Altered decidual and placental catabolism of vitamin D may contribute to the aetiology of spontaneous miscarriage.

INTRODUCTION: Vitamin D catabolizing enzymes, along with vitamin D receptor (VDR) and vitamin D binding protein (DBP) are expressed in the decidua and placenta during pregnancy and capable of synthesizing active vitamin D. Vitamin D plays roles in immunoregulation and trophoblast invasion, key features of a successful pregnancy. Epidemiological data suggests that vitamin D deficiency is associated with both spontaneous and recurrent miscarriage but few studies have investigated the expression of the key vitamin D catabolizing enzymes in miscarriage. METHODS: Placenta and decidua were collected after termination of apparently normal pregnancies (controls, n = 22) or spontaneous miscarriage (n = 20). Immunohistochemical staining, Western Blot and qRT-PCR were performed for CYP27B1, CYP24A1, CYP2R1, VDR and DBP (not qRT-PCR). HTR-8/SVneo cells were cultured in CoCL2 (hypoxic mimetic) or LPS (bacterial infection mimetic) for 24 h, RNA extracted and qRT-PCR performed for CYP27B1, CYP24A1, CYP2R1 and VDR. RESULTS: In spontaneous miscarriage, placental and decidual expression of CYP27B1 was reduced, while expression of CYP24A1, VDR and DBP was increased. When a trophoblast cell line was treated with CoCL2 expression of CYP27B1 was increased and CYP24A1 was reduced, while LPS induced expression of VDR. DISCUSSION: This is the first report of altered utero-placental vitamin D catabolism in spontaneous miscarriage. It is becoming accepted that women who are undergoing assisted reproductive technologies should ensure they have sufficient vitamin D levels prior to pregnancy, these data support that all women should ensure they are vitamin D replete before planning to get pregnant.

Quantification of spiral artery remodelling using an Adobe Photoshop-based technique.

Uterine spiral arteries undergo remodelling in normal pregnancy, with replacement of the musculoelastic arterial media by fibrinoid containing extravillous trophoblast cells. Deficient spiral artery remodelling is associated with several adverse pregnancy outcomes. Although there are distinct components of spiral artery remodelling, assessment is subjective and often based on an overall impression of morphology. We aimed to develop a quantitative approach for assessment of uterine spiral artery remodelling. Placental bed biopsies were immunostained using smooth muscle markers, digital images of spiral arteries were captured and Adobe Photoshop was used to analyse positive immunostaining. The method was then used to investigate variation in the same vessel at different levels within a paraffin block, and the effect of parity, pre-eclampsia or miscarriage on vascular smooth muscle cell content. Results were also compared with a more subjective morphology-based assessment system. There was good intra- and interobserver agreement and the method correlated well with the more subjective assessment system. There was an overall reduction in vascular smooth muscle, as detected by caldesmon 1 (h-caldesmon) immunopositivity, with increasing gestational age from 8 weeks to term. A previous pregnancy did not affect the amount of spiral artery smooth muscle. Comparison of pre-eclampsia and late miscarriage samples with controls of the appropriate gestational age demonstrated increased medial smooth muscle in pathological samples. This technique provides a simple, rapid, reproducible and inexpensive approach to quantitative assessment of spiral artery remodelling in normal and pathological human pregnancy, a process which although fundamental for successful pregnancy, is still incompletely understood.

Uterine spiral artery muscle dedifferentiation.

