Consumption of the Artificial Sweetener Acesulfame Potassium throughout Pregnancy Induces Glucose Intolerance and Adipose Tissue Dysfunction in Mice.

BACKGROUND: Sugar-sweetened beverage consumption is associated with metabolic dysfunction. Artificially sweetened beverages (ASBs) are often promoted as an alternative. However, evidence for the safety of ASB consumption during pregnancy is lacking. OBJECTIVES: The effects of sugar-sweetened beverage and ASB consumption during pregnancy in mice were examined, and we hypothesized that both sugar-sweetened beverages and ASBs would impair maternal metabolic function. METHODS: Pregnant female C57BL/6J mice received control drinking water (CD), high-fructose corn syrup (Fr; 20% kcal intake; 335 mM), or the artificial sweetener acesulfame potassium (AS; 12.5 mM) in their drinking water, from gestational day (GD) 0.5 (n = 8/group). Body weights and food and water intakes were assessed every second day, an oral-glucose-tolerance test (OGTT) was performed at GD 16.5, and mice were culled at GD 18.5. RT-PCR was carried out on adipose tissue, liver, and gut. Adipose tissue morphology was assessed using histological methods. In a separate cohort of animals, pregnancy length was assessed. Repeated-measures ANOVA was performed for the OGTT and weight gain data. All other data were analyzed by 1-way ANOVA. RESULTS: Fr and AS significantly impaired glucose tolerance, as demonstrated by OGTT (21% and 24% increase in AUC, respectively; P = 0.0006). Fr and AS reduced expression of insulin receptor (39.5% and 33% reduction, respectively; P = 0.02) and peroxisome proliferator-activated receptor γ (45.2% and 47%, respectively; P = 0.039), whereas Fr alone reduced expression of protein kinase B (36.9% reduction; P = 0.048) and resulted in an increase in adipocyte size and leptin concentrations (40% increase; P = 0.03). AS, but not Fr, reduced male fetal weight (16.5% reduction; P = 0.04) and female fetal fasting blood glucose concentration at cull (20% reduction; P = 0.02) compared with CD. AS significantly reduced the length of pregnancy compared with the CD and Fr groups (1.25 d shorter; P = 0.02). CONCLUSIONS: Fr and AS consumption were associated with maternal metabolic dysfunction in mice. AS was also associated with reduced fetal growth and fetal hypoglycemia. Therefore, ASBs may not be a beneficial alternative to sugar-sweetened beverages during pregnancy.

Blunted Cardiac AMPK Response is Associated with Susceptibility to Ischemia/Reperfusion in Male Offspring of Gestational Diabetic Rats.

BACKGROUND/AIMS: Gestational diabetes mellitus (GDM) is closely associated with early perinatal complications and long-term health problems, such as cardiovascular disease, in offspring. AMP-activated protein kinase (AMPK) is cardioprotective, particularly in the treatment of ischemia/reperfusion (I/R). However, whether GDM programs offspring susceptibility to cardiac I/R and the involvement of AMPK remain unclear. METHODS: Streptozotocin was administered to rats during mid pregnancy; the postpartum maternal metabolome was assessed by chromatography-mass spectrometry (GC-MS). Male offspring were subjected to body composition scanning followed by ex vivo global I/R. Cardiac signaling was determined by Western blotting. RESULTS: The body weights (BWs) of the GDM male offspring were significantly heavier than those of the control group from the age of 8 weeks; the heart weights (HWs) and HW/BW were also increased in the GDM group compared to the control group. The ex vivo post-I/R cardiac contractile function recovery was significantly compromised in the GDM male offspring. The phosphorylation of AMPK and ACC was elevated by ex vivo I/R in both groups, but to a significantly lesser extent in the GDM group. CONCLUSION: GDM male offspring rats have higher risks of overgrowth and intolerance to cardiac I/R, which may be due to a compromised AMPK signaling pathway.

Nutritional Supplementation for the Prevention and/or Treatment of Gestational Diabetes Mellitus.

