Tim-3 Coordinates Macrophage-Trophoblast Crosstalk via Angiogenic Growth Factors to Promote Pregnancy Maintenance.

T-cell immunoglobulin mucin-3 (Tim-3) is an important checkpoint that induces maternal-fetal tolerance in pregnancy. Macrophages (Mφs) play essential roles in maintaining maternal-fetal tolerance, remodeling spiral arteries, and regulating trophoblast biological behaviors. In the present study, the formation of the labyrinth zone showed striking defects in pregnant mice treated with Tim-3 neutralizing antibodies. The adoptive transfer of Tim-3+Mφs, rather than Tim-3-Mφs, reversed the murine placental dysplasia resulting from Mφ depletion. With the higher production of angiogenic growth factors (AGFs, including PDGF-AA, TGF-α, and VEGF), Tim-3+dMφs were more beneficial in promoting the invasion and tube formation ability of trophoblasts. The blockade of AGFs in Tim-3+Mφs led to the narrowing of the labyrinthine layer of the placenta, compromising maternal-fetal tolerance, and increasing the risk of fetal loss. Meanwhile, the AGFs-treated Tim-3-Mφs could resolve the placental dysplasia and fetal loss resulting from Mφ depletion. These findings emphasized the vital roles of Tim-3 in coordinating Mφs-extravillous trophoblasts interaction via AGFs to promote pregnancy maintenance and in extending the role of checkpoint signaling in placental development. The results obtained in our study also firmly demonstrated that careful consideration of reproductive safety should be taken when selecting immune checkpoint and AGF blockade therapies in real-world clinical care.

Non-invasive prenatal testing in the management of twin pregnancies.

Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta-analyses show that non-invasive prenatal testing (NIPT) through analysis of cell-free DNA (cf-DNA) is superior to serum and ultrasound-based tests. The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT. Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf-DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf-DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies.

Bone-marrow-derived endothelial progenitor cells contribute to vasculogenesis of pregnant mouse uterus†.

Angiogenesis is essential for cyclic endometrial growth, implantation, and pregnancy maintenance. Vasculogenesis, the formation of new blood vessels by bone marrow (BM)-derived endothelial progenitor cells (EPCs), has been shown to contribute to endometrial vasculature. However, it is unknown whether vasculogenesis occurs in neovascularization of the decidua during pregnancy. To investigate the contribution of BM-derived EPCs to vascularization of the pregnant uterus, we induced non-gonadotoxic submyeloablation by 5-fluorouracil administration to wild-type FVB/N female mice recipients followed by BM transplantation from transgenic mice expressing green fluorescent protein (GFP) under regulation of Tie2 endothelial-specific promoter. Following 1 month, Tie2-GFP BM-transplanted mice were bred and sacrificed at various gestational days (ED6.5, ED10.5, ED13.5, ED18.5, and postpartum). Bone-marrow-transplanted non-pregnant and saline-injected pregnant mice served as controls (n = 5-6/group). Implantation sites were analyzed by flow cytometry, immunohistochemistry, and immunofluorescence. While no GFP-positive EPCs were found in non-pregnant or early pregnant uteri of BM-transplanted mice, GFP-positive EPCs were first detected in pregnant uterus on ED10.5 (0.12%) and increased as the pregnancy progressed (1.14% on ED13.5), peaking on ED18.5 (1.42%) followed by decrease in the postpartum (0.9%). The percentage of endothelial cells that were BM-derived out of the total endothelial cell population in the implantation sites (GFP+CD31+/CD31+) were 9.3%, 15.8%, and 6.1% on ED13.5, ED18.5, and postpartum, respectively. Immunohistochemistry demonstrated that EPCs incorporated into decidual vasculature, and immunofluorescence showed that GFP-positive EPCs colocalized with CD31 in vascular endothelium of uterine implantation sites, confirming their endothelial lineage. Our findings indicate that BM-derived EPCs contribute to vasculogenesis of the pregnant mouse decidua.

New perspective on conceptus estrogens in maternal recognition and pregnancy establishment in the pig†.

