrogenase and Parkin7/DJ1), immunoblotting corroborated these findings. Parvalbumin showed only an effect of diet (increased with DFO) (P = 0.003). Significant age x diet interactions were observed in the other proteins, generally demonstrating increased expression in adult and decreased expression aged rats consuming DFO (all P > 0.011). However, correlational analyses revealed no significant associations between contractile parameters and protein abundances.

Conclusions

Results of this preliminary study support the hypothesis that DFO can enhance musculoskeletal health in adult and aged muscles, given the observed improvement in contractile function. The fish oil supplement also alters protein expression in an age-specific manner, but the relationship between proteomic and contractile responses remains unclear. Further investigation to better understand the magnitude and mechanisms muscular effects of DFO in aged populations is warranted.

Omega-3 polyunsaturated fatty acids have beneficial effects on visceral fat in diet-induced obesity model

This study evaluated the effects of omega-3 polyunsaturated fatty acids (PUFAs) on oxidative stress and energy metabolism parameters in the visceral fat of a high-fat-diet induced obesity model. Energy intake, body mass, and visceral fat mass were also evaluated. Male Swiss mice received either a control diet (control group) or a high-fat diet (obese group) for 6 weeks. After this period, the groups were divided into control + saline, control + omega-3, obese + saline, and obese + omega-3, and to these groups 400 mg·(kg body mass)-1·day-1 of fish oil (or saline) was administered orally, for 4 weeks. Energy intake and body mass were monitored throughout the experiment. In the 10th week, the animals were euthanized and the visceral fat (mesenteric) was removed. Treatment with omega-3 PUFAs did not affect energy intake or body mass, but it did reduced visceral fat mass. In visceral fat, omega-3 PUFAs reduced oxidative damage and alleviated changes to the antioxidant defense system and the Krebs cycle. The mitochondrial respiratory chain was neither altered by obesity nor by omega-3 PUFAs. In conclusion, omega-3 PUFAs have beneficial effects on the visceral fat of obese mice because they mitigate changes caused by the consumption of a high-fat diet.

Dietary Glycotoxins Impair Hepatic Lipidemic Profile in Diet-Induced Obese Rats Causing Hepatic Oxidative Stress and Insulin Resistance

Nonalcoholic fatty liver disease (NAFLD) is caused by excessive liver lipid accumulation, but insulin resistance is specifically associated with impaired lipid saturation, oxidation, and storage (esterification), besides increased de novo lipogenesis. We hypothesized that dietary glycotoxins could impair hepatic lipid metabolism in obesity contributing to lipotoxicity-driven insulin resistance and thus to the onset of nonalcoholic steatohepatitis (NASH). In diet-induced obese rats with methylglyoxal-induced glycation, magnetic resonance spectroscopy, mass spectrometry, and gas chromatography were used to assess liver composition in fatty acyl chains and phospholipids. High-fat diet-induced obesity increased liver lipid fraction and suppressed de novo lipogenesis but did not change fatty acid esterification and saturation or insulin sensitivity. Despite a similar increase in total lipid fraction when supplementing the high-fat diet with dietary glycotoxins, impairment in the suppression of de novo lipogenesis and decreased fatty acid unsaturation and esterification were observed. Moreover, glycotoxins also decreased polyunsaturated cardiolipins and caused oxidative stress, portal inflammation, and insulin resistance in high-fat diet-induced obese rats. Dietary glycated products do not change total lipid levels in the liver of obese rats but dramatically modify the lipidemic profile, leading to oxidative stress, hepatic lipotoxicity, and insulin resistance in obesity and thus contribute to the onset of NASH.

Weight loss enhances hepatic antioxidant status in a NAFLD model induced by high-fat diet

