BACKGROUND: Administration of antenatal steroids is standard of care for women assessed to be at imminent risk of preterm delivery. There is a marked variation in antenatal steroid dosing strategy, selection for treatment criteria, and agent choice worldwide. This, combined with very limited optimization of antenatal steroid use per se, means that treatment efficacy is highly variable, and the rate of respiratory distress syndrome is decreased to perhaps as low as 40%. In some cases, antenatal steroid use is associated with limited benefit and potential harm. OBJECTIVE: We hypothesized that individual differences in maternofetal steroid exposure would contribute to observed variability in antenatal steroid treatment efficacy. Using a chronically catheterized sheep model of pregnancy, we aimed to explore the relationship between maternofetal steroid exposure and antenatal steroid treatment efficacy as determined by functional lung maturation in preterm lambs undergoing ventilation. STUDY DESIGN: Ewes carrying a single fetus underwent surgery to catheterize a fetal and maternal jugular vein at 119 days' gestation. Animals recovered for 24 hours before being randomized to either (1) a single maternal intramuscular injection of 2 mL saline (negative control group, n=10) or (2) a single maternal intramuscular injection of 0.25 mg/kg betamethasone phosphate plus acetate (antenatal steroid group, n=20). Serial maternal and fetal plasma samples were collected from each animal after 48 hours before fetuses were delivered and ventilated for 30 minutes. Total and free plasma betamethasone concentration was measured by mass spectrometry. Fetal lung tissue was collected for analysis using quantitative polymerase chain reaction. RESULTS: One animal from the control group and one animal from the antenatal steroid group did not complete their treatment protocol and were removed from analyses. Animals in the antenatal steroid group were divided into a responder subgroup (n=12/19) and a nonresponder subgroup (n=7/19) using a cutoff of partial pressure of arterial CO2 at 30-minute ventilation within 2 standard deviations of the mean value from saline-treated negative control group animals. Although antenatal steroid improved fetal lung maturation in the undivided antenatal steroid group and in the responder subgroup both physiologically (blood gas- and ventilation-related data) and biochemically (messenger ribonucleic acid expression related to fetal lung maturation), these values did not improve relative to saline-treated control group animals in the antenatal steroid nonresponder subgroup. No differences in betamethasone distribution, clearance, or protein binding were identified between the antenatal steroid responder and nonresponder subgroups. CONCLUSION: This study correlated individual maternofetal steroid exposures with preterm lung maturation as determined by pulmonary ventilation. Herein, approximately 40% of preterm lambs exposed to antenatal steroids had lung maturation that was not significantly different to saline-treated control group animals. These nonresponsive animals received maternal and fetal betamethasone exposures identical to animals that had a significant improvement in functional lung maturation. These data suggest that the efficacy of antenatal steroid therapy is not solely determined by maternofetal drug levels and that individual fetal or maternal factors may play a role in determining treatment outcomes in response to glucocorticoid signaling.

BACKGROUND: Ex vivo uterine environment therapy is an experimental intensive care strategy for extremely preterm infants born between 21 and 24 weeks of gestation. Gas exchange is performed by membranous oxygenators connected by catheters to the umbilical vessels. The fetus is submerged in a bath of synthetic amniotic fluid. The lungs remain fluid filled, and pulmonary respiration does not occur. Intrauterine inflammation is strongly associated with extremely preterm birth and fetal injury. At present, there are no data that we are aware of to show that artificial placenta-based systems can be used to support extremely preterm fetuses compromised by exposure to intrauterine inflammation. OBJECTIVE: To evaluate the ability of our ex vivo uterine environment therapy platform to support extremely preterm ovine fetuses (95-day gestational age; approximately equivalent to 24 weeks of human gestation) exposed to intrauterine inflammation for a period of 120 hours, the following primary endpoints were chosen: (1) maintenance of key physiological variables within normal ranges, (2) absence of infection and inflammation, (3) absence of brain injury, and (4) gross fetal growth and cardiovascular function matching that of age-matched in utero controls. STUDY DESIGN: Ten ewes with singleton pregnancies were each given a single intraamniotic injection of 10-mg Escherichia coli lipopolysaccharides under ultrasound guidance 48 hours before undergoing surgical delivery for adaptation to ex vivo uterine environment therapy at 95-day gestation (term=150 days). Fetuses were adapted to ex vivo uterine environment therapy and maintained for 120 hours with constant monitoring of key vital parameters (ex vivo uterine environment group) before being killed at 100-day equivalent gestational age. Umbilical artery blood samples were regularly