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International audience; Sarcopenia, the age-related loss of skeletal muscle mass, is associated with lipid accumulation and anabolic resistance; phenomena also observed in obesity and worsen when obesity and aging are combined. The endocannabinoid system (ECS) is overactivated in obesity, but its role in aging obesity-related muscle dysfunction is unknown. The aims of this study were to evaluate the effect of inhibition of the ECS by rimonabant (RIM) on the metabolic alterations induced by a high-fat high-sucrose diet and on skeletal muscle mass/function in aged mice. Eighteen-month-old male mice were subjected to a control (CTL) or a high-fat high-sucrose (HFHS) diet for 24 weeks. Mice were administered with saline or RIM (10 mg/kg/day) for the last 4 weeks of the diet. Skeletal muscle function was evaluated by open-field, rotarod, and grip strength tests. Metabolic alterations in liver, adipose tissue, and skeletal muscle were investigated by quantitative RT-PCR. Body mass was higher in HFHS mice compared to CTL mice (48.0 ± 1.5 vs. 33.5 ± 0.7 g, P < 0.01), as a result of fat accumulation (34.8 ± 1.0 vs. 16.7 ± 0.8%, P < 0.01). RIM reduced body fat mass in both CTL (À16%, P < 0.05) and HFHS conditions (À40%, P < 0.01), without affecting hindlimb skeletal muscle mass. In HFHS mice, grip strength evolution was improved (À0.29 ± 0.06 vs. À0.49 ± 0.06 g/g lean mass, P < 0.05), and rotarod activity was increased by %60% in response to RIM (45.9 ± 6.3 vs. 28.5 ± 4.6 cm, P < 0.05). Lipolysis and b-oxidation genes were upregulated in the liver as well as genes involved in adipose tissue browning. These results demonstrate that inhibition of the ECS induces metabolic changes in liver and adipose tissue associated with a reversion of the obese phenotype and that RIM is able to improve motor coordination and muscle strength in aged mice, without affecting skeletal muscle mass. NEW & NOTEWORTHY In 24-month-old mice submitted to high-fat high-sucrose-induced obesity, inhibition of the endocannabinoid system by rimonabant reversed the obese phenotype by promoting adipose tissue browning and b-oxidation in the liver but not in skeletal muscle. These metabolism modifications are associated with improved skeletal muscle function.

International audience; Alterations in adipose tissue (AT) metabolism related to inflammation and adipokine's production lead to perturbations in its capacity to store lipids and release fatty acids (FA) during feeding/fasting transition or during exercise. Exercise has a beneficial effect on AT metabolism, but conventional trainings are not always suitable for patients with functional limitations. Dynamic eccentric (ECC) exercise prevents the accumulation of AT and may then overcome those limitations. Consequently, this study aimed at investigating AT's adaptations after ECC training. Nine-week-old male rats were randomly assigned to a control sedentary or three-trained groups for which treadmill slopes modulated exercise oxygen consumption (VO2) and mechanical work (n = 15 per group): (1) + 15% uphill-concentric group (CONC), (2) - 15% downhill group (ECC15, same mechanical work as CONC) and (3) - 30% downhill group (ECC30, same VO2, or oxygen cost as CONC). Body composition and energy expenditure (EE) were measured before and after 8 weeks of training. Subcutaneous AT was collected to study total FA profile and gene expression. Higher total EE was driven by lean mass gain in trained animals. In AT, there was a decrease in arachidonic acid with CONC or ECC15 training. Increased adiponectin, leptin, lipases, Glut4 and Igf1 mRNA levels in ECC15 group suggested major metabolic adaption in AT. In conclusion, ECC could induce beneficial modifications in AT fatty acid profile and the expression of key genes related to metabolism and insulin sensitivity.

Obesity is characterized by profound alterations in adipose tissue (AT) biology, leading to whole body metabolic disturbances such as insulin resistance and cardiovascular diseases. These alterations are related to the development of a local inflammation, fibrosis, hypertrophy of adipocytes, and dysregulation in energy homeostasis, notably in visceral adipose tissue (VAT). Omega 3 (n-3) fatty acids (FA) have been described to possess beneficial effects against obesity-related disorders, including in the AT; however, the long-term effect across generations remains unknown. The current study was conducted to identify if supplementation with n-3 polyunsaturated FA (PUFA) for three generations could protect from the consequences of an obesogenic diet in VAT. Young mice from the third generation of a lineage receiving a daily supplementation (1% of the diet) with fish oil rich in eicosapentaenoic acid (EPA) or an isocaloric amount of sunflower oil, were fed a high-fat, high-sugar content diet for 4 months. We explore the transcriptomic adaptations in each lineage using DNA microarray in VAT and bioinformatic exploration of biological regulations using online databases. Transgenerational intake of EPA led to a reduced activation of inflammatory processes, perturbation in metabolic homeostasis, cholesterol metabolism, and mitochondrial functions in response to the obesogenic diet as compared to control mice from a control lineage. This suggests that the continuous intake of long chain n-3 PUFA could be preventive in situations of oversupply of energy-dense, nutrient-poor foods., L'obésité se caractérise par de profondes altérations de la biologie du tissu adipeux (TA), entraînant des troubles métaboliques de l'ensemble du corps tels que la résistance à l'insuline et les maladies cardiovasculaires. Ces altérations sont liées au développement d'une inflammation locale, d'une fibrose, d'une hypertrophie des adipocytes et d'un dérèglement de l'homéostasie énergétique, notamment du tissu adipeux viscéral (TVA). Les acides gras oméga 3 (n-3) (AF) ont été décrits comme possédant des effets bénéfiques contre les troubles liés à l'obésité, y compris dans l'AT ; cependant, l'effet à long terme à travers les générations reste inconnu. La présente étude a été menée pour identifier si une supplémentation en AG polyinsaturés n-3 (AGPI) pendant trois générations pouvait protéger des conséquences d'un régime obésogène dans le VAT. Des jeunes souris de la troisième génération d'une lignée recevant une supplémentation quotidienne (1% de l'alimentation) avec de l'huile de poisson riche en acide eicosapentaénoïque (EPA) ou une quantité isocalorique d'huile de tournesol, ont été nourries avec une alimentation riche en graisses et en sucre. pendant 4 mois. Nous explorons les adaptations transcriptomiques dans chaque lignée à l'aide de puces à ADN dans VAT et l'exploration bioinformatique des régulations biologiques à l'aide de bases de données en ligne. L'apport transgénérationnel d'EPA a conduit à une activation réduite des processus inflammatoires, une perturbation de l'homéostasie métabolique, du métabolisme du cholestérol et des fonctions mitochondriales en réponse au régime obésogène par rapport aux souris témoins d'une lignée témoin. Cela suggère que l'apport continu d'AGPI n-3 à longue chaîne pourrait être préventif dans les situations d'offre excédentaire d'aliments riches en énergie et pauvres en nutriments. ont été nourris avec un régime riche en graisses et en sucre pendant 4 mois. Nous explorons les adaptations transcriptomiques dans chaque lignée à l'aide de puces à ADN dans VAT et l'exploration bioinformatique des régulations biologiques à l'aide de bases de données en ligne. L'apport transgénérationnel d'EPA a conduit à une activation réduite des processus inflammatoires, une perturbation de l'homéostasie métabolique, du métabolisme du cholestérol et des fonctions mitochondriales en réponse au régime obésogène par rapport aux souris témoins d'une lignée témoin. Cela suggère que l'apport continu d'AGPI n-3 à longue chaîne pourrait être préventif dans les situations d'offre excédentaire d'aliments riches en énergie et pauvres en nutriments. ont été nourris avec un régime riche en graisses et en sucre pendant 4 mois. Nous explorons les adaptations transcriptomiques dans chaque lignée à l'aide de puces à ADN dans VAT et l'exploration bioinformatique des régulations biologiques à l'aide de bases de données en ligne. L'apport transgénérationnel d'EPA a conduit à une activation réduite des processus inflammatoires, une perturbation de l'homéostasie métabolique, du métabolisme du cholestérol et des fonctions mitochondriales en réponse au régime obésogène par rapport aux souris témoins d'une lignée témoin. Cela suggère que l'apport continu d'AGPI n-3 à longue chaîne pourrait être préventif dans les situations d'offre excédentaire d'aliments riches en énergie et pauvres en nutriments. L'apport transgénérationnel d'EPA a conduit à une activation réduite des processus inflammatoires, une perturbation de l'homéostasie métabolique, du métabolisme du cholestérol et des fonctions mitochondriales en réponse au régime obésogène par rapport aux souris témoins d'une lignée témoin. Cela suggère que l'apport continu d'AGPI n-3 à longue chaîne pourrait être préventif dans les situations d'offre excédentaire d'aliments riches en énergie et pauvres en nutriments. L'apport transgénérationnel d'EPA a conduit à une activation réduite des processus inflammatoires, une perturbation de l'homéostasie métabolique, du métabolisme du cholestérol et des fonctions mitochondriales en réponse au régime obésogène par rapport aux souris témoins d'une lignée témoin. Cela suggère que l'apport continu d'AGPI n-3 à longue chaîne pourrait être préventif dans les situations d'offre excédentaire d'aliments riches en énergie et pauvres en nutriments.