The proposed signal for maternal recognition of pregnancy in pigs is estrogen (E2), produced by the elongating conceptuses between days 11 to 12 of pregnancy with a more sustained increase during conceptus attachment and placental development on days 15 to 30. To understand the role of E2 in porcine conceptus elongation and pregnancy establishment, a loss-of-function study was conducted by editing aromatase (CYP19A1) using CRISPR/Cas9 technology. Wild-type (CYP19A1+/+) and (CYP19A1-/-) fibroblast cells were used to create embryos through somatic cell nuclear transfer, which were transferred into recipient gilts. Elongated and attaching conceptuses were recovered from gilts containing CYP19A1+/+ or CYP19A1-/- embryos on day 14 and 17 of pregnancy. Total E2 in the uterine flushings of gilts with CYP19A1-/- embryos was lower than recipients containing CYP19A1+/+ embryos with no difference in testosterone, PGF2α, or PGE2 on either day 14 or 17. Despite the loss of conceptus E2 production, CYP19A1-/- conceptuses were capable of maintaining the corpora lutea. However, gilts gestating CYP19A1-/- embryos aborted between days 27 and 31 of gestation. Attempts to rescue the pregnancy of CYP19A1-/- gestating gilts with exogenous E2 failed to maintain pregnancy. However, CYP19A1-/- embryos could be rescued when co-transferred with embryos derived by in vitro fertilization. Endometrial transcriptome analysis revealed that ablation of conceptus E2 resulted in disruption of a number biological pathways. Results demonstrate that intrinsic E2 conceptus production is not essential for pre-implantation development, conceptus elongation, and early CL maintenance, but is essential for maintenance of pregnancy beyond 30 days .

Mechanisms for the establishment and maintenance of pregnancy: synergies from scientific collaborations.

Research on the functions of interferon tau (IFNT) led to the theory of pregnancy recognition signaling in ruminant species. But IFNT does much more as it induces expression of interferon regulatory factor 2 (IRF2) in uterine luminal (LE), superficial glandular (sGE), but not glandular (GE) epithelia. First, IRF2 silences transcription of the estrogen receptor alpha gene and, indirectly, transcription of the oxytocin receptor gene to abrogate development of the luteolytic mechanism to prevent regression of the corpus luteum and its production of progesterone for establishing and maintaining pregnancy. Second, IRF2 silences expression of classical interferon-stimulated genes in uterine LE and sGE; however, uterine LE and sGE respond to progesterone (P4) and IFNT to increase expression of genes for transport of nutrients into the uterine lumen such as amino acids and glucose. Other genes expressed by uterine LE and sGE encode for adhesion molecules such as galectin 15, cathepsins, and cystatins for tissue remodeling, and hypoxia-inducible factor relevant to angiogenesis and survival of blastocysts in a hypoxic environment. IFNT is also key to a servomechanism that allows uterine epithelia, particularly GE, to proliferate and to express genes in response to placental lactogen and placental growth hormone in sheep. The roles of secreted phosphoprotein 1 are also discussed regarding its role in implantation in sheep and pigs, as well as its stimulation of expression of mechanistic target of rapamycin mRNA and protein which is central to proliferation, migration, and gene expression in the trophectoderm cells.

Role of sulphate in development.

Sulphate contributes to numerous processes in mammalian physiology, particularly during development. Sulphotransferases mediate the sulphate conjugation (sulphonation) of numerous compounds, including steroids, glycosaminoglycans, proteins, neurotransmitters and xenobiotics, transforming their biological activities. Importantly, the ratio of sulphonated to unconjugated molecules plays a significant physiological role in many of the molecular events that regulate mammalian growth and development. In humans, the fetus is unable to generate its own sulphate and therefore relies on sulphate being supplied from maternal circulation via the placenta. To meet the gestational needs of the growing fetus, maternal blood sulphate concentrations double from mid-gestation. Maternal hyposulphataemia has been linked to fetal sulphate deficiency and late gestational fetal loss in mice. Disorders of sulphonation have also been linked to a number of developmental disorders in humans, including skeletal dysplasias and premature adrenarche. While recognised as an important nutrient in mammalian physiology, sulphate is largely unappreciated in clinical settings. In part, this may be due to technical challenges in measuring sulphate with standard pathology equipment and hence the limited findings of perturbed sulphate homoeostasis affecting human health. This review article is aimed at highlighting the importance of sulphate in mammalian development, with basic science research being translated through animal models and linkage to human disorders.

