n-3 fatty acids in the treatment of diabetic patients: biological rationale and clinical data

BAO-Ag-NPs as Promising Suppressor of ET-1/ICAM-1/VCAM-1 Signaling Pathway in ISO-induced AMI in Rats

OBJECTIVES

Acute myocardial infarction (AMI) is the most prevalent cause of myocardial fibrosis and the leading cause of mortality from cardiovascular disease. The goal of this work was to synthesize Balanites aegyptiaca oil-silver nanoparticles (BAO-Ag-NPs) and evaluate their cardioprotective effect against ISO-induced myocardial infarction in rats, as well as their mechanism.

MATERIALS AND METHODS

BAO was isolated, and the unsaturated fatty acids were estimated. BAO-Ag-NPs was prepared, LD50 was calculated to evaluate its cardioprotective activity against ISO (85 mg/kg)-induced AMI. Different doses of BAO-Ag-NPs (1/50 LD50; 46.6 mg/kg.b.w and 1/20 LD50; 116.5 mg) were received to the rats.

RESULTS

The total fatty acids and unsaturated fatty acids generated by BAO were 909.63 and 653.47 mg/100 g oil, respectively. Oleic acid methyl ester, 9-octadecenoic acid methyl ester, and 9, 12-Octadecadienoic acid methyl ester were the predominant ingredients, with concentrations of 107.6, 243.42, and 256.77 mg/100 g oil, respectively. According to TEM and DLS examinations, BAO-Ag-NPs have a size of 38.20 ± 2.5 nm and a negative zeta potential of -19.82 ± 0.30 mV, respectively. The LD50 of synthesized BAO-Ag-NPs is 2330 mg. On the other hand, BAOAg- NPs reduce myocardial necrosis by lowering increased BNP, cTnI, CK-MB, TC, TG, MDA, MMP2, TGF-β1, PGE2, and IL-6 levels. Furthermore, BAO-Ag-NPs inhibit the expression of ET-1, ICAM-1, and VCAM-1 genes as well as enhance HDL-C, CAT, and GSH levels when compared to the ISO-treated group of rats. Histopathological findings suggested that BAO-Ag- NPs enhance cardiac function by increasing posterior wall thickness in heart tissues.

CONCLUSION

BAO-Ag-NPs protect against AMI in vivo by regulating inflammation, excessive autophagy, and oxidative stress, as well as lowering apoptosis via suppression of the ET-1, ICAM-1, and VCAM-1 signaling pathways.

Effects of Fish Oil Supplementation on Reducing the Effects of Paternal Obesity and Preventing Fatty Liver in Offspring

Nonalcoholic fatty liver disease (NAFLD) is a serious public health concern, which calls for appropriate diet/nutrition intervention. Fish oil (FO) has several benefits in reducing obesity, but its intergenerational role in reducing the effects of paternal obesity has not been established. Hence, we hypothesized that FO supplementation to an obese father during the pre-conceptional period could improve the metabolic health of the offspring, specifically in the liver. Three groups of male mice were fed with a low-fat (LF), high-fat (HF), or high-fat diet supplemented with FO (HF-FO) for 10 weeks and were then allowed to mate with female mice fed a chow diet. Offspring were sacrificed at 16 weeks. The liver tissue was harvested for genomic and histological analyses. The offspring of HF and HF-FO fathers were heavier compared to that of the LF mice during 9-16 weeks. The glucose tolerance of the offspring of HF-FO fathers were significantly improved as compared to the offspring of HF fathers. Paternal FO supplementation significantly lowered inflammation and fatty acid synthesis biomarkers and increased fatty acid oxidation biomarkers in the offspring liver. In summary, FO supplementation in fathers shows the potential to reduce metabolic and cardiovascular diseases through genetic means in offspring.

Effects of omega-3 supplementation on glucose and lipid metabolism in patients with gestational diabetes: A meta-analysis of randomized controlled trials

AIM

We assessed whether omega-3 supplementation could improve glucose and lipid metabolism, insulin resistance, and inflammatory factors in individuals with gestational diabetes mellitus (GDM).

METHODS

In this meta-study, we used a random-effects or fixed-effects meta-analysis model to analyze the mean differences (MD) and corresponding 95 % confidence intervals (CI) before and after omega-3 and placebo supplementation, thus evaluating the effects of omega-3 on glucose and lipid metabolism, insulin resistance, and inflammatory factors.

RESULTS

Six randomized controlled trials (331 participants) were included in the meta-analysis. The levels of fasting plasma glucose (FPG) (WMD = -0.25 mmol/L; 95 % CI: -0.38, -0.12), fasting insulin (WMD = -17.13 pmol/L; 95 % CI: -27.95, -6.30), and homeostasis model of assessment-insulin resistance (WMD = -0.51; 95 % CI: -0.89, -0.12) were lower in the omega-3 group compared to their levels in the placebo group. The results of the analysis of lipid metabolism showed that triglycerides (WMD = -0.18 mmol/L; 95 % CI: -0.29, -0.08) and very low-density lipoprotein cholesterol (WMD = -0.1 mmol/L; 95 % CI: -0.16, -0.03) decreased in the omega-3 group, while high-density lipoproteins (WMD = 0.06 mmol/L; 95 % CI: 0.02, 0.10) increased. Compared to the placebo group, inflammatory factor serum C-reactive protein (SMD = -0.68 mmol/L; 95 % CI: -0.96, -0.39) decreased in the omega-3 group.

CONCLUSION

Omega-3 supplementation can decrease the levels of FPG and inflammatory factors, enhance blood lipid metabolism, and reduce insulin resistance in patients with GDM.

Suppression of Amyloid-β Adsorption on Endoplasmic Reticulum Stress-Mimicking Membranes by α-Tocopherol and α-Tocotrienol

Two forms of hydrophobic vitamin E (VE), α-tocopherol (Toc) and α-tocotrienol (Toc3), have been proposed to be effective against Alzheimer's disease (AD), the etiology of which is thought to involve endoplasmic reticulum (ER) stress. However, previous studies reported conflicting effects of Toc and Toc3 on the risk of AD. We prepared liposomes mimicking the phase separation of the ER membrane (solid-ordered/liquid-disordered phase separation) and studied how VE can influence the interaction between amyloid-β (Aβ) and the ER membrane. We found that Toc could inhibit the formation of the solid-ordered phase more significantly than Toc3. Furthermore, Aβ protofibril adsorption on ER stress-mimicking membranes was more strongly suppressed by Toc compared with Toc3. Therefore, we concluded that VE can relieve ER stress by destabilizing the solid-ordered phase of the ER membrane and subsequently reducing the amount of Aβ adsorbed on the membrane. Moreover, Toc exerted a stronger effect than Toc3.

Nutritional Values of Teff (Eragrostis tef) in Diabetic Patients: Narrative Review

Introduction

Teff (Eragrostis tef) is an indigenous crop in Ethiopia and exists in white, red, and mixed varieties. Several types of research confirmed that teff is rich in many essential amino acids, slowly digesting carbohydrates, essential fatty acids, minerals, vitamins, fibers, and other components. Since teff has a low glycemic index, is enriched in essential amino acids and fatty acids, and contains nutritionally balanced minerals, vitamins, and their precursors, it could be a promising food for the prevention and management of diabetes. People with diabetes mellitus are recommended to feed on a diet having a low glycemic index and enriched in essential nutrients.

Objective

This review aimed to summarize the nutritional composition of teff (Eragrostis tef) and its value in diabetic patients.

Methodology

We searched Web of Science, PubMed, Medline, Embase, and Google Scholar for studies on the nutritional composition of teff and its value for diabetic patients published in English since 2010.

Conclusion

According to available data, teff is a nutritionally valuable food type for diabetic patients.