International audience

BACKGROUND The effects of a dietary supplementation with the vegetable omega-3 α-linolenic acid (ALA) on cardiovascular homeostasis are unclear. In this context, it would be interesting to assess the effects of camelina oil. OBJECTIVE This study aimed to assess the cardiovascular and metabolic effects of camelina oil in hypertensive patients with metabolic syndrome. METHODS In a double-blind placebo-controlled randomized study, treated essential hypertensive patients with metabolic syndrome received during 6 months either cyclodextrin-complexed camelina oil containing ≈ 1.5 g ALA/day (n = 40), or an isocaloric placebo (n = 41), consisting in the same quantity of cyclodextrins and wheat starch. Anthropometric data, plasma lipids, glycemia, insulinemia, creatininemia, thiobarbituric acid reactive substances, high-sensitivity C-reactive protein, and n-3, n-6 and n-9 fatty acids in erythrocyte membranes were measured. Peripheral and central blood pressures, arterial stiffness, carotid intima-media thickness and brachial artery endothelium-dependent flow-mediated dilatation and endothelium-independent dilatation were assessed. RESULTS Compared to placebo, camelina oil increased ALA (mean ± SD: 0 ± 0.04 vs. 0.08 ± 0.06%, P

International audience; Purpose The effect of manipulating the fatty acid profile of the diet over generations could affect the susceptibility to develop obesity and metabolic disorders. Although some acute effects were described, the impact of transgenerational continuous supplementation with omega 3 fatty acids on metabolic homeostasis and skeletal muscle metabolic flexibility during a nutritional stress is unknown. Methods We analyzed the effect of an obesogenic diet in mice after transgenerational supplementation with an omega-3 rich oil (mainly EPA) or a control oil. Young F3 animals received a high fat and high sucrose diet for 4 months. Whole-body biometric data were recorded and lipidomic/transcriptomic adaptations were explored in the skeletal muscle. Results F3 mice from the lineage supplemented with EPA gained less weight, fat mass, and exhibited better metabolic parameters after the obesogenic diet compared to mice from the control lineage. Transcriptomic exploration of skeletal muscle showed differential regulation of biological processes such as fibrosis, fatty acid catabolism, and inflammation between lineages. These adaptations were associated to subtle lipid remodeling of cellular membranes with an enrichment in phospholipids with omega 3 fatty acid in mice from the EPA lineage. Conclusion Transgenerational and continuous intake of EPA could help to reduce cardiovascular and metabolic risks related to an unbalanced diet by the modulation of insulin sensitivity, fatty acid metabolism, and fibrosis in skeletal muscle.

International audience; The purpose of this study was to determine whether magnesium L-lactate is responsible for having a beneficial effect on the myocardium and the skeletal muscles and how this substrate acts at the molecular level. Twenty seven young male Wistar rats were supplied with a magnesium L-lactate (L) solution, a magnesium chloride (M) solution and/or water (W) as a vehicle for 10 weeks. The treated animals absorbed the L and M solutions as they wished since they also had free access to water. After 9 weeks of treatment, in vivo cardiac function was determined ultrasonically. The animals were sacrificed at the end of the tenth week of treatment and the heart was perfused according to the Langendorff method by using a technique allowing the determination of cardiomyocyte activity (same coronary flow in the two groups). Blood was collected and skeletal muscles of the hind legs were weighed. The myocardial expressions of the sodium/proton exchange 1 (NHE1) and sodium/calcium exchange 1 (NCX1), intracellular calcium accumulation, myocardial magnesium content, as well as systemic and tissue oxidative stress, were determined. Animals of the L group absorbed systematically a low dose of L-lactate (31.5 ± 4.3 µg/100 g of body weight/day) which was approximately four times higher than that ingested in the W group through the diet supplied. Ex vivo cardiomyocyte contractility and the mass of some skeletal muscles (tibialis anterior) were increased by the L treatment. Myocardial calcium was decreased, as was evidenced by an increase in total CaMKII expression, without any change in the ratio between phosphorylated CaMKII and total CaMKII. Cardiac magnesium tended to be elevated. Our results suggest that the increased intracellular magnesium concentration was related to L-lactate-induced cytosolic acidosis and to the activation of the NHE1/NCX1 axis. Interestingly, systemic oxidative stress was reduced by the L treatment whereas the lipid profile of the animals was unaltered. Taken together, these results suggest that a chronic low-dose L-lactate intake has a beneficial health effect on some skeletal muscles and the myocardium through the activation of the NHE1/NCX1 axis, a decrease in cellular calcium and an increase in cellular magnesium. The treatment can be beneficial for the health of young rodents in relation to chronic oxidative stress-related diseases.

Insulin resistance decreases the ability of insulin to inhibit hepatic gluconeogenesis, a key step in the development of metabolic syndrome. Metabolic alterations, fat accumulation, and fibrosis in the liver are closely related and contribute to the progression of comorbidities, such as hypertension, type 2 diabetes, or cancer. Omega 3 (n-3) polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), were identified as potent positive regulators of insulin sensitivity in vitro and in animal models. In the current study, we explored the effects of a transgenerational supplementation with EPA in mice exposed to an obesogenic diet on the regulation of microRNAs (miRNAs) and gene expression in the liver using high-throughput techniques. We implemented a comprehensive molecular systems biology approach, combining statistical tools, such as MicroRNA Master Regulator Analysis pipeline and Boolean modeling to integrate these biochemical processes. We demonstrated that EPA mediated molecular adaptations, leading to the inhibition of miR-34a-5p, a negative regulator of Irs2 as a master regulatory event leading to the inhibition of gluconeogenesis by insulin during the fasting&ndash, feeding transition. Omics data integration provided greater biological insight and a better understanding of the relationships between biological variables. Such an approach may be useful for deriving innovative data-driven hypotheses and for the discovery of molecular&ndash, biochemical mechanistic links.

