Review on intrauterine programming: Consequences in rodent models of mild diabetes and mild fat overfeeding are not mild.

An adverse intrauterine programming occurs in diabetes and obesity as the consequence of an adverse maternal environment that affects the appropriate fetoplacental development and growth. Experimental models of diabetes and fat overfeeding have provided relevant tools to address putative mechanisms of the adverse intrauterine programming. The current knowledge far extends from the original thoughts of the resulting intrauterine programming of metabolic and cardiovascular diseases to a full range of alterations that affect multiple tissues, organs, and systems that will compromise the long-life health of the offspring. This review examines the postnatal effects of rodent models of mild diabetes and fat overfeeding, identifying the multiple organ derangements in the offspring resulting from mild maternal adverse conditions. In addition, the comparison of experimental models of severe diabetes and fat overfeeding and the crucial role of the placenta are discussed, providing an update of the actual scenario of the putative mechanisms and adverse consequences of maternal metabolic derangements.

IFPA meeting 2015 workshop report III: nanomedicine applications and exosome biology, xenobiotics and endocrine disruptors and pregnancy, and lipid.

Workshops are an important part of the IFPA annual meeting, as they allow for discussion of specialized topics. At the IFPA meeting 2015 there were twelve themed workshops, three of which are summarized in this report. These workshops were related to various aspects of placental biology but collectively covered areas of pregnancy pathologies and placental metabolism: 1) nanomedicine applications and exosome biology; 2) xenobiotics and endocrine disruptors and pregnancy; 3) lipid mediators and placental function.

Peroxisome proliferator-activated receptor ligands regulate lipid content, metabolism, and composition in fetal lungs of diabetic rats.

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.

Saturated fat-rich diet increases fetal lipids and modulates LPL and leptin receptor expression in rat placentas.

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.

Intrauterine effects of impaired lipid homeostasis in pregnancy diseases.

Lipids are crucial structural and bioactive components that sustain embryo, fetal and placental development and growth. Intrauterine development can be disturbed by several diseases that impair maternal lipid homeostasis and lead to abnormal lipid concentrations in the fetal circulation. Deficiency in essential fatty acids can lead to congenital malformations and visual and cognitive problems in the newborn. Either deficient mother-to-fetus lipid transfer or abnormal maternal- fetal lipid metabolism can cause fetal growth restriction. On the other hand, excessive mother-to-fetus fatty acid transfer can induce fetal overgrowth and lipid overacummulation in different fetal organs and tissues. The placenta plays a fundamental role in the transfer of lipid moieties to the fetal compartment and is affected by maternal diseases associated with impaired lipid homeostasis. Postnatal consequences may be evident in the neonatal period or later in life. Indeed, both defects and excess of different lipid species can lead to the intrauterine programming of metabolic and cardiovascular diseases in the offspring. This review summarizes the lipid impairments induced by different pathologies, including placental insufficiency, malnutrition, obesity and diabetes, and their consequent developmental defects.

Folic acid and safflower oil supplementation interacts and protects embryos from maternal diabetes-induced damage.

Maternal diabetes increases the risk of embryo malformations. Folic acid and safflower oil supplementations have been shown to reduce embryo malformations in experimental models of diabetes. In this study we here tested whether folic acid and safflower oil supplementations interact to prevent embryo malformations in diabetic rats, and analyzed whether they act through the regulation of matrix metalloproteinases (MMPs), their endogenous inhibitors (TIMPs), and nitric oxide (NO) and reactive oxygen species production. Diabetes was induced by streptozotocin administration prior to mating. From Day 0.5 of pregnancy, rats did or did not receive folic acid (15 mg/kg) and/or a 6% safflower oil-supplemented diet. Embryos and decidua were explanted on Day 10.5 of gestation for further analysis of embryo resorptions and malformations, MMP-2 and MMP-9 activities, TIMP-1 and TIMP-2 levels, NO production and lipid peroxidation. Maternal diabetes induced resorptions and malformations that were prevented by folic acid and safflower oil supplementation. MMP-2 and MMP-9 activities were increased in embryos and decidua from diabetic rats and decreased with safflower oil and folic acid supplementations. In diabetic animals, the embryonic and decidual TIMPs were increased mainly with safflower oil supplementation in decidua and with folic acid in embryos. NO overproduction was decreased in decidua from diabetic rats treated with folic acid alone and in combination with safflower oil. These treatments also prevented increases in embryonic and decidual lipid peroxidation. In conclusion, folic acid and safflower oil supplementations interact and protect the embryos from diabetes-induced damage through several pathways related to a decrease in pro-inflammatory mediators.