Omega-3 Fatty Acids and Their Interaction with the Gut Microbiome in the Prevention and Amelioration of Type-2 Diabetes

Type-2 diabetes mellitus (T2DM) is often linked with hyperglycemia, disturbed lipid profiles, inflammation, and gut dysbiosis. Omega-3 fatty acid supplementation has a vital role in the management of T2DM. As a result, a better understanding of the potential role of omega-3 fatty acids in the development and progression of T2DM by influencing the intestinal microflora will help to improve the therapeutic intervention for T2DM and related complications. Focusing on the molecular mechanisms and signaling pathways induced by omega-3 fatty acids, this paper attempts to comprehensively review and discuss the putative associations between omega-3 fatty acids, gut dysbiosis, and the pathophysiology of T2DM and its related comorbidities. In addition, we contemplate the importance of gut microbiota in T2DM prevention and treatment and ponder the role of omega-3 fatty acids in T2DM by positively modulating gut microbiota, which may lead to discovery of novel targets and therapeutic strategies thereby paving way for further comprehensive, mechanistic, and clinical studies.

Metabolic and Metabolomic Insights Regarding the Omega-3 PUFAs Intake in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is currently considered an autoimmune disease characterized by the destruction of pancreatic β-cells, insulin deficiency, and dysglycemia. Dietary factors, including omega-3 polyunsaturated fatty acids (ω-3 PUFAs), were reported to influence T1DM. Therefore, a better understanding of the potential role of ω-3 PUFAs in the development and progression of T1DM will help to improve the clinical management of the disease. In this review, we explored the current understanding of molecular mechanisms and signaling pathways induced by ω-3 PUFAs and the beneficial effects of ω-3 PUFAs intake in the prevention and treatment of T1DM, as well as the underlying possible metabolomic (lipidomics) changes.

Effect of n-3 (Omega-3) Polyunsaturated Fatty Acid Supplementation on Metabolic and Inflammatory Biomarkers and Body Weight in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of RCTs

Beneficial effects of n-3 fatty acids on metabolic biomarkers in patients with type 2 diabetes (T2DM) has been reported. The objectives of this current research were to investigate the effects of n-3 supplementation on metabolic factors, weight, and body mass index (BMI) in patients with type 2 diabetes mellitus (T2DM), using a meta-analysis of randomized, controlled trials (RCTs). Online databases PubMed, Embase, Web of Science, and Science Direct were searched until 2021 to identify eligible articles. Thirty trials were included. The results showed that n-3 consumption can significantly reduce glycemic factors including fasting blood sugar (FBS) (−0.36 (−0.71 to −0.01)), glycated hemoglobulin (HbA1c) (−0.74 (−1.13 to −0.35)), and homeostatic model assessment of insulin resistance (HOMA.IR) (−0.58 (−1.13 to −0.03)). Furthermore, significant improvement in lipid profile including triglycerides (TG) (−0.27 (−0.37 to −0.18)), total cholesterol (−0.60 (−0.88 to −0.32)), low density lipoprotein (LDL) (−0.54 (−0.85 to −0.23)), and high-density lipoprotein (HDL) (0.60 (0.23 to 0.96)) levels were found in the present meta-analysis. The reduction in the inflammatory marker’s tumor necrosis factor-alpha (TNF-α) (−0.13 (−0.75 to 0.48)) and c-reactive protein (CRP) (−0.72 (−1.70 to 0.27)), as well as weight (−0.09 (−0.24 to 0.07)) and BMI (−0.13 (−0.29 to 0.02)) were not statistically significant. Furthermore, the findings revealed that the optimal dose and duration of n-3 consumption for patients with T2DM is 1000–2000 mg/d for more than 8 weeks. The present meta-analysis and review reveals that n-3 supplementation can improve glycemic factors and lipid profile in patients with T2DM. Furthermore, n-3 supplementation may provide beneficial effects on inflammatory markers and body weight if used at the appropriate dose and duration.

DHA inhibits Gremlin-1-induced epithelial-to-mesenchymal transition via ERK suppression in human breast cancer cells

Docosahexaenoic acid (DHA) is an omega-3 fatty acid abundant in fish oils. It is known to have an inhibitory effect on various diseases such as inflammation, diabetes, and cancer. Epithelial-to-mesenchymal transition (EMT) is a process that epithelial cells gain migratory property to become mesenchymal cells involved in wound healing, organ fibrosis, and cancer progression. Gremlin-1 (GREM1) is a bone morphogenetic protein antagonist known to play a role in EMT. However, the role of GREM1 in the induction of EMT in human breast cancer cells and the effect of DHA on GREM1-induced EMT remain unclear. Establishment of GREM1 knockdown cell lines was performed using lentiviral shRNAs. Expression of EMT markers was determined by qRT-PCR and Western blotting. Effect of GREM1 and/or DHA on cell migration was investigated using wound healing assay. The level of GREM1 expression in human breast cancer tissues was determined by Oncomine database mining. GREM1 induced the expression of genes including N-cadherin, vimentin, and Slug. GREM1 promoted the migration of human breast cancer cells. GREM1 enhanced the expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and the ERK activation was involved in EMT. Interestingly, DHA reduced the expression of GREM1. DHA also inhibited the expression of mesenchymal cell-associated genes and cell migration induced by GREM1. Furthermore, DHA suppressed the expression of p-ERK induced by GREM1. These results indicate that GREM1–ERK axis plays a role in EMT in human breast cancer cells and DHA is a putative compound that can inhibit EMT by inhibiting GREM1 signal transduction.

Effects of long-term vitamin D and n-3 fatty acid supplementation on inflammatory and cardiac biomarkers in patients with type 2 diabetes: secondary analyses from a randomised controlled trial

AIMS/HYPOTHESIS

Interventions that reduce inflammation may delay progression of microvascular and macrovascular complications in diabetes. We examined the effects of vitamin D₃ and/or n-3 fatty acid supplementation vs placebo on 5 year changes in serum inflammatory and cardiac biomarkers in adults with type 2 diabetes.

METHODS

This study reports pre-specified secondary outcomes of the Vitamin D and Omega-3 Trial to Prevent and Treat Diabetic Kidney Disease, in which 1312 US adults with type 2 diabetes and without known cardiovascular disease, malignancy, or end-stage kidney disease were randomised using computer-generated random numbers in blocks of eight to vitamin D₃ (2000 IU/day) vs placebo and n-3 fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]; 1 g/day) vs placebo in a 2 × 2 factorial design. Participants, examiners, and researchers assessing outcomes were blinded to intervention assignment. We measured serum IL-6, high-sensitivity C-reactive protein (hsCRP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) at baseline and after 2 and 5 years.

RESULTS

A total of 333 participants were randomised to vitamin D₃ and placebo n-3 fatty acids, 289 to n-3 fatty acids and placebo vitamin D₃, 370 to vitamin D₃ and n-3 fatty acids, and 320 to 2 placebos; 989 (75%) and 934 (71%) participants returned blood samples at 2 and 5 years, respectively. Participants had a mean age of 67.6 years (46% women). Overall, baseline geometric means of IL-6, hsCRP and NT-proBNP were 1.2 pg/ml, 1.9 mg/l and 262 ng/l, respectively. After 5 years, mean IL-6 and hsCRP remained within 6% of their baseline values while mean NT-proBNP increased by 55% overall. Compared with placebo, participants assigned to vitamin D₃ had a 1.24-fold greater increase in NT-proBNP over 5 years (95% CI 1.09, 1.41; p = 0.003), while IL-6 and hsCRP did not have a significant difference in change. Comparing n-3 fatty acids with placebo, there was no significant difference in change in IL-6, hsCRP or NT-proBNP. No heterogeneity was observed in subgroup analyses accounting for baseline eGFR, urine albumin to creatinine ratio, initial biomarker concentration, 25-hydroxyvitamin D level or EPA+DHA index.

CONCLUSIONS/INTERPRETATION

Among adults with type 2 diabetes, supplementation with vitamin D₃ or n-3 fatty acids did not reduce IL-6, hsCRP or NT-proBNP over 5 years.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01684722 FUNDING: The study was funded by grant R01DK088762 from the National Institute of Diabetes and Digestive and Kidney Diseases. Graphical abstract.

