RESUMO
BACKGROUND AND AIMS: TOTUM-63, a fibre and polyphenol rich plant-based composition, has been demonstrated to significantly improve body weight and glucose homeostasis in animal models of obesity. Our study aimed at exploring whether the mechanisms include modulation of gut (glucose-dependent insulinotropic peptide (GIP), glucagon-like petide-1 (GLP-1), cholecystokinin (CCK), peptide YY (PYY)) and pancreatic (insulin, glucagon) hormones, all important regulators of glucose control, appetite and body weight. METHODS AND RESULTS: Male C57BL/6JRJ mice were assigned to either standard chow (CON), high fat diet (HF, 60% energy from fat) or HF-TOTUM-63 (HF diet 60% supplemented with TOTUM-63 2.7%) for 10 weeks. In vivo glucose homeostasis (oral glucose tolerance test (OGTT), intraperitoneal pyruvate tolerance test (ipPTT)), glucose-induced portal vein hormone concentration, gut hormone gene expression and protein content as well as enteroendocrine cell contents were assessed at the end of the dietary intervention. The present study evidenced that TOTUM-63 reduced food intake, limited weight gain and improved glucose and pyruvate tolerance of HF-fed animals. This was associated with an increase in PYY content in the colon, an altered pattern of PYY secretion between fasted and glucose-stimulated states, and with a significant improvement in the portal vein concentration of GLP-1, insulin and glucagon, but not GIP and CCK, in response to glucose stimulation. CONCLUSION: Overall, these data suggest that TOTUM-63 might have a specific impact on gut L-cells and on the expression and secretion of GLP-1 and PYY incretins, potentially contributing to the reduced food intake, body weight gain and improved glucose homeostasis.
Assuntos
Glucagon , Extratos Vegetais/farmacologia , Polifenóis , Animais , Glicemia/metabolismo , Peso Corporal , Dieta Hiperlipídica , Polipeptídeo Inibidor Gástrico , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Humanos , Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Peptídeo YY , Polifenóis/farmacologia , Piruvatos , Aumento de PesoRESUMO
BACKGROUND: Soybean lecithin, a plant-based emulsifier widely used in food, is capable of modulating postprandial lipid metabolism. With arising concerns of sustainability, alternative sources of vegetal lecithin are urgently needed, and their metabolic effects must be characterized. OBJECTIVES: We evaluated the impact of increasing doses of rapeseed lecithin (RL), rich in essential α-linolenic acid (ALA), on postprandial lipid metabolism and ALA bioavailability in lymph-cannulated rats. METHODS: Male Wistar rats (8 weeks old) undergoing a mesenteric lymph duct cannulation were intragastrically administered 1 g of an oil mixture containing 4% ALA and 0, 1, 3, 10, or 30% RL (5 groups). Lymph fractions were collected for 6 h. Lymph lipids and chylomicrons (CMs) were characterized. The expression of genes implicated in intestinal lipid metabolism was determined in the duodenum at 6 h. Data was analyzed using either sigmoidal or linear mixed-effects models, or one-way ANOVA, where appropriate. RESULTS: RL dose-dependently increased the lymphatic recovery (AUC) of total lipids (1100 µg/mL·h per additional RL%; P = 0.010) and ALA (50 µg/mL·h per additional RL%; P = 0.0076). RL induced a faster appearance of ALA in lymph, as evidenced by the exponential decrease of the rate of appearance of ALA with RL (R2 = 0.26; P = 0.0064). Although the number of CMs was unaffected by RL, CM diameter was increased in the 30%-RL group, compared to the control group (0% RL), by 86% at 3-4 h (P = 0.065) and by 81% at 4-6 h (P = 0.0002) following administration. This increase was positively correlated with the duodenal mRNA expression of microsomal triglyceride transfer protein (Mttp; ρ= 0.63; P = 0.0052). The expression of Mttp and secretion-associated, ras-related GTPase 1 gene homolog B (Sar1b, CM secretion), carnitine palmitoyltransferase IA (Cpt1a) and acyl-coenzyme A oxidase 1 (Acox1, beta-oxidation), and fatty acid desaturase 2 (Fads2, bioconversion of ALA into long-chain n-3 PUFAs) were, respectively, 49%, 29%, 74%, 48%, and 55% higher in the 30%-RL group vs. the control group (P < 0.05). CONCLUSIONS: In rats, RL enhanced lymphatic lipid output, as well as the rate of appearance of ALA, which may promote its subsequent bioavailability and metabolic fate.