It has been proven that dietary eicosapentaenoic acid (C20:5 n-3 or EPA) protects the heart against the deleterious effects of sepsis in female rats. We do not know if this is the case for male rodents. In this case, the efficiency of other n-3 polyunsaturated fatty acids (PUFAs) remains to be determined in both female and male rats. This study aimed at (i) determining whether dietary EPA is cardioprotective in septic male rats, (ii) evaluating the influence of dietary &alpha, linolenic (C18:3 n-3 or ALA) on cardiac function during this pathology, and (iii) finding out the physiological and molecular mechanisms responsible for the observed effects. Sixty male rats were divided into three dietary groups. The animals were fed a diet deficient in n-3 PUFAs (DEF group), a diet enriched with ALA (ALA group) or a diet fortified with EPA (EPA group) for 6 weeks. Thereafter, each group was subdivided into 2 subgroups, one being subjected to cecal ligation and puncture (CLP) and the other undergoing a fictive surgery. Cardiac function was determined in vivo and ex vivo. Several parameters related to the inflammation process and oxidative stress were determined. Finally, the fatty acid compositions of circulating lipids and cardiac phospholipids were evaluated. The results of the ex vivo situation indicated that sepsis triggered cardiac damage in the DEF group. Conversely, the ex vivo data indicated that dietary ALA and EPA were cardioprotective by resolving the inflammation process and decreasing the oxidative stress. However, the measurements of the cardiac function in the in vivo situation modulated these conclusions. Indeed, in the in vivo situation, sepsis deteriorated cardiac mechanical activity in the ALA group. This was suspected to be due to a restricted coronary flow which was related to a lack of cyclooxygenase substrates in membrane phospholipids. Finally, only EPA proved to be beneficial in sepsis. Its action necessitates both resolution of inflammation and increased coronary perfusion. In that sense, dietary ALA, which does not allow the accumulation of vasodilator precursors in membrane lipids, cannot be protective during the pathology.

[Epub ahead of print]; BACKGROUND & AIMS: Metabolic syndrome (MetS) induces major disturbances in plasma metabolome, reflecting abnormalities of several metabolic pathways. Recent evidences have demonstrated that the consumption of dairy products may protect from MetS, but the mechanisms remains unknown. The present study aimed at identify how the consumption of different types of dairy products could modify the changes in plasma metabolome during MetS. METHODS: In this observational study, we analyzed how the consumption of dairy products could modify the perturbations in the plasma metabolome induced by MetS in a sample of 298 participants (61 with MetS) from the French MONA LISA survey. Metabolomic profiling was analyzed with UPLC-MS/MS. RESULTS: Subjects with MetS exhibited major changes in plasma metabolome. Significant differences in plasma levels of branched chain amino acids, gamma-glutamyl amino acids, and metabolites from arginine and proline metabolism were observed between healthy control and Mets subjects. Plasma levels of many lipid species were increased with MetS (mono- and diacylglycerols, eicosanoids, lysophospholipids and lysoplasmalogens), with corresponding decreases in short chain fatty acids and plasmalogens. The consumption of dairy products, notably with a low fat content (milk and fresh dairy products), altered metabolite profiles in plasma from MetS subjects. Specifically, increasing consumption of dairy products promoted accumulation of plasma C15:0 fatty acid and was inversely associated to some circulating lysophospholipids, sphingolipids, gamma-glutamyl amino acids, leukotriene B4 and lysoplasmalogens. CONCLUSIONS: the consumption of low fat dairy products could mitigate some of the variations induced by MetS.

Epub ahead of print; PURPOSE: To compare the effects of 8-week eccentric (ECC) versus concentric (CON) training using downhill and uphill running in rats on whole body composition, bone mineral density (BMD), and energy expenditure (EE). METHODS: Animals were randomly assigned to one of the following groups: 1) control (CTRL), 2) +15% uphill-running slope (CON), 3) -15% downhill-running slope (ECC15) and 4) -30% downhill-running slope (ECC30). Those programs enabled to achieve conditions of iso-power output for CON and ECC15 and of iso-oxygen uptake (VO2) for CON and ECC30. Trained rats ran 45min at 15 mmin five times per week. Total (TBM), fat (FBM) and lean (LBM) body mass measured through EchoMRI, and 24-hour EE including basal metabolic rate (BMR) assessed using PhenoMaster/LabMaster cage system were obtained before and after training. At sacrifice, the right femur was collected for bone parameters analysis. RESULTS: While TBM increased in all groups over the 8-week period, almost no change occurred for FBM in exercised groups (CON: -4.8+/-6.18 g; ECC15: 0.6+/-3.32 g; ECC30: 2.6+/-6.01 g). The gain in LBM was mainly seen for ECC15 (88.9+/-6.85 g) and ECC30 (101.6+/-11.07 g). ECC was also seen to positively affect BMD. An increase in BMR from baseline was seen in exercise groups (CON: 13.9+/-4.13 kJ.day; ECC15: 11.6+/-5.10 kJ.day; ECC30: 18.3+/-4.33 kJ.day) but not in CTRL one. This difference disappeared when BMR was normalized for LBM. CONCLUSIONS: Results indicate that for iso-VO2 training, the impact on LBM and BMD is enhanced with ECC as compared to CON, and that for iso-power but lower VO2 ECC, an important stimulus for adaptation is still observed. This provides further insights for the use of ECC in populations with cardiorespiratory exercise limitations.

Part of special issue: Abstracts of the 41st ESPEN Congress, Krakow, Poland, 31 August–3 September, 2019; International audience; Rationale: Ectopic lipid deposition impairs muscle anabolic responseespecially during aging. We hypothesized that the anabolic efficiencyof dietary protein in skeletal muscle might be affected by high-fat diet.The objective of the study was to investigate muscle protein synthesisin response totwolevels of protein intake combined totwo levels of fatintake. Methods: Two groups of sixty adult and forty-nine old male Wistarrats were randomly divided into four groups: isocaloric standard diet (12% protein, 14% lipid, as STD12); isocaloric standard (high-protein)diet (25% protein, 14% lipid, STD25); hypercaloric high-fat (normal-protein) diet (12% protein, 45% lipid, HFD12); and hypercaloric high-fat (high-protein) diet (25% protein, 45% lipid, HFD25). The nutritionalintervention lasted 10 weeks. The fractional synthesis (FSR) andabsolute synthesis rates (ASR) of mixed muscle proteins werecalculated using isotopically labelled13C-Valine incorporation intibialis anterior (TA). Muscle lipid content was assessed usingchromatography method. Results: Rats in the high-fat diet groups self-limited their food intake,so that energy intake was not different among the groups. Regardlessof dietary intervention, TAweight was lower in old groups compared totheir adult counterparts (all p values Conclusions: Aging is characterized by reduced muscleweight despiteincreased FSR, suggesting specific alterations in the nutritionalregulation of muscle protein turnover. In isocaloric conditions, higherprotein intake modulates muscle lipid infiltration, without improvingage-related anabolic resistance in old rats fed a high-fat diet.

Diabetes is characterized by a high mortality rate which is often associated with heart failure. Green tea and eicosapentaenoic acid (EPA) are known to lessen some of the harmful impacts of diabetes and to exert cardio-protection. The aim of the study was to determine the effects of EPA, green tea extract (GTE), and a combination of both on the cardiac consequences of diabetes mellitus, induced in Wistar rats by injection of a low dose of streptozotocin (33 mg/kg) combined with a high fat diet. Cardiac mechanical function, coronary reactivity, and parameters of oxidative stress, inflammation, and energy metabolism were evaluated. In the context of diabetes, GTE alone limited several diabetes-related symptoms such as inflammation. It also slightly improved coronary reactivity and considerably enhanced lipid metabolism. EPA alone caused the rapid death of the animals, but this effect was negated by the addition of GTE in the diet. EPA and GTE combined enhanced coronary reactivity considerably more than GTE alone. In a context of significant oxidative stress such as during diabetes mellitus, EPA enrichment constitutes a risk factor for animal survival. It is essential to associate it with the antioxidants contained in GTE in order to decrease mortality rate and preserve cardiac function.

