RESUMO
Maternal diabetes impairs fetal lung development. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors relevant in lipid homeostasis and lung development. This study aims to evaluate the effect of in vivo activation of PPARs on lipid homeostasis in fetal lungs of diabetic rats. To this end, we studied lipid concentrations, expression of lipid metabolizing enzymes and fatty acid composition in fetal lungs of control and diabetic rats i) after injections of the fetuses with Leukotriene B4 (LTB4, PPARα ligand) or 15deoxyΔ(12,14)prostaglandin J2 (15dPGJ2, PPARγ ligand) and ii) fed during pregnancy with 6% olive oil- or 6% safflower oil-supplemented diets, enriched with PPAR ligands were studied. Maternal diabetes increased triglyceride concentrations and decreased expression of lipid-oxidizing enzymes in fetal lungs of diabetic rats, an expression further decreased by LTB4 and partially restored by 15dPGJ2 in lungs of male fetuses in the diabetic group. In lungs of female fetuses in the diabetic group, maternal diets enriched with olive oil increased triglyceride concentrations and fatty acid synthase expression, while those enriched with safflower oil increased triglyceride concentrations and fatty acid transporter expression. Both olive oil- and safflower oil-supplemented diets decreased cholesterol and cholesteryl ester concentrations and increased the expression of the reverse cholesterol transporter ATP-binding cassette A1 in fetal lungs of female fetuses of diabetic rats. In fetal lungs of control and diabetic rats, the proportion of polyunsaturated fatty acids increased with the maternal diets enriched with olive and safflower oils. Our results revealed important changes in lipid metabolism in fetal lungs of diabetic rats, and in the ability of PPAR ligands to modulate the composition of lipid species relevant in the lung during the perinatal period.
Assuntos
Diabetes Gestacional/metabolismo , Leucotrieno B4/metabolismo , Metabolismo dos Lipídeos , Lipídeos/química , Pulmão/metabolismo , PPAR alfa/metabolismo , PPAR gama/metabolismo , Prostaglandina D2/análogos & derivados , Animais , Diabetes Gestacional/genética , Feminino , Feto/embriologia , Feto/metabolismo , Ligantes , Pulmão/química , Pulmão/embriologia , Masculino , Azeite de Oliva , PPAR alfa/genética , PPAR gama/genética , Óleos de Plantas/metabolismo , Gravidez , Prostaglandina D2/metabolismo , Ratos , Ratos Wistar , Óleo de Cártamo/metabolismoRESUMO
Metabolic alterations in obese and overweight mothers impact the placenta and the fetus, leading to anomalies in fetal growth and lipid accretion. The primary aim of the study was to examine the effect of a saturated fat-rich diet (FD) on growth, lipid accretion, and lipases, leptin and leptin receptor (ObR) expression in the placenta and fetal liver. We also aimed to find a role for fetal leptin in the modulation of placental and fetal liver lipase and ObR expression. Six-week-old rats were fed with a standard rat chow (control) or a 25% FD for 7 weeks until mating and during pregnancy. Also, in a group of control rats, fetuses were injected with leptin on days 19, 20, and 21 of pregnancy. On day 21, we assessed lipidemia, insulinemia, and leptinemia in mothers and fetuses. In the placenta and fetal liver, lipid concentration was assessed by thin layer chromatography (TLC) and the gene expression of lipoprotein lipase (LPL), endothelial lipase, insulin receptor (Insr), leptin, and ObR by RT-PCR. The FD induced hypertriglyceridemia and hyperleptinemia (P<0.01) in mothers and fetuses, an increase in maternal (P<0.05) and fetal weight (P<0.01), overaccumulation of lipids in fetal liver (P<0.01), and enhanced leptin expression in the placenta and fetal liver (P<0.05). Placental expression of IR and LPL was increased (P<0.05), and ObR decreased (P<0.05) in the FD group. Fetal administration of leptin induced the placental and fetal liver downregulation of ObR (P<0.05) and upregulation of LPL expression (P<0.05). The FD led to increased fetal lipid levels, which may result from high maternal lipid availability and fetal leptin effects.
