Preeclampsia before fetal viability in women with primary antiphospholipid syndrome- materno-fetal outcomes in a series of 7 cases.

INTRODUCTION: Preeclampsia complicates about 10-17 % of pregnancies with antiphospholipid syndrome (APS). It is often severe and might occur sometimes at early gestation. The development of preeclampsia before fetal viability is a huge challenge for obstetricians and demands an intensive discussion regarding the therapeutical options. PATIENTS AND METHODS: We retrospectively reviewed the data of 7 women with primary APS who developed preeclampsia before 24 weeks of gestation. Plasma exchange had been performed in four of the cases and two women received corticosteroids. One of the women had received 20 mg of pravastatin daily, starting at 18 weeks of gestation. Neonatal outcome was: live birth in four cases and IUFD in three cases. The main pediatric complications were noted in a 28-week-old premature born boy, who developed severe IRDS and thrombocytopenia. At the present time, the boy continues to have a retarded status. DISCUSSION: This retrospective analysis revealed that women with APS can develop severe preeclampsia even before 20 weeks of gestation. Several management options for prolongation of pregnancy such as plasma exchange, pravastatin, LMHW, hydroxychloroquine/HCQ, or TNF-alpha blocker should be discussed with the patients. Optimal management of preeclampsia before 24 weeks of gestation usually depends on weighing the maternal and fetal complications from expectant management with prolongation of pregnancy versus the predominant fetal and neonatal risks of extreme prematurity from "aggressive" management with immediate delivery.

Dysregulation of solute carrier transporters in malaria-infected pregnant mice.

AIMS: Malaria in pregnancy (MiP) alters the expression of ATP-binding cassette efflux transporters in maternal and foetal tissues, as well as the placenta. Malaria induces oxidative stress, and pregnancy is associated with arginine deficiency. We hypothesized that reducing oxidative stress during MiP by supplementation with L-arginine, a NO precursor, would attenuate transcriptional changes in a second superfamily of transporters, solute carrier (SLC) transporters, and improve pregnancy outcomes. METHODS AND RESULTS: Pregnant BALB/c mice receiving L-arginine (1.2%) in water, or water alone, were infected with Plasmodium berghei ANKA on gestational day 13 and sacrificed on gestational day 19. Compared to controls, the mRNA of numerous SLC transporters was downregulated in maternal and foetal tissues, as well as in the placentas of infected mice. While supplementation with L-arginine did improve foetal viability, it did not improve the mRNA expression of oxidative stress markers, transporters nor other indices of foetal and maternal health. Moreover, amino acid uptake transporters were downregulated upon infection, which could potentially contribute to decreased foetal birthweight. CONCLUSIONS: Malaria in pregnancy significantly alters the expression of SLC transporters in maternal and foetal tissues as well as the placenta, regardless of L-arginine supplementation. Further studies to investigate methods of reducing oxidative stress in MiP are warranted.

Effects of intravenous infusion of E. coli lipopolysaccharide in early pregnant cows.

The objective was to characterize effects of Escherichia coli LPS (given i.v.) on corpus luteum (CL) and embryonic viability in early pregnant cattle. Eight non-lactating German Holstein cows were given 0.5 µg/kg LPS on 35 ± 3 day (mean ± s.e.m.) of pregnancy, whereas seven heifers, 41 ± 6 day pregnant, were given 10 mL saline (control group). Transrectal B-mode examinations of the CL were done at -1, 3, 6, 12, 24, 48, 72 and 96 h relative to treatment. Blood samples were collected at -1, 0.5, 1, 2, 3, 4, 6, 9, 12, 24, 48, 72 and 96 h. At 12 and 48 h, the CL was biopsied. None of the cows still in the experiment 10 day after LPS (n = 7) had embryonic loss. In LPS-treated cows, luteal area decreased (from 4.1 to 3.1 cm2; P ≤ 0.05) within 6 h and until 48 h. Luteal blood flow decreased by 39% (P ≤ 0.05) within the first 6 h after LPS, but returned to pre-treatment values by 48 h. Plasma P4 decreased by 62% (P ≤ 0.05), reached a nadir (2.7 ± 0.6 ng/mL) at 12 h after LPS and was not restored to pre-treatment (P ≤ 0.05). In luteal tissue, mRNAs for STAR and for FGF1 were lower (P ≤ 0.05) in LPS than in saline-treated cattle at 12 h, with no difference between groups at 48 h. Levels of mRNAs for CASP3 and FGF2 were not different between groups (P > 0.05) at 12 or 48 h after treatment. In conclusion, LPS transiently suppressed CL function, but did not induce embryonic mortality.