The authors acknowledge the staff from Auvergne University Experimental Animal Laboratory and Christophe Del’Homme, Philippe Denis, Anne Terisse-Lottier and Alexandre Teynie from the Experimental Animal Facility of the Human Nutrition Unit (INRA of Clermont-Ferrand) for their assistance throughout the animal protocol. We thank Celine Bobby for her help for TaqMan gene expression assays. We gratefully acknowledge financial support and doctoral fellowship (to A.P.) fromLesieur and Avril; Impact of ALA, EPA and DHA on obesity and metabolic complications were studied in mice fed a high-fat high-sucrose diet (HF). HF diets were supplemented with ALA, EPA or DHA (1%w/w) and given to C57BL/6J mice for 16 weeks and to Ob/Ob mice for 6 weeks. In C57BL/6J mice, EPA reduced plasma cholesterol (-20%), limited fat mass accumulation (-23%), adipose cell hypertrophy (-50%), and reduced plasma leptin concentration (-60%), compared to HF fed mice. Furthermore, mice supplemented with EPA exhibited a higher insulin sensitivity (+24%) and glucose tolerance (+20%) compared to HF fed mice. Similar effects were observed in EPA supplemented Ob/Ob mice, although fat mass accumulation was not prevented. By contrast in comparison to HF fed mice, DHA did not prevent fat mass accumulation, increased plasma leptin concentration (+128%) in C57BL/6J mice and did not improve glucose homeostasis in C57BL/6J and Ob/Ob mice. In 3T3-L1 adipocytes, DHA stimulated leptin expression whereas EPA induced adiponectin expression, suggesting that improved leptin / adiponectin balance may contribute to the protective effect of EPA. In conclusion, supplementation with EPA, but not ALA and DHA, could preserve glucose homeostasis in an obesogenic environment and limit fat mass accumulation in the early stage of weight gain.

The saturated fatty acid palmitate (PAL) is now recognized as an inducer of inflammation in many types of cells, including adipocytes and muscle cells, whereas n-3 polyunsaturated fatty acids (n-3PUFA) have anti-inflammatory properties. Meanwhile, PAL induces muscle insulin resistance (IR) and n-3PUFA are suggested to reverse it. We investigated n-3PUFA effects on palmitate-induced inflammation and the potential link between inflammation, P38MAPK activation and IR in C2C12 myotubes. After 16 hours incubation with 500µM PAL without or with SB203580, a specific inhibitor of p38MAPK, 50µM of alpha linolenic acid (ALA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), myotubes were harvested and submitted to mRNA quantification or immunoblotting. IL-6, TNF-a and COX-2 mRNA levels were significantly increased by PAL treatment and reversed by EPA and DHA. Inhibition of p38MAPK significantly prevented the effect of PAL on these regulations although it had no significant effect on PAL-induced IR. Additional study should be performed to explore the involvement of NFKB signalling. Our results suggested that p38MAPK activation by PAL is crucial to induce inflammation in C212 muscle cells, independently of IR. Among n-3PUFA, only EPA and DHA reduced p38MAPK activation and improved IR. Additional studies are currently performed to explore the involvement of NFKB signalling in the effect of PAL on myotube inflammation and the impact of n-3 PUFA on this pathway

METABOLISME DES MACRO- ET MICRONUTRIMENTS METABOLISME DES MACRO- ET MICRONUTRIMENTSMETABOLISME DES MACRO- ET MICRONUTRIMENTS; Introduction et but de l’étude: Bien que des études récentes ont démontré que la consommation de produits laitiers peut protéger du syndrome métabolique (MetS), les mécanismes restent méconnus. Dans cette étude observationnelle, nous avons analysé comment la consommation de produits laitiers pouvait modifier les perturbations du métabolome plasmatique induites par le MetS.Matériel et méthodes: Une analyse du métabolome par HPLC-MS/MS et du profil en acides gras par chromatographie gazeuse a été effectuée dans le plasma d'une population de 298 participants (61 avec MetS) de l’étude française MONALISA. L'échantillon a été stratifié en 6 groupes (n=48-53) en fonction du niveau de consommation de produits laitiiers exprimé en portions par jour (4.3. Les comparaisons entre les sujets sains et atteints de MetS ont été faites à l'aide du test du Chi2 pour les variables catégorielles et un test de Student pour les variables continues. Les analyses statistiques des données de métabolomiques ont été faites par des ANOVA à 1 ou 2 voies selon la comparaison avec une prise en compte du taux de faux positif, FDR

Protéines végétales et alimentation durable. journée scientifique de l'UNH

Topic 1 — Inflammation — A Topic 1 — Inflammation — ATopic 1 — Inflammation — A; IntroductionSepsis triggers the failure of cardiac mitochondria and this deleterious effect could be prevented by omega-3 polyunsaturated fatty acids (PUFA).ObjectivesTo evaluate the influence of eicosapentaenoic acid (C20: 5 omega-3 or EPA) on the mechanical and mitochondrial functions of the heart during early sepsis.MethodsFour month-old female Wistar rats were subdivided in 4 groups (n = 8 per group) according to: (i) the 4-week diet given (deficient in omega-3 PUFA [DEF] or enriched with EPA); (ii) the surgery performed (caecal ligation at 1 cm of the apex of the heart and puncture in order to induce sepsis [CLP] or sham). The cardiac mechanical function was studied in vivo by NMR 48 h after the surgery. Immediately after, part of the myocardium was used in order to extract mitochondria and another part was frozen in order to subsequently analyse the fatty acid composition of cardiac phospholipids.ResultsThe EPA groups display a large decrease in the omega-6/omega-3 PUFA ratio of cardiac phospholipids. Sepsis increases the mRNA expression of IL-1beta in the DEF group but not in the EPA one. The mechanical function is altered neither by the diets nor by the surgeries. The DEF/CLP animals have a deficient oxidative phosphorylation compared to the DEF/Sham rats: reduced mitochondrial oxygen consumption (−42%, P < 0.001) and ATP production (−37%, P < 0.05). The sepsis-induced mitochondrial damages in this group is due to an increase reactive oxygen species (ROS) release (+130 and +63% for the ROS/respiration and ROS/ATP ratios, P < 0.01 and P < 0.05, respectively). The dietary EPA prevents these damages (P < 0.05).ConclusionA sufficient EPA intake favours the upholding of the mitochondrial function during early sepsis, which could delay the subsequent development of heart failure. We plan to verify this beneficial effect of EPA in Humans affected by acute endocarditis.

Background and Purpose NO is a crucial regulator of energy and lipid metabolism, whose homeostasis is compromised during obesity. Combination of citrulline and atorvastatin potentiated NO production in vitro. Here we have assessed the effects of this combination in mice with diet-induced obesity (DIO). Experimental Approach C57BL/6J male mice were given a standard diet (control) or a high fat–high sucrose diet (DIO) for 8 weeks. DIO mice were then treated with DIO alone, DIO with citrulline, DIO with atorvastatin or DIO with citrulline and atorvastatin (DIOcit–stat) for 3 weeks. Thereafter, body composition, glucose tolerance, insulin sensitivity and liver fat metabolism were measured. Key Results DIOcit–stat mice showed lower body weight, fat mass and epididymal fat depots compared with other DIO groups. Unlike other DIO groups, glucose tolerance and insulin sensitivity of DIOcit–stat, along with blood glucose and insulin concentrations in response to feeding, were restored to control values. Refeeding-induced changes in liver lipogenic activity were also reduced in DIOcit–stat mice compared with those of DIO animals. This was associated with decreased gene expression of the transcription factor SREBP-1, liver X receptor α, ChREBP and of target lipogenic enzymes in the liver of DIOcit–stat mice compared with those of other DIO groups. Conclusions and Implications The citrulline–atorvastatin combination prevented fat mass accumulation and maintained glucose homeostasis in DIO mice. Furthermore, it potentiated inhibition of hepatic de novo lipogenesis activity. This combination has potential for preservation of glucose homeostasis in patients receiving statin therapy.

