RESUMO
Bile acid tauroursodeoxycholic (TUDCA), formed from the association of ursodeoxycholic acid (UDCA) with taurine, has already been shown to increase mitochondrial biogenesis and cell survival, in addition to reduce reticulum stress markers in different cell types. However, its mechanism of action upon insulin secretion control in obesity is still unknown. In this sense, we seek to clarify whether taurine, associated with bile acid, could improve the function of the pancreatic ß-cells exposed to fatty acids through the regulation of mitochondrial metabolism. To test this idea, insulin-producing cells (INS1-E) were exposed to a fatty acid mix containing 500 µM of each palmitate and oleate for 48 hours treated or not with 300 µM of TUDCA. After that, glucose-stimulated insulin secretion and markers of mitochondrial metabolism were evaluated. Our results showed that the fatty acid mix was efficient in inducing hyperfunction of INS1-E cells as observed by the increase in insulin secretion, protein expression of citrate synthase, and mitochondrial density, without altering cell viability. The treatment with TUDCA normalized insulin secretion, reducing the protein expression of citrate synthase, mitochondrial mass, and the mitochondrial membrane potential. This effect was associated with a decrease in the generation of mitochondrial superoxide and c-Jun N-terminal kinase (JNK) protein content. The findings are also consistent with the hypothesis that TUDCA normalizes insulin secretion by improving mitochondrial metabolism and redox balance. Thus, it highlights likely mechanisms of the action of this bile acid on the glycemic homeostasis reestablishment in obesity.
Assuntos
Ácidos e Sais Biliares , Células Secretoras de Insulina , Taurina , Citrato (si)-Sintase/metabolismo , Ácidos Graxos , Humanos , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Obesidade , Taurina/farmacologia , Ácido Tauroquenodesoxicólico/farmacologiaRESUMO
BACKGROUND AND AIMS: Malnutrition in the early stages of life may lead to changes in the glycemic metabolism during adulthood, such as pancreatic beta cells dysfunction and failure. Therefore, this study aimed to evaluate the effects of an in vitro amino acid restriction model on the function and viability of pancreatic beta cells. METHODS: Insulin-producing cells (INS-1E) were maintained in control or amino acid restricted culture medium containing 1 × or 0.25 × of amino acids, respectively, for 48 h. RESULTS: Amino acid restricted group showed lower insulin secretion and insulin gene expression, reduced mitochondrial oxygen consumption rate and reactive oxygen species production. Besides, amino acid restricted group also showed higher levels of endoplasmic reticulum stress and apoptosis markers and enhanced Akt phosphorylation. However, even with higher levels of apoptosis markers, amino acid restricted group did not show higher levels of cell death unless the PI3K/Akt pathway was inhibited. CONCLUSION: Amino acid restricted beta cell viability seems to be dependent on the PI3K/Akt pathway.
Assuntos
Aminoácidos , Células Secretoras de Insulina , Transdução de Sinais , Animais , Apoptose , Linhagem Celular , Sobrevivência Celular , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , RatosRESUMO
Malnutrition programs metabolism, favor dysfunction of ß cells. We aimed to establish an in vitro protocol of malnutrition, assessing the effect of amino acid restriction upon the ß cells. Insulin-producing cells INS-1E and pancreatic islets were maintained in RPMI 1640 medium containing 1× (Ctl) or 0.25× (AaR) of amino acids. We evaluated several markers of ß-cell function and viability. AaR Insulin secretion was reduced, whereas cell viability was unaltered. Calcium oscillations in response to glucose increased in AaR. AaR showed lower Ins1 RNAm, snap 25, and PKC (protein kinase C) protein content, whereas phospho-eIF2α was increased. AaR cells exposed to nutrient or chemical challenges displayed higher apoptosis rates. We showed that amino acid restriction programmed ß cell and induced functional changes. This model might be useful for the study of molecular mechanisms involved with ß-cell programming helping to establish novel therapeutic targets to prevent harmful outcomes of malnutrition.