Nonalcoholic fatty liver disease (NAFLD) is a benign condition that can progress to more severe liver damage in a process mediated, in part, by disturbances in redox balance. Additionally, some argue that it is set to become the main cause of end-stage liver disease in the near future. Here, we investigated whether diet-induced weight loss is able to reverse hepatic lipid accumulation and reduce oxidative stress in liver from C57BL/6 mice fed a high-fat (HF) diet. Male C57BL/6 mice were divided into 4 groups: standard chow (SC; 10% energy from fat, 16 weeks); HF (50% energy from fat, 16 weeks); SC-HF (SC for 8 weeks followed by HF for 8 weeks); and HF-SC (HF for 8 weeks followed by SC for 8 weeks). The HF diet during 8 (SC-HF) and 16 weeks (HF) downregulated messenger RNA levels and protein expression of Nrf2 and endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) in the liver; caused liver steatosis; affected liver function markers; increased intra-abdominal and subcutaneous adipose tissue; and induced glucose intolerance and hypercholesterolemia compared with controls (SC). Diet-induced weight loss significantly reduced the intrahepatic lipid accumulation, improved glucose tolerance, and restored both gene and protein expression of the antioxidant enzymes. Our findings suggest that a dietary intervention aimed to induce weight loss may exert protective effects in NAFLD as it can reduce hepatic oxidative stress and intrahepatic lipid accumulation, which can hinder the progression of this condition to more severe states.

Cerebral Ketone Body Oxidation Is Facilitated by a High Fat Diet Enriched with Advanced Glycation End Products in Normal and Diabetic Rats

Diabetes mellitus (DM) causes important modifications in the availability and use of different energy substrates in various organs and tissues. Similarly, dietary manipulations such as high fat diets also affect systemic energy metabolism. However, how the brain adapts to these situations remains unclear. To investigate these issues, control and alloxan-induced type I diabetic rats were fed either a standard or a high fat diet enriched with advanced glycation end products (AGEs) (HAGE diet). The HAGE diet increased their levels of blood ketone bodies, and this effect was exacerbated by DM induction. To determine the effects of diet and/or DM induction on key cerebral bioenergetic parameters, both ketone bodies (β-hydroxybutyric acid) and lactate oxidation were measured. In parallel, the expression of Monocarboxylate Transporter 1 (MCT1) and 2 (MCT2) isoforms in hippocampal and cortical slices from rats submitted to these diets was assessed. Ketone body oxidation increased while lactate oxidation decreased in hippocampal and cortical slices in both control and diabetic rats fed a HAGE diet. In parallel, the expression of both MCT1 and MCT2 increased only in the cerebral cortex in diabetic rats fed a HAGE diet. These results suggest a shift in the preferential cerebral energy substrate utilization in favor of ketone bodies in animals fed a HAGE diet, an effect that, in DM animals, is accompanied by the enhanced expression of the related transporters.

Therapeutic effect of flax-based diets on fatty liver in aged laying hens

This study examined the ability of flax-based ingredients to attenuate nonalcoholic fatty liver disease ( NAFLD: ) in aged laying hens-a novel and more physiologically relevant model of human disease. Our results showed only hens supplemented with whole flaxseed ( WFX: ) reduced steatosis and hepatocellular ballooning. Serum AST was also reduced in hens provided WFX and defatted flaxseed meal ( DFM: ). Hepatic ω-3 PUFA enrichment was improved with supplementation of WFX, DFM, and flaxseed oil ( FXO: ). However, this effect was more evident in the WFX group. In contrast, transcript abundance of genes linked to NAFLD were predominantly modified with FXO supplementation. Taken together, our data indicate a potential synergistic relationship between the fatty acid and lignan content in flaxseed which attenuated the progression of NAFLD in aged laying hens. Although more research is necessary, these findings demonstrate the potential use of whole flaxseed for the treatment and prevention of NAFLD in humans.

Decreased n-6/n-3 polyunsaturated fatty acid ratio reduces chronic reflux esophagitis in rats

AIM

To investigate the effect of dietary ratio of n-6/n-3 PUFAs on chronic reflux esophagitis (RE) and lipid peroxidation.

METHOD

Rat RE model were established and then fed on a diet contained different n-6/n-3 PUFA ratios (1:1.5, 5:1, 10:1) or received pure n-6 PUFA diet for 14 days. Esophageal pathological changes were evaluated using macroscopic examination and hematoxyline-eosin staining. IL-1β, IL-8, and TNFα mRNA and protein levels of were determined using RT-PCR and Western blotting, respectively. Malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined using ELISA.

RESULTS

The severity of esophagitis was lowest in the PUFA(1:1.5) group (P<0.05). IL-1β, IL-8, and TNFα mRNA and protein and MDA levels were significantly increased in model groups with the increasing n-6/n-3 PUFA ratios. SOD levels were significantly decreased in all RE PUFA groups (P<0.05).

CONCLUSION

Esophageal injury and lipid peroxidation appeared to be ameliorated by increased n-3 PUFAs intake.

