Fenofibrate ameliorates diabetic and dyslipidemic profiles in KKAy mice partly via down-regulation of 11β-HSD1, PEPCK and DGAT2

A comparative study of the hypolipidemic effects and mechanisms of action of Laminaria japonica- and Ascophyllum nodosum-derived fucoidans in apolipoprotein E-deficient mice

The structural characteristics of fucoidans exhibit species and regional diversity. Previous studies have demonstrated that Laminaria japonica- and Ascophyllum nodosum-derived fucoidans have type I and type II fucosyl chains, respectively. These chemical differences may contribute to distinct hypolipidemic effects and mechanisms of action. Chemical analysis demonstrated that the percentage contents of sulfate, glucuronic acid, and galactose were higher in L. japonica-derived fucoidans than those of A. nodosum-derived fucoidans. In hyperlipidemic apolipoprotein E-deficient mice, both A. nodosum- and L. japonica-derived fucoidans significantly decreased the plasma and hepatic levels of total cholesterol and triglyceride, leading to the reduction of atherosclerotic plaques. Western blotting experiments demonstrated that these fucoidans significantly enhanced the expression and levels of scavenger receptor B type 1, cholesterol 7 alpha-hydroxylase A1, and peroxisome proliferator-activated receptor (PPAR)-α, contributing to circulating lipoprotein clearance and fatty acid degradation, respectively. Differentially, L. japonica-derived fucoidan significantly increased the LXR/ATP-binding cassette G8 signaling pathway in the small intestine, as revealed by real-time quantitative PCR, which may lead to further cholesterol and other lipid excretion. Collectively, these data are useful for understanding the hypolipidemic mechanisms of action of seaweed-derived fucoidans, and their potential application for the prevention and/or treatment of atherosclerotic cardiovascular diseases.

Long-Term Fenofibrate Treatment Stimulates the Phenotypic Microevolution of Prostate Cancer Cells In Vitro

Fenofibrate is a widely used anti-hyperlipidemic agonist of peroxisome proliferator-activated receptor alpha (PPARα). As a metabolic blocker, fenofibrate interferes with cancer promotion/progression via its misbalancing effects on cellular metabolism. However, the consequences of its long-term application for patients with diagnosed drug-resistant cancers are unknown. We addressed this point by tracing the phenotypic microevolution of naïve and drug-resistant prostate cancer PC3_DCX20 cells that underwent a long-term exposition to 10 μM and 50 μM fenofibrate. Their resistance to fenofibrate, metabolic profile and invasive phenotype were estimated in the control conditions and under fenofibrate-induced stress. Apparently, drug efflux systems are not effective against the cytostatic FF action. However, wtPC3 and PC3_DCX20 cells that survived the long-term 50 μM fenofibrate treatment gave rise to lineages that displayed an increased proliferation rate, lower motility in the control conditions and enhanced fenofibrate resistance. Attenuated fenofibrate bioavailability modified the pattern of PC3 microevolution, as illustrated by phenotypic differences between wtPC3/PC3_DCX20 lineages propagated in the presence of 50 μM and 10 μM fenofibrate. Collectively, our observations indicate that fenofibrate acts as a selective factor that affects prostate cancer microevolution. We also pinpoint potential consequences of long-term exposition of prostate cancer patients to metabolic blockers.

Interactions between nuclear receptors glucocorticoid receptor α and peroxisome proliferator-activated receptor α form a negative feedback loop

Both nuclear receptors glucocorticoid receptor α (GRα) and peroxisome proliferator-activated receptor α (PPARα) are involved in energy and lipid metabolism, and possess anti-inflammation effects. Previous studies indicate that a regulatory loop may exist between them. In vivo and in vitro studies showed that glucocorticoids stimulate hepatic PPARα expression via GRα at the transcriptional level. This stimulation of PPARα by GRα has physiological relevance and PPARα is involved in many glucocorticoid-induced pathophysiological processes, including gluconeogenesis and ketogenesis during fasting, insulin resistance, hypertension and anti-inflammatory effects. PPARα also synergizes with GRα to promote erythroid progenitor self-renewal. As the feedback, PPARα inhibits glucocorticoid actions at pre-receptor and receptor levels. PPARα decreases glucocorticoid production through inhibiting the expression and activity of type-1 11β-hydroxysteroid dehydrogenase, which converts inactive glucocorticoids to active glucocorticoids at local tissues, and also down-regulates hepatic GRα expression, thus forming a complete and negative feedback loop. This negative feedback loop sheds light on prospective multi-drug therapeutic treatments in inflammatory diseases through a combination of glucocorticoids and PPARα agonists. This combination may potentially enhance the anti-inflammatory effects while alleviating side effects on glucose and lipid metabolism due to GRα activation. More investigations are needed to clarify the underlying mechanism and the relevant physiological or pathological significance of this regulatory loop.

Pharmacodynamic and pharmacokinetic interaction of losartan with glimepiride-metformin combination in rats and rabbits

OBJECTIVES:

The presence of comorbidities such as cardiovascular disease, peripheral vascular disease, and chronic renal disease, or and the prevention of these ailments in diabetics, frequently demands multiple drug treatments, increasing the risk of drug-drug interactions (DDIs). The current study was focused on identifying possible DDIs on concomitant administration of losartan, a drug used to regulate hypertension along with a combination of glimepiride + metformin, widely used to treat diabetes mellitus. Possible pharmacodynamic and pharmacokinetic interactions were observed for, following single-dose as well as multiple-dose treatment protocols in normal and alloxan-induced diabetes in albino Wistar rats and rabbits.

MATERIALS AND METHODS:

Blood samples from surviving rats/rabbits obtained through orbital venous sinus bleeding/marginal ear vein bleeding, respectively, at predetermined intervals and put through to biochemical estimations of sugar level in the blood by Glucose oxidase/peroxidase method; insulin levels in serum using the enzyme-linked immunosorbent assay and serum glimepiride levels using the high-performance liquid chromatography.

RESULTS AND DISCUSSION:

Losartan, when treated as a single drug, resulted in a slight lowering of blood glucose levels in normal rats, diabetic rats and normal rabbits. Hypoglycemic activity of a combination of glimepiride + metformin was enhanced when losartan was co-administered as a single dosage schedule as well as a multiple dose schedule as indicated by a reduced blood glucose level and enhanced levels of insulin in rats as well as in rabbits. Serum glimepiride levels were also higher and pharmacokinetic parameters of glimepiride including mean residence time, C_max, T_1/2, AUMC_0-∞, AUMC_0-t, and AUC_0-∞, were significantly higher, whereas its clearance was decreased in the two regimens of losartan that was followed.

CONCLUSION:

It can therefore be concluded, that in diabetics with hypertension as a comorbidity condition, co-administration of losartan with glimepiride + metformin should be avoided or the dosage of a combination of glimepiride + metformin needs to be tittered to avoid recurrence of hypoglycemic episodes.