An evolutionary test of the isoform switching hypothesis of functional progesterone withdrawal for parturition: humans have a weaker repressive effect of PR-A than mice.

BACKGROUND: A decrease in maternal serum progesterone (P4) concentrations precedes the onset of labor in most placental mammals. Humans differ by maintaining high levels of P4 throughout birth. Parturition in humans probably includes mechanisms that undercut the pregnancy sustaining function of P4. One attractive hypothesis is the isoform switching hypothesis (ISH). ISH is supported by in vitro evidence that progesterone receptor isoform A (PR-A) inhibits PR-B and that the PR-A/PR-B ratio increases towards term. MATERIALS AND METHODS: Here, we test the hypothesis that isoform switching is an adaptation to high levels of P4 at term, predicting that, in humans, PR-A mediated repression of PR-B is stronger than in mouse. We use reporter assays with human and mouse PRs to detect species differences in the repressive effects of PR-A. RESULTS: We found that human PR-B is less sensitive to repression by human PR-A than mouse PR-B, contrary to our prediction. The difference between human and mouse PR-B sensitivity is most pronounced at PR-A/PR-B ratios typical for the preterm myometrium. CONCLUSIONS: Our results are inconsistent with the ISH. We speculate that, instead, the lower sensitivity of human PR-B to PR-A may be relevant for the maintenance of pregnancy at high progesterone levels and increasing PR-A concentrations towards term.

Antibody microarray analysis of amniotic fluid proteomes in women with cervical insufficiency and short cervix, and their association with pregnancy latency length.

INTRODUCTION: This study aimed to investigate amniotic fluid (AF) proteins that were differentially expressed between patients with cervical insufficiency (CI) and asymptomatic short cervix (SCX, ≤ 25 mm), and whether these proteins could be predictive of spontaneous preterm birth (SPTB) in these patients. METHOD: This was a retrospective cohort study of 129 singleton pregnant women with CI (n = 80) or SCX (n = 49) at 17 to 26 weeks who underwent amniocentesis. An antibody microarray was used to perform comparative proteomic profiling of AF from matched CI (n = 20) and SCX (n = 20) pregnancies. In the total cohort, an ELISA validation study was performed for 15 candidate proteins of interest. Subgroup analyses of patients with CI and SCX were conducted to evaluate the association between the 15 proteins and SPTB at < 32 weeks of gestation. RESULTS: Eighty-six proteins showed intergroup differences. ELISA validation confirmed significantly higher levels of AF EN-RAGE, IL-8, lipocalin-2, MMP-9, S100A8/A9, thrombospondin-2, and TNFR2 in patients with CI than in those with SCX. Multivariable analysis showed that increased AF levels of EN-RAGE, S100A8/A9, and uPA were independently associated with SPTB at < 32 weeks in patients with CI; whereas in patients with SCX, high AF levels of APRIL, EN-RAGE, LBP, and TNFR2 were independently associated with SPTB at < 32 weeks. CONCLUSIONS: Multiple AF proteins show altered expression in patients with CI compared with SCX controls. Moreover, several novel mediators involved in inflammation were identified as potential biomarkers for predicting SPTB after the diagnosis of CI and SCX. These results provide new insights into target-specific molecules for targeted therapies to prevent SPTB in patients with CI/SCX.

Impact of exosome-mediated feto-maternal interactions on pregnancy maintenance and development of obstetric complications.