Deregulation of Lipid Homeostasis: A Fa(c)t in the Development of Metabolic Diseases

Lipids are important molecules for human health. The quantity and quality of fats consumed in the diet have important effects on the modulation of both the natural biosynthesis and degradation of lipids. There is an important number of lipid-failed associated metabolic diseases and an increasing number of studies suggesting that certain types of lipids might be beneficial to the treatment of many metabolic diseases. The aim of the present work is to expose an overview of de novo biosynthesis, storage, and degradation of lipids in mammalian cells, as well as, to review the published data describing the beneficial effects of these processes and the potential of some dietary lipids to improve metabolic diseases.

Dietary ω-3 fatty acids and their influence on inflammation via Toll-like receptor pathways

Dietary intake of long-chain, highly unsaturated ω-3 fatty acids (FAs) is considered indispensable for humans. The ω-3 FAs have been known to be anti-inflammatory and immunomodulatory dietary factors; however, the modes of action on pathogen recognition receptors (PRRs) and downstream signaling pathways have not been fully elucidated. Dietary sources contain various amounts of ω-3 long-chain fatty acids (LCFAs) of different lengths and the association between intake of these polyunsaturated fatty acids (PUFAs) with underlying mechanisms of various immune-related disorders can be of great interest. The potential anti-inflammatory role for ω-3 LCFAs can be explained by modification of lipid rafts, modulation of inflammatory mediators such as cytokines and PRRs. Toll-like receptors (TLRs) are a group of PRRs that play an important role in the recognition of bacterial infections and ω-3 FAs have been implicated in the modulation of downstream signaling of TLR-4, an important receptor for recognition of gram-negative bacteria. The ω-3 FAs docosahexaenoic acid and eicosapentaenoic acid have been investigated in vivo and in vitro for their effects on the nuclear factor-κB activation pathway. Identification of the effects of ω-3 FAs on other key molecular factors like prostaglandins and leukotrienes and their signals may help the recognition and development of medicines to suppress the main mediators and turn on the expression of anti-inflammatory cytokines and nuclear receptors.

Fish consumption and the risk of cardiovascular disease and mortality in patients with type 2 diabetes: a dose-response meta-analysis of prospective cohort studies

We aimed to investigate the association of fish consumption with the risk of coronary heart disease (CHD), stroke and all-cause mortality in patients with type 2 diabetes (T2D). We systematically searched PubMed and Scopus from inception till June 2019. We included prospective cohort studies assessing the relation of fish intake with the risk of CHD, stroke and mortality in patients with T2D. Study-specific results were pooled with the use of a random-effects model. Nine prospective cohort studies with 57,394 diabetic patients were identified. The relative risks for the highest compared with the lowest category of fish consumption were 0.86 (95% CI 0.76, 0.96; I² = 50%, n = 8) for all-cause mortality, and 0.61 (95% CI 0.29, 0.93; I² = 68%, n = 3) for CHD. There was a monotonic inverse association, with a nadir at fish consumption of approximately 2-3 servings/week, in both analyses. A nonsignificant inverse association was found for stroke. In the analysis of all-cause mortality, a nonsignificant inverse association was found in studies that controlled for energy intake, suggesting that the observed inverse association was not an addition effect, but may be due to substituting other foods such as red and processed meat with fish.

Diabetic Rat Hearts Show More Favorable Metabolic Adaptation to Omegaven Containing High Amounts of n3 Fatty Acids Than Intralipid Containing n6 Fatty Acids

BACKGROUND

While Omegaven, an omega-3 (n3) fatty acid-based lipid emulsion, fosters insulin signaling in healthy hearts, it is unknown whether beneficial metabolic effects occur in insulin-resistant diabetic hearts.

METHODS

Diabetic hearts from fructose-fed Sprague-Dawley rats were perfused in the working mode for 90 minutes in the presence of 11 mM glucose and 1.2 mM palmitate bound to albumin, the first 30 minutes without insulin followed by 60 minutes with insulin (50 mU/L). Hearts were randomly allocated to Intralipid (25 and 100 µM), Omegaven (25 and 100 µM), or no emulsion (insulin alone) for 60 minutes. Glycolysis, glycogen synthesis, and glucose oxidation were measured with the radioactive tracers [5-H]glucose and [U-C]glucose. Central carbon metabolites, acyl-coenzyme A species (acyl-CoAs), ketoacids, purines, phosphocreatine, acylcarnitines, and acyl composition of phospholipids were measured with mass spectrometry.

RESULTS

Diabetic hearts showed no response to insulin with regard to glycolytic flux, consistent with insulin resistance. Addition of either lipid emulsion did not alter this response but unexpectedly increased glucose oxidation (ratio of treatment/baseline, ie, fold change): no insulin 1.3 (0.3) [mean (standard deviation)], insulin alone 1.4 (0.4), insulin + 25 µM Intralipid 1.8 (0.5), insulin + 100 µM Intralipid 2.2 (0.4), P < .001; no insulin 1.3 (0.3), insulin alone 1.4 (0.4), insulin + 25 µM Omegaven 2.3 (0.5) insulin + 100 µM Omegaven 1.9 (0.4), P < .001. Intralipid treatment led to accumulation of acylcarnitines as a result of the released linoleic acid (C18:2-n6) and enhanced its integration into phospholipids, consistent with incomplete or impaired β-oxidation necessitating a compensatory increase in glucose oxidation. Accumulation of acylcarnitines was also associated with a higher nicotinamide adenine dinucleotide reduced/oxidized (NADH/NAD) ratio, which inhibited pyruvate dehydrogenase (PDH), and resulted in excess lactate production. In contrast, Omegaven-treated hearts showed no acylcarnitine accumulation, low malonyl-CoA concentrations consistent with activated β-oxidation, and elevated PDH activity and glucose oxidation, together indicative of a higher metabolic rate possibly by substrate cycling.

CONCLUSIONS

Omegaven is the preferred lipid emulsion for insulin-resistant diabetic hearts.

Therapeutic effects of different doses of prebiotic (isolated from Saccharomyces cerevisiae) in comparison to n-3 supplement on glycemic control, lipid profiles and immunological response in diabetic rats

BACKGROUND

The regular intake of fiber generates numerous health benefits. However, the efficacy depends on the duration of consumption and the ingested dose. Studies investigating the optimal dose are of interest to enable the inclusion of fiber in the routine treatment of diabetic patients.

OBJECTIVE

We aimed to evaluate the effects of different doses of β-glucan (BG-isolated from Saccharomyces cerevisiae), in comparison to n-3 supplement, on the inflammatory and metabolic parameters of Wistar rats induced to diabetes by streptozotocin.

METHODS

Forty animals were randomly divided into six groups receiving 0 mg/kg, 10 mg/kg, 20 mg/kg, or 40 mg/kg BG daily for 4 weeks or fish oil derivative [1000 mg/kg of omega-3 fatty acids (n-3)] for the same period. One additional group was composed of healthy controls. Serum metabolic and immunological parameters were evaluated by colorimetric and ELISA assays respectively. Histopathological analysis of the liver, small intestine and pancreas were also conducted. Significant changes due to BG intake were set into regression models with second-degree fit in order to estimate the optimal BG dose to achieve health benefits.

RESULTS

The animals that ingested BG had lower food and water intake (p < 0.05) than the negative control group (0 mg/kg). However, consumption was still elevated in comparison to healthy controls. Blood glucose and serum levels of total cholesterol, LDL-c, and TG (p < 0.05) reduced in comparison to diabetic animals without treatment (better or similar to n-3 group depending on dose), but did not reach normal levels (in comparison to healthy controls). HDL-c was not different (p > 0.05) among all groups. These reductions were already seen with the lowest dose of 10 mg/kg. On average, the serum levels of the hepatic enzymes ALT and AST were 40% and 60% lower in the BG groups in comparison to diabetic animals without treatment (better results than n-3 group). The group receiving 40 mg/kg reached similar values of healthy controls for ALT; whereas the same result occurred from the dose of 10 mg/kg for AST. The ideal dose, estimated from the mean of all metabolic parameters was approximately 30 mg/kg/day. Regarding the immunological profile, TNF-α significantly decreased in the BG groups compared to controls (p < 0.05), reaching better values than n-3 group and similar to healthy controls. No significant differences were found between the groups in IL-1β or IL-10 (p > 0.05). No histological changes were found in the pancreas, liver, or intestine due to treatment among diabetic animals.