Discovery of analogues of non-β oxidizable long-chain dicarboxylic fatty acids as dual inhibitors of fatty acids and cholesterol synthesis: Efficacy of lead compound in hyperlipidemic hamsters reveals novel mechanism

BACKGROUND AND AIMS

Cholesterol and triglycerides are risk factors for developing cardiovascular disease. Therefore, appropriate cells and assays are required to discover and develop dual cholesterol and fatty acid inhibitors. A predictive hyperlipidemic animal model is needed to evaluate mechanism of action of lead molecule for therapeutic indications.

METHODS AND RESULTS

Primary hepatocytes from rat, hamster, rabbit, and humans were compared for suitability to screen compounds by de novo lipogenesis (DNL) using14C-acetate. Hyperlipidemic hamsters were used to evaluate efficacy and mode of action. In rat hepatocytes DNL assay, both the central moiety and carbon chain length influenced the potency of lipogenesis inhibition. In hyperlipidemic hamsters, ETC-1002 decreased plasma cholesterol and triglycerides by 41% and 49% at the 30 mg/kg dose. Concomitant decreases in non-esterified fatty acids (-34%) and increases in ketone bodies (20%) were associated with induction of hepatic CPT1-α. Reductions in proatherogenic VLDL-C and LDL-C (-71% and -64%) occurred partly through down-regulation of DGAT2 and up-regulation of LPL and PDK4. Activation of PLIN1 and PDK4 dampened adipogenesis and showed inverse correlation with adipose mass. Hepatic concentrations of cholesteryl ester and TG decreased by 67% and 64%, respectively. Body weight decreased with concomitant decreases in epididymal fat. Plasma and liver concentrations of ETC-1002 agreed with the observed dose-response efficacy.

CONCLUSIONS

Taken together, ETC-1002 reduced proatherogenic lipoproteins, hepatic lipids and adipose tissues in hyperlipidemic hamsters via induction of LPL, CPT1-α, PDK4, and PLIN1, and downregulation of DGAT2. These characteristics may be useful in the treatment of fatty livers that causes non-alcoholic steatohepatitis.

Fenofibrate, a peroxisome proliferator-activated receptor-alpha agonist, blocks steatosis and alters the inflammatory response in a mouse model of inflammation-dioxin interaction

2,3,7,8-Tetrachlorodibenzo-p-dioxin (dioxin; TCDD) is an environmental contaminant that elicits a variety of toxic effects, many of which are mediated through activation of the aryl hydrocarbon receptor (AhR). Interaction between AhR and the peroxisome proliferator-activated receptor-alpha (PPAR-α), which regulates fatty acid metabolism, has been suggested. Furthermore, with recognition of the prevalence of inflammatory conditions, there is current interest in the potential for inflammatory stress to modulate the response to environmental agents. The aim of this work was to assess the interaction of TCDD with hepatic inflammation modulated by fenofibrate, a PPAR-α agonist. Female, C57BL/6 mice were treated orally with vehicle or fenofibrate (250 mg/kg) for 13 days, and then were given vehicle or 30 μg/kg TCDD. Four days later, the animals received an i.p. injection of lipopolysaccharide-galactosamine (LPS-GalN) (0.05x10⁷ EU/kg and 500 mg/kg, respectively) to incite inflammation, or saline as vehicle control. After 4 h, the mice were euthanized, and blood and liver samples were collected for analysis. Livers of animals treated with TCDD with or without LPS-GalN had increased lipid deposition, and this effect was blocked by fenofibrate. In TCDD/LPS-GalN-treated mice, fenofibrate caused an increase in plasma activity of alanine aminotransferase, a marker of hepatocellular injury. TCDD reduced LPS-GalN-induced apoptosis, an effect that was prevented by fenofibrate pretreatment. LPS-GalN induced an increase in the concentration of interleukin-6 in plasma and accumulation of neutrophils in liver. TCDD exposure enhanced the former response and inhibited the latter one. These results suggest that fenofibrate counteracts the changes in lipid metabolism induced by TCDD but increases inflammation and liver injury in this model of inflammation-TCDD interaction.

Effects of dietary phytol on tissue accumulation of phytanic acid and pristanic acid and on the tissue lipid profiles in mice

Recent in vitro evidence suggests that the phytol-derived fatty acids, phytanic acid (PA) and pristanic acid (PrA), are components of animal products with the potential to cause both beneficial and harmful effects on human health. In this study, we investigated the in vivo tissue accumulation of PA and PrA and the changes in tissue lipid profiles, using mice fed a phytol-containing diet. After 4 weeks of treatment with a diet containing 1.0% phytol, plasma, adipose tissue, liver, and brain were collected and their lipid profiles were biochemically and gas-chromatographically determined. Dietary phytol caused PA and PrA accumulation in the adipose tissue and liver but not in the brain, and reduced plasma and liver triacylglycerol levels. Phytol intake also decreased the fatty acid concentrations in the adipose tissue, especially polyunsaturated fatty acids such as linoleic acid, but increased the concentrations of these fatty acids in the liver. However, dietary phytol had a low impact on the brain lipid profile. This study suggests that dietary phytol intake caused accumulation of PA and PrA and modified lipid profiles in the adipose tissue and liver, but that the brain is an insusceptible tissue to dietary phytol-induced changes.

Lemon Balm Extract ALS-L1023 Regulates Obesity and Improves Insulin Sensitivity via Activation of Hepatic PPARα in High-Fat Diet-Fed Obese C57BL/6J Mice

Our previous studies demonstrated that peroxisome proliferator-activated receptor α (PPARα) activation reduces weight gain and improves insulin sensitivity in obese mice. Since excess lipid accumulation in non-adipose tissues is suggested to be responsible for the development of insulin resistance, this study was undertaken to examine whether the lemon balm extract ALS-L1023 regulates hepatic lipid accumulation, obesity, and insulin resistance and to determine whether its mechanism of action involves PPARα. Administration of ALS-L1023 to high-fat-diet-induced obese mice caused reductions in body weight gain, visceral fat mass, and visceral adipocyte size without changes of food consumption profiles. ALS-L1023 improved hyperglycemia, hyperinsulinemia, glucose and insulin tolerance, and normalized insulin-positive β-cell area in obese mice. ALS-L1023 decreased hepatic lipid accumulation and concomitantly increased the expression of PPARα target genes responsible for fatty acid β-oxidation in livers. In accordance with the in vivo data, ALS-L1023 reduced lipid accumulation and stimulated PPARα reporter gene expression in HepG2 cells. These effects of ALS-L1023 were comparable to those of the PPARα ligand fenofibrate, while the PPARα antagonist GW6471 inhibited the actions of ALS-L1023 on lipid accumulation and PPARα luciferase activity in HepG2 cells. Higher phosphorylated protein kinase B (pAkt)/Akt ratios and lower expression of gluconeogenesis genes were observed in the livers of ALS-L1023-treated mice. These results indicate that ALS-L1023 may inhibit obesity and improve insulin sensitivity in part through inhibition of hepatic lipid accumulation via hepatic PPARα activation.