Assuntos
Dieta Hiperlipídica , Ácidos Graxos/farmacologia , Lipídeos/sangue , Lipase Lipoproteica/metabolismo , Placenta/metabolismo , Receptores para Leptina/metabolismo , Animais , Gorduras na Dieta/metabolismo , Gorduras na Dieta/farmacologia , Feminino , Leptina/genética , Leptina/metabolismo , Lipase/genética , Lipase/metabolismo , Lipase Lipoproteica/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Placenta/efeitos dos fármacos , Gravidez , Ratos , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Receptores para Leptina/genéticaRESUMO
OBJECTIVES: Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in placental development and function, although related to the pro-inflammatory environment when produced in excess. Previous studies have identified MMP-2 and MMP-9 overactivities in the placenta from diabetic rats. In this study, we aimed to determine whether diets supplemented with olive and safflower oil, enriched in natural PPAR ligands, are able to regulate MMP-2 and MMP-9 activities in the placenta and serum from diabetic rats. STUDY DESIGN: Diabetes was induced in rat neonates by streptozotocin administration (90mg/kg s.c.). Control and diabetic rats were fed with 6% olive oil- or 6% safflower oil-supplemented diets from days 0.5-13.5 of gestation. MAIN OUTCOME MEASURES: On day 13.5 of gestation, placentas and sera were isolated for further determination of matrix metalloproteinases (MMPs) 2 and 9 activities by zymography. Placental MMP-2 and MMP-9 protein concentration and immunolocalization were also determined. RESULTS: Sera from diabetic pregnant animals showed MMP-2 and MMP-9 overactivities when compared to controls. Serum MMP-9 activity was significantly decreased when the diabetic animals received the olive and safflower oil dietary treatments. Placentas from diabetic rats showed increased MMP-2 and MMP-9 activities and protein concentrations, and both were decreased when diabetic rats received the olive and safflower dietary treatments. CONCLUSIONS: This study demonstrates that both olive and safflower oil-supplemented diets were able to prevent MMPs overactivities in the placenta from diabetic rats, and that these beneficial effects are reflected in rat sera.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Placenta/metabolismo , Óleos de Plantas/uso terapêutico , Gravidez em Diabéticas/dietoterapia , Óleo de Cártamo/uso terapêutico , Animais , Biomarcadores/sangue , Precursores Enzimáticos/metabolismo , Feminino , Ligantes , Metaloproteinase 2 da Matriz/sangue , Metaloproteinase 9 da Matriz/sangue , Azeite de Oliva , Receptores Ativados por Proliferador de Peroxissomo/agonistas , Placenta/imunologia , Placenta/patologia , Gravidez , Proteínas da Gravidez/sangue , Proteínas da Gravidez/metabolismo , Gravidez em Diabéticas/imunologia , Gravidez em Diabéticas/metabolismo , Gravidez em Diabéticas/patologia , Transporte Proteico , Distribuição Aleatória , Ratos , Ratos Wistar , EstreptozocinaRESUMO
Peroxisome proliferator-activated receptors (PPARα, PPARδ and PPARγ) are ligand-activated transcription factors that regulate metabolic, anti-inflammatory and developmental processes. The maternal and fetal metabolic impairments, the intrauterine pro-inflammatory environment and the developmental defects induced by maternal diabetes make PPARs an interesting focus of investigation. Therefore, research has been conducted in experimental models of diabetes throughout gestation. During embryo organogenesis, impaired PPARδ signaling pathways are related to the induction of congenital malformations. In fetuses from diabetic rats, both lipid metabolism and several pro-inflammatory markers are regulated by the activation of PPAR isotypes. In the placenta from diabetic animals, activation of different PPAR isotypes regulates lipid metabolism and anti-inflammatory pathways, whereas in term placentas from diabetic patients PPARγ reduces the production of nitric oxide. Decreased PPARγ and PPARα protein expression are found in term placentas of diabetic animals and diabetic patients. In addition, a deficiency in polyunsaturated fatty acids (PUFAs) and impaired formation of arachidonic acid derivatives that activate PPARs is found in several diabetic intrauterine tissues. PPARs can be activated by both natural and pharmacological activators. Intrauterine activation of PPARs can be achieved by the administration of maternal diets enriched in PUFAs. This review summarizes recent advances highlighting the possible beneficial role of PPAR activation on embryonic and feto-placental development in maternal diabetes.