CONCLUSIONS

BG significantly reduced blood glucose as well as serum total cholesterol, LDL-c and TG. There was a hepatoprotective effect due to the reduction in ALT and AST and a reduction in TNF-α, indicating a modulation of the immune response. In general, BG effects were better than n-3 supplement (or at least comparable) depending on the dose.

Curcumin and/or omega-3 polyunsaturated fatty acids supplementation reduces insulin resistance and blood lipids in individuals with high risk of type 2 diabetes: a randomised controlled trial

Background

Lowering insulin resistance and dyslipidaemia may not only enhance glycaemic control but also preserve the β-cell function, reducing the overall risk of developing type 2 diabetes (T2D). The current study was aimed to evaluate the effects of curcumin and/or long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) supplementation on glycaemic control and blood lipid levels in individuals at high risk of developing T2D.

Methods

This was a 2 × 2 factorial, randomised, double-blinded, placebo-controlled study. Participants were allocated to either double placebo (PL) or curcumin plus placebo matching for LCn-3PUFA (CC), or LCn-3PUFA plus placebo matching for curcumin (FO), or curcumin plus LCn-3PUFA (CC-FO) for twelve weeks. Primary outcome of the trial was glycaemic indices (HbA1C, fasting glucose and insulin). Insulin resistance and sensitivity is measured using homeostatic model assessment model.

Results

A total of sixty-four participants (PL, n = 16; CC, n = 15; FO, n = 17, CC-FO, n = 16) were included in the final analysis. Post-intervention, HbA1c and fasting glucose remained unchanged across all the groups. Insulin sensitivity was significantly improved in the CC supplemented group (32.7 ± 10.3%) compared to PL (P = 0.009). FO and CC-FO tended to improve insulin sensitivity by 14.6 ± 8.5% and 8.8 ± 7.7% respectively, but the difference did not reach significance. Triglyceride levels were further increased in the PL (26.9 ± 7.4%), however, CC and CC-FO supplementation reduced the triglycerides, FO resulted in the greatest reduction in triglycerides (− 16.4 ± 4.5%, P < 0.001).

Conclusion

Reduction in insulin resistance and triglycerides by curcumin and LCn-3PUFA appears to be attractive strategies for lowering the risk of developing T2D. However, this study failed to demonstrate complimentary benefits of curcumin and LCn-3PUFA on glycaemic control.

Trail registration

ACTRN12615000559516.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-0967-x) contains supplementary material, which is available to authorized users.

The combination of canagliflozin and omega-3 fatty acid ameliorates insulin resistance and cardiac biomarkers via modulation of inflammatory cytokines in type 2 diabetic rats

The present study was carried out with the hypothesis that combination of canagliflozin and omega-3 fatty acid may have potential effect on insulin level, insulin resistance, cardiac biomarkers, inflammatory cytokines and histological studies in type 2 diabetes mellitus (DM). Type 2 DM was induced by injecting nicotinamide (120 mg/kg, i.p.) 15 min before STZ (60 mg/kg) injection. Canagliflozin (5 and 10 mg/kg) and omega-3 fatty acid (300 mg/kg) were given for 28 days after confirmation of diabetes. Biochemical estimations revealed elevated levels of glucose, insulin, HOMA-R and inflammatory cytokines in diabetic group. Daily dosing of alone canagliflozin and omega-3 fatty acid slightly reduced elevated levels of glucose, insulin, HOMA-R and inflammatory cytokines (IL-1β, IL-2, and TNFα), whereas canagliflozin and omega-3 fatty acid combination has reduced these biochemical parameters significantly when compared with diabetic group. Similarly in diabetic group the levels of cardiac biomarkers such as lipid profile, LDH, CKMB and troponin were significantly increased. Elevated levels of cardiac biomarkers were significantly reduced after daily dosing of alone canagliflozin and omega-3 fatty acid. Canagliflozin and omega-3 fatty acid combination has offered better improvement in cardiac biomarkers compared to alone canagliflozin and omega-3 fatty acid. Histopathological analysis also supported the above hypothesis that combination therapy (canagliflozin and omega-3 fatty acid) offered better protection against degenerative changes in β-cells of pancreas as compared to alone treatment with these drugs. Thus the present study revealed that canagliflozin and omega-3 fatty acid can be used as potential combination therapy in type 2 DM along with cardiac complication.

Effects of dapagliflozin and n-3 carboxylic acids on non-alcoholic fatty liver disease in people with type 2 diabetes: a double-blind randomised placebo-controlled study

AIMS/HYPOTHESIS

The EFFECT-II study aimed to investigate the effects of dapagliflozin and omega-3 (n-3) carboxylic acids (OM-3CA), individually or combined, on liver fat content in individuals with type 2 diabetes and non-alcoholic fatty liver disease (NAFLD).

METHODS

This randomised placebo-controlled double-blind parallel-group study was performed at five clinical research centres at university hospitals in Sweden. 84 participants with type 2 diabetes and NAFLD were randomly assigned 1:1:1:1 to four treatments by a centralised randomisation system, and all participants as well as investigators and staff involved in the study conduct and analyses were blinded to treatments. Each group received oral doses of one of the following: 10 mg dapagliflozin (n = 21), 4 g OM-3CA (n = 20), a combination of both (n = 22) or placebo (n = 21). The primary endpoint was liver fat content assessed by MRI (proton density fat fraction [PDFF]) and, in addition, total liver volume and markers of glucose and lipid metabolism as well as of hepatocyte injury and oxidative stress were assessed at baseline and after 12 weeks of treatment (completion of the trial).

RESULTS

Participants had a mean age of 65.5 years (SD 5.9), BMI 31.2 kg/m² (3.5) and liver PDFF 18% (9.3). All active treatments significantly reduced liver PDFF from baseline, relative changes: OM-3CA, -15%; dapagliflozin, -13%; OM-3CA + dapagliflozin, -21%. Only the combination treatment reduced liver PDFF (p = 0.046) and total liver fat volume (relative change, -24%, p = 0.037) in comparison with placebo. There was an interaction between the PNPLA3 I148M polymorphism and change in liver PDFF in the active treatment groups (p = 0.03). Dapagliflozin monotherapy, but not the combination with OM-3CA, reduced the levels of hepatocyte injury biomarkers, including alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase (γ-GT), cytokeratin (CK) 18-M30 and CK 18-M65 and plasma fibroblast growth factor 21 (FGF21). Changes in γ-GT correlated with changes in liver PDFF (ρ = 0.53, p = 0.02). Dapagliflozin alone and in combination with OM-3CA improved glucose control and reduced body weight and abdominal fat volumes. Fatty acid oxidative stress biomarkers were not affected by treatments. There were no new or unexpected adverse events compared with previous studies with these treatments.

CONCLUSIONS/INTERPRETATION

Combined treatment with dapagliflozin and OM-3CA significantly reduced liver fat content. Dapagliflozin monotherapy reduced all measured hepatocyte injury biomarkers and FGF21, suggesting a disease-modifying effect in NAFLD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02279407 FUNDING: The study was funded by AstraZeneca.

Effects of free omega-3 carboxylic acids and fenofibrate on liver fat content in patients with hypertriglyceridemia and non-alcoholic fatty liver disease: A double-blind, randomized, placebo-controlled study

BACKGROUND

Treatment with omega-3 fatty acids and fenofibrates reduces serum triglyceride levels, but few studies have compared the effect of these agents on liver fat.

OBJECTIVE

The aim of the EFFECT I trial (NCT02354976) was to determine the effects of free omega-3 carboxylic acids (OM-3CA) and fenofibrate on liver fat in overweight or obese individuals with non-alcoholic fatty liver disease and hypertriglyceridemia.

