RESUMEN

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.

Asunto(s)

Diabetes Gestacional/metabolismo , Leucotrieno B4/metabolismo , Metabolismo de los Lípidos , Lípidos/química , Pulmón/metabolismo , PPAR alfa/metabolismo , PPAR gamma/metabolismo , Prostaglandina D2/análogos & derivados , Animales , Diabetes Gestacional/genética , Femenino , Feto/embriología , Feto/metabolismo , Ligandos , Pulmón/química , Pulmón/embriología , Masculino , Aceite de Oliva , PPAR alfa/genética , PPAR gamma/genética , Aceites de Plantas/metabolismo , Embarazo , Prostaglandina D2/metabolismo , Ratas , Ratas Wistar , Aceite de Cártamo/metabolismo

RESUMEN

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.

Asunto(s)

Dieta Alta en Grasa , Ácidos Grasos/farmacología , Lípidos/sangre , Lipoproteína Lipasa/metabolismo , Placenta/metabolismo , Receptores de Leptina/metabolismo , Animales , Grasas de la Dieta/metabolismo , Grasas de la Dieta/farmacología , Femenino , Leptina/genética , Leptina/metabolismo , Lipasa/genética , Lipasa/metabolismo , Lipoproteína Lipasa/genética , Hígado/efectos de los fármacos , Hígado/metabolismo , Placenta/efectos de los fármacos , Embarazo , Ratas , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Receptores de Leptina/genética

RESUMEN

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.

Asunto(s)

Antiinflamatorios no Esteroideos/uso terapéutico , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Placenta/metabolismo , Aceites de Plantas/uso terapéutico , Embarazo en Diabéticas/dietoterapia , Aceite de Cártamo/uso terapéutico , Animales , Biomarcadores/sangre , Precursores Enzimáticos/metabolismo , Femenino , Ligandos , Metaloproteinasa 2 de la Matriz/sangre , Metaloproteinasa 9 de la Matriz/sangre , Aceite de Oliva , Receptores Activados del Proliferador del Peroxisoma/agonistas , Placenta/inmunología , Placenta/patología , Embarazo , Proteínas Gestacionales/sangre , Proteínas Gestacionales/metabolismo , Embarazo en Diabéticas/inmunología , Embarazo en Diabéticas/metabolismo , Embarazo en Diabéticas/patología , Transporte de Proteínas , Distribución Aleatoria , Ratas , Ratas Wistar , Estreptozocina

RESUMEN

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.

Asunto(s)

Diabetes Gestacional/metabolismo , Feto/metabolismo , Receptores Activados del Proliferador del Peroxisoma/fisiología , Placenta/metabolismo , Embarazo en Diabéticas/metabolismo , Animales , Diabetes Gestacional/fisiopatología , Femenino , Feto/embriología , Feto/fisiopatología , Humanos , Placenta/embriología , Placenta/fisiopatología , Embarazo , Embarazo en Diabéticas/fisiopatología

RESUMEN

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.

Asunto(s)

Ácido Araquidónico/metabolismo , Grasas de la Dieta/administración & dosificación , Suplementos Dietéticos , Enfermedades Fetales/prevención & control , Óxido Nítrico/metabolismo , Aceites de Plantas/administración & dosificación , Aceite de Cártamo/administración & dosificación , Animales , Diabetes Mellitus Experimental/metabolismo , Dinoprostona/metabolismo , Embrión de Mamíferos/metabolismo , Femenino , Masculino , Modelos Biológicos , Aceite de Oliva , Embarazo , Embarazo en Diabéticas , Ratas , Ratas Wistar

RESUMEN

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.

