RESUMO
The study of the mechanisms that trigger inflammation in adipose tissue is key to understanding and preventing the cardiometabolic consequences of obesity. We have proposed a model where activation of the G protein-coupled calcium sensing receptor (CaSR) leads to inflammation and dysfunction in adipose cells. Upon activation, CaSR can mediate the expression and secretion of proinflammatory factors in human preadipocytes, adipocytes, and adipose tissue explants. One possible pathway involved in CaSR-induced inflammation is the activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome, that promotes maturation and secretion of interleukin (IL)-1ß. The present work aimed to study whether CaSR mediates the activation of NLRP3 inflammasome in the human adipose cell model LS14. We assessed NLRP3 inflammasome priming and assembly after cinacalcet-induced CaSR activation and evaluated if this activation is mediated by downstream ERK1/2 signaling in LS14 preadipocytes. Exposure to 2 µM cinacalcet elevated mRNA expression of NLRP3, CASP-1, and IL-1ß, as well as an increase in pro-IL-1ß protein. In addition, CaSR activation triggered NLRP3 inflammasome assembly, as evidenced by a 25% increase in caspase-1 activity and 63% IL-1ß secretion. CaSR silencing (siRNA) abolished the effect. Upstream ERK pathway inhibition decreased cinacalcet-dependent activation of NLRP3 inflammasome. We propose CaSR-dependent NLRP3 inflammasome activation in preadipocytes through ERK signaling as a novel mechanism for the development of adipose dysfunction, that may favor the cardiovascular and metabolic consequences of obesity. To the best of our knowledge, this is the first report linking the inflammatory effect of CaSR to NLRP3 inflammasome induction in adipose cells.
Assuntos
Adipócitos/metabolismo , Inflamassomos/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Receptores de Detecção de Cálcio/metabolismo , Tecido Adiposo/metabolismo , Caspase 1/metabolismo , Linhagem Celular Tumoral , Humanos , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Obesidade/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Background: Rosa mosqueta (RM) oil is characterized by high concentrations of antioxidants and α-linolenic acid (ALA; 18:3n-3). We have previously demonstrated in male C57BL/6J mice that RM decreases hepatic steatosis, a condition strongly associated with oxidative stress and inflammation.Objective: We studied the molecular mechanisms that underlie the role of RM in preventing high-fat diet (HFD)-induced oxidative stress and inflammation.Methods: Male C57BL/6J mice aged 28 d and weighing 12-14 g were divided into the following groups and fed for 12 wk: control diet (CD; 10% fat, 20% protein, and 70% carbohydrates); CD + RM (1.94 mg ALA â g body weight-1 â d-1 administered by oral gavage); HFD (60% fat, 20% protein, and 20% carbohydrates); and HFD + RM. General parameters (body weight, visceral fat, and histology); glucose metabolism [homeostasis model assessment and blood glucose area under the curve (AUC)]; oxidative stress [hepatic nuclear factor (erythroid-derived 2)-like-2 (NRF2) and heme oxygenase 1 (HO-1) concentrations]; and inflammation [hepatic peroxisome proliferator-activated receptor α (PPAR-α) and acyl-coenzyme A oxidase 1 (ACOX1) concentrations, blood tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) concentrations, and Tnfa and Il1b mRNA expression in liver and visceral adipose tissue] were evaluated.Results: In the HFD + RM mice, the final body weight (24.8 ± 1.1 g) was 19% lower than in the HFD mice (30.6 ± 2.8 g) (P < 0.05). Visceral fat was 34% lower in the HFD + RM mice than in the HFD mice (P < 0.05). The blood glucose AUC was 29% lower and Tnfa and Il1b expression levels were 47% and 59% lower, respectively, in the HFD + RM mice than in the HFD mice (P < 0.05). HFD + RM mice had 40% less hepatic steatosis (P < 0.05) and lower upregulation of PPAR-α (33%), ACOX1 (50%), NRF2 (39%), and HO-1 (68%) protein concentrations than did the HFD mice (P < 0.05).Conclusions: Our findings suggest that RM supplementation prevents the obese phenotype observed in HFD-fed mice by downregulating inflammatory cytokine expression and secretion and stimulating hepatic antioxidant and fatty acid oxidation markers.