METHODS

Seventy-eight patients were randomized to receive oral doses of 4 g OM-3CA (n = 25), 200 mg fenofibrate (n = 27), or placebo (n = 26) for 12 weeks in a double-blind, parallel-group study. Liver proton density fat fraction (PDFF) and volume, pancreas volume, and adipose tissue volumes were assessed by magnetic resonance imaging.

RESULTS

Changes in liver PDFF at 12 weeks were not significantly different across treatment groups (relative changes from baseline: placebo, +4%; OM-3CA, -2%; and fenofibrate, +17%). The common PNPLA3 genetic polymorphism (I148M) did not significantly influence the effects of OM-3CA or fenofibrate on liver PDFF. Fenofibrate treatment significantly increased liver and pancreas volumes vs placebo treatment, and the changes in liver and pancreas volumes were positively correlated (rho 0.45, P = .02). Total liver fat volume increased significantly in patients using fenofibrate vs OM-3CA (+23% vs -3%, P = .04). Compared with OM-3CA, fenofibrate increased total liver fat and liver volume. Serum triglycerides decreased with OM-3CA (-26%, P = .02) and fenofibrate (-38%, P < .001) vs placebo. In contrast to OM-3CA, fenofibrate reduced plasma docosahexaenoic acid levels and increased plasma acetylcarnitine and butyrylcarnitine levels, estimated delta-9 desaturase activity and the concentration of urine F2-isoprostanes.

CONCLUSIONS

OM-3CA and fenofibrate reduced serum triglycerides but did not reduce liver fat. Fenofibrate increased total liver volume and total liver fat volume vs OM-3CA, indicating a complex effect of fenofibrate on human hepatic lipid metabolism.

Comparing isolated soy protein with flaxseed oil vs isolated soy protein with corn oil and wheat flour with corn oil consumption on muscle catabolism, liver function, blood lipid, and sugar in burn patients: a randomized clinical trial

BACKGROUND

There is controversy regarding whether increasing isolated soy protein (ISP) with or without flaxseed oil (FO), as functional foods, would lead to reduce muscle catabolism and cachexia in burn patients.

METHODS

One hundred and eighty-eight patients were assessed for eligibility in this randomized controlled trial. Of these, seventy-three eligible patients (total burn surface area 20-50%) were randomly assigned to three groups, labeled as Control (wheat flour [WF] + corn oil [CO]), ISP + FO, and ISP + CO, to receive these nutrients for three weeks. Weight, body mass index (BMI), serum hepatic enzymes (alanine transaminase [ALT], aspartate transaminase [AST], alkaline phosphatase [ALP]), systemic inflammatory response syndrome (SIRS), 24-h urinary urea nitrogen excretion (UUN), serum creatinine, 24-h urinary creatinine (UUC) excretion, fasting blood sugar (FBS), triglyceride (TG), and cholesterol were measured.

RESULTS

Using analysis of covariance models in the intention-to-treat population (n = 73), we found that at three weeks, patients in the ISP groups had lost significantly less in weight and BMI compared to those in the control group (all P < 0.01). Nitrogen retention and serum creatinine (primary outcomes) increased significantly in the ISP groups compared with the control group. Even after controlling for potential covariates in ANCOVA models, changes in these indices were still statistically significant (P = 0.008 and P = 0.005 for nitrogen balance and serum creatinine, respectively). However, no such significant differences were found between the ISP groups. On the other hand, 24-h UUN, and UUC excretion, serum hepatic enzymes, FBS, TG, and cholesterol were not significant between the groups (P > 0.05).

CONCLUSION

ISP and FO compared to WF and CO reduced muscle catabolism and increased body weight in burn patients.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials, IRCT2014051817740N1 . Registered on 27 June 2014.

Function of Pro-Resolving Lipid Mediator Resolvin E1 in Type 2 Diabetes

Programming of inflammation resolution is governed by a class of specialized pro-resolving lipid mediators (SPMs) that act in concert to modulate epithelial, endothelial, and immune cell function for restoration of homeostasis. The resolution circuits are altered in obesity and associated morbidities, including type 2 diabetes mellitus (T2D), through reduced production and/or action of SPMs, which can be rescued by therapeutic SPM delivery or up-regulation of SPM receptors. Resolvin E1 (RvE1), an eicosapentaenoic acid derivative, has potent pro-resolving and insulin-sensitizing actions mediated by BLT1 and ERV1 receptors in the vasculature and metabolic organs. Nonetheless, the RvE1-mediated increase in protective adipokines such as adiponectin in white adipose tissues, the enhancement of monocyte patrolling function in the vasculature, as well as the macrophage-clearing functions improve metabolic control in obese-prone conditions. RvE1-enhanced resolving function in obesity prevents dysbiosis of the gut microflora and increased gut permeability. These functions suggest that RE1 has therapeutic potential for immunometabolic alterations associated with T2D in patients with reduced inflammation resolving capacity. SPM profiling in individuals at risk for T2D and associated complications will help to advance personalized disease management and precision medicine.

Dietary interventions to contrast the onset and progression of diabetic nephropathy: A critical survey of new data

This article is a critical overview of recent contributions on the dietary corrections and the foods that have been claimed to delay or hinder the onset of diabetic nephropathy (DN) and its progression to end-stage renal disease. Innovative dietary and behavioral approaches to the prevention and therapy of DN appear to be the most captivating in consideration of the rather well-established protocols for glucose and blood pressure control in use. In addition to restricted caloric intake to contrast obesity and the metabolic syndrome, adjustments in the patient's macronutrients intake, and in particular some degree of reduction in protein, have been long considered in the prevention of DN progression. More recently, the focus has shifted to the source of proteins and the content of glycotoxins in the diet as well as to the role of specific micronutrients. Few clinical trials have specifically addressed the role of those micronutrients associated with diet proteins that show the most protective effect against DN. Research on clinical outcome and mechanisms of action of such micronutrients appears the most promising in order to develop both effective intervention on nutritional education of the patient and selection of functional foods capable of contrasting the onset and progression of DN.

Wound Healing Studies Using Punica granatum Peel: An Animal Experimental Study

OBJECTIVE

The goal of the present study was to evaluate the effects of hydroalcoholic extract-based carboxy methyl cellulose (CMC) gel of Punica granatum peel (PCMC) and CMC on healing of full-thickness skin wounds.

MATERIALS AND METHODS

Forty-two rats were studied. Each rat had 3 wounds that were treated topically with PCMC as the case, CMC as the positive control, and sterile saline as the negative control. All 3 wounds of each rat were photographed during the wound healing period at days 0 (onset of wound surgery), 3, 6, 9, and 12.The wound area was calculated using Adobe Photoshop CS (version 5) software (Adobe Systems Inc, San Jose, California). Electrocardiogram paper was used for reference scale.

RESULTS

The results of this study show that macroscopic and microscopic wound healing took a significantly longer time in wounds treated with normal saline than those treated with PCMC (grossly) and CMC gel (grossly and significantly).

CONCLUSIONS

The authors' findings show that anti-inflammatory, antihemorrhagic, and antinecrotic effects of CMC lead to early healing of skin wounds.

Flaxseed oil supplementation manipulates correlations between serum individual mol % free fatty acid levels and insulin resistance in type 2 diabetics. Insulin resistance and percent remaining pancreatic β-cell function are unaffected

Objectives. Elevated total serum free fatty acids (FFAs) concentrations have been suggested, controversially, to enhance insulin resistance and decrease percent remaining β-cell function. However, concentrations of individual serum FFAs have never been published in terms of their relationship (correlation) to homeostatic model assessment-insulin resistance (HOMA-IR) and percent remaining β-cell function (HOMA-%β) in the type 2 diabetics (T2Ds). Alpha-linolenic acid consumption has a negative correlation with the insulin resistance, which in turn is negatively correlated with the remaining β-cell function. The primary objective was to test the hypothesis that there would be different relationship (correlation) between the blood serum individual free FFA mol % levels and HOMA-IR and/or HOMA-%β in T2D. The secondary objective was to test the hypothesis that flaxseed oil, previously being shown to be ineffective in the glycemic control in T2Ds, may alter these correlations in a statistically significant manner as well as HOMA-IR and/or HOMA-%β.