Assuntos
Brassica napus/química , Lecitinas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Linfa/química , Linfa/metabolismo , Ácido alfa-Linolênico/metabolismo , Animais , Disponibilidade Biológica , Lecitinas/química , Ratos , Ácido alfa-Linolênico/químicaRESUMO
This study addressed the hypothesis that inhibiting the soluble epoxide hydrolase (sEH)-mediated degradation of epoxy-fatty acids, notably epoxyeicosatrienoic acids, has an additional impact against cardiovascular damage in insulin resistance, beyond its previously demonstrated beneficial effect on glucose homeostasis. The cardiovascular and metabolic effects of the sEH inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB; 10 mg/l in drinking water) were compared with those of the sulfonylurea glibenclamide (80 mg/l), both administered for 8 wk in FVB mice subjected to a high-fat diet (HFD; 60% fat) for 16 wk. Mice on control chow diet (10% fat) and nontreated HFD mice served as controls. Glibenclamide and t-AUCB similarly prevented the increased fasting glycemia in HFD mice, but only t-AUCB improved glucose tolerance and decreased gluconeogenesis, without modifying weight gain. Moreover, t-AUCB reduced adipose tissue inflammation, plasma free fatty acids, and LDL cholesterol and prevented hepatic steatosis. Furthermore, only the sEH inhibitor improved endothelium-dependent relaxations to acetylcholine, assessed by myography in isolated coronary arteries. This improvement was related to a restoration of epoxyeicosatrienoic acid and nitric oxide pathways, as shown by the increased inhibitory effects of the nitric oxide synthase and cytochrome P-450 epoxygenase inhibitors l-NA and MSPPOH on these relaxations. Moreover, t-AUCB decreased cardiac hypertrophy, fibrosis, and inflammation and improved diastolic function, as demonstrated by the increased E/A ratio (echocardiography) and decreased slope of the end-diastolic pressure-volume relation (invasive hemodynamics). These results demonstrate that sEH inhibition improves coronary endothelial function and prevents cardiac remodeling and diastolic dysfunction in obese insulin-resistant mice.
Assuntos
Benzoatos/farmacologia , Vasos Coronários/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Cardiopatias/prevenção & controle , Resistência à Insulina , Obesidade/tratamento farmacológico , Ureia/análogos & derivados , Vasodilatação/efeitos dos fármacos , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Vasos Coronários/enzimologia , Vasos Coronários/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Eicosanoides/metabolismo , Endotélio Vascular/enzimologia , Endotélio Vascular/fisiopatologia , Epóxido Hidrolases/metabolismo , Glibureto/farmacologia , Cardiopatias/enzimologia , Cardiopatias/etiologia , Cardiopatias/fisiopatologia , Hipoglicemiantes/farmacologia , Mediadores da Inflamação/metabolismo , Lipídeos/sangue , Masculino , Camundongos , Óxido Nítrico/metabolismo , Obesidade/sangue , Obesidade/complicações , Obesidade/enzimologia , Obesidade/fisiopatologia , Fatores de Tempo , Ureia/farmacologia , Vasodilatadores/farmacologia , Função Ventricular Esquerda/efeitos dos fármacos , Remodelação Ventricular/efeitos dos fármacosRESUMO
BACKGROUND: Polar lipid (PL) emulsifiers such as milk PLs (MPLs) may affect digestion and subsequent lipid metabolism, but focused studies on postprandial lipemia are lacking. OBJECTIVE: We evaluated the impact of MPLs on postprandial lipemia in mice and on lipid digestion in vitro. METHODS: Female Swiss mice were gavaged with 150 µL of an oil-in-water emulsion stabilized with 5.7 mg of either MPLs or soybean PLs (SPLs) and killed after 1, 2, or 4 h. Plasma lipids were quantified and in the small intestine, gene expression was analyzed by reverse transcriptase-quantitative polymerase chain reaction. Emulsions were lipolyzed in vitro using a static human digestion model; triglyceride (TG) disappearance was followed by thin-layer chromatography. RESULTS: In mice, after 1 h, plasma TGs tended to be higher in the MPL group than in the SPL group (141 µg/mL vs. 90 µg/mL; P = 0.07) and nonesterified fatty acids (NEFAs) were significantly higher (64 µg/mL vs. 44 µg/mL; P < 0.05). The opposite was observed after 4 h with lower TGs (21 µg/mL vs. 35 µg/mL; P < 0.01) and NEFAs (20 µg/mL vs. 32 µg/mL; P < 0.01) in the MPL group compared with the SPL group. This was associated at 4 h with a lower gene expression of apolipoprotein B (Apob) and Secretion Associated, Ras related GTPase 1 gene homolog B (Sar1b), in the duodenum of MPL mice compared with SPL mice (P < 0.05). In vitro, during the intestinal phase, TGs were hydrolyzed more in the MPL emulsion than in the SPL emulsion (decremental AUCs were 1750%/min vs. 180%/min; P < 0.01). MPLs enhance lipid intestinal hydrolysis and promote more rapid intestinal lipid absorption and sharper kinetics of lipemia. CONCLUSIONS: Postprandial lipemia in mice can be modulated by emulsifying with MPLs compared with SPLs, partly through differences in chylomicron assembly, and TG hydrolysis rate as observed in vitro. MPLs may thereby contribute to the long-term regulation of lipid metabolism.
Assuntos
Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos/farmacologia , Lipólise/efeitos dos fármacos , Leite/química , Animais , Emulsificantes , Feminino , Regulação da Expressão Gênica , Intestino Delgado/metabolismo , Lecitinas , Lipídeos/química , Camundongos , Período Pós-PrandialRESUMO
AIMS: The timecourse of left atrial Pitx2 down-regulation in the setting of atrial tachyarrhythmias remains unknown. Accordingly, we aimed to assess the age dependency of left atrial Pitx2 expression in an experimental model of spontaneous atrial tachyarrhythmias in rats. METHODS AND RESULTS: Atrial sampling was performed in three groups (n = 4 each) of young (14-week-old), adult (24-week-old), and ageing (48-week-old) spontaneously hypertensive rats (SHRs), in which we previously demonstrated the age dependency of spontaneous atrial tachyarrhythmias, and three groups (n = 4 each) of age-matched normotensive Wistar-Kyoto (WKY) rats. mRNA expression of Pitx2 was studied using real-time polymerase chain reaction. Ageing SHRs presented significantly lower left atrial Pitx2 expressions compared with age-matched WKY rats (P = 0.02), while no significant difference was observed between young or adult SHRs and age-matched WKY rats (both P > 0.05). Among SHRs, Pitx2 expressions showed a progressive, age-dependent decrease (34.9 ± 6.7 in young SHRs, 17.1 ± 3.6 in adult SHRs, and 10.7 ± 1.7 in ageing SHRs, P = 0.04) and were significantly negatively correlated with both age (Spearman r = -0.86, P < 0.01) and heart weight (Spearman r = -0.76, P < 0.01). CONCLUSION: The present study suggests the presence of age-dependent left atrial Pitx2 down-regulation in SHRs. The strong negative correlation between left atrial Pitx2 expression and heart weight among SHRs may indicate a link between long-standing arterial hypertension and Pitx2-related atrial arrhythmogenicity.