collected to assess blood gas data, differential counts, biochemical parameters, inflammatory markers, and microbial load to exclude infection. Ultrasound was conducted at 48 hours after intraamniotic lipopolysaccharides (before surgery) to confirm fetal viability and at the conclusion of the experiments (before euthanasia) to evaluate cardiac function. Brain injury was evaluated by gross anatomic and histopathologic investigations. Eight singleton pregnant control animals were similarly exposed to intraamniotic lipopolysaccharides at 93-day gestation and were killed at 100-day gestation to allow comparative postmortem analyses (control group). Biobanked samples from age-matched saline-treated animals served as an additional comparison group. Successful instillation of lipopolysaccharides into the amniotic fluid exposure was confirmed by amniotic fluid analysis at the time of administration and by analyzing cytokine levels in fetal plasma and amniotic fluid. Data were tested for mean differences using analysis of variance. RESULTS: Six of 8 lipopolysaccharide control group (75%) and 8 of 10 ex vivo uterine environment group fetuses (80%) successfully completed their protocols. Six of 8 ex vivo uterine environment group fetuses required dexamethasone phosphate treatment to manage profound refractory hypotension. Weight and crown-rump length were reduced in ex vivo uterine environment group fetuses at euthanasia than those in lipopolysaccharide control group fetuses (P<.05). There were no biologically significant differences in cardiac ultrasound measurement, differential leukocyte counts (P>.05), plasma tumor necrosis factor α, monocyte chemoattractant protein-1 concentrations (P>.05), or liver function tests between groups. Daily blood cultures were negative for aerobic and anaerobic growth in all ex vivo uterine environment group animals. No cases of intraventricular hemorrhage were observed. White matter injury was identified in 3 of 6 lipopolysaccharide control group fetuses and 3 of 8 vivo uterine environment group fetuses. CONCLUSION: We report the use of an artificial placenta-based system to support extremely preterm lambs compromised by exposure to intrauterine inflammation. Our data highlight key challenges (refractory hypotension, growth restriction, and white matter injury) to be overcome in the development and use of artificial placenta technology for extremely preterm infants. As such challenges seem largely absent from studies based on healthy pregnancies, additional experiments of this nature using clinically relevant model systems are essential for further development of this technology and its eventual clinical application.

BACKGROUND: Antenatal corticosteroids (ACS) are the standard of care for maturing the fetal lung and improving outcomes for preterm infants. Antenatal corticosteroid dosing remains nonoptimized, and there is little understanding of how different treatment-to-delivery intervals may affect treatment efficacy. The durability of a lung maturational response is important because the majority of women treated with antenatal corticosteroids do not deliver within the widely accepted 1- to 7-day window of treatment efficacy. OBJECTIVE: We used a sheep model to test the duration of fetal exposures for efficacy at delivery intervals from 1 to 10 days. MATERIALS AND METHODS: For infusion studies, ewes with single fetuses were randomized to receive an intravenous bolus and maintenance infusion of betamethasone phosphate to target 1-4 ng/mL fetal plasma betamethasone for 36 hours, with delivery at 2, 4 ,or 7 days posttreatment or sterile saline solution as control. Animals receiving the clinical treatment were randomised to receive either a single injection of 0.25 mg/kg with a 1:1 mixture of betamethasone phosphate + betamethasone acetate with delivery at either 1 or 7 days posttreatment, or 2 treatments of 0.25 mg/kg betamethasone phosphate + betamethasone acetate spaced at 24 hours (giving ∼48 hours of fetal steroid exposure) with delivery at 2, 5, 7, or 10 days posttreatment. Negative control animals were treated with saline solution. All lambs were delivered at 121 ± 3 days gestational age and ventilated for 30 minutes to assess lung function. RESULTS: Preterm lambs delivered at 1 or 2 days post-antenatal corticosteroid treatment had significant improvements in lung maturation for both intravenous and single-dose intramuscular treatments. After 2 days, the efficacy of 36-hour betamethasone phosphate infusions was lost. The single dose of 1:1 betamethasone phosphate + betamethasone acetate also was ineffective at 7 days. In contrast, animals treated with 2 doses had significant improvements in lung maturation at 2, 5, and 7 days, with treatment efficacy reduced by 10 days. CONCLUSION: In preterm lambs, the durability of antenatal corticosteroids treatment depends on the duration of fetal exposure and is independent of the intravenous or intramuscular maternal route of administration. For acute 24- to 48-hour posttreatment deliveries, a 24-hour fetal antenatal corticosteroids exposure was sufficient for lung maturation. A fetal exposure duration of at least 48 hours was necessary to maintain long-term treatment durability. A single-dose ACS treatment should be sufficient for women delivering within <48 hours of antenatal corticosteroids treatment.