Methods. Patients were recruited via a newspaper advertisement and two physicians have been employed. All the patients came to visit one and three months later for a second visit. At the second visit, the subjects were randomly assigned (double blind) to flaxseed or safflower oil treatment for three months, until the third visit.

Results. Different statistically significant correlations or trends towards among some serum individual free FFA mol % levels and HOMA-IR and HOMA-%β, pre- and post-flaxseed and safflower oil supplementation were found. However, flaxseed oil had no impact on HOMA-IR or HOMA-%β despite statistically significant alterations in correlations compared to baseline HOMA-IR.

Conclusions. The obtained data indicate that high doses of flaxseed oil have no statistically significant effect on HOMA-IR or HOMA-%β in T2Ds, probably due to the additive effects of negative and positive correlations.

Curcumin and long-chain Omega-3 polyunsaturated fatty acids for Prevention of type 2 Diabetes (COP-D): study protocol for a randomised controlled trial

Background

Lifestyle interventions, including increase in physical activity and dietary counselling, have shown the ability to prevent type 2 diabetes (T2D) in high-risk state individuals, but the prevalence is still skyrocketing in Australia, in line with global prevalence. Currently, no medicines are approved by the Therapeutic Goods Administration in Australia for the management of prediabetes. Therefore, there is a need of developing a safer, biologically efficacious and cost-effective alternative for delaying the transition of individual health state from prediabetes into T2D. In the current trial we propose to evaluate the effects of curcumin and/or long-chain omega-3 polyunsaturated fatty acids on improving glycosylated haemoglobin as a primary outcome, along with secondary outcomes of glycaemic indices, lipid profile and inflammatory parameters.

Methods/design

Eighty individuals diagnosed with prediabetes, aged between 30 and 70 years, will be randomly assigned to double placebo, curcumin alone, fish oil alone or double active groups according to a computer-generated randomisation sequence for 12 weeks. At baseline and post-intervention visits participants will be asked to provide blood samples and undergo body composition measurements. A blood sample is used for estimating glycaemic profiles, lipid profiles and inflammatory parameters (C-reactive protein, whole blood cell count, adiponectin, leptin, interleukin-6). The interim visit includes review on compliance with supplements based on capsule log and capsule count, adverse events and anthropometric measurements. In addition to these procedures, participants provide self-reported questionnaires on dietary intake (using a 3-day food record), a physical activity questionnaire and medical history.

Discussion

This trial aims to determine whether curcumin and/or long-chain omega-3 polyunsaturated fatty acids affect surrogate markers of glycaemic control which is relevant to delaying T2D. To date 38 participants completed the trial. No changes have been made to the clinical protocol post recruitment. If successful, this trial will provide considerable evidence for performing a larger trial to investigate whether this combination can be administered for preventing or delaying the onset of T2D in high-risk individuals.

Trial registration

ACTRN12615000559516, registered on 29 May 2015).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1702-9) contains supplementary material, which is available to authorized users.

Effect of Treatment with Salsalate, Menhaden Oil, Combination of Salsalate and Menhaden Oil, or Resolvin D1 of C57Bl/6J Type 1 Diabetic Mouse on Neuropathic Endpoints

Aims. In this study a streptozotocin induced type 1 diabetes mouse model was used to assess the effectiveness of salsalate, menhaden oil, the combination of salsalate and menhaden oil, or resolvin D1 on neuropathic endpoints. Materials and Methods. Changes in body weight, blood glucose, serum markers for triglycerides, free fatty acids, cholesterol, and resolvin D1, motor and sensory nerve conduction velocities and thermal sensitivity were assessed, as well as performing in vivo confocal microscopy of subepithelial corneal nerves and immunohistochemistry of nerves in the cornea and foot pad. Results. Diabetic animals failed to gain weight and had elevated blood glucose levels. Diabetic mice had slowed nerve conduction velocity, reduced innervation of the foot pad and cornea subepithelial and epithelial layers, and reduced thermal sensitivity. Monotherapy treatment with salsalate, menhaden oil, and resolvin D1 reduced the pathological signs of diabetic neuropathy. The combination of salsalate and menhaden oil also reduced signs of pathology and generated elevated plasma levels of resolvin D1 compared to other groups. Conclusions. Additional studies are needed to determine whether the combination of salsalate and menhaden oil may be more efficacious than monotherapy alone for the treatment of diabetic peripheral neuropathy.

The effects of n-3 long-chain polyunsaturated fatty acid supplementation on AGEs and sRAGE in type 2 diabetes mellitus

In diabetes mellitus, chronic hyperglycemia leads to formation of advanced glycation end products (AGEs). Binding of AGEs to receptors of AGE (RAGE) causes deleterious effects. In populations with a high consumption of n-3 long-chain polyunsaturated fatty acids, a lower prevalence of diabetes mellitus has been reported. We aimed to investigate the effects of n-3 fatty acid (EPA and DHA) supplementation on the levels of AGEs (carboxymethyl lysine (CML) and pentosidine), sRAGE, and nuclear factor kappa B (NF-kB) in type 2 diabetes mellitus (T2DM). T2DM patients (n = 38) treated with oral hypoglycemic agents, without insulin were supplemented with n-3 fatty acids (1.2 g/day) for 2 months. Plasma CML, pentosidine, sRAGE, and NF-kB levels were measured by ELISA both before and after the supplementation. n-3 fatty acid supplementation significantly reduced fasting glucose (p < 0.01), glycated hemoglobin (HbA_1c) (p < 0.05), and pentosidine (p < 0.05) levels. The supplementation induced percentage changes in pentosidine and HbA_1c and in pentosidine and creatinine were observed to be correlated (r = 0.349, p < 0.05) and (r = 0.377, p < 0.05), respectively. Waist circumference and systolic and diastolic pressures were significantly decreased due to n-3 supplementation (p < 0.001, p < 0.01, p < 0.01), respectively. Our results show that supplementation with n-3 fatty acid has beneficial effects on waist circumference; systolic and diastolic blood pressures; and the levels of glucose, HbA_1c, and pentosidine in T2DM patients. However, the supplementation failed to decrease these parameters to the reference ranges for healthy subjects. In addition, the supplementation did not appear to induce any significant differences in CML, sRAGE, or NF-kB.

Omega-3 polyunsaturated fatty acids and cancer: lessons learned from clinical trials

Over the past decades, extensive studies have addressed the therapeutic effects of omega-3 polyunsaturated fatty acids (omega-3 FAs) against different human diseases such as cardiovascular and neurodegenerative diseases, cancer, etc. A growing body of scientific research shows the pharmacokinetic information and safety of these natural occurring substances. Moreover, during recent years, a plethora of studies has demonstrated that omega-3 FAs possess therapeutic role against certain types of cancer. It is also known that omega-3 FAs can improve efficacy and tolerability of chemotherapy. Previous reports showed that suppression of nuclear factor-κB, activation of AMPK/SIRT1, modulation of cyclooxygenase (COX) activity, and up-regulation of novel anti-inflammatory lipid mediators such as protectins, maresins, and resolvins, are the main mechanisms of antineoplastic effect of omega-3 FAs. In this review, we have collected the available clinical data on the therapeutic role of omega-3 FAs against breast cancer, colorectal cancer, leukemia, gastric cancer, pancreatic cancer, esophageal cancer, prostate cancer, lung cancer, head and neck cancer, as well as cancer cachexia. We also discussed the chemistry, dietary source, and bioavailability of omega-3 FAs, and the potential molecular mechanisms of anticancer and adverse effects.