Assuntos
Envelhecimento/metabolismo , Fibrilação Atrial/etiologia , Fibrilação Atrial/metabolismo , Proteínas de Homeodomínio/metabolismo , Hipertensão/complicações , Hipertensão/metabolismo , Fatores de Transcrição/metabolismo , Animais , Doença Crônica , Regulação para Baixo , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Proteína Homeobox PITX2RESUMO
Dairy products derived from the milk of cows fed in pastures are characterised by higher amounts of conjugated linoleic acid and α-linolenic acid (ALA), and several studies have shown their ability to reduce cardiovascular risk. However, their specific metabolic effects compared with standard dairy in a high-fat diet (HFD) context remain largely unknown; this is what we determined in the present study with a focus on the metabolic and intestinal parameters. The experimental animals were fed for 12 weeks a HFD containing 20 % fat in the form of a pasture dairy cream (PDC) or a standard dairy cream (SDC). Samples of plasma, liver, white adipose tissue, duodenum, jejunum and colon were analysed. The PDC mice, despite a higher food intake, exhibited lower fat mass, plasma and hepatic TAG concentrations, and inflammation in the adipose tissue than the SDC mice. Furthermore, they exhibited a higher expression of hepatic PPARα mRNA and adipose tissue uncoupling protein 2 mRNA, suggesting an enhanced oxidative activity of the tissues. These results might be explained, in part, by the higher amounts of ALA in the PDC diet and in the liver and adipose tissue of the PDC mice. Moreover, the PDC diet was found to increase the proportions of two strategic cell populations involved in the protective function of the intestinal epithelium, namely Paneth and goblet cells in the small intestine and colon, compared with the SDC diet. In conclusion, a PDC HFD leads to improved metabolic outcomes and to a stronger gut barrier compared with a SDC HFD. This may be due, at least in part, to the protective mechanisms induced by specific lipids.
Assuntos
Bovinos/fisiologia , Dieta/veterinária , Gorduras na Dieta/uso terapêutico , Alimento Funcional , Leite , Obesidade/fisiopatologia , Paniculite/prevenção & controle , Tecido Adiposo Branco/imunologia , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Criação de Animais Domésticos , Animais , Laticínios/efeitos adversos , Laticínios/análise , Dieta Hiperlipídica/efeitos adversos , Gorduras na Dieta/efeitos adversos , Gorduras na Dieta/análise , Gorduras na Dieta/metabolismo , Feminino , Alimento Funcional/análise , Hipertrigliceridemia/etiologia , Hipertrigliceridemia/prevenção & controle , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Mucosa Intestinal/fisiopatologia , Lactação , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Leite/efeitos adversos , Leite/química , Leite/metabolismo , Obesidade/imunologia , Obesidade/metabolismo , Obesidade/patologia , Paniculite/etiologia , Componentes Aéreos da Planta/química , Componentes Aéreos da Planta/crescimento & desenvolvimento , Poaceae/química , Poaceae/crescimento & desenvolvimento , Distribuição AleatóriaRESUMO
SCOPE: Lipopolysaccharides and their transporters, LBP and sCD14, are involved in systemic inflammation following a high-fat diet. Natural emulsifiers such as soy lecithin, rich in soybean polar lipids (SPL), are often used by the food industry but little is known about effects of associating SPL with different oils. METHODS AND RESULTS: Thus, this study investigates the effects of 4 weeks feeding of palm (P) or rapeseed (R) oil-enriched diets with or without SPL in mice, on white adipose tissue (WAT) inflammation, on ileum permeability, and on microbiota composition. When SPL are associated with rapeseed oil, a greater gene expression of leptin and inflammation in WAT is observed compared to P-SPL. In ileum, R-SPL group results in a lower expression of TLR4, IAP that detoxify bacterial LPS and tight junction proteins than R group. In turn, the gene expression of Reg3ß and Reg3γ, which have antimicrobial activity, is higher in ileum of R-SPL group than in R group. SPL in rapeseed oil increases specific bacterial species belonging to Lachnospiraceae, Alistipes, and Bacteroidales. CONCLUSION: The incorporation of SPL in a diet with rapeseed oil exerts differential effect on WAT and ileum, with respectively an inflammation of WAT and an antimicrobial activity in ileum, associated with specific microbiota changes.