Assuntos
Inflamação/tratamento farmacológico , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , PPAR alfa/metabolismo , Óleos de Plantas/farmacologia , Rosa/química , Animais , Glicemia , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/efeitos adversos , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Insulina/sangue , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/genética , PPAR alfa/genética , Óleos de Plantas/química , Regulação para CimaRESUMO
The calcium sensing receptor (CaSR) is expressed in human adipose cells, and its activation may associate with adipose tissue (AT) dysfunction. We evaluated whether CaSR stimulation influences adipocyte triglyceride (TG) and fatty acid binding protein 4 (aP2) content, and hepatocyte TGs and proinflammatory cytokine expression. The effect of the calcimimetic cinacalcet on TGs (fluorimetry), lipogenic genes (qPCR) and aP2 (immunoblot) was evaluated in LS14 adipocytes or AT. In the human HepG2 hepatic cell line, we assessed CaSR expression and cinacalcet effect on TGs and lipogenic and proinflammatory genes. CaSR activation decreased adipocyte TG content by 20% and the expression of GPD and LPL by 34% and 20%, respectively. Cinacalcet increased aP2 protein expression by 60%. CaSR expression was shown in HepG2 cells and human liver samples. Cinacalcet-treated HepG2 cells in the presence of oleic acid exhibited a19% increased TG content. No changes were observed in the expression of lipogenic genes in HepG2 cells, however there was a 50%-300% elevation in the expression of proinflammatory cytokines. CaSR activation in adipocytes may associate with decreased TG storage ability and increased aP2. Hepatic CaSR stimulation may elevate steatosis and proinflammatory factors. We propose that CaSR may contribute to obesity-associated hepatic metabolic consequences.
Assuntos
Adipócitos/metabolismo , Fígado/metabolismo , Receptores de Detecção de Cálcio/metabolismo , Adipogenia , Tecido Adiposo/metabolismo , Diferenciação Celular , Sobrevivência Celular , Cinacalcete/química , Citocinas/metabolismo , Proteínas de Ligação a Ácido Graxo/metabolismo , Células Hep G2 , Humanos , Inflamação , RNA/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Triglicerídeos/metabolismoRESUMO
Brain physiology and morphology are vulnerable to chronic stress, impacting cognitive performance and behavior. However, functional compounds found in food may alleviate these alterations. White quinoa (Chenopodium quinoa, Wild) seeds contain a high content of n-3 fatty acids, including alpha-linolenic acid. This study aimed to evaluate the potential neuroprotective role of a quinoa-based functional food (QFF) in rats. Prepubertal male Sprague-Dawley rats were fed with rat chow or QFF (50% rat chow + 50% dehydrated quinoa seeds) and exposed or not to restraint stress protocol (2 h/day; 15 days). Four experimental groups were used: Non-stressed (rat chow), Non-stressed + QFF, Stressed (rat chow) and Stressed + QFF. Weight gain, locomotor activity (open field), anxiety (elevated plus maze, light-dark box), spatial memory (Y-maze), and dendritic length in the hippocampus were measured in all animals. QFF intake did not influence anxiety-like behaviors, while the memory of stressed rats fed with QFF improved compared to those fed with rat chow. Additionally, QFF intake mitigated the stress-induced dendritic atrophy in pyramidal neurons located in the CA3 area of the hippocampus. The results suggest that a quinoa-supplemented diet could play a protective role in the memory of chronically stressed rats.
Assuntos
Chenopodium quinoa , Ratos , Animais , Masculino , Ratos Sprague-Dawley , Aprendizagem em Labirinto , Suplementos Nutricionais , Hipocampo/fisiologia , Estresse Psicológico/psicologiaRESUMO
INTRODUCTION: The treatment of brain dead donors with combined hormonal resuscitation protocols, including methylprednisolone (MP) and triiodothyronine (T3), among others, was developed to increase the viability and function of transplanted organs, primarily heart and lung. Even when it has regarded successful results in term of donors and organs recovery, its effects over specific parameters in organs like the liver are unknown. MATERIAL AND METHODS: Male Sprague-Dawley rats were pretreated with MP (0.34 mg/kg) and/or T3 (0.05 mg/kg) or their vehicles, and then subjected to partial hepatectomy of 70%. Three experimental groups and their respective controls were conformed: a. T3; b. NaOH; c. MP; d. vMP; e. MP+T3 and f. vMP+NaOH. The groups were evaluated at 0, 16, 24, 72 and 120 h post surgery. The effects of this protocol on regeneration, liver mass recovery, liver injury, oxidative stress and liver function were analyzed. RESULTS: MP+T3 pretreatment does not deleteriously affect liver regeneration after partial hepatectomy, as shown in the curve of total mass recovery, Ki67 staining and mitosis counting, and does not alter liver function. In addition, the treatment modestly decreases oxidative stress and liver injury, as evidenced by transaminases levels, histological analysis and oxidized proteins content. CONCLUSION: These preclinical results indicate that MP+T3 is harmless for liver tissue regeneration post hepatectomy and additionally exhibits anti-inflammatory and antioxidant effects; therefore, it would not be contraindicated for the treatment of multiorgan donors in brain death and particularly, if the occurrence of small for size syndrome is suspected.