BACKGROUND: The use of antenatal corticosteroids (ACS) in low-resource environments is sporadic. Further, drug choice, dose, and route of ACS are not optimized. We report the pharmacokinetics and pharmacodynamics of oral dosing of ACS using a preterm sheep model. METHODS: We measured pharmacokinetics of oral betamethasone-phosphate (Beta-P) and dexamethasone-phosphate (Dex-P) using catheterized pregnant sheep. We compared fetal lung maturation responses of oral Beta-P and Dex-P to the standard treatment with 2 doses of the i.m. mixture of Beta-P and betamethasone-acetate at 2, 5, and 7 days after initiation of ACS. RESULTS: Oral Dex-P had lower bioavailability than Beta-P, giving a lower maximum maternal and fetal concentration. A single oral dose of 0.33 mg/kg of Beta-P was equivalent to the standard clinical treatment assessed at 2 days; 2 doses of 0.16 mg/kg of oral Beta-P were equivalent to the standard clinical treatment at 7 days as assessed by lung mechanics and gas exchange after preterm delivery and ventilation. In contrast, oral Dex-P was ineffective because of its decreased bioavailability. CONCLUSION: Using a sheep model, we demonstrate the use of pharmacokinetics to develop oral dosing strategies for ACS. Oral dosing is feasible and may facilitate access to ACS in low-resource environments.

BACKGROUND: Ex vivo uterine environment therapy is an experimental life support platform designed to reduce the risk of morbidity and mortality for extremely preterm infants born at the border of viability (21-24 weeks' gestation). To spare the functionally immature lung, this platform performs gas exchange via a membranous oxygenator connected to the umbilical vessels, and the fetus is submerged in a protective bath of artificial amniotic fluid. We and others have demonstrated the feasibility of extended survival with ex vivo uterine environment therapy therapy in late preterm fetuses; however, there is presently no evidence to show that the use of such a platform can support extremely preterm fetuses, the eventual translational target for therapy of this nature. OBJECTIVE: The objective of the study was to use our ex vivo uterine environment therapy platform to support the healthy maintenance of 600-700 g/95 days gestational age (equivalent to 24 weeks of human gestation) sheep fetuses. Primary outcome measures were as follows: (1) maintenance of key physiological variables; (2) absence of infection; (3) absence of brain injury; and (4) growth and cardiovascular function patterns matching that of noninstrumented, age-matched in utero controls. STUDY DESIGN: Singleton fetuses from 8 ewes underwent surgical delivery at 95 days' gestation (term, 150 days). Fetuses were adapted to ex vivo uterine environment therapy and maintained for 120 hours with real-time monitoring of key physiological variables. Umbilical artery blood samples were regularly collected to assess blood gas data, differential counts, inflammation, and microbial load to exclude infection. Brain injury was evaluated by gross anatomical and histopathological approaches after euthanasia. Nine pregnant control animals were euthanized at 100 days' gestation to allow comparative postmortem analyses. Data were tested for mean differences with an analysis of variance. RESULTS: Seven of 8 ex vivo uterine environment group fetuses (87.5%) completed 120 hours of therapy with key parameters maintained in a normal physiological range. There were no significant intergroup differences (P > .05) in final weight, crown-rump length, and body weight-normalized lung and brain weights at euthanasia compared with controls. There were no biologically significant differences in hematological parameters (total or differential leucocyte counts and plasma concentration of tumor necrosis factor-α and monocyte chemoattractant protein 1) (P > .05). Daily blood cultures were negative for aerobic and anaerobic growth in all ex vivo uterine environment animals. There was no difference in airspace consolidation between control and ex vivo uterine environment animals, and there was no increase in the number of lung cells staining positive for the T-cell marker CD3. There were no increases in interleukin-1, interleukin-6, interleukin-8, tumor necrosis factor-α, and monocyte chemoattractant protein 1 mRNA expression in lung tissues compared with the control group. No cases of intraventricular hemorrhage were observed, and white matter injury was identified in only 1 ex vivo uterine environment fetus. CONCLUSION: For several decades, there has been little improvement in outcomes of extremely preterm infants born at the border of viability. In the present study, we report the use of artificial placenta technology to support, for the first time, extremely preterm ovine fetuses (equivalent to 24 weeks of human gestation) in a stable, growth-normal state for 120 hours. With additional refinement, the data generated by this study may inform a treatment option to improve outcomes for extremely preterm infants.

