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Altered hepatic mitochondrial fatty acid ß-oxidation and associated tricarboxylic acid (TCA) cycle activity contributes to lifestyle-related diseases, and circulating biomarkers reflecting these changes could have disease prognostic value. This study aimed to determine hepatic and systemic changes in TCA-cycle-related metabolites upon the selective pharmacologic enhancement of mitochondrial fatty acid ß-oxidation in the liver, and to elucidate the mechanisms and potential markers of hepatic mitochondrial activity. Male Wistar rats were treated with 3-thia fatty acids (e.g., tetradecylthioacetic acid (TTA)), which target mitochondrial biogenesis, mitochondrial fatty acid ß-oxidation, and ketogenesis predominantly in the liver. Hepatic and plasma concentrations of TCA cycle intermediates and anaplerotic substrates (LC-MS/MS), plasma ketones (colorimetric assay), and acylcarnitines (HPLC-MS/MS), along with associated TCA-cycle-related gene expression (qPCR) and enzyme activities, were determined. TTA-induced hepatic fatty acid ß-oxidation resulted in an increased ratio of plasma ketone bodies/nonesterified fatty acid (NEFA), lower plasma malonyl-CoA levels, and a higher ratio of plasma acetylcarnitine/palmitoylcarnitine (C2/C16). These changes were associated with decreased hepatic and increased plasma pyruvate concentrations, and increased plasma concentrations of succinate, malate, and 2-hydroxyglutarate. Expression of several genes encoding TCA cycle enzymes and the malate-oxoglutarate carrier (Slc25a11), glutamate dehydrogenase (Gdh), and malic enzyme (Mdh1 and Mdh2) were significantly increased. In conclusion, the induction of hepatic mitochondrial fatty acid ß-oxidation by 3-thia fatty acids lowered hepatic pyruvate while increasing plasma pyruvate, as well as succinate, malate, and 2-hydroxyglutarate.
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Malatos , Ácido Pirúvico , Ratos , Animais , Masculino , Ratos Wistar , Malatos/metabolismo , Ácido Pirúvico/metabolismo , Cromatografia Líquida , Espectrometria de Massas em Tandem , Fígado/metabolismo , Ácidos Graxos/metabolismo , Oxirredução , Corpos Cetônicos/metabolismo , Succinatos/metabolismoRESUMO
This study investigated the effect of 50% diet restriction and its coadministration with krill oil (KO) or fish oil (FO) on glucose tolerance and insulin sensitivity in a rabbit model of obesity. Castrated male rabbits were 50% restricted fed and supplemented with KO or FO (600 mg omega-3 polyunsaturated fatty acids/daily) for 2 months. Simultaneously, two control groups were used: castrated, full-diet-fed and castrated, 50% restricted fed rabbits without additives restricted group (RG). The energy-restricted diet decreased final body weight in castrated male rabbits and improved most insulin sensitivity and ß-cell function indexes. Combining the same diet and KO or FO, further reduced fasting blood glucose levels. However, this feed regime significantly accelerated insulin secretion and reduced gene expression of insulin receptor substrate-1, pyruvate kinase and 3-hydroxy-3-methylglutaryl-CoA synthase 2. This was manifested by reduced dynamic insulin sensitivity, assessment homoeostasis-ß-cell function indices and increased glucose elimination rate to levels comparable to or above the obese animals. Aspartate and alanine aminotransferases enzyme activities were raised more than those in the obese group. Surprisingly, KO and FO administration downregulated acetyl-coenzyme A oxidase and carnitine palmitoyltransferase 2 messenger RNA gene expression compared to the RG. In conclusion, we can assume that a better effect on insulin sensitivity and glucose tolerance was observed in the diet restriction alone than in the coadministration of KO or FO when animals are exposed to highly obesity predisposing factors. These effects could be at least in part ascribed to the modified gene expression levels of some critical enzymes and factors involved in liver glucose metabolism and ß-oxidation.