Dietary treatments enriched in olive and safflower oils regulate seric and placental matrix metalloproteinases in maternal diabetes.

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.

Review: Effects of PPAR activation in the placenta and the fetus: implications in maternal diabetes.

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.

IFPA Meeting 2010 Workshops Report II: Placental pathology; trophoblast invasion; fetal sex; parasites and the placenta; decidua and embryonic or fetal loss; trophoblast differentiation and syncytialisation.

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications.

Safflower and olive oil dietary treatments rescue aberrant embryonic arachidonic acid and nitric oxide metabolism and prevent diabetic embryopathy in rats.

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.

MMP/ TIMP balance is modulated in vitro by 15dPGJ(2) in fetuses and placentas from diabetic rats.

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.

The effects of maternal dietary treatments with natural PPAR ligands on lipid metabolism in fetuses from control and diabetic rats.

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.

Peroxisome proliferator-activated receptor alpha activation regulates lipid metabolism in the feto-placental unit from diabetic rats.

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.

The role of nitric oxide on matrix metalloproteinase 2 (MMP2) and MMP9 in placenta and fetus from diabetic rats.

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.

PPARdelta and its activator PGI2 are reduced in diabetic embryopathy: involvement of PPARdelta activation in lipid metabolic and signalling pathways in rat embryo early organogenesis.

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).

Diabetic pregnancies: the challenge of developing in a pro-inflammatory environment.

The maternal diabetic environment alters the embryo and the feto-placental development. The results of these alterations are: increased embryo resorption and malformation rates, placental dysfunction, fetal alterations that lead to increased neonatal morbidity and mortality rates, and also diseases that will be evident later in the adult life of the newborn. The etiology of these many maternal diabetes-induced complications are not yet understood in full. In this review the role of maternal diabetes as an inductor of a pro-inflammatory environment that impairs embryo and placental development is discussed. An overproduction of pro-inflammatory agents is found in the uterus during implantation and the developing embryo and placenta from experimental models of diabetes, as well as in placenta from diabetic women. In these tissues there are increases in reactive oxygen species, pro-inflammatory cytokines and prostaglandins, nitric oxide and peroxynitrites. These pro-inflammatory agents lead to the intrauterine activation of matrix metalloproteinases, proteases involved in remodeling the extracellular matrix during implantation and feto-placental development. Many of these pro-inflammatory agents have overlapping mechanisms of action and cross regulatory pathways that propagate the inflammatory processes. Antioxidants, PPARgamma activators, and NF-kappaB inhibitors are able to reduce the concentrations of these agents in intrauterine gestational tissues. This article reviews the current understanding of maternal diabetes-induced changes in pro-inflammatory and anti-inflammatory pathways that affect the embryo and placental development in maternal diabetes, and stresses the need of a strict maternal control of the pathology to prevent deleterious consequences in the offspring.

Peroxynitrites and impaired modulation of nitric oxide concentrations in embryos from diabetic rats during early organogenesis.

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.

15-Deoxy-Delta12,14-prostaglandin J2 and peroxisome proliferator-activated receptor gamma (PPARgamma) levels in term placental tissues from control and diabetic rats: modulatory effects of a PPARgamma agonist on nitridergic and lipid placental metabolism.

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.

Increased matrix metalloproteinases 2 and 9 in placenta of diabetic rats at midgestation.

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.

The role of alterations in arachidonic acid metabolism and nitric oxide homeostasis in rat models of diabetes during early pregnancy.

The diabetic pathology induces reproductive abnormalities that enhance spontaneous abortion, congenital anomalies and neonatal morbidity/mortality rates, abnormalities that begin with an altered female gamete. In this review we focus on the damage induced by maternal hyperglycemia during ovulation, early embryo development, implantation and embryo organogenesis in experimental rat models of diabetes. Hyperglycemia can induce cellular damage by enhancing the production of reactive oxygen species (ROS), by altering arachidonic acid metabolism (thus leading to altered production of prostaglandins such us PGE(2)and 15deoxydelta(12-14)PGJ(2), involved in signalling and developmental pathways), and by enhancing the generation of nitric oxide (a mediator of many cell functions including apoptotic cell death). In maternal diabetes all of these abnormalities are present from the oocyte stage, during embryonic implantation, and during embryo organogenesis. The involvement of these alterations in embryo loss and congenital malformations due to diabetes and the cross-talk among these metabolic pathways are discussed. As maternal hyperglycemia induces damage from the oocyte stage and throughout embryo development the data reviewed suggests the need of strict preconceptional metabolic control. The importance of the molecules involved in hyperglycemia-induced damage as future pharmacological targets for intervention is discussed.