Assuntos
Anti-Infecciosos , Dieta Hiperlipídica , Camundongos , Animais , Dieta Hiperlipídica/efeitos adversos , Lecitinas , Óleo de Brassica napus/farmacologia , Tecido Adiposo/metabolismo , Tecido Adiposo Branco , Inflamação/metabolismo , Glycine max , Íleo/metabolismo , Anti-Infecciosos/farmacologiaRESUMO
Supplementation with probiotics has emerged as a promising therapeutic tool to manage metabolic diseases. We investigated the effects of a mix of Bifidobacterium animalis subsp. lactis LA804 and Lactobacillus gasseri LA806 on high-fat (HF) diet -induced metabolic disease in mice. Supplementation with the probiotic mix in HF diet-fed mice (HF-Pr2) reduced weight and fat mass gains, decreased hepatic lipid accumulation, and lowered plasma triglyceride peak during an oral lipid tolerance test. At the molecular level, the probiotic mix protected against HF-induced rise in mRNA levels of genes related to lipid uptake, metabolism, and storage in the liver and white adipose tissues, and strongly decreased mRNA levels of genes related to inflammation in the white adipose tissue and to oxidative stress in the liver. Regarding intestinal homeostasis, the probiotic mix did not prevent HF-induced gut permeability but slightly modified microbiota composition without correcting the dysbiosis induced by the HF diet. Probiotic supplementation also modified the cecal bile acid (BA) profile, leading to an increase in the Farnesoid-X-Receptor (FXR) antagonist/agonist ratio between BA species. In agreement, HF-Pr2 mice exhibited a strong inhibition of FXR signaling pathway in the ileum, which was associated with lipid metabolism protection. This is consistent with recent reports proposing that inhibition of intestinal FXR activity could be a potent mechanism to overcome metabolic disorders. Altogether, our results demonstrate that the probiotic mix evaluated, when administered preventively to HF diet-fed mice could limit obesity and associated lipid metabolism disorders, likely through the inhibition of FXR signaling in the intestinal tract.
Assuntos
Microbioma Gastrointestinal , Probióticos , Camundongos , Animais , Dieta Hiperlipídica/efeitos adversos , Metabolismo dos Lipídeos , Aumento de Peso , Probióticos/farmacologia , Probióticos/uso terapêutico , Fígado/metabolismo , Triglicerídeos , RNA Mensageiro/metabolismo , RNA Mensageiro/farmacologia , Camundongos Endogâmicos C57BL , Ácidos e Sais Biliares/metabolismoRESUMO
Dietary intake of long-chain n-3 PUFA is now widely advised for public health and in medical practice. However, PUFA are highly prone to oxidation, producing potentially deleterious 4-hydroxy-2-alkenals. Even so, the impact of consuming oxidized n-3 PUFA on metabolic oxidative stress and inflammation is poorly described. We therefore studied such effects and hypothesized the involvement of the intestinal absorption of 4-hydroxy-2-hexenal (4-HHE), an oxidized n-3 PUFA end-product. In vivo, four groups of mice were fed for 8 weeks high-fat diets containing moderately oxidized or unoxidized n-3 PUFA. Other mice were orally administered 4-HHE and euthanized postprandially versus baseline mice. In vitro, human intestinal Caco-2/TC7 cells were incubated with 4-hydroxy-2-alkenals. Oxidized diets increased 4-HHE plasma levels in mice (up to 5-fold, P < 0.01) compared with unoxidized diets. Oxidized diets enhanced plasma inflammatory markers and activation of nuclear factor kappaB (NF-κB) in the small intestine along with decreasing Paneth cell number (up to -19% in the duodenum). Both in vivo and in vitro, intestinal absorption of 4-HHE was associated with formation of 4-HHE-protein adducts and increased expression of glutathione peroxidase 2 (GPx2) and glucose-regulated protein 78 (GRP78). Consumption of oxidized n-3 PUFA results in 4-HHE accumulation in blood after its intestinal absorption and triggers oxidative stress and inflammation in the upper intestine.
Assuntos
Aldeídos/farmacocinética , Dieta Hiperlipídica , Ácidos Graxos Ômega-3/metabolismo , Inflamação/metabolismo , Mucosa Intestinal/metabolismo , Estresse Oxidativo , Aldeídos/administração & dosagem , Animais , Biomarcadores/metabolismo , Células CACO-2 , Chaperona BiP do Retículo Endoplasmático , Glutationa Peroxidase/metabolismo , Proteínas de Choque Térmico/metabolismo , Humanos , Absorção Intestinal/fisiologia , Peroxidação de Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , OxirreduçãoRESUMO
Low-grade inflammation observed in obesity is a risk factor for cardiovascular disease. Recent studies revealed that this would be linked to gut-derived endotoxemia during fat digestion in high-fat diets, but nothing is known about the effect of lipid composition. The study was designed to test the impact of oil composition of high-fat diets on endotoxin metabolism and inflammation in mice. C57/Bl6 mice were fed for 8 wk with chow or isocaloric isolipidic diets enriched with oils differing in fatty acid composition: milk fat, palm oil, rapeseed oil, or sunflower oil. In vitro, adipocytes (3T3-L1) were stimulated or not with lipopolysaccharide (LPS; endotoxin) and incubated with different fatty acids. In mice, the palm group presented the highest level of IL-6 in plasma (P < 0.01) together with the highest expression in adipose tissue of IL-1ß and of LPS-sensing TLR4 and CD14 (P < 0.05). The higher inflammation in the palm group was correlated with a greater ratio of LPS-binding protein (LBP)/sCD14 in plasma (P < 0.05). The rapeseed group resulted in higher sCD14 than the palm group, which was associated with lower inflammation in both plasma and adipose tissue despite higher plasma endotoxemia. Taken together, our results reveal that the palm oil-based diet resulted in the most active transport of LPS toward tissues via high LBP and low sCD14 and the greatest inflammatory outcomes. In contrast, a rapeseed oil-based diet seemed to result in an endotoxin metabolism driven toward less inflammatory pathways. This shows that dietary fat composition can contribute to modulate the onset of low-grade inflammation through the quality of endotoxin receptors.