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Euphausiacea , Resistência à Insulina , Coelhos , Masculino , Animais , Óleos de Peixe/farmacologia , Obesidade/metabolismo , Obesidade/veterinária , Insulina , Fígado/metabolismo , Castração/veterinária , Dieta , Glucose/metabolismoRESUMO
Hepatic mitochondrial function, APOC-III, and LPL are potential targets for triglyceride (TG)-lowering drugs. After 3 weeks of dietary treatment with the compound 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA), the hepatic mitochondrial FA oxidation increased more than 5-fold in male Wistar rats. Gene expression analysis in liver showed significant downregulation of APOC-III and upregulation of LPL and the VLDL receptor. This led to lower hepatic (53%) and plasma (73%) TG levels. Concomitantly, liver-specific biomarkers related to mitochondrial biogenesis and function (mitochondrial DNA, citrate synthase activity, and cytochrome c and TFAM gene expression) were elevated. Interestingly, 1-triple TTA lowered plasma acetylcarnitine levels, whereas the concentration of ß-hydroxybutyrate was increased. The hepatic energy state was reduced in 1-triple TTA-treated rats, as reflected by increased AMP/ATP and decreased ATP/ADP ratios, whereas the energy state remained unchanged in muscle and heart. The 1-triple TTA administration induced gene expression of uncoupling protein (UCP)2 and UCP3 in liver. In conclusion, the 1-triple TTA-mediated clearance of blood TG may result from lowered APOC-III production, increased hepatic LPL gene expression, mitochondrial FA oxidation, and (re)uptake of VLDL facilitating drainage of FAs to the liver for ß-oxidation and production of ketone bodies as extrahepatic fuel. The possibility that UCP2 and UCP3 mediate a moderate degree of mitochondrial uncoupling should be considered.
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Apolipoproteína C-III/metabolismo , Ácidos Graxos/metabolismo , Fígado/metabolismo , Mitocôndrias Hepáticas/metabolismo , Proteínas de Desacoplamento Mitocondrial/metabolismo , Triglicerídeos/sangue , Ácido Acético/química , Ácido Acético/farmacologia , Acetilcarnitina/metabolismo , Animais , Carnitina/metabolismo , Metabolismo Energético/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Mitocôndrias Hepáticas/efeitos dos fármacos , Oxirredução , Ratos , Ratos Wistar , Triglicerídeos/metabolismoRESUMO
Background: Olanzapine is an orexigenic antipsychotic drug associated with serious metabolic adverse effects in humans. Development of valid rodent models for antipsychotic-induced metabolic adverse effects is hampered by the fact that such effects occur in females only. Estradiol is a predominant female hormone that regulates energy balance. We hypothesized that the female-specific hyperphagia and weight gain induced by olanzapine in the rat are dependent on the presence of estrogens. Methods: Female sham-operated or ovariectomized rats were treated with a single injection of olanzapine depot formulation. Food intake, body weight, plasma lipids, lipogenic gene expression, energy expenditure, and thermogenic markers including brown adipose tissue uncoupling protein 1 protein levels were measured. Olanzapine was also administered to ovariectomized rats receiving estradiol replacement via the subcutaneous (peripheral) or intracerebroventricular route. Results: Orexigenic effects of olanzapine were lost in ovariectomized female rats. Ovariectomized rats treated with olanzapine had less pronounced weight gain than expected from their food intake. Accordingly, brown adipose tissue temperature and protein levels of uncoupling protein 1 were elevated. Replacement in ovariectomized rats with either peripherally or centrally administered estradiol reduced food intake and body weight. Cotreatment with olanzapine blocked the anorexigenic effect of peripheral, but not central estradiol. Conclusions: Our results indicate that the ovarian hormone estradiol plays an important role in olanzapine-induced hyperphagia in female rats and pinpoint the complex effects of olanzapine on the balance between energy intake and thermogenesis.
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Antipsicóticos/farmacologia , Benzodiazepinas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Ovário/fisiologia , Proteína Desacopladora 1/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Energia/efeitos dos fármacos , Estradiol/metabolismo , Feminino , Injeções Intraventriculares , Lipídeos/sangue , Olanzapina , Ovariectomia , Ovário/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Proteína Desacopladora 1/genética , Aumento de PesoRESUMO
BACKGROUND: Increased incidence of cardiovascular diseases (CVD) in both HIV infection and type 2 diabetes (T2D) compared to the general population has been described. Little is known about the combined effect of HIV infection and T2D on inflammation and endothelial function, both of which may contribute to elevated risk of CVD. METHODS: Cross-sectional study including 50 HIV-infected persons on combination anti-retroviral therapy (cART), with HIV RNA <200 copies/mL (n = 25 with T2D (HIV + T2D+), n = 25 without T2D (HIV + T2D-)) and 50 uninfected persons (n = 22 with T2D (HIV-T2D+) and n = 28 without T2D (HIV-T2D-)). Groups were matched on age and sex. High sensitive C-reactive protein (hsCRP) was used to determine inflammation (cut-off 3 mg/L). The marker of endothelial dysfunction asymmetric dimethylarginine (ADMA) was measured using high performance liquid chromatography. Trimethylamine-N-oxide (TMAO), a microbiota-dependent, pro-atherogenic marker was measured using stable isotope dilution LC/MS/MS. RESULTS: The percentage of HIV + T2D+, HIV + T2D-, HIV-T2D+, and HIV-T2D- with hsCRP above cut-off was 50%, 19%, 47%, and 11%, respectively. HIV + T2D+ had elevated ADMA (0.67 µM (0.63-0.72) compared to HIV + T2D- (0.60 µM (0.57-0.64) p = 0.017), HIV-T2D+ (0.57 µM (0.51-63) p = 0.008), and HIV-T2D- (0.55 µM (0.52-0.58) p < 0.001). No differences in TMAO between groups were found. However, a positive correlation between ADMA and TMAO was found in the total population (rs = 0.32, p = 0.001), which was mainly driven by a close correlation in HIV + T2D+ (rs = 0.63, p = 0.001). CONCLUSION: Elevated inflammation and evidence of endothelial dysfunction was found in HIV-infected persons with T2D. The effect on inflammation was mainly driven by T2D, while both HIV infection and T2D may contribute to endothelial dysfunction. Whether gut microbiota is a contributing factor to this remains to be determined.