In brief: Preterm birth is frequently associated with antenatal corticosteroid treatment and intrauterine inflammation, yet their effect on fetal ovarian development remain largely unknown. Using a fetal sheep model, we demonstrate that these clinically relevant antenatal exposures induce distinct molecular and cellular alterations in the developing ovary, potentially compromising ovarian reserve establishment and subsequent female reproductive health. Abstract: Antenatal corticosteroid (ANS) therapy and chorioamnionitis are common antecedents of preterm birth, yet their effects on the developing fetal ovary remain poorly understood. Long-term follow-up of 45% of participants from the Auckland Steroid Trial reported that high-dose antenatal betamethasone exposure was associated with a modest delay in female reproductive maturation and a nonsignificant 2-year reduction in menopause age (Lord et al., 2025), raising concerns regarding potential effects on ovarian lifespan. Using a sheep model of pregnancy, we investigated the impact of antenatal betamethasone exposure and lipopolysaccharide-induced chorioamnionitis on fetal ovarian development. Date-mated Merino ewes were randomized to Saline Control, ANS, or chorioamnionitis treatment groups administered 2 or 8 days before delivery. Female lambs were delivered preterm at 124 ± 1 days' gestation, underwent standardized 30 min ventilation, and ovarian tissues were collected for transcriptomic and histological analyses. RNA sequencing demonstrated marked transcriptional alterations following both ANS and chorioamnionitis, affecting pathways involved in cell-cycle regulation, ovarian development, and cellular function. Histological assessment identified changes in follicle populations. Antenatal corticosteroid exposure was associated with increased markers of apoptosis, including significantly elevated terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Caspase-3 staining. Chorioamnionitis exposure resulted in significant reduction of primary follicle numbers, and trends toward increased tertiary and atretic follicles. Markers of ovarian and stromal cell populations were unchanged. Although limited by sample size and assessment of individual rather than combined exposures, these findings demonstrate that both ANS and chorioamnionitis induce acute molecular and structural changes in the developing fetal ovary, with potential implications for ovarian reserve, reproductive lifespan, and long-term female reproductive health.