Assuntos
Tecido Adiposo Branco/imunologia , Citocinas/metabolismo , Dieta Hiperlipídica/efeitos adversos , Doenças Metabólicas/etiologia , Doenças Metabólicas/imunologia , Receptores Imunológicos/metabolismo , Células 3T3-L1 , Proteínas de Fase Aguda , Tecido Adiposo Branco/metabolismo , Animais , Biomarcadores/sangue , Biomarcadores/metabolismo , Proteínas de Transporte/sangue , Citocinas/sangue , Ácidos Graxos Monoinsaturados , Ácidos Graxos não Esterificados/efeitos adversos , Ácidos Graxos não Esterificados/sangue , Bactérias Gram-Negativas/imunologia , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/imunologia , Bactérias Gram-Positivas/isolamento & purificação , Intestinos/imunologia , Intestinos/microbiologia , Intestinos/patologia , Receptores de Lipopolissacarídeos/sangue , Receptores de Lipopolissacarídeos/metabolismo , Masculino , Glicoproteínas de Membrana/sangue , Doenças Metabólicas/metabolismo , Doenças Metabólicas/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Óleo de Palmeira , Óleos de Plantas/efeitos adversos , Distribuição Aleatória , Óleo de Brassica napus , Óleo de Girassol , Receptor 4 Toll-Like/metabolismoRESUMO
Interactions between mitochondria and the endoplasmic reticulum, known as MAMs, are altered in the liver in obesity, which contributes to disruption of the insulin signaling pathway. In addition, the plasma level of glycine is decreased in obesity, and the decrease is strongly correlated with the severity of insulin resistance. Certain nutrients have been shown to regulate MAMs; therefore, we tested whether glycine supplementation could reduce insulin resistance in the liver by promoting MAM integrity. Glycine (5 mM) supported MAM integrity and insulin response in primary rat hepatocytes cultured under control and lipotoxic (palmitate 500 µM) conditions for 18 h. In contrast, in C57 BL/6 JOlaHsd mice (male, 6 weeks old) fed a high-fat, high-sucrose diet (HFHS) for 16 weeks, glycine supplementation (300 mg/kg) in drinking water during the last 6 weeks (HFHS-Gly) did not reverse the deleterious impact of HFHS-feeding on liver MAM integrity. In addition, glycine supplementation worsened fasting glycemia and glycemic response to intraperitoneal pyruvate injection compared to HFHS. The adverse impact of glycine supplementation on hepatic gluconeogenesis was further supported by the higher oxaloacetate/acetyl-CoA ratio in the liver in HFHS-Gly compared to HFHS. Although glycine improves MAM integrity and insulin signaling in the hepatocyte in vitro, no beneficial effect was found on the overall metabolic profile of HFHS-Gly-fed mice.
Assuntos
Intolerância à Glucose , Resistência à Insulina , Masculino , Ratos , Camundongos , Animais , Intolerância à Glucose/metabolismo , Resistência à Insulina/fisiologia , Gluconeogênese , Glicina/farmacologia , Fígado/metabolismo , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Insulina , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Camundongos Endogâmicos C57BLRESUMO
Environmental pollutants suspected of disrupting the endocrine system are considered etiologic factors in the epidemic of metabolic disorders. As regulation of energy metabolism relies on the integrated action of a large number of hormones, we hypothesized that certain chemicals could trigger changes in glucocorticoid signaling. To this end, we exposed C57Bl6/J female and male mice between 5 and 20 weeks of age to a mixture of 2,3,7,8- tetrachlorodibenzo-p-dioxin (20 pg/kg body weight/day [bw/d]), polychlorobiphenyl 153 (200 ng/kg bw/d), di-[2-ethylhexyl]-phthalate (500 µg/kg bw/d) and bisphenol A (40 µg/kg bw/d). In female mice fed a standard diet (ST), we observed a decrease in plasma levels of leptin as well as a reduced expression of corticoid receptors Nr3c1 and Nr3c2, of leptin and of various canonical genes related to the circadian clock machinery in visceral (VAT) but not subcutaneous (SAT) adipose tissue. However, Nr3c1 and Nr3c2 mRNA levels did not change in high-fat-fed females exposed to pollutants. In ST-fed males, pollutants caused the same decrease of Nr3c1 mRNA levels in VAT observed in ST-fed females but levels of Nr3c2 and other clock-related genes found to be down-regulated in female VAT were enhanced in male SAT and not affected in male VAT. The expression of corticoid receptors was not affected in the livers of both sexes in response to pollutants. In summary, exposure to a mixture of pollutants at doses lower than the no-observed adverse effect levels (NoAELs) resulted in sex-dependent glucocorticoid signaling disturbances and clock-related gene expression modifications in the adipose tissue of ST-fed mice.