Hyperglycemia-associated alterations in cellular signaling and dysregulated mitochondrial bioenergetics in human metabolic disorders

Purpose

The severity of untreated or refractory diabetes mellitus has been functionally linked to elevated concentrations of free plasma glucose, clinically defined as hyperglycemia. Operationally, the pathophysiological presentations of prolonged hyperglycemia may be categorized within insulin-dependent and insulin-independent, type 1 and type 2 diabetic phenotypes, respectively. Accordingly, major areas of empirical biomedical research have focused on the elucidation of underlying mechanisms driving key cellular signaling systems that are significantly altered in patients presenting with diabetes-associated chronic hyperglycemia.

Methods

Presently, we provide a translationally oriented review of key studies evaluating the aberrant effects of hyperglycemia on two major signaling pathways linked to debilitating cellular and systemic effects via targeted disruption of mitochondrial bioenergetics: (1) advanced glycation end-products (AGEs)/and their cognate receptor for advanced glycation end-products (RAGEs), and (2) the hexosamine biosynthetic pathway (HBP).

Results

In preclinical models, cultured vascular endothelial cells exposed to hyperglycemic glucose concentrations were observed to produce enhanced levels of reactive oxygen species (ROS) functionally linked to increased formation of AGEs and expression of their cognate RAGEs. Importantly, inhibitors of AGEs formation, mitochondrial complex II, or un-couplers of oxidative phosphorylation, were observed to significantly reduce the effects of hyperglycemia on ROS production and cellular damage, thereby establishing a critical linkage to multiple levels of mitochondrial functioning. Hyperglycemia-mediated enhancement of mitochondrial ROS/superoxide production in vascular endothelial cells has been functionally linked to the shunting of glucose into the HBP with resultant long-term activation of pro-inflammatory signaling processes. Additionally, exposure of cultured cells to hyperglycemic conditions resulted in enhanced HBP-mediated inhibition of protein subunits of mitochondrial respiratory complexes I, III, and IV, intimately associated with normative cellular bioenergetics and ATP production.

Conclusions

Convergent lines of evidence link chronic hyperglycemic conditions to aberrant expression of AGEs/RAGEs and HBP signaling pathways in relation to the pathophysiological formation of ROS and pro-inflammatory processes on the functional dysregulation of mitochondrial bioenergetics.

Effect of a trans fatty acid-enriched diet on biochemical and inflammatory parameters in Wistar rats

PURPOSE

Recent data regarding trans fatty acids (TFAs) have implicated these lipids as particularly deleterious to human health, causing systemic inflammation, endothelial dysfunction and possibly inflammation in the central nervous system (CNS). We aimed to clarify the impact of partially hydrogenated soybean oil (PHSO) with different TFA concentrations on cerebrospinal fluid (CSF), serum and hepatic parameters in adult Wistar rats.

METHODS

Wistar rats (n = 15/group) were fed either a normolipidic diet or a hyperlipidic diet for 90 days. The normolipidic and hyperlipidic diets had the same ingredients except for fat compositions, concentrations and calories. We used lard in the cis fatty acid group and PHSO in the trans fatty acid group. The intervention groups were as follows: (1) low lard (LL), (2) high lard (HL), (3) low partially hydrogenated soybean oil (LPHSO) and (4) high partially hydrogenated soybean oil (HPHSO). Body weight, lipid profiles and the inflammatory responses in the CSF, serum and liver tissue were analyzed.

RESULTS

Surprisingly, with the PHSO diet we observed a worse metabolic response that was associated with oxidative stress in hepatic tissue as well as impaired serum and CSF fluid parameters at both PHSO concentrations. In many analyses, there were no significant differences between the LPHSO and HPHSO diets.

CONCLUSIONS

Dietary supplementation with PHSO impaired inflammatory parameters in CSF and blood, induced insulin resistance, altered lipid profiles and caused hepatic damage. Overall, these findings suggest that fat composition is more important than the quantity of fat consumed in terms of cis and trans fatty acid diets.