Assuntos
Diabetes Gestacional/metabolismo , Feto/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/fisiologia , Placenta/metabolismo , Gravidez em Diabéticas/metabolismo , Animais , Diabetes Gestacional/fisiopatologia , Feminino , Feto/embriologia , Feto/fisiopatologia , Humanos , Placenta/embriologia , Placenta/fisiopatologia , Gravidez , Gravidez em Diabéticas/fisiopatologiaRESUMO
Aberrant arachidonic acid and nitric oxide (NO) metabolic pathways are involved in diabetic embryopathy. Previous works have found diminished concentrations of PGE(2) and PGI(2) in embryos from diabetic rats, and that PGI(2) is capable of increasing embryonic PGE(2) concentrations through the activation of the nuclear receptor PPARdelta. PPARdelta activators are lipid molecules such as oleic and linoleic acids, present in high concentrations in olive and safflower oils, respectively. The aim of this study was to analyze the capability of dietary supplementation with either 6% olive or 6% safflower oils to regulate PGE(2), PGI(2) and NO concentrations in embryos and deciduas from control and diabetic rats during early organogenesis. Diabetes was induced by a single injection of streptozotocin (55 mg/kg) 1 week before mating. Animals were fed with the oil-supplemented diets from Days 0.5 to 10.5 of gestation. PGI(2) and PGE(2) were measured by EIA and NO through the evaluation of its stable metabolites nitrates-nitrites in 10.5 day embryos and deciduas. We found that the olive and safflower oil-supplemented treatments highly reduced resorption and malformation rates in diabetic animals, and that they were able to prevent maternal diabetes-induced alterations in embryonic and decidual PGI(2) and PGE(2) concentrations. Moreover, these dietary treatments prevented NO overproduction in embryos and deciduas from diabetic rats. These data indicate that in maternal diabetes both the embryo and the decidua benefit from the olive and safflower oil supplementation probably through mechanisms that involve the rescue of aberrant prostaglandin and NO generation and that prevent developmental damage during early organogenesis.
Assuntos
Ácido Araquidônico/metabolismo , Gorduras na Dieta/administração & dosagem , Suplementos Nutricionais , Doenças Fetais/prevenção & controle , Óxido Nítrico/metabolismo , Óleos de Plantas/administração & dosagem , Óleo de Cártamo/administração & dosagem , Animais , Diabetes Mellitus Experimental/metabolismo , Dinoprostona/metabolismo , Embrião de Mamíferos/metabolismo , Feminino , Masculino , Modelos Biológicos , Azeite de Oliva , Gravidez , Gravidez em Diabéticas , Ratos , Ratos WistarRESUMO
BACKGROUND: Maternal diabetes is associated with morphological placental abnormalities and foeto-placental impairments. These alterations are linked with a dysregulation of the activity of matrix metalloproteinases (MMPs). We investigated the action of 15deoxyDelta(12,14) prostaglandin J(2) (15dPGJ(2)), a natural ligand of the peroxisome proliferator activated receptor (PPAR) gamma, on MMP-2 and MMP-9 activities and tissue inhibitors of matrix metalloproteinases (TIMP) levels in foetuses and placentas from diabetic rats. MATERIALS AND METHODS: Diabetes was induced in rat neonates by a single streptozotocin administration (90 mg kg(-1) s.c.). At 13.5 days of gestation, foetal and placental homogenates were prepared for the determination of PPARgamma levels (western blot) and 15dPGJ(2) concentration (enzyme-immunoassay), whereas the in vitro effect of 15dPGJ(2) (2 microM) was evaluated on placental and foetal MMPs and TIMP activities (zymography and reverse zymography), nitrate/nitrite concentrations (Griess method) and thiobarbituric acid reactive substances (TBARS). RESULTS: PPARgamma was increased while 15dPGJ(2) was decreased in placentas and foetuses from diabetic rats. 15dPGJ(2) additions were able to reduce the high activities of MMP-2 and MMP-9 present in diabetic placental tissues. 15dPGJ(2) additions reduced MMP-2 activity in control and diabetic foetuses. TIMP-3 levels were decreased in diabetic placentas and 15dPGJ(2) was able to enhance them to control values. Nitrates/nitrites and TBARS, metabolites of MMPs activators, were increased in the diabetic placenta and reduced by 15dPGJ(2). CONCLUSIONS: This study demonstrates that 15dPGJ(2) is a potent modulator of the balance between MMP activities and TIMP levels, which is needed in the correct formation and function of the placenta and foetal organs.
