New Insights on the Biomechanics of the Fetal Membrane.

During pregnancy, the Fetal Membrane (FM) is subjected to mechanical stretching that may result in preterm labor. The structural integrity of the FM is maintained by its collagenous layer. Disconnection and reconnection of molecular bonds between collagen fibrils is the fundamental process that governs the irreversible mechanical and supramolecular changes in the FM. At a critical threshold strain, bundling and alignment of collagen fibrils alter the super-molecular structure of the collagenous layer. Recent studies indicate that these changes are associated with inflammation and/or expression of specific proteins that are known to be related to uterine contractions and labor. The potential healing of stretching-induced damages in the FM by mediators involved in mechano-transduction is discussed.

Amniotic fluid soluble CD93 is elevated in the presence of intra-amniotic inflammation in preterm prelabor rupture of the fetal membranes.

OBJECTIVE: To determine the soluble form of CD93 (sCD93) concentration in amniotic fluid from pregnancies complicated by preterm prelabor rupture of membranes (PPROM) based on the presence of microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation. METHODS: A total of 144 women with a singleton pregnancy complicated by PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. MIAC was determined by the combination of cultivation and non-cultivation techniques. Intra-amniotic inflammation was characterized as a concentration of interleukin-6 3,000 pg/mL in amniotic fluid. Women were categorized in the following groups: i) intra-amniotic infection (both MIAC and intra-amniotic inflammation), ii) sterile intra-amniotic inflammation (intra-amniotic inflammation per se), iii) colonization of the amniotic cavity (MIAC per se), and iv) negative amniotic fluid (without both MIAC and intra-amniotic inflammation). Levels of sCD93 in amniotic fluid were assessed by ELISA. RESULTS: A difference in the levels of sCD93 in amniotic fluid was found among the groups of women with intra-amniotic infection, sterile intra-amniotic inflammation, colonization of the amniotic cavity, and negative amniotic fluid (intra-amniotic infection: median 22.3 ng/mL, sterile intra-amniotic inflammation: median 21.0 ng/mL, colonization of the amniotic cavity: 8.7 ng/mL, negative: median 8.7 ng/mL; P < 0.0001). CONCLUSIONS: Intra-amniotic inflammation in PPROM, irrespectively of the presence or absence of MIAC, is associated with the elevation of the level of sCD93 in amniotic fluid.

Expression of CYP450 enzymes in human fetal membranes and its implications in xenobiotic metabolism during pregnancy.

BACKGROUND: Environmental exposure to toxicants is a major risk factor for spontaneous preterm birth (PTB, <37 weeks). Toxicants and drugs administered to patients are metabolized primarily by the cytochrome P450 (CYP450) system. Along with the adult and fetal liver, the placenta, a critical feto-maternal interface organ, expresses CYP450 enzymes that metabolize these xenobiotics. However, the contribution of the fetal membranes, another tissue of the feto-maternal interface, to the expression of CYP450 enzymes and the detoxification of xenobiotics remains unknown. AIMS: This study characterized CYP450 expression and determined the functional activity of CYP450 enzymes in fetal membranes. MAIN METHODS: RNA sequencing (RNA-Seq) of placental and fetal membrane tissues and cells was done. Differential expressions of CYP450 genes were compared and validated via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) between the two tissues. The functional activity of major CYP450 enzymes was determined using a fluorophore-based enzymatic assay in the presence and absence of their corresponding inhibitors. KEY FINDINGS: With the exception of genes that regulate cholesterol metabolism, the expression profile of CYP450 genes was similar between placental and fetal membranes tissues/cells. RT-qPCR analysis confirmed these findings with significant levels of mRNA for major CYP450 genes being detectable in amnion epithelial cells (AECs) and chorion trophoblasts cells (CTCs). Biochemical analyses revealed significant CYP450 enzymatic activities that were sensitive to specific inhibitors for both AECs and CTCs, suggesting that the genes were expressed as functional enzymes. SIGNIFICANCE: This is the first study to determine global expression of CYP450 enzymes in fetal membranes which may play a role in xenobiotic metabolism during pregnancy. Given that many women are exposed to environmental toxins or require medications during pregnancy, a better understanding of their role in metabolism is required to develop safer therapeutics and prevent adverse outcomes.

