miR-146a-5p-mediated suppression on trophoblast cell progression and epithelial-mesenchymal transition in preeclampsia.

OBJECTIVE: This study aims to identify the effect of miR-146a-5p on trophoblast cell invasion as well as the mechanism in preeclampsia (PE). METHODS: Expression levels of miR-146a-5p and Wnt2 in preeclamptic and normal placentae were quantified. Trophoblast cells (HTR-8) were separately transfected with miR-146a-5p mimic, miR-146a-5p inhibitor, pcDNA3.1-Wnt2 or sh-Wnt2, and then the expression levels of miR-146a-5p, Wnt2, and epithelial-mesenchymal transition (EMT)-related proteins (Vimentin, N-cadherin and E-cadherin) were measured. Moreover, the proliferative, migratory and invasive capacities of trophoblast cells were detected, respectively. Dual luciferase reporter assay determined the binding of miR-146a-5p and Wnt2. RESULTS: Compared with normal placental tissues, the placentae from PE patients showed higher miR-146a-5p expression and lower Wnt2 expression. Transfection of miR-146a-5p inhibitor or pcDNA3.1-Wnt2 exerted pro-migratory and pro-invasive effects on HTR-8 cells and encouraged EMT in HTR-8 cells; transfection with miR-146a-5p mimic or sh-Wnt2 weakened the proliferative, migratory and invasive capacities as well as reduced EMT process of HTR-8 cells. Moreover, Wnt2 overexpression could partially counteract the suppressive effects of miR-146a-5p overexpression on the progression and EMT of HTR-8 cells. CONCLUSION: miR-146a-5p mediates trophoblast cell proliferation and invasion through regulating Wnt2 expression.

miR-146a-5p-mediated suppression on trophoblast cell progression and epithelial-mesenchymal transition in preeclampsia

OBJECTIVE: This study aims to identify the effect of miR-146a-5p on trophoblast cell invasion as well as the mechanism in preeclampsia (PE). METHODS: Expression levels of miR-146a-5p and Wnt2 in preeclamptic and normal placentae were quantified. Trophoblast cells (HTR-8) were separately transfected with miR-146a-5p mimic, miR-146a-5p inhibitor, pcDNA3.1-Wnt2 or sh-Wnt2, and then the expression levels of miR-146a-5p, Wnt2, and epithelial-mesenchymal transition (EMT)-related proteins (Vimentin, N-cadherin and E-cadherin) were measured. Moreover, the proliferative, migratory and invasive capacities of trophoblast cells were detected, respectively. Dual luciferase reporter assay determined the binding of miR-146a-5p and Wnt2. RESULTS: Compared with normal placental tissues, the placentae from PE patients showed higher miR-146a-5p expression and lower Wnt2 expression. Transfection of miR-146a-5p inhibitor or pcDNA3.1-Wnt2 exerted pro-migratory and pro-invasive effects on HTR-8 cells and encouraged EMT in HTR-8 cells; transfection with miR-146a-5p mimic or sh-Wnt2 weakened the proliferative, migratory and invasive capacities as well as reduced EMT process of HTR-8 cells. Moreover, Wnt2 overexpression could partially counteract the suppressive effects of miR-146a-5p overexpression on the progression and EMT of HTR-8 cells. CONCLUSION: miR-146a-5p mediates trophoblast cell proliferation and invasion through regulating Wnt2 expression.

Annexin A1/Formyl Peptide Receptor Pathway Controls Uterine Receptivity to the Blastocyst.