STUDY QUESTION: Is vascular smooth muscle cell (VSMC) dedifferentiation a feature of uterine spiral artery (SpA) remodelling in early human pregnancy? SUMMARY ANSWER: Remodelling of human uterine SpAs is associated with dedifferentiation of VSMCs and can be induced in vitro by uterine natural killer (uNK) cells and extravillous trophoblast cells (EVTs). WHAT IS KNOWN ALREADY: Uterine SpAs undergo profound morphological changes in normal pregnancy with replacement of the musculoelastic arterial wall structure by fibrinoid containing EVTs. The fate of VSMCs in SpA remodelling is unknown; in guinea pig uterine artery VSMCs dedifferentiate, remain in the vessel wall and differentiate after parturition to restore the arterial wall. There is increasing evidence that uNK cells play a role in SpA remodelling. We hypothesized that SpA remodelling in human pregnancy is associated with VSMC dedifferentiation, initiated by uNK cell-derived growth factors. STUDY DESIGN, SIZE, DURATION: Formalin fixed, paraffin embedded placental bed biopsies were immunostained for angiogenic growth factor (AGF) receptors and markers of VSMC differentiation. An in vitro model of SpA remodelling using chorionic plate arteries (CPAs) was used to test the effect of different cell types and AGFs on VSMC differentiation. PARTICIPANTS/MATERIALS, SETTING, METHODS: Placental bed biopsies were immunostained for vascular endothelial growth factor receptors 1-3 (VEGF-R1, VEGF-R2, VEGF-R3), transforming growth factor beta 1 receptors I and II (TGF-ßRI, TGF-ßRII), interferon gamma receptors 1 and 2 (IFN-γR1, IFN-γR2), Tie2, α-smooth muscle actin (α-SMA), H-caldesmon (H-Cal), myosin heavy chain (MyHC), osteopontin and smoothelin. Staining intensity was assessed using a modified quickscore. Expression by VSMCs of the AGF receptors was confirmed by laser capture microdissection and real-time RT-PCR of non-remodelled SpAs, after laser removal of the endothelium. As an in vitro model, VSMC differentiation was assessed in CPAs by immunohistochemistry after culture in uNK cell-conditioned medium (CM), EVT-CM, uNK cell/EVT co-culture CM, Ang-1, Ang-2, IFN-γ, VEGF-A and VEGF-C, and after blocking of both Ang-1 and Ang-2 in uNK-CM. MAIN RESULTS AND THE ROLE OF CHANCE: SpA VSMC expression of Tie-2 (P = 0.0007), VEGF-R2 (P = 0.005) and osteopontin (P = 0.0001) increased in partially remodelled SpAs compared with non-remodelled SpAs, while expression of contractile VSMC markers was reduced (α-SMA P < 0.0001, H-Cal P = 0.03, MyHC P = 0.03, smoothelin P = 0.0001). In the in vitro CPA model, supernatants from purified uNK cell (H-Cal P < 0.0001, MyHC P = 0.03, α-SMA P = 0.02, osteopontin P = 0.03), EVT (H-Cal P = 0.0006, MyHC P = 0.02, osteopontin P = 0.01) and uNK cell/EVT co-cultures (H-Cal P = 0.001, MyHC P = 0.05, osteopontin P = 0.02) at 12-14 weeks, but not 8-10 weeks, gestational age induced reduced expression of contractile VSMC markers and increased osteopontin expression. Addition of exogenous (10 ng/ml) Ang-1 (P = 0.006) or Ang-2 (P = 0.009) also reduced H-Cal expression in the CPA model. Inhibition of Ang-1 (P = 0.0004) or Ang-2 (P = 0.004) in uNK cell supernatants blocked the ability of uNK cell supernatants to reduce H-Cal expression. LIMITATIONS, REASONS FOR CAUTION: This is an in vitro study and the role of uNK cells, Ang-1 and Ang-2 in SpA remodelling in vivo has not yet been shown. WIDER IMPLICATIONS OF THE FINDINGS: VSMC dedifferentiation is a feature of early SpA remodelling and uNK cells and EVT play key roles in this process by secretion of Ang-1 and Ang-2. This is one of the first studies to suggest a direct role for Ang-1 and Ang-2 in VSMC biology. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by a grant from British Biotechnology and Biosciences Research Council (BB/E016790/1). The authors have no competing interests to declare.

Interleukin-34 is present at the fetal-maternal interface and induces immunoregulatory macrophages of a decidual phenotype in vitro.