Maternal L-proline supplementation enhances fetal survival, placental development, and nutrient transport in mice†.

L-Proline (proline) in amniotic fluid was markedly increased during pregnancy in both pigs and sheep. However, in vivo data to support a beneficial effect of proline on fetal survival are not available. In this study, pregnant C57BL/6J mice were fed a purified diet supplemented with or without 0.50% proline from embryonic day 0.5 (E0.5) to E12.5 or term. Results indicated that dietary supplementation with proline to gestating mice enhanced fetal survival, reproductive performance, the concentrations of proline, arginine, aspartic acid, and tryptophan in plasma and amniotic fluid, while decreasing the concentrations of ammonia and urea in plasma and amniotic fluid. Placental mRNA levels for amino acid transporters, including Slc36a4, Slc38a2, Slc38a4, Slc6a14, and Na+/K+ ATPase subunit-1α (Atp1a1), fatty acid transporter Slc27a4, and glucose transporters Slc2a1 and Slc2a3, were augmented in proline-supplemented mice, compared with the control group. Histological analysis showed that proline supplementation enhanced labyrinth zone in the placenta of mice at E12.5, mRNA levels for Vegf, Vegfr, Nos2, and Nos3, compared with the controls. Western blot analysis showed that proline supplementation increased protein abundances of phosphorylated (p)-mTORC1, p-ribosomal protein S6 kinase (p70S6K), and p-eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), as well as the protein level of GCN2 (a negative regulator of mTORC1 signaling). Collectively, our results indicate a novel functional role of proline in improving placental development and fetal survival by enhancing placental nutrient transport, angiogenesis, and protein synthesis.

Arsenic trioxide exposure impairs testicular morphology in adult male mice and consequent fetus viability.

The acute promyelocytic leukemia (APL) is a rare disease, affecting 0.1/100,000 individuals globally. Despite significant advances in APL therapy, some patients still experience relapsed disease. Currently, arsenic trioxide (As2O3) was found to be effective in relapsed APL treatment and considered as standard treatment for these cases. However, it has been shown that exposure to As2O3 may exert adverse effects on the male reproductive system since this substance might also induce apoptosis of other important cell types including stem cells. Studies demonstrated that treatment with this metallic substance decreased plasma levels of testosterone and interfered with sperm parameters such as concentration, motility, and viability. In addition, As2O3 was found to produce significant damage to spermatocytes, which may be associated with testicular toxicity and consequent inhibition of spermatogenesis. The aim of this study was to determine sub-chronic treatment effects of As2O3 on sperm and testicular morphology, androgen receptor (AR) immunoreactivity in testes and epididymis, in addition to evaluation of fertility parameters in adult male mice. Thirty adult Swiss mice were divided into three experimental groups: control; received distilled water (vehicle) while treated received 0.3 or 3 mg/kg/day As2O3 subcutaneously, for 5 days per week, followed by 2 days of interruption, for 5 weeks. Results showed that As2O3 (1) decreased spermatozoa number, (2) produced seminiferous epithelium degeneration and exfoliation of germ cells tubule lumen (3) altered nucleus/cytoplasm proportion of Leydig cells and (4) reduced AR immunoreactivity in both Leydig and epithelial epididymal cells. Further, fetal viability tests demonstrated an increase in post-implantation loss in females that were mated with As2O3-treated males. Data indicate that As2O3 exposure altered the spermatogenic process and subsequently fetal viability.