Asunto(s)

Diabetes Mellitus/metabolismo , Feto/efectos de los fármacos , Metaloproteinasas de la Matriz/efectos de los fármacos , PPAR gamma/antagonistas & inhibidores , Placenta/efectos de los fármacos , Prostaglandina D2/análogos & derivados , Animales , Diabetes Mellitus/enzimología , Modelos Animales de Enfermedad , Femenino , Feto/metabolismo , Gelatinasas/metabolismo , Metaloproteinasas de la Matriz/metabolismo , Óxido Nítrico/metabolismo , PPAR gamma/metabolismo , Placenta/metabolismo , Embarazo , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacología , Ratas , Ratas Wistar , Inhibidores Tisulares de Metaloproteinasas/efectos de los fármacos , Inhibidores Tisulares de Metaloproteinasas/metabolismo

RESUMEN

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.

Asunto(s)

Feto/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , Receptores Activados del Proliferador del Peroxisoma/agonistas , Animales , Animales Recién Nacidos , Colesterol/metabolismo , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/metabolismo , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/farmacología , Ácidos Grasos no Esterificados/metabolismo , Ácidos Grasos Insaturados/administración & dosificación , Ácidos Grasos Insaturados/farmacología , Femenino , Feto/metabolismo , Masculino , Aceite de Oliva , Aceites de Plantas/administración & dosificación , Aceites de Plantas/farmacología , Embarazo , Ratas , Aceite de Cártamo/administración & dosificación , Aceite de Cártamo/farmacología , Estreptozocina , Triglicéridos/metabolismo

RESUMEN

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.

Asunto(s)

Diabetes Gestacional/metabolismo , Feto/metabolismo , Metabolismo de los Lípidos , PPAR alfa/metabolismo , Placenta/metabolismo , Animales , Ácidos Grasos no Esterificados/análisis , Femenino , Glicerol/análisis , Leucotrieno B4/análisis , Leucotrieno B4/metabolismo , Lípidos/análisis , Lípidos/biosíntesis , PPAR alfa/análisis , Embarazo , Ratas , Ratas Wistar

RESUMEN

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.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Feto/enzimología , Metaloproteinasas de la Matriz/metabolismo , Óxido Nítrico/fisiología , Placenta/enzimología , Animales , Western Blotting/métodos , Electroforesis en Gel de Poliacrilamida , Femenino , Feto/efectos de los fármacos , Metaloproteinasa 2 de la Matriz/análisis , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/análisis , Metaloproteinasa 9 de la Matriz/metabolismo , Metaloproteinasas de la Matriz/análisis , NG-Nitroarginina Metil Éster/farmacología , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II/análisis , Óxido Nítrico Sintasa de Tipo III/análisis , Nitroprusiato/farmacología , Placenta/efectos de los fármacos , Embarazo , Ratas , Ratas Wistar

RESUMEN

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).

Asunto(s)

Diabetes Mellitus Experimental/embriología , Epoprostenol/metabolismo , Enfermedades Fetales/metabolismo , Metabolismo de los Lípidos , Organogénesis , PPAR delta/metabolismo , Preñez , Animales , Dinoprostona/análisis , Técnicas de Cultivo de Embriones , Embrión de Mamíferos/anatomía & histología , Embrión de Mamíferos/metabolismo , Epoprostenol/farmacología , Femenino , Desarrollo Fetal/efectos de los fármacos , Enfermedades Fetales/inducido químicamente , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , PPAR delta/fisiología , Embarazo , Embarazo en Diabéticas , Ratas , Ratas Wistar , Transducción de Señal , Estreptozocina