STUDY QUESTION: Is the newly discovered cytokine interleukin (IL)-34 expressed at the human fetal-maternal interface in order to influence polarization of monocytes into macrophages of a decidual immunoregulatory phenotype? SUMMARY ANSWER: IL-34 was found to be present at the fetal-maternal interface, in both fetal placenta and maternal decidua, and it was able to polarize monocytes into macrophages of a decidual phenotype. WHAT IS KNOWN ALREADY: IL-34 was shown to bind to the same receptor as macrophage-colony stimulating factor (M-CSF), which has an important immunomodulatory role at the fetal-maternal interface, for example by polarizing decidual macrophages to an M2-like regulatory phenotype. IL-34 is known to regulate macrophage subsets, such as microglia and Langerhans cells, but its presence at the fetal-maternal interface is unknown. STUDY DESIGN, SIZE, DURATION: The presence of IL-34 at the fetal-maternal interface was evaluated by immunohistochemistry (IHC) and ELISA in placental and decidual tissues as well as in isolated trophoblast cells and decidual stromal cells obtained from first trimester elective surgical terminations of pregnancy (n = 49). IL-34 expression was also assessed in third trimester placental biopsies from women with (n = 21) or without (n = 15) pre-eclampsia. The effect of IL-34 on macrophage polarization was evaluated in an in vitro model of blood monocytes obtained from healthy volunteers (n = 14). In this model, granulocyte macrophage-colony stimulating factor (GM-CSF) serves as a growth factor for M1-like polarization, and M-CSF as a growth factor for M2-like polarization. PARTICIPANTS/MATERIALS, SETTING, METHODS: First trimester placental and decidual tissues were obtained from elective pregnancy terminations. Placental biopsies were obtained from women with pre-eclampsia and matched controls in the delivery ward. Polarization of macrophages in vitro was determined by flow-cytometric phenotyping and secretion of cytokines and chemokines in cell-free supernatants by multiplex bead assay. MAIN RESULTS AND THE ROLE OF CHANCE: Our study shows that IL-34 is produced at the fetal-maternal interface by both placental cyto- and syncytiotrophoblasts and decidual stromal cells. We also show that IL-34, in vitro, is able to polarize blood monocytes into macrophages with a phenotype (CD14highCD163+CD209+) and cytokine secretion pattern similar to that of decidual macrophages. The IL-34-induced phenotype was similar, but not identical to the phenotype induced by M-CSF, and both IL-34- and M-CSF-induced macrophages were significantly different (P < 0.05-0.0001 depending on marker) from GM-CSF-polarized M1-like macrophages. Our findings suggest that IL-34 is involved in the establishment of the tolerant milieu found at the fetal-maternal interface by skewing polarization of macrophages into a regulatory phenotype. LIMITATIONS, REASONS FOR CAUTION: Although it is clear that IL-34 is present at the fetal-maternal interface and polarizes macrophages in vitro, its precise role in vivo remains to be established. WIDER IMPLICATIONS OF THE FINDINGS: The recently discovered cytokine IL-34 is present at the fetal-maternal interface and has immunomodulatory properties with regard to induction of decidual macrophages, which are important for a healthy pregnancy. Knowledge of growth factors related to macrophage polarization can potentially be translated to treatment of pregnancy complications involving dysregulation of this process. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by grants from the Medical Research Council (Grant K2013-61X-22310-01-04), the Research Council of South-East Sweden (FORSS), and the County Council of Östergötland, Sweden. No author has any conflicts of interest to declare.

IFPA meeting 2015 workshop report IV: placenta and obesity; stem cells of the feto-maternal interface; placental immunobiology and infection.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At the 2015 IFPA annual meeting there were 12 themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology and collectively covered areas of obesity and the placenta, stem cells of the feto-maternal interface, and placental immunobiology and infection.

IFPA meeting 2014 workshop report: Animal models to study pregnancy pathologies; new approaches to study human placental exposure to xenobiotics; biomarkers of pregnancy pathologies; placental genetics and epigenetics; the placenta and stillbirth and fetal growth restriction.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2014 there were six themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of animal models, xenobiotics, pathological biomarkers, genetics and epigenetics, and stillbirth and fetal growth restriction.

Triiodothyronine regulates angiogenic growth factor and cytokine secretion by isolated human decidual cells in a cell-type specific and gestational age-dependent manner.

