Pregnancy Outcomes In Mice Research Articles

Decidual macrophage M1 polarization contributes to adverse pregnancy induced by Toxoplasma gondii PRU strain infection

Recent evidence indicates that macrophages at the maternal–fetal interface adapt to a phenotype characterized by alternative activation (M2 polarization) and exhibit immunosuppressive functions that favor the maintenance of pregnancy. The bias of M2 decidual macrophages toward M1 has been clinically linked to pregnancy-related complications, such as preeclampsia and preterm delivery. The aim of this study was to investigate the effect of Toxoplasma gondii PRU strain infection on the bias of decidual macrophage polarization and its contribution to adverse pregnancy outcomes. A mouse model with adverse pregnancy outcome was established by infection with T. gondii PRU strain and the expression levels of functional molecules in decidual macrophages of mice were measured. The results showed that T. gondii infection caused seriously adverse pregnancy outcome in mice. The placentae of infected mice showed obvious congestion and inflammatory cell infiltration. The expression of CD206, MHC-II, and arginase-1 considered as M2 markers was decreased in decidual macrophages after T. gondii infection, whereas the expression of CD80, CD86, iNOS, and cytokines TNF-α and IL-12 considered as M1 markers was increased. Furthermore, iNOS-positive expression was observed in the decidua basalis of infected mice. Our results indicated that T. gondii infection was responsible for the bias of M2 decidual macrophages toward M1, which changes the immunosuppressive microenvironment at the maternal–fetal interface and contributes to adverse pregnancy outcomes.

GnRH agonist improves pregnancy outcome in mice with induced adenomyosis by restoring endometrial receptivity.

PurposeAdenomyosis has a negative impact on female fertility. GnRH agonist treatment can improve pregnancy outcomes in women with adenomyosis. However, the impact of GnRH agonist upon endometrium receptivity of patients with adenomyosis remains unclear. In this study, endometrial receptivity and pregnancy outcome were investigated using a mouse model of adenomyosis.Materials and methodsAdenomyosis was induced in 12 female ICR mice, neonatally treated with tamoxifen, while another six female mice (control group) received solvent only. At 75 days, the induced adenomyosis group was randomly divided into two groups: an untreated group and a group treated with GnRH agonist (n = 6 each). Sixty days later, the mice were mated and pregnancy outcomes were observed and compared among the three groups (n = 6 each). In a parallel experiment using the same treatment regimes, uterus samples were collected on day 4 of pregnancy for immunohistochemistry, gene (quantitative polymerase chain reaction) and protein expression (Western blot), and scanning electron microscopy analyses.ResultsWe found that the average live litter size was reduced in the adenomyosis compared with control group (8 ± 0.56 versus 13 ± 0.71; P = 0.03). However, the litter size was significantly increased in the treated with GnRH agonist group compared with the untreated group (12 ± 0.35 versus 8 ± 0.56; P = 0.04). The uterine expression levels of Hoxa10, Hoxa11, Lif and integrin b3 mRNA and protein were decreased in the adenomyosis group, and were significantly increased after GnRH agonist treatment. Additionally, pinopodes were reduced in number and poorly developed in mice with induced adenomyosis. However, pinopodes were abundant and well-developed in the GnRH agonist treatment group.ConclusionAdenomyosis may have an adverse impact on endometrial receptivity and reduce pregnancy outcomes in mice. However, GnRH agonist may improve the pregnancy outcome by partially restoring endometrial receptivity.