Peripheral circadian rhythms in the liver and white adipose tissue of mice are attenuated by constant light and restored by time-restricted feeding

Disturbance of circadian rhythms underlies various metabolic diseases. Constant light exposure (LL) is known to disrupt both central and peripheral circadian rhythms. Here, we attempted to determine whether the effects of LL are different between various peripheral tissues and whether time-restricted feeding restores the circadian rhythms especially in white adipose tissue (WAT). Six-week-old mice were subjected to three feeding regimes: ad libitum feeding under light/dark phase (LD), ad libitum feeding under LL cycle, and restricted feeding at night-time under LL cycle with a normal chow. After 3 weeks, we compared body weight, food intake, plasma levels of lipids and glucose, and the expression patterns of the clock genes and the genes involved in lipid metabolism in the liver and WAT. The mice kept under LL with or without time-restricted feeding were 5.2% heavier (p<0.001, n = 16) than the mice kept under LD even though the food intakes of the two groups were the same. Food intake occurred mostly in the dark phase. LL disrupted this pattern, causing disruptions in circadian rhythms of plasma levels of triglycerides (TG) and glucose. Time-restricted feeding partially restored the rhythms. LL eliminated the circadian rhythms of the expression of the clock genes as well as most of the genes involved in lipid metabolism in both liver and WAT. More notably, LL markedly decreased not only the amplitude but also the average levels of the expression of the genes in the liver, but not in the WAT, suggesting that transcription in the liver is sensitive to constant light exposure. Time-restricted feeding restored the circadian rhythms of most of the genes to various degrees in both liver and WAT. In conclusion, LL disrupted the peripheral circadian rhythms more severely in liver than in WAT. Time-restricted feeding restored the circadian rhythms in both tissues.

Comparative Evaluation of Gemcabene and Peroxisome Proliferator-Activated Receptor Ligands in Transcriptional Assays of Peroxisome Proliferator-Activated Receptors: Implication for the Treatment of Hyperlipidemia and Cardiovascular Disease

Gemcabene, a late-stage clinical candidate, has shown efficacy for LDL-C, non-HDL cholesterol, apoB, triglycerides, and hsCRP reduction, all risk factors for cardiovascular disease. In rodents, gemcabene showed changes in targets, including apoC-III, apoA-I, peroxisomal enzymes, considered regulated through peroxisome proliferator-activated receptor (PPAR) gene activation, suggesting a PPAR-mediated mechanism of action for the observed hypolipidemic effects observed in rodents and humans. In the current study, the gemcabene agonist activity against PPAR subtypes of human, rat, and mouse were compared with known lipid lowering PPAR activators. Surprisingly, gemcabene showed no or little PPAR-α transactivation compared with reference agonists, which showed concentration-dependent transactivation against human PPAR-α of 2.4- to 30-fold (fenofibric acid), 17-fold (GW590735), and 2.3- to 25-fold (WY-14643). These agents also showed robust transactivation of mouse and rat PPAR-α in a concentration-dependent manner. The known PPAR-δ agonists, GW1516, L165041, and GW0742, showed potent agonist activity against human, mouse, and rat receptors (ranging from 165- to 396-fold). By contrast, gemcabene at the highest concentration tested (300 μM) showed no response in mouse and rat and a marginal response against human PPAR-δ receptors (3.2-fold). For PPAR-γ, gemcabene showed no agonist activity against all 3 species at 100 μM and marginal activity (3.6- to 5-fold) at 300 μM. By contrast, the known agonists, rosiglitazone, indomethacin, and muraglitazar showed strong activation against the mouse, rat, and human PPAR-γ receptors. No clear antagonist activity was observed with gemcabene against any PPAR subtypes for all 3 species over a wide range of concentrations. In summary, the transactivation studies rule out gemcabene as a direct agonist or antagonist of PPAR-α, PPAR-γ, and PPAR-δ receptors of these 3 species. These data suggest that the peroxisomal effects observed in rodents and the lipid regulating effects observed in rodents and humans are not related to a direct activation of PPAR receptors by gemcabene.

Lack of Correlation of Plasma HDL With Fecal Cholesterol and Plasma Cholesterol Efflux Capacity Suggests Importance of HDL Functionality in Attenuation of Atherosclerosis

A number of clinical findings suggested HDL-raising as a plausible approach to treat residual risk of CVD. However, lack of CVD risk reduction by elevated HDL cholesterol (HDL-C) through cholesterol ester transfer protein (CETP) inhibition and enhanced risk reduction in apolipoprotein A-I Milano (apoAI-M) individuals with low HDL-C shifted the focus from HDL-C level to HDL function. In the present study, we investigated correlations between HDL-C, HDL function, fecal cholesterol excretion, and ex vivo plasma cholesterol efflux capacity (CEC) in animal models using two HDL modulators, LXR and PPAR-α agonists. In C57Bl mice, LXR agonist, T1317, raised HDL-C by 30%, while PPAR-α agonist, fenofibrate, reduced HDL-C by 30%, but fecal cholesterol showed twofold increase in both cases. CEC showed a 30–40% increase. Combination of LXR and PPAR-α agonists showed no changes in HDL-C, but, interestingly, fecal cholesterol increased by 4.5-fold, and CEC by 40%, suggesting existence of additional pathway for fecal cholesterol excretion. Regression analysis showed a lack of correlation between HDL-C and fecal cholesterol and CEC, while fecal cholesterol showed significant correlation with CEC, a measure of HDL function. ABCA1 and G1, the two important players in RCT showed greater induction with LXR agonist than PPAR-α agonist. HDL-C increased by 40 and 80% in LXR and PPAR-α treated apoA-I transgenic mice, respectively, with 80% increase in fecal cholesterol. A fivefold increase in fecal cholesterol with no correlation with either plasma HDL-C or CEC following co-treatment with LXR and PPAR-α agonists suggested existence of an HDL-independent pathway for body cholesterol elimination. In hyperlipidemic diabetic ob/ob mice also combination of LXR and PPAR-α agonists showed marked increases in fecal cholesterol content (10–20-fold), while HDL-C rise was only 40%, further suggesting HDL-independent elimination of body cholesterol in mice treated with combination of LXR and PPAR-α agonists. Atherosclerosis attenuation by LXR and PPAR-α agonists in LDLr-deficient mice was associated with increased fecal cholesterol, but not HDL-C. However, fecal cholesterol counts showed inverse correlation with aortic cholesteryl ester content. These data suggest: (a) lack of correlation between HDL-C and fecal or aortic cholesterol content; (b) HDL function (CEC) correlated with fecal cholesterol content; (c) association of reduced aortic lipids in LDLr^−/− mice with increased fecal cholesterol, but not with HDL-C, and (d) existence of an HDL-independent pathway for fecal cholesterol excretion following co-treatment with LXR and PPAR-α agonists.