Fetal hypoxia remains a major unresolved clinical challenge. Using artificial placenta (AP) technology, we established a standardized model of progressive hypoxia that induces brain injury in fetal sheep. To support the development of new antenatal monitoring strategies, we further profiled gestation-specific physiological, biochemical, protein, and cfRNA responses during progressive hypoxia. Seven fetuses at 123 days gestational age (dGA) and eight fetuses at 98 dGA (term = 150 dGA) were supported on the AP. Following a 12-h stabilization period, during which FiO₂ and gas flow to the AP oxygenator were adjusted to maintain fetal SO₂ at 65-75% and pCO₂ at 35-45 mmHg, both parameters were reduced by 5% every 30 min until termination criteria were met (arterial pH < 7.0 or base excess < -12). This protocol produced 240-300 min of progressive hypoxia. Physiological parameters, blood gases, biochemical markers, and cardiac and vascular ultrasound were assessed hourly. At the end of the experiment, brain histology and plasma cfRNA profiling were performed. Progressive hypoxia induced significant increases in pCO₂ and lactate and decreases in SO₂, CtO₂, pH, and BE in both groups (p < 0.05). Gestation-specific differences were observed in pO₂, glucose, and vital signs (heart rate, mean arterial pressure, and circuit flow). AST, ALT, and NSE rose significantly only at 123 dGA (p < 0.05), whereas S100B and NT-proBNP increased in both groups. Histology confirmed hypoxic brain injury at both gestational ages. In 123 dGA fetuses, iliac artery pulsatility index and heart rate predicted dysregulation of pH, BE, SO₂, and lactate (R2 = 0.538-0.745, p < 0.05). Plasma cfRNA analysis demonstrated distinct gestation-specific gene expression patterns consistent with hypoxia-induced injury. We developed a standardized, regulable model of fetal hypoxia and demonstrated brain injury accompanied by gestation-specific physiological, biochemical, and transcriptomic responses. Plasma cfRNA profiling highlighted its potential as an antenatal biomarker of hypoxic insult. This platform may facilitate the development of new diagnostic tools and guide evaluation of postnatal interventions.

The management and prevention of key inflammatory-associated pregnancy complications such as chorioamnionitis and pre-eclampsia is hampered by a lack of early gestation risk screening tools. In a proof-of-principle study we used targeted cell-free RNA analyses of maternal plasma samples from large animal (sheep) and human pregnancy cohorts to develop a minimally invasive screening test for inflammatory markers. This study utilised a preterm sheep model of sterile and bacterial chorioamnionitis. Date-mated ewes received either intraamniotic Saline Control (n = 10) or E.Coli LPS (Sterile chorioamnionitis) with 2 days (n = 9) or 8 days exposure(n = 6). Preterm lambs were delivered at 124 ± 1d gestation. Findings were validated in a bacterial model of chorioamnionitis where ewes were exposed to 7 days of intraamniotic M.Hominis with delivery at 98 d gestion(n = 8) or 128d gestation(n = 8). Maternal blood was collected prior to intervention and at delivery in each group. Random Forest algorithm was used to analyse 8 cell-free RNA(cfRNA) targets related to inflammation in maternal plasma at baseline and delivery, identifying genes that separated animals with or without intrauterine inflammation. Plasma cfRNA data was compared to mRNA expression in placental tissue. Haematological and placental mRNA comparisons were analysed with ANOVA/Tukey HSD/Dunnett T3 tests. Maternal plasma cfRNA findings of intrauterine inflammation were then validated in human plasma samples from a cohort of patients with late onset pre-eclampsia (n = 10) or uncomplicated pregnancies (n = 10). We present data showing that targeted maternal cfRNA assays can accurately identify chorioamnionitis of sterile (AUC 1.0) and infectious (AUC 0.84) origin in a sheep model of pregnancy. Findings were then validated in human maternal plasma samples from patients with late-onset pre-eclampsia in the 1st (AUC = 0.85), 2nd (AUC = 0.90) and 3rd (AUC = 0.82) trimesters. In both sheep and human model systems, cfRNA tests offered high levels of sensitivity and specificity in the absence of overt clinical symptoms. We suggest that further development of this technology may serve as a scalable, rapidly deployed and cost-effective means for predicting major inflammatory conditions in pregnancy.