Assuntos
Anti-Inflamatórios/farmacologia , Hepatectomia , Hepatite/prevenção & controle , Regeneração Hepática/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/cirurgia , Metilprednisolona/farmacologia , Tri-Iodotironina/farmacologia , Animais , Antioxidantes/farmacologia , Proliferação de Células/efeitos dos fármacos , Hepatectomia/efeitos adversos , Hepatite/etiologia , Antígeno Ki-67/metabolismo , Fígado/metabolismo , Fígado/patologia , Fígado/fisiopatologia , Masculino , Índice Mitótico , Necrose , Estresse Oxidativo/efeitos dos fármacos , Carbonilação Proteica/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
Non-alcoholic fatty liver disease (NAFLD) is triggered by a nutritional-metabolic alteration characterized by triacylglicerides acumulation, insulin resistance (IR), oxidative stress and depletion of polyunsaturated fatty acid (PUFA). The n-3 PUFA, such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, would be hepatoprotective against the development of NAFLD by stimulating lipolysis and inhibit lipogenesis. So, fish oil supplementation (EPA + DHA) prevents HFD-induced NAFLD. In this context, the aim of this study is to evaluate the correlation between liver oxidative stress with IR and levels of PUFA in supplemented mice. Male mice C57BL/6J (n = 9) were fed for 12th week: a) control diet (20% protein, 70% carbohydrate, 10% lipids), b) control diet and fish oil supplementation (200 mg EPA+DHA/kg/day), c) high fat diet (20% protein, 20% carbohydrate, 60% lipids), and d) high fat diet and fish oil supplementation. Liver steatosis (histology), insulin resistance (HOMA), liver oxidative stress (GSH/GSSG, carbonyl protein and 8-isoprostanes) and liver fatty acid content were evaluated. The significant decrease in liver oxidative stress parameters (p < 0.05, ANOVA followed by Newman Keuls test) were correlated (Pearson test) with HOMA and levels of PUFA, along with the hepatoprotection observed. It concludes that prevention of NAFLD by supplementation with fish oil (EPA+DHA) is dependent of the prevention of liver oxidative stress, IR and PUFA depletion.
Assuntos
Gorduras Insaturadas na Dieta/administração & dosagem , Suplementos Nutricionais , Fígado Gorduroso/prevenção & controle , Óleos de Peixe/administração & dosagem , Resistência à Insulina/fisiologia , Estresse Oxidativo/fisiologia , Animais , Fígado Gorduroso/metabolismo , Fígado Gorduroso/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não AlcoólicaRESUMO
White adipose tissue (AT) dysfunction plays an important role in the development of cardiometabolic alterations associated with obesity. AT dysfunction is characterized by the loss of the expansion capacity of the AT, an increment in adipocyte hypertrophy, and changes in the secretion profile of adipose cells, associated with accumulation of macrophages and inflammation. Since not all people with an excess of adiposity develop comorbidities, it is necessary to find simple tools that can evidence AT dysfunction and allow the detection of those people with the potential to develop metabolic alterations. This review focuses on the current pathophysiological mechanisms of white AT dysfunction and emerging measurements to assess its functionality.