Sodium hydrosulfide prevents hypertension and increases in vascular endothelial growth factor and soluble fms-like tyrosine kinase-1 in hypertensive pregnant rats.

Sodium hydrosulfide (NaHS) has presented antihypertensive and antioxidant effects and may reduce circulating soluble fms-like tyrosine kinase-1 (sFlt-1). We examined whether NaHS prevents maternal and fetal detrimental changes in a model of hypertension in pregnancy induced by N(G)-nitro-L-arginine methyl ester (L-NAME). Forty pregnant rats were divided into four groups (n = 10 per group): Norm-Preg, Preg + NaHS, HTN-Preg, or HTN-Preg + NaHS. Systolic blood pressure (SBP), number of viable fetuses, litter size, pups, and placentae weights were recorded. Circulating plasma sFlt-1, vascular endothelial growth factor (VEGF), myeloperoxidase (MPO), trolox equivalent antioxidant capacity (TEAC) levels, and biochemical determinants of nitric oxide (NO) formation were assessed. SBP values were elevated in the HTN-Preg group on gestational days 16, 18, and 20. However, HTN-Preg + NaHS group presented lower SBP values on days 18 and 20. Lower number of viable fetuses and litter size were found only in HTN-Preg group compared to other. Reductions in placental weight were found in HTN-Preg and HTN-Preg + NaHS groups. Increases in fetal weight were found only in Preg + NaHS group. Increases in circulating sFlt-1 and VEGF levels were observed only in HTN-Preg group compared to other. Higher MPO and lower TEAC plasma levels were found in HTN-Preg + NaHS and HTN-Preg groups. NO was diminished in HTN-Preg animals, and NaHS treatment increased NO levels only in hypertensive pregnant animals. Treatment with NaHS prevents hypertension in pregnancy and concomitantly reduces circulating plasma sFlt-1 and VEGF levels; this correlates with improved litter size with more viable fetuses and increase in NO levels. However, these beneficial effects presented no relation with oxidative stress.

Efficacy of 1,3-butanediol for enhancement of neonatal pig survival.

Pre-partum feeding of 1,3-butanediol to sows has been shown to improve the metabolic status and survival rate of neonatal pigs. To evaluate the efficacy of short-term, pre-partum feeding of 1,3-butanediol on pig and sow productivity on a large scale and low concentration was the focus of the research. The secondary objective was to determine if pre-partum feeding of 1,3-butanediol had any effect on survival rate and weight gain of lesser body weight pigs, sow body weight and subsequent sow reproductive performance. In a large commercial unit, 2537 sows were fed one of two pre-partum diets (0% or 4.55% 1,3-butanediol) on Day 108±3 of pregnancy. 1,3-butanediol provided 8% of the total metabolizable energy. Pigs born live in those litters were equalized by cross-fostering among sows receiving the same pre-partum diet. Pigs were weaned from the sows at 16±3 days post-partum and return of sows to estrus and conception rates were determined. Pre-partum feeding of 1,3-butanediol reduced (P=0.01) pre-weaning pig mortalities from 1.44 to 1.24 pigs per litter. The reduction in pig mortality was independent of length of 1,3-butanediol feeding (4 to 11 days). In a subset of 750 litters, four lesser birth-weight pigs from each litter were tagged and monitored to determine the effect of 1,3-butanediol on survival rates and pre-weaning weight gain of pigs with the greatest mortality risk. 1,3-butanediol reduced (P=0.01) pre-weaning mortality of these low birth weight pigs by 5.27%. Based on these data, short-term pre-partum feeding of 1,3-butanediol effectively improves pre-weaning pig productivity at a lower concentration than previously reported.

Efficacy of Ginkgo biloba on vaginal estrous and ovarian histological alterations for evaluating anti-implantation and abortifacient potentials in albino female mice.