The Role of Oxidative Stress and Antioxidants in Liver Diseases

A complex antioxidant system has been developed in mammals to relieve oxidative stress. However, excessive reactive species derived from oxygen and nitrogen may still lead to oxidative damage to tissue and organs. Oxidative stress has been considered as a conjoint pathological mechanism, and it contributes to initiation and progression of liver injury. A lot of risk factors, including alcohol, drugs, environmental pollutants and irradiation, may induce oxidative stress in liver, which in turn results in severe liver diseases, such as alcoholic liver disease and non-alcoholic steatohepatitis. Application of antioxidants signifies a rational curative strategy to prevent and cure liver diseases involving oxidative stress. Although conclusions drawn from clinical studies remain uncertain, animal studies have revealed the promising in vivo therapeutic effect of antioxidants on liver diseases. Natural antioxidants contained in edible or medicinal plants often possess strong antioxidant and free radical scavenging abilities as well as anti-inflammatory action, which are also supposed to be the basis of other bioactivities and health benefits. In this review, PubMed was extensively searched for literature research. The keywords for searching oxidative stress were free radicals, reactive oxygen, nitrogen species, anti-oxidative therapy, Chinese medicines, natural products, antioxidants and liver diseases. The literature, including ours, with studies on oxidative stress and anti-oxidative therapy in liver diseases were the focus. Various factors that cause oxidative stress in liver and effects of antioxidants in the prevention and treatment of liver diseases were summarized, questioned, and discussed.

Effect of diet-derived advanced glycation end products on inflammation

Advanced glycation end products (AGEs) formed via the Maillard reaction during the thermal processing of food contributes to the flavor, color, and aroma of food. A proportion of food-derived AGEs and their precursors is intestinally absorbed and accumulates within cells and tissues. AGEs have been implicated in the pathogenesis of diabetes-related complications and several chronic diseases via interaction with the receptor for AGEs, which promotes the transcription of genes that control inflammation. The dicarbonyls, highly reactive intermediates of AGE formation, are also generated during food processing and may incite inflammatory responses through 1) the suppression of protective pathways, 2) the incretin axis, 3) the modulation of immune-mediated signaling, and 4) changes in gut microbiota profile and metabolite sensors. In animal models, restriction of dietary AGEs attenuates chronic low-grade inflammation, but current evidence from human studies is less clear. Here, the emerging relationship between excess dietary AGE consumption and inflammation is explored, the utility of dietary AGE restriction as a therapeutic strategy for the attenuation of chronic diseases is discussed, and possible avenues for future investigation are suggested.

Dietary Supplementation with Raspberry Seed Oil Modulates Liver Functions, Inflammatory State, and Lipid Metabolism in Rats

BACKGROUND

Although raspberry seed oil (RO) is rich in essential fatty acids, there is a lack of experiments assessing benefits of its consumption.

OBJECTIVE

We investigated the effects of dietary supplementation with RO on healthy rats and rats with low-grade systemic inflammation, liver disorders, and dyslipidemia induced by a high-fat/low-fiber (HF/LF) diet.

METHODS

Thirty-two rats were allocated into 4 groups of 8 rats each and fed for 8 wk a control (C; 7% lard and 5% cellulose) or HF/LF (21% lard and 2% cellulose) diet or modifications of these diets in which 7% RO replaced all (C+RO group) or a proportion of (HF/LF+RO group) the lard. Effects of diet and RO and their interaction on bacterial activity and metabolite formations in the distal intestine, liver fat and glutathione concentration, plasma lipid profile, transaminase activities, and plasma concentrations of C-reactive protein (CRP) and tumor necrosis factor α (TNF-α) were tested.

RESULTS

Dietary RO decreased plasma alanine and aspartate transaminase activities (43.4 and 157 vs. 25.6 and 115 U/L, respectively; P < 0.05 and P < 0.005) and plasma TNF-α and triglyceride concentrations (132 pg/mL and 2.07 mmol/L vs. 86.5 pg/mL and 0.99 mmol/L, respectively; P < 0.05). In livers of the C+RO group, the fat concentration was decreased, whereas the glutathione to glutathione disulfide ratio was increased compared with the C group (30.1% and 6.20 μmol/g vs. 23.3% and 7.25 μmol/g, respectively; P ≤ 0.05); however, those differences were not observed between the HF/LF groups (P-interaction < 0.05). In the HF/LF+RO group, the plasma CRP concentration was lower than in the HF/LF group (88.1 vs. 765 pg/mL; P ≤ 0.05) and similar to that in the C and C+RO groups (158 and 128 pg/mL, respectively).

CONCLUSION

Dietary RO improves plasma lipid profile and liver functions and reduces low-grade systemic inflammation in rats; however, the extent of these beneficial effects is partly dependent on the diet type.