Assuntos
Tecido Adiposo Branco , Obesidade , Humanos , Obesidade/metabolismo , Tecido Adiposo Branco/metabolismo , Adiposidade , Adipócitos/metabolismo , Inflamação/metabolismo , Tecido Adiposo/metabolismoRESUMO
OBJECTIVES: An altered retinol metabolism might play a role in the development of nonalcoholic fatty liver disease (NAFLD). Tocopherols (TF) modulate metabolic pathways and have been proposed as a complementary treatment of obesity-induced metabolic alterations. Moreover, there is evidence suggesting that TF may modulate retinol metabolism. The aim of this study was to evaluate whether the dietary supplementation of α- and γ-TF modulates the expression of hepatic retinaldehyde dehydrogenases, RALDH1, RALDH2, and RALDH3 (involved in retinol metabolism) and, lipogenic factors sterol regulatory element binding protein-1c (SREBP-1c) and cluster differentiation 36 (CD36) in an animal model of diet-induced NAFLD. METHODS: Male C57BL/6J mice were divided into four groups: a control diet (CD) group (10% fat, 20% protein, 70% carbohydrates); a CD + TF group (α-tocopherol: 0.7 mg·kg·d-1, γ-tocopherol: 3.5 mg·kg·d-1); a high-fat diet (HFD) group (60% fat, 20% protein, 20% carbohydrates); and a HFD + TF group (0.01 mL·g body weight·d-1), for 12 wk. General parameters (body-adipose tissue weight, glucose-triacylglyceride serum levels), liver steatosis (histology, liver triacylglycerides content), and hepatic RALDH1, RALDH2, RALDH3, SREBP-1c and CD36 (qPCR, quantitative polymerase chain reaction; IHQ, immunohistochemistry) were measured. RESULTS: TF supplementation in HFD-fed mice decreased the presence of lipid vesicles (90%) and total lipid content (75%) and downregulated the expression of RALDH1, RALDH3, SREBP-1c, and CD36. CONCLUSIONS: The present study demonstrated that α- and γ-TF (1:5 ratio) might play a role in modulating retinol metabolism in the prevention of NAFLD induced by a HFD.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Retinaldeído , Aldeído Oxirredutases/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/metabolismo , Retinaldeído/metabolismo , Tocoferóis/metabolismoRESUMO
Advanced glycation end products (AGEs) may be associated with nonalcoholic fatty liver disease (NAFLD) from stimulation of oxidative stress, inflammation, and fibrosis. We hypothesized that patients with NAFLD would have a lower concentration of soluble AGEs receptor and higher quantity of serum and liver AGEs and an increase in hepatic smooth muscle actin alpha (α-SMA) and transforming growth factor beta 1 (TGF-ß1) compared with a control group. We compared the presence of hepatic and serum AGEs, AGE soluble receptor (sRAGE), and markers associated with hepatic damage between NAFLD patients and controls without disease. Histological characteristics, plasma biochemical parameters, serum AGEs, serum receptor sRAGE, and liver proteins (α-SMA, TGF-ß1, AGEs, immunohistochemistry) were assessed in participants aged 18 to 65 years, with NAFLD (simple steatosis [SS]: n = 7; steatohepatitis [NASH]: n = 15) and controls (n = 11). NASH patients presented higher glycated hemoglobin levels (%) (5.7; 5.4-6.3) compared with SS (5.4; 5.2-5.7) and controls (5.4; 5.3-5.5). The NAFLD activity score (NAS) for NASH patients was 4.9 ± 1.3; for SS patients, 2.0 ± 1.0. NASH patients showed higher hepatic AGEs, TGF-ß1, and α-SMA compared with SS and control groups. The NAS score indicates that patients with 5 to 8 had higher hepatic AGEs, TGF-ß1, and α-SMA compared with a NAS of 1 to 4 and 0. For α-SMA, a NAS of 1 to 4 was higher than NAS 0. No difference was found in serum AGEs and sRAGE between groups. Higher hepatic AGEs, TGF-ß1, and α-SMA were observed with increasing disease severity (according to NAS); therefore, endogenous liver AGEs may participate in hepatic damage progression.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Biomarcadores , Produtos Finais de Glicação Avançada , Humanos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fator de Crescimento Transformador beta1/metabolismoRESUMO
