There is an increasing prevalence of coincident cerebrovascular deficiency and cognitive dysfunction with aging. Increased oxidative stress as well as inflammation that occurs with aging are associated with the impairment of cerebral vascularization. Interestingly, Resveratrol (RSV), a natural phytoalexin, is known to be a strong antioxidant and possesses anti-inflammatory properties. Collectively, these observations strongly suggest that RSV could protect against cerebral vascularization defect and then improves the decline cognitive function associated with aging. In order to test this hypothesis, we investigated the effect of a long-term RSV treatment (1.25 mg/day for 5 months) on cognitive performances of animals that we have allowed to age normally. Then, we further analyzed the gene expression profile and the cerebral blood flow in the brain. By means of novel object recognition (NOR) test, we observed that RSV enhanced NOR performances of aged rats. In addition, RSV enhanced cerebral blood flow during NOR task in aged rats. Using microarrays experiments, we also showed that several pathways related to inflammation and oxidative stress (Eicosanoid signaling, MIF-mediated innate immunity, NF-kB signaling, TNFR2 signaling, IL6 signaling, Production of nitric oxide and ROS) were down-regulated in the brain of RSV treatments rats compared to control rats. In conclusion, these results support that a long-term treatment with RSV improves cognitive performance in the elderly male rat model. This effect is associated with an increase in cerebral blood flow and a decrease in the expression of several pro-inflammatory pathways in the brain.

The polyphenols resveratrol (RSV) and curcumin (Cur) are phytoalexines and natural antibiotics with numerous pharmacological functions and metabolic impacts. Recent evidences show a broad control of gut microbiota by polyphenols which could influence glycemic regulation. The aim of this work is to estimate the respective effect of RSV and Cur alone or in association on the control of glycemia and on gut microbiota. A 5-week chronic treatment of hyperglycemic mice with RSV and/or Cur resulted in a differential effect on glucose tolerance test and modified gut microbiome. We precisely identified groups of bacteria representing a specific signature of the glycemic effect of RSV. Inferred metagenomic analysis and metabolic pathway prediction showed that the sulfur and branched-chain amino-acid (BCAA) metabolic activities are tightly correlated with the efficacy of RSV for the control of glycaemia. The impact on BCAA metabolism was further validated by serum metabolomics analysis. Altogether, we show that polyphenols specifically impact gut microbiota and corresponding metabolic functions which could be responsible for their therapeutic role.

Type 2 diabetic women have a high risk of mortality via myocardial infarction even with anti-diabetic treatments. Resveratrol (RSV) is a natural polyphenol, well-known for its antioxidant property, which has also shown interesting positive effects on mitochondrial function. Therefore, we aim to investigate the potential protective effect of 1 mg/kg/day of RSV on high energy compounds, during myocardial ischemia-reperfusion in type 2 diabetic female Goto-Kakizaki (GK) rats. For this purpose, we used 31P magnetic resonance spectroscopy in isolated perfused heart experiments, with a simultaneous measurement of myocardial function and coronary flow. RSV enhanced adenosine triphosphate (ATP) and phosphocreatine (PCr) contents in type 2 diabetic hearts during reperfusion, in combination with better functional recovery. Complementary biochemical analyses showed that RSV increased creatine, total adenine nucleotide heart contents and citrate synthase activity, which could be involved in better mitochondrial functioning. Moreover, improved coronary flow during reperfusion by RSV was associated with increased eNOS, SIRT1, and P-Akt protein expression in GK rat hearts. In conclusion, RSV induced cardioprotection against ischemia-reperfusion injury in type 2 diabetic female rats via increased high energy compound contents and expression of protein involved in NO pathway. Thus, RSV presents high potential to protect the heart of type 2 diabetic women from myocardial infarction.

We revisited the action of a carotenoid, the lycopene, on the expression of proinflammatory genes, reactive oxygen species (ROS) production, and metalloprotease (MMP9) activity. THP1 and Caco2 cell lines were used as in vitro models for the two main cell types found in intestine tissue, that is, monocytes and epithelial cells. Proinflammatory condition was induced using either phorbol ester acetate (PMA), lipopolysaccharide (LPS) or tumor necrosis factor (TNF). In THP1 cells, short term pretreatment (2 h) with a low concentration (2 μM) of lycopene reinforce proinflammatory gene expression. The extent of the effect of lycopene is dependent on the proinflammtory stimulus (PMA, LPS or TNF) used. Lycopene enhanced MMP9 secretion via a c-AMP-dependent process, and reduced ROS production at higher concentrations than 2 μM. Cell culture media, conditioned by PMA-treated monocytes and then transferred on CaCo-2 epithelial cells, induced a proinflammatory state in these cells. The extent of this inflammatory effect was reduced when cells has been pretreated (12 h) with lycopene. At low concentration (2 μM or less), lycopene appeared to promote an inflammatory state not correlated with ROS modulation. At higher concentration (5 μM–20 μM), an anti-inflammatory effect takes place as a decrease of ROS production was detected. So, both concentration and time have to be considered in order to define the exact issue of the effect of carotenoids present in meals.