Assuntos
Poluentes Ambientais/toxicidade , Glucocorticoides/metabolismo , Tecido Adiposo/metabolismo , Animais , Compostos Benzidrílicos , Peso Corporal , Poluentes Ambientais/metabolismo , Feminino , Expressão Gênica , Leptina/sangue , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenóis , Dibenzodioxinas Policloradas/metabolismo , RNA Mensageiro/metabolismo , Sensibilidade e EspecificidadeRESUMO
SCOPE: Synthetic emulsifiers have recently been shown to promote metabolic syndrome and considerably alter gut microbiota. Yet, data are lacking regarding the effects of natural emulsifiers, such as plant lecithins rich in essential α-linolenic acid (ALA), on gut and metabolic health. METHODS AND RESULTS: For 5 days, male Swiss mice are fed diets containing similar amounts of ALA and 0, 1, 3, or 10% rapeseed lecithin (RL) or 10% soy lecithin (SL). Following an overnight fast, they are force-fed the same oil mixture and euthanized after 90 minutes. The consumption of lecithin significantly increased fecal levels of the Clostridium leptum group (p = 0.0004), regardless of origin or dose, without altering hepatic or intestinal expression of genes of lipid metabolism. 10%-RL increased ALA abundance in plasma triacylglycerols at 90 minutes, reduced cecal bile acid hydrophobicity, and increased their sulfatation, as demonstrated by the increased hepatic RNA expression of Sult2a1 (p = 0.037) and cecal cholic acid-7 sulfate (CA-7S) concentration (p = 0.05) versus 0%-lecithin. CONCLUSION: After only 5 days, nutritional doses of RL and SL modified gut bacteria in mice, by specifically increasing C. leptum group. RL also increased postprandial ALA abundance and induced beneficial modifications of the bile acid profile. ALA-rich lecithins, especially RL, may then appear as promising natural emulsifiers.
Assuntos
Ácidos e Sais Biliares/análise , Brassica napus , Microbioma Gastrointestinal/efeitos dos fármacos , Glycine max , Lecitinas/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Animais , Ácidos e Sais Biliares/metabolismo , Lipídeos/sangue , Masculino , Camundongos , Período Pós-Prandial/fisiologia , Ácido alfa-Linolênico/administração & dosagemRESUMO
In the liver, contact sites between the endoplasmic reticulum (ER) and mitochondria (named MAMs) may be crucial hubs for the regulation of lipid metabolism, thus contributing to the exacerbation or prevention of fatty liver. We hypothesized that tether proteins located at MAMs could play a key role in preventing triglyceride accumulation in hepatocytes and nonalcoholic fatty liver disease (NAFLD) occurrence. To test this, we explored the role of two key partners in building MAM integrity and functionality, the glucose-regulated protein 75 (Grp75) and mitofusin 2 (Mfn2), which liver contents are altered in obesity and NAFLD. Grp75 or Mfn2 expression was either silenced using siRNA or overexpressed with adenoviruses in Huh7 cells. Silencing of Grp75 and Mfn2 resulted in decreased ER-mitochondria interactions, mitochondrial network fusion state and mitochondrial oxidative capacity, while overexpression of the two proteins induced mirror impacts on these parameters. Furthermore, Grp75 or Mfn2 silencing decreased cellular cholesterol content and enhanced triglyceride secretion in ApoB100 lipoproteins, while their overexpression led to reverse effects. Cellular phosphatidylcholine/phosphatidylethanolamine ratio was decreased only upon overexpression of the proteins, potentially contributing to altered ApoB100 assembly and secretion. Despite the opposite differences, both silencing and overexpression of Grp75 or Mfn2 induced triglyceride storage, although a fatty acid challenge was required to express the alteration upon protein silencing. Among the mechanisms potentially involved in this phenotype, ER stress was closely associated with altered triglyceride metabolism after Grp75 or Mfn2 overexpression, while blunted mitochondrial FA oxidation capacity may be the main defect causing triglyceride accumulation upon Grp75 or Mfn2 silencing. Further studies are required to decipher the link between modulation of Grp75 or Mfn2 expression, change in MAM integrity and alteration of cholesterol content of the cell. In conclusion, Grp75 or Mfn2 silencing and overexpression in Huh7 cells contribute to altering MAM integrity and cholesterol storage in opposite directions, but all promote triglyceride accumulation through distinct cellular pathways. This study also highlights that besides Mfn2, Grp75 could play a central role in hepatic lipid and cholesterol metabolism in obesity and NAFLD.
Assuntos
Apolipoproteína B-100/genética , Colesterol/metabolismo , GTP Fosfo-Hidrolases/genética , Proteínas de Choque Térmico HSP70/genética , Proteínas Mitocondriais/genética , Hepatopatia Gordurosa não Alcoólica/genética , Linhagem Celular , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , GTP Fosfo-Hidrolases/antagonistas & inibidores , Mutação com Ganho de Função/genética , Regulação da Expressão Gênica/genética , Inativação Gênica , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Mutação com Perda de Função/genética , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/antagonistas & inibidores , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Triglicerídeos/metabolismoRESUMO
Muscle atrophy arises from a multiplicity of physio-pathological situations and has very detrimental consequences for the whole body. Although knowledge of muscle atrophy mechanisms keeps growing, there is still no proven treatment to date. This study aimed at identifying new drivers for muscle atrophy resistance. We selected an innovative approach that compares muscle transcriptome between an original model of natural resistance to muscle atrophy, the hibernating brown bear, and a classical model of induced atrophy, the unloaded mouse. Using RNA sequencing, we identified 4415 differentially expressed genes, including 1746 up- and 2369 down-regulated genes, in bear muscles between the active versus hibernating period. We focused on the Transforming Growth Factor (TGF)-ß and the Bone Morphogenetic Protein (BMP) pathways, respectively, involved in muscle mass loss and maintenance. TGF-ß- and BMP-related genes were overall down- and up-regulated in the non-atrophied muscles of the hibernating bear, respectively, and the opposite occurred for the atrophied muscles of the unloaded mouse. This was further substantiated at the protein level. Our data suggest TGF-ß/BMP balance is crucial for muscle mass maintenance during long-term physical inactivity in the hibernating bear. Thus, concurrent activation of the BMP pathway may potentiate TGF-ß inhibiting therapies already targeted to prevent muscle atrophy.
Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Hibernação , Atrofia Muscular/metabolismo , Músculo Quadríceps/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Ursidae/metabolismo , Animais , Proteínas Morfogenéticas Ósseas/genética , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Elevação dos Membros Posteriores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atrofia Muscular/genética , Atrofia Muscular/patologia , Músculo Quadríceps/patologia , RNA-Seq , Transdução de Sinais , Fatores de Tempo , Transcriptoma , Fator de Crescimento Transformador beta/genética , Ursidae/genéticaRESUMO
Maternal protein restriction and physical activity can affect the interaction mother-placenta-fetus. This study quantified the gene expression of brain-derived neurotrophic factor (BDNF), neurothrophin 4, tyrosine kinase receptor B (TrkB/NTRK2), insulin-like growth factor (IGF-1), and insulin-like growth factor receptor (IGF-1r) in the different areas of mother's brain (hypothalamus, hippocampus, and cortex), placenta, and fetus' brain of rats. Female Wistar rats (n = 20) were housed in cages containing a running wheel for 4 weeks before gestation. According to the distance spontaneously traveled daily, rats were classified as inactive or active. During gestation, on continued access to the running wheel, active and inactive groups were randomized to receive normoprotein diet (18% protein) or a low-protein (LP) diet (8% protein). At day 20 of gestation, gene expression of neurotrophic factors was analyzed by quantitative polymerase chain reaction in different brain areas and the placenta. Dams submitted to a LP diet during gestation showed upregulation of IGF-1r and BDNF messenger RNA in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, and BDNF, NTRK2, IGF-1 and IGF-1r in the cortex. In the placenta, there was a downregulation of IGF-1. In the brain of pups from mothers on LP diet, IGF-1r and NTRK2 were downregulated. Voluntary physical activity attenuated the effects of LP diet on IGF-1r in the hypothalamus, IGF-1r and NTRK2 in the hippocampus, IGF-1 in the placenta, and NTRK2 in the fetus' brain. In conclusion, both maternal protein restriction and spontaneous physical activity influence the gene expression of BDNF, NTRK2, IGF-1, and IGF-1r, with spontaneous physical activity being able to normalize in part the defects caused by protein restriction during pregnancy.
Assuntos
Encéfalo/metabolismo , Dieta com Restrição de Proteínas , Fenômenos Fisiológicos da Nutrição Materna , Fatores de Crescimento Neural/metabolismo , Placenta/metabolismo , Animais , Feminino , Masculino , Plasticidade Neuronal , Condicionamento Físico Animal , Placentação , Gravidez , Ratos WistarRESUMO
BACKGROUNDHigh circulating levels of ceramides (Cer) and sphingomyelins (SM) are associated with cardiometabolic diseases. The consumption of whole fat dairy products, naturally containing such polar lipids (PL), is associated with health benefits, but the impact on sphingolipidome remains unknown.METHODSIn a 4-week randomized controlled trial, 58 postmenopausal women daily consumed milk PL-enriched cream cheese (0, 3, or 5 g of milk PL). Postprandial metabolic explorations were performed before and after supplementation. Analyses included SM and Cer species in serum, chylomicrons, and feces. The ileal contents of 4 ileostomy patients were also explored after acute milk PL intake.RESULTSMilk PL decreased serum atherogenic C24:1 Cer, C16:1 SM, and C18:1 SM species (Pgroup < 0.05). Changes in serum C16+18 SM species were positively correlated with the reduction of cholesterol (r = 0.706), LDL-C (r = 0.666), and ApoB (r = 0.705) (P < 0.001). Milk PL decreased chylomicron content in total SM and C24:1 Cer (Pgroup < 0.001), parallel to a marked increase in total Cer in feces (Pgroup < 0.001). Milk PL modulated some specific SM and Cer species in both ileal efflux and feces, suggesting differential absorption and metabolization processes in the gut.CONCLUSIONMilk PL supplementation decreased atherogenic SM and Cer species associated with the improvement of cardiovascular risk markers. Our findings bring insights on sphingolipid metabolism in the gut, especially Cer, as signaling molecules potentially participating in the beneficial effects of milk PL.TRIAL REGISTRATIONClinicalTrials.gov, NCT02099032, NCT02146339.FUNDINGANR-11-ALID-007-01; PHRCI-2014: VALOBAB, no. 14-007; CNIEL; GLN 2018-11-07; HCL (sponsor).
