High pancreatic n-3 fatty acids prevent STZ-induced diabetes in fat-1 mice: inflammatory pathway inhibition

Dietary menhaden fish oil supplementation suppresses lipopolysaccharide-induced neuroinflammation and cognitive impairment in diabetic rats

CONTEXT

Menhaden fish oil (FO) is widely recognized for inhibiting neuroinflammatory responses and preserving brain function. Nevertheless, the mechanisms of FO influencing brain cognitive function in diabetic states remain unclear.

OBJECTIVE

This study examines the potential role of FO in suppressing LPS-induced neuroinflammation and cognitive impairment in diabetic animals (DA).

MATERIALS AND METHODS

Thirty male Wistar rats were divided into 5 groups: i) DA received LPS induction (DA-LPS); ii) DA received LPS induction and 1 g/kg FO (DA-LPS-1FO); iii) DA received LPS induction and 3 g/kg FO (DA-LPS-3FO); iv) animals received normal saline and 3 g/kg FO (NS-3FO) and v) control animals received normal saline (CTRL). Y-maze test was used to measure cognitive performance, while brain samples were collected for inflammatory markers and morphological analysis.

RESULTS

DA received LPS induction, and 1 or 3 g/kg FO significantly inhibited hyperglycaemia and brain inflammation, as evidenced by lowered levels of pro-inflammatory mediators. Additionally, both DA-LPS-1FO and DA-LPS-3FO groups exhibited a notable reduction in neuronal damage and glial cell migration compared to the other groups. These results were correlated with the increasing number of entries and time spent in the novel arm of the Y-maze test.

DISCUSSION AND CONCLUSION

This study indicates that supplementation of menhaden FO inhibits the LPS signaling pathway and protects against neuroinflammation, consequently maintaining cognitive performance in diabetic animals. Thus, the current study suggested that fish oil may be effective as a supporting therapy option for diabetes to avoid diabetes-cognitive impairment.

The transplantation of the gut microbiome of fat-1 mice protects against colonic mucus layer disruption and endoplasmic reticulum stress induced by high fat diet

High-fat diets alter gut barrier integrity, leading to endotoxemia by impacting epithelial functions and inducing endoplasmic reticulum (ER) stress in intestinal secretory goblet cells. Indeed, ER stress, which is an important contributor to many chronic diseases such as obesity and obesity-related disorders, leads to altered synthesis and secretion of mucins that form the protective mucus barrier. In the present study, we investigated the relative contribution of omega-3 polyunsaturated fatty acid (PUFAs)-modified microbiota to alleviating alterations in intestinal mucus layer thickness and preserving gut barrier integrity. Male fat-1 transgenic mice (exhibiting endogenous omega-3 PUFAs tissue enrichment) and wild-type (WT) littermates were fed either an obesogenic high-fat diet (HFD) or a control diet. Unlike WT mice, HFD-fed fat-1 mice were protected against mucus layer alterations as well as an ER stress-mediated decrease in mucin expression. Moreover, cecal microbiota transferred from fat-1 to WT mice prevented changes in the colonic mucus layer mainly through colonic ER stress downregulation. These findings highlight a novel feature of the preventive effects of omega-3 fatty acids against intestinal permeability in obesity-related conditions.

Eicosapentaenoic acid metabolites promotes the trans-differentiation of pancreatic α cells to β cells

Type 1 diabetes mellitus (T1DM) is characterized by life-threatening absolute insulin deficiency. Although ω-3 polyunsaturated fatty acids (PUFAs) displayed significant anti-hyperglycemic activity, the insulinotropic effects of their metabolites remain unknown. In this study, we took advantage of a transgenic model, mfat-1, that overexpresses an ω-3 desaturase and can convert ω-6 PUFAs to ω-3 PUFAs. Eicosapentaenoic acid (EPA) was sharply elevated in the pancreatic tissues of mfat-1 transgenic mice compared with wild-type (WT) mice. In contrast to the WT mice, the mfat-1 transgenics did not develop overt diabetes and still maintained normal blood glucose levels and insulin secretion following streptozotocin-treatment. Furthermore, under the condition of pancreatic β-cell damage, co-incubation of the metabolites of EPA produced from the CYP 450 pathway with isolated islets promoted the overexpression of insulin as well as β-cell specific markers, pdx1 and Nkx6.1 in pancreatic α-cells. Addition of EPA metabolites to the cultured glucagon-positive α-cell lines, a series of pancreatic β-cell markers were also found significantly elevated. Combined together, these results demonstrated the effects of ω-3 PUFAs and their metabolites on the trans-differentiation from α-cells to β-cells and its potential usage in the intervention of T1DM.

n-3 Polyunsaturated Fatty Acids Modulate LPS-Induced ARDS and the Lung-Brain Axis of Communication in Wild-Type versus Fat-1 Mice Genetically Modified for Leukotriene B4 Receptor 1 or Chemerin Receptor 23 Knockout

Specialized pro-resolving mediators (SPMs) and especially Resolvin E1 (RvE1) can actively terminate inflammation and promote healing during lung diseases such as acute respiratory distress syndrome (ARDS). Although ARDS primarily affects the lung, many ARDS patients also develop neurocognitive impairments. To investigate the connection between the lung and brain during ARDS and the therapeutic potential of SPMs and its derivatives, fat-1 mice were crossbred with RvE1 receptor knockout mice. ARDS was induced in these mice by intratracheal application of lipopolysaccharide (LPS, 10 µg). Mice were sacrificed at 0 h, 4 h, 24 h, 72 h, and 120 h post inflammation, and effects on the lung, liver, and brain were assessed by RT-PCR, multiplex, immunohistochemistry, Western blot, and LC-MS/MS. Protein and mRNA analyses of the lung, liver, and hypothalamus revealed LPS-induced lung inflammation increased inflammatory signaling in the hypothalamus despite low signaling in the periphery. Neutrophil recruitment in different brain structures was determined by immunohistochemical staining. Overall, we showed that immune cell trafficking to the brain contributed to immune-to-brain communication during ARDS rather than cytokines. Deficiency in RvE1 receptors and enhanced omega-3 polyunsaturated fatty acid levels (fat-1 mice) affect lung-brain interaction during ARDS by altering profiles of several inflammatory and lipid mediators and glial activity markers.

Protective potential of fish oil supplementation against insulin resistance and pancreatic islet damage in STZ-induced Wistar rats

Background

Fish oil, which is regarded as the primary source of omega-3 fatty acids, has been long studied for its potential as an antidiabetic therapy. However, its protective ability against insulin resistance and pancreatic islet alteration remains unclear and controversial.

Aim

To investigate the beneficial effects of fish oil consumption on the progression of insulin resistance and pancreatic islet dysfunction in a rat model of diabetes.

Methods

Diabetic rats model (n = 30) were divided into five groups and received; 1) NS injection + NS oral (normal control); 2) NS injection + 3 g/kg fish oil (fish oil control); 3) streptozotocin (STZ) injection + NS oral [diabetes control (DC)]; 4) STZ injection + 1 g/kg fish oil (DFO1); and 5) STZ injection + 3 g/kg fish oil (DFO3). Fasting blood insulin was analyzed by commercial rat insulin enzyme-linked immunosorbent assay; meanwhile, the determination of insulin sensitivity was calculated by homeostatic model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of beta-cell function. A histological study was conducted on pancreas tissue using H and E staining.

Results

Fish oil supplementation reduced hyperglycemia and ameliorated HOMA-IR in STZ-induced animal models indicating that fish oil supplementation improved insulin sensitivity. Furthermore, animals treated with fish oil at a dose of 3 g/kg (DFO3) showed an enhancement in pancreatic islets, which was displayed by less abnormal structures than DC animals. This could imply that the administration of fish oil, especially rich in bioactive omega-3 fatty acids effectively inhibits insulin resistance and restore islet of Langerhans alteration in rats injected with STZ.

Conclusion

Thus, the current study suggested that fish oil supplementation could support the treatment of diabetes but should not be considered as an alternative therapy.