We have developed an innovative soluble galenic form to overcome the low absorption of trans-Resveratrol (t-Res) as a dry powder. We present here data on pharmacokinetics, bioavailability, and toxicity of t-Res in human volunteers treated with this soluble form, plus additional data on biological effects in rodents. Fifteen healthy volunteers of both sexes received 40 mg of t-Res in two forms, the soluble formulation (caplets) and the original powder (capsules), in a crossover design. Blood samples were collected at 15 min, 30 min, and every hour for 5 h. Plasma concentrations of t-Res and its metabolites were analyzed by liquid chromatography and mass spectrometry. The single dose (40 mg) of the soluble t-Res was well absorbed and elicited biologically efficient blood levels (0.1-6 μM) for several hours, despite metabolization into glucuronide and sulfate conjugates coupled to renal elimination. In contrast, t-Res administered as a dry powder barely elicited efficient blood levels for a short duration. The new formulation led to 8.8-fold higher t-Res levels in plasma versus the powder. t-Res metabolism was not modified and neither intolerance nor toxicity were observed during the study and the following week. The soluble formulation elicited a robust anti-inflammatory effect in various tissues of mice fed a high-fat diet, while dry powder t-Res was almost inactive. Our data suggest that significant improvements in t-Res bioavailability and efficiency can be obtained by this soluble galenic form, also allowing lower doses. The use of t-Res in human therapy is thus greatly facilitated and the toxicity risk is reduced.

Recent data suggest that apart from its well-known role in the regulation of xenobiotic metabolizing enzymes, AhR is also involved in inflammation. However, the influence of inflammation on AhR expression remains unknown. Here, we demonstrated that proinflammatory conditions induced by either PMA or IL-1 β enhance AhR expression in Caco-2 cells. This was associated with an increase in AhR promoter activity. By means of directed mutagenesis experiments and the use of proteasome inhibitors, we demonstrated that inflammation-induced AhR expression involved the NF κ B pathway but not AP-1. Moreover, conditioned media from PMA-treated Caco-2 cells were also able to induce AhR expression, and this induction was repressed by anti-IL-1 β blocking antibodies. Similar results were obtained with conditioned media from PMA-treated THP-1 cells. Taken together, these data suggest that AhR could be involved in vivo in an inflammatory loop. AhR was recently suspected to be implicated in inflammatory bowel disease. Our results support this hypothesis and suggest that AhR could be a new target for inflammatory bowel disease patient management.

La presente invention se rapporte a une composition contenant au moins un polyphenol, au moins un polyethylene glycol et/ou un equivalent fonctionnel et au moins un ether glycolique et/ou un equivalent fonctionnel pour son application comme medicament. La composition selon l'invention peut etre egalement utilisee comme complement alimentaire ou nutraceutique.

BACKGROUND:We previously showed that blood serum induced cytochrome P450 1A1 (CYP1A1) monooxygenase expression in vitro. OBJECTIVE:Our purpose was (i) to identify the molecular mechanism involved and (ii) to characterize the inducer compound(s) in serum involved at least in part. METHODS:Serum was fractionated on hydrophobic columns. PPARα involvement was demonstrated by gene reporter assays, DNA mutagenesis and EMSA. Gene expression was evaluated by qRT-PCR. Serum samples were analyzed using HS-SPME-GC-MS. RESULTS:The inductive effect of serum did not depend on the AhR pathway and was enhanced by cotransfection of PPARα cDNA. Mutations in the PPAR response elements of the CYP1A1 gene promoter suppressed this effect. One of the PPRE sites appeared highly specific for human PPARα, an unreported PPRE property. A link was found between CYP1A1 inducibility and serum hydrophobic compounds. Characterization of sera showed that hexanal, a metabolite produced by peroxidation of linoleic acid, was involved in CYP1A1 induction by serum, possibly along with other serum entities. CONCLUSION:We demonstrate that serum induces CYP1A1 via the PPARα pathway and that hexanal is one of the serum inducers. The two PPRE sites within the CYP1A1 promoter are functional and one of them is specific for PPARα.