Embryo implantation into the uterine wall is a highly modulated, complex process. We previously demonstrated that Annexin A1 (AnxA1), which is a protein secreted by epithelial and inflammatory cells in the uterine microenvironment, controls embryo implantation in vivo. Here, we decipher the effects of recombinant AnxA1 in this phenomenon by using human trophoblast cell (BeWo) spheroids and uterine epithelial cells (Ishikawa; IK). AnxA1-treated IK cells demonstrated greater levels of spheroid adherence and upregulation of the tight junction molecules claudin-1 and zona occludens-1, as well as the glycoprotein mucin-1 (Muc-1). The latter effect of AnxA1 was not mediated through IL-6 secreted from IK cells, a known inducer of Muc-1 expression. Rather, these effects of AnxA1 involved activation of the formyl peptide receptors FPR1 and FPR2, as pharmacological blockade of FPR1 or FPR1/FPR2 abrogated such responses. The downstream actions of AnxA1 were mediated through the ERK1/2 phosphorylation pathway and F-actin polymerization in IK cells, as blockade of ERK1/2 phosphorylation reversed AnxA1-induced Muc-1 and claudin-1 expression. Moreover, FPR2 activation by AnxA1 induced vascular endothelial growth factor (VEGF) secretion by IK cells, and the supernatant of AnxA1-treated IK cells evoked angiogenesis in vitro. In conclusion, these data highlight the role of the AnxA1/FPR1/FPR2 pathway in uterine epithelial control of blastocyst implantation.

Interplay between neutrophils and trophoblast cells conditions trophoblast function and triggers vascular transformation signals.

Normal placentation entails highly regulated interactions of maternal leukocytes with vascular and trophoblast cells to favor vascular transformation. Neutrophil activation and neutrophil extracellular trap (NET) formation associate with poor placentation and severe pregnancy complications. To deepen into the mechanisms of trophoblast-neutrophil interaction, we explored the effects of NETs on trophoblast cell function and, conversely, whether trophoblast cell-derived factors condition neutrophils to favor angiogenesis and anti-inflammatory signals required for fetal growth. NETs isolated from activated neutrophils hindered trophoblast cell migration. Trophoblast conditioned media prevented the effect as well as the vasoactive intestinal peptide (VIP) known to regulate trophoblast and neutrophil function. On the other hand, factors released by trophoblast cells and VIP shaped neutrophils to a proangiogenic profile with increased vascular endothelial growth factor synthesis and increased capacity to promote vascular transformation. Results presented here provide novel clues to reconstruct the interaction of trophoblast cells and neutrophils in vivo during placentation in humans.

DNA Methylation of the Insulin-Like Growth Factor 2-Imprinted Gene in Trophoblast Cells of Elongated Bovine Embryo: Effects of the In Vitro Culture.

DNA methylation is an essential epigenetic mark for embryo development and can be susceptible to environment factors such as in vitro conditions. The aim of this study was to verify the effect of in vitro culture until Day (D) 14 of the development on the embryo size and DNA methylation pattern of the insulin-like growth factor 2 (IGF2)-imprinted gene. To achieve this, we produced bovine embryos completely in vivo, completely in vitro, and in vitro until D7 and then in vivo up to D14. The embryos produced in in vitro were smaller than those in other two groups (p = 0.024); no differences in embryo size were observed between genders. The in vitro embryos showed a higher level of DNA methylation in the IGF2 as compared with that in the completely in vivo-produced (IVV) embryos (p = 0.009). Furthermore, totally in vitro-produced male embryos showed higher levels of DNA methylation as compared with those observed for the totally IVV male embryos (p = 0.034). No differences were observed among genders for IGF2 DNA methylation. These results showed that the window between D7 and D14 is critical for embryo development and alterations in the environmental conditions during this period can impair DNA methylation establishment of important developmental imprinted genes. This study brings unprecedented data for bovine embryos regarding the impact of the environmental conditions during the posthatching development.

Osmotic stress induces apoptosis in extravillous trophoblast cells. Role of TRPV-1.