RESUMEN

Maternal diabetes significantly increases the risk of congenital malformation, a syndrome known as diabetic embryopathy. Nitric oxide (NO), implicated in embryogenesis, has been found elevated in embryos from diabetic rats during organogenesis. The developmental signaling molecules endothelin-1 (ET-1) and 15-deoxy delta(12,14)prostaglandin J2 (15dPGJ2) downregulate embryonic NO levels. In the presence of NO and superoxide, formation of the potent oxidant peroxynitrite may occur. Therefore, we investigated peroxynitrite-induced damage, ET-1 and 15dPGJ2 concentrations, and the capability of ET-1, 15dPGJ2 and prostaglandin E2 (PGE2) to regulate NO production in embryos from severely diabetic rats (streptozotocin-induced before pregnancy). We found intense nitrotyrosine immunostaining (an index of peroxynitrite-induced damage) in neural folds, neural tube and developing heart of embryos from diabetic rats (P < 0.001 vs controls). We also found reduced ET-1 (P < 0.001) and 15dPGJ2 (P < 0.001) concentrations in embryos from diabetic rats when compared with controls. In addition, the inhibitory effect of ET-1, 15dPGJ2 and PGE2 on NO production found in control embryos was not observed in embryos from severely diabetic rats. In conclusion, both the demonstrated peroxynitrite-induced damage and the altered levels and function of multiple signaling molecules involved in the regulation of NO production provide supportive evidence of nitrosative stress in diabetic embryopathy.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Embrión de Mamíferos/metabolismo , Óxido Nítrico/metabolismo , Organogénesis/fisiología , Embarazo en Diabéticas/metabolismo , Tirosina/análogos & derivados , Animales , Embrión de Mamíferos/química , Endotelina-1/análisis , Femenino , Inmunohistoquímica/métodos , Nitratos/análisis , Nitritos/análisis , Embarazo , Prostaglandina D2/análogos & derivados , Prostaglandina D2/análisis , Ratas , Ratas Wistar , Tirosina/análisis

RESUMEN

15-Deoxy-Delta(12,14)-prostaglandin J2 (15dPGJ2) is a peroxisome proliferator-activated receptor (3) (PPAR(3)) ligand that regulates lipid homeostasis and has anti-inflammatory properties in many cell types. We postulated that 15dPGJ2 may regulate lipid homeostasis and nitric oxide (NO) levels in term placental tissues and that alterations in these pathways may be involved in diabetes-induced placental derangements. In the present study, we observed that, in term placental tissues from streptozotocin-induced diabetic rats, 15dPGJ2 concentrations were decreased (83%) and immunostaining for nitrotyrosine, indicating peroxynitrite-induced damage, was increased. In the presence of 15dPGJ2, concentrations of nitrates/nitrites (an index of NO production) were diminished (40%) in both control and diabetic rats, an effect that seems to be both dependent on and independent of PPAR(3) activation. Exogenous 15dPGJ2 did not modify lipid mass, but decreased the incorporation of (14)C-acetate into triacylglycerol (35%), cholesteryl ester (55%) and phospholipid (32%) in placenta from control rats, an effect that appears to be dependent on PPAR(3) activation. In contrast, the addition of 15dPGJ2 did not alter de novo lipid synthesis in diabetic rat placenta, which showed decreased levels of PPAR(3). We conclude that 15dPGJ2 modulates placental lipid metabolism and NO production. The concentration and function of 15dPGJ2 and concentrations of PPAR(3) were altered in placentas from diabetic rats, anomalies probably involved in diabetes-induced placental dysfunction.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , PPAR gamma/metabolismo , Placenta/metabolismo , Prostaglandina D2/análogos & derivados , Acetatos/metabolismo , Animales , Glucemia/metabolismo , Estudios de Casos y Controles , Diabetes Mellitus Experimental/tratamiento farmacológico , Femenino , Edad Gestacional , Nitratos/metabolismo , Nitritos/metabolismo , PPAR gamma/agonistas , Ácido Peroxinitroso/farmacología , Placenta/efectos de los fármacos , Embarazo , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacología , Ratas , Ratas Wistar , Estreptozocina/toxicidad , Tirosina/análogos & derivados , Tirosina/farmacología