Resveratrol (RSV) is a potent anti-diabetic agent when used at high doses. However, the direct targets primarily responsible for the beneficial actions of RSV remain unclear. We used a formulation that increases oral bioavailability to assess the mechanisms involved in the glucoregulatory action of RSV in high-fat diet (HFD)-fed diabetic wild type mice. Administration of RSV for 5 weeks reduced the development of glucose intolerance, and increased portal vein concentrations of both Glucagon-like peptid-1 (GLP-1) and insulin, and intestinal content of active GLP-1. This was associated with increased levels of colonic proglucagon mRNA transcripts. RSV-mediated glucoregulation required a functional GLP-1 receptor (Glp1r) as neither glucose nor insulin levels were modulated in Glp1r-/- mice. Conversely, levels of active GLP-1 and control of glycemia were further improved when the Dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin was co-administered with RSV. In addition, RSV treatment modified gut microbiota and decreased the inflammatory status of mice. Our data suggest that RSV exerts its actions in part through modulation of the enteroendocrine axis in vivo.

We demonstrate that intestinal inflammation caused by high-fat diet is increased by the environmental contaminant benzo[a]pyrene. Our in vivo results indicate that a high-fat diet (HFD) induces a pre-diabetic state in mice compared with animals fed normal chow. HFD increased IL-1betamRNA concentration in the jejunum, colon, and liver, and TNFalpha was increased in the colon and strongly increased in the liver. HFD also increased the expression of other genes related to type 2 diabetes, such as the uncoupling protein UCP2, throughout the bowel and liver, but not in the colon. The treatment of HFD with BaP enhanced the expression of IL-1beta in the liver and TNFalpha throughout the bowel and in the liver. Adding BaP to the diet also caused a significant decrease in the expression of the incretin glucagon-like peptide 1, which plays an important role in insulin secretion. Our results suggest that intestinal inflammation may be involved in the onset of type 2 diabetes and that chronic exposure to environmental polycyclic aromatic hydrocarbons can increase the risk of type 2 diabetes by inducing pro-inflammatory cytokine production.

Aucune molécule thérapeutique ne permet de prendre en compte la complexité du désordre métabolique de manière globale. La prise de compléments alimentaires pourrait s’avérer un soutien efficace. Le resvératrol pourrait servir à une telle approche thérapeutique, pharmacologique et alicamenteuse. Son mécanisme d’action serait basé sur des effets antioxydants, anti-inflammatoires (inhibition de NFκB et AP-1), d’activation mitochondriale via les sirtuines et PGC-1, d’activation de la voie PPARγ (cible des thiazolidinediones) et enfin antagonistes de polluants diabétogènes reconnus. Le resvératrol, en tant que complément alimentaire semble donc un candidat prometteur pour l’accompagnement du traitement du diabète de type 2 et de l’obésité. The complexity of metabolic disorders involved in type 2 diabetes cannot be currently addressed by the use of a single drug. Nutraceuticals such as resveratrol may be a useful addition to antidiabetic therapy. Resveratrol acts through an array of mechanisms. These involve antioxydative and antiinflammatory effects (NFκB and AP-1 inhibition), mitochondrial activation via PGC-1 and the sirtuin pathway, PPARγ activation and antagonization of diabetogenic pollutants (dioxins, tobacco smoke arylhydrocarbons) through Ah receptor inhibition. Resveratrol thus appears a good candidate as a neutraceutical support for the therapy of obesity and type 2 diabetes.

In this work we demonstrate that Caco-2 cell treatment with WY-14643 (a potent PPARalpha agonist) causes an increase in AhR expression. Luciferase assays and directed mutagenesis experiments showed that induction mainly occurred at transcriptional level and involved a PPRE site located within the AhR promoter. These results were further confirmed by the use of PPARalpha knockout mice in which AhR induction by WY14643 was abrogated. In addition to CYP1 regulation, AhR has been described as being involved in inflammation, so we also studied the effect of AhR regulation by PPARalpha on the expression of some inflammation target genes. 3-Methylcholanthrene (a potent AhR agonist) increased the expression (mRNA) of the major inflammatory targets IL-1beta and MMP9. WY-14643 co-treatment abrogated the 3-methylcholanthrene pro-inflammatory effect. Hence the anti-inflammatory effect of PPARalpha overrides the pro-inflammatory effect of AhR.

CYP1A1 is an extrahepatic enzyme largely involved in the bioactivation of various procarcinogens such as polycyclic aromatic hydrocarbons (PAHs) and arylamines. CYP1A1 expression is mainly regulated by AhR. Our laboratory has recently shown a new CYP1A1 regulation pathway involving PPARα. The aim of this study was to evaluate, in a Caco-2 cell line, the effect of a coexposure to 3-methylcholanthrene (3MC, AhR ligand) and WY-14643 (WY, PPARα ligand) on CYP1A1 expression (enzymatic activity, mRNA level and promoter activity). An additive effect on CYP1A1 expression was shown in cells coexposed with 3MC (0.1 or 1μM) and a low WY concentration (30μM) whereas a potentiating effect was observed after coexposure with 3MC (0.1 or 1μM) and a high WY concentration (200μM). Furthermore, 200μM WY, alone or with 3MC, was able to increase the AhR protein level (two-fold). In conclusion, coexposure with 3MC and the PPARα agonist WY leads to an additive or potentiating effect on CYP1A1 inducibility, depending on the WY concentration. Furthermore, at high concentration (200μM), WY induced AhR expression, which could explain the potentiating effect on CYP1A1 inducibility observed after addition of an AhR ligand (3MC). This phenomenon should be taken into account for risk assessment involving CYP1A1 induction.