Anticancer Properties of Fenofibrate: A Repurposing Use

Cancer is a leading cause of death throughout the world, and cancer therapy remains a big medical challenge in terms of both its therapeutic efficacy and safety. Therefore, to find out a safe anticancer drug has been long goal for oncologist and medical scientists. Among clinically used medicines with no or little toxicity, fenofibrate is a drug of the fibrate class that plays an important role in lowering the levels of serum cholesterol and triglycerides while elevating the levels of high-density lipoproteins. Recently, several studies have implied that fenofibrate may exert anticancer effects via a variety of pathways involved in apoptosis, cell-cycle arrest, invasion, and migration. Given the great potential that fenofibrate may have anticancer effects, this review was to investigate all published works which directly or indirectly support the anticancer activity of fenofibrate. These studies provide evidence that fenofibrate exerted antitumor effects in several human cancer cell lines, such as breast, liver, glioma, prostate, pancreas, and lung cancer cell lines. Among these studies some have further confirmed the possibility and efficacy of fenofibrate anticancer in xenograft mouse models. In the last part of this review, we also discuss the potential mechanisms of action of fenofibrate based on the available information. Overall, we may repurpose fenofibrate as an anticancer drug in cancer treatment, which urgently need further and comprehensively investigated.

Fenofibrate reverses changes induced by high-fat diet on metabolism in mice muscle and visceral adipocytes

The effect of fenofibrate on the metabolism of skeletal muscle and visceral white adipose tissue of diet-induced obese (DIO) mice was investigated. C57BL/6J male mice were fed either a control or high-fat diet for 8 weeks. Fenofibrate (50 mg/Kg BW, daily) was administered by oral gavage during the last two weeks of the experimental period. Insulin-stimulated glucose metabolism in soleus muscles, glucose tolerance test, insulin tolerance test, indirect calorimetry, lipolysis of visceral white adipose tissue, expression of miR-103-3p in adipose tissue, and miR-1a, miR-133a/b, miR-206, let7b-5p, miR-23b-3p, miR-29-3p, miR-143-3p in soleus muscle, genes related to glucose and fatty acid metabolism in adipose tissue and soleus muscle, and proteins (phospho-AMPKα2, Pgc1α, Cpt1b), intramuscular lipid staining, and activities of fatty acid oxidation enzymes in skeletal muscle were investigated. In DIO mice, fenofibrate prevented weight gain induced by HFD feeding by increasing energy expenditure; improved whole body glucose homeostasis, and in skeletal muscle, increased insulin dependent glucose uptake, miR-1a levels, reduced intramuscular lipid accumulation, and phospho-AMPKα2 levels. In visceral adipose tissue of obese mice, fenofibrate decreased basal lipolysis rate and visceral adipocytes hypertrophy, and induced the expression of Glut-4, Irs1, and Cav-1 mRNA and miR-103-3p suggesting a higher insulin sensitivity of the adipocytes. The evidence is presented herein that beneficial effects of fenofibrate on body weight, glucose homeostasis, and muscle metabolism might be related to its action in adipose tissue. Moreover, fenofibrate regulates miR-1a-3p in soleus and miR-103-3p in adipose tissue, suggesting these microRNAs might contribute to fenofibrate beneficial effects on metabolism.

AMPK-dependent signaling modulates the suppression of invasion and migration by fenofibrate in CAL 27 oral cancer cells through NF-κB pathway

Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist and lipid-lowering agent, has been used worldwide for treatment of hyperlipidemia. The clinical trials demonstrate that fenofibrate possesses multiple pharmacological activities, including antitumor effects. However, the precise mechanisms in oral squamous cell carcinoma (OSCC) remain unclear. In this study, we investigated the anticancer effects of fenofibrate on the migration and invasion of human oral cancer CAL 27 cells. Fenofibrate inhibited the cell migration and invasion of CAL 27 cells by the wound healing and Boyden chamber transwell assays, respectively. In addition, fenofibrate reduced the protein expressions of MMP-1, MMP-2, MMP-7, and MMP-9 by Western blotting and inhibited enzyme activities of MMP-2/-9 using gelatin zymography assay. Results from immunoblotting analysis showed that the proteins of p-LKB1 (Ser428), LKB1, p-AMPKα (Thr172), p-AMPKα1/α2 (Ser425/Ser491), p-AMPKβ1 (Ser108), and AMPKγ1 were upregulated by fenofibrate; the levels of p-IKKα/β (Ser176) and p-IκBα were reduced in fenofibrate-treated cells. Also, fenofibrate suppressed the expressions of nuclear NF-κB p65 and p50 by immunoblotting and NF-κB DNA binding activity by EMSA assay. The anti-invasive effect of fenofibrate was attenuated by compound C [an adenosine 5'-monophosphate-activated protein kinase (AMPK) inhibitor] or dominant negative form of AMPK (DN-AMPKα1). Thus, fenofibrate considerably inhibited metastatic behaviors of CAL 27 cells might be mediated through blocking NF-κB signaling, resulting in the inhibition of MMPs; these effects were AMPK-dependent rather than PPARα signaling. Our findings provide a molecular rationale, whereby fenofibrate exerts anticancer effects and additional beneficial effects for the treatment of cancer patients. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 866-876, 2016.

LXR ligands sensitize EGFR-TKI-resistant human lung cancer cells in vitro by inhibiting Akt activation

Lung adenocarcinoma cells harboring epidermal growth factor receptor (EGFR) mutations are sensitive to EGFR tyrosine kinase inhibitors (TKIs). Prolonged cancer treatment will induce the development of acquired resistance to EGFR TKI. Here we investigate the effects of two novel liver x receptor (LXR) ligands (T0901317 or GW3965) on the development of acquired resistance to an EGFR TKI gefitinib. We observed known mechanisms of acquired resistance to EGFR TKI, including the EGFR T790M mutation, MET gene amplification and loss of PTEN in the gefitinib-resistant HCC827-8-1 cells. However, we found expression of MET was lower in HCC827-8-1 cells than in HCC827 cells. T0901317 or GW3965 inhibited Akt activation and sensitized HCC827-8-1 cells to gefitinib-induced cytotoxicity. In contrast, LXR ligands alone had no significant effect on HCC827-8-1 cells. In conclusion, this combined treatment may be of interest for treatment of lung adenocarcinomas harboring EGFR mutations and acquired resistance to gefitinib.