Assuntos
Aminoácidos/metabolismo , Aminoácidos/farmacologia , Apoptose/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Animais , Cálcio/metabolismo , Linhagem Celular , Citoplasma/metabolismo , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos Endogâmicos C57BLRESUMO
The practice of physical exercise is highly indicated to prevent cardiovascular diseases and is directly related to the improvement of endothelial function and the regulation of arterial blood pressure. The objective of this study was to analyze the effect of physical exercise in vascular remodeling after FeCl3 chemically induced arterial injury on atherosclerotic mice. To analyze the effect of exercises on thrombus formation, LDL receptor-deficient mice were fed for 6â¯weeks with a high-fat diet and performed or not physical exercises for 2â¯weeks before the arterial injury. To verify endothelium recovery the animals were exercised or not 2â¯weeks before the injury, and 3â¯weeks after it, when the vessels were analyzed. In this work, we observed that physical exercises done only before arterial injury reduced thrombosis time, protected the endothelial layer, promoted the recruitment of CD34 positive progenitor cells, increased the level of eNOS and gelatinases activities and decreased the number of inflammatory cells in the vessel, but do not avoid the growth of neointima. Otherwise exercises done before and continued after injury, increased gelatinase activities, reduced lipid deposition in the aortic arch and prevented neointima formation. Thus, we could conclude that physical exercises are done before and continued after endothelial injury stimulate endothelial recovery by promoting endothelial cell growth, matrix remodeling and decreasing inflammation in the vessel wall.
Assuntos
Aterosclerose/terapia , Exercício Físico/fisiologia , Neointima/terapia , Trombose/terapia , Remodelação Vascular/fisiologia , Animais , Aterosclerose/patologia , Humanos , Masculino , CamundongosRESUMO
Nutrient malnutrition, during the early stages of development, may facilitate the onset of metabolic diseases later in life. However, the consequences of nutritional insults, such as a high-fat diet (HFD) after protein restriction, are still controversial. We assessed overall glucose homeostasis and molecular markers of mitochondrial function in the gastrocnemius muscle of protein-restricted mice fed an HFD until early adulthood. Male C57BL/6 mice were fed a control (14% protein-control diet) or a protein-restricted (6% protein-restricted diet) diet for 6 weeks. Afterward, mice received an HFD or not for 8 weeks (mice fed a control diet and HFD [CH] and mice fed a protein-restricted diet and HFD [RH]). RH mice showed lower weight gain and fat accumulation and did not show an increase in fasting plasma glucose and insulin levels compared with CH mice. RH mice showed higher energy expenditure, increased citrate synthase, peroxisome-proliferator-activated receptor gamma coactivator 1-alpha protein content, and higher levels of malate and α-ketoglutarate compared with CH mice. Moreover, RH mice showed increased AMPc-dependent kinase and acetyl coenzyme-A (CoA) carboxylase phosphorylation, lower intramuscular triacylglycerol content, and similar malonyl-CoA levels. In conclusion, protein undernourishment after weaning does not potentiate fat accumulation and insulin resistance in adult young mice fed an HFD. This outcome seems to be associated with increased skeletal muscle mitochondrial oxidative capacity and reduced lipids accumulation.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Glucose/metabolismo , Homeostase/fisiologia , Músculo Esquelético/metabolismo , Deficiência de Proteína/metabolismo , Animais , Metabolismo Energético/fisiologia , Resistência à Insulina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismoRESUMO
Taurine (Tau) restores ß-cell function in obesity; however, its action is lost in malnourished obese rodents. Here, we investigated the mechanisms involved in the lack of effects of Tau in this model. C57BL/6 mice were fed a control diet (CD) (14% protein) or a protein-restricted diet (RD) (6% protein) for 6 wk. Afterward, mice received a high-fat diet (HFD) for 8 wk [CD + HFD (CH) and RD + HFD (RH)] with or without 5% Tau supplementation after weaning on their drinking water [CH + Tau (CHT) and RH + Tau (RHT)]. The HFD increased insulin secretion through mitochondrial metabolism in CH and RH. Tau prevented all those alterations in CHT only. The expression of the taurine transporter (Tau-T), as well as Tau content in pancreatic islets, was increased in CH but had no effect on RH. Protein malnutrition programs ß cells and impairs Tau-induced restoration of mitochondrial metabolism and biogenesis. This may be associated with modulation of the expression of Tau-T in pancreatic islets, which may be responsible for the absence of effect of Tau in protein-malnourished obese mice.-Branco, R. C. S., Camargo, R. L., Batista, T. M., Vettorazzi, J. F., Borck, P. C., dos Santos-Silva, J. C. R., Boschero, A. C., Zoppi, C. C., Carneiro, E. M. Protein malnutrition blunts the increment of taurine transporter expression by a high-fat diet and impairs taurine reestablishment of insulin secretion.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Proteínas Alimentares/administração & dosagem , Insulina/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Deficiência de Proteína/metabolismo , Taurina/farmacologia , Animais , Linhagem Celular , Suplementos Nutricionais , Regulação da Expressão Gênica/fisiologia , Ilhotas Pancreáticas , Masculino , Glicoproteínas de Membrana/genética , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Endogâmicos C57BL , Taurina/administração & dosagemRESUMO
Pancreatic beta cell (ß) dysfunction is an outcome of malnutrition. We assessed the role of the amplifying pathway (AMP PATH) in ß cells in malnourished obese mice. C57Bl-6 mice were fed a control (C) or a low-protein diet (R). The groups were then fed a high-fat diet (CH and RH). AMP PATH contribution to insulin secretion was assessed upon incubating islets with diazoxide and KCl. CH and RH displayed increased glucose intolerance, insulin resistance and glucose-stimulated insulin secretion. Only RH showed a higher contribution of the AMP PATH. The mitochondrial membrane potential of RH was decreased, and ATP flux was unaltered. In RH islets, glutamate dehydrogenase (GDH) protein content and activity increased, and the AMP PATH contribution was reestablished when GDH was blunted. Thus, protein malnutrition induces mitochondrial dysfunction in ß cells, leading to an increased contribution of the AMP PATH to insulin secretion through the enhancement of GDH content and activity.