PURPOSE OF REVIEW: Gestational diabetes mellitus (GDM) is a common pregnancy complication that has short- and long-term health implications for both the mother and child. While lifestyle modifications, insulin therapy, and oral agents such as metformin are effective, they can be difficult to adhere to, and there remain concerns over long-term effects of oral agents on the infant. Further, GDM has no proven preventive strategies, which could be more effective than treatment postdiagnosis. Nutritional supplements are an appealing, potentially safer, and better tolerated alternative to pharmaceuticals to treat and/or prevent GDM. Here, we review the existing evidence for nutritional supplementation for treatment and prevention of GDM. RECENT FINDINGS: There is limited evidence that myo-inositol, vitamins D and B6, magnesium, selenium, zinc, fatty acids, and probiotics might be beneficial for the prevention or treatment of GDM. There are very few studies for each nutrient, and the existing studies tend to have few participants. Where multiple studies of a nutrient exist, often those studies were conducted within the same country, limiting the generalizability of the findings, or alternatively there was no consensus across findings. There is limited evidence that nutritional supplementation of myo-inositol, vitamins D and B6, magnesium, selenium, zinc, fatty acids, and probiotics could improve glycemic control or prevent GDM. Our understanding is constrained by the small number of studies, small sample sizes in most studies, and by lack of consistency across findings. Further large, high-quality, randomized controlled trials are required to determine the efficacy of nutritional supplements to treat or prevent GDM.

Effect of sildenafil citrate treatment in the eNOS knockout mouse model of fetal growth restriction on long-term cardiometabolic outcomes in male offspring.

Fetal growth restriction (FGR) is associated with an increased risk of hypertension, insulin resistance, obesity and cardiovascular disease in adulthood. Currently there are no effective treatments to reverse the course of FGR. This study used the eNOS knockout mouse (eNOS-/-), a model of FGR, to determine the ability of sildenafil, a potential new treatment for FGR, to improve cardiovascular and metabolic outcomes in adult offspring following a complicated pregnancy. Pregnant eNOS-/- and C57BL/6J control dams were randomised to sildenafil treatment (0.2 mg/ml in drinking water) or placebo at day 12.5 of gestation until birth. After weaning, male offspring were randomised to either a high fat (HFD; 45% kcal from fat) or normal chow diet (ND), and raised to either postnatal day 90 or 150. Growth and body composition, glucose tolerance, insulin resistance, systolic blood pressure and vascular function were analysed at both time-points. eNOS-/- offspring were significantly smaller than their C57BL/6J controls at weaning and P90 (p < 0.01); at P150 they were a similar weight. Total adipose tissue deposition at P90 was significantly increased only in eNOS-/- mice fed a HFD (p < 0.001). At P150 both C57BL/6J and eNOS-/- offspring fed a HFD demonstrated significant adipose tissue deposition (p < 0.01), regardless of maternal treatment. Both diet and maternal sildenafil treatment had a significant effect on glucose tolerance. Glucose tolerance was significantly impaired in eNOS-/- mice fed a HFD (p < 0.01); this was significant in offspring from both sildenafil and vehicle treated mothers at P90 and P150. Glucose tolerance was also impaired in C57BL/6J mice fed a HFD at both P90 and P150 (p < 0.01), but only in those also exposed to sildenafil. In these C57BL/6J mice, sildenafil was associated with impaired insulin sensitivity at P90 (p = 0.020) but increased insulin resistance at P150 (p = 0.019). Exposure to sildenafil was associated with a significant increase in systolic blood pressure in eNOS-/- mice compared with their C57BL/6J diet controls at P150 (p < 0.05). Exposure to sildenafil had differing effects on vascular function in mesenteric arteries; it increased vasodilation in response to ACh in C57BL/6J mice, but was associated with a more constrictive phenotype in eNOS-/- mice. eNOS-/- mice demonstrate a number of impaired outcomes consistent with programmed cardiometabolic disease, particularly when faced with the 'second hit' of a HFD. Exposure to sildenafil treatment during pregnancy did not increase fetal growth or significantly improve adult metabolic or cardiac outcomes. Maternal sildenafil treatment was, however, associated with small impairments in glucose handling and an increase in blood pressure. This study highlights the importance of understanding the long-term effects of treatment during pregnancy in offspring from both complicated and healthy control pregnancies.