Ginkgo extract, EGb 761 is known as a vasoregulatory variable for the conventional reproduction therapy. EGb 761 was orally administered in 0 (control), 3.7, 7.4, and 14.8 mg/kg bw/day for 28 days (thereafter mated with normal fertile male), from day 1 to day 7 of pregnancy or from the 10th to 18th day of pregnancy, respectively. Vaginal smears were performed daily. On 20th day of pregnancy, the females were killed by cervical dislocation and their kidneys, liver, brain, placenta, spleen and ovaries were removed and weighed. The ovaries were prepared for histological examinations, and then ovarian follicles were counted. Maternal toxicity, estrous cycle, reproductive hormones, ovarian follicle counts, resorption index, implantation index, fetal viability and fetuses, and placenta mean weights were evaluated. There was a dose-dependent ovarian toxic effect of EGb 761. Ovarian follicle counts, resorption index, implantation index, fetal viability were significantly reduced in 14.8 mg/kg bw/day dose. Treatment with 14.8 mg/kg bw/day EGb 761 induced disruption of estrous cycle and caused maternal toxicity, in addition to fetal toxicity. Therefore, the data obtained indicate that Ginkgo biloba extract at 14.8 mg/kg bw/day dose level exhibit toxic effect on reproductive cyclicity and could have anti-implantation and abotifacient properties in female mice.

The inhibitory effect of progesterone on lactogenesis during pregnancy is already evident by mid- to late gestation in rodents.

Lactogenesis is a very complex process highly dependent on hormonal regulation. In the present study the time-course of the inhibitory actions of progesterone on prolactin secretion, mammary gland morphology and lactogenesis from mid- to late gestation in rodents was investigated. Groups of pregnant rats were luteectomised or administered with mifepristone on Day 10, 13, 15 or 17 of gestation and decapitated 28 or 48h later. Whole-blood samples and the inguinal mammary glands were taken for determinations of hormone levels and for measurement of mammary content of casein and lactose and for tissue morphology analyses, respectively. Luteectomy or mifepristone evoked prolactin increases only after Day 17 of gestation. Mammary content of casein was increased by both treatments regardless of timing or duration. Mifepristone was less effective than luteectomy in inducing lactose production and the effect was only observed after Day 15 of gestation. Analysis of mammary gland morphology confirmed the observed effect of progesterone on lactogenesis. Both treatments triggered remarkable secretory activity in the mammary gland, even without a parallel epithelial proliferation, demonstrating that the mammary epithelium is able to synthesise milk compounds long before its full lobulo-alveolar development is achieved, provided that progesterone action is abolished. Thus, the present study demonstrates that progesterone is a potent hormonal switch for the prolactin and prolactin-like effects on mammary gland development and its milk-synthesising capacity during pregnancy, and that its inhibitory action is already evident by mid-pregnancy in rodents.

[The influence of calcium N-(5-hydroxynicotinoyl)-L-glutamate on reproductive function, prenatal and postnatal development of rats].

The safety of a new nootrope and neuroprotector--calcium N-(5-hydroxynicotinoyl)-L-glutamate (ampasse)--has been evaluated. It is shown that ampasse at a dose of 6.7 mg/kg (10 times the maximum therapeutic dose for humans) did not affect the reproductive function in experimental animals and did not produced any embryotoxic and teratogenic effects.

[Influence of hemicellulose based anticoagulant on male rat reproductive function].

Results of estimation of the effect of a new hemicellulose-based anticoagulant drug on the reproductive function of white male rats are presented. No negative impact on the fertility and breed was observed for the drug administered in doses of 5 and 25 mg/kg. However, in a dose of 50 mg/kg, the new drug negatively affected spermatogenesis and decrease the reproductive function of male rats.

Hazardous apoptotic effects of 2-bromopropane on maturation of mouse oocytes, fertilization, and fetal development.