OBJECTIVES: The aim of this study was to evaluate the effect of the dietary supplementation of an alpha- and gamma-tocopherol mixture (1:5 ratio) in the adipose tissue expansion, hepatic steatosis, and expression of inflammatory markers induced by consumption of a high-fat diet (HFD) in mice. METHODS: Male C57BL/6 J mice were fed for 12 wk and divided into the following: 1) control diet (CD; 10% fat, 20% protein, 70% carbohydrates); 2) CD + TF (CD plus alpha-tocopherol: 0.7 mg/kg/d, gamma-tocopherol: 3.5 mg/kg/d); 3) HFD (60% fat, 20% protein, 20% carbohydrates); and 4) HFD + TF (HFD plus alpha-tocopherol: 0.7 mg/kg/d, gamma-tocopherol: 3.5 mg/kg/d). General parameters, adipocyte size, liver steatosis, adipose and hepatic tumor necrosis factor-α (TNF-α) and interleukin-1 ß (IL-1ß) expression, hepatic nuclear factor kappa B (NF-κB), and peroxisome proliferator-activated receptor α (PPAR-α) levels were evaluated. RESULTS: Tocopherol supplementation in HFD-fed mice showed a significant decrease in the body weight (19%) and adipose tissue weight (52%), adipose tissue/body weight ratio (36%), and serum triacylglycerols (56%); a 42% decrease (P < 0.05) of adipocyte size compared to HFD; attenuation of liver steatosis by decreasing (P < 0.05) lipid vesicles presence (90%) and total lipid content (75%); and downregulation of inflammatory markers (TNF-α and IL-1ß), along with an upregulation of hepatic PPAR-α expression and its downstream-regulated genes (ACOX and CAT-1), and an inhibition of hepatic NF-κB activation. CONCLUSION: The present study suggests that alpha- and gamma-tocopherol (1:5 ratio) supplementation attenuates the adipocyte enlargement, hepatic steatosis, and metabolic inflammation induced by HFD in association with PPAR-α/NF-κB modulation.
Assuntos
Dieta Hiperlipídica , Fígado Gorduroso , Tecido Adiposo , Animais , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Modelos Animais de Doenças , Fígado Gorduroso/etiologia , Fígado Gorduroso/prevenção & controle , Fígado , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Expansão de Tecido , gama-Tocoferol/farmacologiaRESUMO
Excess adipose tissue (AT) associates with inflammation and obesity-related diseases. We studied whether calcium-sensing receptor (CaSR)-mediated NLRP3 inflammasome activation in THP-1 macrophages elevates inflammation in LS14 preadipocytes, modeling deleterious AT cell crosstalk. THP-1 macrophages exposed to cinacalcet (CaSR activator, 2 µM, 4 h) showed elevated proinflammatory marker and NLRP3 inflammasome mRNA, pro-IL-1ß protein and caspase-1 activity, whereas preincubation with CaSR negative modulators prevented these effects. The key NLRP3 inflammasome component ASC was silenced (siRNA) in THP-1 cells, and inflammasome activation was evaluated (qPCR, Western blot, caspase-1 activity) or they were further cultured to obtain conditioned medium (CoM). Exposure of LS14 preadipocytes to CoM from cinacalcet-treated THP-1 elevated LS14 proinflammatory cytokine expression, which was abrogated by THP-1 inflammasome silencing. Thus, CaSR activation elevates THP-1-induced inflammation in LS14 preadipocytes, via macrophage NLRP3 inflammasome activation. Modulating CaSR activation may prevent deleterious proinflammatory cell crosstalk in AT, a promising approach in obesity-related metabolic disorders.
Assuntos
Inflamassomos/metabolismo , Inflamação/metabolismo , Macrófagos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Receptores de Detecção de Cálcio/metabolismo , Células THP-1/metabolismo , Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Caspase 1/metabolismo , Linhagem Celular , Citocinas/metabolismo , Humanos , Interleucina-1beta/metabolismo , Obesidade/metabolismo , RNA Mensageiro/metabolismoRESUMO
The effects of dietary Rosa mosqueta (RM, Rosa rubiginosa) oil, rich in α-linolenic acid, in the prevention of liver steatosis were studied in mice fed a high fat diet (HFD). C57BL/6j mice were fed either a control diet or HFD with or without RM oil for 12 weeks. The results indicate that RM oil supplementation decreases fat infiltration of the liver from 43.8% to 6.2%, improving the hepatic oxidative state, insulin levels, HOMA index, and both body weight and adipose tissue weight of HFD plus RM treated animals compared to HFD without supplementation. In addition, the DHA concentration in the liver was significantly increased in HFD fed mice with RM oil compared to HFD (3 vs. 1.6 g per 100 g FAME). The n-6/n-3 ratio was not significantly modified by treatment with RM. Our findings suggest that RM oil supplementation prevents the development of hepatic steatosis and the obese phenotype observed in HFD fed mice.