Evaluation of the effect of n-3 PUFA-rich dietary fish oils on lipid profile and membrane fluidity in alloxan-induced diabetic mice (Mus musculus)

Marine fishes are important to health due to their high content of polyunsaturated fatty acids particularly those of the omega-3 family. These fatty acids play an important role in various physiological processes and as a consequence they may modulate and even prevent some human diseases. The aim of the present study was to investigate and compare the effect of fish oils of different origins (Sardinella longiceps, Rastrelliger kanagurta and Clarias batrachus) on lipid metabolism and membrane fluidity in diabetes. Alloxan was injected in repetitive doses for 1 month (100 mg/kg body weight every 5th day) to induce diabetes in Swiss albino mice. 10 % S. longiceps, R. kanagurta or C. batrachus fish oil was freshly blended with pellet feed which was provided to diabetic mice for 1 month. The serum lipid profile (serum total cholesterol, triglyceride, HDL, VLDL and LDL) along with liver, kidney and heart tissue lipid profile (i.e. triglyceride, total cholesterol, glycolipid and phospholipid) was analysed. Besides, the enzymatic activity of HMG-CoA reductase, HMG-CoA synthase and glucose-6-phosphate-dehydrogenase along with the membrane fluidity of these tissues was evaluated. Altered tissue lipid composition, enzyme activities and membrane fluidity due to diabetes were returned towards normal with the supplementation of 10 % fish oils. Fish oil from S. longiceps brought maximum changes in level of neutral lipid composition in heart, and increased the concentration of phospholipid and decreased the activity of HMG-CoA reductase in comparison with the fish oil from R. kanagurta and C. batrachus.

Marine omega-3 highly unsaturated fatty acids: From mechanisms to clinical implications in heart failure and arrhythmias

Therapeutic implications of marine omega-3 highly unsaturated fatty acids (HUFA) in cardiovascular disease are still discussed controversially. Several clinical trials report divergent findings and thus leave ambiguity on the meaning of oral omega-3 therapy. Potential prognostic indications of HUFA treatment have been predominantly studied in coronary artery disease, sudden cardiac death, ventricular arrhythmias, atrial fibrillation and heart failure of various origin. It is suspected that increased ventricular wall stress is crucially involved in the prognosis of heart failure. Increased wall stress and an unfavorable myocardial remodeling is associated with an increased risk of arrhythmias by stretch-activated membrane ion channels. Integration of HUFA into the microenvironment of cardiomyocyte ion channels lead to allosteric changes and increase the electrical stability. Increased ventricular wall stress appears to be involved in the local myocardial as well as in the hepatic fatty acid metabolism, i.e. a cardio-hepatic syndrome. Influences of an altered endogenous HUFA metabolism and an inverse shift of the fatty acid profile was underrated in the past. A better understanding of these interacting endogenous mechanisms appears to be required for interpreting the findings of recent experimental and clinical studies. The present article critically reviews major studies on basic pathophysiological mechanisms and treatment effects in clinical trials.

Targeting inflammation in metabolic syndrome

The metabolic syndrome (MetS) is comprised of a cluster of closely related risk factors, including visceral adiposity, insulin resistance, hypertension, high triglyceride, and low high-density lipoprotein cholesterol; all of which increase the risk for the development of type 2 diabetes and cardiovascular disease. A chronic state of inflammation appears to be a central mechanism underlying the pathophysiology of insulin resistance and MetS. In this review, we summarize recent research which has provided insight into the mechanisms by which inflammation underlies the pathophysiology of the individual components of MetS including visceral adiposity, hyperglycemia and insulin resistance, dyslipidemia, and hypertension. On the basis of these mechanisms, we summarize therapeutic modalities to target inflammation in the MetS and its individual components. Current therapeutic modalities can modulate the individual components of MetS and have a direct anti-inflammatory effect. Lifestyle modifications including exercise, weight loss, and diets high in fruits, vegetables, fiber, whole grains, and low-fat dairy and low in saturated fat and glucose are recommended as a first line therapy. The Mediterranean and dietary approaches to stop hypertension diets are especially beneficial and have been shown to prevent development of MetS. Moreover, the Mediterranean diet has been associated with reductions in total and cardiovascular mortality. Omega-3 fatty acids and peroxisome proliferator-activated receptor α agonists lower high levels of triglyceride; their role in targeting inflammation is reviewed. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone blockers comprise pharmacologic therapies for hypertension but also target other aspects of MetS including inflammation. Statin drugs target many of the underlying inflammatory pathways involved in MetS.

Endogenously elevated n-3 polyunsaturated fatty acids alleviate acute ethanol-induced liver steatosis

Effective means for the prevention of alcohol-induced liver disease, a global health problem, have yet to be developed. We evaluated whether the high endogenous levels of omega-3 polyunsaturated acids (n-3 PUFA) in fat-1 transgenic mice could protect them against acute ethanol-induced liver steatosis. We induced alcoholic liver steatosis in 9-week-old male heterozygous fat-1 mice and their wild-type (WT) male littermates through three oral gavages of 60% ethanol at 4.7 g/kg body weight. Hepatic lipid accumulation was significantly increased in both alcohol treatment groups, but by much less in the fat-1 group compared with the WT group. Fat-1 mice exhibited significantly lower levels of total hepatic/plasma TG and plasma alanine aminotransferase activity. Accordingly, hepatic expression of lipogenesis-related genes (e.g., SREBP-1c, FAS, and SCD-1) and plasma levels of inflammatory cytokines (e.g., IL-6, TNF-α, and MCP-1) were reduced in the fat-1 mice. Furthermore, decreased hepatic expression of cytochrome P450 2E1 (CYP2E1) and increased hepatic levels of PPAR-α and HO-1 were observed in the fat-1 mice, compared to the WT mice. These findings show that elevated tissue n-3 PUFA protect against acute ethanol-induced liver steatosis in fat-1 mice, possibly through the down-regulation of hepatic lipogenesis, inflammatory response, and oxidative stress.

Prevention of diabetes-promoted colorectal cancer by (n-3) polyunsaturated fatty acids and (n-3) PUFA mimetic

The global obesity / diabetes epidemic has resulted in robust increase in the incidence of colorectal cancer (CRC). Epidemiological, animal and human studies have indicated efficacy of (n-3) PUFA in chemoprevention of sporadic and genetic-driven CRC. However, diabetes-promoted CRC presents a treatment challenge that surpasses that of sporadic CRC. This report analyzes the efficacy of (n-3) PUFA generated by the fat-1 transgene that encodes an (n-6) to (n-3) PUFA desaturase, and of synthetic (n-3) PUFA mimetic (MEDICA analog), to suppress CRC development in carcinogen-induced diabetes-promoted animal model. Carcinogen-induced CRC is shown here to be promoted by the diabetes context, in terms of increased aberrant crypt foci (ACF) load, cell proliferation and epithelial dedifferentiation, being accompanied by increase in the expression of HNF4α, β-catenin, and β-catenin-responsive genes. Incorporating the fat-1 transgene in the diabetes context, or oral MEDICA treatment, resulted in ameliorating the diabetic phenotype and in abrogating CRC, with decrease in ACF load, cell proliferation and the expression of HNF-4α, β-catenin, and β-catenin-responsive genes. The specificity of (n-3) PUFA in abrogating CRC development, as contrasted with enhancing CRC by (n-6) PUFA, was similarly verified in CRC cell lines. These findings may indicate prospective therapeutic potential of (n-3) PUFA or MEDICA in the management of CRC, in particular diabetes-promoted CRC.

Moderate oral supplementation with docosahexaenoic acid improves platelet function and oxidative stress in type 2 diabetic patients

Platelets from patients with type 2 diabetes are characterised by hyperactivation and high level of oxidative stress. Docosahexaenoic acid (DHA) may have beneficial effects on platelet reactivity and redox status. We investigated whether moderate DHA supplementation, given as a triglyceride form, may correct platelet dysfunction and redox imbalance in patients with type 2 diabetes. We conducted a randomised, double-blind, placebo-controlled, two-period crossover trial (n=11 post-menopausal women with type 2 diabetes) to test the effects of 400 mg/day of DHA intake for two weeks on platelet aggregation, markers of arachidonic acid metabolism, lipid peroxidation status, and lipid composition. Each two week-period was separated from the other by a six-week washout. Daily moderate dose DHA supplementation resulted in reduced platelet aggregation induced by collagen (-46.5 %, p< 0.001), and decreased platelet thromboxane B2 (-35 %, p< 0.001), urinary 11-dehydro-thromboxane B2 (-13.2 %, p< 0.001) and F2-isoprostane levels (-19.6 %, p< 0.001) associated with a significant increase of plasma and platelet vitamin E concentrations (+20 % and +11.8 %, respectively, p< 0.001). The proportions of DHA increased both in plasma lipids and in platelet phospholipids. After placebo treatment, there was no effect on any parameters tested. Our findings support a significant beneficial effect of low intake of DHA on platelet function and a favourable role in reducing oxidative stress associated with diabetes.