2-Bromopropane (2-BP) is used as an alternative to ozone-depleting cleaning solvents. Previously, we reported that 2-BP has cytotoxic effects on mouse blastocysts and is associated with defects in subsequent development. Here, we further investigate the effects of 2-BP on oocyte maturation and subsequent pre- and post-implantation development, both in vitro and in vivo. Notably, 2-BP induced a significant reduction in the rates of oocyte maturation, fertilization, and in vitro embryonic development. Treatment of oocytes with 2-BP during in vitro maturation (IVM) resulted in increased resorption of postimplantation embryos and decreased fetal weights. Experiments with a mouse model disclosed that consumption of drinking water containing 20 µM 2-BP led to decreased oocyte maturation in vivo and fertilization in vitro, as well as impairment of early embryonic development. Interestingly, pretreatment with a caspase-3-specific inhibitor effectively prevented 2-BP-triggered hazardous effects, suggesting that embryonic impairment by 2-BP occurs via a caspase-dependent apoptotic process. A study using embryonic stem cells as the assay model conclusively demonstrated that 2-BP induces cell death processes through apoptosis and not necrosis, and inhibits early embryo development in mouse embryonic stem cells. These results collectively confirm the hazardous effects of 2-BP on embryos derived from pretreated oocytes.

Optimization of a novel nylon mesh container for human embryo ultrarapid vitrification.

OBJECTIVE: To evaluate the efficacy of a nylon mesh container in vitrification of human embryos and to determine the optimal osmotic pressure of the initial thawing solution. DESIGN: Retrospective analysis. SETTING: National Center for Child Health and Development, Tokyo, Japan. PATIENT(S): Infertile patients undergoing either in vitro fertilization or intracytoplasmic sperm injection in our hospital. INTERVENTION(S): Embryos, at the cleavage stage, were cryopreserved using the vitrification method in either a plastic straw or a nylon mesh container. The embryos were thawed using an initial osmotic pressure of either 0.5 M or 1.0 M sucrose with subsequent step-wise dilution. After thawing, the embryos were transferred to the uterus. MAIN OUTCOME MEASURE(S): Survival rate of blastomeres, embryo survival rate, implantation, and pregnancy rates, cancellation rate because of embryo damage. RESULT(S): Use of nylon mesh and the 1.0 M sucrose thawing solution significantly improved blastomere survival rate (98.0 +/- 1.0%, mean +/- SEM), pregnancy rate (41.0%) and implantation rate (32.3%). CONCLUSION(S): Vitrification using a nylon mesh container and subsequent thawing in a 1.0 M sucrose solution is an easy and inexpensive method that improves the reliability of embryo cryopreservation of embryos without adverse effects on clinical outcomes.

Reproductive toxicologic evaluations of Bulbine natalensis Baker stem extract in albino rats.

The effects of oral administration of aqueous extract of Bulbine natalensis Baker stem at daily doses of 25, 50, and 100mg/kg body weight on the reproductive function of Wistar rats were evaluated. The indices of mating and fertility success as well as quantal frequency increased after 7 days of treatment in all the dose groups except the 100mg/kg body weight group. The number of litters was not statistically different (P>0.05) from the control. Whereas the absolute weights of the epididymis, seminal vesicle, and prostate were not affected, that of the testes was significantly increased. The epididymal sperm count, motility, morphology, and viscosity were not different from the control after 7 days of treatment. The male rat serum testosterone, progesterone, luteinizing hormone, and follicle-stimulating hormone significantly increased in the 25 and 50mg/kg body weight groups, whereas the estradiol concentration decreased significantly at all the doses. The extract dose of 100mg/kg body weight decreased the serum testosterone and progesterone levels in male rats. The prolactin concentration was not affected by all the doses. All the indices of reproduction, maternal, embryo/fetotoxic, teratogenic, and reproductive hormones in the female rats were not statistically different from that of their control except the resorption index, which increased at the dose of 100mg/kg body weight of the extract. Histologic examination of the cross section of rat testes that received the extract at all the doses investigated revealed well-preserved seminiferous tubules with normal amount of stroma, normal population of spermatogenic and supporting cells, as well as normal spermatocytes within the lumen. The results revealed that the aqueous extract of Bulbine natalensis stem at doses of 25 and 50mg/kg body weight enhanced the success rate of mating and fertility due to increased libido as well as the levels of reproductive hormones in male rats. The absence of alterations in the reproductive parameters of female rats at doses of 25 and 50mg/kg body weight of Bulbine natalensis stem extract suggest that the extract is "safe" for use at these doses by females during the organogenic period of pregnancy, whereas the extract dose of 100mg/kg body weight portends a negative effect on some reproductive functions of male and female rats.