Transcriptome changes in maternal peripheral blood during term parturition mimic perturbations preceding spontaneous preterm birth†.

The complex physiologic process of parturition includes the onset of labor, which requires the orchestrated stimulation of a common pathway involving uterine contractility, cervical ripening, and chorioamniotic membrane activation. However, the labor-specific processes taking place in these tissues have limited use as predictive biomarkers unless they can be probed in non-invasive samples, such as the peripheral blood. Herein, we utilized a transcriptomic dataset to assess labor-specific changes in the peripheral blood of women who delivered at term. We identified a set of genes that were differentially expressed with labor and enriched for immunological processes, and these gene expression changes were strongly correlated with results from prior studies, providing in silico validation of our findings. We then identified significant correlations between labor-specific transcriptomic changes in the maternal circulation and those detected in the chorioamniotic membranes, myometrium, and cervix of women at term, demonstrating that tissue-specific labor signatures are partly mirrored in the peripheral blood. Finally, we demonstrated a significant overlap between the peripheral blood transcriptomic changes in term parturition and those observed in asymptomatic women, prior to the diagnosis of preterm prelabor rupture of the membranes, who ultimately delivered preterm. Collectively, we provide evidence that the normal process of labor at term is characterized by a unique immunological expression signature, which may serve as a useful tool for assessing labor status and for potentially identifying women at risk for preterm birth.

Cell-Free DNA Release by Mouse Fetal Membranes.

INTRODUCTION: Cell-free "fetal" DNA is released from the placenta. Because the fetal membranes also arise from the trophectoderm layer of the blastocyst, these studies sought to test the hypothesis that the membranes also release cell-free DNA (cfDNA). METHODS: Fetal membranes were harvested from pregnant CD-1 mice and cultured in 12-well plates containing media alone or with staurosporine and thapsigargin (apoptosis stimulators), Q-VD-OPh (caspase inhibitor), Trolox (vitamin E analog), and lipopolysaccharide and tumor necrosis factor α (TNFα; inflammatory mediators). The cfDNA in the media was extracted, quantified, and normalized for tissue weight. Media was used for a lactate dehydrogenase (LDH) assay. Membrane homogenates were used to assess activated caspase levels and the expression of DNA fragmentation factor B (DFFB) and BAX proteins. 5-Methylcytosine was assessed using a 5-mC DNA enzyme-linked immunosorbent assay. The cfDNA was used to stimulate interleukin 6 (IL6) release by J774A.1 mouse macrophage cells. RESULTS: Increased cfDNA release at 6 and 21 hours occurred in parallel with increasing LDH levels. The cfDNA concentrations were significantly suppressed by Q-VD-OPh and Trolox and increased by thapsigargin and TNFα. Increased caspase activity was suppressed by Q-VD-OPh and increased by TNFα, thapsigargin, and staurosporine. The expression of BAX and DFFB proteins significantly increased by 21 hours. 5-Methylcytosine levels were significantly lower in fetal membranes and placentas and below detectable in the cfDNA released by the explants. The cfDNA-stimulated IL6 release by macrophage cells was suppressed by chloroquine, a Toll-like receptor 9 (TLR9) inhibitor. CONCLUSIONS: These studies have confirmed cfDNA release by the mouse fetal membranes; cfDNA was markedly hypomethylated and a robust stimulator of TLR9.

Immunohistochemical demonstration of RECK protein and interleukin-6 in fetal membranes from singleton pregnancies with late preterm delivery, intact membranes and histological chorioamnionitis.

We investigated whether chorioamnionitis affects immunohistochemical demonstration of RECK protein and interleukin-6 (IL-6) expression in fetal placental membranes following late preterm delivery with intact membranes. Fetal membranes of 28 women with single pregnancy, preterm delivery and histologically documented chorioamnionitis at gestational age 34-366/7 weeks constituted the chorioamnionitis study group. The control group consisted of 28 fetal membranes from women with preterm deliveries at the same gestational age without histological chorioamnionitis. Immunohistochemistry was performed using monoclonal antibodies against RECK protein and IL-6. We found a statistically significant difference in RECK expression between the chorioamnionitis and control groups; however, we found no difference in IL-6 expression between the groups. We demonstrated that RECK expression is down-regulated in fetal membranes from pregnancies with spontaneous late preterm birth and intact membranes, which suggests its role in preterm parturition. Equal expression of IL-6 in fetal membranes of pregnancies with and without histological chorioamnionitis is an intriguing and unexpected observation that requires further investigation.