Effects of n-3 polyunsaturated fatty acid on metabolic status in women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials

This meta-analysis was conducted to summarize the effects of n-3 polyunsaturated fatty acid (n-3 PUFA) on metabolic status including insulin metabolism and lipid metabolism in women with polycystic ovary syndrome (PCOS) by randomized controlled trials (RCTs). Four mainstream databases including PubMed, Cochrane Library, Embase and Web of Science were searched from their inception to October 2021. The registration number of this study was CRD42021285233. The quality assessment was performed referring the Cochrane Risk of Bias Tool. Mean differences (MD) and 95% confidence intervals (CIs) were generated for continuous variables by meta-analysis. Subgroup analyses were performed based on study duration (≤ 8 weeks or > 8 weeks), the source of n-3 PUFA (marine derived or plant origins) and dosage of n-3 PUFA (≤ 1000 mg/d or > 1000 mg/d). Eventually, 11 RCTs reporting 816 patients were enrolled. Compared with control group, n-3 PUFA treatment decreased waist circumference (MD = -2.76, 95% CI: -3.82 to -1.69; p < 0.00001), fasting plasma glucose (MD = -3.91, 95% CI: -5.69 to -2.13; p < 0.0001), fasting insulin (MD = -2.45, 95% CI: -3.19 to -1.71; p < 0.00001), homeostatic model assessment of insulin resistance (MD = -0.45, 95% CI: -0.80 to -0.11; p = 0.01), triglyceride (MD = -9.33, 95% CI: -10.56 to -8.10; p < 0.00001), total cholesterol (MD = -12.32, 95% CI: -19.15 to -5.50; p = 0.0004), low-density lipoprotein cholesterol (MD = -10.53, 95% CI: -19.31 to -1.75; p = 0.02), and increase quantitative insulin sensitivity check index (MD = 0.01, 95% CI: 0.01 to 0.02; p < 0.00001), Adiponectin (MD = 1.46, 95% CI: 1.12 to 1.80; p < 0.00001) in PCOS patients. However, n-3 PUFA failed to change body weight, body mass index, high-density lipoprotein cholesterol, very low-density lipoprotein cholesterol and hs-CRP in the overall analysis. Further subgroup analyses showed that supplements of n-3 PUFA for more than 8 weeks is more conducive to improve the metabolic status in insulin resistance and lipid profiles. The meta-analysis demonstrates that n-3 PUFA may be an effective intervention for alleviating metabolic status in PCOS. Hence, we recommend PCOS patients replenish n-3 PUFA with duration > 8 weeks regardless of the source and the dosage to retard the pathogenesis of PCOS related metabolic diseases.

N-3 PUFA Deficiency Aggravates Streptozotocin-Induced Pancreatic Injury in Mice but Dietary Supplementation with DHA/EPA Protects the Pancreas via Suppressing Inflammation, Oxidative Stress and Apoptosis

It has been reported that dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) exert therapeutic potential for the preservation of functional β-cell mass. However, the effect of dietary n-3 PUFA deficiency on pancreatic injury and whether the supplementation of n-3 PUFA could prevent the development of pancreatic injury are still not clear. In the present study, an n-3 PUFA deficiency mouse model was established by feeding them with n-3 PUFA deficiency diets for 30 days. Results showed that n-3 PUFA deficiency aggravated streptozotocin (STZ)-induced pancreas injury by reducing the insulin level by 18.21% and the HOMA β-cell indices by 31.13% and the area of islet by 52.58% compared with the STZ group. Moreover, pre-intervention with DHA and EPA for 15 days could alleviate STZ-induced pancreas damage by increasing the insulin level by 55.26% and 44.33%, the HOMA β-cell indices by 118.81% and 157.26% and reversed the area of islet by 196.75% and 205.57% compared to the n-3 Def group, and the effects were significant compared to γ-linolenic acid (GLA) and alpha-linolenic acid (ALA) treatment. The possible underlying mechanisms indicated that EPA and DHA significantly reduced the ration of n-6 PUFA to n-3 PUFA and then inhibited oxidative stress, inflammation and islet β-cell apoptosis levels in pancreas tissue. The results might provide insights into the prevention and alleviation of pancreas injury by dietary intervention with PUFAs and provide a theoretical basis for their application in functional foods.

Age-related hearing loss was accelerated by apoptosis of spiral ganglion and stria vascularis cells in ApoE KO mice with hyperglycemia and hyperlipidemia

Age-related hearing loss (ARHL) is associated with diabetes and/or dyslipidemia in humans. However, the detailed mechanism for the development of ARHL by diabetes and/or dyslipidemia has not been elucidated. In this study, we investigated the etiology of ARHL in apolipoprotein E (ApoE)-deficient mice with diabetes and dyslipidemia. The atherosclerotic CD-STZ (mice fed with a control diet and received an STZ injection), WD-con (mice fed with a western diet), and WD-STZ (mice fed with a western diet and received an STZ injection) mice showed a 2.4-, 4.9-, and 6.8-fold larger area, respectively, occupied by lesions throughout the aorta compared with the CD-con mice. A significantly larger area under the curve (AUC) was observed in the STZ-treated groups than in the non-treated groups based on the oral glucose tolerance test (OGTT). At 20 weeks of age, HbA_1c levels were significantly higher in the CD-STZ and WD-STZ mice than in the CD-con and WD-con mice. In all the groups, the auditory brainstem response (ABR) thresholds of the 16-week-old mice were significantly higher compared with those of the 8-week-old mice. In particular, in the WD-STZ mice, the ABR thresholds of the left and right ears reached the maximum decibel peak equivalent sound pressure levels (130 dBpeSPL), which is a sign of deafness. The apoptotic spiral ganglion neurons (SGNs) of the WD-STZ mice were significantly increased compared with those of the other three groups, indicating that SGN apoptosis resulted in hearing loss in STZ-induced diabetic ApoE KO mice fed with a WD. A significant loss of the stria vascularis cells was observed in the WD-STZ group compared with the CD-con mice. In the organ of Corti, few apoptotic hair cells were found in all the groups; however, no significant difference was observed. Therefore, we consider that the reduced hearing ability in the STZ-treated and WD-fed groups was attributed to the damage to the SGN and stria vascularis in the cochlea. Thus, our results indicated that ototoxicity by diabetes and/or dyslipidemia accelerated ARHL in ApoE KO mice, thereby suggesting the importance of appropriate treatment of patients with diabetes and/or dyslipidemia to prevent ARHL.

Diet, Exercise, and the Metabolic Syndrome: Enrollment of the Mitochondrial Machinery

Metabolic syndrome (MS), a cluster of metabolic risk factors, ranging from abdominal obesity, dyslipidaemia, hypertension, type 2 diabetes and non-alcoholic fatty liver disease [...]

Lipid metabolism in type 1 diabetes mellitus: Pathogenetic and therapeutic implications

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease with insulin deficiency due to pancreatic β cell destruction. Multiple independent cohort studies revealed specific lipid spectrum alterations prior to islet autoimmunity in T1DM. Except for serving as building blocks for membrane biogenesis, accumulative evidence suggests lipids and their derivatives can also modulate different biological processes in the progression of T1DM, such as inflammation responses, immune attacks, and β cell vulnerability. However, the types of lipids are huge and majority of them have been largely unexplored in T1DM. In this review, based on the lipid classification system, we summarize the clinical evidence on dyslipidemia related to T1DM and elucidate the potential mechanisms by which they participate in regulating inflammation responses, modulating lymphocyte function and influencing β cell susceptibility to apoptosis and dysfunction. This review systematically recapitulates the role and mechanisms of various lipids in T1DM, providing new therapeutic approaches for T1DM from a nutritional perspective.

High Endogenously Synthesized N-3 Polyunsaturated Fatty Acids in Fat-1 Mice Attenuate High-Fat Diet-Induced Insulin Resistance by Inhibiting NLRP3 Inflammasome Activation via Akt/GSK-3β/TXNIP Pathway

High-fat (HF) diets and low-grade chronic inflammation contribute to the development of insulin resistance and type 2 diabetes (T2D), whereas n-3 polyunsaturated fatty acids (PUFAs), due to their anti-inflammatory effects, protect against insulin resistance. Interleukin (IL)-1β is implicated in insulin resistance, yet how n-3 PUFAs modulate IL-1β secretion and attenuate HF diet-induced insulin resistance remains elusive. In this study, a HF diet activated NLRP3 inflammasome via inducing reactive oxygen species (ROS) generation and promoted IL-1β production primarily from adipose tissue preadipocytes, but not from adipocytes and induced insulin resistance in wild type (WT) mice. Interestingly, endogenous synthesized n-3 polyunsaturated fatty acids (PUFAs) reversed this process in HF diet-fed fat-1 transgenic mice although the HF diet induced higher weight gain in fat-1 mice, compared with the control diet. Mechanistically, palmitic acid (PA), the main saturated fatty acid in an HF diet inactivated AMPK and led to decreased GSK-3β phosphorylation, at least partially through reducing Akt activity, which ultimately blocked the Nrf2/Trx1 antioxidant pathway and induced TXNIP cytoplasm translocation and NLRP3 inflammasome activation, whereas docosahexaenoic acid (DHA), the most abundant n-3 PUFA in fat-1 adipose tissue, reversed this process via inducing Akt activation. Our GSK-3β shRNA knockdown study further revealed that GSK-3β played a pivot role between the upstream AMPK/Akt pathway and downstream Nrf2/Trx1/TXNIP pathway. Given that NLRP3 inflammasome is implicated in the development of most inflammatory diseases, our results suggest the potential of n-3 PUFAs in the prevention or adjuvant treatment of NLRP3 inflammasome-driven diseases.