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Doenças Cardiovasculares/etiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Endotélio Vascular/fisiopatologia , Infecções por HIV/fisiopatologia , Inflamação/etiologia , Arginina/análogos & derivados , Arginina/sangue , Biomarcadores/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/diagnóstico , Estudos de Casos e Controles , Cromatografia Líquida de Alta Pressão , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Feminino , Infecções por HIV/sangue , Infecções por HIV/complicações , Humanos , Inflamação/sangue , Inflamação/diagnóstico , Masculino , Metilaminas/sangue , Pessoa de Meia-Idade , Fatores de Risco , Espectrometria de Massas em TandemRESUMO
Rats are used as animal models in the study of antipsychotic-induced metabolic adverse effects, with oral drug administration yielding hyperphagia, weight gain and, in some cases, lipogenic effects. However, the rapid half-life of these drugs in rats, in combination with development of drug tolerance after a few weeks of treatment, has limited the validity of the model. In order to prevent fluctuating drug serum concentrations seen with daily repeated administrations, we injected female rats with a single intramuscular dose of long-acting olanzapine formulation. The olanzapine depot injection yielded plasma olanzapine concentrations in the range of those achieved in patients, and induced changes in metabolic parameters similar to those previously observed with oral administration, including increased food intake, weight gain and elevated plasma triglycerides. Moreover, the sensitivity to olanzapine was maintained beyond the 2-3 wk of weight gain observed with oral administration. In a separate olanzapine depot experiment, we aimed to clarify the role of hypothalamic AMP-activated protein kinase (AMPK) in olanzapine-induced weight gain, which has been subject to debate. Adenovirus-mediated inhibition of AMPK was performed in the arcuate (ARC) or the ventromedial hypothalamic (VMH) nuclei in female rats, with subsequent injection of olanzapine depot solution. Inhibition of AMPK in the ARC, but not in the VMH, attenuated the weight-inducing effect of olanzapine, suggesting an important role for ARC-specific AMPK activation in mediating the orexigenic potential of olanzapine. Taken together, olanzapine depot formulation provides an improved mode of drug administration, preventing fluctuating plasma concentrations, reducing handling stress and opening up possibilities to perform complex mechanistic studies.
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Antipsicóticos/efeitos adversos , Benzodiazepinas/efeitos adversos , Doenças Metabólicas/induzido quimicamente , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Tecido Adiposo/metabolismo , Animais , Antipsicóticos/administração & dosagem , Antipsicóticos/sangue , Núcleo Arqueado do Hipotálamo/enzimologia , Benzodiazepinas/administração & dosagem , Benzodiazepinas/sangue , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Modelos Animais de Doenças , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Fígado/metabolismo , Doenças Metabólicas/sangue , Olanzapina , Ratos , Triglicerídeos/sangue , Núcleo Hipotalâmico Ventromedial/enzimologia , Aumento de Peso/efeitos dos fármacosRESUMO
PURPOSE: Biological effects of marine oils, fish oil (FO) and krill oil (KO), are mostly attributed to the high content of n-3 polyunsaturated fatty acids (n-3 PUFAs), predominantly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The study was aimed to investigate the influence of FO and KO on lipid homeostasis and inflammation in an animal model of persistent low-grade exposure to human tumor necrosis factor α (hTNF-α) and to evaluate whether these effects depend on the structural forms of EPA and DHA [triacylglycerols (TAG) vs. phospholipids]. METHODS: Male C57BL/6 hTNF-α mice were fed for 6 weeks a high-fat control diet (24.50 % total fats, w/w) or high-fat diets containing either FO or KO at similar doses of n-3 PUFAs (EPA: 5.23 vs. 5.39 wt%, DHA: 2.82 vs. 2.36 wt% of total fatty acids). RESULTS: We found that KO, containing bioactive n-3 PUFAs in the form of phospholipids, was capable of modulating lipid metabolism by lowering plasma levels of TAG and cholesterol and stimulating the mitochondrial and peroxisomal fatty acid ß-oxidation, as well as improving the overall carnitine turnover. Though the administration of FO was not as effective as KO in the lowering of plasma TAG, FO significantly improved the levels of all cholesterol classes in plasma. Except from the increase in the levels of IL-17 in FO-fed mice and a trend to decrease in MCP-1 levels in KO-fed animals, the levels of pro-inflammatory cytokines were not substantially different between treatment groups. CONCLUSION: Our findings demonstrate that FO and KO are comparable dietary sources of n-3 PUFAs. However, when quantitatively similar doses of n-3 PUFAs are administered, KO seems to have a greater potential to promote lipid catabolism. The effect of dietary oils on the levels of inflammatory markers in hTNF-α transgenic mice fed a high-fat diet needs further investigations.