Assuntos
Envelhecimento/patologia , Insulina/metabolismo , Desnutrição Proteico-Calórica/metabolismo , Animais , Intolerância à Glucose/complicações , Intolerância à Glucose/metabolismo , Intolerância à Glucose/patologia , Glutamato Desidrogenase/metabolismo , Resistência à Insulina , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Camundongos Endogâmicos C57BL , Camundongos Obesos , Mitocôndrias/metabolismo , Desnutrição Proteico-Calórica/complicações , Desnutrição Proteico-Calórica/patologiaRESUMO
BACKGROUND: The recreational use of anabolic-androgenic steroids (AAS) has reached alarming levels among healthy people. However, several complications have been related to consumption of these drugs, including liver disorders. OBJECTIVE: To evaluate the prevalence of liver injuries in young Brazilian recreational AAS users. METHODS: Between February/2007 and May/2012 asymptomatic bodybuilders who were ≥18 years old and reported AAS use for ≥6 months were enrolled. All had clinical evaluations, abdominal ultrasound (AUS), and blood tests. RESULTS: 182 individuals were included in the study. The median age (interquartile range) was 26.0 years (22.0-30.0) and all were male. Elevated liver enzyme levels were observed in 38.5% (n = 70) of AAS users, and creatine phosphokinase was normal in 27.1% (n = 19) of them. Hepatic steatosis was observed by AUS in 12.1% of the sample. One individual had focal nodular hyperplasia and another had hepatocellular adenoma. One case each of hepatitis B and C virus infection was found. A diagnosis of toxic liver injury was suggested in 23 (12.6%) AAS users without a history of alcohol or other medications/drugs consumption, or evidence of other liver diseases. CONCLUSIONS/IMPORTANCE: Young Brazilian recreational AAS users presented a wide spectrum of liver injuries that included hepatotoxicity, fatty liver, and liver neoplasm. They also presented risk factors for liver diseases such as alcohol consumption and hepatitis B and C virus infection. The results suggest that the risk of AAS use for the liver may be greater than the esthetic benefits, and demonstrate the importance of screening AAS users for liver injuries.
Assuntos
Anabolizantes/efeitos adversos , Doença Hepática Induzida por Substâncias e Drogas/epidemiologia , Drogas Ilícitas/efeitos adversos , Fígado/patologia , Adulto , Brasil , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/patologia , Humanos , Masculino , Prevalência , Fatores de Risco , Adulto JovemRESUMO
Anabolic-androgenic steroids (AAS) are used to enhance physical performance and/or appearance. The aim of this study was to evaluate the influence of the concomitant use of alcohol, tobacco, cocaine, and AAS on blood lipid profiles of 145 asymptomatic male bodybuilders from the Northeast region of Brazil. Interviews, clinical exams, and serological evaluations were performed on all participants between 2007 and 2009. All subjects' self-reported use of testosterone or its derivatives, 118 individuals reported alcohol intake, 27-reported cigarette smoking, and 33 confirmed cocaine use. Four subjects were users of all drugs at the same time. Higher levels of total cholesterol and LDL-cholesterol were observed among concomitant users of alcohol, tobacco, cocaine, and AAS. The study's limitations are noted.