STUDY QUESTION: Does triiodothyronine (T3) regulate the secretion of angiogenic growth factors and cytokines by human decidual cells isolated from early pregnancy? SUMMARY ANSWER: T3 modulates the secretion of specific angiogenic growth factors and cytokines, with different regulatory patterns observed amongst various isolated subpopulations of human decidual cells and with a distinct change between the first and second trimesters of pregnancy. WHAT IS KNOWN ALREADY: Maternal thyroid dysfunction during early pregnancy is associated with complications of malplacentation including miscarriage and pre-eclampsia. T3 regulates the proliferation and apoptosis of fetal-derived trophoblasts, as well as promotes the invasive capability of extravillous trophoblasts (EVT). We hypothesize that T3 may also have a direct impact on human maternal-derived decidual cells, which are known to exert paracrine regulation upon trophoblast behaviour and vascular development at the uteroplacental interface. STUDY DESIGN, SIZE, DURATION: This laboratory-based study used human decidua from first (8-11 weeks; n = 18) and second (12-16 weeks; n = 12) trimester surgical terminations of apparently uncomplicated pregnancies. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primary cultures of total decidual cells, and immunomagnetic bead-isolated populations of stromal-enriched (CD10+) and stromal-depleted (CD10-) cells, uterine natural killer cells (uNK cells; CD56+) and macrophages (CD14+) were assessed for thyroid hormone receptors and transporters by immunocytochemistry. Each cell population was treated with T3 (0, 1, 10, 100 nM) and assessments were made of cell viability (MTT assay) and angiogenic growth factor and cytokine secretion (immunomediated assay). The effect of decidual cell-conditioned media on EVT invasion through Matrigel(®) was evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: Immunocytochemistry showed the expression of thyroid hormone transporters (MCT8, MCT10) and receptors (TRα1, TRß1) required for thyroid hormone-responsiveness in uNK cells and macrophages from the first trimester. The viability of total decidual cells and the different cell isolates were unaffected by T3 so changes in cell numbers could not account for any observed effects. In the first trimester, T3 decreased VEGF-A secretion by total decidual cells (P < 0.05) and increased angiopoietin-2 secretion by stromal-depleted cells (P < 0.05) but in the second trimester total decidual cells showed only increased angiogenin secretion (P < 0.05). In the first trimester, T3 reduced IL-10 secretion by total decidual cells (P < 0.05), and reduced granulocyte macrophage colony stimulating factor (P < 0.01), IL-8 (P < 0.05), IL-10 (P < 0.01), IL-1ß (P < 0.05) and monocyte chemotactic protein -1 (P < 0.001) secretion by macrophages, but increased tumour necrosis factor-α secretion by stromal-depleted cells (P < 0.05) and increased IL-6 by uNK cells (P < 0.05). In contrast, in the second trimester T3 increased IL-10 secretion by total decidual cells (P < 0.01) but did not affect cytokine secretion by uNK cells and macrophages. Conditioned media from first trimester T3-treated total decidual cells and macrophages did not alter EVT invasion compared with untreated controls. Thus, treatment of decidual cells with T3 resulted in changes in both angiogenic growth factor and cytokine secretion in a cell type-specific and gestational age-dependent manner, with first trimester decidual macrophages being the most responsive to T3 treatment, but these changes in decidual cell secretome did not affect EVT invasion in vitro. LIMITATIONS, REASONS FOR CAUTION: Our results are based on in vitro findings and we cannot be certain if a similar response occurs in human pregnancy in vivo. WIDER IMPLICATIONS OF THE FINDINGS: Optimal maternal thyroid hormone concentrations could play a critical role in maintaining a balanced inflammatory response in early pregnancy to prevent fetal immune rejection and promote normal placental development through the regulation of the secretion of critical cytokines and angiogenic growth factors by human decidual cells. Our data suggest that there is an ontogenically determined regulatory 'switch' in T3 responsiveness between the first and second trimesters, and support the notion that the timely and early correction of maternal thyroid dysfunction is critical in influencing pregnancy outcomes. STUDY FUNDING/COMPETING INTEREST(S): This study is funded by Wellbeing of Women (RG/1082/09 to S.Y.C., M.D.K., J.A.F., L.S.L., G.E.L.) and Action Medical Research - Henry Smith Charity (SP4335 to M.D.K., S.Y.C., L.S.L., J.A.F.). The authors have no conflicts of interest to disclose.