Syntaxin interacts with arachidonic acid to prevent diabetes mellitus

Syntaxin regulates pancreatic β cell mass and participates in insulin secretion by regulating insulin exocytosis. In addition, syntaxin 4 reduces IFNγ and TNF-α signaling via NF-ĸB in islet β-cells that facilitates plasma glucose sensing and appropriate insulin secretion. Arachidonic acid (AA) has potent anti-inflammatory actions and prevents the cytotoxic actions of alloxan and streptozotocin (STZ) against pancreatic β cells and thus, prevents the development of type 1 diabetes mellitus (induced by alloxan and STZ) and by virtue of its anti-inflammatory actions protects against the development of type 2 diabetes mellitus (DM) induced by STZ in experimental animals that are models of type 1 and type 2 DM in humans. AA has been shown to interact with syntaxin and thus, potentiate exocytosis. AA enhances cell membrane fluidity, increases the expression of GLUT and insulin receptors, and brings about its anti-inflammatory actions at least in part by enhancing the formation of its metabolite lipoxin A4 (LXA4). Prostaglandin E2 (PGE2), the pro-inflammatory metabolite of AA, activates ventromedial hypothalamus (VMH) neurons of the hypothalamus and inhibits insulin secretion leading to reduced glucose tolerance and decreases insulin sensitivity in the skeletal muscle and liver. This adverse action of PGE2 on insulin release and action can be attributed to its (PGE2) pro-inflammatory action and inhibitory action on vagal tone (vagus nerve and its principal neurotransmitter acetylcholine has potent anti-inflammatory actions). High fat diet fed animals have hypothalamic inflammation due to chronic elevation of PGE2. Patients with type 2 DM show low plasma concentrations of AA and LXA4 and elevated levels of PGE2. Administration of AA enhances LXA4 formation without altering or reducing PGE2 levels and thus, tilts the balance more towards anti-inflammatory events. These results suggest that administration of AA is useful in the prevention and management of DM by enhancing the action of syntaxin, increasing cell membrane fluidity, and reducing VMH inflammation. Docosahexaenoic acid (DHA) has actions like AA: it increases cell membrane fluidity; has anti-inflammatory actions by enhancing the formation of its anti-inflammatory metabolites resolvins, protectins and maresins; interacts with syntaxin and enhance exocytosis in general and of insulin. But the DHA content of cell membrane is lower compared to AA and its content in brain is significant. Hence, it is likely DHA is important in neurotransmitters secretion and regulating hypothalamic inflammation. It is likely that a combination of AA and DHA can prevent DM.

Effects of antioxidant intervention in patients with polycystic ovarian syndrome: A systematic review and meta-analysis

BACKGROUND

The role of antioxidant intervention in polycystic ovary syndrome (PCOS) patients has been increasingly investigated in recent years. In order to further clarify whether antioxidant therapy is beneficial for PCOS patients and the emphasis of its effects, this study provides a systematic review and meta-analysis of randomized controlled trials examining the effect of antioxidant intervention on PCOS.

METHODS

Enrolled study designs related to antioxidant interventions and PCOS, published from 1999 to 2020, were searched from EMBASE, PubMed, and Web of Science databases to sort out proven studies on antioxidant interventions and PCOS. Data were reported as weighted mean difference (WMD) or standard mean difference with associated confidence intervals of 95%. The analysis was conducted using Stata version 16.0.

RESULTS

Twenty-three studies were included in total. Antioxidant intervention had a positive impact on homeostasis model assessment of insulin resistance (WMD = -0.37, P = .011) and Triglycerides (WMD = -25.51, P < .001). And antioxidant intervention did not improve testosterone levels significantly (WMD = -0.20, P = .2611). Subgroup analysis showed that except for the D-chiro-inosito subgroup, no difference in body mass index was observed between the intervention group and the control group.

CONCLUSIONS

This meta-analysis demonstrates the efficacy of antioxidant intervention in patients with PCOS, demonstrating that antioxidant intervention has a significant effect on insulin resistance and lipid metabolism improvement. However, antioxidant intervention therapy has no discernible impact on testosterone levels or body mass index. Omega-3 may be a more effective antioxidant intervention for PCOS. In addition, this meta-analysis provides important reference opinions and treatment recommendations for PCOS.

Deuterium-Reinforced Polyunsaturated Fatty Acids Prevent Diet-Induced Nonalcoholic Steatohepatitis by Reducing Oxidative Stress

Background and Objectives: Oxidative stress is implicated in the progression of nonalcoholic steatohepatitis (NASH) through the triggering of inflammation. Deuterium-reinforced polyunsaturated fatty acids (D-PUFAs) are more resistant to the reactive oxygen species (ROS)-initiated chain reaction of lipid peroxidation than regular hydrogenated (H-) PUFAs. Here, we aimed to investigate the impacts of D-PUFAs on oxidative stress and its protective effect on NASH. Materials and Methods: C57BL/6 mice were randomly divided into three groups and were fed a normal chow diet, a methionine-choline-deficient (MCD) diet, and an MCD with 0.6% D-PUFAs for 5 weeks. The phenotypes of NASH in mice were determined. The levels of oxidative stress were examined both in vivo and in vitro. Results: The treatment with D-PUFAs attenuated the ROS production and enhanced the cell viability in tert-butyl hydroperoxide (TBHP)-loaded hepatocytes. Concurrently, D-PUFAs decreased the TBHP-induced oxidative stress in Raw 264.7 macrophages. Accordingly, D-PUFAs increased the cell viability and attenuated the lipopolysaccharide-stimulated proinflammatory cytokine expression of macrophages. In vivo, the administration of D-PUFAs reduced the phenotypes of NASH in MCD-fed mice. Specifically, D-PUFAs decreased the liver transaminase activity and attenuated the steatosis, inflammation, and fibrosis in the livers of NASH mice. Conclusion: D-PUFAs may be potential therapeutic agents to prevent NASH by broadly reducing oxidative stress.

NAG-1/GDF15 protects against streptozotocin-induced type 1 diabetes by inhibiting apoptosis, preserving beta-cell function, and suppressing inflammation in pancreatic islets

The loss of functional insulin-producing β-cells is a hallmark of type 1 diabetes mellitus (T1DM). Previously, we reported that the non-steroidal anti-inflammatory drug activated gene-1, or growth differentiation factor-15 (NAG-1/GDF15) inhibits obesity and improves insulin sensitivity in both genetic and dietary-induced obese mice. However, the regulatory role of NAG-1/GDF15 in the structure and function of β-cells and the prevention of T1DM is largely unknown. In the current study, we reported that NAG-1/GDF15 transgenic (Tg) mice are resistant to diabetogenesis induced by multiple low-dose streptozotocin (MLD-STZ) treatment. NAG-1/GDF15 overexpression significantly reduced diabetes incidence, alleviated symptoms of T1DM, and improved MLD-STZ-induced glucose intolerance and insulin resistance. Both the mass and function of pancreatic β cells were preserved in the NAG-1/GDF15 Tg mice as evidenced by significantly increased islet area and insulin production. The mechanistic study revealed that NAG-1/GDF15 significantly inhibited STZ-induced apoptosis and preserved the reduction of proliferation in the islets of the Tg mice as compared to the wild-type (WT) mice upon MLD-STZ treatment. Additionally, NAG-1/GDF15 significantly reduced both the serum and islet levels of the inflammatory cytokines (IL-1β, IL-6, and TNFα), and reduced the expression of NF-κB expression and immune cells infiltration in the islets. Collectively, these results indicate that NAG-1/GDF15 is effective in improving STZ-induced glucose intolerance, probably was mediated via suppressing inflammation, inhibiting apoptosis, and preserving β-cell mass and function.

Transplantation of Brown Adipose Tissue with the Ability of Converting Omega-6 to Omega-3 Polyunsaturated Fatty Acids Counteracts High-Fat-Induced Metabolic Abnormalities in Mice

A balanced omega (ω)-6/ω-3 polyunsaturated fatty acids (PUFAs) ratio has been linked to metabolic health and the prevention of chronic diseases. Brown adipose tissue (BAT) specializes in energy expenditure and secretes signaling molecules that regulate metabolism via inter-organ crosstalk. Recent studies have uncovered that BAT produces different PUFA species and circulating oxylipin levels are correlated with BAT-mediated energy expenditure in mice and humans. However, the impact of BAT ω-6/ω-3 PUFAs on metabolic phenotype has not been fully elucidated. The Fat-1 transgenic mice can convert ω-6 to ω-3 PUFAs. Here, we demonstrated that mice receiving Fat-1 BAT transplants displayed better glucose tolerance and higher energy expenditure. Expression of genes involved in thermogenesis and nutrient utilization was increased in the endogenous BAT of mice receiving Fat-1 BAT, suggesting that the transplants may activate recipients' BAT. Using targeted lipidomic analysis, we found that the levels of several ω-6 oxylipins were significantly reduced in the circulation of mice receiving Fat-1 BAT transplants than in mice with wild-type BAT transplants. The major altered oxylipins between the WT and Fat-1 BAT transplantation were ω-6 arachidonic acid-derived oxylipins via the lipoxygenase pathway. Taken together, these findings suggest an important role of BAT-derived oxylipins in combating obesity-related metabolic disorders.