Ergostatrien-3β-ol from Antrodia camphorata inhibits diabetes and hyperlipidemia in high-fat-diet treated mice via regulation of hepatic related genes, glucose transporter 4, and AMP-activated protein kinase phosphorylation

This study was designed to explore the effects and mechanism of ergostatrien-3β-ol (EK100) from the submerged whole broth of Antrodia camphorata on diabetes and dyslipidemia in high fat diet (HFD)-fed mice for 12 weeks. The C57BL/6J mouse fed with a high fat diet (HFD) could induce insulin resistance and hyperlipidemia. After 8 week of induction, mice were receiving EK100 (at three dosages) or fenofibrate (Feno) or rosiglitazone (Rosi) or vehicle by oral gavage 4 weeks afterward. HFD-fed mice display increased blood glucose, glycated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), insulin, and leptin levels. These blood markers were significantly lower in EK100-treated mice, and finally ameliorated insulin resistance. EK100 treatment exhibited reduced hepatic ballooning degeneration and size of visceral adipocytes. Glucose transporter 4 (GLUT4) proteins and phosphorylation of Akt in skeletal muscle were significantly increased in EK100- and Rosi-treated mice. EK100, Feno, and Rosi treatment led to significant increases in phosphorylation of AMP-activated protein kinase (phospho-AMPK) protein in both skeletal muscle and liver. Moreover, EK100 caused a decrease in hepatic expressions of phosphenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6 Pase), and decreased glucose production. EK100 lowered blood TG level by inhibition of hepatic fatty acid synthesis by dampening sterol response element binding protein-1c (SREBP-1c) but increasing expression of peroxisome proliferator activated receptor α (PPARα). Moreover, EK100-treated mice reduced blood TC levels by decreased hepatic expressions of SREBP2, which plays a major role in the regulation of cholesterol synthesis. EK100 increased high-density lipoprotein cholesterol (HDL-C) concentrations by increasing expressions of apolipoprotein A-I (apo A-I) in liver tissue. Our findings manifest that EK100 may have therapeutic potential in treating type 2 diabetes associated with hyperlipidemia in HFD-fed mice by regulation of GLUT4, PEPCK, G6 Pase, SREBP1c, SREBP2, apo A-I, and AMPK phosphorylation.

Metabolomics reveal 1-palmitoyl lysophosphatidylcholine production by peroxisome proliferator-activated receptor α

PPARα is well known as a master regulator of lipid metabolism. PPARα activation enhances fatty acid oxidation and decreases the levels of circulating and cellular lipids in obese diabetic patients. Although PPARα target genes are widely known, little is known about the alteration of plasma and liver metabolites during PPARα activation. Here, we report that metabolome analysis-implicated upregulation of many plasma lysoGP species during bezafibrate (PPARα agonist) treatment. In particular, 1-palmitoyl lysophosphatidylcholine [LPC(16:0)] is increased by bezafibrate treatment in both plasma and liver. In mouse primary hepatocytes, the secretion of LPC(16:0) increased on PPARα activation, and this effect was attenuated by PPARα antagonist treatment. We demonstrated that Pla2g7 gene expression levels in the murine hepatocytes were increased by PPARα activation, and the secretion of LPC(16:0) was suppressed by Pla2g7 siRNA treatment. Interestingly, LPC(16:0) activates PPARα and induces the expression of PPARα target genes in hepatocytes. Furthermore, we showed that LPC(16:0) has the ability to recover glucose uptake in adipocytes induced insulin resistance. These results reveal that LPC(16:0) is induced by PPARα activation in hepatocytes; LPC(16:0) contributes to the upregulation of PPARα target genes in hepatocytes and the recovery of glucose uptake in insulin-resistant adipocytes.

Alteration of glucose lowering effect of glibenclamide on single and multiple treatments with fenofibrate in experimental rats and rabbit models

Objective:

Diabetes mellitus is a syndrome of multiple etiologies. Both type 1 and type 2 diabetes lead to multiple abnormalities of lipid and lipoprotein metabolism. The aim of this investigation was to study the influence of fenofibrate on the blood glucose lowering effect of glibenclamide.

Materials and Methods:

Glibenclamide (0.45, 0.23 mg/kg) and fenofibrate (18.1, 9.38 mg/kg) was treated to normal, diabetic rats, and normal rabbits. Blood samples were collected at various time intervals and were analyzed for blood glucose levels using a glucometer.

Results:

Co-administration of fenofibrate with glibenclamide significantly elevated the blood glucose reduction exhibited by glibenclamide.

Conclusion:

The results obtained from single and multiple dose treatments clearly demonstrated the existence of drug-drug interaction at the dose tested in animal models. Hence, this investigation would serve as a preclinical evidence for the effect of fenofibrate on the therapeutic efficacy of glibenclamide.

Effects of d-α-tocopherol supplements on lipid metabolism in a high-fat diet-fed animal model

High-fat diet up-regulates either insulin resistance or triglycerides, which is assumed to be related to the expression of peroxisome proliferator-activated receptor (PPAR)-α and PPAR-γ. The beneficial effects of vitamin E on insulin resistance are well known; however, it is not clear if vitamin E with a high-fat diet alters the expression of PPAR-α and PPAR-γ. We investigated the effects of d-α-tocopherol supplementation on insulin sensitivity, blood lipid profiles, lipid peroxidation, and the expression of PPAR-α and PPAR-γ in a high-fat (HF) diet-fed male C57BL/6J model of insulin resistance. The animals were given a regular diet (CON; 10% fat), a HF diet containing 45% fat, or a HF diet plus d-α-tocopherol (HF-E) for a period of 20 weeks. The results showed that the HF diet induced insulin resistance and altered the lipid profile, specifically the triglyceride (TG) and total cholesterol (TC) levels (P < 0.05). In this animal model, supplementation with d-α-tocopherol improved insulin resistance as well as the serum levels of TG and very-low-density lipoprotein-cholesterol (VLDL-C) (P < 0.05). Moreover, the treatment decreased the levels of malondialdehyde (MDA) in the serum and liver while increasing hepatic PPAR-α expression and decreasing PPAR-γ expression. In conclusion, the oral administration of d-α-tocopherol with a high-fat diet had positive effects on insulin resistance, lipid profiles, and oxidative stress through the expression of PPAR-α and PPAR-γ in a high-fat diet-fed male mice.

Influence of losartan on the hypoglycemic activity of glimepiride in normal and diabetic rats

BACKGROUND

The influence of losartan on the hypoglycemic effect of glimepiride was studied in normal and diabetic rats.

METHOD

Losartan and glimepiride were studied at a dose of 4.5 and 0.09 mg/kg and in normal and diabetic rats, respectively. The blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 10, 12, and 16 hours and analyzed for glucose levels using a glucometer.