Evaluation of the safety and pharmacokinetics of the multi-targeted receptor tyrosine kinase inhibitor sunitinib during embryo-fetal development in rats and rabbits.

BACKGROUND: Angiogenesis plays a key role in embryo-fetal development and, based on nonclinical safety data, the majority of vascular endothelial growth factor (VEGF)-targeted antiangiogenic agents used in cancer therapy are not recommended during pregnancy. We investigated the effects of sunitinib (an oral inhibitor of multiple receptor tyrosine kinases [RTKs] including VEGF-receptors) on embryo-fetal development. METHODS: Presumed-pregnant Sprague-Dawley rats and New Zealand White rabbits received repeated daily oral doses of sunitinib (0-30 mg/kg/day), during the major period of organogenesis. Clinical/physical examinations were performed throughout the gestation phase, and blood samples were collected to determine systemic exposure. Necropsy (including uterine examination) was performed on all animals and fetal morphology was examined. RESULTS: The no-observed-adverse-effect level was 1-5 mg/kg/day for maternal toxicity and 3 mg/kg/day for developmental toxicity in rats; 1 and 0.5 mg/kg/day, respectively, in rabbits. Embryo-fetal toxicity included decreases in the number of live fetuses and increases in the numbers of resorptions and post-implantation/complete litter losses; these were observed at doses of > or =5 mg/kg/day in rats and 5 mg/kg/day in rabbits. Malformations included fetal skeletal malformations (generally thoracic/lumbar vertebral alterations) in rats and cleft lip/palate in rabbits. These developmental effects were observed at approximately 5.5- (rats) and approximately 0.3-times (rabbits) the human systemic exposure at the approved sunitinib dose (50 mg/day). CONCLUSIONS: Similar effects have been reported with the prototype monoclonal antibody bevacizumab. As is typically observed for potent inhibitors of RTKs involved in angiogenesis, sunitinib was associated with embryo-fetal developmental toxicity in rats and rabbits at clinically relevant dose levels.

Critical periods for the teratogenicity of immune-suppressant Leflunomide in mice.

Leflunomide has inhibitory effects on dihydroorotate-dehydrogenase activity and protein tyrosine kinase activity. In the present study, a single dose of 50 mg/kg Leflunomide was administered to pregnant mice on one of gestation days (GD)6-11. Characteristic external malformations were craniofacial defects following dosing on GD7, cleft palate on GD9, cleft palate and limb and tail deformities on GD10, and limb deformities on GD11. Skeletal examination revealed cervical to caudal vertebral malformations after treatment on GD7, GD8, GD9 or GD10. In the viscera, cardiovascular deformities were observed in the GD7 and GD9 Leflunomide-treated groups. These results demonstrate that multiple malformations were seen in various organs and most of the malformations observed appeared to be developmental stage-specific responses to Leflunomide treatment.

Inhibiting the teratogenicity of the immunosuppressant leflunomide in mice by supplementation of exogenous uridine.