Multistage Photoactivatable Zinc-Responsive Nanodevices for Monitoring and Regulating Dysfunctional Islet β-Cells

The dysfunctional islet β-cell triggered by excessive deposition of Zn²⁺ constituted a striking indicator of the occurrence of diabetic disease. However, it remained a formidable challenge to reflect the real-time function of β-cell by monitoring the Zn²⁺ content. Herein, multistage photoactivatable Zn²⁺-responsive nanodevice (denoted as AD2@USD1) was presented for sensing, regulating, and evaluating Zn²⁺ levels in dysfunctional islet β-cells. The photoactivated signatures on the satellite shell layer of the nanodevices and the internally loaded chelating factors effectively identified and intervened in the real-time concentration of Zn²⁺, the photothermal feedback component decorated on the inner core permitted the assessment of the post-intervention Zn²⁺ levels, achieving an integrated intervention and prognostic assessment in response to the abnormal islet β-cell function induced by Zn²⁺ deposition. In this way, one strategy for sensing and regulating islet β-cell function-oriented to Zn²⁺ was established. Our study introduced AD2@USD1 as a tool for effectively sensing, adjusting, and assessing the Zn²⁺ level in islet β-cells with abnormalities, gaining a potential breakthrough in the treatment of diabetes.

Vitamin D and Omega-3 Polyunsaturated Fatty Acids in Type 1 Diabetes modulation

BACKGROUND

Type 1 diabetes (T1D) is a chronic autoimmune disease that affects people globally. Usually developed during childhood, T1D is characterized by the destruction of pancreatic β-cells due to immune cell attack and the establishment of an inflammatory process.

OBJECTIVE

The study aimed to investigate the effects of vitamin D through its nuclear receptor and the ω-3 polyunsaturated fatty acids (PUFAs) through their lipid derivatives in T1D modulation. Both components exert anti-inflammatory activity and act directly on cells of the immune system, attenuating the destruction of insulin-producing cells. Furthermore, they lead to a better glycemic level, reducing the need for insulin and a normal immune state, such as C-peptide maintenance.

METHOD

Presently, our review highlights the significant studies that evaluated the supplementation of vitamin D and ω-3 PUFAs in humans and animal models in the modulation of T1D.

CONCLUSION

The data collected suggests that supplementation can provide potential benefits, mainly when done early in the diagnosis, since it reduces the need for insulin and the risk of complications generated by the disease.

The Ameliorative Impact of Centella asiatica on the Working Memory Deficit in Streptozotocin-induced Rat Model of Alzheimer Disease

Introduction

Alzheimer disease (AD) is a complex neurodegenerative disorder with a progressive nature leading to neural damage and cognitive and memory deficit. The present study investigated the neuroprotective effects of Centella asiatica (CA) in Streptozotocin (STZ)-induced rat model of memory impairment and neuronal damage.

Methods

The intracerebroventricular infusion of STZ (3 mg/rat) or saline (as the vehicle) was performed on days 1 and 3. CA (150 and 300 mg/kg/d) was administered through oral gavage for 21 days after model induction. We used the Y-maze test to assess the working memory-related performances of animals. Rats were then sacrificed, and their hippocampi were harvested for evaluation of neuronal density in the cornu ammonis (CA1, CA2, CA3) and Dentate Gyrus (DG) regions using stereology technique.

Results

The intracerebroventricular infusion of STZ caused significant working memory impairment demonstrated in the Y-maze apparatus, with a significant decrease in alternative behavior compared to control animals (40.67±2.04 vs 73.00±1.88, P<0.0001). Oral administration of CA (150 and 300 mg/kg each day) for 21 days significantly improved STZ-induced working memory deficit (55.33±3.34 and 57.17±3.81 vs 40.67±2.04, P<0.013, P<0.004, respectively). Furthermore, 21 days of consecutive administration of CA significantly ameliorated STZ-induced neuronal loss in the CA1, CA2, and DG subfields of the hippocampus.

Conclusion

Overall, these data demonstrate that CA increases neuronal density and improves cognitive impairment in the STZ-induced rat model of AD, thereby having promising therapeutic potential for neurodegenerative disorders. Accordingly, further studies are needed to determine the exact molecular mechanism of CA protective effects in brain disorders, particularly AD.

Highlights

Centella asiatica (CA) improved the STZ-induced working memory deficit.CA could prevent hippocampal neural cell loss dose-dependent manner.CA improved memory through mitigating neuronal loss in hippocampus.

Plain Language Summary

Memory loss is the first signs of dementia. It is well known that a healthy diet might be as good for your brain as it is for your heart. Numerous traditionally used medicinal herbs could significantly affect key events culminating in dementia and Alzheimer's disease. Centella asiatica, commonly known as Gotu Kola or Indian Pennywort, is a tropical, medicinal plant native to Southeast Asian countries. It is one of the becoming popular medicinal plants in the world. Centella asiatica (CA) is widely used in different traditional medicine systems for various purposes, such as reducing blood pressure, memory enhancement, and promoting longevity. In the present study, we tested the possible impact of CA leaf and stem extract in an animal model of memory damage. Memory impairment was induced in adult rats by intracerebral infusion of a neurotoxin chemical. Then, the memory-impaired animals were orally treated with 150-300 mg/kg of CA extract for 21 days. Finally, we tested their working memory by placing them in a Y-maze apparatus. Furthermore, their most involved brain part (hippocampus) was dissected, and its cell density was evaluated. Our findings exhibited that CA treatment considerably improved rats' memory performance, indicating by enhancing working memory score in the Y-maze task. In addition, CA treatment significantly prevented neuronal cell loss in the hippocampus of memory-impaired rats. This study shows that CA has beneficial effects on memory and cognitive function.

Insights in diabetes: Molecular mechanisms-Protectin DX, an anti-inflammatory and a stimulator of inflammation resolution metabolite of docosahexaenoic acid, protects against the development of streptozotocin-induced type 1 and type 2 diabetes mellitus in male Swiss albino mice

Our previous studies revealed that certain endogenous low molecular weight lipids have potent anti-diabetic actions. Of all, arachidonic acid (AA) and its anti-inflammatory and inflammation resolving metabolite lipoxin A4 (LXA4) are the most potent anti-diabetic molecules. Similar anti-diabetic action is also shown by resolvins. In our efforts to identify other similar lipid based anti-diabetic molecules, we investigated potential anti-diabetic action of protectin DX that also has anti-inflammatory and inducer of inflammation resolution action(s) like LXA4. Protectin DX {10(S),17(S)-dihydroxy-4Z,7Z,11E,13Z,15E,19Z-docosahexaenoic acid, also called as 10(S),17(S)-DiHDoHE)} prevented the development of streptozotocin-induced type 1 and type 2 diabetes mellitus in Swiss male albino mice. Protectin DX showed potent anti-inflammatory, antioxidant and anti-apoptotic actions that could explain its anti-diabetic action. In view of these beneficial actions, efforts need to be developed to exploit PDX and other similar compounds as potential anti-diabetic molecule in humans.

New Developments in T Cell Immunometabolism and Therapeutic Implications for Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease mediated by T cells and is becoming a serious public health threat. Despite the increasing incidence rate of T1D worldwide, our understanding of why T1D develops and how T cells lose their self-tolerance in this process remain limited. Recent advances in immunometabolism have shown that cellular metabolism plays a fundamental role in shaping T cell responses. T cell activation and proliferation are supported by metabolic reprogramming to meet the increased energy and biomass demand, and deregulation in immune metabolism can lead to autoimmune disorders. Specific metabolic pathways and factors have been investigated to rectify known deficiencies in several autoimmune diseases, including T1D. Most therapeutic strategies have concentrated on aerobic glycolysis to limit T cell responses, whereas glycolysis is the main metabolic pathway for T cell activation and proliferation. The use of metabolic inhibitors, especially glycolysis inhibitors may largely leave T cell function intact but primarily target those autoreactive T cells with hyperactivated metabolism. In this review, we provide an overview of metabolic reprogramming used by T cells, summarize the recent findings of key metabolic pathways and regulators modulating T cell homeostasis, differentiation, and function in the context of T1D, and discuss the opportunities for metabolic intervention to be employed to suppress autoreactive T cells and limit the progression of β-cell destruction.

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.