In different tissues hyperosmolarity induces cell differentiation. Nevertheless an exacerbated hyperosmolar stress alters the normal cellular development. The transient receptor potential vanilloid 1 (TRPV-1) is a non-selective cation channel that is activated by hyperosmolarity and participates in many cellular processes. TPRV-1 is expressed in human placenta at term. Here, we evaluated the expression of TRPV-1 in first trimester extravillous trophoblast cells and its participation in the survival of these cells exposed to hyperosmolar stress. Our results showed that hyperosmolar stress up-regulates the expression of TRPV-1 and induces the apoptosis in Swan 71 cells. In addition, the inhibition of TRPV-1 abrogates the apoptotic events.

The number of biopsied trophectoderm cells may affect pregnancy outcomes.

OBJECTIVE: To study if the number of trophectoderm (TE) biopsied cells has an impact on implantation rates. DESIGN: A retrospective cohort study in a single-center study. SETTING: In vitro fertilization center. PATIENTS: Patients who underwent PGT-A from January 2013 to March 2016. In total, 482 vitrified/warmed single embryo transfers were included. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Clinical pregnancies rate, implantation rate. RESULTS: Overall, clinical pregnancies per embryo transfer were higher when a regular TE were biopsied compared to larger size biopsy cells (66% (175/267) vs 53% (115/215) (p < 0.005) respectively). Pregnancy rates were also analyzed according to embryo morphology at the moment of embryo biopsy, when a good-quality embryo was transferred the clinical outcome was 75% (81/108) in group 1 and 61% (60/99) in group 2 (p < 0.05). Data was also stratified by age in patients ≤ 35 years and > 35 years. The clinical pregnancy was 67% (51/76) in women ≤ 35 years and 65% (124/191) in women > 35 years when a regular size biopsy was performed. These results significantly reduced when a larger size biopsy was performed 54% (49/91) and 53% (66/124), respectively (p < 0.05). Further investigation indicated that miscarriage rate was similar between these groups (4% (7/182) in group 1 and 5% (6/121) in group 2). CONCLUSIONS: These findings underscore that when a large amount of TE cells are biopsied, it may negatively affect implantation rates, but once implanted, the embryos have the same chance to miscarry or reach term.

The blocking of aquaporin-3 (AQP3) impairs extravillous trophoblast cell migration.

Several aquaporins (AQPs) are expressed in extravillous (EVT) and villous trophoblast cells. Among them, AQP3 is the most abundant AQP expressed in chorionic villi samples from first trimester, followed by AQP1 and AQP9. Although AQP3 expression persists in term placentas, it is significantly decreased in placentas from preeclamptic pregnancies. AQP3 is involved in the migration of different cell types, however its role in human placenta is still unknown. Here, we evaluated the role of AQP3 in the migration of EVT cells during early gestation. Our results showed that Swan 71 cells expressed AQP1, AQP3 and AQP9 but only the blocking of AQP3 by CuSO4 or the silencing of its expression by siRNA significantly attenuates EVT cell migration. Our work provides evidence that AQP3 is required for EVT cell migration and suggests that an altered expression of placental AQP3 may produce failures in placentation such as in preeclampsia.

The effect of oxidative stress induced by tert-butylhydroperoxide under distinct folic acid conditions: An in vitro study using cultured human trophoblast-derived cells.

Preeclampsia is a pregnancy disorder characterized by high maternal blood pressure, fetal growth restriction and intrauterine hypoxia. Folic acid is a vitamin required during pregnancy. In this work, we investigated the relationship between preeclampsia and the intake of distinct doses of folic acid during pregnancy. Considering that preeclampsia is associated with increased placental oxidative stress levels, we investigated the effect of oxidative stress induced by tert-butylhydroperoxide (TBH) in human trophoblast-derived cells cultured upon deficient/low, physiological and supra-physiological folic acid levels. The negative effect of TBH upon thiobarbituric acid reactive substances (TBARS), total, reduced and oxidized glutathione, cell viability, cell proliferation, culture growth and cell migration was more marked under folic acid excess. This study suggests more attention on the dose administered, and ultimately, on the overall folic acid levels during pregnancy, in the context of preeclampsia risk.

