Objective Bacteria have been identified in different regions of the placenta. Here, we tested the hypothesis that the maternal basal plate of the placenta harbors microbes which may be associated with adverse pregnancy outcomes. Study Design We performed a cross-sectional study of pregnancies from a single tertiary care hospital. Maternal medical and obstetric characteristics were obtained and pregnancies followed prospectively for outcomes and placental collection. After delivery, systematic random sampling of the placental basal plate was performed. Paraffin sections of basal plates were stained with four histological stains and scored for morphological evidence of bacteria. Results Of 195 total patients in the study, Gram positive and negative intracellular bacteria of diverse morphologies were documented in the basal plates of 27% of all placentas. 35% of the patients delivered preterm. No difference was noted between placental basal plates from preterm or term gestations. Intracellular bacteria were found in the placental basal plates of 54% spontaneous preterm deliveries before 28 weeks, and in 26% of term spontaneous deliveries (p=0.02). Intracellular bacteria were also documented in placentas without clinical or pathologic chorioamnionitis. Conclusions 27% of placentas demonstrated intracellular bacteria in the placental basal plate using morphological techniques. Thus, the maternal basal plate is a possible source of intrauterine colonization and placental pathological examination could include examination for bacteria in this important maternal fetal interface.

Vitamin D is a pleiotropic secosteroid hormone important for health and disease prevention. The actions of vitamin D are mediated by the vitamin D receptor that binds the active form of vitamin D [1,25(OH) 2 D] to induce both transcriptional and non-genomic responses. Vitamin D has well known classical functions in calcium uptake and bone metabolism, but more recent work highlights the importance of the nonclassical actions of vitamin D in a variety of cell types. These actions include modulation of the innate and adaptive immune systems and regulation of cell proliferation. Adequate vitamin D intake is essential for maternal and fetal health during pregnancy, and epidemiological data indicate that many pregnant women have sub-optimal vitamin D levels. Notably, vitamin D deficiency correlates with preeclampsia, gestational diabetes mellitus, and bacterial vaginosis, and an increased risk for C-section delivery. Recent work emphasizes the importance of nonclassical roles of vitamin D in pregnancy and the placenta. The placenta produces and responds to vitamin D where vitamin D functions as a modulator of implantation, cytokine production and the immune response to infection. We describe vitamin D metabolism and the cellular responses to vitamin D, and then summarize the role of vitamin D in placental trophoblast, pregnancy and the fetus.

Prostaglandins (PGs) have been recently proven essential for parturition in mice. To dissect the contributions of the two cyclooxygenase (COX) isoforms to the synthesis of PGs during pregnancy, we have characterized the parturition phenotype of COX-1-deficient mice. We find that mice with targeted disruption of the COX-1 gene have delayed parturition resulting in neonatal death. Results of matings of COX-1-deficient females with COX-1 intact males, and blastocyst transfer of COX-1-deficient or -intact embryos into wild-type foster mothers, proved necessity and sufficiency of maternal COX-1 for the normal onset of labor. COX-1 expression is induced in gravid murine uterus and by in situ hybridization; this induction is localized to the decidua. Measurement of uterine PGs further confirmed that COX-1 accounted for the majority of PGF2␣ production. To evaluate the interaction of PGs with oxytocin during murine labor, we generated mice deficient in both oxytocin and COX-1. Surprisingly, the combined oxytocin and COX-1-deficient mice initiated labor at the normal time. COX-1-deficient mice demonstrated impaired luteolysis, as evidenced by elevated serum progesterone concentration and ovarian histology late in gestation, and delayed induction of uterine oxytocin receptors. In contrast, simultaneous oxytocin and COX-1 deficiency restored the normal onset of labor by allowing luteolysis in the absence of elevated PGF2␣ production. These findings demonstrate that COX-1 is essential for normal labor in the mouse, with a critical function being to overcome the luteotrophic action of oxytocin in late gestation.

Intrauterine growth restriction (IUGR) is a failure to achieve the growth potential of a fetus that is promised by the genetic constitution and environmental influences endogenous to the pregnancy. Optimal placental development and the ability of the placenta to compensate for stimulus-induced injury are central in promotion of normal fetal growth. In this review, we will overview placental development with a focus on how villous structure relates to function. We will also describe the differentiation and turnover of villous trophoblast while highlighting selected features of microscopic placental injury. Histopathological studies of the placenta in IUGR indicate that abnormalities of the maternal spiral arterioles, dysregulated villous vasculogenesis, and abundant fibrin deposition are characteristic of the injuries associated with this condition. We identify selected insults, including oxidative stress and complement activation, and key pathways that regulate apoptosis in villous trophoblast, including increased p53 activity, altered translation of AKT and mTOR proteins, and the stress response of the endoplasmic reticulum. We surmise that trophoblast dysregulation at a subcellular level and loss of functional mass of villous trophoblast via cell death pathways are key contributors to the suboptimal placental performance that yields IUGR. We predict that a better understanding of placental dysfunction in IUGR will lead to targeted therapeutic options for this important clinical condition.

Acting through degradation of target mRNA or inhibition of translation, microRNAs (miRNAs) regulate development, differentiation, and cellular response to diverse cues. We analyzed changes in miRNA expression in human placental trophoblasts exposed to hypoxia, which may result from hypoperfusion and placental injury. Using an miRNA microarray screen, confirmed by Northern blot analysis, we defined a set of seven miRNAs (miR-93, miR-205, miR-224, miR-335, miR-424, miR-451, and miR-491) that are differentially regulated in primary trophoblasts exposed to hypoxia. We combined in silico prediction of miRNA targets with gene expression profiling data to identify a series of potential targets for the miRNAs, which were further analyzed using luciferase reporter assays. Among experimentally confirmed targets, we found that the transcriptional coactivator MED1, which plays an important role in placental development, is a target for miR-205. Using gain- and loss-of-function assays, we confirmed that miR-205 interacts with a specific target in the 3'-UTR sequence of MED1 and silences MED1 expression in human trophoblasts exposed to hypoxia, suggesting that miR-205 plays a role in trophoblast injury.