Lipid peroxidation and antioxidant protection in girls with type 1 diabetes mellitus during reproductive system development

BACKGROUND AND OBJECTIVE

Type 1 diabetes mellitus (T1D) is found worldwide and is regarded as one of the main risks to human health. The objective of this study was to determine the state of lipid peroxidation (LPO) and antioxidant protection in girls with T1D type considering the stages of reproductive system development.

MATERIALS AND METHODS

This study enrolled 56 young girls with T1D and 60 healthy girls (control) matched by age. The study population was divided into 3 age groups: prepubertal, adolescent, and juvenile. The state of LPO and antioxidant system was assessed using the coefficient of oxidative stress that represented the ratio of LPO products to general antioxidative blood activity. Spectrophotometric and fluorometric methods were applied.

RESULTS

The results of our study showed increased conjugated diene (CD) and thiobarbituric acid reactant (TBAR) concentrations as well as a decreased reduced glutathione level in prepubertal girls with T1D. Adolescent girls with T1D had a significantly greater CD level and juvenile girls with T1D had a significantly greater TBAR level and lower α-tocopherol concentration than girls in the control group. The greatest coefficient of oxidative stress (1.16) was observed in the prepubertal period.

CONCLUSIONS

The prepubertal period is characterized by the most severe state of lipid peroxidation process-antioxidant protection.

Effects of Lactobacillus rhamnosus GG on hepatic and serum lipid profiles in zebrafish exposed to ethanol

Zebrafish is a powerful tool in pharmacological research and useful to identify new therapies. Probiotics can offer therapeutic options in alcoholic liver disease. This study was done in two independent experiments: first, we confirmed the intestinal colonization of probiotic Lactobacillus rhamnosus GG (LGG) after ethanol exposure. Second, four groups were performed: control (C), probiotic (P), ethanol (E), and probiotic+ethanol (P+E). Liver histology, hepatocytes morphometry, hepatic and serum lipid quantifications were conducted in second experiment. During 4 weeks, P and P+E groups were fed with LGG supplemented feed; E and C unsupplemented. E and P+E groups received 0.5% of ethanol added into tank water. Zebrafish exposed to ethanol (E group) presented intense liver steatosis after 28 days in contrast to the almost normalized liver histology of P+E group at the same period. Liver morphometry showed a significant enlargement of hepatocytes of E group after 4 weeks (p<0.0001). Serum triglycerides decreased in P+E group compared with C, P (p<0.001), and E (p=0.004), after 14 and 28 days similarly. Serum cholesterol was also decreased by LGG; P group decreased compared with C and E after 14 days (p=0.002 and p=0.007, respectively) and P+E group decreased significantly compared with E and C groups (p<0.0001) after 28 days. Hepatic triglycerides were reduced in P+E group after 28 days compared to E (p=0.006). The persistence of LGG in zebrafish intestines was demonstrated. LGG decreased serum levels of triglycerides and cholesterol and improved hepatic steatosis.

Preoperative 4-week supplementation with omega-3 polyunsaturated fatty acids reduces liver volume and facilitates bariatric surgery in morbidly obese patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a very common condition among obese patients that may lead to the enlargement of the liver, that in turn impairs the access to the gastro-esophageal junction during laparoscopic bariatric surgery. Omega-3 polyunsaturated fatty acids (Ω-3 PUFAs) supplementation has been shown to reduce nutritional hepatic steatosis. The aim of this study was to assess the effects of a 4-week course of oral Ω-3 PUFAs supplementation on the volume of the liver.

METHODS

20 morbidly obese patients were administered oral Ω-3 PUFAs (1,500 mg daily) for 4 weeks before undergoing the laparoscopic Roux-en-Y gastric bypass (LRYGBP) without any dietary restriction. The volume of the left hepatic lobe was estimated by liver ultrasonography at baseline and at the end of treatment. The degree of difficulty to access the gastro-esophageal junction was appreciated subjectively by the operating surgeon.

RESULTS

All patients completed the study and no side effect was reported. The mean volume of the left hepatic lobe decreased by 20% from 598 ± 97 to 484 ± 118 cm(3) after the treatment (p = 0.002). The access to the gastro-esophageal junction was reported as simple, with easy retraction of the left hepatic lobe by the operating surgeon in all cases.

CONCLUSIONS

This study demonstrates that a 4-week course of oral Ω-3 PUFAs supplementation results in a significant reduction in liver size that facilitates the LRYGBP.