RESULTS

Glimepiride exhibited a maximum reduction of blood glucose levels at the 4th hour in normal and diabetic rats. The maximum hypoglycemic effect was observed at the 6th hour in normal rats treated with losartan. In normal rats, losartan did not have any significant effect on the hypoglycemic activity of glimepiride in either the single- or multiple-dose interaction study. In the case of diabetic rats, losartan did not have any significant effect on the hypoglycemic activity of glimepiride in the single-dose interaction study, but a significant change was observed in the multiple-dose study of diabetic rats. Hence, the interaction was found to be pharmacodynamic.

CONCLUSIONS

The study indicates that chronic losartan pretreatment elevates the hypoglycemic effect of glimepiride by a possible rise in insulin sensitivity and improving insulin homeostasis or may be due to the inhibition of CYP2C9. The study also suggests that caution may be recommended concerning combined use of losartan and an oral hypoglycemic agent, glimepiride.

The g0/g1 switch gene 2 is an important regulator of hepatic triglyceride metabolism

Nonalcoholic fatty liver disease is associated with obesity and insulin resistance. Factors that regulate the disposal of hepatic triglycerides contribute to the development of hepatic steatosis. G₀/G₁ switch gene 2 (G0S2) is a target of peroxisome proliferator-activated receptors and plays an important role in regulating lipolysis in adipocytes. Therefore, we investigated whether G0S2 plays a role in hepatic lipid metabolism. Adenovirus-mediated expression of G0S2 (Ad-G0S2) potently induced fatty liver in mice. The liver mass of Ad-G0S2-infected mice was markedly increased with excess triglyceride content compared to the control mice. G0S2 did not change cellular cholesterol levels in hepatocytes. G0S2 was found to be co-localized with adipose triglyceride lipase at the surface of lipid droplets. Hepatic G0S2 overexpression resulted in an increase in plasma Low-density lipoprotein (LDL)/Very-Low-density (VLDL) lipoprotein cholesterol level. Plasma High-density lipoprotein (HDL) cholesterol and ketone body levels were slightly decreased in Ad-G0S2 injected mice. G0S2 also increased the accumulation of neutral lipids in cultured HepG2 and L02 cells. However, G0S2 overexpression in the liver significantly improved glucose tolerance in mice. Livers expressing G0S2 exhibited increased 6-(N-(7-nitrobenz-2-oxa-1-3-diazol-4-yl) amino)-6-deoxyglucose uptake compared with livers transfected with control adenovirus. Taken together, our results provide evidence supporting an important role for G0S2 as a regulator of triglyceride content in the liver and suggest that G0S2 may be a molecular target for the treatment of insulin resistance and other obesity-related metabolic disorders.

A botanical containing freeze dried açai pulp promotes healthy aging and reduces oxidative damage in sod1 knockdown flies

Superoxide dismutase 1 (SOD1), a critical enzyme against oxidative stress, is implicated in aging and degenerative diseases. We previously showed that a nutraceutical containing freeze-dried açai pulp promotes survival of flies fed a high-fat diet or sod1 knockdown flies fed a standard diet. Here, we investigated the effect of açai supplementation initiated at the early or late young adulthood on lifespan, physiological function, and oxidative damage in sod1 knockdown flies. We found that Açai supplementation extended lifespan even when started at the age of 10 days, which is the time shortly before the mortality rate of flies accelerated. Life-long açai supplementation increased lifetime reproductive output in sod1 knockdown flies. Our molecular studies indicate that açai supplementation reduced the protein levels of genes involved in oxidative stress response, cellular growth, and nutrient metabolism. Açai supplementation also affected the protein levels of ribosomal proteins. In addition, açai supplementation decreased the transcript levels of genes involved in oxidative stress response and gluconeogenesis, while increasing the transcript levels of mitochondrial biogenesis genes. Moreover, açai supplementation reduced the level of 4-hydroxynonenal-protein adducts, a lipid peroxidation marker. Our findings suggest that açai supplementation promotes healthy aging in sod1-deficient flies partly through reducing oxidative damage, and modulating nutrient metabolism and oxidative stress response pathways. Our findings provide a foundation to further evaluate the viability of using açai as an effective dietary intervention to promote healthy aging and alleviate symptoms of diseases with a high level of oxidative stress.

11beta-Hydroxysteroid dehydrogenase type 1 inhibitors: novel agents for the treatment of metabolic syndrome and obesity-related disorders?

OBJECTIVE

Metabolic syndrome (MetS) and Cushing's syndrome share common features. It has been proposed that increased glucocorticoid activity at peripheral tissues may play a role in the pathogenesis of MetS and obesity-related disorders. It is well-known that intracellular cortisol concentrations are determined not only by plasma levels but also by the activity of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which catalyzes the conversion of inactive cortisone to active cortisol, especially in the liver and adipose tissue. Another isoenzyme exists, the 11β-hydroxysteroid dehydrogenase type 2, which acts in the opposite direction inactivating cortisol to cortisone in the kidney. This review considers the significance of the 11β-HSD1 inhibition in the treatment of several features of MetS and provides current data about the development of 11β-HSD1 inhibitors, as new agents for this purpose.

MATERIALS/METHODS

Using PubMed, we searched for publications during the last 20years regarding the development of 11β-HSD1 inhibitors.

RESULTS

Emerging data from animal and human studies indicate an association of 11β-HSD1 over-expression with obesity and disorders in glucose and lipid metabolism. This has led to the hypothesis that selective inhibition of 11β-HSD1 could be used to treat MetS and diabetes. Indeed, natural products and older agents such as thiazolidinediones and fibrates seem to exert an inhibitory effect on 11β-HSD1, ameliorating the cardiometabolic profile. In view of this concept, novel compounds, such as adamantyltriazoles, arylsulfonamidothiazoles, anilinothiazolones, BVT2733, INCB-13739, MK-0916 and MK-0736, are currently under investigation and the preliminary findings from both experimental and human studies show a favourable effect on glucose and lipid metabolism, weight reduction and adipokine levels.

CONCLUSIONS

Many compounds inhibiting 11β-ΗSD1 are under development and preliminary data about their impact on glucose metabolism and obesity-related disorders are encouraging.