Preeclampsia and fetal growth restriction are associated with placental hypoperfusion and villous hypoxia. The villous response to this environment includes diminished trophoblast differentiation and enhanced apoptosis. We tested the hypothesis that hypoxia induces apoptosis in cultured trophoblasts, and that epidermal growth factor (EGF), an enhancer of trophoblast differentiation, diminishes hypoxia-induced apoptosis. Trophoblasts isolated from placentas of term-uncomplicated human pregnancies were cultured up to 72 h in standard (PO(2) = 120 mm Hg) or hypoxic (PO(2) <15 mm Hg) conditions. Exposure to hypoxia for 24 h markedly enhanced trophoblast apoptosis as determined by DNA laddering, internucleosomal in situ DNA fragmentation, and histomorphology, as well as by the reversibility of the apoptotic process with a caspase inhibitor. Apoptosis was accompanied by increased expression of p53 and Bax and decreased expression of Bcl-2. Addition of EGF to cultured trophoblasts or exposure of more differentiated trophoblasts to hypoxia significantly lowered the level of apoptosis. We conclude that hypoxia enhances apoptosis in cultured trophoblasts by a mechanism that involves an increase in p53 and Bax expression. EGF and enhancement of cell differentiation protect against hypoxic-induced apoptosis.

The placenta is susceptible to diverse insults during human pregnancy. The expression of the protein N-myc down-regulated gene 1 (NDRG1) is regulated during cell proliferation, differentiation, and in response to stress. Nevertheless, the function of this protein in humans remains unknown. We tested the hypothesis that NDRG1 is up-regulated in hypoxic primary human trophoblasts and that NDRG1 modulates trophoblast response to hypoxia. We initially demonstrated that the expression of NDRG1 is enhanced in primary human trophoblasts exposed to hypoxia. Importantly, we found a similar increase in NDRG1 expression in placental samples derived from either singleton gestations complicated by intrauterine growth restriction or from dizygotic twin gestation where one twin exhibited growth restriction. Having established efficient lentivirus-mediated transfection of primary human trophoblasts, we overexpressed NDRG1 in trophoblasts, which resulted in enhanced trophoblast differentiation. In contrast, lentivirus-driven short interfering RNA-mediated silencing of NDRG1 diminished trophoblast viability and differentiation. Consistent with these results, NDRG1 reduced the expression level of p53 in trophoblasts cultured in standard or hypoxic conditions. Furthermore, NDRG1 expression was regulated by the activity of SIRT1 (Sir2-like protein 1), which promotes cell survival. Together, our data indicate that NDRG1 interacts with SIRT1/p53 signaling to attenuate hypoxic injury in human trophoblasts.The trophoblasts at the surface of human placental villi play a pivotal role in gas exchange, nutrition, waste removal, endocrine function, and immunological support for the developing fetus. Trophoblast invasion and early placental development occur in an environment of relative hypoxia (1, 2). Under these conditions hypoxia promotes invasion and angiogenesis (3) and is associated with up-regulation of vascular endothelial growth factor expression and down-regulation of placenta growth factor (4, 5). Trophoblast hypoxia later in pregnancy commonly stems from placental hypoperfusion, vasoconstriction, maternal systemic disease, high altitude, or smoking and may result in hypoxic injury to the placenta and consequently intrauterine growth restriction (IUGR) 2 with its consequences (6).Using high density oligonucleotide microarrays we have previously examined differences in gene expression between placental tissues from pregnancies complicated by IUGR versus matched normal placental tissues as well as from trophoblasts cultured under hypoxic or standard culture conditions (7,8). Combining these paradigms, we characterized a set of hypoxic trophoblast signature transcripts (8). Among these transcripts we consistently identified up-regulation of NDRG1 (N-myc down-regulated gene 1) transcript in hypoxic trophoblasts compared with cells cultured in standard conditions (8).3 NDRG1 (also called RTP, Drg1, Cap 43, rit42, TDD5, Ndr1, and PROXY-1) is a 394-amino acid protein expressed in both the cytoplasm and nucleus (9 -16) and implicated in c...

Objective To test the hypothesis that a combination of PP13, PAPP-A and first-trimester uterine artery Doppler would improve the prediction of preeclampsia. Methods This is a prospective cohort study of pregnant women followed from the first-trimester to delivery. PP13 and PAPPA were determined by immunoassay of maternal serum at 11 – 14 weeks’, when uterine artery Doppler measurements were assessed. Cases identified with any form of preeclampsiawere compared with a control group without preeclampsia. The sensitivity of each marker or their combinations in predicting preeclampsia for different fixed false positive rates was calculated from the ROC curves. Results Forty two women were diagnosed with preeclampsia and 410 women with pregnancies not complicated by preeclampsia were used as controls. For a fixed false positive rate (FPR) of 20%, PP13, PAPP-A and mean uterine artery pulsatility index identified 49%, 58% and 62% respectively, of women who developed any form of preeclampsia. PP13 was best in predicting early onset preeclampsia with a sensitivity of 79% at a 20% FPR.Combinations of the three first trimester assessments did not improve the prediction of preeclampsia in later pregnancy. Conclusion First-trimester PP13, PAPP-A and uterine artery PI are reasonable, individual predictors of women at risk to develop preeclampsia. Combinations of these assessments do not further improve the prediction of preeclampsia