The Pathophysiology of Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM) is a serious pregnancy complication, in which women without previously diagnosed diabetes develop chronic hyperglycemia during gestation. In most cases, this hyperglycemia is the result of impaired glucose tolerance due to pancreatic ß-cell dysfunction on a background of chronic insulin resistance. Risk factors for GDM include overweight and obesity, advanced maternal age, and a family history or any form of diabetes. Consequences of GDM include increased risk of maternal cardiovascular disease and type 2 diabetes and macrosomia and birth complications in the infant. There is also a longer-term risk of obesity, type 2 diabetes, and cardiovascular disease in the child. GDM affects approximately 16.5% of pregnancies worldwide, and this number is set to increase with the escalating obesity epidemic. While several management strategies exist-including insulin and lifestyle interventions-there is not yet a cure or an efficacious prevention strategy. One reason for this is that the molecular mechanisms underlying GDM are poorly defined. This review discusses what is known about the pathophysiology of GDM, and where there are gaps in the literature that warrant further exploration.

Placental Nano-vesicles Target to Specific Organs and Modulate Vascular Tone In Vivo.

STUDY QUESTION: How do nano-vesicles extruded from normal first trimester human placentae affect maternal vascular function? SUMMARY ANSWER: Placental nano-vesicles affect the ability of systemic mesenteric arteries to undergo endothelium- and nitric oxide- (NO-) dependent vasodilation in vivo in pregnant mice. WHAT IS KNOWN ALREADY: Dramatic cardiovascular adaptations occur during human pregnancy, including a substantial decrease in total peripheral resistance in the first trimester. The human placenta constantly extrudes extracellular vesicles that can enter the maternal circulation and these vesicles may play an important role in feto-maternal communication. STUDY DESIGN, SIZE, DURATION: Human placental nano-vesicles were administered into CD1 mice via a tail vein and their localization and vascular effects at 30 min and 24 h post-injection were investigated. PARTICIPANTS/MATERIALS, SETTING, METHODS: Nano-vesicles from normal first trimester human placentae were collected and administered into pregnant (D12.5) or non-pregnant female mice. After either 30 min or 24 h of exposure, all major organs were dissected for imaging (n = 7 at each time point) while uterine and mesenteric arteries were dissected for wire myography (n = 6 at each time point). Additional in vitro studies using HMEC-1 endothelial cells were also conducted to investigate the kinetics of interaction between placental nano-vesicles and endothelial cells. MAIN RESULTS AND THE ROLE OF CHANCE: Nano-vesicles from first trimester human placentae localized to the lungs, liver and kidneys 24 h after injection into pregnant mice (n = 7). Exposure of pregnant mice to placental nano-vesicles for 30 min in vivo increased the vasodilatory response of mesenteric arteries to acetylcholine, while exposure for 24 h had the opposite effect (P < 0.05, n = 6). These responses were prevented by L-NAME, an NO synthase inhibitor. Placental nano-vesicles did not affect the function of uterine arteries or mesenteric arteries from non-pregnant mice. Placental nano-vesicles rapidly interacted with endothelial cells via a combination of phagocytosis, endocytosis and cell surface binding in vitro. LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: As it is not ethical to administer labelled placental nano-vesicles to pregnant women, pregnant CD1 mice were used as a model of pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: This is the first study to report the localization of placental nano-vesicles and their vascular effects in vivo. This work provides new insight into how the dramatic maternal cardiovascular adaptations to pregnancy may occur and indicates that placental extracellular vesicles may be important mediators of feto-maternal communication in a healthy pregnancy. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by the Faculty of Medical and Health Science (FMHS) School of Medicine PBRF research fund to L.W.C. M.T. is a recipient of a University of Auckland Health Research Doctoral Scholarship and the Freemasons Postgraduate Scholarship. No authors have any competing interests to disclose.

Effect of the anti-oxidant tempol on fetal growth in a mouse model of fetal growth restriction.