Linoleic and α-linolenic fatty acid consumption over three generations exert cumulative regulation of hepatic expression of genes related to lipid metabolism

The essential fatty acids, omega-3 and omega-6, consumed during pregnancy can benefit maternal and offspring health. For instance, they could activate a network of genes related to the nuclear receptor peroxisome proliferator-activated receptor α (Ppara) and sterol regulatory element binding transcription factor 1 (Srebf1), which play a role in fatty acid oxidation and lipogenesis. The present study aimed to investigate the effects of diets with different omega-3/omega-6 ratio consumed over three generations on blood biochemical parameters and hepatic expression of Ppara- and Srebf1-related genes. During three consecutive generations adult Wistar rats were evaluated in the postpartum period (21 days after parturition). Regardless of prenatal dietary omega-3/omega-6 ratio, an upregulation in liver tissue was observed for Rxra, Lxra and Srebf1 and a downregulation for Fasn in all the evaluated generations. The diet with higher omega-3/omega-6 ratio decreased triacylglycerol serum levels and resulted in a constant non-esterified fatty acid level. Our results indicated that the PUFAs effect on the modulation of genes related to fatty acid oxidation and lipogenesis is cumulative through generations.

Effects of eye drops containing a mixture of omega-3 essential fatty acids and hyaluronic acid on the ocular surface in desiccating stress-induced murine dry eye

PURPOSE

To investigate the efficacy of the topical application of omega-3 essential fatty acids (EFAs) and hyaluronic acid (HA) mixtures in a mouse model of experimental dry eye (EDE).

METHODS

Eye drops consisting of 0.1% HA, 0.02%, or 0.2% omega-3 EFAs alone and mixture of 0.02%, or 0.2% omega-3 EFAs and 0.1% HA were applied in desiccating stress-induced murine dry eye. Corneal irregularity scores and fluorescein staining scores were measured 5 and 10 days after treatment. Levels of interleukin (IL)-1β, -17, and interferon gamma-induced protein (IP)-10 were measured in the conjunctiva at 10 days using a multiplex immunobead assay. The concentrations of hexanoyl-lys (HEL) and 4-hydroxynonenal (4-HNE) in conjunctiva tissue were measured with enzyme-linked immunosorbent assays.

RESULTS

Mice treated with the mixture containing 0.2% omega-3 EFAs showed a significant improvement in corneal irregularity scores and corneal fluorescein staining scores compared with EDE, HA, 0.02% or 0.2% omega-3 EFAs alone, and 0.02% omega-3 EFAs mixture-treated mice. A significant decrease in the levels of IL-1β, -17, and IP-10 were observed in the 0.2% EFAs mixture-treated group, compared with the other groups. In the mice treated with the mixture containing 0.2% omega-3 EFAs, the concentration of 4-HNE was also lower than the other groups. Although 0.2% omega-3 EFAs alone group also had a significant improvement in corneal irregularity scores and IL-17, IL-10, and 4 HNE levels compared with the other groups, the efficacy was lower than 0.2% omega-3 mixture group.

CONCLUSIONS

Topically applied eye drops containing a mixture of omega-3 EFAs and HA could improve corneal irregularity and corneal epithelial barrier disruption, and decrease inflammatory cytokines and oxidative stress markers on the ocular surface. Topical omega-3 EFAs and HA mixture may have a greater therapeutic effect on clinical signs and inflammation of dry eye compared with HA artificial tears.

Novel regulatory roles of omega-3 fatty acids in metabolic pathways: a proteomics approach

Background

Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been shown to alleviate the symptoms of metabolic disorders, such as heart disease, diabetes, obesity and insulin resistance. Several putative mechanisms by which n-3 PUFA elicit beneficial health effects have been proposed; however, there is still a shortage of knowledge on the proteins and pathways that are regulated by n-3 PUFA.

Methods

Using two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, we investigated the effects of diets high or low in n-3 PUFA on hepatic proteomic profile of C57BL/6 mice.

Results

The findings show for the first time that high dietary n-3 PUFA reduced the expression of regucalcin, adenosine kinase and aldehyde dehydrogenase. On the other hand, diets high in n-3 PUFA increased the expression of apolipoprotein A-I, S-adenosylmethionine synthase, fructose-1, 6-bisphosphatase, ketohexokinase, malate dehydrogenase, GTP-specific succinyl CoA synthase, ornithine aminotransferase and protein disulfide isomerase-A3.