International audience; Skeletal muscle plays a major role in the control of whole body glucose disposal in response to insulin stimulus. Excessive supply of fatty acids to this tissue triggers cellular and molecular disturbances leading to lipotoxicity, inflammation, mitochondrial dysfunctions, impaired insulin response and decreased glucose uptake. This study was conducted to analyze the preventive effect of docosahexaenoic acid (DHA), a long-chain polyunsaturated n-3 fatty acid, against insulin resistance, lipotoxicity and inflammation in skeletal muscle at doses compatible with nutritional supplementation. DHA (30 muM) prevented insulin resistance in C2C12 myotubes exposed to palmitate (500 muM) by decreasing protein kinase C (PKC)-theta activation and restoring cellular acylcarnitine profile, insulin-dependent AKT phosphorylation and glucose uptake. Furthermore, DHA protected C2C12 myotubes from palmitate- or lipopolysaccharide-induced increase in Ptgs2, interleukin 6 and tumor necrosis factor-alpha mRNA level, probably through the inhibition of p38 MAP kinase and c-Jun amino-terminal kinase. In LDLR -/- mice fed a high-cholesterol-high-sucrose diet, supplementation with DHA reaching up to 2% of daily energy intake enhanced the insulin-dependent AKT phosphorylation and reduced the PKC-theta activation in skeletal muscle. Therefore, DHA used at physiological doses participates in the regulation of muscle lipid and glucose metabolisms by preventing lipotoxicity and inflammation.

Introduction et but de l’etude Le sepsis est caracterise par une forte mortalite (40–60 %) qui est accompagnee dans la moitie des cas par une defaillance cardiaque. Un dysfonctionnement mitochondrial participerait a cette atteinte. Les acides gras polyinsatures (AGPI) n-3 presentent un role protecteur dans differentes cardiopathies. L’objectif de cette etude est de determiner les effets potentiels d’un AGPI n-3, l’acide eicosapentaenoique (EPA), sur les fonctions mecanique et mitochondriale cardiaques dans un modele de sepsis precoce. Materiel et methodes Apres le sevrage, 32 rates Wistar ont ete reparties en deux groupes de taille similaire selon le regime alimentaire suivi pendant 4 semaines. Ce dernier comportait 5 % de lipides dont 45 % d’acide linoleique. Il consistait soit en un regime carence en AGPI n-3 totaux (CAR) soit en un regime enrichi en EPA a hauteur de 0,625 % de la composition totale. A la fin de cette periode, les animaux de chaque groupe ont ete subdivises en 2 lots : le premier subissant une operation ayant pour but de declencher un sepsis consistant en une ligature et une perforation caecales (SEP) et un second ne subissant qu’une operation fictive sans ligature ni perforation (FIC). La morphologie et la fonction cardiaques ont ete etudiees par IRM 48 h apres l’operation. Les mitochondries cardiaques ont ete extraites afin d’analyser l’oxydation phosphorylante (respiration mitochondriale + production d’ATP) et la liberation des especes reactives de l’oxygene (ERO) avec 3 substrats differents : glutamate-malate (GM), palmitoylcarnitine-malate (PC) et succinate + rotenone (SR). La composition en acides gras des lipides plasmatiques (LP) et des phospholipides cardiaques (PLC) a ete mesuree. Les resultats ont ete analyses par une ANOVA a 2 facteurs. Resultats et analyse statistique Dans le groupe EPA, quelle que soit l’operation subie, l’analyse des acides gras des LP et celle des PLC montrent une importante baisse du rapport AGPI n-6/n-3 (p Conclusion Malgre le maintien de la fonction cardiaque dans ce modele de sepsis precoce, un dysfonctionnement mitochondrial est neanmoins constate dans le groupe CAR. Cette atteinte n’est pas observee dans le groupe EPA. Grâce a cette protection mitochondriale, l’acide gras n-3 pourrait prevenir ou reduire la defaillance cardiaque susceptible de survenir ulterieurement.

This work was supported by 2 grants attributed by the Fédération Française de Cardiologie and society ADETEC of patients with a previous cardiac surgery; If it is sustained for several days, sepsis can trigger severe abnormalities of cardiac function which leads to death in 50% of cases. This probably occurs through activation of toll‐like receptor‐9 by bacterial lipopolysaccharides and overproduction of proinflammatory cytokines such as TNF‐α and IL‐1β. In contrast, early sepsis is characterized by the development of tachycardia. This study aimed at determining the early changes in the cardiac function during sepsis and at finding the mechanism responsible for the observed changes. Sixty male Wistar rats were randomly assigned to two groups, the first one being made septic by cecal ligation and puncture (sepsis group) and the second one being subjected to the same surgery without cecal ligation and puncture (sham‐operated group). The cardiac function was assessed in vivo and ex vivo in standard conditions. Several parameters involved in the oxidative stress and inflammation were determined in the plasma and heart. As evidenced by the plasma level of TNF‐α and gene expression of IL‐1β and TNF‐α in the heart, inflammation was developed in the sepsis group. The cardiac function was also slightly stimulated by sepsis in the in vivo and ex vivo situations. This was associated with unchanged levels of oxidative stress, but several parameters indicated a lower cardiac production of reactive oxygen species in the septic group. In conclusion, despite the development of inflammation, early sepsis did not increase reactive oxygen species production and did not reduce myocardial function. The depressant effect of TNF‐α and IL‐1β on the cardiac function is known to occur at very high concentrations. The influence of low‐ to moderate‐grade inflammation on the myocardial mechanical behavior must thus be revisited.

We gratefully acknowledge financial support from Avril (23000596) for the PhD thesis of A. Pinel and our research. We also thank Lesieur for their scientific support; Excessive energy intake leads to fat overload and the formation of lipotoxic compounds mainly derived from the saturated fatty add palmitate (PAL), thus promoting insulin resistance (IR) in skeletal muscle. N-3 polyunsaturated fatty acids (n - 3PUFA) may prevent lipotoxicity and IR. The purpose of this study was to examine the differential effects of n 3PUFA on fatty acid metabolism and insulin sensitivity in muscle cells. C2C12 myotubes were treated with 500 mu M of PAL without or with 50 mu M of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) for 16h. PAL decreased insulin-dependent AKT activation and glucose uptake and increased the synthesis of ceramides and diglycerides (DG) derivatives, leading to protein kinase CO activation. EPA and DMA, but not ALA, prevented PAL-decreased AKT activation but glucose uptake was restored to control values by all n 3PUFA vs. PAL. Total DG and ceramide contents were decreased by all n 3PUFA, but only EPA and DMA increased PAL beta-oxidation, decreased PAL incorporation into DG and reduced protein kinase CO activation. EPA and DMA emerge as better candidates than ALA to improve fatty acid metabolism in skeletal muscle cells, notably via their ability to increase mitochondrial beta-oxidation

Abdominal obesity increases the incidence of cardiac events but reduces mortality when one of these events occurs. The phenomenon called obesity paradox might be related to myocardial energetics. This study was aimed at determining whether long-term abdominal adiposity alters cardiac energy function. Two groups of male Wistar rats were fed a standard or a Western-type (WD) diet for 8 months. The ex vivo coronary reactivity and mechanical function as well as the mitochondrial oxidative phosphorylation (mOxPhos) and hydrogen peroxide release (mH2O2r) were determined. Abdominal adiposity was augmented by the WD. This was also the case for the coronary reactivity to acetylcholine, but the rate pressure product remained roughly stable despite a reduction of the left ventricle-developed pressure partly compensated by a slight increase in heart rate. The prolonged WD administration resulted in an improvement of mOxPhos, but the mH2O2r was exaggerated which was confirmed in the whole cell by a reduced aconitase to fumarase ratio. This did not modify the plasma oxidative stress due to an increased plasma antioxidant status. In conclusion, long-term WD administration improved the cardiac fitness and might predispose the organism to the obesity paradox. Conversely, the increased mitochondrial mH2O2r can precipitate the heart toward cardiomyopathy if the WD is maintained for a longer duration.