Aquaporin 1 gene deletion affects the amniotic fluid volume and composition as well as the expression of other aquaporin water channels in placenta and fetal membranes.

OBJECTIVE: To explore the role of aquaporin 1 (AQP1) in regulation of amniotic fluid volume and composition. To investigate the effects of AQP1 gene knockout on expression of other aquaporin water channels (AQP3, AQP8 and AQP9) in placentas and fetal membranes. METHODS: Mice were sacrificed at 9.5, 13.5 and 16.5 gestational day (GD). Amniotic fluid volume, osmolality and composition, fetal membranes, placental and fetal weights as well as placenta areas were recorded in Aqp1 homozygote conceptus group, heterozygote conceptus group and wild-type group, respectively. The expression of AQP1, AQP3, AQP8 and AQP9 mRNA and protein in placenta and fetal membranes were examined by quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting. RESULTS: Aqp1 homozygote conceptus had a greater volume of amniotic fluid, lower osmolality and calcium concentration than their wild-type counterparts at 16.5 GD. There was no significant difference in expression of AQP1, AQP3, AQP8 and AQP9 in placentas among three groups. While expression of AQP8 was increased at 13.5 and 16.5 GD in fetal membranes, the expression of AQP9 was significantly decreased in fetal membranes in Aqp1 homozygote group compared with Aqp1 heterozygote and wild-type groups. CONCLUSION: AQP1 may play an important role in the homeostasis of maternal-fetal fluid at late gestation days. The mechanism of mutual compensation among AQPs gene needs further investigation.

Tissuepatch is biocompatible and seals iatrogenic membrane defects in a rabbit model.

OBJECTIVE: To evaluate novel sealing techniques for their biocompatibility and sealing capacity of iatrogenic fetal membrane defects in a pregnant rabbit model. METHOD: At day 23 of gestation (term = d31), a standardized fetoscopy was performed through a 14G cannula. The resulting fetal membrane defect was closed with condensed collagen, collagen with fibrinogen, Tissuepatch, Duraseal, or a conventional collagen plug (Lyostypt) as reference. At d30, the fetuses were harvested and full thickness fetal membrane samples were analyzed. The study consisted of 2 consecutive parts: (1) biocompatibility testing by fetal survival, apoptosis, and infiltration of polymorphonuclear cells in the membranes and (2) the efficacy to seal fetal membrane defects. RESULTS: Three sealants (collagen with fibrinogen, Duraseal, or Lyostypt) were associated with a higher fetal mortality compared to control unmanipulated littermates and hence were excluded from further analysis. Tissuepatch was biocompatible, and amniotic fluid levels were comparable to those of control untouched littermates. Compared to the condensed collagen, Tissuepatch was also easier in surgical handling and induced limited cell proliferation. CONCLUSION: Tissuepatch had the best biocompatibility and efficacy in sealing an iatrogenic fetal membrane defect in the pregnant rabbit compared to other readily available sealants.

Systemic and placental α-klotho: Effects of preeclampsia in the last trimester of gestation.

INTRODUCTION: α-klotho is an anti-aging protein, potentially important in preeclampsia (PE). Produced by kidney, brain and placenta, and by mRNA splicing is both a full-length membrane-bound and a truncated soluble protein in the circulation. The membrane-bound protein is an obligate co-receptor for fibroblast growth factor 23 (FGF23) and its action on receptor (FGFR), but ADAM proteinases also cause its shedding. The aims of this study were to investigate levels of maternal plasma, placental, and fetal membrane α-Klotho and their association with placental accelerated villous maturation (AVM) in PE. In addition, placental and membrane levels of ADAM17 and FGFR were measured in the same patients. METHODS: Maternal blood, placenta and fetal membranes from 61 women (31 with PE and 30 controls) between 32 and 40 weeks gestation were collected. Plasma α-klotho was measured by ELISA, and quantitative immunohistochemistry used for α-klotho, ADAM17 and FGFR1 in tissues. Placental AVM was histologically assessed. RESULTS: Maternal plasma levels of α-Klotho were higher in PE compared to controls (p = 0.01) and patients with the highest levels had significantly less AVM (p = 0.03). α-Klotho, ADAM17, and FGFR were all present in syncytiotrophoblast and cytotrophoblast of membranes. Between 32 and 40 weeks gestation, all placental levels decreased in controls respectively (p = 0.04, p = 0.004, p = 0.05), but not in PE. Fetal membrane levels were unchanged. DISCUSSION: Maternal plasma α-Klotho was increased in PE and its levels associated with reduced placental AVM. Changes in placental α-Klotho, ADAM17, and FGFR suggest their involvement in the pathophysiology of PE.