Assuntos
Fígado Gorduroso/prevenção & controle , Óleos de Plantas/metabolismo , Rosa/química , Animais , Glicemia/metabolismo , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/dietoterapia , Fígado Gorduroso/metabolismo , Humanos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Rosa/metabolismoRESUMO
Nonalcoholic fatty liver disease is characterized by an abnormal accumulation of triacylglycerides in the liver in absence of significant alcohol consumption. Under these conditions, it has been observed an impaired bioavailability of hepatic n-3 long-chain polyunsaturated fatty acids (LCPUFAs). The aim of this study was to test the reversion of the prosteatotic and proinflammatory effects of high-fat diet (HFD) in the mouse liver by changing to normocaloric diet and n-3 LCPUFA supplementation. Male C57BL/6J mice were given either control diet (CD) or HFD for 12 weeks. Control and HFD groups were divided into subgroups that continue with CD or subjected to CD plus n-3 LCPUFA for 8 additional weeks. After this time, blood and liver samples were taken and metabolic, morphologic, oxidative stress, inflammatory and signaling parameters were analyzed. The dietary change from HFD to a normocaloric diet with n-3 LCPUFA supplementation significantly reduced insulin resistance and liver steatosis when compared to switching HFD to normocaloric diet alone. In addition, HFD-induced increases in adiposity, adipocyte enlargement and liver oxidative stress and inflammatory cytokine expression were suppressed by n-3 LCPUFA to control values. Importantly, n-3 LCPUFA supplementation abolish HFD-induced enhancement in hepatic SREBP-1c/PPAR-α ratios, suggesting a change in the metabolic status of the liver from a lipogenic condition to one favoring fatty acid oxidation and steatosis attenuation. These findings may provide the rational basis for the use of normocaloric diets supplemented with n-3 LCPUFA in patients with liver steatosis.
Assuntos
Dieta Hiperlipídica , Ácidos Graxos Ômega-3/farmacologia , Fígado Gorduroso/tratamento farmacológico , PPAR alfa/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Animais , Sequência de Bases , Primers do DNA , Suplementos Nutricionais , Fígado Gorduroso/etiologia , Fígado Gorduroso/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da PolimeraseRESUMO
SCOPE: Dietary n-3 long-chain PUFAs (n-3 LCPUFAs) supplementation was studied in an HFD-induced (HFD is high-fat diet) steatosis and inflammation in relation to peroxisome proliferator-activated receptor alpha (PPAR-α) and nuclear factor κB (NF-κB) signaling. METHODS AND RESULTS: Male C57BL/6J mice received (i) control diet (10% fat, 20% protein, 70% carbohydrate), (ii) control diet plus n-3 LCPUFAs (daily doses of 108 mg/kg body weight of eicosapentaenoic acid plus 92 mg/kg body weight of docosahexaenoic acid), (iii) HFD (60% fat, 20% protein, 20% carbohydrate), or (iv) HFD plus n-3 LCPUFAs for 12 wk. PPAR-α, tumor necrosis factor alpha (TNF-α), and IL-1ß mRNA expression, acyl-CoA oxidase 1 (ACOX1), and carnitine-acyl-CoA transferase 1 (CAT-I) protein contents, and NF-κB DNA binding activity were measured. HFD significantly decreased liver PPAR-α, ACOX1, and CAT-I levels with NF-κB activation, higher TNF-α and IL-1ß expression, and steatosis development. These changes were either reduced or normalized to control values in animals subjected to HFD plus n-3 LCPUFAs, with establishment of an inverse association between NF-κB activation and PPAR-α mRNA expression (r = -0.66, p < 0.0001). CONCLUSION: Data presented indicate that n-3 LCPUFAs supplementation prevents liver steatosis and inflammation induced by HFD, with underlying mechanisms involving enhanced PPAR-α signaling and diminished NF-κB activation.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Ácidos Graxos Ômega-3/administração & dosagem , Fígado Gorduroso/prevenção & controle , NF-kappa B/metabolismo , PPAR alfa/metabolismo , Acil-CoA Oxidase/genética , Acil-CoA Oxidase/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Fígado Gorduroso/etiologia , Inflamação/etiologia , Inflamação/prevenção & controle , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Fígado/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/genética , Tamanho do Órgão , PPAR alfa/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Regulação para CimaRESUMO