Fetal growth restriction (FGR) greatly increases the risk of perinatal morbidity and mortality and is associated with increased uterine artery resistance and levels of oxidative stress. There are currently no available treatments for this condition. The hypothesis that the antioxidant 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (Tempol) would improve uterine artery function and rescue fetal growth was tested in a mouse model of FGR, using the endothelial nitric oxide synthase knockout mouse (Nos3(-/-)). Pregnant Nos3(-/-) and control C57BL/6J mice were treated with the superoxide dismutase-mimetic Tempol (1 mmol/L) or vehicle from Gestational Day 12.5 to 18.5. Tempol treatment significantly increased pup weight (P < 0.05) and crown-rump length (P < 0.01) in C57BL/6J and Nos3(-/-) mice. Uterine artery resistance was increased in Nos3(-/-) mice (P < 0.05); Tempol significantly increased end diastolic velocity in Nos3(-/-) mice (P < 0.05). Superoxide production in uterine arteries did not differ between C57BL/6J and Nos3(-/-) mice but was significantly increased in placentas from Nos3(-/-) mice (P < 0.05). This was not reduced by Tempol treatment. Placental System A activity was reduced in Nos3(-/-) mice (P < 0.01); this was not improved by treatment with Tempol. Treatment of Nos3(-/-) mice with Tempol, however, was associated with reduced vascular density in the placental bed (P < 0.05). This study demonstrated that treatment with the antioxidant Tempol is able to improve fetal growth in a mouse model of FGR. This was associated with an increase in uterine artery blood flow velocity but not an improvement in uterine artery function or placental System A activity.

eNOS knockout mouse as a model of fetal growth restriction with an impaired uterine artery function and placental transport phenotype.

Fetal growth restriction (FGR) is the inability of a fetus to reach its genetically predetermined growth potential. In the absence of a genetic anomaly or maternal undernutrition, FGR is attributable to "placental insufficiency": inappropriate maternal/fetal blood flow, reduced nutrient transport or morphological abnormalities of the placenta (e.g., altered barrier thickness). It is not known whether these diverse factors act singly, or in combination, having additive effects that may lead to greater FGR severity. We suggest that multiplicity of such dysfunction might underlie the diverse FGR phenotypes seen in humans. Pregnant endothelial nitric oxide synthase knockout (eNOS(-/-)) dams exhibit dysregulated vascular adaptations to pregnancy, and eNOS(-/-) fetuses of such dams display FGR. We investigated the hypothesis that both altered vascular function and placental nutrient transport contribute to the FGR phenotype. eNOS(-/-) dams were hypertensive prior to and during pregnancy and at embryonic day (E) 18.5 were proteinuric. Isolated uterine artery constriction was significantly increased, and endothelium-dependent relaxation significantly reduced, compared with wild-type (WT) mice. eNOS(-/-) fetal weight and abdominal circumference were significantly reduced compared with WT. Unidirectional maternofetal (14)C-methylaminoisobutyric acid (MeAIB) clearance and sodium-dependent (14)C-MeAIB uptake into mouse placental vesicles were both significantly lower in eNOS(-/-) fetuses, indicating diminished placental nutrient transport. eNOS(-/-) mouse placentas demonstrated increased hypoxia at E17.5, with elevated superoxide compared with WT. We propose that aberrant uterine artery reactivity in eNOS(-/-) mice promotes placental hypoxia with free radical formation, reducing placental nutrient transport capacity and fetal growth. We further postulate that this mouse model demonstrates "uteroplacental hypoxia," providing a new framework for understanding the etiology of FGR in human pregnancy.

Interleukin-1 Receptor-1 Deficiency Impairs Metabolic Function in Pregnant and Non-Pregnant Female Mice.

SCOPE: Glucose intolerance during pregnancy is associated with short- and long-term maternal and offspring health consequences. In young male mice, knockout of the major pro-inflammatory mediator interleukin-1-receptor-1 (IL1R1) protects against high-fat diet (HFD)-induced glucose intolerance and metabolic dysfunction. This phenotype has not been examined during pregnancy. The hypothesis that IL1R1 depletion will protect females against HFD-induced glucose intolerance and metabolic dysfunction before, during, and post pregnancy is tested. METHODS AND RESULTS: C57BL/6J control and IL1R1 knockout (IL1R1-/- ) mice are randomized to either a control diet (10% kcal from fat) or HFD (45% kcal from fat), and three distinct cohorts are established: nulliparous, pregnant, and postpartum females. Contrary to the authors' hypothesis, it is found that IL1R1-/- does not protect against glucose intolerance in nulliparous or pregnant females, and while control HFD animals see a resolution of glucose tolerance postpartum, IL-1R1-/- mice remain impaired. These effects are accompanied by adipocyte hypertrophy, hyperleptinemia, and increased adipose tissue inflammatory gene expression. Maternal genotype differentially affects fetal growth in male and female fetuses, demonstrating sexual dimorphism in this genotype prior to birth. CONCLUSIONS: These findings suggest that IL1R1 signaling is important for normal metabolic functioning in females, during and outside of pregnancy.