Pregnancy is an immunological paradox, a phenomenon in which the foetus and the placenta, containing foreign antigens to the mother, develop without inducing rejection by the maternal immune system. Cell-to-cell communication between the foetus and the mother is mediated by secreted factors such as cytokines, hormones and extracellular vesicles (EVs) for a successful pregnancy and to avoid rejection. Exosomes, the smallest of EVs, are released extracellularly, where they are taken up by proximal or distant recipient cells. Here, we discuss the role of EVs, especially exosomes in feto-maternal communication during pregnancy. This review will provide an overview of the functional roles exosomes may play during embryo implantation, modulating immune responses during pregnancy and the onset of labour. Moreover, we will discuss exosomal function in obstetric pathology, and the development of pregnancy-associated complications such as preeclampsia and preterm birth as well as the biomarker potential of exosomes for detecting such conditions.

Microarray analysis of equine endometrium at days 8 and 12 of pregnancy.

Establishment and maintenance of pregnancy in equids is only partially understood. To provide new insights into early events of this process, we performed a systematic analysis of transcriptome changes in the endometrium at Days 8 and 12 of pregnancy. Endometrial biopsy samples from pregnant and nonpregnant stages were taken from the same mares. Composition of the collected biopsy samples was analyzed using quantitative stereological techniques to determine proportions of surface and glandular epithelium and blood vessels. Microarray analysis did not reveal detectable changes in gene expression at Day 8, whereas at Day 12 of pregnancy 374 differentially expressed genes were identified, 332 with higher and 42 with lower transcript levels in pregnant endometrium. Expression of selected genes was validated by quantitative real-time RT-PCR. Gene set enrichment analysis, functional annotation clustering, and cocitation analysis were performed to characterize the genes differentially expressed in Day 12 pregnant endometrium. Many known estrogen-induced genes and genes involved in regulation of estrogen signaling were found, but also genes known to be regulated by progesterone and prostaglandin E2. Additionally, differential expression of a number of genes related to angiogenesis and vascular remodeling suggests an important role of this process. Furthermore, genes that probably have conserved functions across species, such as CRYAB, ERRFI1, FGF9, IGFBP2, NR2F2, STC1, and TNFSF10, were identified. This study revealed the potential target genes and pathways of conceptus-derived estrogens, progesterone, and prostaglandin E2 in the equine endometrium probably involved in the early events of establishment and maintenance of pregnancy in the mare.

The gestational timing of pregnancy loss: adaptive strategy?

This commentary links early pregnancy milestones (rescue of the corpus luteum, the luteal-placental shift, and blocking of the spiral arteries) with the pattern of gestation-specific pregnancy loss in humans. The objective is to describe the pattern and present an adaptive hypothesis: that high first trimester pregnancy loss results from selection to reduce the risk of maternal morbidity and mortality associated with human delivery. Specific questions within the broad framework of this hypothesis can be addressed with research in comparative physiology and endocrinology.

Pharmacological use of progesterone and 17-alpha-hydroxyprogesterone caproate in the prevention of preterm delivery.

Preterm delivery (PTD) is defined by the World Health Organization as birth before 37 completed weeks of gestation. In Western countries, PTD accounts for over 75% of all perinatal morbidity and mortality. The social importance of PTD derives from the consideration that it causes near three quarter of neonatal deaths not caused by malformations. Progesterone is a steroid hormone which plays a crucial role in each step of human pregnancy. Early in pregnancy progesterone is produced by the corpus luteum and it is fundamental for pregnancy maintenance until placenta takes over this function at 7-9 weeks of gestation. Late in pregnancy, the role of progesterone is less clear: certainly, it may be importance in maintaining uterine quiescence in the latter half of pregnancy by limiting the production of stimulatory prostaglandins and inhibiting the expression of contraction-associated protein genes (ion channels, oxytocin and prostaglandin receptors, and gap junctions) within the myometrium. In this review, the authors included those controlled clinical studies that have used either 17 hydroxy progesterone caproate (17P), or progesterone (P) or its synthetic derivatives (progestins) in order to avoid or reduce the incidence of preterm delivery, in populations of women at increased risk of preterm birth. The authors conclude that: 1) the treatment with 17P reduces the incidence of PTD in pluriparous women with a previous history of PTD or with recurrent abortion, as well as in nulliparous women with an actual risk; 2) the treatment with P reduces PTD in nulliparous women, namely in the presence of a silent cervical shortening; 3) 17P has no efficacy in multiple pregnancy and it is proven not to have adverse effects on the infants.