International audience; Background: The 2 major dietary sources of trans fatty acids (TFAs) are partially hydrogenated oils and ruminant-derived products. Epidemiologic data suggest that chronic consumption of industrial sources of TFAs could be damaging to insulin sensitivity, but intervention studies on this issue have remained inconclusive. Objective: The trial was designed to compare the effects of dairy compared with industrial sources of TFAs on insulin sensitivity in overweight women. Design: Sixty-three healthy women with abdominal obesity [waist circumference > 88 cm and a body mass index (in kg/m(2)) > 28] were recruited. After a run-in period, the volunteers were randomly assigned to consume 1 of 3 four-week diets: 60 g low-TFA lipids/d (0.54 g/d; n = 21), ruminant TFA-rich lipids (4.86 g/d; n = 21), or industrial TFA-rich lipids (5.58 g/d; n = 21). Changes in peripheral insulin sensitivity were assessed by using hyperinsulinemiceuglycemic clamps. Results: After the intervention period, fasting glycemia and insulinemia and insulin sensitivity were not significantly modified in either group (P > 0.05). Conclusions: These data indicate that consumption of dairy- and industrial-source TFAs for 4 wk at nutritional levels do not impair peripheral insulin sensitivity in insulin-resistant women. Our study may not preassess the effects of TFAs in normal insulin-sensitive individuals. This trial was registered at clinicaltrials.gov as NCT00617435. Am J Clin Nutr 2009;90:88-94.

International audience; Epidemiological studies suggest that chronic consumption of trans MUFA may alter muscle insulin sensitivity. The major sources of dietary trans MUFA (dairy fat vs. industrially hydrogenated oils) have different isomeric profiles and thus probably different metabolic consequences. These effects may involve alterations in muscle mitochondrial oxidative capacity, which may in turn promote insulin resistance if fatty acid oxidation is reduced. We report that in Wistar rats, an 8 week diet enriched (4% of energy intake) in either dairy, industrial, or control MUFA did not alter insulin and glucose responses to an intraperitoneal glucose tolerance test (1g/kg). In C2C12 myotubes, vaccenic and elaidic acids did not modify insulin sensitivity compared with oleic acid. Furthermore, the ex vivo total, mitochondrial and peroxisomal oxidation rates of [1-(14)C]oleic, vaccenic, and elaidic acids were similar in soleus and tibialis anterior rat muscle. Finally, an 8 week diet enriched in either dairy or industrial trans MUFA did not alter mitochondrial oxidative capacity in these two muscles compared with control MUFA but did induce a specific reduction in soleus mitochondrial ATP and superoxide anion production (P

Introduction et but de l’etude La sarcopenie associee a une obesite represente un facteur de risque pour l’etat de sante des personnes âgees. Ce phenotype defini sous le terme d’obesite sarcopenique a ete reproduit dans un modele de rats âges soumis durant 10 semaines a un regime hyperlipidique–hypercalorique. Une resistance de l’anabolisme proteique musculaire est observee, associee a une alteration des capacites oxydatives mitochondriales, et cela de maniere plus prononcee que chez des rats âges nourris avec un regime standard [1] . Les apports nutritionnels peuvent moduler ce phenotype puisque les niveaux d’apports proteiques influencent l’anabolisme proteique. Le but de cette etude etait de determiner si des apports proteiques eleves au sein d’un regime inducteur d’obesite pourraient prevenir les alterations musculaires induites par le regime hyperlipidique. Materiel et methodes Des rats âges de 19 mois ont ete soumis durant 10 semaines a un regime hyperlipidique–hypercalorique (HFD) ou standard (STD) associe a des apports proteiques moderes (12 % de l’apport energetique total [AET ; STD12, HFD12] ou eleves (25 % de l’AET ; STD25, HFD25). La composition corporelle des animaux a ete analysee par echoMRI au debut et a la fin du regime. Des evaluations de force et de puissance musculaire ont ete realisees in vivo avec un dynamometre isocinetique en meme temps. Les activites enzymatiques mitochondriales (hydroxyacyl-CoA-deshydrogenase [HAD], citrate synthase [CS] et cytochrome C oxydase [COX]) ont ete mesurees par spectrophotometrie. Resultats et analyse statistique Au bout de 10 semaines de regime, la variation de masse grasse etait significativement plus elevee dans les groupes HFD (HFD25 : + 103,5 ± 33,0 g ; HFD12 : + 113,5 ± 31,6 g) que dans les groupes STD (STD25 : + 41,2 ± 20,8 g ; STD12 : + 60,5 ± 32,4 g ; p Tableau 1 ). Conclusion Chez le rat âge, l’effet benefique des proteines alimentaires sur l’anabolisme et le metabolisme musculaire n’est pas retrouve en situation de surnutrition lipidique, suggerant un etat de resistance anabolique induit par l’obesite.

On that occasion, the two French societies dedicated to lipid science and technology, GERLI and SFEL, will combine their efforts to assist the scientific committee to establish an attractive program for the Euro Fed Lipid congress.On that occasion, the two French societies dedicated to lipid science and technology, GERLI and SFEL, will combine their efforts to assist the scientific committee to establish an attractive program for the Euro Fed Lipid congress.; Since few decades, incidence of obesity and type 2 diabetes (T2D) is increasing. Excessive intake of energy leads to fat overload and formation of lipotoxic compounds mainly derived from the saturated fatty acid palmitate in insulin-sensitive tissues (muscle, liver and white adipose tissue), promoting insulin resistance (IR, a well-known metabolic disorder in T2D). Supplementation with n-3 fatty acids (n-3FA) is suggested to reduce lipotoxicity and IR. We hypothesized that, according to the n-3FA used, differential and specific effects on palmitate metabolism in muscle cells will be demonstrated. C2C12 myotubes were treated with 500 µM of palmitate without or with 50 µM of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) for 16 hours and collected for measurement of membrane fluidity using diphenyl-hexatriene, ceramide content, insulin-dependent Akt protein phosphorylation (as an index of IR). The assessment of the intracellular metabolism and incorporation of palmitate into lipid fractions (triglycerides, phospholipids, diglycerides) was performed after treatment for 3 hours with [1-14C]-palmitate. As expected, palmitate-induced IR was restored by EPA and DHA supplementation whereas ALA had no effect compared to palmitate alone. EPA and DHA significantly improved C2C12 membrane fluidity compared to palmitate alone (+8.5% and +13% respectively, p

National audience

International audience; BACKGROUND: Saturated fatty acid-rich high fat (HF) diets trigger abdominal adiposity, insulin resistance, type 2 diabetes and cardiac dysfunction. This study was aimed at evaluating the effects of nascent obesity on the cardiac function of animals fed a high-fat diet and at analyzing the mechanisms by which these alterations occurred at the level of coronary reserve. MATERIALS AND METHODS: Rats were fed a control (C) or a HF diet containing high proportions of saturated fatty acids for 3 months. Thereafter, their cardiac function was evaluated in vivo using a pressure probe inserted into the cavity of the left ventricle. Their heart was isolated, perfused iso-volumetrically according to the Langendorff mode and the coronary reserve was evaluated by determining the endothelial-dependent (EDV) and endothelial-independent (EIV) vasodilatations in the absence and presence of endothelial nitric oxide synthase and cyclooxygenase inhibitors (L-NAME and indomethacin). The fatty acid composition of cardiac phospholipids was then evaluated. RESULTS: Although all the HF-fed rats increased their abdominal adiposity, some of them did not gain body weight (HF- group) compared to the C group whereas other ones had a higher body weight (HF+). All HF rats displayed a higher in vivo cardiac activity associated with an increased EDV. In the HF- group, the improved EDV was due to an increase in the endothelial cell vasodilatation activity whereas in the HF+ group, the enhanced EDV resulted from an improved sensitivity of coronary smooth muscle cells to nitric oxide. Furthermore, in the HF- group the main pathway implicated in the EDV was the NOS pathway while in the HF+ group the COX pathway. CONCLUSIONS: Nascent obesity-induced improvement of cardiac function may be supported by an enhanced coronary reserve occurring via different mechanisms. These mechanisms implicate either the endothelial cells activity or the smooth muscle cells sensitivity depending on the body adiposity of the animals.