Previous gestational diabetes impairs long-term endothelial function in a mouse model of complicated pregnancy.

Women who develop gestational diabetes mellitis (GDM) display endothelial dysfunction up to 1 yr after pregnancy, despite a return to normoglycemia. It is unknown whether this dysfunction was preexisting or whether GDM pregnancy leads to long-term endothelial dysfunction. A mouse model that spontaneously develops GDM (Lepr(db/+)) was used to determine whether the endothelial dysfunction that develops during GDM is evident in later life. Heterozygous and wild-type (WT) controls were allowed to litter once, then age to 9-10 mo, and were compared with virgin controls. Vascular function of small mesenteric arteries was assessed using wire myography. Concentration response curves to the thromboxane A(2)mimetic U46619 and the endothelium-dependent vasodilator methacholine were constructed. Superoxide production and peroxynitrite formation was also measured. Mice with previous GDM displayed blood glucose concentrations similar to previously pregnant WT mice (8.0 +/- 0.1 vs. 7.1 +/- 0.3 mmol/l, P > 0.05). Arteries from mice with previous GDM displayed increased sensitivity to U46619 (EC(50) 5.2 +/- 0.7 vs. 45.2 +/- 1.0 nmol/l, P < 0.01) and impaired endothelium-dependent relaxation compared with WT controls (29 +/- 8 vs. 58 +/- 16 percent relaxation, P < 0.05). This was associated with increased superoxide production (93.3 +/- 2.3 vs. 64.6 +/- 1.6 mean fluorescence intensity, P < 0.001) and increased peroxynitrite formation (173.5 +/- 11.0 vs. 57.4 +/- 16.2 mean fluorescence intensity, P < 0.01) compared with virgin controls. In summary, endothelial dysfunction was evident in mice with previous GDM compared with previously healthy pregnant mice or virgin controls. These data suggest that GDM affects endothelial function and may contribute to an increased risk of cardiovascular disease.

Interleukin 1 Receptor 1 Knockout and Maternal High Fat Diet Exposure Induces Sex-Specific Effects on Adipose Tissue Adipogenic and Inflammatory Gene Expression in Adult Mouse Offspring.

Background: The global incidence of obesity continues to rise, increasing the prevalence of metabolic diseases such as insulin resistance, dyslipidemia, and type 2 diabetes mellitus. Low-grade chronic inflammation, associated with the obese state, also contributes to the development of these metabolic comorbidities. Interleukin-1-receptor-1 (IL-1R1), a pro-inflammatory mediator, bridges the metabolic and inflammatory systems. In young male mice, deficiency of IL-1R1 (IL-1R1-/-) paired with a high-fat diet (HFD) offered beneficial metabolic effects, however in female mice, the same pairing led to metabolic dysfunction. Therefore, we examined the contribution of maternal HFD in combination with IL1R1-/- to metabolic health in adult offspring. Methods: Female C57BL/6 and IL-1R1-/- mice were randomly assigned to a control diet (10% kcal from fat) or HFD (45% kcal from fat) 10 days prior to mating and throughout gestation and lactation. Male and female offspring were housed in same-sex pairs post-weaning and maintained on control diets until 16 weeks old. At 15 weeks, an oral glucose tolerance test (OGTT) was performed to assess glucose tolerance. Histological analysis was carried out to assess adipocyte size and gene expression of adipogenic and inflammatory markers were examined. Results: IL-1R1-/- contributed to increased body weight in male and female adult offspring, irrespective of maternal diet. IL-1R1-/- and maternal HFD increased adipocyte size in the gonadal fat depot of female, but not male offspring. In female offspring, there was reduced expression of genes involved in adipogenesis and lipid metabolism in response to IL1R1-/- and maternal HFD. While there was an increase in inflammatory gene expression in response to maternal HFD, this appeared to be reversed in IL1R1-/- female offspring. In male offspring, there was no significant impact on adipogenic or lipid metabolism pathways. There was an increase in inflammatory gene expression in IL1R1-/- male offspring from HFD-fed mothers. Conclusion: This study suggests that IL-1R1 plays a complex and important role in the metabolic health of offspring, impacting adipogenesis, lipogenesis, and inflammation in a sex-specific manner.

Uterine artery function in a mouse model of pregnancy complicated by diabetes.