[The relationship between inflammatory and immunological processes during pregnancy. Practical aspects]. / A gyulladásos és immunológiai folyamatok kapcsolata a várandósság alatt. Gyakorlati vonatkozások.

The aim of this review is to explore, in addition to revealing the biological background, new conceptual and therapeutic approaches for reproductive clinicians to provide better and more effective care for sterile and infertile couples. In humans, 75% of unsuccessful pregnancies are the result of failures of implantation, and implantation failure is the limiting factor for in vitro fertilization treatment. A modified "good" inflammation is necessary for implantation and parturition, but for most of pregnancy, inflammation threatens the continuation of pregnancy. During this period, maintaining the non-inflammatory condition is extremely important, enabling the maternal epigenetic effects to occur in the fetus, making it possible for the offspring to adapt as much as possible to the extrauterine life. In the maintenance of the non-inflammatory condition of pregnancy, a large amount of progesterone hormone produced by the placenta (after the luteo-placental shift) plays a crucial role. It has been reported that the role of inflammation during implantation is an ancestral response to the embryo as a foreign body. During normal pregnancy, this inflammation is initiated by the trophoblast and involves the suppression of neutrophil infiltration, the recruitment of natural killer cells to the site of implantation as well as the production of a range of proinflammatory cytokines. During the "implantation window", the uterus is primed to produce several inflammatory signals such as prostaglandin E2 and a range of proinflammatory cytokines, including TNF, IL6 and IFNγ. The feto-placental unit is a semi-foreign graft called a "semi allograft", and the recognition of pregnancy by the mother (host) and the resulting maternal immune tolerance is an essential part of successful pregnancy and the birth of a healthy fetus. Because of the functional or absolute reduction of circulating progesterone (due to the decreasing hormone production of the physiologically "aging" placenta after around the 36th week of pregnancy) progesterone effects become insufficient. Therefore it is unable to suppress the production of IL8 and other inflammatory cytokines and the term inflammation, leading to cervical ripening, uterus contractions and parturition ("good" inflammation). Orv Hetil. 2019; 160(32): 1247-1259.

Providing Patient-Centered Perinatal Care for Transgender Men and Gender-Diverse Individuals: A Collaborative Multidisciplinary Team Approach.

BACKGROUND: Little is documented about the experiences of pregnancy for transgender and gender-diverse individuals. There is scant clinical guidance for providing prepregnancy, prenatal, intrapartum, and postpartum care to transgender and gender-diverse people who desire pregnancy. CASE: Our team provided perinatal care to a 20-year-old transgender man, which prompted collaborative advocacy for health care systems change to create gender-affirming patient experiences in the perinatal health care setting. CONCLUSION: Systems-level and interpersonal-level interventions were adopted to create gender-affirming and inclusive care in and around pregnancy. Basic practices to mitigate stigma and promote gender-affirming care include staff trainings and query and use of appropriate name and pronouns in patient interactions and medical documentation. Various factors are important to consider regarding testosterone therapy for transgender individuals desiring pregnancy.

Early pregnancy loss in 15-hydroxyprostaglandin dehydrogenase knockout (15-HPGD-/-) mice due to requirement for embryo 15-HPGD activity.