Candidate gene expression affects intramuscular fat content and fatty acid composition in pigs

The objective of this study was to correlate the expression pattern of candidate genes with the intramuscular fat (IMF) content and fatty acid composition of the Longissimus dorsi muscle of Duroc × Shanzhu commercial crossbred pigs. Animals of both sexes were slaughtered at a body weight of about 90 kg. The IMF content and fatty acid composition of the Longissimus dorsi muscle were measured and correlated with candidate genes mRNA expression (AdPLA, ADRB3, LEPR, MC4R, PPARγ, PPARα, LPL, PEPCK, and SCD). Females presented higher IMF content (p < 0.05) than males. The total saturated fatty acid (SFA) in males was greater (p < 0.01), whereas the total monounsaturated fatty acid (MUFA) (p < 0.01) and polyunsaturated fatty acid (PUFA) (p < 0.05) were lower than in females. The expressions of AdPLA, MC4R, PEPCK, and SCD correlated with the IMF content (p < 0.05). AdPLA showed a positive association with MUFA and a negative association with SFA (p < 0.05). LEPR and MC4R were both positively and significantly associated with C18:3 and C20:0 (p < 0.05). PPARα and PPARγ were negatively correlated with SFA, and PPARγ was positively associated with MUFA (p < 0.05). LPL was positively associated with MUFA and negatively associated with SFA (p < 0.05). PEPCK was negatively correlated with PUFA (p < 0.05). SCD was positively associated with MUFA (p < 0.05). The revealed correlations may confirm that these candidate genes are important for fat deposition and fatty acid composition in pigs, and the evaluation and use of these genes may be useful for improving porcine meat quality.

The effects of dietary fatty acid composition in the post-sucking period on metabolic alterations in adulthood: can ω3 polyunsaturated fatty acids prevent adverse programming outcomes?

Early life nutrition is important in the regulation of metabolism in adulthood. We studied the effects of different fatty acid composition diets on adiposity measures, glucose tolerance, and peripheral glucocorticoid (GC) metabolism in overfed neonatal rats. Rat litters were adjusted to a litter size of three (small litters (SLs)) or ten (normal litters (NLs)) on postnatal day 3 to induce overfeeding or normal feeding respectively. After weaning, SL and NL rats were fed a ω6 polyunsaturated fatty acid (PUFA) diet (14% calories as fat, soybean oil) or high-saturated fatty acid (high-fat; 31% calories as fat, lard) diet until postnatal week 16 respectively. SL rats were also divided into the third group fed a ω3 PUFA diet (14% calories as fat, fish oil). A high-fat diet induced earlier and/or more pronounced weight gain, hyperphagia, glucose intolerance, and hyperlipidemia in SL rats compared with NL rats. In addition, a high-fat diet increased 11β-hsd1 (Hsd11b1) mRNA expression and activity in the retroperitoneal adipose tissue of both litter groups compared with standard chow counterparts, whereas high-fat feeding increased hepatic 11β-hsd1 mRNA expression and activity only in SL rats. SL and a high-fat diet exhibited significant interactions in both retroperitoneal adipose tissue and hepatic 11β-HSD1 activity. Dietary ω3 PUFA offered protection against glucose intolerance and elevated GC exposure in the retroperitoneal adipose tissue and liver of SL rats. Taken together, the results suggest that dietary fatty acid composition in the post-sucking period may interact with neonatal feeding and codetermine metabolic alterations in adulthood.

AMP-activated protein kinase: an emerging drug target to regulate imbalances in lipid and carbohydrate metabolism to treat cardio-metabolic diseases

The adenosine monophosphate-activated protein kinase (AMPK) is a metabolic sensor of energy metabolism at the cellular as well as whole-body level. It is activated by low energy status that triggers a switch from ATP-consuming anabolic pathways to ATP-producing catabolic pathways. AMPK is involved in a wide range of biological activities that normalizes lipid, glucose, and energy imbalances. These pathways are dysregulated in patients with metabolic syndrome (MetS), which represents a clustering of major cardiovascular risk factors including diabetes, lipid abnormalities, and energy imbalances. Clearly, there is an unmet medical need to find a molecule to treat alarming number of patients with MetS. AMPK, with multifaceted activities in various tissues, has emerged as an attractive drug target to manage lipid and glucose abnormalities and maintain energy homeostasis. A number of AMPK activators have been tested in preclinical models, but many of them have yet to reach to the clinic. This review focuses on the structure-function and role of AMPK in lipid, carbohydrate, and energy metabolism. The mode of action of AMPK activators, mechanism of anti-inflammatory activities, and preclinical and clinical findings as well as future prospects of AMPK as a drug target in treating cardio-metabolic disease are discussed.

Increasing the folic acid content of maternal or post-weaning diets induces differential changes in phosphoenolpyruvate carboxykinase mRNA expression and promoter methylation in rats

Environmental exposures throughout the life course, including nutrition, may induce phenotypic and epigenetic changes. There is limited information about how timing affects the nature of such effects induced by a specific nutritional exposure. We investigated the effect of increased exposure to folic acid before birth or during the juvenile-pubertal period in rats on the epigenetic regulation of glucose homeostasis. Rats were fed either a folic acid-adequate (AF; 1 mg/kg feed) or a folic acid-supplemented (FS; 5 mg/kg feed) diet from conception until delivery and then an AF diet during lactation. Juvenile rats were fed either the AF or the FS diet from weaning for 28 d and then an AF diet. Liver and blood were collected after a 12 h fast between postnatal days 84 and 90. Maternal FS diet increased plasma glucose concentration significantly (P < 0·05) in females, but not in males. Post-weaning FS diet decreased glucose concentration significantly in females, but increased glucose concentration in males. There were no effects of the FS diet on phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression in males, while the pattern of expression was related to plasma glucose concentration in females. The FS diet induced specific changes in the methylation of individual CpG in females, but not in males, which were related to the time of exposure. Methylation of CpG - 248 increased the binding of CCAAT-enhancer-binding protein β to the PEPCK promoter. Together, these findings show that both the period during the life course and sex influence the effect of increased exposure to folic acid on the epigenetic regulation of PEPCK and glucose homeostasis.

Critical role of chemokine (C-C motif) receptor 2 (CCR2) in the KKAy + Apoe -/- mouse model of the metabolic syndrome

AIMS/HYPOTHESIS

Chemokines and their receptors such as chemokine (C-C motif) receptor 2 (CCR2) may contribute to the pathogenesis of the metabolic syndrome via their effects on inflammatory monocytes. Increased accumulation of CCR2-driven inflammatory monocytes in epididymal fat pads is thought to favour the development of insulin resistance. Ultimately, the resulting hyperglycaemia and dyslipidaemia contribute to development of the metabolic syndrome complications such as cardiovascular disease and diabetic nephropathy. Our goal was to elucidate the role of CCR2 and inflammatory monocytes in a mouse model that resembles the human metabolic syndrome.

METHODS

We generated a model of the metabolic syndrome by backcrossing KKAy ( + ) with Apoe ( -/- ) mice (KKAy ( + ) Apoe ( -/- )) and studied the role of CCR2 in this model system.

RESULTS

KKAy ( + ) Apoe ( -/- ) mice were characterised by the presence of obesity, insulin resistance, dyslipidaemia and increased systemic inflammation. This model also manifested two complications of the metabolic syndrome: atherosclerosis and diabetic nephropathy. Inactivation of Ccr2 in KKAy (+) Apoe ( -/- ) mice protected against the metabolic syndrome, as well as atherosclerosis and diabetic nephropathy. This protective phenotype was associated with a reduced number of inflammatory monocytes in the liver and muscle, but not in the epididymal fat pads; circulating levels of adipokines such as leptin, resistin and adiponectin were also not reduced. Interestingly, the proportion of inflammatory monocytes in the liver, pancreas and muscle, but not in the epididymal fat pads, correlated significantly with peripheral glucose levels.