It has been demonstrated previously that endothelium-dependent vasodilatation is impaired in myometrial arteries from women with gestational diabetes, which may play a role in mediating complications observed in diabetic pregnancies. It is not known which aspects of endothelium-dependent vasodilatation are impaired, thus a mouse model of pregnancy complicated by streptozotocin-induced diabetes was established to investigate underlying mechanisms. Uterine arteries from term-pregnant, diabetic and control C57Bl6/J mice were assessed using acetylcholine (ACh; 10(-10)-10(-5)M) in the presence or absence of a nitric oxide (NO) synthase inhibitor (L-NNA; 10(-5)M), a cyclooxygenase (COX) inhibitor (indomethacin; 10(-5)M) or the two in combination. Sensitivity to ACh was comparable between diabetic and control mice. However, the contribution of endothelium-dependent vasodilators was significantly altered. L-NNA significantly inhibited the relaxation of arteries from diabetic compared to control mice (65+/-11% vs 18+/-6%; p<.05). L-NNA and indomethacin significantly inhibited the relaxation of arteries from diabetic mice compared to control (87+/-5% vs 33+/-14%; p<0.05). These data indicate that endothelium-dependent relaxation of the uterine artery of control, pregnant mice was largely mediated by the non-NO/non-COX component. Surprisingly, arteries from diabetic mice were primarily dependent on NO, which may affect compensatory capacity as the disease progresses.

Human Placental Growth Hormone Variant in Pathological Pregnancies.

Growth hormone (GH), an endocrine hormone, primarily secreted from the anterior pituitary, stimulates growth, cell reproduction, and regeneration and is a major regulator of postnatal growth. Humans have two GH genes that encode two versions of GH proteins: a pituitary version (GH-N/GH1) and a placental GH-variant (GH-V/GH2), which are expressed in the syncytiotrophoblast and extravillous trophoblast cells of the placenta. During pregnancy, GH-V replaces GH-N in the maternal circulation at mid-late gestation as the major circulating form of GH. This remarkable change in spatial and temporal GH secretion patterns is proposed to play a role in mediating maternal adaptations to pregnancy. GH-V is associated with fetal growth, and its circulating concentrations have been investigated across a range of pregnancy complications. However, progress in this area has been hindered by a lack of readily accessible and reliable assays for measurement of GH-V. This review will discuss the potential roles of GH-V in normal and pathological pregnancies and will touch on the assays used to quantify this hormone.

Absence of a gestational diabetes phenotype in the LepRdb/+ mouse is independent of control strain, diet, misty allele, or parity.

Treatment options for gestational diabetes (GDM) are limited. In order to better understand mechanisms and improve treatments, appropriate animal models of GDM are crucial. Heterozygous db mice (db/+) present with glucose intolerance, insulin resistance, and increased weight gain during, but not prior to, pregnancy. This makes them an ideal model for GDM. However, several recent studies have reported an absence of GDM phenotype in their colony. We investigated several hypotheses for why the phenotype may be absent, with the aim of re-establishing it and preventing further resources being wasted on an ineffective model. Experiments were carried out across two laboratories in two countries (New Zealand and China), and were designed to assess type of control strain, diet, presence of the misty allele, and parity as potential contributors to the lost phenotype. While hyperleptinemia and pre-pregnancy weight gain were present in all db/+mice across the four studies, we found no consistent evidence of glucose intolerance or insulin resistance during pregnancy. In conclusion, we were unable to acquire the GDM phenotype in any of our experiments, and we recommend researchers do not use the db/+ mouse as a model of GDM unless they are certain the phenotype remains in their colony.

The Effects of Myo-Inositol and B and D Vitamin Supplementation in the db/+ Mouse Model of Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM) is a growing concern, affecting an increasing number of pregnant women worldwide. By predisposing both the affected mothers and children to future disease, GDM contributes to an intergenerational cycle of obesity and diabetes. In order to stop this cycle, safe and effective treatments for GDM are required. This study sought to determine the treatment effects of dietary supplementation with myo-inositol (MI) and vitamins B2, B6, B12, and D in a mouse model of GDM (pregnant db/+ dams). In addition, the individual effects of vitamin B2 were examined. Suboptimal B2 increased body weight and fat deposition, decreased GLUT4 adipose tissue expression, and increased expression of inflammatory markers. MI supplementation reduced weight and fat deposition, and reduced expression of inflammatory markers in adipose tissue of mice on suboptimal B2. MI also significantly reduced the hyperleptinemia observed in db/+ mice, when combined with supplemented B2. MI was generally associated with adipose tissue markers of improved insulin sensitivity and glucose uptake, while the combination of vitamins B2, B6, B12, and D was associated with a reduction in adipose inflammatory marker expression. These results suggest that supplementation with MI and vitamin B2 could be beneficial for the treatment/prevention of GDM.