Lysophosphatidic acid-triggered pathways promote the acquisition of trophoblast endovascular phenotype in vitro.

Successful implantation and placentation requires that extravillous cytotrophoblast acquires an endovascular phenotype and remodels uterine spiral arteries. Defects in this mechanism correlate with severe obstetric complications as implantation failure and preeclampsia. Lysophosphatidic acid (LPA) participates in embryo implantation and contributes to vascular physiology in different biological systems. However, the role of LPA on trophoblast endovascular transformation has not been studied. Due to difficulties in studying human pregnancy in vivo, we adopted a pharmacological approach in vitro to investigate LPA action in various aspects of trophoblast endovascular response, such as the formation of endothelial capillary-like structures, migration, and proliferation. The HTR-8/SVneo cell line established from human first trimester cytotrophoblast was used to model the acquisition of the endovascular phenotype by the invading trophoblast. LPA increased HTR-8/SVneo tube formation, migration (wound healing assay and phalloidin staining) and proliferation (MTT assay). LPA G protein-coupled receptors, LPA1 and LPA3 , were expressed in HTR-8/SVneo. By using selective antagonists, we showed that enhanced tubulogenesis was mediated by LPA3 . In addition, cyclooxygenase-2 and inducible nitric oxide synthase pathways participated in LPA-stimulated tubulogenesis. Inducible nitric oxide synthase was activated downstream cyclooxygenase-2. Furthermore, prostaglandin E2 and a nitric oxide donor (SNAP) increased trophoblast tube formation in a concentration-dependent manner. Finally, we observed that cyclooxygenase-2 and inducible nitric oxide synthase were localized in the nucleus, and LPA did not modify their cellular distribution. Our results show that LPA-triggered regulatory pathways promote trophoblast endovascular response in vitro, suggesting a new role for LPA during spiral artery remodeling at the maternal-fetal interface.

Proinflammatory response of canine trophoblasts to Brucella canis infection.

Brucella canis infection is an important cause of late-term abortion in pregnant bitches. The pathophysiological mechanisms leading to B. canis-induced abortion are unknown, but heavily infected trophoblasts are consistently observed. As trophoblasts responses to other pathogens contribute to placental inflammation leading to abortion, the aim of the present study was to characterize the cytokine response of canine trophoblasts to B. canis infection. To achieve this, trophoblasts isolated from term placenta of healthy female dogs were infected with B. canis, culture supernatants were harvested for cytokine determinations, and the load of intracellular viable B. canis was determined at different times post-infection. Additionally, cytokine responses were assessed in non-infected trophoblasts stimulated with conditioned media (CM) from B. canis-infected canine monocytes and neutrophils. Finally, cytokine response and bacteria replication were assessed in canine placental explants infected ex vivo. B. canis successfully infected and replicated in primary canine trophoblasts, eliciting an increase in IL-8 and RANTES (CCL5) secretion. Moreover, the stimulation of trophoblasts with CM from B. canis-infected monocytes and neutrophils induced a significant increase in IL-8, IL-6 and RANTES secretion. B. canis replication was confirmed in infected placental explants and the infection elicited an increased secretion of TNF-α, IL-8, IL-6 and RANTES. This study shows that canine trophoblasts produce proinflammatory cytokines in response to B. canis infection and/or to stimulation with factors produced by infected monocytes and neutrophils. These cytokines may contribute to placental inflammation leading to abortion in B. canis-infected pregnant bitches.

Impact of chronic and acute inflammation on extra- and intracellular iron homeostasis.