Long-chain (LC)n-3 PUFA have a broad range of biological properties that can be achieved at the gene expression level. This has been well described in liver, where LCn-3 PUFA modulate the expression of genes related to lipid metabolism. However, the complexity of biological pathway modulations and the nature of bioactive molecules are still under investigation. The present study aimed to investigate the dose–response effects of LCn-3 PUFA on the production of peroxidised metabolites, as potential bioactive molecules, and on global gene expression in liver. Hypercholesterolaemic rabbits received by daily oral administration (7 weeks) either oleic acid-rich oil or a mixture of oils providing 0·1, 0·5 or 1 % (groups 1, 2 and 3 respectively) of energy as DHA. Levels of specific peroxidised metabolites, namely 4-hydroxyhexenal (4-HHE)–protein adducts, issued from LCn-3 PUFA were measured by GC/MS/MS in liver in parallel to transcription profiling. The intake of LCn-3 PUFA increased, in a dose-dependent manner, the hepatic production of 4-HHE. At the highest dose, LCn-3 PUFA provoked an accumulation of TAG in liver, which can be directly linked to increased mRNA levels of lipoprotein hepatic receptors (LDL-receptor and VLDL-receptor). In groups 1 and 2, the mRNA levels of microsomal TAG transfer protein decreased, suggesting a possible new mechanism to reduce VLDL secretion. These modulations of genes related to lipoprotein metabolism were independent of PPARα signalling but were probably linked to the activation of the farnesol X receptor pathway by LCn-3 PUFA and/or their metabolites such as HHE.

The major whey proteins IgG, serum albumin and alpha-lactalbumin were purified from camel milk using gel permeation and ion-exchange chromatography. Specific antisera against each of them were raised and used to quantify their heat denaturation in early or mature milk over a range of 60-90 degrees C for 10-60 min using the single radial immunodiffusion technique. The heat denaturation midpoints for the mature milk heated 30 min were 67(.)2, 73(.)0 and 77(.)5 degrees C for IgG, albumin and alpha-lactalbumin respectively. The early milk was more sensitive to heat treatment with coagulation at low temperature and heat denaturation midpoints of 64(.)8, 71(.)6 and 72(.)6 degrees C respectively. This difference was related to the high IgG content of the early milk (12(.)6 mg/ml v. 0(.)5 mg/ml for the mature milk) and stresses the importance of monitoring the IgG level of milk to assess the absence of colostrum.

Introduction et but de l’etude Depuis plusieurs decennies, l’obesite et le diabete de type 2 sont au centre des politiques de sante publique. L’exces d’apport energetique induit une surcharge cellulaire en composes lipotoxiques (ceramides, diglycerides) derives du palmitate, un acide gras sature. La lipotoxicite engendree participe a l’apparition d’une insulino-resistance, particulierement frequente dans le syndrome metabolique et le diabete de type 2. Une supplementation en acides gras omega-3 pourrait etre favorable a une baisse de la lipotoxicite et de l’insulino-resistance (IR). Nous avons pose l’hypothese que selon l’omega-3 utilise, des effets specifiques sur le metabolisme du palmitate seront observables. Materiel et methodes Des myotubes de la lignee C2C12 ont ete traites avec 500 μ M de palmitate, sans ou avec 50 μ M d’acide alpha-linoleique (ALA), eicosapentaenoique (EPA) ou docosa-hexaenoique (DHA) pendant 16 h et collectees pour des mesures de fluidite membranaire, de concentration en ceramides et de phospho-rylation insulino-dependante de la proteine Akt (comme indice d’IR). L’exploration du metabolisme du palmitate et son incorporation dans les differentes fractions lipidiques (triglycerides, diglycerides, phospholipides) a ete menee apres traitement pendant 3 h au palmitate radioactif ([1- 14 C] palmitate). Resultats et Analyse statistique L’insulino-sensibilite, reduite par le palmitate, est restauree par les supplementations en EPA et en DHA mais pas par l’ALA. L’EPA et le DHA ameliorent significati-vement la fluidite membranaire compares au palmitate seul. De plus, l’accumulation de ceramides induite par le palmitate est signi-ficativement reduite par les trois omega-3, avec une efficacite superieure de l’EPA. L’incorporation du palmitate dans les diglycerides est reduite significativement par la supplementation en EPA et en DHA. L’ALA active la proteine kinase C theta inhibitrice de la voie de l’insuline, mais egalement la kinase p38 dont le role reste a elucider. Au contraire, l’EPA et le DHA n’activent pas ses voies. Conclusion En conclusion, et contrairement a l’ALA, les traitements a l’EPA et au DHA restaurent l’activite de la voie de signalisation de l’insuline en modulant la fluidite membranaire et le metabolisme du palmitate, demontrant ainsi que les omega-3 ont des effets differentiels sur le metabolisme lipidique des cellules musculaires C2C12.

Introduction et but de l’etude Les statines ont ete associees a une augmentation du risque de diabete de type 2. L’association de la citrulline a l’atorvastatine permettrait de potentialiser la production de monoxyde d’azote (NO) dans les cellules endotheliales (1), le NO etant un regulateur central du metabolisme energetique et de la sensibilite a l’insuline. Notre objectif a donc ete d’examiner les benefices sante de la combinaison citrulline-atorvastatine dans un modele murin d’obesite et de resistance a l’insuline d’origine nutri-tionnelle. Materiel et methodes Des souris mâles C57BL/6J (n=160) ont recu pendant 12 semaines un regime standard (STD) ou un regime riche en graisses et en sucre (HE, hyper-energetique). Au cours des 3 dernieres semaines d’intervention, 4 groupes HE ont ete constitues pour recevoir HE seul, ou enrichi en citrulline (2,5 g/kg) (HEcit), ou en atorvastatine (10 mg/kg) (HEstat) ou en la combinaison des deux (HEcit-stat). La composition corporelle, la tolerance au glucose, la sensibilite a l’insuline et le metabolisme lipidique hepatique ont ete examines en fin d’experimentation. L’effet des traitements a ete teste par analyse de la variance (ANOVA) a un facteur a l’aide du logiciel Statview (SAS Institute, USA). Lorsque l’analyse etait significative, un test de Fisher etait realise pour analyser les differences deux a deux. Les differences ont ete considerees significatives a p Resultats et Analyse statistique Seul HEcit-stat a permis d’ameliorer le poids corporel (−4 %), la masse grasse (−29 %), la tolerance au glucose (+85 %) et la sensibilite a l’insuline (+30 %) par rapport aux autres groupes HE (p Conclusion La combinaison citrulline-atorvastatine reduit le stockage adipeux et retablit l’homeostasie glucidique de souris recevant un regime HE. En outre, Elle potentialise l’activation de l’AMPK dans le foie, limitant ainsi l’activite lipogenique. Elle ouvre ainsi des perspectives prometteuses pour le traitement de l’obesite et le diabete de type 2.