Intrauterine inflammation is a significant cause of early preterm birth and fetal injury. There is a lack of effective interventions for intrauterine inflammation. This study aimed to determine whether direct fetal treatment with IL-1 receptor antagonists (IL-1RA), specifically anakinra (competitive IL-1RA) or rytvela (allosteric IL-1RA), could reduce intrauterine inflammation caused by intraamniotic injection of E. coli lipopolysaccharides (LPS) in a sheep model of pregnancy. We hypothesized the fetal intramuscular administration of IL1-RA therapy would comprehensively resolve intrauterine inflammation caused by LPS in the pregnant sheep model. Date-mated Merino ewes carrying single fetuses were randomized into four groups: LPS Group (10 mg intraamniotic LPS injection followed by saline), RYTVELA Group (10 mg LPS injection followed by 5 mg rytvela), ANAKINRA Group (LPS injection followed by 100 mg anakinra), and SALINE Group (saline injection followed by saline). All LPS-exposed fetuses had elevated bilirubin levels, leukopenia, and increased inflammatory mediators IL-1β, IL-8, tumour necrosis factor alpha (TNFα), and monocyte chemoattractant protein 1 (MCP-1) in amniotic fluid and lung tissue. Both anakinra and rytvela treatments reduced immunocyte infiltration in chorioamniotic membranes and lungs, and microglial staining, and increased the oligodendrocyte staining, but did not significantly resolve overall inflammation compared to the SALINE Group. In conclusion, fetal intramuscular administration of anakinra and rytvela did not effectively resolve intrauterine inflammation but showed potential in reducing tissue invasion and brain injury markers. These findings suggest that modest inflammation reduction may protect against brain injury and preterm birth, though no additional benefit was observed compared to intraamniotic IL-1RA treatment.

BACKGROUND: Antenatal steroid (ANS) therapy is given to women at risk of preterm delivery to accelerate fetal lung maturation. However, the benefit of ANS therapy is variable and how maternal and fetal factors contribute to this observed variability is unknown. We aimed to test the degree of concordance in preterm lung function, and correlate this with genomic, transcriptomic, and pharmacokinetic variables in preterm dizygotic twin ovine fetuses. METHODS: Thirty-one date-mated ewes carrying twin fetuses at 123 ± 1 days' gestation received maternal intramuscular injections of either (i) 1 × 0.25 mg/kg betamethasone phosphate and acetate (CS1, n = 11 twin pairs) or (ii) 2 × 0.25 mg/kg betamethasone phosphate and acetate, 24 h apart (CS2, n = 10 twin pairs) or (iii) 2 × saline, 24 h apart (negative control, n = 10 twin pairs). Fetuses were surgically delivered 24 h after their final treatment and ventilated for 30 min. RESULTS: ANS-exposed female fetuses had lower arterial partial pressure of carbon dioxide (PaCO2) values than male fetuses (76.5 ± 38.0 vs. 97.2 ± 42.5 mmHg), although the observed difference was not statistically significant (p = 0.1). Only 52% of ANS-treated twins were concordant for lung maturation responses. There was no difference in fetal lung tissue or plasma steroid concentrations within or between twin pairs. Genomic analysis identified 13 single-nucleotide polymorphisms (SNPs) statistically associated with ANS-responsiveness, including in the proto-oncogene MET and the transcription activator STAT1. CONCLUSIONS: Twin fetal responses and ANS tissue levels were comparable with those from singleton fetuses in earlier studies. Twin ovine fetuses thus benefit from ANS in a similar manner to singleton fetuses, and a larger dose of betamethasone is not required. Assuming no difference in input from the placental or maternal compartments, fetal lung responses to ANS therapy in dizygotic twin preterm lambs are dependent on the fetus itself. These data suggest a potential heritable role in determining ANS responsiveness.

BACKGROUND: Antenatal steroid therapy for fetal lung maturation is routinely administered to women at risk of preterm delivery. There is strong evidence to demonstrate benefit from antenatal steroids in terms of survival and respiratory disease, notably in infants delivered at or below 32 weeks' gestation. However, dosing remains unoptimized and lung benefits are highly variable. Current treatment regimens generate high-concentration, pulsatile fetal steroid exposures now associated with increased risk of childhood neurodevelopmental diseases. We hypothesized that damage-associated changes in the fetal hippocampal transcriptome would be independent of preterm lung function. METHODS: Date-mated ewes carrying a single fetus at 122 ± 2dGA (term = 150dGA) were randomized into 4 groups: (i) Saline Control Group, 4×2ml maternal saline intramuscular(IM) injections at 12hr intervals (n = 11); or (ii) Dex High Group, 2×12mg maternal IM dexamethasone phosphate injections at 12hr intervals followed by 2×2ml IM saline injections at 12hr intervals (n = 12; representing a clinical regimen used in Singapore); or (iii) Dex Low Group, 4×1.5mg maternal IM dexamethasone phosphate injections 12hr intervals (n = 12); or (iv) Beta-Acetate Group, 1×0.125mg/kg maternal IM betamethasone acetate injection followed by 3×2ml IM sterile normal saline injections 12hr intervals (n = 8). Lambs were surgically delivered 48hr after first maternal injection at 122-125dGA, ventilated for 30min to establish lung function, and euthanised for necropsy and tissue collection. RESULTS: Preterm lambs from the Dex Low and Beta-Acetate Groups had statistically and biologically significant lung function improvements (measured by gas exchange, lung compliance). Compared to the Saline Control Group, hippocampal transcriptomic data identified 879 differentially significant expressed genes (at least 1.5-fold change and FDR < 5%) in the steroid-treated groups. Pulsatile dexamethasone-only exposed groups (Dex High and Dex Low) had three common positively enriched differentially expressed pathways related in part to neurodegeneration ("Prion Disease", "Alzheimer's Disease", "Arachidonic Acid metabolism"). Adverse changes were independent of respiratory function during ventilation. CONCLUSIONS: Our data suggests that exposure to antenatal steroid therapy is an independent cause of damage- associated transcriptomic changes in the brain of preterm, fetal sheep. These data highlight an urgent need for careful reconsideration and balancing of how antenatal steroids are used, both for patient selection and dosing regimens.