Evidence for a significant role of alpha 3-containing GABAA receptors in mediating the anxiolytic effects of benzodiazepines.

The GABA(A) receptor subtypes responsible for the anxiolytic effects of nonselective benzodiazepines (BZs) such as chlordiazepoxide (CDP) and diazepam remain controversial. Hence, molecular genetic data suggest that alpha2-rather than alpha3-containing GABA(A) receptors are responsible for the anxiolytic effects of diazepam, whereas the anxiogenic effects of an alpha3-selective inverse agonist suggest that an agonist selective for this subtype should be anxiolytic. We have extended this latter pharmacological approach to identify a compound, 4,2'-difluoro-5'-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-á]pyridin-3-yl]biphenyl-2-carbonitrile (TP003), that is an alpha3 subtype selective agonist that produced a robust anxiolytic-like effect in both rodent and non-human primate behavioral models of anxiety. Moreover, in mice containing a point mutation that renders alpha2-containing receptors BZ insensitive (alpha2H101R mice), TP003 as well as the nonselective agonist CDP retained efficacy in a stress-induced hyperthermia model. Together, these data show that potentiation of alpha3-containing GABA(A) receptors is sufficient to produce the anxiolytic effects of BZs and that alpha2 potentiation may not be necessary.

Maternal Administration of Sildenafil Citrate Alters Fetal and Placental Growth and Fetal-Placental Vascular Resistance in the Growth-Restricted Ovine Fetus.

Intrauterine growth restriction (IUGR) causes short- and long-term morbidity. Reduced placental perfusion is an important pathogenic component of IUGR; substances that enhance vasodilation in the uterine circulation, such as sildenafil citrate (sildenafil), may improve placental blood flow and fetal growth. This study aimed to examine the effects of sildenafil in the growth-restricted ovine fetus. Ewes carrying singleton pregnancies underwent insertion of vascular catheters, and then, they were randomized to receive uterine artery embolization (IUGR) or to a control group. Ewes in the IUGR group received a daily infusion of sildenafil (IUGR+SC; n=10) or vehicle (IUGR+V; n=8) for 21 days. The control group received no treatment (n=9). Umbilical artery blood flow was measured using Doppler ultrasound and the resistive index (RI) calculated. Fetal weight, biometry, and placental weight were obtained at postmortem after treatment completion. Umbilical artery RI in IUGR+V fell less than in controls; the RI of IUGR+SC was intermediate to that of the other 2 groups (mean±SEM for control versus IUGR+V versus IUGR+SC: ∆RI, 0.09±0.03 versus -0.01±0.02 versus 0.03±0.02; F(2, 22)=4.21; P=0.03). Compared with controls, lamb and placental weights were reduced in IUGR+V but not in IUGR+SC (control versus IUGR+V versus IUGR+SC: fetal weight, 4381±247 versus 3447±235 versus 3687±129 g; F(2, 24)=5.49; P=0.01 and placental weight: 559.7±35.0 versus 376.2±32.5 versus 475.2±42.5 g; F(2, 24)=4.64; P=0.01). Sildenafil may be a useful adjunct in the management of IUGR. An increase in placental weight and fall in fetal-placental resistance suggests that changes to growth are at least partly mediated by changes to placental growth rather than alterations in placental efficiency.

The Placental Variant of Human Growth Hormone Reduces Maternal Insulin Sensitivity in a Dose-Dependent Manner in C57BL/6J Mice.