CONCLUSIONS/INTERPRETATION

CCR2-driven inflammatory monocyte accumulation in the liver and muscle may be a critical pathogenic factor in the development of the metabolic syndrome.

Synthesis and biological evaluation of orally active hypolipidemic agents

A series of novel fenofibric acid ester prodrugs 1c-1h were synthesized and evaluated with the aim of obtaining potent hypolipidemic agents. Prodrugs 1c and 1d exhibited potent hypochlolesterolemic activity, lowering the mice plasma triglyceride level up to 47% in Swiss albino mice after oral administration of 50 mg/kg/day for 8 days. Fenofibric acid ester prodrugs 1c-1h were found lipophilic like fenofibrate (1b), indicated by partition coefficients measured in octanol-buffer system at pH 7.4. On the basis of in vivo studies, prodrugs 1c and 1d emerged as potent hypolipidemic agents.

Mango modulates body fat and plasma glucose and lipids in mice fed a high-fat diet

Consumption of fruits and vegetables has been investigated for their role in the prevention of many chronic conditions. Among the fruits, mango provides numerous bioactive compounds such as carotenoids, vitamin C and phenolic compounds, which have been shown to have antioxidant and anti-inflammatory properties. The present study examined the effects of dietary supplementation of freeze-dried mango pulp, in comparison with the hypolipidaemic drug, fenofibrate, and the hypoglycaemic drug, rosiglitazone, in reducing adiposity and alterations in glucose metabolism and lipid profile in mice fed a high-fat (HF) diet. Male C57BL/6J mice were randomly divided into six treatment groups (eight to nine/group): control (10 % energy from fat); HF (60 % energy from fat); HF+1 or 10 % freeze-dried mango (w/w); HF+fenofibrate (500 mg/kg diet); HF+rosiglitazone (50 mg/kg diet). After 8 weeks of treatment, mice receiving the HF diet had a higher percentage body fat (P = 0·0205) and epididymal fat mass (P = 0·0037) compared with the other treatment groups. Both doses of freeze-dried mango, similar to fenofibrate and rosiglitazone, prevented the increase in epididymal fat mass and the percentage of body fat. Freeze-dried mango supplementation at the 1 % dose improved glucose tolerance as shown by approximately 35 % lower blood glucose area under the curve compared with the HF group. Moreover, freeze-dried mango lowered insulin resistance, as indicated by the homeostasis model assessment of insulin resistance, to a similar extent as rosiglitazone and modulated NEFA. The present findings demonstrate that incorporation of freeze-dried mango in the diet of mice improved glucose tolerance and lipid profile and reduced adiposity associated with a HF diet.

Nectarine promotes longevity in Drosophila melanogaster

Fruits containing high antioxidant capacities and other bioactivities are ideal for promoting longevity and health span. However, few fruits are known to improve the survival and health span in animals, let alone the underlying mechanisms. Here we investigate the effects of nectarine, a globally consumed fruit, on life span and health span in Drosophila melanogaster. Wild-type flies were fed standard, dietary restriction (DR), or high-fat diet supplemented with 0-4% nectarine extract. We measured life span, food intake, locomotor activity, fecundity, gene expression changes, and oxidative damage indicated by the level of 4-hydroxynonenal-protein adduct in these flies. We also measured life span, locomotor activity, and oxidative damage in sod1 mutant flies on the standard diet supplemented with 0-4% nectarine. Supplementation with 4% nectarine extended life span, increased fecundity, and decreased expression of some metabolic genes, including a key gluconeogenesis gene, PEPCK, and oxidative stress-response genes, including peroxiredoxins, in female wild-type flies fed the standard, DR, or high-fat diet. Nectarine reduced oxidative damage in wild-type females fed the high-fat diet. Moreover, nectarine improved the survival of and reduced oxidative damage in female sod1 mutant flies. Together, these findings suggest that nectarine promotes longevity and health span partly by modulating glucose metabolism and reducing oxidative damage.

11beta-Hydroxysteroid dehydrogenase type 1 is an important regulator at the interface of obesity and inflammation

Systemic glucocorticoid excess, as exemplified by the Cushing syndrome, leads to obesity and all further symptoms of the metabolic syndrome. The current obesity epidemic, however, is not characterized by increased plasma cortisol concentrations, but instead comes along with chronic low-grade inflammation in adipose tissue and concomitant increased levels of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1, gene HSD11B1), a parameter known to cause obesity in a mouse model. 11beta-HSD1 represents an intracellular amplifier of active glucocorticoid, thus enhances the associated effects on the inflammatory response as well as on nutrient and energy metabolism, and may therefore cause and exacerbate obesity by local increase of glucocorticoid concentrations. Obtained by extensive literature and database searching, the present review includes comprehensive lists of primary glucocorticoid-sensitive genes and gene products as well as of the thus far known regulators of HSD11B1 expression with implication in inflammation and metabolic disease. Collectively, the data clearly show that, in addition to amplifying active glucocorticoid and thus profoundly modulating inflammation and nutrient metabolism, 11beta-HSD1 is subject to tight control of multiple additional immunomodulatory and metabolic regulators. Hence, 11beta-HSD1 acts at the interface of inflammation and obesity and represents an efficient integrator and effector of local inflammatory and metabolic state.

Açai palm fruit (Euterpe oleracea Mart.) pulp improves survival of flies on a high fat diet

Reducing oxidative damage is thought to be an effective aging intervention. Açai, a fruit indigenous to the Amazon, is rich in phytochemicals that possesses high anti-oxidant activities, and has anti-inflammatory, anti-cancer and anti-cardiovascular disease properties. However, little is known about its potential anti-aging properties especially at the organismal level. Here we evaluated the effect of açai pulp on modulating lifespan in Drosophila melanogaster. We found that açai supplementation at 2% in the food increased the lifespan of female flies fed a high fat diet compared to the non-supplemented control. We measured transcript changes induced by açai for age-related genes. Although transcript levels of most genes tested were not altered, açai increased the transcript level of l(2)efl, a small heat-shock-related protein, and two detoxification genes, GstD1 and MtnA, while decreasing the transcript level of phosphoenolpyruvate carboxykinase (Pepck), a key gene involved in gluconeogenesis. Furthermore, açai increased the lifespan of oxidative stressed females caused by sod1 RNAi. This suggests that açai improves survival of flies fed a high fat diet through activation of stress response pathways and suppression of Pepck expression. Açai has the potential to antagonize the detrimental effect of fat in the diet and alleviate oxidative stress in aging.