Inflammation has a major impact on iron homeostasis. This review focuses on acute and chronic inflammation as it affects iron trafficking and, as a result, the availability of this essential micronutrient to the host. In situations of microbial infection, not only the host is affected but also the offending microorganisms, which, in general, not only require iron for their own growth but have evolved mechanisms to obtain it from the infected host. Key players in mammalian iron trafficking include several types of cells important to iron acquisition, homeostasis, and hematopoiesis (enterocytes, hepatocytes, macrophages, hematopoietic cells, and in the case of pregnancy, placental syncytiotrophoblast cells) and several forms of chaperone proteins, including, for nonheme iron, the transport protein transferrin and the intracellular iron-storage protein ferritin, and for heme iron, the chaperone proteins haptoglobin and hemopexin. Additional key players are the cell membrane-associated iron transporters, particularly ferroportin (FPN), the only protein known to modulate iron export from cells, and finally, the iron-regulatory hormone hepcidin, which, in addition to having antibacterial activity, regulates the functions of FPN. Interestingly, the impact of infection on iron homeostasis differs among pathogens whose mode of infection is mainly intracellular or extracellular. Understanding how inflammation affects each of these processes may be crucial for understanding how inflammation affects iron status, indicators of iron sufficiency, and iron supplementation during inflammation and how it may potentially result in a beneficial or detrimental impact on the host.

Progesterone and VIP cross-talk enhances phagocytosis and anti-inflammatory profile in trophoblast-derived cells.

Trophoblast cells produce several inmmuneregulators like the Vasoactive Intestinal Peptide (VIP) and P4 targeting multiple circuits, and also display an intese phagocytic ability allowing embryo implantation in a tolerogenic context. Here, we explored whether P4 and VIP- crosstalk modulates trophoblast cell function, focus on the phagocytic ability and the immune homeostasis maintenance. P4 enhanced the phagocytosis in trophoblast-derived cells quantified by the engulfment of latex-beads or eryptotic erythrocytes. P4 and VIP modulated the balance of anti/pro-inflammatory mediators, increasing TGF-ß expression, with no changes in IL-1, IL-6, or nitrites production. This modulation was accompained by transcription factor expression changes that could turn on tolerogenic programs represented by increased PPAR-γ and decreased IRF-5 expression. Finally, P4 stimulated VPAC2 expression in trophoblast cells and VPAC2 over-expression enhanced phagocytosis mimicking P4-effect. Therefore, P4 and VIP network enhances the phagocytic ability of trophoblast-derived cells, through a mechanism involving VPAC2 accompained with an anti-inflammatory context.

Trypanosoma cruzi induces cellular proliferation in the trophoblastic cell line BeWo.

Congenital transmission of Trypanosoma cruzi (T. cruzi) is partially responsible for the progressive globalization of Chagas disease. During congenital transmission the parasite must cross the placental barrier where the trophoblast, a continuous renewing epithelium, is the first tissue in contact with the parasite. The trophoblast turnover implies cellular proliferation, differentiation and apoptotic cell death. The epithelial turnover is considered part of innate immunity. We previously demonstrated that T. cruzi induces cellular differentiation and apoptosis in this tissue. Here we demonstrate that T. cruzi induces cellular proliferation in a trophoblastic cell line. We analyzed the cellular proliferation in BeWo cells by determining DNA synthesis by BrdU incorporation assays, mitotic index, cell cycle analysis by flow cytometry, as well as quantification of nucleolus organizer regions by histochemistry and expression of the proliferation markers PCNA and Ki67 by Western blotting and/or immunofluorescence. Additionally, we determined the ERK1/2 MAPK pathway activation by the parasite by Western blotting.

Spatiotemporal expression profile of proteases and immunological, angiogenic, hormonal and apoptotic mediators in rat placenta before and during intrauterine trophoblast migration.