Essential Fatty Acids and Their Metabolites in the Pathobiology of Inflammation and Its Resolution

Arachidonic acid (AA) metabolism is critical in the initiation and resolution of inflammation. Prostaglandin E2 (PGE2) and leukotriene B4/D4/E4 (LTB4/LD4/LTE4), derived from AA, are involved in the initiation of inflammation and regulation of immune response, hematopoiesis, and M1 (pro-inflammatory) macrophage facilitation. Paradoxically, PGE2 suppresses interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production and triggers the production of lipoxin A4 (LXA4) from AA to initiate inflammation resolution process and augment regeneration of tissues. LXA4 suppresses PGE2 and LTs' synthesis and action and facilitates M2 macrophage generation to resolve inflammation. AA inactivates enveloped viruses including SARS-CoV-2. Macrophages, NK cells, T cells, and other immunocytes release AA and other bioactive lipids to produce their anti-microbial actions. AA, PGE2, and LXA4 have cytoprotective actions, regulate nitric oxide generation, and are critical to maintain cell shape and control cell motility and phagocytosis, and inflammation, immunity, and anti-microbial actions. Hence, it is proposed that AA plays a crucial role in the pathobiology of ischemia/reperfusion injury, sepsis, COVID-19, and other critical illnesses, implying that its (AA) administration may be of significant benefit in the prevention and amelioration of these diseases.

Molecular biochemical aspects of salt (sodium chloride) in inflammation and immune response with reference to hypertension and type 2 diabetes mellitus

Obesity, insulin resistance, type 2 diabetes mellitus (T2DM) and hypertension (HTN) are common that are associated with low-grade systemic inflammation. Diet, genetic factors, inflammation, and immunocytes and their cytokines play a role in their pathobiology. But the exact role of sodium, potassium, magnesium and other minerals, trace elements and vitamins in the pathogenesis of HTN and T2DM is not known. Recent studies showed that sodium and potassium can modulate oxidative stress, inflammation, alter the autonomic nervous system and induce dysfunction of the innate and adaptive immune responses in addition to their action on renin-angiotensin-aldosterone system. These actions of sodium, potassium and magnesium and other minerals, trace elements and vitamins are likely to be secondary to their action on pro-inflammatory cytokines IL-6, TNF-α and IL-17 and metabolism of essential fatty acids that may account for their involvement in the pathobiology of insulin resistance, T2DM, HTN and autoimmune diseases.

Chronic n-3 fatty acid intake enhances insulin response to oral glucose and elevates GLP-1 in high-fat diet-fed obese mice

n-3 polyunsaturated fatty acids (PUFA) can exert beneficial effects on glucose homeostasis, especially in obese rodents. Gut incretin hormones regulate glucose and lipid homeostasis, but their involvement in the above effects is not entirely clear. This study aims to assess the effects of chronic n-3 PUFA administration on the insulin and incretin responses in C57BL/6N obese male mice subjected to oral glucose tolerance test (oGTT) after 8 weeks of feeding a corn-oil-based high-fat diet (cHF). The weight gain and adiposity were partially reduced in mice fed cHF in which some of the corn oil was replaced with n-3 PUFA concentrate containing ∼60% DHA and EPA in a 3 : 1 ratio. In addition, these mice had improved glucose tolerance, which was consistent with an increased insulin response to oral glucose and plasma glucagon-like peptide-1 (GLP-1) levels. While the stimulatory effects of n-3 PUFA on GLP-1 levels could not be attributed to changes in intestinal or plasma dipeptidyl peptidase-4 activity, their beneficial effects on glucose tolerance were abolished when mice were pretreated with the GLP-1 receptor antagonist exendin 9-39. Moreover, chronic n-3 PUFA intake prevented the detrimental effects of cHF feeding on glucose-stimulated insulin secretion in the pancreatic islets. Collectively, our data suggest that n-3 PUFA may modulate postprandial glucose metabolism in obese mice through a GLP-1-based mechanism. The significance of these findings in terms of the effective DHA and EPA ratio of the n-3 PUFA concentrate as well as the effect of n-3 PUFA in humans requires further research.

Interaction Between GAD65 Antibodies and Dietary Fish Intake or Plasma Phospholipid n-3 Polyunsaturated Fatty Acids on Incident Adult-Onset Diabetes: The EPIC-InterAct Study

OBJECTIVE

Islet autoimmunity is associated with diabetes incidence. We investigated whether there was an interaction between dietary fish intake or plasma phospholipid n-3 polyunsaturated fatty acid (PUFA) concentration with the 65-kDa isoform of GAD (GAD65) antibody positivity on the risk of developing adult-onset diabetes.

RESEARCH DESIGN AND METHODS

We used prospective data on 11,247 incident cases of adult-onset diabetes and 14,288 noncases from the EPIC-InterAct case-cohort study conducted in eight European countries. Baseline plasma samples were analyzed for GAD65 antibodies and phospholipid n-3 PUFAs. Adjusted hazard ratios (HRs) for incident diabetes in relation to GAD65 antibody status and tertiles of plasma phospholipid n-3 PUFA or fish intake were estimated using Prentice-weighted Cox regression. Additive (proportion attributable to interaction [AP]) and multiplicative interactions between GAD65 antibody positivity (≥65 units/mL) and low fish/n-3 PUFA were assessed.

RESULTS

The hazard of diabetes in antibody-positive individuals with low intake of total and fatty fish, respectively, was significantly elevated (HR 2.52 [95% CI 1.76-3.63] and 2.48 [1.79-3.45]) compared with people who were GAD65 antibody negative and had high fish intake, with evidence of additive (AP 0.44 [95% CI 0.16-0.72] and 0.48 [0.24-0.72]) and multiplicative (P = 0.0465 and 0.0103) interactions. Individuals with high GAD65 antibody levels (≥167.5 units/mL) and low total plasma phospholipid n-3 PUFAs had a more than fourfold higher hazard of diabetes (HR 4.26 [2.70-6.72]) and an AP of 0.46 (0.12-0.80) compared with antibody-negative individuals with high n-3 PUFAs.

CONCLUSIONS

High fish intake or relative plasma phospholipid n-3 PUFA concentrations may partially counteract the increased diabetes risk conferred by GAD65 antibody positivity.

High n-3 fatty acids counteract hyperglycemia-induced insulin resistance in fat-1 mice via pre-adipocyte NLRP3 inflammasome inhibition

Although n-3 polyunsaturated fatty acids (n-3 PUFAs) have potential anti-insulin resistance activity, the mechanism remains largely unknown. In this study, increased glucose resistance, insulin sensitivity, and lower glycemia were observed upon streptozotocin (STZ) treatment in n-3 PUFA-enriched fat-1 mice compared to wild type (WT) mice. Endogenous n-3 PUFAs in fat-1 mice were found to impair hyperglycemia or high glucose level-induced nucleotide-binding domain and leucine-rich repeat pyrin 3 domain (NLRP3) inflammasome activation and inhibit IL-1β secretion in adipose tissues. In addition, endogenous n-3 PUFAs also inhibited high glucose-induced caspase-1 activity and IL-1β secretion in pre-adipocyte-enriched stromal vascular fractions (SVF) isolated from adipose tissues. Furthermore, in 3T3-L1 pre-adipocytes, high levels of glucose induced thioredoxin interacting protein (TXNIP) expression and activated the NLRP3 inflammasome, which was counteracted by docosahexaenoic acid (DHA), the major n-3 PUFA in fat-1 mice, by downregulating TXNIP via the phosphatidylinositol-3-kinase (PI3K)/Akt pathway. Our results suggest that n-3 PUFA-mediated insulin sensitivity is at least partly associated with inflammasome inhibition in pre-adipocytes. Our findings highlight the potential clinical use of dietary n-3 PUFAs in the prevention or intervention of T2D and other NLRP3 inflammasome-driven inflammatory diseases.

Omega-3 Fatty Acids Effects on Inflammatory Biomarkers and Lipid Profiles among Diabetic and Cardiovascular Disease Patients: A Systematic Review and Meta-Analysis

The purpose of this systematic review and meta-analysis was to investigate omega-3 fatty acids’ influence on 12 inflammatory biomarkers—LDL, HDL, total cholesterol, TG, HbA1c, Apo AI, Apo AII, Apo B, CRP, TNF-α, glucose, and fasting blood glucose among diabetic and cardiovascular disease (CVD) patients. We searched articles in six database engines, and 16 of the 696 articles reviewed met the inclusion criteria. Among these, lipid and inflammatory biomarkers investigated commonly included total cholesterol (11 studies), LDL, and TG (10 studies each). Overall, omega-3 was associated with a significant reduction in Apo AII among diabetic patients, as compared to different controls (−8.0 mg/dL 95% CI: −12.71, −3.29, p = 0.0009), triglycerides (−44.88 mg/dL 95% CI: −82.6, −7.16, p < 0.0001), HDL (−2.27 mg/dL 95% CI: −3.72, −0.83, p = 0.002), and increased fasting blood glucose (16.14 mg/dL 95% CI: 6.25, 26.04, p = 0.001). Omega-3 also was associated with increased LDL among CVD patients (2.10 mg/dL 95% CI: 1.00, 3.20, p = 0.0002). We conclude that omega-3 fatty acids may be associated with lower inflammatory biomarkers among diabetic and cardiovascular patients. Clinicians should be aware of these potential benefits; however, it is essential to recommend that patients consult with clinicians before any omega-3 intake.