IFPA Meeting 2013 Workshop Report II: use of 'omics' in understanding placental development, bioinformatics tools for gene expression analysis, planning and coordination of a placenta research network, placental imaging, evolutionary approaches to understanding pre-eclampsia.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At the IFPA meeting 2013 twelve themed workshops were presented, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of new technologies for placenta research: 1) use of 'omics' in understanding placental development and pathologies; 2) bioinformatics and use of omics technologies; 3) planning and coordination of a placenta research network; 4) clinical imaging and pathological outcomes; 5) placental evolution.

IFPA Meeting 2013 Workshop Report III: maternal placental immunological interactions, novel determinants of trophoblast cell fate, dual ex vivo perfusion of the human placenta.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2013 there were twelve themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of placental function, cell turnover and immunology: 1) immunology; 2) novel determinants of placental cell fate; 3) dual perfusion of human placental tissue.

IFPA Meeting 2013 Workshop Report I: diabetes in pregnancy, maternal dyslipidemia in pregnancy, oxygen in placental development, stem cells and pregnancy pathology.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2013 there were twelve themed workshops, four of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of pregnancy pathologies and placental metabolism: 1) diabetes in pregnancy; 2) lipids, fatty acids and the placenta; 3) oxygen in placental development and pathologies; 4) stem cells and pathologies.

IFPA Meeting 2012 Workshop Report I: comparative placentation and animal models, advanced techniques in placental histopathology, human pluripotent stem cells as a model for trophoblast differentiation.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of models and technical issues involved in placenta research: 1) comparative placentation and animal models; 2) advanced techniques in placental histopathology; 3) human pluripotent stem cells as a model for trophoblast differentiation.

IFPA Meeting 2012 Workshop Report III: trophoblast deportation, gestational trophoblastic disease, placental insufficiency and fetal growth restriction, trophoblast over-invasion and accreta-related pathologies, placental thrombosis and fibrinolysis.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of clinical research and pregnancy disorders: 1) trophoblast deportation; 2) gestational trophoblastic disease; 3) placental insufficiency and fetal growth restriction; 4) trophoblast overinvasion and accreta-related pathologies; 5) placental thrombosis and fibrinolysis.

IFPA Meeting 2012 Workshop Report II: epigenetics and imprinting in the placenta, growth factors and villous trophoblast differentiation, role of the placenta in regulating fetal exposure to xenobiotics during pregnancy, infection and the placenta.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, four of which are summarized in this report. These workshops related to various aspects of placental biology: 1) epigenetics and imprinting in the placenta; 2) growth factors and villous trophoblast differentiation; 3) role of the placenta in regulating fetal exposure to xenobiotics during pregnancy; 4) infection and the placenta.

Effects of local decidua on trophoblast invasion and spiral artery remodeling in focal placenta creta - an immunohistochemical study.

OBJECTIVES: Placenta creta is an increasingly prevalent cause of maternal morbidity/mortality. Decidua is at least focally defective and extravillous trophoblast (EVT) may be abnormal. The study aims to compare differences in migratory trophoblast and spiral artery remodeling between areas with and without decidua at the placental implantation site. STUDY DESIGN: Sixteen (12 creta, 4 non-creta) caesarean hysterectomy specimens were studied immunohistochemically. Invasive EVT and multinucleate trophoblast giant cells (MTGC) were quantified; confluent EVT (>5 opposed EVTs) and spiral artery remodeling were assessed semi-quantitatively. RESULTS: In 6 cases, placenta creta was focal. Compared to placenta creta with local decidua, cases without local decidua had increased interstitial EVT cells (×200 field) (SEM 45.6 [4.9] vs. 80.5 [3.9], p < 0.0001), fewer multinucleate trophoblast giant cells (expressed as a percentage of total EVT) (0.8 [0.3] vs. 31.5 [2.2]% p < 0.0001) and EVT was more confluent (p < 0.0001). In contrast, placenta creta cases with local decidua had a greater degree of spiral artery remodeling (mean remodeling score 1.65 [0.07] vs. 1.13 [0.05], p < 0.0001) associated with increased intramural trophoblast (p = 0.0008). The only difference between placenta creta with local decidua and normal placentation cases was an increased number of interstitial EVT cells in creta cases (45.6 [4.9] vs. 24.8 [3.2], p = 0.04). CONCLUSIONS: Numbers of interstitial EVT are increased in placenta creta, more so in cases without local decidua. Despite this spiral artery modeling is reduced in placenta creta cases with no decidua. The results emphasize the crucial role of decidua in control of trophoblast invasion and spiral artery remodeling.