Combination therapies prevent the neuropathic, proinflammatory characteristics of bone marrow in streptozotocin-induced diabetic rats

We previously showed that peripheral neuropathy of the bone marrow was associated with loss of circadian rhythmicity of stem/progenitor cell release into the circulation. Bone marrow neuropathy results in dramatic changes in hematopoiesis that lead to microvascular complications, inflammation, and reduced endothelial repair. This series of events represents early pathogenesis before development of diabetic retinopathy. In this study we characterized early alterations within the bone marrow of streptozotocin (STZ)-induced diabetic rats following treatments that prevent experimental peripheral neuropathy. We asked whether bone marrow neuropathy and the associated bone marrow pathology were reversed with treatments that prevent peripheral neuropathy. Three strategies were tested: inhibition of neutral endopeptidase, inhibition of aldose reductase plus lipoic acid supplementation, and insulin therapy with antioxidants. All strategies prevented loss of nerve conduction velocity resulting from STZ-induced diabetes and corrected the STZ-induced diabetes-associated increase of immunoreactivity of neuropeptide Y, tyrosine hydroxylase, and somatostatin. The treatments also reduced concentrations of interleukin-1β, granulocyte colony-stimulating factor, and matrix metalloproteinase 2 in STZ-induced diabetic bone marrow supernatant and decreased the expression of NADPH oxidase 2, nitric oxide synthase 2, and nuclear factor-κB1 mRNA in bone marrow progenitor cells. These therapies represent novel approaches to attenuate the diabetic phenotype within the bone marrow and may constitute an important therapeutic strategy for diabetic microvascular complications.

Safety assessment of docosahexaenoic acid in X-linked retinitis pigmentosa: the 4-year DHAX trial

PURPOSE

Docosahexaenoic acid (DHA) continues to be evaluated and recommended as treatment and prophylaxis for various diseases. We recently assessed efficacy of high-dose DHA supplementation to slow vision loss in patients with X-linked retinitis pigmentosa (XLRP) in a randomized clinical trial. Because DHA is a highly unsaturated fatty acid, it could serve as a target for free-radical induced oxidation, resulting in increased oxidative stress. Biosafety was monitored during the 4-year trial to determine whether DHA supplementation was associated with identifiable risks.

METHODS

Males (n = 78; 7-31 years) meeting entry criteria were enrolled. The modified intent-to-treat cohort (DHA = 33; placebo = 27) adhered to the protocol ≥ 1 year. Participants were randomized to an oral dose of 30 mg/kg/d DHA or placebo plus a daily multivitamin. Comprehensive metabolic analyses were assessed for group differences. Treatment-emergent adverse events including blood chemistry metabolites were recorded.

RESULTS

By year 4, supplementation elevated plasma and red blood cell-DHA 4.4- and 3.6-fold, respectively, compared with the placebo group (P < 0.00001). Over the trial duration, no significant differences between DHA and placebo groups were found for vitamin A, vitamin E, platelet aggregation, antioxidant activity, lipoprotein cholesterol, or oxidized LDL levels (all P > 0.14). Adverse events were transient and not considered severe (e.g., gastrointestinal [GI] irritability, blood chemistry alterations). One participant was unable to tolerate persistent GI discomfort.

CONCLUSIONS

Long-term, high-dose DHA supplementation to patients with XLRP was associated with limited safety risks in this 4-year trial. Nevertheless, GI symptoms should be monitored in all patients taking high dose DHA especially those with personal or family history of GI disturbances. (ClinicalTrials.gov number, NCT00100230.).

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.

Clinical pharmacology of n-3 polyunsaturated fatty acids: non-lipidic metabolic and hemodynamic effects in human patients

A high dietary intake of n-3 long chain polyunsaturated fatty acids (PUFA), eicosapentaenoic and docosahexaenoic acids, is associated with a reduced incidence of coronary events. Supplementation with pharmacological doses of the same may improve survival in patients with previous myocardial infarction and established heart failure. Such protective effects may be explained by the action of n-3 PUFA on systemic inflammation, hypertension, endothelial dysfunction, thrombosis, cardiac arrhythmias, heart rate variability and atherosclerotic plaque instability, which are involved in the pathogenesis of these clinical conditions. In this short paper we will review the evidence in support of these pleiotropic effects of n-3 fatty acids.

Effect of stearidonic acid-enriched soybean oil on fatty acid profile and metabolic parameters in lean and obese Zucker rats

Background

Consumption of marine-based oils high in omega-3 polyunsaturated fatty acids (n3PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is known to protect against obesity-related pathologies. It is less clear whether traditional vegetable oils with high omega-6 polyunsaturated fatty acid (n6PUFA) content exhibit similar therapeutic benefits. As such, this study examined the metabolic effects of a plant-based n3PUFA, stearidonic acid (SDA), in polygenic obese rodents.

Methods

Lean (LZR) and obese Zucker (OZR) rats were provided either a standard westernized control diet (CON) with a high n6PUFA to n3PUFA ratio (i.e., 16.2/1.0) or experimental diet modified with flaxseed (FLAX), menhaden (FISH), or SDA oil that resulted in n6PUFA to n3PUFA ratios of 1.7/1.0, 1.3/1.0, and 1.0/0.8, respectively.

Results

After 12 weeks, total adiposity, dyslipidemia, glucose intolerance, and hepatic steatosis were all greater, whereas n3PUFA content in liver, adipose, and muscle was lower in OZR vs. LZR rats. Obese rodents fed modified FISH or SDA diets had lower serum lipids and hepatic fat content vs. CON. The omega-3 index (i.e., ΣEPA + DHA in erythrocyte membrane) was 4.0, 2.4, and 2.0-fold greater in rodents provided FISH, SDA, and FLAX vs. CON diet, irrespective of genotype. Total hepatic n3PUFA and DHA was highest in rats fed FISH, whereas both hepatic and extra-hepatic EPA was higher with FISH and SDA groups.

Conclusions

These data indicate that SDA oil represents a viable plant-derived source of n3PUFA, which has therapeutic implications for several obesity-related pathologies.

Genes involved in muscle lipid composition in 15 European Bos taurus breeds

Consumers demand healthy and palatable meat, both factors being affected by fat composition. However, red meat has relatively high concentration of saturated fatty acids and low concentration of the beneficial polyunsaturated fatty acids. To select animals prone to produce particular fat types, it is necessary to identify the genes influencing muscle lipid composition. This paper describes an association study in which a large panel of candidate genes involved in adipogenesis, lipid metabolism and energy homoeostasis was tested for effects on fat composition in 15 European cattle breeds. Sixteen genes were found to have significant effects on different lipid traits, and among these, CFL1 and MYOZ1 were found to have large effects on the ratio of 18:2/18:3, CRI1 on the amount of neutral adrenic acid (22:4 n-6), MMP1 on docosahexaenoic acid (22:6 n-3) and conjugated linoleic acid, PLTP on the ratio of n-6:n-3 and IGF2R on flavour. Several genes - ALDH2, CHRNE, CRHR2, DGAT1, IGFBP3, NEB, SOCS2, SUSP1, TCF12 and FOXO1 - also were found to be associated with both lipid and organoleptic traits although with smaller effect. The results presented here help in understanding the genetic and biochemical background underlying variations in fatty acid composition and flavour in beef.