Zika virus infection in immunocompetent pregnant mice causes fetal damage and placental pathology in the absence of fetal infection

Zika virus (ZIKV) infection during human pregnancy may cause diverse and serious congenital defects in the developing fetus. Previous efforts to generate animal models of human ZIKV infection and clinical symptoms often involved manipulating mice to impair their Type I interferon (IFN) signaling, thereby allowing enhanced infection and vertical transmission of virus to the embryo. Here, we show that even pregnant mice competent to generate Type I IFN responses that can limit ZIKV infection nonetheless develop profound placental pathology and high frequency of fetal demise. We consistently found that maternal ZIKV exposure led to placental pathology and that ZIKV RNA levels measured in maternal, placental or embryonic tissues were not predictive of the pathological effects seen in the embryos. Placental pathology included trophoblast hyperplasia in the labyrinth, trophoblast giant cell necrosis in the junctional zone, and loss of embryonic vessels. Our findings suggest that, in this context of limited infection, placental pathology rather than embryonic/fetal viral infection may be a stronger contributor to adverse pregnancy outcomes in mice. Our finding demonstrates that in immunocompetent mice, direct viral infection of the embryo is not essential for fetal demise. Our immunologically unmanipulated pregnancy mouse model provides a consistent and easily measurable congenital abnormality readout to assess fetal outcome, and may serve as an additional model to test prophylactic and therapeutic interventions to protect the fetus during pregnancy, and for studying the mechanisms of ZIKV congenital immunopathogenesis.

The Adverse Effects of Auditory Stress on Mouse Uterus Receptivity and Behaviour

Stress during gestation has harmful effects on pregnancy outcome and can lead to spontaneous abortion. Few studies, however, have addressed the impact of gestational stress, particularly auditory stress, on behavioural performance and pregnancy outcome in mice. This study aimed to examine the effect of two types of gestational stress on uterus receptivity and behavioural performance. Pregnant C57BL/6 mice were randomly assigned to either auditory or physical stress conditions or a control condition from gestational days 12–16. The auditory stress regimen used loud 3000 Hz tone, while the physical stressor consisted of restraint and exposure to an elevated platform. Three behavioural tests were performed in the dams after weaning. Uterine receptivity was investigated by counting the number of sites of implantation and fetal resorption. Also, the offspring survival rates during the early postnatal period were calculated. Auditory stress caused an increase in anxiety-like behaviour, reduced time spent exploring new object/environment, and reduced balance when compared to the physical stress and control groups. Auditory stress also caused higher rates of resorbed embryos and reduction of litter size. Our results suggest that the adverse effect of noise stress is stronger than physical stress for both uterus receptivity and behavioural performance of the dams.

Airway exposure to multi-walled carbon nanotubes disrupts the female reproductive cycle without affecting pregnancy outcomes in mice

BackgroundThe use of multiwalled carbon nanotubes (MWCNT) is increasing due to a growing use in a variety of products across several industries. Thus, occupational exposure is also of increasing concern, particularly since airway exposure to MWCNTs can induce sustained pulmonary acute phase response and inflammation in experimental animals, which may affect female reproduction. This proof-of-principle study therefore aimed to investigate if lung exposure by intratracheal instillation of the MWCNT NM-400 would affect the estrous cycle and reproductive function in female mice.ResultsEstrous cycle regularity was investigated by comparing vaginal smears before and after exposure to 67 μg of NM-400, whereas reproductive function was analyzed by measuring time to delivery of litters after instillation of 2, 18 or 67 μg of NM-400. Compared to normal estrous cycling determined prior to exposure, exposure to MWCNT significantly prolonged the estrous cycle during which exposure took place, but significantly shortened the estrous cycle immediately after the exposed cycle. No consistent effects were seen on time to delivery of litter or other gestational or litter parameters, such as litter size, sex ratio, implantations and implantation loss.ConclusionLung exposure to MWCNT interfered with estrous cycling. Effects caused by MWCNTs depended on the time of exposure: the estrous stage was particularly sensitive to exposure, as animals exposed during this stage showed a higher incidence of irregular cycling after exposure. Our data indicates that MWCNT exposure may interfere with events leading to ovulation.