Assuntos
Diabetes Mellitus/metabolismo , Feto/efeitos dos fármacos , Metaloproteinases da Matriz/efeitos dos fármacos , PPAR gama/antagonistas & inibidores , Placenta/efeitos dos fármacos , Prostaglandina D2/análogos & derivados , Animais , Diabetes Mellitus/enzimologia , Modelos Animais de Doenças , Feminino , Feto/metabolismo , Gelatinases/metabolismo , Metaloproteinases da Matriz/metabolismo , Óxido Nítrico/metabolismo , PPAR gama/metabolismo , Placenta/metabolismo , Gravidez , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacologia , Ratos , Ratos Wistar , Inibidores Teciduais de Metaloproteinases/efeitos dos fármacos , Inibidores Teciduais de Metaloproteinases/metabolismoRESUMO
Maternal diabetes impairs fetal development and growth. We studied the effects of maternal diets enriched in unsaturated fatty acids capable of activating peroxisome proliferator-activated receptors (PPARs) on the concentrations of 15deoxyDelta12,14PGJ2 (15dPGJ2), lipid mass, and the de novo lipid synthesis in 13.5-day fetuses from control and diabetic rats. Diabetes was induced by neonatal streptozotocin administration (90 mg/kg). Rats were treated with a standard diet supplemented or not with 6% olive oil or 6% safflower oil from days 0.5 to 13.5 of gestation. Fetuses from diabetic rats fed with the standard diet showed reduced 15dPGJ2 concentrations, whereas maternal treatments with olive and safflower oils increased 15dPGJ2 concentrations. Fetuses from diabetic rats showed increased concentrations of phospholipids and increased synthesis of triglycerides, phospholipids, cholesterol and free fatty acids. Diabetic rat treatments with olive and safflower oils reduced phospholipids, cholesterol, and free fatty acid concentrations and the de novo lipid synthesis in the fetuses. These effects were different from those observed in fetuses from control rats, and seem not to involve PPARgamma activation. In conclusion, olive oil- and safflower oil-supplemented diets provide beneficial effects in maternal diabetes, as they prevent fetal impairments in 15dPGJ2 concentrations, lipid synthesis and lipid accumulation.
Assuntos
Feto/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Receptores Ativados por Proliferador de Peroxissomo/agonistas , Animais , Animais Recém-Nascidos , Colesterol/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/farmacologia , Ácidos Graxos não Esterificados/metabolismo , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Insaturados/farmacologia , Feminino , Feto/metabolismo , Masculino , Azeite de Oliva , Óleos de Plantas/administração & dosagem , Óleos de Plantas/farmacologia , Gravidez , Ratos , Óleo de Cártamo/administração & dosagem , Óleo de Cártamo/farmacologia , Estreptozocina , Triglicerídeos/metabolismoRESUMO
Maternal diabetes promotes an overaccumulation of lipids in the feto-placental unit and impairs feto-placental development and growth. Here, we investigated the role played by the nuclear receptor peroxisome proliferator-activated receptor (PPAR)alpha in lipid metabolism in fetuses and placentas from control and neonatal streptozotocin-induced diabetic rats. Placentas and fetuses were studied on day 13.5 of gestation. The concentrations of PPARalpha (by Western blot) and its endogenous agonist leukotriene B(4) (LTB(4)) (by enzyme immunoassay) were analysed. Placental explants and fetuses were cultured with LTB(4) or clofibrate, and then lipid metabolism analysed (concentrations and synthesis from (14)C-acetate of triglycerides, phospholipids, cholesterol and cholesteryl esters; release of glycerol and free fatty acids (FFAs)). We found that maternal diabetes led to increases in placental concentrations of triglycerides and cholesteryl esters, and fetal concentrations of phospholipids. PPARalpha agonists downregulated fetal and placental lipid concentrations in control and diabetic rats. The synthesis of lipids was reduced in the diabetic placenta but increased in fetuses from diabetic animals. PPARalpha agonists reduced the synthesis of lipids in control placenta and in the fetuses from control and diabetic rats. Glycerol and FFA release was enhanced in the diabetic placenta and in control placenta cultured with PPARalpha agonists. Maternal diabetes led to reductions in fetal and placental LTB(4) concentrations and to increases in placental PPARalpha concentrations. Overall, these data support a novel role of PPARalpha as a regulator of lipid metabolism in the feto-placental unit, relevant in maternal diabetes where fetal and placental PPARalpha, LTB(4) and lipid concentrations are altered.