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Anti-Inflamatórios não Esteroides/uso terapêutico , Euphausiacea/química , Óleos de Peixe/uso terapêutico , Hipertrigliceridemia/prevenção & controle , Hipolipemiantes/uso terapêutico , Metabolismo dos Lipídeos , Óleos/uso terapêutico , Animais , Carnitina/sangue , Carnitina/metabolismo , Citocinas/metabolismo , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/sangue , Ácidos Docosa-Hexaenoicos/metabolismo , Ácidos Docosa-Hexaenoicos/uso terapêutico , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/sangue , Ácido Eicosapentaenoico/metabolismo , Ácido Eicosapentaenoico/uso terapêutico , Humanos , Hipertrigliceridemia/sangue , Hipertrigliceridemia/etiologia , Hipertrigliceridemia/imunologia , Fígado/imunologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosfolipídeos/sangue , Fosfolipídeos/metabolismo , Triglicerídeos/sangue , Triglicerídeos/metabolismo , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Abnormalities in the Tri-Carboxylic-Acid (TCA) cycle have been documented in dementia. Through network analysis, TCA cycle metabolites could indirectly reflect known dementia-related abnormalities in biochemical pathways, and key metabolites might be associated with prognosis. This study analyzed TCA cycle metabolites as predictors of cognitive decline in a mild dementia cohort and explored potential interactions with the diagnosis of Lewy Body Dementia (LBD) or Alzheimer's Disease (AD) and APOE-ε4 genotype. We included 145 mild dementia patients (LBD = 59; AD = 86). Serum TCA cycle metabolites were analyzed at baseline, and partial correlation networks were conducted. Cognitive performance was measured annually over 5-years with the Mini-mental State Examination. Longitudinal mixed-effects Tobit models evaluated each baseline metabolite as a predictor of 5-years cognitive decline. APOE-ε4 and diagnosis interactions were explored. Results showed comparable metabolite concentrations in LBD and AD. Multiple testing corrected networks showed larger coefficients for a negative correlation between pyruvate - succinate and positive correlations between fumarate - malate and citrate - Isocitrate in both LBD and AD. In the total sample, adjusted mixed models showed significant associations between baseline citrate concentration and longitudinal MMSE scores. In APOE-ε4 carriers, baseline isocitrate predicted MMSE scores. We conclude that, in mild dementia, serum citrate concentrations could be associated with subsequent cognitive decline, as well as isocitrate concentrations in APOE-ε4 carriers. Downregulation of enzymatic activity in the first half of the TCA cycle (decarboxylating dehydrogenases), with upregulation in the latter half (dehydrogenases only), might be indirectly reflected in serum TCA cycle metabolites' networks.
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Doença de Alzheimer , Demência , Doença por Corpos de Lewy , Humanos , Doença de Alzheimer/genética , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/psicologia , Isocitratos , Corpos de Lewy , Ácidos Carboxílicos , Apolipoproteínas E , Oxirredutases , CogniçãoRESUMO
Metabolic adverse effects such as weight gain and dyslipidaemia represent a major concern in treatment with several antipsychotic drugs, including olanzapine. It remains unclear whether such metabolic side-effects fully depend on appetite-stimulating actions, or whether some dysmetabolic features induced by antipsychotics may arise through direct perturbation of metabolic pathways in relevant peripheral tissues. Recent clinical and preclinical studies indicate that dyslipidaemia could occur independently of weight gain. Using a rat model, we showed that subchronic treatment with olanzapine induces weight gain and increases adipose tissue mass in rats with free access to food. This effect was also observed for aripiprazole, considered metabolically neutral in the clinical setting. In pair-fed rats with limited food access, neither olanzapine nor aripiprazole induced weight gain. Interestingly, olanzapine, but not aripiprazole, induced weight-independent elevation of serum triglycerides, accompanied by up-regulation of several genes involved in lipid biosynthesis, both in liver and in adipose tissues. Our findings support the existence of tissue-specific, weight-independent direct effects of olanzapine on lipid metabolism.