Fluorene-9-bisphenol is anti-oestrogenic and may cause adverse pregnancy outcomes in mice

Bisphenol A (BPA) is used in the production of plastic but has oestrogenic activity. Therefore, BPA substitutes, such as fluorene-9-bisphenol (BHPF), have been introduced for the production of so-called ‘BPA-free’ plastics. Here we show that BHPF is released from commercial ‘BPA-free’ plastic bottles into drinking water and has anti-oestrogenic effects in mice. We demonstrate that BHPF has anti-oestrogenic activity in vitro and, in an uterotrophic assay in mice, induces low uterine weight, atrophic endometria and causes adverse pregnancy outcomes, even at doses lower than those of BPA for which no observed adverse effect have been reported. Female mice given water containing BHPF released from plastic bottles, have detectable levels of BHPF in serum, low uterine weights and show decreased expressions of oestrogen-responsive genes. We also detect BHPF in the plasma of 7/100 individuals, who regularly drink water from plastic bottles. Our data suggest that BPA substitutes should be tested for anti-oestrogenic activity and call for further study of the toxicological effects of BHPF on human health.

Curcumin inhibits placental inflammation to ameliorate LPS-induced adverse pregnancy outcomes in mice via upregulation of phosphorylated Akt.

Excessive inflammation results in adverse pregnancy outcomes, including embryonic resorption, fetal growth restriction, and preeclampsia. This study investigated whether curcumin, a highly safe anti-inflammation drug, had protective effect on lipopolysaccharide (LPS)-treated pregnant mice. A mouse model of LPS-induced adverse pregnancy outcomes was generated by daily administering LPS from GD 13.5 to GD 16.5. Curcumin was given from GD 0.5. The effects of curcumin on maternal hypertension, proteinuria, pregnancy outcomes, as well as proinflammatory factors, chemokines, Akt, JNK, and P38 levels in placenta were examined. Systolic blood pressure (156.6±5.056 versus 125.5±3.617mmHg; P<0.05) and proteinuria (22.36±2.22 versus 12.70±1.04mg/L; P<0.05) were decreased in the LPS+curcumin-treated group,as compared with the LPS-treated group. Curcumin also increased the number of live pups, fetal weight, and placental weight, while it decreased fetal resorption rate. Moreover, increased placental TNF-α, IL-1β, and IL-6 expressions in LPS-treated group were significantly suppressed after curcumin administration. Furthermore, decreased p-Akt level in placenta induced by LPS was improved by curcumin. Of note, the expression of p-Akt increased by curcumin was accompanied by the decreased chemokines MCP-1 and MIP-1 levels and fewer CD68-positive macrophages in the placenta. Curcumin inhibited the expression of proinflammatory factors and macrophage infiltration in placenta and ameliorated LPS-induced adverse pregnancy outcomes in mice by inhibiting inflammation via upregulation of phosphorylated Akt.

Association of FOXD1 variants with adverse pregnancy outcomes in mice and humans.

Recurrent spontaneous abortion (RSA) is a common cause of infertility, but previous attempts at identifying RSA causative genes have been relatively unsuccessful. Such failure to describe RSA aetiological genes might be explained by the fact that reproductive phenotypes should be considered as quantitative traits resulting from the intricate interaction of numerous genetic, epigenetic and environmental factors. Here, we studied an interspecific recombinant congenic strain (IRCS) of Mus musculus from the C57BL6/J strain of mice harbouring an approximate 5 Mb DNA fragment from chromosome 13 from Mus spretus mice (66H-MMU13 strain), with a high rate of embryonic resorption (ER). Transcriptome analyses of endometrial and placental tissues from these mice showed a deregulation of many genes associated with the coagulation and inflammatory response pathways. Bioinformatics approaches led us to select Foxd1 as a candidate gene potentially related to ER and RSA. Sequencing analysis of Foxd1 in the 66H-MMU13 strain, and in 556 women affected by RSA and 271 controls revealed non-synonymous sequence variants. In vitro assays revealed that some led to perturbations in FOXD1 transactivation properties on promoters of genes having key roles during implantation/placentation, suggesting a role of this gene in mammalian implantation processes.