RESUMEN

Matrix metalloproteinases (MMPs) are involved in placental remodelling throughout pregnancy. Diabetes mellitus induces alterations in tissue production of NO, a regulator of MMPs activity. The present work evaluates placental and fetal MMPs and NO levels during midpregnancy in neonatal streptozotocin-induced diabetic rats. MMP-2 and MMP-9 immunolabelling was increased both in the labyrinth zone (p<0.001) and in the giant trophoblast cells of the junctional zone (p<0.001) from diabetic placenta, when compared with controls. Also MMP-2 (p<0.01) and MMP-9 (p<0.005) activities were increased in both maternal and fetal sides of diabetic placenta when related to controls. In both sides of the diabetic placenta, nitrate/nitrite concentrations (which indicate NO production) were higher than in controls (p<0.05). An intense immunostaining for nitrotyrosine, indicating peroxynitrite-induced damage, was found in both labyrinth (p<0.001) and junctional zones (p<0.001) of diabetic placenta. Enhanced MMP-2 activity (p<0.05) and NO production were also higher in the fetuses from diabetic rats when compared to controls (p<0.005). These findings demonstrate alterations in MMPs and NO in the feto-placental unit of diabetic rats, anomalies that are likely to be involved in the developmental alterations induced by maternal diabetes.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Placenta/metabolismo , Animales , Diabetes Mellitus Experimental/enzimología , Femenino , Edad Gestacional , Inmunohistoquímica , Nitratos/metabolismo , Nitritos/metabolismo , Placenta/química , Placenta/enzimología , Embarazo , Ratas , Ratas Wistar , Tirosina/análogos & derivados , Tirosina/análisis , Tirosina/metabolismo

RESUMEN

Diabetes induces alterations which condition placental remodelling. The levels of nitric oxide (NO) (a modulator of placental invasiveness, differentiation and proliferation) were higher in term placental explants from diabetic patients when compared to controls. Peroxisome proliferator-activated receptor gamma (PPARgamma) activation by its endogenous ligand 15-deoxy Delta(12,14)prostaglandin J(2) (15dPGJ(2)), is a differentiating factor of adipocytes and other cell types, such as trophoblasts. 15dPGJ(2) is also able to down-regulate NO production in different cell types. Our study evaluated the levels of 15dPGJ(2) and PPARgamma and the influence of PPARgamma activation by 15dPGJ(2) on the production of NO, in term placental tissues from control, pre-gestational and gestational diabetic patients. Our results showed that 15dPGJ(2) was present in human term placenta, and that its levels were diminished in gestational (P<0.05) and pre-gestational (P<0.002) diabetic women when compared to controls. Exogenous 15dPGJ(2) addition (2 x 10(-6) mol/l) down-regulated NO production in placenta from control (P<0.001) and pre-gestational diabetic (P<0.01) patients, but failed to do so in gestational diabetic women, whose placental PPARgamma expression was diminished in comparison to controls (P<0.001). As the exogenous activation of PPARgamma prevented NO overproduction in placenta from pre-gestational diabetic women, it may have the potential to improve fetal outcome in this pathology.

Asunto(s)

Diabetes Mellitus Tipo 1/metabolismo , Diabetes Gestacional/metabolismo , Factores Inmunológicos/metabolismo , Óxido Nítrico/biosíntesis , PPAR gamma/metabolismo , Placenta/metabolismo , Embarazo en Diabéticas/metabolismo , Prostaglandina D2/análogos & derivados , Femenino , Humanos , Nitratos/metabolismo , Nitritos/metabolismo , Embarazo , Prostaglandina D2/metabolismo

RESUMEN

Endothelin-1 (ET-1), nitric oxide (NO) and prostaglandin E(2) (PGE(2)) are regulators of feto-placental hemodynamics. In this study we explore the inter-regulatory pathways that modulate the levels of these vasoactive agents in control and neonatal streptozotocin-induced (n-stz) diabetic rat placenta. ET-1 levels are increased in diabetic placenta when compared to controls (P<0.001), and are strongly reduced by an NO synthase inhibitor (P<0.001). PGE(2) production is increased in diabetic placenta when compared to controls (P<0.01), but these levels are not modulated by ET-1. NO levels, similar in control and in diabetic placenta, are not influenced by PGE(2), but they are negatively modulated by ET-1 in both control (P<0.05) and diabetic (P<0.01) placenta. We conclude that rat placental ET-1 inhibits NO levels but does not modify PGE(2) concentrations. The elevated levels of ET-1 and PGE(2) in diabetic placenta, potent vasoconstrictors of placental vasculature, are probably related to the induction of placental insufficiency and fetal hypoxia in this pathology.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Dinoprostona/metabolismo , Endotelina-1/metabolismo , Óxido Nítrico/biosíntesis , Placenta/metabolismo , Animales , Animales Recién Nacidos , Diabetes Mellitus Experimental/fisiopatología , Femenino , Hipoxia Fetal/etiología , Hipoxia Fetal/fisiopatología , Placenta/irrigación sanguínea , Insuficiencia Placentaria/etiología , Insuficiencia Placentaria/fisiopatología , Embarazo , Ratas , Ratas Wistar , Vasoconstricción/fisiología