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Antipsicóticos/farmacologia , Benzodiazepinas/farmacologia , Lipogênese/efeitos dos fármacos , Piperazinas/farmacologia , Quinolonas/farmacologia , Triglicerídeos/sangue , Aumento de Peso/efeitos dos fármacos , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Antipsicóticos/toxicidade , Aripiprazol , Benzodiazepinas/toxicidade , Peso Corporal/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica , Hiperfagia/sangue , Hiperfagia/induzido quimicamente , Metabolismo dos Lipídeos/efeitos dos fármacos , Olanzapina , Piperazinas/toxicidade , Quinolonas/toxicidade , Ratos , Ratos Sprague-DawleyRESUMO
Background: Acylcarnitines are essential for mitochondrial fatty acid oxidation. Earlier studies suggest that impaired energy metabolism may be implicated in the pathogenesis of microvascular angina. We explored metabolites from the carnitine pathway as predictors of cardiovascular disease (CVD) - and all-cause mortality among patients with non-obstructive coronary artery disease (NOCAD). Methods: A total of 1046 patients with suspected stable coronary syndrome underwent coronary angiography during 2000-2004, with findings of NOCAD. Serum levels of 8 selected carnitine metabolites were analyzed through liquid chromatography tandem mass spectrometry. Associations with CVD- and all-cause mortality were assessed by multivariable Cox regression models. Results: Median age at inclusion was 57 years. 51.5% were men. During median (25th- 75th percentiles), 14.1 (13.2-15.4) years of follow-up, 5.7% of the participants died from CVD and the incidence of all-cause mortality was 17.3%. Serum acetyl, octanoyl- and palmitoylcarnitine predicted CVD mortality with multivariable HR and 95% CI (per SD increment log transformed) of 1.36 (1.01-1.83), 1.49 (1.15-1.93) and 2.07 (1.49-2.85), p ≤ 0.04, respectively. Higher serum acetyl- and palmitoylcarnitines were also associated with increased risk of all-cause mortality (HR (95% CI): 1.27 (1.01-1.50), and 1.51 (1.26-1.81), p ≤ 0.007. Baseline levels of the precursors trimethyllysine and Æ´-butyrobetaine, carnitine or the odd chained propionylcarnitine and (iso)valerylcarnitine were not associated with adverse outcomes. Conclusion: Elevated serum even-chained acylcarnitines predicted adverse long-term prognosis in NOCAD. The strongest risk estimates were observed for palmitoylcarnitine, which predicted both CVD- and all-cause mortality after extensive multivariable adjustments. Underlying pathomechanisms should be further elucidated.
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Fatty liver diseases are a major health threat across the western world, leading to cirrhosis and premature morbidity and mortality. Recently, a correlation between the base excision repair enzyme SMUG1 and metabolic homeostasis was identified. As the molecular mechanisms remain unknown, we exploited a SMUG1-knockout mouse model to gain insights into this association by characterizing the liver phenotype in young vs old SMUG1-null mice. We observed increased weight and fat content in one-year old animals, with altered activity of enzymes important for fatty acids influx and uptake. Consistently, lipidomic profiling showed accumulation of free fatty acids and triglycerides in SMUG1-null livers. Old SMUG1-knockout mice also displayed increased hepatocyte senescence and DNA damage at telomeres. Interestingly, RNA sequencing revealed widespread changes in the expression of lipid metabolic genes already in three months old animals. In summary, SMUG1 modulates fat metabolism favouring net lipogenesis and resulting in development of a fatty liver phenotype.
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Fígado Gorduroso , Uracila-DNA Glicosidase , Camundongos , Animais , Uracila-DNA Glicosidase/metabolismo , Fígado Gorduroso/metabolismo , Camundongos Knockout , Fenótipo , Homeostase , Fígado/metabolismoRESUMO
[This corrects the article DOI: 10.3389/fgene.2019.00536.].
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OBJECTIVE: Discovery of specific markers that reflect altered hepatic fatty acid oxidation could help to detect an individual's risk of fatty liver, type 2 diabetes and cardiovascular disease at an early stage. Lipid and protein metabolism are intimately linked, but our understanding of this crosstalk remains limited. METHODS: In male Wistar rats, we used synthetic fatty acid analogues (3-thia fatty acids) as a tool to induce hepatic fatty acid oxidation and mitochondrial biogenesis, to gain new insight into the link between fatty acid oxidation, amino acid metabolism and TCA cycle-related intermediate metabolites in liver and plasma. RESULTS: Rats treated with 3-thia fatty acids had 3-fold higher hepatic, but not adipose and skeletal muscle, expression of the thioesterase 3-hydroxyisobutyryl-CoA hydrolase (Hibch), which controls the formation of 3-hydroxyisobutyrate (3-HIB) in the valine degradation pathway. Consequently, 3-thia fatty acid-stimulated hepatic fatty acid oxidation and ketogenesis was accompanied by decreased plasma 3-HIB and increased methylmalonic acid (MMA) concentrations further downstream in BCAA catabolism. The higher plasma MMA corresponded to higher MMA-CoA hydrolase activity and hepatic expression of GTP-specific succinyl-CoA synthase (Suclg2) and succinate dehydrogenase (Sdhb), and lower MMA-CoA mutase activity. Plasma 3-HIB correlated positively to plasma and hepatic concentrations of TAG, plasma total fatty acids, plasma NEFA and insulin/glucose ratio, while the reverse correlations were seen for MMA. CONCLUSION: Our study provides new insight into TCA cycle-related metabolic changes associated with altered hepatic fatty acid flux, and identifies 3-HIB and MMA as novel circulating markers reflective of mitochondrial ß-oxidation in male Wistar rats.