The gene and/or protein expression of proteases and immunological, angiogenic, hormonal and apoptotic mediators was evaluated in rat placenta before and during intrauterine trophoblast migration. The depth of interstitial and endovascular intrauterine trophoblast invasion and the immunohistochemical expression of vascular endothelial growth factor (VEGF), fetal liver kinase 1 (Flk1), interferon (IFN)-γ, migration inhibitory factor (MIF), and inducible nitric oxide synthase (iNOS; also known as nitric oxide synthase (NOS) 2) were evaluated. In addition, the expression of the Vegf, Flk1, placental growth factor (Pigf), soluble fms-like tyrosine kinase 1 (sFlt1), placental lactogen 1 (Pl1), proliferin-related protein (rPlf), placental leptin (Lep), Toll-like receptor 2 (Tlr2), Toll-like receptor 4 (Tlr4), Infg, Mif, tumour necrosis factor-α (Tnf), interleukin-10 (Il10), Nos2, caspase 3 (Casp3), Bax, Bcl2, matrix metalloproteinase 2 (Mmp2) and matrix metalloproteinase 9 (Mmp9) genes was determined by real-time reverse transcription-polymerase chain reaction. At 10 days gestation, gene expression of Tlr2, Tlr4, Tnf, Infg, Il10, Casp3, Pigf, sFlt1 and Lep (P<0.05) were higher than at 14 and/or 19 days of gestation. The beginning of intrauterine trophoblast invasion, i.e., at 14 days of gestation, coincided with higher gene and/or protein expression of MMP9, VEGF, Flk1, NOS2, MIF, BAX and rPlf compared to days 10 and 19 (P<0.05). In contrast, gene expression of Mmp2 and Pl1 was higher at the end of trophoblast invasion compared to 10 and 14 days of gestation (P<0.05). In conclusion, before intrauterine trophoblast migration, expression of TLRs and immunological and pro-apoptotic mediators is higher, whereas the beginning of trophoblast migration is characterised by higher expression of the pro-angiogenic factors NOS2 and MMP9. In contrast, MMP2 and PL1 expression is higher at the end of intrauterine trophoblast migration.

Natural Killer Cell Reduction and Uteroplacental Vasculopathy.

Uterine natural killer cells are important for uteroplacental development and pregnancy maintenance. Their role in pregnancy disorders, such as preeclampsia, is unknown. We reduced the number of natural killer cells by administering rabbit anti-asialo GM1 antiserum in an established rat preeclamptic model (female human angiotensinogen×male human renin) and evaluated the effects at the end of pregnancy (day 21), compared with preeclamptic control rats receiving normal rabbit serum. In 100% of the antiserum-treated, preeclamptic rats (7/7), we observed highly degenerated vessel cross sections in the mesometrial triangle at the end of pregnancy. This maternal uterine vasculopathy was characterized by a total absence of nucleated/living cells in the vessel wall and perivascularly and prominent presence of fibrosis. Furthermore, there were no endovascular trophoblast cells within the vessel lumen. In the control, normal rabbit serum-treated, preeclamptic rats, only 20% (1/5) of the animals displayed such vasculopathy. We confirmed the results in healthy pregnant wild-type rats: after anti-asialo GM1 treatment, 67% of maternal rats displayed vasculopathy at the end of pregnancy compared with 0% in rabbit serum-treated control rats. This vasculopathy was associated with a significantly lower fetal weight in wild-type rats and deterioration of fetal brain/liver weight ratio in preeclamptic rats. Anti-asialo GM1 application had no influence on maternal hypertension and albuminuria during pregnancy. Our results show a new role of natural killer cells during hypertensive pregnancy in maintaining vascular integrity. In normotensive pregnancy, this integrity seems important for fetal growth.

Vasoactive Intestinal Peptide modulates trophoblast-derived cell line function and interaction with phagocytic cells through autocrine pathways.