Alteration of adipose tissue immune cell milieu towards the suppression of inflammation in high fat diet fed mice by flaxseed oil supplementation

The present study evaluates the effect of flaxseed oil (FXO) supplementation on adipose tissue macrophages (ATM’s), E and D series resolvin (Rv) levels and adipose tissue inflammation. Male C57BL/6J mice were divided into five groups (n = 5): lean group (given standard chow diet), HFD group given high fat diet (approx. 18 weeks) till they developed insulin resistance and 4, 8 or 16 mg/kg group (HFD group later orally supplemented with 4, 8 or 16 mg/kg body weight flaxseed oil) for 4 weeks.The present study showed that FXO supplementation led to enhanced DHA, EPA, RvE1-E2, RvD2, RvD5- D6, IL-4, IL-10 and arginase 1 levels in ATMs together with altered immune cell infiltration and reduced NF-κB expression. The FXO supplementation suppresses immune cell infiltration into adipose tissue and alters adipose tissue macrophage phenotype towards the anti-inflammatory state via enhancement of E and D series resolvins, arginase 1 expression and anti-inflammatory cytokines level (IL-4 and IL-10.) leading to amelioration of insulin resistance in flaxseed oil supplemented HFD mice.

Therapeutic Potential of ω-3 Polyunsaturated Fatty Acids in Human Autoimmune Diseases

The recognition of ω-3 polyunsaturated acids (PUFAs) as essential fatty acids to normal growth and health was realized more than 80 years ago. However, the awareness of the long-term nutritional intake of ω-3 PUFAs in lowering the risk of a variety of chronic human diseases has grown exponentially only since the 1980s (1, 2). Despite the overwhelming epidemiological evidence, many attempts of using fish-oil supplementation to intervene human diseases have generated conflicting and often ambiguous outcomes; null or weak supporting conclusions were sometimes derived in the subsequent META analysis. Different dosages, as well as the sources of fish-oil, may have contributed to the conflicting outcomes of intervention carried out at different clinics. However, over the past decade, mounting evidence generated from genetic mouse models and clinical studies has shed new light on the functions and the underlying mechanisms of ω-3 PUFAs and their metabolites in the prevention and treatment of rheumatoid arthritis, systemic lupus erythematosus (SLE), multiple sclerosis, and type 1 diabetes. In this review, we have summarized the current understanding of the effects as well as the underlying mechanisms of ω-3 PUFAs on autoimmune diseases.

Endogenous n-3 Polyunsaturated Fatty Acids Are Beneficial to Dampen CD8+ T Cell-Mediated Inflammatory Response upon the Viral Infection in Mice

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) have been known to exert anti-inflammatory effects on various disease states. However, its effect on CD8⁺ T cell-mediated immunopathology upon viral infection has not been well elucidated yet. In this study, we investigated the possible implication of n-3 PUFAs in CD8⁺ T cell responses against an acute viral infection. Infection of FAT-1 transgenic mice that are capable of synthesizing n-3 PUFAs from n-6 PUFAs with lymphocytic choriomeningitis virus (LCMV) resulted in significant reduction of anti-viral CD8⁺ T cell responses. Interestingly, expansion of adoptively transferred wild-type (WT) LCMV-specific T cell receptor (TCR) transgenic CD8⁺ (P14) T cells into FAT-1 mice was significantly decreased. Also, activation of anti-viral CD4⁺ helper T cells was reduced in FAT-1 mice. Importantly, P14 cells carrying the fat-1 gene that were adoptively transferred into WT mice exhibited a substantially decreased ability to proliferate and produce cytokines against LCMV infection. Together, n-3 PUFAs attenuated anti-viral CD8⁺ T cell responses against an acute viral infection and thus could be used to alleviate immunopathology mediated by the viral infection.

Effects of Flaxseed Oil Omega-3 Fatty Acids Supplementation on Regression and Metabolic Status in Endometrial Hyperplasia: A randomized, Double-Blind, Placebo-Controlled Trial

Background:

Data on the effects of omega-3 fatty acid supplementation on clinical symptoms and metabolic profiles in patients with endometrial hyperplasia (EH) are limited. This intervention was performed to assess the effects of omega-3 fatty acid supplementation on clinical symptoms and metabolic profiles in patients with endometrial hyperplasia (EH).

Methods:

This randomized, double-blind, placebo-controlled trial was conducted among 40 women diagnosed with simple endometrial hyperplasia (EH). EH diagnosis was performed based on specific diagnostic procedures of biopsy. Participants were randomised into two groups to intake 1,000 mg omega-3 fatty acid supplements from flaxseed oil (n = 20) or placebo (n = 20), twice a day for 12 weeks. Fasting blood samples were taken at baseline and after the 12-week intervention to determine related markers.

Results:

Compared with the placebo, omega-3 fatty acid supplementation significantly decreased fasting plasma glucose (FPG) (-7.1 ± 9.6 vs. +2.0 ± 4.9 mg/dL, P = 0.001), serum insulin levels (-1.5 ± 4.6 vs. +1.6 ± 3.9 μIU/mL, P = 0.02) and homeostasis model of assessment-insulin resistance (HOMA-IR) (-0.4 ± 1.1 vs. +0.4 ± 1.0, P = 0.02). In addition, a significant increase in plasma total antioxidant capacity (TAC) (+102.6 ± 69.6 vs. +5.0 ± 37.1 mmol/L, P < 0.001) and total glutathione (GSH) levels (+63.6 ± 84.9 vs. -3.0 ± 69.4 μmol/L, P = 0.01) were seen following the supplementation of omega-3 fatty acid compared with the placebo. Omega-3 fatty acid supplementation had no significant effect on regression, lipid profiles, and other biomarkers of inflammation and oxidative.

Conclusions:

In conclusion, we found that omega-3 fatty acid administration for 12 weeks to subjects with EH significantly improved FPG, insulin, HOMA-IR, TAC and GSH levels, but did not influence regression, lipid profiles, and other biomarkers of inflammatory and oxidative stress.

The efficacy of omega-3 fatty acid for gestational diabetes: a meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of omega-3 fatty acid to treat gestational diabetes remains controversial. We conduct a systematic review and meta-analysis to explore the influence of omega-3 fatty acid versus placebo on gestational diabetes.

METHODS

We search PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through March 2018 for randomized controlled trials (RCTs) assessing the effect of omega-3 fatty acid versus placebo on gestational diabetes. This meta-analysis is performed using the random-effect model.

RESULTS

Five RCTs are included in the meta-analysis. Overall, compared with control group for gestational diabetes, omega-3 fatty acid can significantly reduce fasting plasma glucose (FPG) (mean difference (MD) = -4.91; 95% confidence interval (CI) = -8.16 to -1.66; p = .003), homeostatic model of assessment for insulin resistance (HOMA-IR, MD = -0.99; 95% CI = -1.61 to -0.37; p = .002), high sensitivity C-reactive protein (hs-CRP, MD = -1.43; 95% CI = -2.54 to -0.31; p = .01), but has no remarkable influence on preterm delivery (RR = 1.61; 95% CI = 0.36-7.16; p = .53), gestational age (MD = 0.09; 95% CI = -0.01 to 0.20; p = .08), macrosomia (RR = 0.64; 95% CI = 0.26-1.62; p = .3), newborn weight (MD = 3.37; 95% CI = -15.75 to 22.50; p = .73), and 5-min Apgar score (MD = 0; 95% CI = -0.02 to 0.02; p = .92).

CONCLUSIONS

Omega-3 fatty acids is associated with significantly reduced FPG, HOMA-IR, and hs-CRP in patients with gestational diabetes.

n-3 Polyunsaturated fatty acids for the management of alcoholic liver disease: A critical review