Assuntos
Ceramidas , Metabolismo dos Lipídeos/fisiologia , Leite , Pós-Menopausa/metabolismo , Esfingomielinas , Animais , Ceramidas/análise , Ceramidas/sangue , Ceramidas/metabolismo , Queijo , Dieta , Fezes/química , Feminino , Glicolipídeos/metabolismo , Glicoproteínas/metabolismo , Humanos , Gotículas Lipídicas/metabolismo , Sobrepeso , Esfingomielinas/análise , Esfingomielinas/sangue , Esfingomielinas/metabolismoRESUMO
Atherosclerosis is a chronic systemic inflammatory disease, inducing cardiovascular and cerebrovascular acute events. A role of neuroinflammation is suspected, but not yet investigated in the gyrencephalic brain and the related activity at blood-brain interfaces is unknown. A non-human primate model of advanced atherosclerosis was first established using longitudinal blood samples, multimodal imaging and gene analysis in aged animals. Non-human primate carotid lesions were compared with human carotid endarterectomy samples. During the whole-body imaging session, imaging of neuroinflammation and choroid plexus function was performed. Advanced plaques were present in multiple sites, premature deaths occurred and downstream lesions (myocardial fibrosis, lacunar stroke) were present in this model. Vascular lesions were similar to in humans: high plaque activity on PET and MRI imaging and systemic inflammation (high plasma C-reactive protein levels: 42 ± 14 µg/ml). We also found the same gene association (metabolic, inflammatory and anti-inflammatory markers) as in patients with similar histological features. Metabolic imaging localized abnormal brain glucose metabolism in the frontal cortex. It corresponded to cortical neuro-inflammation (PET imaging) that correlated with C-reactive protein level. Multimodal imaging also revealed pronounced choroid plexus function impairment in aging atherosclerotic non-human primates. In conclusion, multimodal whole-body inflammation exploration at the vascular level and blood-brain interfaces identified high-risk aging atherosclerosis. These results open the way for systemic and central inflammation targeting in atherosclerosis in the new era of immunotherapy.
RESUMO
OBJECTIVE: Human conditions with upregulated receptor uptake of low-density lipoproteins (LDL) are associated with diabetes risk, the reasons for which remain unexplored. LDL induce metabolic dysfunction in murine adipocytes. Thus, it was hypothesized that white adipose tissue (WAT) surface expression of LDL receptor (LDLR) and/or CD36 is associated with WAT and systemic metabolic dysfunction. Whether WAT LDLR and CD36 expression is predicted by plasma lipoprotein-related parameters was also explored. METHODS: This was a cross-sectional analysis of 31 nondiabetic adults (BMI > 25 kg/m2 ) assessed for WAT surface expression of LDLR and CD36 (immunohistochemistry), WAT function, WAT and systemic inflammation, postprandial fat metabolism, and insulin resistance (IR; hyperinsulinemic-euglycemic clamp). RESULTS: Fasting WAT surface expression of LDLR and CD36 was negatively associated with WAT function (3 H-triglyceride storage, r = -0.45 and -0.66, respectively) and positively associated with plasma IL-1 receptor antagonist (r = 0.64 and 0.43, respectively). Their expression was suppressed 4 hours postprandially, and reduced LDLR was further associated with IR (M/Iclamp , r = 0.61 women, r = 0.80 men). Plasma apolipoprotein B (apoB)-to-PCSK9 ratio predicted WAT surface expression of LDLR and CD36, WAT dysfunction, WAT NLRP3 inflammasome priming and disrupted cholesterol-sensing genes, and systemic IR independent of sex and body composition. CONCLUSIONS: Higher fasting and lower postprandial WAT surface expression of LDLR and CD36 is associated with WAT dysfunction, systemic inflammation, and IR in adults with overweight/obesity, anomalies that are predicted by higher plasma apoB-to-PCSK9 ratio.
Assuntos
Tecido Adiposo Branco/metabolismo , Antígenos CD36/metabolismo , Diabetes Mellitus Tipo 2/genética , Obesidade/metabolismo , Receptores de LDL/metabolismo , Idoso , Estudos Transversais , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Fatores de RiscoRESUMO
Maternal physical activity induces brain functional changes and neuroplasticity, leading to an improvement of cognitive functions, such as learning and memory in the offspring. This study investigated the effects of voluntary maternal physical activity on the gene expression of the neurotrophic factors (NTFs): BDNF, NTF4, NTRK2, IGF-1 and IGF-1r in the different areas of mother's brain, placenta and foetus brain of rats. Female Wistar rats (n = 15) were individually housed in voluntary physical activity cages, containing a running wheel, for 4 weeks (period of adaptation) before gestation. Rats were classified as inactive (I, n = 6); active (A, n = 4) and very active (VA, n = 5) according to daily distance spontaneously travelled. During gestation, the dams continued to have access to the running wheel. At the 20th day of gestation, gene expression of NTFs was analysed in different areas of mother's brain (cerebellum, hypothalamus, hippocampus and cortex), placenta and the offspring's brain. NTFs gene expression was evaluated using quantitative PCR. Very active mothers showed upregulation of IGF-1 mRNA in the cerebellum (36.8%) and NTF4 mRNA expression in the placenta (24.3%). In the cortex, there was a tendency of up-regulation of NTRK2 mRNA (p = 0.06) in the A and VA groups when compared to I group. There were no noticeable changes in the gene expression of NTFs in the offspring's brain. Our findings suggest the existence of a developmental plasticity induced by maternal physical activity in specific areas of the brain and placenta representing the first investment for offspring during development.