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Ácidos Graxos/metabolismo , Hidroxibutiratos/sangue , Ácido Metilmalônico/sangue , Mitocôndrias Hepáticas/metabolismo , Animais , Hidroxibutiratos/metabolismo , Resistência à Insulina , Masculino , Ácido Metilmalônico/metabolismo , Oxirredução , Ratos WistarRESUMO
OBJECTIVES: Recent studies suggest that activin A, a member of the transforming growth factor (TGF) superfamily, is involved in the pathogenesis of liver disorders. We sought to explore its possible role in non-alcoholic fatty liver disease (NAFLD). METHODS: Serum levels of activin A and its natural inhibitor, follistatin, were measured in patients with NAFLD (n=70) and in control subjects (n=30). Gene expression was quantified in liver biopsies obtained from patients with NAFLD (n=13) and controls (n=6). Effects of activin A were examined in Huh7 (human hepatoma cell line) hepatocytes. RESULTS: Patients with NAFLD had significantly elevated serum levels of activin A and follistatin compared with healthy controls. In patients with non-alcoholic steatohepatitis (NASH, n=38), there were particularly high levels of activin A that were significantly related to the degree of hepatic fibrosis. Liver biopsies from NAFLD patients showed a markedly increased activin A-follistatin mRNA ratio, indicating increased hepatic activin A activity. In hepatocytes, activin A enhanced the expression of collagen and TGF-beta(1), promoted matrix metalloproteinase activity, induced mitochondrial beta-oxidation, downregulated fatty acid (FA) synthase activity, promoted decreased weight percentage of saturated FAs, and altered the composition of polyunsaturated FAs. CONCLUSIONS: Our findings support the complex role of activin A in the pathogenesis of NAFLD, involving effects on fibrosis and lipid accumulation.
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Ativinas/sangue , Fígado Gorduroso/sangue , Folistatina/sangue , Cirrose Hepática/sangue , Ativinas/metabolismo , Adulto , Linhagem Celular Tumoral , Fígado Gorduroso/fisiopatologia , Feminino , Folistatina/metabolismo , Expressão Gênica , Humanos , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVE: This study investigated the potential additive or synergistic effect of fish oil (FO) and fish protein hydrolysate (FPH) on cholesterol concentration in plasma and the liver. METHODS: Male Wistar rats were fed high-fat diets (30% fat, 20% protein, wt/wt) containing FO (5%), FPH (10%), a combination of FO and FPH, or a high-fat control diet. After 7 wk of feeding, the rats were fasted for 12 h before lipid levels in plasma and the liver and hepatic activities of acyl-coenzyme A:cholesterol acyltransferase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and fatty acid synthase were measured. RESULTS: The combination of FO and FPH in the diet profoundly reduced the plasma cholesterol level, mainly due to lowering of high-density lipoprotein cholesterol, whereas the hepatic total cholesterol concentration was elevated compared with control rats and rats fed diets containing FPH or FO alone. The elevated cholesterol concentration in the liver was caused by an increased amount of cholesteryl esters and was in correlation to an increased activity of acyl-coenzyme A:cholesterol acyltransferase. There was a reduced fatty acid synthase activity that could lead to a reduced lipogenesis in the rats fed a combination of FO and FPH. CONCLUSION: A dietary combination of FO and FPH resulted in lower levels of plasma cholesterol and higher levels of hepatic cholesterol compared with dietary FO or FPH alone. Further studies are warranted to confirm whether the hypocholesterolemic effect was due to a reduced secretion of very low-density lipoprotein from the liver.