RESUMEN

The concentration of 15-deoxy Delta(12,14)PGJ(2) (15dPGJ(2)) and its effects on nitric oxide generation and neutral lipid in embryos from control and neonatal streptozotocin-induced (n-stz) diabetic rats during organogenesis were investigated. 15dPGJ(2) is produced in embryos during organogenesis, and its production is lower in embryos of n-stz diabetic rats than in embryos from control rats. Nitrate and nitrite concentrations were higher in embryos from n-stz diabetic rats and were reduced in the presence of 15dPGJ(2) both in embryos from control and diabetic rats. Thus, decreased 15dPGJ(2) concentrations in embryos from n-stz diabetic rats may be related to the high nitric oxide concentrations found in those embryos. Exogenous 15dPGJ(2) decreased cholesterol and cholesteryl ester concentrations in embryos from control and n-stz diabetic rats, and reduced triacylglycerol concentrations in control embryos. Incorporation of [(14)C]acetate into lipids showed decreased de novo synthesis of cholesteryl ester and triacylglycerides in embryos from n-stz diabetic rats compared with controls. Exogenous 15dPGJ(2) reduced the incorporation of [(14)C]acetate into triacylglycerides, cholesterol and cholesteryl ester in embryos from both control and n-stz diabetic rats. 15dPGJ(2) is present in embryos during organogenesis, and reduces embryonic nitric oxide production and lipid synthesis. The lower 15dPGJ(2) concentration in embryos from n-stz diabetic rats may result in developmental alterations in this diabetic model.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Feto/metabolismo , Metabolismo de los Lípidos , Óxido Nítrico/metabolismo , Embarazo en Diabéticas/metabolismo , Prostaglandina D2/farmacología , Acetatos/metabolismo , Análisis de Varianza , Animales , Colesterol/metabolismo , Ésteres del Colesterol/metabolismo , Técnicas de Cultivo , Femenino , Feto/química , Feto/efectos de los fármacos , Lípidos/análisis , Lipoproteínas/metabolismo , Nitratos/análisis , Nitritos/análisis , Organogénesis/fisiología , Embarazo , Prostaglandina D2/análogos & derivados , Prostaglandina D2/análisis , Ratas , Ratas Wistar , Triglicéridos/metabolismo

RESUMEN

In this work we assessed NO levels in the control and diabetic embryo during early organogenesis, and the ability of NO and SOD to modify embryonic PGE2 levels. Rats were made diabetic by steptozotocin (60 mg/kg) before mating. Diabetic embryos (day 10 of gestation) show increased nitrate/nitrite levels and enhanced NOS activity. The diabetic embryos release to the incubation medium increased amounts of PGE2 and have diminished PGE2 content. In the control embryo NO modulates PGE2 levels, but this modulatory pathway is not observed in the diabetic embryos. The diminished PGE2 content and the enhanced PGE2 release is prevented by SOD additions, both in the diabetic embryos and in control embryos cultured in the presence of diabetic serum (24 h culture, explantation day 9). The present results show that SOD additions prevent the abnormalities in the accumulation, production and release of PGE2 in diabetic embryos, probably related to the decrease in malformations.

Asunto(s)

Diabetes Mellitus Experimental/embriología , Dinoprostona/biosíntesis , Embrión de Mamíferos/metabolismo , Óxido Nítrico/metabolismo , Superóxido Dismutasa/metabolismo , Animales , Técnicas de Cultivo , Femenino , Masculino , Ratas , Ratas Wistar , Factores de Tiempo