Background: Antenatal steroid therapy is standard of care for women at imminent risk of preterm delivery. Current dosing regimens employ supra-pharmacological doses to achieve extended fetal steroid exposures. Objective: We aimed to determine the lowest fetal plasma betamethasone concentration sufficient to achieve functional preterm lung maturation. Study design: Ewes with singles fetuses underwent surgery to install a fetal jugular catheter. Adopting a step-wise design, ewes were randomised to either a saline-only group (Negative Control Group; n=9), or one of four betamethasone-treatment groups. Each betamethasone group fetus received a fetal intravenous infusion to target a constant plasma betamethasone levels of either: i) 2 ng/ml (2 ng/ml Positive Control Group, n=9); ii) 1 ng/ml, (1 ng/ml Group, n=10); iii) 0.5 ng/ml (0.5 ng/ml Group, n=10); or iv) 0.25 ng/ml Group (0.25 ng/ml Group, n=10). Fetuses were infused for 48 hours, delivered and ventilated. The Positive Control Group, Negative Control Group and mid-point 0.5 ng/ml Group animals were tested first. An interim analysis informed the final betamethasone group tested. Results: Positive Control Group animals had large, statistically significant improvements in respiratory function. Based on an interim analysis, the 1.0 ng/ml Group was studied in favour of the 0.25 ng/ml Group. Treatment efficacy was progressively lost at plasma betamethasone concentrations lower than 2 ng/ml. Conclusion: We demonstrated that the acute respiratory benefit conveyed by antenatal steroid exposure in the fetal sheep is progressively lost when constant fetal plasma betamethasone concentrations are reduced below a targeted value of 2 ng/ml.

INTRODUCTION: Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is important for saturated phosphatidylcholine (Sat-PC) production in the lung. Sat-PC is a critical component of pulmonary surfactant, which maintains low alveolar surface tension, facilitating respiration. Previous studies have reported an association between maternal and fetal LPCAT1 levels and neonatal lung function. Using a sheep model of pregnancy, we investigated a potential correlation between glucocorticoid-induced lung maturation and LPCAT1 mRNA and/or protein levels in the fetal lung, the placenta, the fetal plasma, and the maternal plasma. METHODS: Eighty seven single pregnant ewes received maternal intramuscular injections of betamethasone. A sub-group of five animals had both maternal and fetal catheters installed to allow for sequential sampling from both plasma compartments. Lambs were surgically delivered under terminal anaesthesia between 2 and 8 days after initial ANS treatment, at a gestational age of 121-123 days. Lambs were ventilated for 30 min to determine functional lung maturation before being euthanized for necropsy and sample collection. Fetal lung, placenta, and fetal and maternal plasma samples were used to analyse LPCAT1 gene expression and protein levels. RESULTS: The expression of LPCAT1 mRNA in the fetal lung was significantly corelated to Sat-PC levels at 8 days (R2 = 0.23, p < 0.001) and lung maturation status overall (gas exchange efficiency as determined by measurements of lamb PaCO2 during ventilation, R2 = 0.20, p < 0.001). Similarly, fetal lung LPCAT1 mRNA was also significantly correlated with the individual durability of ANS effects on fetal lung maturation (R2 = 0.20, p < 0.001). Although ANS therapy altered LPCAT1 mRNA expression in the placenta, observed changes were independent of fetal lung maturation outcomes. Neither maternal nor fetal plasma LPCAT1 levels were changed by ANS therapy over the period, including in analysis of serial maternal and fetal samples from chronically catheterised animals. DISCUSSION: LPCAT1 expression in the fetal lung was associated with the durability of glucocorticoid effects on fetal lung maturation. However, LPCAT1 expression in the placenta, the fetal plasma, and the maternal plasma was neither associated with, nor predictive of fetal lung maturation after glucocorticoid treatment in a sheep model of pregnancy.