Excess alcohol exposure leads to alcoholic liver disease (ALD), a predominant cause of liver-related morbidity and mortality worldwide. In the past decade, increasing attention has been paid to understand the association between n-3 polyunsaturated fatty acids (n-3 PUFAs) and ALD. In this review, we summarize the metabolism of n-3 PUFAs, animal model of ALD, and the findings from recent studies determining the role of n-3 PUFAs in ALD as a possible treatment. The animal models of acute ethanol exposure, chronic ethanol exposure and chronic-plus-single binge ethanol feeding have been widely used to explore the impact of n-3 PUFAs. Although the results of studies regarding the role of n-3 PUFAs in ALD have been inconsistent or controversial, increasing evidence has demonstrated that n-3 PUFAs may be useful in alleviating alcoholic steatosis and alcohol-induced liver injury through multiple mechanisms, including decreased de novo lipogenesis and lipid mobilization from adipose tissue, enhanced mitochondrial fatty acid β-oxidation, reduced hepatic inflammation and oxidative stress, and promoted intestinal homeostasis, positively suggesting that n-3 PUFAs might be promising for the management of ALD. The oxidation of n-3 PUFAs ex vivo in an experimental diet was rarely considered in most n-3 PUFA-related studies, likely contributing to the inconsistent results. Thus, the role of n-3 PUFAs in ALD deserves greater research efforts and remains to be evaluated in randomized, placebo-controlled clinic trial. ABBREVIATION AA arachidonic acid ACC acetyl-CoA carboxylase ACLY ATP-citrate lyase ACO acyl-CoA oxidase ALA α-linolenic acid ALD alcoholic liver disease ALP alkaline phosphatase ALT alanine aminotransferase AMPK AMP-activated protein kinase AST aspartate aminotransferase ATGL adipose triglyceride lipase cAMP cyclic adenosine 3',5'-monophosphate COX cyclooxygenases CPT1 carnitine palmitoyltransferase 1 CYP2E1 cytochrome P450 2E1 DGAT2 diacylglycerol acyltransferase 2 DGLA dihomo-γ-linolenic acid DHA docosahexaenoic acid DPA docosapentaenoic acid DTA docosatetraenoic acid EPA eicosapentaenoic acid ER endoplasmic reticulum ETA eicosatetraenoic acid FAS fatty acid synthase FATPs fatty acid transporter proteins GLA,γ linolenic acid GPR120 G protein-coupled receptor 120 GSH glutathione; H&E haematoxylin-eosin; HO-1 heme oxygenase-1; HSL hormone-sensitive lipase; IL-6 interleukin-6 iNOS nitric oxide synthase LA linoleic acid LBP lipopolysaccharide binding protein LOX lipoxygenases LXR liver X receptor LXREs LXR response elements MCP-1 monocyte chemotactic protein-1 MTP microsomal triglyceride transfer protein MUFA monounsaturated fatty acids MyD88 myeloid differentiation factor 88 n-3 PUFAs omega-3 polyunsaturated fatty acid NAFLD nonalcoholic fatty liver disease NASH nonalcoholic steatohepatitis NF-κB transcription factor nuclear factor κB PDE3B phosphodiesterase 3B PPAR peroxisome proliferator-activated receptor ROS reactive oxygen species RXR retinoid X receptor SCD-1 stearyl CoA desaturase-1 SDA stearidonic acid SFA saturated fatty acids SIRT1 sirtuin 1 SOD superoxide dismutase SREBP sterol regulatory element-binding protein TB total bilirubin TC total cholesterol TG triacylglycerol TLR4 Toll-like receptor-4 TNF-α tumor necrosis factor-α VLDLR very low-density lipoprotein receptor WT wild type; ZO-1 zonula occludens-1.

The effects of fish oil omega-3 fatty acid supplementation on mental health parameters and metabolic status of patients with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

This study was conducted to evaluate the effects of fish oil omega-3 fatty acid supplementation on mental health parameters and metabolic status of women with polycystic ovary syndrome (PCOS).

METHODS

This randomized double-blind, placebo-controlled trial was conducted on 60 women with PCOS, aged 18-40 years old. Participants were randomly assigned into two groups to receive either 2 × 1000 mg/day fish oil omega-3 fatty acid (n = 30) or placebo (n = 30) after lunch for 12 weeks. Metabolic profiles were quantified at baseline and after the 12-week intervention.

RESULTS

Compared with the placebo, omega-3 fatty acid intake led to a significant improvement in Beck Depression Inventory [β (difference in the mean outcomes measures between treatment groups after intervention) -1.05; 95% CI: -1.84, -0.26; p = .01], general health questionnaire (β -1.68; 95% CI: -3.12, -0.24; p = .02) and depression anxiety and stress scale (β -2.03; 95% CI: -3.60, -0.46; p = .01). Omega-3 fatty acid supplementation significantly decreased serum insulin levels (β -2.09 µIU/mL; 95% CI: -3.77, -0.41; p = .01), homeostasis model of assessment-insulin resistance (β -0.74; 95% CI: -1.13, -0.34; p < .001), total testosterone (β -0.23 ng/mL; 95% CI: -0.39, -0.06; p = .03) and hirsutism (β -0.75; 95% CI: -1.17, -0.33; p = .001), and significantly increased the quantitative insulin sensitivity check index (β 0.01; 95% CI: 0.003, 0.02; p = .008) compared with the placebo. Additionally, omega-3 fatty acid intake resulted in a significant decrease in high sensitivity C-reactive protein (β -1.46 mg/L; 95% CI: -2.16, -0.75; p < .001) and malondialdehyde (β -0.28 µmol/L; 95% CI: -0.52, -0.05; p = .03); also significant rises in plasma total glutathione (β 59.09 µmol/L; 95% CI: 7.07, 111.11; p = .02) was observed compared with the placebo. Omega-3 fatty acid supplementation did not change other metabolic parameters.

CONCLUSION

Overall, omega-3 fatty acid supplementation for 12 weeks to patients with PCOS had beneficial effects on mental health parameters, insulin metabolism, total testosterone, hirsutism and few inflammatory markers and oxidative stress.

High-dose ω-3 Fatty Acid Plus Vitamin D3 Supplementation Affects Clinical Symptoms and Metabolic Status of Patients with Multiple Sclerosis: A Randomized Controlled Clinical Trial

Background

Combined omega-3 fatty acid and vitamin D supplementation may improve multiple sclerosis (MS) by correcting metabolic abnormalities and attenuating oxidative stress and inflammation.

Objective

This study aimed to determine the effects of ω-3 fatty acid and vitamin D cosupplementation on the disability score and metabolic status of patients with MS.

Methods

This was a randomized, placebo-controlled clinical trial with Expanded Disability Status Scale (EDSS) score and inflammation as primary outcomes and oxidative stress biomarkers and metabolic profile as secondary outcomes. Patients, aged 18-55 y, were matched for disease EDSS scores, gender, medications, BMI, and age (n = 53) and randomly received a combined 2 × 1000 mg/d ω-3 fatty acid and 50,000 IU/biweekly cholecalciferol supplement or placebo for 12 wk. The placebos were matched in colour, shape, size, packaging, smell, and taste with supplements. Fasting blood samples were collected at baseline and end of intervention to measure different outcomes. Multiple linear regression models were used to assess treatment effects on outcomes adjusting for confounding variables.

Results

Patients taking ω-3 fatty acid plus vitamin D supplements showed a significant improvement in EDSS (β -0.18; 95% CI: -0.33, -0.04; P = 0.01), compared with placebo. Serum high-sensitivity C-reactive protein (β -1.70 mg/L; 95% CI: -2.49, -0.90 mg/L; P < 0.001), plasma total antioxidant capacity (β +55.4 mmol/L; 95% CI: 9.2, 101.6 mmol/L; P = 0.02), total glutathione (β +51.14 µmol/L; 95% CI: 14.42, 87.87 µmol/L; P = 0.007), and malondialdehyde concentrations (β -0.86 µmol/L; 95% CI: -1.10, -0.63 µmol/L; P < 0.001) were significantly improved in the supplemented group compared with the placebo group. In addition, ω-3 fatty acid and vitamin D cosupplementation resulted in a significant reduction in serum insulin, insulin resistance, and total/HDL-cholesterol, and a significant increase in insulin sensitivity and serum HDL-cholesterol concentrations.

Conclusion

Overall, taking ω-3 fatty acid and vitamin D supplements for 12 wk by patients with MS had beneficial effects on EDSS and metabolic status. This trial was registered at the Iranian website (www.irct.ir) for registration of clinical trials as IRCT2017090133941N20.

The Transplantation of ω3 PUFA-Altered Gut Microbiota of fat-1 Mice to Wild-Type Littermates Prevents Obesity and Associated Metabolic Disorders

Altering the gut microbiome may be beneficial to the host and recently arose as a promising strategy to manage obesity. Here, we investigated the relative contribution of ω3 polyunsaturated fatty acid (PUFA)-mediated alterations in the microbiota to metabolic parameter changes in mice. Four groups were compared: male fat-1 transgenic mice (with constitutive production of ω3 PUFAs) and male wild-type (WT) littermates fed an obesogenic (high fat/high sucrose [HFHS]) or a control diet. Unlike WT mice, HFHS-fed fat-1 mice were protected against obesity, glucose intolerance, and hepatic steatosis. Unlike WT mice, fat-1 mice maintained a normal barrier function, resulting in a significantly lower metabolic endotoxemia. The fat-1 mice displayed greater phylogenic diversity in the cecum, and fecal microbiota transplantation from fat-1 to WT mice was able to reverse weight gain and to normalize glucose tolerance and intestinal permeability. We concluded that the ω3 PUFA-mediated alteration of gut microbiota contributed to the prevention of metabolic syndrome in fat-1 mice. It occurred independently of changes in the PUFA content of host tissues and may represent a promising strategy to prevent metabolic disease and preserve a lean phenotype.