Teratogenic Effect of Verbascoside, Main Constituent of Lippia citriodora Leaves, in Mice.

Verbascoside (acteoside), a phenyl propanoid glycoside, comprises 0.5 to 3.5 % dry weight of Lippia citriodora leaves. A wide range of biological activities are attributed to verbascoside including anti-inflammatory, antioxidant, anti-bacterial, anti-tumor, anti-fungal, photoprotective as well as chelating effects. The objective of this study is to evaluate the effect of verbascoside on pregnancy outcome in mice. Timed-pregnant mice received doses of 1g/kg/day verbascoside or the vehicle control during organogenesis, intraperitoneally. Maternal body weights were measured throughout pregnancy. The litters were examined for external malformations and skeletal abnormalities. Then they were stained with Alizarin red S and Alcian blue. Maternal exposure to verbascoside throughout pregnancy did not influence the mean of maternal weight gain. Statistically significant difference was not found in mean number of implantation sites, live and resorbed fetuses between control and experiment groups. Our data demonstrate that the main component of L. citriodora, verbascoside using during organogenesis possesses no risk to fetuses. However, more research projects are needed to confirm these findings and determine the exact effects of verbascoside on human embryo development.

Teratogenic effect of Lippia citriodora leaves aqueous extract in mice.

Safety of Lippia citriodora, as a herbal remedy, in pregnancy has not yet been evaluated. This study aimed to identify the effect of L. citriodora aqueous extract on pregnancy outcome in mice. Timed-pregnant mice received doses of 0.5 g/kg/day L. citriodora aqueous extract or the vehicle control during organogenesis, intraperitoneally. Maternal body weights were measured throughout the pregnancy. The litters were examined for external malformations and skeletal abnormalities. Fetuses were stained with Alizarin red S and Alcian blue. There were no significant differences in mean maternal weight gain during pregnancy between groups. Also, no significant differences were observed in mean number of implantation, live and resorbed fetuses between control and treated groups. The prevalence of all types of deformity was low and similar to control group (%1.11). The results of this study show that moderate consumption of L. citriodora as an infusion or tea appears to be safe to be used during pregnancy and does not have toxic effects on development of mouse embryo.

Excess Maternal Fructose Consumption Increases Fetal Loss and Impairs Endometrial Decidualization in Mice.

The most significant increase in metabolic syndrome over the previous decade occurred in women of reproductive age, which is alarming given that metabolic syndrome is associated with reproductive problems including subfertility and early pregnancy loss. Individuals with metabolic syndrome often consume excess fructose, and several studies have concluded that excess fructose intake contributes to metabolic syndrome development. Here, we examined the effects of increased fructose consumption on pregnancy outcomes in mice. Female mice fed a high-fructose diet (HFrD) for 6 weeks developed glucose intolerance and mild fatty liver but did not develop other prominent features of metabolic syndrome such as weight gain, hyperglycemia, and hyperinsulinemia. Upon mating, HFrD-exposed mice had lower pregnancy rates and smaller litters at midgestation than chow-fed controls. To explain this phenomenon, we performed artificial decidualization experiments and found that HFrD consumption impaired decidualization. This appeared to be due to decreased circulating progesterone as exogenous progesterone administration rescued decidualization. Furthermore, HFrD intake was associated with decreased bone morphogenetic protein 2 expression and signaling, both of which were restored by exogenous progesterone. Finally, expression of forkhead box O1 and superoxide dismutase 2 [Mn] proteins were decreased in the uteri of HFrD-fed mice, suggesting that HFrD consumption promotes a prooxidative environment in the endometrium. In summary, these data suggest that excess fructose consumption impairs murine fertility by decreasing steroid hormone synthesis and promoting an adverse uterine environment.

Compatibility of a novel thrombospondin-1 analog with fertility and pregnancy in a xenograft mouse model of endometriosis.