Characterization of irreversible physio-mechanical processes in stretched fetal membranes.

We perform bulge tests on live fetal membrane (FM) tissues that simulate the mechanical conditions prior to contractions. Experimental results reveal an irreversible mechanical behavior that appears during loading and is significantly different than the mechanical behavior that appears during unloading or in subsequent loading cycles. The irreversible behavior results in a residual strain that does not recover upon unloading and remains the same for at least 1h after the FM is unloaded. Surprisingly, the irreversible behavior demonstrates a linear stress-strain relation. We introduce a new model for the mechanical response of collagen tissues, which accounts for the irreversible deformation and provides predictions in agreement with our experimental results. The basic assumption of the model is that the constitutive stress-strain relationship of individual elements that compose the collagen fibers has a plateau segment during which an irreversible transformation/deformation occurs. Fittings of calculated and measured stress-strain curves reveal a well-defined single-value property of collagenous tissues, which is related to the threshold strain εth for irreversible transformation. Further discussion of several physio-mechanical processes that can induce irreversible behavior indicate that the most probable process, which is in agreement with our results for εth, is a phase transformation of collagen molecules from an α-helix to a ß-sheet structure. A phase transformation is a manifestation of a significant change in the molecular structure of the collagen tissues that can alter connections with surrounding molecules and may lead to critical biological changes, e.g., an initiation of labor. STATEMENT OF SIGNIFICANCE: This study is driven by the hypothesis that pre-contraction mechanical stretch of the fetal membrane (FM) can lead to a change in the microstructure of the FM, which in turn induces a critical biological (hormonal) change that leads to the initiation of labor. We present mechanical characterizations of live FM tissues that reveal a significant irreversible process and a new model for the mechanical response of collagen tissues, which accounts for this process. Fittings of calculated and measured results reveal a well-defined single-value property of collagenous tissues, which is related to the threshold strain for irreversible transformation. Further discussion indicates that the irreversible deformation is induced by a phase transformation of collagen molecules that can lead to critical biological changes.

Placenta expresses anti-Müllerian hormone and its receptor: Sex-related difference in fetal membranes.

INTRODUCTION: Anti-Müllerian hormone (AMH) is a member of the transforming growth factor-ß superfamily, playing a role in sexual differentiation and recruitment. Since a correlation exists between AMH serum levels in cord blood and fetal sex, the present study aimed to identify mRNA and protein expression of AMH and AMHRII in placenta and fetal membranes according to fetal sex. METHODS: Placenta and fetal membranes samples (n = 40) were collected from women with singleton uncomplicated pregnancies at term. Identification of AMH protein in placenta and fetal membranes was carried out by immunohistochemistry and AMH and AMHRII protein localization by immunofluorescence, while mRNA expression was assessed by quantitative real-time PCR. RESULT: AMH and AMHRII mRNAs were expressed by placenta and fetal membranes at term, without any significant difference between males and females. Placental immunostaining showed a syncytial localization of AMH without sex-related differences; while fetal membranes immunostaining was significantly more intense in male than in female fetuses (p < 0,01). Immunofluorescence showed an intense co-localization of AMH and AMHRII in placenta and fetal membranes. DISCUSSION: The present study for the first time demonstrated that human placenta and fetal membranes expresses and co-localizes AMH and AMHRII. Although no sex-related difference was found for the mRNA expression both in placenta and fetal membranes, a most intense staining for AMH in male fetal membranes supports AMH as a gender specific hormone.