Conclusions

Our findings revealed for the first time that n-3 PUFA causes alterations in several novel functional proteins involved in regulating lipid, carbohydrate, one-carbon, citric acid cycle and protein metabolism, suggesting integrated regulation of metabolic pathways. These novel proteins are potential targets to develop therapeutic strategies against metabolic disorders.

Long-chain omega 3 fatty acids: molecular bases of potential antioxidant actions

Several lines of investigation are being developed to assess the impact of polyunsaturated fatty acids, namely those of the omega 3 series, intake on oxidative stress. Keeping in mind that there might be a dose-response relation, in vivo and in vitro data strongly suggest that omega 3 fatty acids might act as anti- rather than pro-oxidant in several cells such as vascular cells, hence diminishing inflammation, oxidative stress, and, in turn, the risk of atherosclerosis and degenerative disorders such as cardiovascular disease.

Coronary endothelial dysfunction and mitochondrial reactive oxygen species in type 2 diabetic mice

Endothelial cell (EC) dysfunction is implicated in cardiovascular diseases, including diabetes. The decrease in nitric oxide (NO) bioavailability is the hallmark of endothelial dysfunction, and it leads to attenuated vascular relaxation and atherosclerosis followed by a decrease in blood flow. In the heart, decreased coronary blood flow is responsible for insufficient oxygen supply to cardiomyocytes and, subsequently, increases the incidence of cardiac ischemia. In this study we investigate whether and how reactive oxygen species (ROS) in mitochondria contribute to coronary endothelial dysfunction in type 2 diabetic (T2D) mice. T2D was induced in mice by a high-fat diet combined with a single injection of low-dose streptozotocin. ACh-induced vascular relaxation was significantly attenuated in coronary arteries (CAs) from T2D mice compared with controls. The pharmacological approach reveals that NO-dependent, but not hyperpolarization- or prostacyclin-dependent, relaxation was decreased in CAs from T2D mice. Attenuated ACh-induced relaxation in CAs from T2D mice was restored toward control level by treatment with mitoTempol (a mitochondria-specific O2(-) scavenger). Coronary ECs isolated from T2D mice exhibited a significant increase in mitochondrial ROS concentration and decrease in SOD2 protein expression compared with coronary ECs isolated from control mice. Furthermore, protein ubiquitination of SOD2 was significantly increased in coronary ECs isolated from T2D mice. These results suggest that augmented SOD2 ubiquitination leads to the increase in mitochondrial ROS concentration in coronary ECs from T2D mice and attenuates coronary vascular relaxation in T2D mice.

Partial rescue of Rett syndrome by ω-3 polyunsaturated fatty acids (PUFAs) oil

Evidence of enhanced oxidative stress (O.S.) and lipid peroxidation has been reported in patients with Rett syndrome (RTT), a relatively rare neurodevelopmental disorder progressing in 4-stages, and mainly caused by loss-of-function mutations in the methyl-CpG-binding protein 2. No effective therapy for preventing or arresting the neurologic regression in the disease in its various clinical presentations is available. Based on our prior evidence of enhanced O.S. and lipid peroxidation in RTT patients, herein we tested the possible therapeutic effects of ω-3 polyunsaturated fatty acids (ω-3 PUFAs), known antioxidants with multiple effects, on the clinical symptoms and O.S. biomarkers in the earliest stage of RTT. A total of 20 patients in stage I were randomized (n = 10 subjects per arm) to either oral supplementation with ω-3 PUFAs-containing fish oil (DHA: 72.9 ± 8.1 mg/kg b.w./day; EPA: 117.1 ± 13.1 mg/kg b.w./day; total ω-3 PUFAs: 246.0 ± 27.5 mg/kg b.w./day) for 6 months or no treatment. Primary outcomes were potential changes in clinical symptoms, with secondary outcomes including variations for five O.S. markers in plasma and/or erythrocytes (nonprotein bound iron, F(2)-dihomo-isoprostanes, F(3)-isoprostanes, F(4)-neuroprostanes, and F(2)-isoprostanes). A significant reduction in the clinical severity (in particular, motor-related signs, nonverbal communication deficits, and breathing abnormalities) together with a significant decrease in all the examined O.S. markers was observed in the ω-3 PUFAs supplemented patients, whereas no significant changes were evidenced in the untreated group. For the first time, these findings strongly suggest that a dietary intervention in this genetic disease at an early stage of its natural history can lead to a partial clinical and biochemical rescue.