CYP1A1 isoform is mainly regulated by the transcription factor AhR and to a lesser extent by the nuclear receptor RAR. The effect of a coexposure with 3MC, a AhR ligand, and RA, a RAR ligand, which are, respectively, strong and weak CYP1A1 inducers, is poorly known. We showed in Caco-2 cells that addition of RA significantly decreased 3MC-induced CYP1A1 expression by −55% for mRNA level and −30% for promoter and enzymatic activities. We further showed that RA decreased AhR protein level. Moreover, a physical interaction between AhR and the RAR-corepressor SMRT has been described in vitro. Using the corepressor inhibitor TSA, transfected-cells with SMRT cDNA, and coimmunoprecipitation experiments, we demonstrated that RA addition repressed AhR function through a marked AhR/SMRT physical interaction. This interaction explains the decrease of 3MC-induced CYP1A1 expression. This new mechanism involving the repression of AhR-induced CYP1A1 expression by retinoids allows better knowledge of the CYP1A1 regulation.

BACKGROUND AND AIMS:Cytochrome P450 1A1 catalyzes the degradation of endobiotics (estradiol, fatty acids, and so on) and the bioactivation of numerous environmental procarcinogens, such as arylamines and polycyclic aromatic hydrocarbons, that are found in food. Several peroxisome proliferators and arachidonic acid derivatives enhance cytochrome P450 1A1 activity, but the mechanisms involved remain unknown. The aim of this work was to study the role of peroxisome proliferator-activated receptors in cytochrome P450 1A1 gene induction.METHODS:The role of peroxisome proliferator-activated receptor transcription factors in cytochrome P450 1A1 induction was assessed by means of enzymatic activities, quantitative real-time polymerase chain reaction, gene reporter assays, mutagenesis, and electrophoretic mobility shift assay.RESULTS:We show that peroxisome proliferator-activated receptor-alpha agonists (WY-14643, bezafibrate, clofibrate, and phthalate) induce human cytochrome P450 1A1 gene expression, whereas 2,4-thiazolidinedione, a specific peroxisome proliferator-activated receptor-gamma agonist, represses it. The induction of cytochrome P450 1A1 transcripts by WY-14643 was associated with a marked increase of ethoxyresorufin O -deethylase activity (10-fold at 200 mumol/L). Transfection of peroxisome proliferator-activated receptor-alpha complementary DNA enhanced cytochrome P450 1A1 messenger RNA induction by WY-14643, although WY-14643 failed to activate xenobiotic responsive element sequences. Two peroxisome proliferator response element sites were located at positions -931/-919 and -531/-519 of the cytochrome P450 1A1 promoter. Their inactivation by directed mutagenesis suppressed the inductive effect of WY-14643 on cytochrome P450 1A1 promoter activation. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay experiments showed that the 2 cytochrome P450 1A1 peroxisome proliferator response element sites bind the peroxisome proliferator-activated receptor-alpha/retinoid X receptor-alpha heterodimer.CONCLUSIONS:We describe here a new cytochrome P450 1A1 induction pathway involving peroxisome proliferator-activated receptor-alpha and 2 peroxisome proliferator response element sites, indicating that peroxisome proliferator-activated receptor-alpha ligands, which are common environmental compounds, may be involved in carcinogenesis.

CYP1A1 is largely involved in carcinogenesis through the bioactivation of numerous procarcinogens. Exposure to environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) leads to induction of CYP1A1 via AhR pathway. We have previously demonstrated that fetal bovine serum (FBS) induces CYP1A1 gene transcription. In this work, we show evidence that the serum does not contain an AhR ligand and we evaluated the effect of a 3-methylcholanthrene (3-MC) and FBS cotreatment on CYP1A1 expression. CYP1A1 activity was potentiated by this treatment. This potentiation was at least in part associated with an increase of the CYP1A1 mRNA and gene transcription levels. FBS potentiation of CYP1A1 PAH-mediated induction was related to a significant increase of single strand breaks of DNA as compared to a single 3-MC treatment. Moreover, we demonstrated that human serum induces CYP1A1 with a high interindividual variability. The potentiation by serum of polycyclic aromatic hydrocarbon CYP1A1 induction could be involved in the etiology of some human cancers.