Suppression of Postprandial Blood Glucose Fluctuations by a Low-Carbohydrate, High-Protein, and High-Omega-3 Diet via Inhibition of Gluconeogenesis

Hyperglycemia significantly contributes to the development and progression of metabolic diseases. Managing postprandial blood glucose fluctuations is of particular importance for patients with hyperglycemia, but safe and effective means of reducing blood glucose levels are still lacking. Five diets with varying macronutrient ratios and omega-3 fatty acid amounts were tested for their blood glucose-lowering effects in male C57BL/6J mice. The diets with potent blood glucose-lowering effects were further investigated for their underlying mechanisms and their beneficial effects on hyperglycemia models. Mice given the low-carbohydrate, high-protein, and high-omega-3 (LCHP+3) diet exhibited a rapid reduction of the blood glucose levels that remained consistently low, regardless of feeding. These effects were associated with reduced amino acid gluconeogenesis, due to the inhibition of hepatic alanine transaminase (ALT). Furthermore, the LCHP+3 intervention was effective in reducing the blood glucose levels in several disease conditions, including type 1 diabetes mellitus, hormone-induced hyperglycemia, and diet-induced metabolic syndrome. Our findings identify the LCHP+3 diet as a potent blood glucose-lowering diet that suppresses postprandial blood glucose fluctuations through the inhibition of gluconeogenesis and may have great clinical utility for the management of metabolic diseases with hyperglycemia.

Bisphenol A and octylphenol exacerbate type 1 diabetes mellitus by disrupting calcium homeostasis in mouse pancreas

In pancreatic β cells, which produce and secrete insulin, Ca²⁺ signals contribute to insulin production and secretion. Bisphenol A (BPA) and octylphenol (OP) are reported to increase plasma insulin levels and insulin transcription factors, but regulation of plasma glucose levels did not decrease proportionally to the insulin increase. We hypothesized that BPA and OP disrupt calcium homeostasis resulting in insulin resistance through induction of endoplasmic reticulum (ER) stress. BPA and OP treatment leads to survival of pancreatic β cells against streptozotocin, but despite an increased insulin level, serum glucose regulation is not properly regulated. The expression of genes involved in transporting calcium ions to the cytosol and ER decreased while the expression of those affecting the removal of calcium from the cytosol and ER increased. Depletion of calcium from the ER leads to ER stress and can induce insulin resistance. Insulin resistance is also confirmed by insulin-responsive gene, such as glucose transporter 4 (GLUT4) and IRS2, expression. Taken together, these results imply that disruption of calcium homeostasis by BPA and OP induces ER stress and leads to insulin resistance, especially in a streptozotocin (STZ) -induced type 1 diabetes mellitus model.

Hepatic Lipogenesis and Brain Fatty Acid Profile in Response to Different Dietary n6/n3 Ratios and DHA/EPA Supplementation in Streptozotocin Treated Rats

SCOPE

We investigated the interaction between streptozotocin (STZ)-induced diabetes and dietary n6/n3 ratio, and its influence on lipogenesis.

METHODS AND RESULTS

The animals were treated with STZ and fed with different dietary n6/n3 ratios: 1, 7, and 60, or supplemented with DHA/EPA. Gene expression was assessed by RT-PCR and protein expression by western blotting and immunohistochemistry. Fatty acid profile was determined by GC-MS. Pancreas and liver histology were assessed by hematoxylin and eosin (H&E) staining. STZ-induced characteristic changes in all STZ treated groups, including: increased blood glucose, decreased body mass, increased lipid peroxidation and CD36 expression, decreased 16:1n7 and 18:1n7, increases in 20:3n6, decreases in phospholipid (PL) content of 20:4n6, as well as decreases in the expression of SREBP1c, Δ-9-desaturase (Δ9D), and Δ-5-desaturase (Δ5D). Additionally, other changes occurred that were dependent on the n6/n3 ratio. Among the diabetic groups, the lower n6/n3 ratio caused higher lipid peroxidation and CD36 expression, a greater decrease in 20:4n6 and decreased Δ6-desaturase (Δ6D) expression, while the higher n6/n3 ratio caused increased partitioning of 20:4n6 into hepatic neutral lipids (NL), a decrease in 20:5n3 content, and increased β-oxidation.

CONCLUSION

Presented data suggest that the n6/n3 ratio could significantly influence lipogenesis, lipid peroxidation, and β-oxidation in STZ-induced diabetes, which could have clinical significance.

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.

Effect of human umbilical cord blood-derived mononuclear cells on diabetic nephropathy in rats

Diabetic nephropathy (DN) is damage to the kidney which can lead to chronic renal failure, eventually requiring dialysis. Diabetes mellitus is the most common cause of adult kidney failure worldwide in the developed world. The current work was designed to elucidate the effect of mononuclear cells (MNCs) injection on reverse DN in rats exposed to streptozotocin (STZ) injection compared to metformin as a known hypoglycemic drug, 40 Male rats were divided equally into 4 groups; normal control group, diabetic control group, MNCs group were diabetic rats treated with MNCs (30×10⁶ MNCs/rat once iv dose) in the tail vein of the rat, and metformin group were diabetic rats treated with metformin (100mg/kg orally daily dose) for four weeks. The results indicated an improvement effect of MNCs and metformin on STZ-induced DN in rats, which was evidenced by significant decrease in urinary albumin/creatinine ratio, N-acetyl-β-d-glucosaminidase (NAG), urinary kidney injury molecule-1 (KIM-1), serum urea, serum creatinine and fasting blood glucose and significant increase in C- peptide level, compared to diabetic control group. Additionally MNCs treated group exhibited pronounced effects in all previous parameters compared to metformin treated group. It is proved that MNCs treatment was superior to metformin in controlling hyperglycemia, and improving renal function in diabetic rats.

The Effects of Flaxseed Oil Omega-3 Fatty Acids Supplementation on Metabolic Status of Patients with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective This study was conducted to evaluate the effects of flaxseed oil omega-3 fatty acids supplementation on metabolic status of patients with polycystic ovary syndrome (PCOS).

Methods This randomized double-blind, placebo-controlled trial was conducted on 60 women with PCOS according to the Rotterdam criteria aged 18–40 years old. Participants were randomly assigned into two groups to receive either 1,000 mg flaxseed oil omega-3 fatty acids (n=30) or placebo (n=30) twice a day for 12 weeks. Metabolic, endocrine, inflammatory factors were quantified at baseline and after the 12-week intervention.

Results After the 12-week intervention, compared to the placebo, flaxseed oil omega-3 supplementation significantly decreased insulin values (−2.6±7.7 vs.+1.3±3.9 µIU/mL, P=0.01), homeostasis model of assessment-estimated insulin resistance (−0.7±1.7 vs.+0.3±0.9, P=0.01), mF-G scores (−1.2±1.7 vs. -0.1±0.4, P=0.001), and increased quantitative insulin sensitivity check index (+0.01±0.02 vs. −0.01±0.02, P=0.01). In addition, supplementation with flaxseed oil omega-3 resulted in significant decreases in serum triglycerides (−5.1±20.9 vs.+9.7±26.1 mg/dL, P=0.01), VLDL-cholesterol (−1.0±4.2 vs.+1.9±5.2 mg/dL, P=0.01) and high-sensitivity C-reactive protein (hs-CRP) (−1.6±3.1 vs.+0.2±1.5 mg/L, P=0.004) compared to the placebo. We did not see any significant effect of flaxseed oil omega-3 supplementation on hormonal and other lipid profiles, and plasma nitric oxide levels.

Conclusions Overall, flaxseed oil omega-3 supplementation for 12 weeks in women with PCOS had beneficial effects on insulin metabolism, mF-G scores, serum triglycerides, VLDL-cholesterol and hs-CRP levels, but did not affect hormonal and other lipid profiles, and plasma nitric oxide levels.

Modulation of the endogenous omega-3 fatty acid and oxylipin profile in vivo-A comparison of the fat-1 transgenic mouse with C57BL/6 wildtype mice on an omega-3 fatty acid enriched diet

Dietary intervention and genetic fat-1 mice are two models for the investigation of effects associated with omega-3 polyunsaturated fatty acids (n3-PUFA). In order to assess their power to modulate the fatty acid and oxylipin pattern, we thoroughly compared fat-1 and wild-type C57BL/6 mice on a sunflower oil diet with wild-type mice on the same diet enriched with 1% EPA and 1% DHA for 0, 7, 14, 30 and 45 days. Feeding led after 14–30 days to a high steady state of n3-PUFA in all tissues at the expense of n6-PUFAs. Levels of n3-PUFA achieved by feeding were higher compared to fat-1 mice, particularly for EPA (max. 1.7% in whole blood of fat-1 vs. 7.8% following feeding). Changes in PUFAs were reflected in most oxylipins in plasma, brain and colon: Compared to wild-type mice on a standard diet, arachidonic acid metabolites were overall decreased while EPA and DHA oxylipins increased with feeding more than in fat-1 mice. In plasma of n3-PUFA fed animals, EPA and DHA metabolites from the lipoxygenase and cytochrome P450 pathways dominated over ARA derived counterparts.Fat-1 mice show n3-PUFA level which can be reached by dietary interventions, supporting the applicability of this model in n3-PUFA research. However, for specific questions, e.g. the role of EPA derived mediators or concentration dependent effects of (individual) PUFA, feeding studies are necessary.