Assuntos
Diabetes Gestacional/metabolismo , Feto/metabolismo , Metabolismo dos Lipídeos , PPAR alfa/metabolismo , Placenta/metabolismo , Animais , Ácidos Graxos não Esterificados/análise , Feminino , Glicerol/análise , Leucotrieno B4/análise , Leucotrieno B4/metabolismo , Lipídeos/análise , Lipídeos/biossíntese , PPAR alfa/análise , Gravidez , Ratos , Ratos WistarRESUMO
Matrix metalloproteinases (MMPs) play an important role in tissue remodeling that accompanies the rapid growth, differentiation, and structural changes of the placenta and several fetal organs. In the present study, we investigated whether the diabetic maternal environment may alter the regulatory homeostasis exerted by nitric oxide (NO) on MMPs activity in the feto-placental unit from rats at midgestation. We found that NADPH-diaphorase activity, which reflects the distribution and activity of NO synthases (NOS), was increased in both placenta and fetuses from diabetic rats when compared with controls. In addition, while a NO donor enhanced MMP2 and MMP9 activities, a NOS inhibitor reduced these activities in the maternal side of the placenta from control rats. This regulatory effect of NO was only observed on MMP9 in the diabetic group. On the other hand, the NO donor did not modify MMP2 and MMP9 activities, while the NOS inhibitor reduced MMP9 activity in the fetal side of both control and diabetic placentas. In the fetuses, MMP2 was enhanced by the NO donor and reduced by the NO inhibitor in both fetuses from control and diabetic rats. Overall, this study demonstrates that NO is able to modulate the activation of MMPs in the feto-placental unit, and provides supportive evidence that increased NOS activity leads to NO overproduction in the feto-placental unit from diabetic rats, an alteration closely related to the observed MMPs dysregulation that may have profound implications in the formation and function of the placenta and the fetal organs.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Feto/enzimologia , Metaloproteinases da Matriz/metabolismo , Óxido Nítrico/fisiologia , Placenta/enzimologia , Animais , Western Blotting/métodos , Eletroforese em Gel de Poliacrilamida , Feminino , Feto/efeitos dos fármacos , Metaloproteinase 2 da Matriz/análise , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/análise , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinases da Matriz/análise , NG-Nitroarginina Metil Éster/farmacologia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/análise , Óxido Nítrico Sintase Tipo III/análise , Nitroprussiato/farmacologia , Placenta/efeitos dos fármacos , Gravidez , Ratos , Ratos WistarRESUMO
Maternal diabetes significantly increases the risk of congenital malformations, and the mechanisms involved are not yet clarified. This study was designed to address peroxisome proliferator-activated receptor delta (PPARdelta) involvement in diabetic embryopathy. We investigated the concentrations of PPARdelta and its endogenous agonist prostaglandin (PG)I(2), as well as the effect of PPARdelta activation on lipid metabolism and PGE(2) concentrations in embryos from control and streptozotocin-induced diabetic rats during early organogenesis. Embryos from diabetic rats showed decreased concentrations of PPARdelta and its endogenous agonist PGI(2) when compared with controls. In embryos from control rats, the addition of the PPARdelta activators (cPGI(2) and PGA(1)) increased embryonic phospholipid levels and de novo phospholipid synthesis studied using (14)C-acetate as a tracer. PGE(2) formed from arachidonate released from phospholipid stores was also up-regulated by PPARdelta activators. In embryos from diabetic rats, reduced phospholipid synthesis and PGE(2) content were observed, and clearly up-regulated by cPGI(2) additions to values similar to those found in control embryos. These data suggest that PPARdelta may play an important role in lipid metabolic and signalling pathways during embryo organogenesis, developmental pathways that are altered in embryos from diabetic rats, possibly as a result of a reduction in levels of PPARdelta and its endogenous activator PGI(2).