Prostaglandins (PGs) have critical signaling functions in a variety of processes including the establishment and maintenance of pregnancy, and the initiation of labor. Most PGs are non-enzymatically degraded, however, the two PGs most prominently implicated in the termination of pregnancy, including the initiation of labor, prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α), are enzymatically degraded by 15-hydroxyprostaglandin dehydrogenase (15-HPGD). The role of PG metabolism by 15-HPGD in the maintenance of pregnancy remains largely unknown, as direct functional studies are lacking. To test the hypothesis that 15-PGDH-mediated PG metabolism is essential for pregnancy maintenance and normal labor timing, we generated and analyzed pregnancy in 15-HPGD knockout mice (Hpgd-/-). We report here that pregnancies resulting from matings between 15-HPGD KO mice (Hpgd-/- X Hpgd-/-KO mating) are terminated at mid gestation due to a requirement for embryo derived 15-HPGD. Aside from altered implantation site spacing, pregnancies from KO matings look grossly and histologically normal at days post coitum (dpc) 6.5 and 7.5 of pregnancy. However, virtually all of these pregnancies are resorbed by dpc 8.5. This resorption is preceded by elevation of PGF2∝ but is not preceded by a decrease in circulating progesterone, suggesting that pregnancy loss is a local inflammatory phenomenon rather than a centrally mediated phenomena. This pregnancy loss can be temporarily deferred by indomethacin treatment, but treated pregnancies are not maintained to term and indomethacin treatment increases maternal mortality. We conclude that PG metabolism to inactive products by embryo derived 15-HPGD is essential for pregnancy maintenance in mice, and may serve a similar function during human pregnancy.

Interferons and progesterone for establishment and maintenance of pregnancy: interactions among novel cell signaling pathways.

Type I and/or type II interferons (IFNs) are important in establishing uterine receptivity to implantation in mammals. Gene expression effected by IFNs may be induced, stimulated or inhibited, but most are IFN-stimulated genes (ISGs). Effects of IFNs range from pregnancy recognition signaling in ruminants by IFN tau (IFNT) to effects on cellular functions of the uterus and uterine vasculature. For most, if not all, actions of IFNs on the uterus, progesterone (P(4)) is permissive to ISG expression, with genes being induced by IFN or induced by P(4) and stimulated by IFN. Uterine receptivity to implantation is P(4)-dependent; however, implantation events are preceded by loss of expression of progesterone (PGR) and estrogen (ESR1) receptors by uterine epithelia. Thus, P4 likely stimulates PGR-positive stromal cells to express one or more progestamedins, e.g., fibroblast growth factors-7 and -10, and/or hepatocyte growth factor, that act via their respective receptors on uterine epithelia and trophectoderm to regulate expression of ISGs. FGF10 appears to be the most important progestamedin in sheep uteri during pregnancy. Sequential effects of P(4) to induce and IFNs to stimulate gene expression suggest that P(4) and IFNs activate complimentary cell signaling pathways to modulate expression of genes for attachment of trophectoderm to uterine lumenal and superficial glandular epithelia (LE/sGE), modify phenotype of uterine stromal cells, silence PGR and ESR1 genes, signal pregnancy recognition, suppress genes for immune recognition, alter membrane permeability to enhance conceptus-maternal exchange of factors, increase endometrial vascularity and activate genes for transport of nutrients into the uterine lumen. In ewes, IFNT abrogrates the uterine luteolytic mechanism and stimulates expression of classical ISGs by GE and stromal cells, whereas LE/sGE express P(4)-induced and IFNT-stimulated genes important for uterine receptivity to implantation and conceptus development. These include wingless-type MMTV (mouse mammary tumor virus) integration site family member 7A (WNT7A) induced by IFNT, as well as galectin, proteases, protease inhibitors, transporters for glucose and amino acids, gastrin releasing polypeptide, insulin-like growth factor binding protein 1 and a hypoxia inducible factor. The specific functions of IFNs and ISGs induced in primates, pigs and other mammals during pregnancy are not known, but likely are important in establishment of pregnancy. Understanding the roles of IFNs and ISGs in uterine receptivity for implantation is necessary to develop strategies to enhance reproductive health and fertility in humans and domestic animals. The magnitude of the LH surge was reduced in cows receiving endotoxin.

[Immunological role of progesterone in the maintenance of pregnancy]. / Papel inmunológico de la progesterona en el mantenimiento del embarazo.

Progesterone is an essential hormone for pregnancy maintenance. This hormone acts by binding to its intracellular receptor or by rapid non-genomic actions to regulate a wide variety of biological functions in the feto-placental unit. Progesterone regulates blastocyst implantation and placental development by inducing immunosuppression through type Th2 cytokines secretion. This review summarizes current research about the role of progesterone as critical regulator of expression and secretion of cytokines by T-cell and other placental cells.