Introduction et but de l’etude Les metabolismes lipidiques et energetiques sont intrinsequement lies et jouent un role central dans l’apparition de la resistance a l’insuline dans le muscle squelettique. Ce phenomene implique notamment le stress oxydant, l’inflammation et/ou une lipotoxicite qui sont eux-memes influences par le degre de saturation et les taux cellulaires et circulant d’acides gras et de leurs metabolites. Il est bien connu que les acides gras satures (AGS) favorisent la resistance a l’insuline. En s’opposant a certains effets des AGS, les acides gras polyinsatures n-3 a longue chaine (AGPI n-3-LC) seraient protecteurs contre l’insulinoresistance. Les relations entre les mecanismes de transport des acides gras, la signalisation de l’insuline et le metabolisme musculaire sont mal connues. Materiel et methodes Nous avons analyse les effets d’un AGPI n-3-LC, le DHA (30 μ M) sur la cellule musculaire de type C2C12 traitee au palmitate (500 μ M). La sensibilite a l’insuline a ete evaluee par la quantification de la phosphorylation de la proteine Akt (Western-Blot) et la captation de glucose (Glucose uptake cell-based assay, Cayman). La lipotoxicite a ete quantifie par la mesure des taux d’acyl carnitines et de ceramides (spectrometrie de masse), la phoshorylation de la PKC-9 (Western-Blot) et l’expression de cytokines pro-inflammatoire (RT-qPCR). Resultats et Analyse statistique Le DHA s’oppose aux effets deleteres du palmitate vis a vis de la sensibilite a l’insuline des myotubes C2C12. Il permet de normaliser la signalisation cellulaire et la captation de glucose. L’elevation du taux cellulaire en ceramides est associee a une activation de la PKC-9,. A l’inverse, l’inhibition de la synthese des ceramides par la myriocine attenue cet effet et restaure partiellement l’insulinosensibilite. Le profil cellulaire en acyl carnitines est modifie en presence de palmitate suggerant une moindre efficacite de la [3-oxydation. Ce profil est restaure en presence de DHA, suggerant une normalisation du fonctionnement de la (3-oxydation par cet AGPI n-3-LC. Ce resultat est confirme par une amelioration des taux d’ARNm des Cpt1a et 1b. En outre, le DHA reduit les niveaux d’expression des mediateurs pro-inflammatoires TNFα, IL6 et Ptgs2 qui sont fortement augmentes par le palmitate. Conclusion Nous montrons la premiere fois un effet benefique du DHA sur l’insulinosensibilite musculaire a une dose physiologique. Cet AG regule favorablement la lipotoxicite induite par un AGS en regulant les teneurs cellulaires en ceramides et en reprimant les processus inflammatoires et l’activation de la PKC-θ. Ces effets sont associes a des signes de meilleur fonctionnement de la (3-oxydation des acides gras.

Introduction et but de l’etude Le vieillissement est caracterise par une accumulation et une redistribution de la masse grasse corporelle avec une augmentation importante des depots adipeux intra-abdominaux. Ce phenomene pourrait contribuer aux perturbations de l’accretion proteique musculaire liees a l’âge, en particulier chez le sujet âge obese, debouchant sur le syndrome d’obesite sarcopenique. L’objectif de cette etude etait d’evaluer, chez le rat jeune ou âge, l’effet de l’accroissement de l’adiposite par un regime hyper-lipidique et hyper-calorique (HL), sur la production de cytokines pro- et anti-inflammatoires, l’insulino-sensibilite (IoS) et la vitesse de synthese des proteines musculaires et adipeuses (FSR). Materiel et methodes 34 rats Wistar mâles âges de 6 (J) ou 25 (V) mois ont ete repartis en 4 groupes et ont recu un regime normo-(JNL, VNL) ou hyper-lipidique/hyper-calorique (JHL, VHL) durant 10 semaines. Un test de tolerance au glucose (IPGTT) a ete realise afin d’evaluer l’IoS. Le profil inflammatoire a ete evalue en mesurant la concentration plasmatique (ELISA) du recepteur soluble du TNFa (sTNF-R2) et la quantite d’ARNm (qRT-PCR) de l’adiponectine dans le tissu adipeux. Le FSR a ete calcule a partir de l’enrichissement en [13C] valine des proteines musculaires (tibialis anterior) et adipeuses (tissu adipeux abdominal) par spectrometrie de masse. Resultats L’IoS etait diminuee chez les vieux rats soumis a un regime HL (VHF vs VNL, JNL, JHF ; p Conclusions L’augmentation de l’adiposite chez les rats âges induite par le regime HL s’accompagne d’une augmentation de l’inflammation, d’une insulinoresistance, et d’une reduction de la synthese proteique musculaire. Ce defaut d’adaptation du metabolisme proteique preferentiellement musculaire en reponse au regime HL pourrait participer a l’acceleration de la perte proteique musculaire et favoriser l’apparition d’une obesite sarcopenique.

We would like to thank Mr. Cristophe Cottet for carefully editing the manuscript, Cindy Tellier for animal care, Mireille Osman for the measurements of GPx activity, FRAP assay and thiol groups in the plasmaWe would like to thank Mr. Cristophe Cottet for carefully editing the manuscript, Cindy Tellier for animal care, Mireille Osman for themeasurements of GPx activity, FRAP assay and thiol groups in the plasma; Background: There has been accumulating evidence associating diabetes mellitus and cardiovascular dysfunctions. However, most of the studies are focused on the late stages of diabetes and on the function of large arteries. This study aimed at characterizing the effects of the early phase of diabetes mellitus on the cardiac and vascular function with focus on the intact coronary microvasculature and the oxidative stress involved. Materials and methods: Zucker diabetic fatty rats and their lean littermates fed with standard diet A04 (Safe) were studied at the 11th week of age. Biochemical parameters such as glucose, insulin and triglycerides levels as well as their oxidative stress status were measured. Their hearts were perfused ex vivo according to Langendorff and their cardiac activity and coronary microvascular reactivity were evaluated. Results: Zucker fatty rats already exhibited a diabetic state at this age as demonstrated by the elevated levels of plasma glucose, insulin, glycated hemoglobin and triglycerides. The ex vivo perfusion of their hearts revealed a decreased cardiac mechanical function and coronary flow. This was accompanied by an increase in the overall oxidative stress of the organs. However, estimation of the active form of endothelial nitric oxide synthase and coronary reactivity indicated a preserved function of the coronary microvessels at this phase of the disease. Diabetes affected also the cardiac membrane phospholipid fatty acid composition by increasing the arachidonic acid and n-3 polyunsaturated fatty acids levels. Conclusions: The presence of diabetes, even at its beginning, significantly increased the overall oxidative stress of the organs resulting to decreased cardiac mechanical activity ex vivo. However, adaptations were adopted at this early phase of the disease regarding the preserved coronary microvascular reactivity and the associated cardiac phospholipid composition in order to provide a certain protection to the heart

Introduction L’insulino-resistance (IR) associee a l’obesite et au vieillissement, pourrait participer a l’acceleration des anomalies fonctionnelles au niveau musculaire, debouchant ainsi sur la mise en place d’une obesite sarcopenique. En effet, il a ete montre que l’insuline augmente les vitesses de synthese proteique (FSR) musculaire. L’objectif etait d’evaluer, chez le rat jeune ou âge l’effet de l’accroissement de l’adiposite par un regime hyper-lipidique et hyper-calorique (HL), sur la production de cytokines pro-inflammatoires, l’insulino-sensibilite (IoS) et la vitesse de synthese des proteines musculaires. Materiels et methodes 34 rats âges de 6 (J) ou 25 (V) mois repartis en 4 groupes, ont recu un regime normo-lipidique (JNL, VNL) ou HL (JHL, VHL) durant 10 semaines. L’inflammation, la sensibilite a l’insuline ainsi que les FSR musculaires ont ete mesurees. Resultats Le regime HL a entraine une moindre augmentation (p vs VNL) comparativement au rat jeune (+ 80 % ; p vs JNL). L’IR et le statut inflammatoire sont augmentes dans le groupe VHL (VHL vs VNL, JNL, JHL ; p vs VNL ; p Conclusion Le regime HL a donc induit une inflammation et une insulinoresistance uniquement chez le rat âge, entrainant une reduction de la proteosynthese musculaire. Il nous reste a caracteriser les dysfonctionnements du tissu adipeux chez le vieux rat et leurs roles dans le dialogue entre le muscle squelettique et ce tissu.

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