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Anticolesterolemiantes/farmacologia , Colesterol/metabolismo , Óleos de Peixe/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Hidrolisados de Proteína/farmacologia , Acil Coenzima A/metabolismo , Animais , Anticolesterolemiantes/administração & dosagem , Colesterol/sangue , Sinergismo Farmacológico , Ácido Graxo Sintases/metabolismo , Óleos de Peixe/administração & dosagem , Hidroximetilglutaril-CoA Redutases/metabolismo , Metabolismo dos Lipídeos/fisiologia , Fígado/enzimologia , Masculino , Hidrolisados de Proteína/administração & dosagem , Distribuição Aleatória , Ratos , Ratos Wistar , Esterol O-Aciltransferase/metabolismoRESUMO
BACKGROUND: Anthocyanins may protect against cardiovascular related cognitive decline and dementia. OBJECTIVE: Open-label study to measure changes in serum lipids, glucose, glycosylated hemoglobin (HbA1c), and markers of inflammation after anthocyanin supplementation in people with increased risk of dementia. As a secondary endpoint we examined potential changes in a battery of cognitive test in the anthocyanin group (AG). A total of 27 individuals with mild cognitive impairment (MCI) (n = 8) or stable non-obstructive coronary artery disease (CAD) (n = 19) consumed two Medox® capsules, each containing 80 mg of natural purified anthocyanins, twice daily for 16 weeks. They provided blood samples and performed a short battery of cognitive tests. Twenty healthy normal controls (NC) (n = 20) provided blood samples, but did not receive any intervention and did not perform cognitive tests. RESULTS: There was a significant difference between groups for CCL-5/RANTES [regulated on activation, normal T-cell expressed and secreted (RANTES)]. In addition, total cholesterol and triglycerides were significantly increased in the AG. Improvements in memory and executive test scores were observed. No adverse effects were reported. CONCLUSION: The results of this pilot study were largely inconclusive with regard to the potential protective effects of anthocyanin supplementation. However, anthocyanins were well tolerated, and compliance was high. Larger, placebo-controlled studies to explore the potential effects of anthocyanins on dementia risk are encouraged. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier NCT02409446.
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INTRODUCTION: Peroxisome proliferator-activated receptors (PPARs) have been suggested to be involved in the regulation of one-carbon metabolism. Previously we have reported effects on plasma concentrations of metabolites along these pathways as well as markers of B-vitamin status in rats following treatment with a pan-PPAR agonist. Here we aimed to investigate the effect on these metabolites after specific activation of the PPARα and PPARγ subtypes. METHODS: For a period of 12 days, Male Wistar rats (n = 20) were randomly allocated to receive treatment with the PPARα agonist WY-14.643 (n = 6), the PPARγ agonist rosiglitazone (n = 6) or placebo (n = 8). The animals were sacrificed under fasting conditions, and plasma concentration of metabolites were determined. Group differences were assessed by one-way ANOVA, and planned comparisons were performed for both active treatment groups towards the control group. RESULTS: Treatment with a PPARα agonist was associated with increased plasma concentrations of most biomarkers, with the most pronounced differences observed for betaine, dimethylglycine, glycine, nicotinamide, methylnicotinamide, pyridoxal and methylmalonic acid. Lower levels were observed for flavin mononucleotide. Fewer associations were observed after treatment with a PPARγ agonist, and the most notable was increased plasma serine. CONCLUSION: Treatment with a PPARα agonist influenced plasma concentration of one-carbon metabolites and markers of B-vitamin status. This confirms previous findings, suggesting specific involvement of PPARα in the regulation of these metabolic pathways as well as the status of closely related B-vitamins.
Assuntos
Carbono/metabolismo , PPAR alfa/agonistas , Pirimidinas/farmacologia , Complexo Vitamínico B/sangue , Animais , Masculino , PPAR gama/agonistas , Ratos , Ratos Wistar , Rosiglitazona/farmacologia , Fatores de TempoRESUMO
A fatty acid analogue, 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA), was previously shown to have hypolipidemic effects in rats by targeting mitochondrial activity predominantly in liver. This study aimed to determine if 1-triple TTA could influence carbohydrate metabolism. Male Wistar rats were treated for three weeks with oral supplementation of 100 mg/kg body weight 1-triple TTA. Blood glucose and insulin levels, and liver carbohydrate metabolism gene expression and enzyme activities were determined. In addition, human myotubes and Huh7 liver cells were treated with 1-triple TTA, and glucose and fatty acid oxidation were determined. The level of plasma insulin was significantly reduced in 1-triple TTA-treated rats, resulting in a 32% reduction in the insulin/glucose ratio. The hepatic glucose and glycogen levels were lowered by 22% and 49%, respectively, compared to control. This was accompanied by lower hepatic gene expression of phosphenolpyruvate carboxykinase, the rate-limiting enzyme in gluconeogenesis, and Hnf4A, a regulator of gluconeogenesis. Gene expression of pyruvate kinase, catalysing the final step of glycolysis, was also reduced by 1-triple TTA. In addition, pyruvate dehydrogenase activity was reduced, accompanied by 10-15-fold increased gene expression of its regulator pyruvate dehydrogenase kinase 4 compared to control, suggesting reduced entry of pyruvate into the TCA cycle. Indeed, the NADPH-generating enzyme malic enzyme 1 (ME1) catalysing production of pyruvate from malate, was increased 13-fold at the gene expression level. Despite the decreased glycogen level, genes involved in glycogen synthesis were not affected in livers of 1-triple TTA treated rats. In contrast, the pentose phosphate pathway seemed to be increased as the hepatic gene expression of glucose-6-phosphate dehydrogenase (G6PD) was higher in 1-triple TTA treated rats compared to controls. In human Huh7 liver cells, but not in myotubes, 1-triple-TTA reduced glucose oxidation and induced fatty acid oxidation, in line with previous observations of increased hepatic mitochondrial palmitoyl-CoA oxidation in rats. Importantly, this work recognizes the liver as an important organ in glucose homeostasis. The mitochondrially targeted fatty acid analogue 1-triple TTA seemed to lower hepatic glucose and glycogen levels by inhibition of gluconeogenesis. This was also linked to a reduction in glucose oxidation accompanied by reduced PHD activity and stimulation of ME1 and G6PD, favouring a shift from glucose- to fatty acid oxidation. The reduced plasma insulin/glucose ratio indicate that 1-triple TTA may improve glucose tolerance in rats.