Endometriosis is a gynecological disease defined by the growth of endometrium outside of the uterus. Although endometriosis contributes to 50% of female infertility cases, medical treatments are incompatible with pregnancy. Angiogenesis, the growth of blood vessels from existing vasculature, plays a crucial role in endometriotic lesion growth and survival. Previously, we demonstrated the effectiveness of thrombospondin-1 analog, ABT-898 (Abbott Laboratories) to inhibit endometriotic lesion vascularization in mice. We have now evaluated the trans-generational implications of ABT-898 treatment before and during mouse pregnancy. We hypothesized that ABT-898 would target lesion vasculature without affecting pregnancy, offspring development, or ovarian and uterine vascularity in mice. Endometriosis was induced using human endometrium in β-estradiol-primed BALB/c-Rag-2-/-Il2rγ-/- mice receiving intraperitoneal injections of ABT-898 (25 mg/kg) or 5% dextrose control for 21 days. Ultrasound assessment of lesion vascularization revealed a reduction in blood flow supplying treated lesions. Excised ABT-898 treated lesions stained for CD31+ endothelial cells exhibited a decrease in microvessel density. Following confirmation of estrous cycling, mice were bred and treated with ABT-898 on gestation days 7, 9, 11, 13, 15, 17, and 19. ABT-898 did not affect estrous cycling or pregnancy parameters including litter size across generations and offspring weight gain. Quantification of angiogenic cytokine plasma levels revealed no significant differences between treatment groups. Vimentin staining of the uterus and ovary revealed no observable effects of ABT-898. Similarly, no obvious histological anomalies were observed in the kidney, liver, ovary, or uterus following ABT-898 treatment. These results suggest that ABT-898 effectively inhibit endometriotic lesion vascularization without affecting trans-generational pregnancy outcomes in mice.

Abnormal pregnancy outcomes in mice using an induced periodontitis model and the haematogenous migration of Fusobacterium nucleatum sub-species to the murine placenta.

ObjectivesTo investigate if there is subspecies specific migration to the placenta by Fusobacterium nucleatum (Fn) and to determine whether experimentally induced periodontitis results in adverse pregnancy outcomes (APO) in mice.MethodsPeriodontitis was induced in pregnant mice using an inoculum of Fn and Porphyromonas gingivalis. In parallel, four sub-species of Fn were individually injected into the circulatory system. At day 18 of gestation, the placenta, liver, spleen and blood were harvested and litter size, number of viable fetuses and resorptions, maternal, fetal and placenta weights were recorded. For the direct inoculation group, some mice were allowed to deliver for assessment of length of gestation, litter size, maternal, placental and pup weight. The presence of Fn was assessed by PCR and inflammatory mediators were measured by ELISA or multiplex analysis.ResultsMice with alveolar bone loss, a marker of periodontitis, demonstrated significantly higher fetal weights (p = 0.015) and fetal/placental weight ratios (p = 0.030). PCR analysis of maternal organs did not identify Fn in any extracted tissues. In mice that received direct injection of Fn subspecies, varying degrees of APO were observed including preterm birth, intrauterine growth restriction, and fetal loss. Haematogenous spread of only Fn subsp. nucleatum to the placenta was confirmed. Litter size was significantly smaller (p = 0.023) and the number of resorptions was higher in inoculated versus control groups. Mice injected with subsp. nucleatum had significantly increased circulating CRP levels (p = 0.020) compared to controls while the mice with induced periodontitis had increased levels of IL-6 (p = 0.047) and IL-8 (p = 0.105).ConclusionsPeriodontitis in mice elevated fetal weight and the fetal weight/placental weight ratio. This study found that subsp. nucleatum migrated haematogenously to the placenta, leading to APO in mice. The study supports the potential role of Fn in the association between periodontitis and APO.

Developmental exposure of mice to dioxin promotes transgenerational testicular inflammation and an increased risk of preterm birth in unexposed mating partners.