Omega-3 (n-3) long-chain polyunsaturated fatty acids (n-3 LCPUFA) are associated with several physiological functions, suggesting that their administration may prevent non transmissible chronic diseases. Therefore, we investigate whether dietary n-3 LCPUFA supplementation triggers an antioxidant response preventing liver steatosis in mice fed a high fat diet (HFD) in relation to n-3 LCPUFA levels. Male C57BL/6J mice received (a) control diet (10% fat, 20% protein, 70% carbohydrate), (b) control diet plus n-3 LCPUFA (108 mg/kg/day eicosapentaenoic acid plus 92 mg/kg/day docosahexaenoic acid), (c) HFD (60% fat, 20% protein, 20% carbohydrate), or (d) HFD plus n-3 LCPUFA for 12 weeks. Parameters of liver steatosis, glutathione status, protein carbonylation, and fatty acid analysis were determined, concomitantly with insulin resistance and serum tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6 levels. HFD significantly increased total fat and triacylglyceride contents with macrovesicular steatosis, concomitantly with higher fasting serum glucose and insulin levels, HOMA, and serum TNF-α, IL-1ß, and IL-6. Reduced and total liver glutathione contents were diminished by HFD, with higher GSSG/GSH ratio and protein carbonylation, n-3 LCPUFA depletion and elevated n-6/n-3 ratio over control values. These changes were either reduced or normalized to control values in animals subjected to HFD and n-3 LCPUFA, with significant increased hepatic total n-3 LCPUFA content and reduced n-6/n-3 ratio being observed after n-3 LCPUFA supplementation alone. So, repletion of liver n-3 LCPUFA levels by n-3 LCPUFA dietary supplementation in HFD obese mice reduces hepatic lipid content, with concomitant antioxidant and anti-inflammatory responses favouring insulin sensitivity.
Assuntos
Suplementos Nutricionais , Ácidos Graxos Ômega-3/uso terapêutico , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/patologia , Fígado/patologia , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Citocinas/sangue , Dieta Hiperlipídica , Ácidos Graxos/metabolismo , Ácidos Graxos Ômega-3/farmacologia , Fígado Gorduroso/sangue , Fígado Gorduroso/induzido quimicamente , Insulina/sangue , Resistência à Insulina , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo , Triglicerídeos/metabolismoRESUMO
High dietary intake of n-6 fatty acids in relation to n-3 fatty acids may generate health disorders, such as cardiovascular and other chronic diseases. Fish consumption rich in n-3 fatty acids is low in Latin America, it being necessary to seek other alternatives to provide α-linolenic acid (ALA), precursor of n-3 LCPUFA (EPA and DHA). Two innovative oils were assayed, chia (Salvia hispanica) and rosa mosqueta (Rosa rubiginosa). This study evaluated hepatic bioconversion of ALA to EPA and DHA, expression of PPAR-α, acyl-Coenzyme A oxidase 1 (ACOX1) and carnitine acyltransferase I (CAT-I), and accumulation of EPA and DHA in plasma and adipose tissue in Sprague-Dawley rats. Three experimental groups were fed 21 days: sunflower oil (SFO, control); chia oil (CO); rosa mosqueta oil (RMO). Fatty acid composition of total lipids and phospholipids from plasma, hepatic and adipose tissue was assessed by gas-liquid chromatography and TLC. Expression of PPAR-α (RT-PCR) and ACOX1 and CAT-I (Western blot). CO and RMO increased plasma, hepatic and adipose tissue levels of ALA, EPA and DHA and decreased n-6:n-3 ratio compared to SFO (p < 0.05, One-way ANOVA and Newman-Keuls test). CO increased levels of ALA and EPA compared to RMO (p < 0.05). No significant differences were observed for DHA levels. CO also increased the expression of PPAR-α, ACOX1 and CAT-I. Only CAT-I levels were increased by RO. CO and RMO may be a nutritional alternative to provide ALA for its bioconversion to EPA and DHA, and to increase the expression of PPAR-α, ACOX1 and CAT-I, especially CO-oil.