Extract of fetal membrane would inhibit thrombosis and hemolysis.

The innermost layer of fetal membranes is amnion which has anti-adhesive, anti-inflammation and viscoelastic properties, as well as low immunogenicity. Amniotic membrane has been employed in variety of clinical fields as a natural biomaterial. Amniotic epithelial cells possess stem cell characteristics and capability to differentiate into endothelial cells. The basement membrane of amnion is an extracellular matrix enriched scaffold to support adhesion of endothelial cells. The matrix of amniotic membrane contains two kinds of glycosaminoglycans including perlecan (a heparan sulfate proteoglycan) and hyaluronic acid which both inhibit blood coagulation. Moreover, the other ingredients of amniotic membrane such as pigment-epithelium derived factor (PEDF), IL-10, MMP-9 inhibit platelet aggregation. Based on some biochemical and biomechanical evidences, we hypothesized in this paper that amniotic membrane could prevent thrombosis and hemolysis; therefore, has the capability to be applied in blood contacting devices and implants.

Dynamic proteomic profiles of in vivo- and in vitro-produced mouse postimplantation extraembryonic tissues and placentas.

As the interface between the mother and the developing fetus, the placenta is believed to play an important role in assisted reproductive technology (ART)-induced aberrant intrauterine and postnatal development. However, the mechanisms underlying aberrant placentation remain unclear, especially during extraembryonic tissue development and early stages of placental formation. Using a mouse model, this investigation provides the first comparative proteomic analysis of in vivo (IVO) and in vitro-produced (IVP) extraembryonic tissues and placentas after IVO fertilization and development, or in vitro fertilization and culture, respectively. We identified 165 and 178 differentially expressed proteins (DEPs) between IVO and IVP extraembryonic tissues and placentas on Embryonic Day 7.5 (E7.5) and E10.5, respectively. Many DEPs were functionally associated with genetic information processing, such as impaired de novo DNA methylation, as well as posttranscriptional, translational and posttranslational dysregulation. These novel findings were further confirmed by global hypomethylation, and a lower level of correlation was found between the transcriptome and proteome in the IVP groups. In addition, numerous DEPs were involved in energy and amino acid metabolism, cytoskeleton organization and transport, and vasculogenesis and angiogenesis. These disturbed processes and pathways are likely to be associated with embryonic intrauterine growth restriction, an enlarged placenta, and impaired labyrinth morphogenesis. This study provides a direct and comprehensive reference for the further exploration of the placental mechanisms that underlie ART-induced developmental aberrations.

Leukotriene receptor antagonist as a novel tocolytic in an in vitro model of human uterine contractility.

OBJECTIVE: This study analyzed the ability of montelukast, a cysteinyl-leukotrienes receptor antagonist and anti-inflammatory agent, to produce a consistent tocolytic effect alone or in combination with nifedipine, a calcium (Ca(2+)) channel blocker currently used in clinical practice. STUDY DESIGN: Uterine biopsies were obtained from consenting women undergoing elective cesarean sections at term (n=20). Myometrial microsomal fractions were analyzed by immunoblotting to quantify relative cysteinyl leukotrienes receptor 1 (CysLTR1) levels. Isometric tension measurements were performed in vitro on human myometrial strips (n=120) in isolated organ baths in order to establish concentration-response curves to montelukast and to quantify changes in Ca(2+) sensitivity on ß-escin permeabilized tissues. RESULTS: Immunodetection analysis revealed the presence of CysLTR1 receptor in uterine tissues, fetal membranes and placenta. A significant increase in area under the curve (AUC) was quantified following the addition of leukotriene D4 (LTD4) (0.01-0.3 µM), an end-product of the lipoxygenase pathway. Conversely, addition of montelukast produced a significant tocolytic effect by decreasing the frequency and AUC (IC50=1 µM). Moreover, addition of montelukast also resulted in a reduced Ca(2+) sensitivity as compared to control tissues (EC50 values of 654 and 403 nM; p=0.02 at pCa 6), while an additive effect was observed in combination with 0.1 nM nifedipine (p=0.004). CONCLUSION: This original study demonstrates the potency of montelukast as a tocolytic agent in an in vitro human uterine model. Montelukast, in combination with nifedipine, could represent a therapeutic approach to reduce inflammation associated with prematurity while facilitating the inhibition of preterm labor.