Trophoblast cells migrate and invade the decidual stroma in a tightly regulated process to maintain immune homeostasis at the maternal-placental interface during the first weeks of pregnancy. Locally synthesized factors modulate trophoblast cell function and their interaction with maternal leukocytes to promote the silent clearance of apoptotic cells. The vasoactive intestinal peptide (VIP) is a pleiotropic polypeptide with trophic and anti-inflammatory effects in murine pregnancy models. We explored the effect of VIP on two human first trimester trophoblast cell lines, particularly on their migration, invasiveness and interaction with phagocytic cells, and the signalling and regulatory pathways involved. We found that VIP enhanced trophoblast cell migration and invasion through the activation of high affinity VPAC receptors and PKA-CRE signalling pathways. VIP knocked-down trophoblast cells showed reduced migration in basal and leukemic inhibitor factor (LIF)-elicited conditions. In parallel, VIP-silenced trophoblast cells failed to induce the phagocytosis of apoptotic bodies and the expression of immunosuppressant markers by human monocytes. Our results suggest that VIP-mediated autocrine pathways regulate trophoblast cell function and contribute to immune homeostasis maintenance at placentation and may provide new clues for therapeutic intervention in pregnancies complicated by defective deep placentation.

Proteomic Profile of Brucella abortus-Infected Bovine Chorioallantoic Membrane Explants.

Brucella abortus is the etiological agent of bovine brucellosis, a zoonotic disease that causes significant economic losses worldwide. The differential proteomic profile of bovine chorioallantoic membrane (CAM) explants at early stages of infection with B. abortus (0.5, 2, 4, and 8 h) was determined. Analysis of CAM explants at 0.5 and 4 h showed the highest differences between uninfected and infected CAM explants, and therefore were used for the Differential Gel Electrophoresis (DIGE). A total of 103 spots were present in only one experimental group and were selected for identification by mass spectrometry (MALDI/ToF-ToF). Proteins only identified in extracts of CAM explants infected with B. abortus were related to recognition of PAMPs by TLR, production of reactive oxygen species, intracellular trafficking, and inflammation.

Effects of Sildenafil Citrate and Heparin Treatments on Placental Cell Morphology in a Murine Model of Pregnancy Loss.

Lipopolysaccharide (LPS) injections during pregnancy are well established as models for pregnancy complications, including fetal growth restriction (FGR), thrombophilia, preterm labor and abortion. Indeed, inflammation, as induced by LPS injection has been described as a pivotal factor in cases of miscarriage related to placental tissue damage. The phosphodiesterase-5 inhibitor sildenafil (Viagra®) is currently used to treat FGR cases in women, while low-molecular weight heparin (Fragmin®) is a standard treatment for recurrent miscarriage (RM). However, the pathways and cellular dynamics involved in RM are not completely understood. The aim of this study was to evaluate the protective effect of sildenafil and dalteparin in a mouse model of LPS-induced abortion. Histopathology, ultrastructural analysis and immunofluorescence for P-selectin were studied in two different placental cell types: trophoblast cells and labyrinth endothelial cells. Treatment with sildenafil either alone or in combination with heparin showed the best response against LPS-induced injury during pregnancy. In conclusion, our results support the use of these drugs as future therapeutic agents that may protect the placenta against inflammatory injury in RM events. Analyses of the ultrastructure and placental immunophysiology are important to understand the mechanism underlying RM. These findings may spark future studies and aid in the development of new therapies in cases of RM.

Decoding the chemokine network that links leukocytes with decidual cells and the trophoblast during early implantation.

Chemokine network is central to the innate and adaptive immunity and entails a variety of proteins and membrane receptors that control physiological processes such as wound healing, angiogenesis, embryo growth and development. During early pregnancy, the chemokine network coordinates not only the recruitment of different leukocyte populations to generate the maternal-placental interface, but also constitutes an additional checkpoint for tissue homeostasis maintenance. The normal switch from a pro-inflammatory to an anti-inflammatory predominant microenvironment characteristic of the post-implantation stage requires redundant immune tolerance circuits triggered by key master regulators. In this review we will focus on the recruitment and conditioning of maternal immune cells to the uterus at the early implantation period with special interest on high plasticity macrophages and dendritic cells and their ability to induce regulatory T cells. We will also point to putative immunomodulatory polypeptides involved in immune homeostasis maintenance at the maternal-placental interface.