BACKGROUND: Intraamniotic inflammation is associated with up to 40% of preterm births, most notably in deliveries occurring prior to 32 weeks' gestation. Despite this, there are few treatment options allowing the prevention of preterm birth and associated fetal injury. Recent studies have shown that the small, non-competitive allosteric interleukin (IL)-1 receptor inhibitor, rytvela, may be of use in resolving inflammation associated with preterm birth (PTB) and fetal injury. We aimed to use an extremely preterm sheep model of chorioamnionitis to investigate the anti-inflammatory efficacy of rytvela in response to established intra-amniotic (IA) lipopolysaccharide (LPS) exposure. We hypothesized that rytvela would reduce LPS-induced IA inflammation in amniotic fluid (AF) and fetal tissues. METHODS: Sheep with a single fetus at 95 days gestation (estimated fetal weight 1.0 kg) had surgery to place fetal jugular and IA catheters. Animals were recovered for 48 hours before being randomized to either: i) IA administration of 2 ml saline 24 hours before 2 ml IA and 2 ml fetal intravenous (IV) administration of saline (Saline Group, n = 7); ii) IA administration of 10 mg LPS in 2 ml saline 24 hours before 2 ml IA and 2 ml fetal IV saline (LPS Group, n = 10); 3) IA administration of 10 mg LPS in 2 ml saline 24 hours before 0.3 mg/fetal kg IA and 1 mg/fetal kg fetal IV rytvela in 2 ml saline, respectively (LPS + rytvela Group, n = 7). Serial AF samples were collected for 120 h. Inflammatory responses were characterized by quantitative polymerase chain reaction (qPCR), histology, fluorescent immunohistochemistry, enzyme-linked inmmunosorbent assay (ELISA), fluorescent western blotting and blood chemistry analysis. RESULTS: LPS-treated animals had endotoxin and AF monocyte chemoattractant protein (MCP)-1 concentrations that were significantly higher at 24 hours (immediately prior to rytvela administration) relative to values from Saline Group animals. Following rytvela administration, the average MCP-1 concentrations in the AF were significantly lower in the LPS + rytvela Group relative to in the LPS Group. In delivery samples, the expression of IL-1β in fetal skin was significantly lower in the LPS + rytvela Group compared to the LPS Group. CONCLUSION: A single dose of rytvela was associated with partial, modest inhibition in the expression of a panel of cytokines/chemokines in fetal tissues undergoing an active inflammatory response.

BACKGROUND: Labial fusion is defined as adhesions of the labia minora or majora. Labial fusion may cause urinary retention. Surgical treatment based on an accurate anatomic assessment may be needed, but the usefulness of endoscopic examination for this disease has not been reported. CASE PRESENTATION: A 76-year-old Japanese woman undergoing chemoradiation treatment for esophageal cancer was referred to our department for evaluation of high accumulation in the vagina on a positron emission tomography scan. On physical examination, her labia were noted to be extensively fused with a pinhole opening at the midline. Endoscopic examination revealed that her vagina was filled with urine and there were no abnormalities in her urethral meatus and cervix. The adhesions were separated under anesthesia and there has been no recurrence during follow-up. CONCLUSIONS: We present a case of a postmenopausal patient with labial fusion who underwent successful surgical management. An endoscopic examination enabled us to determine the precise anatomic position and adopt a safe surgical procedure.