FOXM1 is lower in human fetal membranes after spontaneous preterm labour and delivery.

Spontaneous preterm birth is usually associated with infection, inflammation or both. Forkhead box (FOX) M1 (FOXM1), a member of the FOX family of transcription factors, has been associated with inflammation. The aim of this study was to determine whether FOXM1 regulates the expression and release of pro-labour mediators in human gestational tissues. FOXM1 mRNA and protein expression were determined in fetal membranes from women at (1) preterm no labour: Caesarean section with no labour and (2) preterm labour: after spontaneous labour and delivery. Primary amnion cells were utilised to investigate the effect of small interfering RNA (siRNA)-mediated gene silencing of FOXM1 on pro-labour mediators. Spontaneous preterm labour decreased FOXM1 gene and nuclear protein expression. FOXM1 silencing in primary amnion cells increased interleukin (IL)-1ß-induced pro-inflammatory cytokines (IL-6 and IL-8 mRNA expression and secretion), cyclooxygenase (COX)-2 expression and subsequent prostaglandin (PG)E2 and PGF2α release as well as gene expression and secretion of the matrix-degrading enzyme matrix metalloproteinase 9 (MMP-9). In conclusion, spontaneous preterm labour is associated with decreased FOXM1 expression in fetal membranes.

Second harmonic generation microscopy of fetal membranes under deformation: normal and altered morphology.

INTRODUCTION: Insight into the microstructure of fetal membrane and its response to deformation is important for understanding causes of preterm premature rupture of the membrane. However, the microstructure of fetal membranes under deformation has not been visualized yet. Second harmonic generation microscopy, combined with an in-situ stretching device, can provide this valuable information. METHODS: Eight fetal membranes were marked over the cervix with methylene blue during elective caesarean section. One sample per membrane of reflected tissue, between the placenta and the cervical region, was cyclically stretched with a custom built inflation device. Samples were mounted on an in-situ stretching device and imaged with a multiphoton microscope at different deformation levels. Microstructural parameters such as thickness and collagen orientation were determined. Image entropy was evaluated for the spongy layer. RESULTS: The spongy layer consistently shows an altered collagen structure in the cervical and cycled tissue compared with the reflected membrane, corresponding to a significantly higher image entropy. An increased thickness of collagenous layers was found in cervical and stretched samples in comparison to the reflected tissue. Significant collagen fibre alignment was found to occur already at moderate deformation in all samples. CONCLUSIONS: For the first time, second harmonic generation microscopy has been used to visualize the microstructure of fetal membranes. Repeated mechanical loading was shown to affect the integrity of the amnion-chorion interface which might indicate an increased risk of premature rupture of fetal membrane. Moreover, mechanical loading might contribute to morphological alterations of the fetal membrane over the cervical region.

Disposition of desfuroylceftiofur acetamide in serum, placental tissue, fetal fluids, and fetal tissues after administration of ceftiofur crystalline free acid (CCFA) to pony mares with placentitis.

The objective of this study was to determine the pharmacokinetics of CCFA in mares with placentitis and evaluate the disposition of the drug in fetal fluids, fetal membranes, colostrum, and serum of foals. A secondary objective was to obtain pilot data regarding the efficacy of CCFA for improving foal survival in mares with placentitis. Twelve pregnant pony mares were enrolled in the study, inoculated with Streptococcus zooepidemicus, intracervically and assigned to one of three groups: CEFT (n = 3; administered CCFA only; 6.6 mg/kg, i.m., q96h); COMBO (n = 6; administered combination therapy of CCFA, altrenogest, and pentoxifylline); UNTREAT (n = 3, no treatment). Treatment was initiated at the onset of clinical signs. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur metabolites, were measured using high-performance liquid chromatography. Maximum and minimum serum concentrations of DCA at steady state in treated mares were 2.40±0.40 µg/mL and 1.06±0.29 µg/mL, respectively. Concentration of DCA in colostrum was 1.51±0.60 µg/mL. DCA concentrations in placenta and fetal tissues were very low (median = 0.03 µg/mL) and below the minimum inhibitory concentration of relevant pathogens. DCA was not detected in amniotic fluid or foal serum. Treatment did not appear to improve foal survival (CEFT: 0/3; COMBO: 2/6; UNTREAT: 2/3). Bacteria were recovered from the uterus of most mares postpartum and from blood cultures of most foals regardless of treatment.