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly known as dioxin) is a ubiquitous environmental contaminant and known endocrine disruptor. Using a mouse model, we previously found that adult female mice exposed in utero to TCDD (F1 generation) as well as multiple subsequent generations (F2-F4) exhibited reduced fertility and an increased incidence of spontaneous preterm birth. Additional studies revealed that male F1 mice with a similar in utero/developmental TCDD exposure also exhibited diminished fertility and conferred an increased risk of preterm birth to their unexposed mating partners. Herein, we extend these previous observations, reporting that reduced fertility in male F1 mice is linked to testicular inflammation which coincides with apoptosis of developing spermatocytes, sub-fertility and an increased risk of preterm birth in their unexposed mating partners. Significantly, in the absence of additional toxicant exposure, testicular inflammation and reduced fertility persisted in F2 and F3 males and their control mating partners also frequently exhibited spontaneous preterm birth. Although a steady, global decline in male fertility has been noted over the last few decades, the reasons for these changes have not been firmly established. Likewise, the PTB rate in the U.S. and other countries has paralleled industrial development, suggesting a possible relationship between environmental toxicant exposure and adverse pregnancy outcomes. Most current clinical strategies to prevent preterm birth are focused solely on the mother and have yielded limited benefits. In contrast, our studies strongly suggest that the preconception testicular health of the father is a critical determinant of pregnancy outcomes in mice. Future clinical studies should examine the potential contribution of the male to gestation length in women and whether efforts to reduce the incidence of preterm birth should be initiated in both parents prior to pregnancy.

Excessive Intrauterine Fluid Cause Aberrant Implantation and Pregnancy Outcome in Mice

The normal intrauterine fluid environment is essential for embryo implantation. In hydrosalpinx patients, the implantation and pregnancy rates are markedly decreased after IVF–embryo transfer, while salpingectomy could significantly improve the pregnancy rates. The leakage of hydrosalpinx fluid into the endometrial cavity was supposed to be the major cause for impaired fertility. However, the underlying mechanisms of hydrosalpinx fluids on implantation and ongoing pregnancy were not fully understood and remain controversial regarding its toxicity. In present study, by infusing different volume of non-toxic fluid (0.9% saline) into uterine lumen before embryo implantation in mice (Day4 08:30), we found that while the embryos were not “flushed out” from the uteri, the timing of implantation was deferred and normal intrauterine distribution (embryo spacing) was disrupted. The abnormal implantation at early pregnancy further lead to embryo growth retardation, miscarriage and increased pregnancy loss, which is similar to the adverse effects observed in hydrosalpinx patients undergoing IVF-ET. We further examined uterine receptivity related gene expression reported to be involved in human hydrosalpinx (Lif, Hoxa10, Integrin α(v) and β(3)). The results showed that expression of integrin α(v) and β(3) were increased in the fluid infused mouse uteri, implicating a compensatory effect to cope with the excessive fluid environment. Our data suggested that the adverse effects of excessive non-toxic luminal fluid on pregnancy are primarily due to the mechanical interference for normal timing and location of embryo apposition, which might be the major cause of decreased implantation rate in IVF-ET patients with hydrosalpinx.

Effects of Ureaplasma parvum lipoprotein multiple-banded antigen on pregnancy outcome in mice