Pregnancy, bovine somatotropin, and dietary n-3 fatty acids in lactating dairy cows: II. Endometrial gene expression related to maintenance of pregnancy.

The objectives were to examine the effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on expression of key endometrial genes and proteins regulating prostaglandin synthesis in lactating dairy cows. Two diets were fed, at about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) was compared with calcium salts of fish oil-enriched lipid (FO). Ovulation was synchronized in cows with a presynchronization plus Ovsynch protocol and cows were inseminated artificially or not inseminated on d 0 (d 0 = time of synchronized ovulation; 77 +/- 12 DIM). On d 0 and 11, cows received bST (500 mg) or no bST, and were slaughtered on d 17 to recover uterine secretions and endometrial tissue. Number of cows in the control diet: 5 bST-treated cyclic (bST-C), 5 non-bST-treated cyclic (no bST-C), 4 bST-treated pregnant (bST-P), and 5 non-bST-treated pregnant (no bST-P) cows and in the FO diet: 4 bST-treated FO-cyclic (bST-FO-C) and 5 non-bST-treated cyclic (no bST-FO-C) cows. The FO diet increased progesterone receptor (PR) mRNA, and treatment with bST increased PR mRNA concentration in endometrium of no bST-C, but not in no bST-FO-C or no bST-P cows. Concentrations of estrogen receptor-alpha (ERalpha) mRNA and protein, and oxytocin receptor (OTR) mRNA were decreased in no bST-P cows compared with no bST-C cows. Treatment with bST tended to increase OTR and ERalpha mRNA concentrations in cyclic cows fed control or FO diets. Immunohistochemistry demonstrated effects of bST, FO, and pregnancy on distributions of ERalpha and PR proteins in endometrium. Pregnancy and FO feeding decreased ERalpha abundance in luminal epithelium. Prostaglandin H synthase-2 (PGHS-2) protein was elevated in pregnant cows and localized to the luminal epithelium. Both FO and bST treatments reduced staining intensity of PGHS-2 protein. Concentrations of prostaglandin E synthase mRNA were elevated in either cyclic or pregnant cows in response to bST, whereas bST decreased prostaglandin F synthase mRNA in pregnant cows. Uterine lumen fluids had more PGF2alpha and prostaglandin E2 in pregnant than cyclic cows. Uterine lumen fluids of bST-P cows contained more prostaglandin E2 than those from no bST-P cows. In summary, both pregnancy and bST altered endometrial gene expression, and cyclic cows responded differently to bST than pregnant cows. Feeding FO modulated PR, ERalpha, and PGHS-2 expression and distribution among endometrial cell types in a manner that may favor establishment and maintenance of pregnancy.

Embryo-maternal communication during the first 4 weeks of equine pregnancy.

The first month of equine pregnancy covers a period of rapid growth and development, during which the single-cell zygote metamorphoses into an embryo with a functional circulation and precursors of many important organs, enclosed within extraembryonic membranes responsible for nutrient uptake and gaseous exchange. After exiting the oviduct, the conceptus must influence uterine physiology to ensure adequate nutrition and preparation for implantation, while continued development results in the chorioallantois superseding the yolk sac as the primary interface for maternal interaction and exchange. Throughout the first month, pregnancy maintenance depends absolutely on progesterone secreted by the primary corpus luteum. However, although extension of luteal life span via maternal recognition of pregnancy is clearly essential, it is still not known how the horse conceptus signals its presence. On the other hand, our understanding of how luteolytic prostaglandin F2α release from the endometrium is averted has improved, and we are increasingly aware of the biological and practical significance of various events characteristic of early horse pregnancy, such as selective oviductal transport, the formation and dissolution of the blastocyst capsule, and prolonged intrauterine conceptus migration. It is also increasingly clear that embryo-maternal dialog during the first month is essential not only to conceptus survival but also has more profound and long-lasting implications. In this latter respect, it is now accepted that the maternal environment (e.g., metabolic or health status) may epigenetically alter gene expression capacity of the developing embryo and thereby permanently influence the health of the resulting foal right through adulthood.