IFPA Meeting 2011 workshop report II: Angiogenic signaling and regulation of fetal endothelial function; placental and fetal circulation and growth; spiral artery remodeling.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2011 there were twelve themed workshops, three of which are summarized in this report. These workshops related to vascular systems and circulation in the mother, placenta and fetus, and were divided in to 1) angiogenic signaling and regulation of fetal endothelial function; 2) placental and fetal circulation and growth; 3) spiral artery remodeling.

IFPA Meeting 2011 workshop report I: Placenta: Predicting future health; roles of lipids in the growth and development of feto-placental unit; placental nutrient sensing; placental research to solve clinical problems--a translational approach.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2011 there were twelve themed workshops, four of which are summarized in this report. These workshops related to both basic science and clinical research into placental growth and nutrient sensing and were divided into 1) placenta: predicting future health; 2) roles of lipids in the growth and development of feto-placental unit; 3) placental nutrient sensing; 4) placental research to solve clinical problems: a translational approach.

IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells.

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.

IFPA Meeting 2010 Workshop Report I: Immunology; ion transport; epigenetics; vascular reactivity; epitheliochorial placentation; proteomics.

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 there were twelve themed workshops, six of which are summarized in this report. 1. The immunology workshop focused on normal and pathological functions of the maternal immune system in pregnancy. 2. The transport workshop dealt with regulation of ion and water transport across the syncytiotrophoblast of human placenta. 3. The epigenetics workshop covered DNA methylation and its potential role in regulating gene expression in placental development and disease. 4. The vascular reactivity workshop concentrated on methodological approaches used to study placental vascular function. 5. The workshop on epitheliochorial placentation covered current advances from in vivo and in vitro studies of different domestic species. 6. The proteomics workshop focused on a variety of techniques and procedures necessary for proteomic analysis and how they may be implemented for placental research.

IFPA Meeting 2010 Workshops Report II: Placental pathology; trophoblast invasion; fetal sex; parasites and the placenta; decidua and embryonic or fetal loss; trophoblast differentiation and syncytialisation.

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications.

Role of interleukin 8 in uterine natural killer cell regulation of extravillous trophoblast cell invasion.

BACKGROUND: Extravillous trophoblast cell (EVT) invasion of maternal tissues is critical for successful pregnancy. Decidual factors, including uterine natural killer (uNK) and T cell derived cytokines play a role in regulating this process. Interleukin (IL) 8 has been implicated as a regulator of EVT invasion. HYPOTHESIS: uNK cell stimulation of EVT invasion is associated with IL-8 levels. METHODS: CD8+, total decidual and CD56(+) uNK cells (8-10 and 12-14 weeks gestational age) were cultured. IL-8 mRNA and protein levels were determined. IL-8 receptors (IL-8RA and IL-8RB) were localised in first trimester placental bed biopsies. The effect of IL-8 +/- IL-8 neutralising antibodies and CD8+ T cell or uNK cell supernatants +/- IL-8 neutralising antibodies on EVT invasion was assessed. EVT secreted levels of MMP-2, MMP-9, uPA, PAI-1 and PAI-2 were assessed by substrate zymography or Western Blot. RESULTS: High levels of IL-8 protein and mRNA were detected in all samples. IL-8RA and IL-8RB were expressed by EVT. Exogenous IL-8 stimulated EVT invasion in a paracrine manner. uNK cell supernatants, but not CD8+ cell supernatants, stimulated EVT invasion. IL-8 neutralising antibody partially abrogated this uNK cell stimulated invasion. IL-8 increased levels of secreted MMP-2, but did not alter any of the other proteases or protease inhibitors tested. CONCLUSION: uNK cell stimulation of EVT invasion is partially mediated by IL-8. Unstimulated CD8+ T cells do not alter EVT invasion despite secreting similar levels of IL-8 as uNK cells.