Ureaplasma spp. are members of the family Mycoplasmataceae and have been considered to be associated with chorioamnionitis and preterm delivery. However, it is unclear whether Ureaplasma spp. have virulence factors related to these manifestations. The purpose of the present study was to determine whether the immunogenic protein multiple-banded antigen (MBA) from Ureaplasma parvum is a virulence factor for preterm delivery. We partially purified MBA from a type strain and clinical isolates of U. parvum, and also synthesized a diacylated lipopeptide derived from U. parvum, UPM-1. Using luciferase assays, both MBA-rich fraction MRF and UPM-1 activated the NF-κB pathway via TLR2. UPM-1 upregulated IL-1β, IL-6, IL-12p35, TNF-α, MIP2, LIX, and iNOS in mouse peritoneal macrophage. MRF or UPM-1 was injected into uteri on day 15 of gestation on pregnant C3H/HeN mice. The intrauterine MRF injection group had a significantly higher incidence of intrauterine fetal death (IUFD; 38.5%) than the control group (14.0%). Interestingly, intrauterine injection of UPM-1 caused preterm deliveries at high concentration (80.0%). In contrast, a low concentration of UPM-1 induced a significantly higher rate of fetal deaths (55.2%) than the control group (14.0%). The placentas of the UPM-1 injection group showed neutrophil infiltration and increased iNOS protein expression. Our data indicate that MBA from the clinical isolate of U. parvum is a potential virulence factor for IUFD and preterm delivery in mice and that the N-terminal diacylated lipopeptide is essential for the initiation of inflammation.

Aldosterone deficiency adversely affects pregnancy outcome in mice

Circulating aldosterone levels are increased in human pregnancy. Inadequately low aldosterone levels as present in preeclampsia, a life-threatening disease for both mother and child, are discussed to be involved in its pathogenesis or severity. Moreover, inactivating polymorphisms in the aldosterone synthase gene have been detected in preeclamptic women. Here, we used aldosterone synthase-deficient (AS(-/-)) mice to test whether the absence of aldosterone is sufficient to impair pregnancy or even to cause preeclampsia. AS(-/-) and AS(+/+) females were mated with AS(+/+) and AS(-/-) males, respectively, always generating AS(+/-) offspring. With maternal aldosterone deficiency in AS(-/-) mice, systolic blood pressure was low before and further reduced during pregnancy with no increase in proteinuria. Yet, AS(-/-) had smaller litters due to loss of fetuses as indicated by a high number of necrotic placentas with massive lymphocyte infiltrations at gestational day 18. Surviving fetuses and their placentas from AS(-/-) females were smaller. High-salt diet before and during pregnancy increased systolic blood pressure only before pregnancy in both genotypes and abolished the difference in blood pressure during late pregnancy. Litter size from AS(-/-) was slightly improved and the differences in placental and fetal weights between AS(+/+) and AS(-/-) mothers disappeared. Overall, an increased placental efficiency was observed in both groups paralleled by a normalization of elevated HIF1α levels in the AS(-/-) placentas. Our results demonstrate that aldosterone deficiency has profound adverse effects on placental function. High dietary salt intake improved placental function. In this animal model, aldosterone deficiency did not cause preeclampsia.

OS058. Aldosterone deficiency adversely affects pregnancy outcome in mice

In pregnancy, plasma volume is expanded due to high aldosterone levels to support placental perfusion and fetal nutrition. Inadequately low aldosterone levels as present in preeclampsia, a life-threatening disease for both mother and child, are discussed to be involved in its pathogenesis or severity. We used aldosterone synthase deficient (AS(-/-)) mice to test whether the absence of aldosterone is sufficient to impair pregnancy or even to cause preeclampsia. AS(-/-) and AS(+/+) females were mated with AS(+/+) and AS(-/-) males, respectively, always generating AS(+/-) offspring. Blood pressure was measured by tail cuff, fetal and placental number and size as well as placental histology were assessed. Placental expression of HIF-1αand angiogenic factors was assessed by semiquantitative RT-PCR. With maternal aldosterone deficiency in AS(-/-) mice, systolic blood pressure was low before and further reduced during pregnancy and with no increase in proteinuria. Yet, AS(-/-) had smaller litters due to loss of fetuses as indicated by a high number of necrotic placentas with massive lymphocyte infiltrations at gestational day 18. Surviving fetuses and their placentas from AS(-/-) females were smaller. High salt diet before and during pregnancy increased systolic blood pressure only before pregnancy in both genotypes and reduced blood pressure during late pregnancy as compared to normal salt controls. Litter size from AS(-/-) was slightly improved and the differences in placental and fetal weights between AS(+/+) and AS(-/-) mothers disappeared. Overall an increased placental efficiency was observed in both groups. Our results demonstrate that aldosterone deficiency has profound adverse effects on placental function. High dietary salt intake improved placental function and lowered blood pressure in wild-type mice. In this animal model, aldosterone deficiency did not cause preeclampsia.