Immunohistochemical detection of meconium in the fetal membrane, placenta and umbilical cord.

OBJECTIVE: To develop the immunohistochemistry specific for meconium in the placenta, fetal membrane and umbilical cord. STUDY DESIGN: We previously reported the specific presence of zinc coproporphyrin I (ZnCP-I) in human meconium and demonstrated the possible diagnostic use of an elevation in maternal plasma ZnCP-I levels in cases of amniotic fluid embolism. In this study, we developed a new specific monoclonal antibody for ZnCP-I and applied it to the immunostaining of meconium in the placenta, fetal membrane, and umbilical cord. RESULTS: Immunoreactivity of ZnCP-I clearly and specifically identified meconium in the placenta, fetal membrane, and umbilical cord. It was especially useful in cases of severe chorioamnionitis to detect meconium in the macrophages surrounded by numerous neutrophils. In more than half of the cases, meconium was detected in clear amniotic fluid at delivery, suggesting previous exposure. CONCLUSIONS: Immunohistochemical detection of ZnCP-I is a highly sensitive histological diagnosis of meconium.

High-resolution imaging diagnosis of human fetal membrane by three-dimensional optical coherence tomography.

Microscopic chorionic pseudocyst (MCP) arising in the chorion leave of the human fetal membrane (FM) is a clinical precursor for preeclampsia which may progress to fatal medical conditions (e.g., abortion) if left untreated. To examine the utility of three-dimensional (3D) optical coherence tomography (OCT) for noninvasive delineation of the morphology of human fetal membranes and early clinical detection of MCP, 60 human FM specimens were acquired from 10 different subjects undergoing term cesarean delivery for an ex vivo feasibility study. Our results showed that OCT was able to identify the four-layer architectures of human FMs consisting of high-scattering decidua vera (DV, average thickness d(DV) ≈ 92±38 µm), low-scattering chorion and trophoblast (CT, d(CT) ≈ 150±67 µm), high-scattering subepithelial amnion (A, d(A) ≈ 95±36 µm), and low-scattering epithelium (E, d(E) ≈ 29±8 µm). Importantly, 3D OCT was able to instantaneously detect MCPs (low scattering due to edema, fluid buildup, vasodilatation) and track (staging) their thicknesses d(MCP) ranging from 24 to 615 µm. It was also shown that high-frequency ultrasound was able to compliment OCT for detecting more advanced thicker MCPs (e.g., d(MCP)>615 µm) because of its increased imaging depth.

[Biochemistry of fetal membranes rupture]. / Biochimie de la rupture des membranes fœtales.

Fetal membranes, amnion and chorion, line up the amniotic cavity and are essential for its integrity towards normal term of pregnancy. They consist of a pluristratified structure whose composition assures their cohesion and elasticity. They firstly function in retaining the fluctuant amniotic fluid in a half-rigid cavity. Their elastic limit depends on the organization of the extracellular matrix and firstly on the collagen type it contains. The compact layer of the amnion, responsible for the elastic limit, contains mainly type I collagen, organized in lattice; this allows elongation or spreading. Underneath, the spongy layer, principally of collagen III, is organized in a loose mesh, enriched in hydrated proteoglycans, which allows the absorption of the shocks and the sliding of the amnion on the chorion. The cascade of events leading to the membrane rupture displays: (i) membranes distension with elasticity loss, (ii) separation of the chorion from the amnion, (iii) chorion fracture, (iv) amnion distension which produces an hernia, (v) amnion rupture. The rupture mechanism was long thought to be a consequence of uterine contractions. However, the observation before labour of a zone of altered morphology, with biochemical variations (modifications of metalloprotease activity and of proteoglycans, apoptosis...) associated with focal physical weakness in the region overlying the cervix suggests programming of the rupture before parturition. A better understanding of the biochemical mechanisms of membranes rupture will provide new insights into how to anticipate and to intervene in the case of risk of premature rupture.