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Acetatos/farmacologia , Glicemia/análise , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Insulina/sangue , Fígado/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Animais , Linhagem Celular , Frutosefosfatos/metabolismo , Humanos , Fígado/metabolismo , Glicogênio Hepático/metabolismo , Masculino , Redes e Vias Metabólicas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , NADP/metabolismo , Palmitoil Coenzima A/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Ratos , Ratos WistarRESUMO
The exchange proteins directly activated by cAMP 1 and 2 (Epac1 and Epac2) are expressed in a cell specific manner in the liver, but their biological functions in this tissue are poorly understood. The current study was undertaken to begin to determine the potential roles of Epac1 and Epac2 in liver physiology and disease. Male C57BL/6J mice in which expression of Epac1 and/or Epac2 are deleted, were subjected to partial hepatectomy and the regenerating liver was analyzed with regard to lipid accumulation, cell replication and protein expression. In response to partial hepatectomy, deletion of Epac1 and/or Epac2 led to increased hepatocyte proliferation 36 h post surgery, and the transient steatosis observed in wild type mice was virtually absent in mice lacking both Epac1 and Epac2. The expression of the protein cytochrome P4504a14, which is implicated in hepatic steatosis and fibrosis, was substantially reduced upon deletion of Epac1/2, while a number of factors involved in lipid metabolism were significantly decreased. Moreover, the number of Küpffer cells was affected, and Epac2 expression was increased in the liver of wild type mice in response to partial hepatectomy, further supporting a role for these proteins in liver function. This study establishes hepatic phenotypic abnormalities in mice deleted for Epac1/2 for the first time, and introduces Epac1/2 as regulators of hepatocyte proliferation and lipid accumulation in the regenerative process.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Regeneração Hepática/fisiologia , Animais , Proliferação de Células/fisiologia , Fígado Gorduroso/metabolismo , Fibrose/metabolismo , Hepatectomia/métodos , Metabolismo dos Lipídeos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Fatty acid oxidation is a central fueling pathway for mitochondrial ATP production. Regulation occurs through multiple nutrient- and energy-sensitive molecular mechanisms. We explored if upregulated mRNA expression of the mitochondrial enzyme pyruvate dehydrogenase kinase 4 (PDK4) may be used as a surrogate marker of increased mitochondrial fatty acid oxidation, by indicating an overall shift from glucose to fatty acids as the preferred oxidation fuel. The association between fatty acid oxidation and PDK4 expression was studied in different contexts of metabolic adaption. In rats treated with the modified fatty acid tetradecylthioacetic acid (TTA), Pdk4 was upregulated simultaneously with fatty acid oxidation genes in liver and heart, whereas muscle and white adipose tissue remained unaffected. In MDA-MB-231 cells, fatty acid oxidation increased nearly three-fold upon peroxisome proliferator-activated receptor α (PPARα, PPARA) overexpression, and four-fold upon TTA-treatment. PDK4 expression was highly increased under these conditions. Further, overexpression of PDK4 caused increased fatty acid oxidation in these cells. Pharmacological activators of PPARα and AMPK had minor effects, while the mTOR inhibitor rapamycin potentiated the effect of TTA. There were minor changes in mitochondrial respiration, glycolytic function, and mitochondrial biogenesis under conditions of increased fatty acid oxidation. TTA was found to act as a mild uncoupler, which is likely to contribute to the metabolic effects. Repeated experiments with HeLa cells supported these findings. In summary, PDK4 upregulation implies an overarching metabolic shift towards increased utilization of fatty acids as energy fuel, and thus constitutes a sensitive marker of enhanced fatty acid oxidation.