Altered pregnancy outcomes in mice following treatment with the hyperglycaemia mimetic, glucosamine, during the periconception period

Exposure of cumulus-oocyte complexes to the hyperglycaemia mimetic, glucosamine, during in vitro maturation impairs embryo development, potentially through upregulation of the hexosamine biosynthesis pathway. This study examined the effects of in vivo periconception glucosamine exposure on reproductive outcomes in young healthy mice, and further assessed the effects in overweight mice fed a high-fat diet. Eight-week-old mice received daily glucosamine injections (20 or 400mgkg(-1)) for 3-6 days before and 1 day after mating (periconception). Outcomes were assessed at Day 18 of gestation. Glucosamine treatment reduced litter size independent of dose. A high-fat diet (21% fat) for 11 weeks before and during pregnancy reduced fetal size. No additional effects of periconception glucosamine (20mgkg(-1)) on pregnancy outcomes were observed in fat-fed mice. In 16-week-old mice fed the control diet, glucosamine treatment reduced fetal weight and increased congenital abnormalities, but did not alter litter size. As differing effects of glucosamine were observed in 8-week-old and 16-week-old mice, maternal age effects were assessed. Periconception glucosamine at 8 weeks reduced litter size, whereas glucosamine at 16 weeks reduced fetal size. Thus, in vivo periconception glucosamine exposure perturbs reproductive outcomes in mice, with the nature of the outcomes dependent upon maternal age.

Effects of Reduced Gcm1 Expression on Trophoblast Morphology, Fetoplacental Vascularity, and Pregnancy Outcomes in Mice

Preeclampsia is a life-threatening disorder characterized by maternal gestational hypertension and proteinuria that results from placental dysfunction. Placental abnormalities include abnormal syncytiotrophoblast and a 50% reduction in placental expression of the transcription factor Gcm1. In mice, homozygous deletion of Gcm1 prevents syncytiotrophoblast differentiation and is embryonic lethal. We used heterozygous Gcm1 mutants (Gcm1(+/-)) to test the hypothesis that hypomorphic expression of placental Gcm1 causes defective syncytiotrophoblast differentiation and maternal and placental phenotypes that resemble preeclampsia. We mated wild-type female mice with Gcm1(+/-) fathers to obtain wild-type mothers carrying ≈50% Gcm1(+/-) conceptuses. Gcm1(+/-) placentas had syncytiotrophoblast abnormalities including reduced gene expression of Gcm1-regulated SynB, elevated expression of sFlt1, a thickened interhemal membrane separating maternal and fetal circulations, and electron microscopic evidence in syncytiotrophoblast of necrosis and impaired maternal-fetal transfer. Fetoplacental vascularity was quantified by histomorphometry and microcomputed tomography imaging. In Gcm1(+/-), it was ≈30% greater than wild-type littermates, whereas placental vascular endothelial growth factor A (Vegfa) expression and fetal and placental weights did not differ. Wild-type mothers carrying Gcm1(+/-) conceptuses developed late gestational hypertension (118±2 versus 109.6±0.7 mm Hg in controls; P<0.05). We next correlated fetoplacental vascularity with placental Gcm1 expression in human control and pathological pregnancies and found that, as in mice, fetoplacental vascularity increased when GCM1 protein expression decreased (R(2)=-0.45; P<0.05). These results support a role for reduced placental Gcm1 expression as a causative factor in defective syncytiotrophoblast differentiation and maternal and placental phenotypes in preeclampsia in humans.