The human placental GH variant (GH-V) is secreted continuously from the syncytiotrophoblast layer of the placenta during pregnancy and is thought to play a key role in the maternal adaptation to pregnancy. Maternal GH-V concentrations are closely related to fetal growth in humans. GH-V has also been proposed as a potential candidate to mediate insulin resistance observed later in pregnancy. To determine the effect of maternal GH-V administration on maternal and fetal growth and metabolic outcomes during pregnancy, we examined the dose-response relationship for GH-V administration in a mouse model of normal pregnancy. Pregnant C57BL/6J mice were randomized to receive vehicle or GH-V (0.25, 1, 2, or 5 mg/kg · d) by osmotic pump from gestational days 12.5 to 18.5. Fetal linear growth was slightly reduced in the 5 mg/kg dose compared with vehicle and the 0.25 mg/kg groups, respectively, whereas placental weight was not affected. GH-V treatment did not affect maternal body weights or food intake. However, treatment with 5 mg/kg · d significantly increased maternal fasting plasma insulin concentrations with impaired insulin sensitivity observed at day 18.5 as assessed by homeostasis model assessment. At 5 mg/kg · d, there was also an increase in maternal hepatic GH receptor/binding protein (Ghr/Ghbp) and IGF binding protein 3 (Igfbp3) mRNA levels, but GH-V did not alter maternal plasma IGF-1 concentrations or hepatic Igf-1 mRNA expression. Our findings suggest that at higher doses, GH-V treatment can cause hyperinsulinemia and is a likely mediator of the insulin resistance associated with late pregnancy.

Comparison of pulsatile vs. continuous administration of human placental growth hormone in female C57BL/6J mice.

Exogenous growth hormone has different actions depending on the method of administration. However, the effects of different modes of administration of the placental variant of growth hormone on growth, body composition and glucose metabolism have not been investigated. In this study, we examined the effect of pulsatile vs. continuous administration of recombinant variant of growth hormone in a normal mouse model. Female C57BL/6J mice were randomized to receive vehicle or variant of growth hormone (2 or 5 mg/kg per day) by daily subcutaneous injection (pulsatile) or osmotic pump for 6 days. Pulsatile treatment with 2 and 5 mg/kg per day significantly increased body weight. There was also an increase in liver, kidney and spleen weight via pulsatile treatment, whereas continuous treatment did not affect body weight or organ size. Pulsatile treatment with 5 mg/kg per day significantly increased fasting plasma insulin concentration, whereas with continuous treatment, fasting insulin concentration was not significantly different from the vehicle-treated control. However, a dose-dependent increase in fasting insulin concentration and decrease in insulin sensitivity, as assessed by HOMA, was observed with both modes of treatment. At 5 mg/kg per day, hepatic growth hormone receptor expression was increased compared to vehicle-treated animals, by both modes of administration. Pulsatile variant of growth hormone did not alter the plasma insulin-like growth factor-1 concentration, whereas a slight decrease was observed with continuous variant of growth hormone treatment. Neither pulsatile nor continuous treatment affected hepatic insulin-like growth factor-1 mRNA expression. Our findings suggest that pulsatile variant of growth hormone treatment was more effective in stimulating growth but caused marked hyperinsulinemia in mice.

G protein-coupled receptor 30 regulates trophoblast invasion and its deficiency is associated with preeclampsia.

BACKGROUND: Preeclampsia is known to be associated with reduced circulating levels of estrogen. The effects of estrogen in preeclampsia are normally mediated by the classical estrogen receptors. Intriguingly, a novel estrogen receptor, G protein-coupled receptor 30 (GPR30), has been recently found to play an important role in several estrogenic effects. However, the mechanisms by which GPR30 may mediate the development of preeclampsia remain unknown. METHOD: We observed that the expression of GPR30 in placental trophoblast cells is lower in preeclamptic placentas compared with normotensive controls. We then investigated the role of GPR30 in trophoblast cell invasion by utilizing placental explants and the immortalized human trophoblast cell line (HTR8/SVneo). RESULTS: The selective GPR30 agonist G1 and a general estrogen receptors agonist 17-ß-estradiol (E2) both improved trophoblast cells invasion by upregulating MMP9 expression and the PI3K-Akt signaling pathway. This effect was abolished by a selective GPR30 inhibitor G15, implying that GPR30 may be involved in regulating trophoblast invasion, and that down-regulation of this receptor may result in the development of preeclampsia. CONCLUSION: The present study suggests that GPR30 is a critical regulator of trophoblast cell invasion, and as such may be a potential therapeutic interventional target for preeclampsia and other pregnancy complications resulting from impaired trophoblast invasion.