Leflunomide is an immunosuppressant drug displaying teratogenicity in mice, rats, and rabbits. Its immunosuppressive effect occurs via inhibition of dihydroorotate dehydrogenase (DHODH) and tyrosine kinases. In this study, we coadministered Leflunomide and uridine, a precursor substance of pyrimidine nucleotides, to pregnant CD-1 mice, and examined whether or not a decreased level of intracellular pyrimidine nucleotides with inhibition of DHODH is related to the teratogenicity of Leflunomide. Then we examined the alteration of the nucleotide level in fetal tissue by Leflunomide and the effect of coadministered uridine. We administered Leflunomide with or without uridine to pregnant mice on gestation day 10, and used the vehicle of Leflunomide as a control. Leflunomide caused multiple malformations in all fetuses, but coadministration with uridine inhibited most of its teratogenicity. Leflunomide decreased the concentration of pyrimidine nucleotides, not purine nucleotides, whereas uridine coadministered with Leflunomide partially restored the level of pyrimidine nucleotides. These results indicate that the inhibitory effect of DHODH activity is related to the teratogenicity of Leflunomide.

Lung development in the Holtzman rat is adversely affected by gestational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that elicits a wide range of toxic effects on the developing organism. In this study, we demonstrate that the fetal and neonatal rat lung contains a responsive Ahr-signaling pathway which upon activation by a gestational exposure to TCDD, leads to altered lung development. Pregnant Holtzman rats received a single oral dose of TCDD (1.5 or 6 microg/kg) on gestation day (GD) 10 or a vehicle control with fetal and neonatal analysis occurring on GD20 or postnatal day (PND) 7. Components of the aryl hydrocarbon receptor (Ahr) signaling pathway (Ahr and Arnt) were identified in the fetal and neonatal lung tissue through the use of real-time PCR and immunohistochemical staining at both time points. Additionally, the Ahr-signaling pathway was found to be responsive to the gestational TCDD exposure as demonstrated by the induction of Cyp1a1, Cyp1b1, and Ahrr in both fetal and neonatal lung tissue. Morphometric analysis of GD20 and PND7 fixed lung tissue sections revealed that treated pups had significant decreases in total airspace area while having significantly wider tissue septa separating the airspaces as well as a decreased dry lung weight to body weight ratio when compared with controls; indicative of lung immaturity and hypoplasia. Finally, the assessment of respiratory mechanics on PND7 pups revealed functionally different pressure-volume curves in TCDD-exposed pups when compared with control animals. Together, these data identify a responsive Ahr-signaling pathway in the developing lung which may be related to the pulmonary immaturity and hypoplasia induced by TCDD and demonstrates that gestational exposure to TCDD alters lung development in such a manner that changes in lung morphology are associated with functional differences in respiratory mechanics.

Disruption of mitochondrial malate-aspartate shuttle activity in mouse blastocysts impairs viability and fetal growth.

The nutrient requirements and metabolic pathways used by the developing embryo transition from predominantly pyruvate during early cleavage stages to glucose at the blastocyst; however, the complexities involved in the regulation of metabolism at different developmental stages are not clear. The aims of this study were to examine the role of the malate-aspartate shuttle (MAS) in nutrient metabolism pathways in the developing mouse blastocyst and the consequences of impaired metabolism on embryo viability and fetal and placental growth. Eight-cell-stage mouse embryos were cultured in the presence of the MAS inhibitor amino-oxyacetate, with or without pyruvate as an energy substrate in the media. When the MAS was inhibited, the rate of glycolysis and lactate production was significantly elevated and glucose uptake reduced, relative to control cultured embryos in the presence of pyruvate. Despite these changes in embryo metabolism, this did not influence development to the blastocyst stage, but it did reduce the number of inner cell mass and trophectoderm cells. When these embryos were transferred to psuedopregnant females, inhibition of the MAS significantly reduced the proportion of embryos that implanted and developed into fetuses on Day 18 of pregnancy. Finally, fetal growth was reduced while placental weight was maintained, leading to a decreased fetal:placental weight ratio relative to control embryos. These results suggest that impaired metabolism of glucose in the blastocyst via the MAS alters the ability of the embryos to implant and form a pregnancy and leads to reduced fetal weight, likely via altered placental development and function.