Girard, Sylvie

ABSTRACT Problem Patients with threatened preterm labor (PTL) are treated with antibiotics, corticosteroids, and magnesium sulfate to mitigate infection, promote fetal lung maturation, provide fetal neuroprotection and overall minimize the impact of prematurity on the neonate. However, the effect of these drugs on the placental inflammatory profile is unknown even though these are given systemically and reach the placenta. We evaluated their action in an ex vivo model of placental inflammation. Method of Study Placental explants from uncomplicated pregnancies were exposed to lipopolysaccharide (LPS) ± azithromycin, betamethasone, and/or magnesium sulfate. Production (lysate) and secretion (supernatant) of pro‐ and anti‐inflammatory cytokines were assessed by ELISA. Results Both pro‐ and anti‐inflammatory cytokines were increased by LPS versus untreated. Azithromycin, or magnesium sulfate did not alter the inflammatory profile by themselves nor when added at the same time or 24 h after LPS. Betamethasone decreased both pro‐ and anti‐inflammatory cytokines only when administered at the same time as LPS, without any effects if delayed. Conclusions Therapeutic interventions classically used for preterm labor (PTL) do not impact the placental inflammatory profile by themselves or in the context of an ex vivo placental explants model of LPS‐induced inflammation, except for betamethasone when administered concurrently with LPS.

Abstract. Introduction: Preterm birth drives adverse perinatal maternal and infant health outcomes through heterogeneous symptoms, severity, and etiologies. Delivery prior to reaching 37 weeks of gestation may result from medically indicated intervention for pregnancy complications or spontaneously in the absence of prior symptoms. Placental tissue collected following preterm birth exhibits differential DNA methylation compared to full-term placentas and may indicate pregnancy health during gestation. Placental DNA currently has limited utility for assessing health of ongoing pregnancy, as sampling placental tissue during gestation increases the risk of infection and miscarriage. Risks associated with placental sampling during pregnancy limit the use of DNA methylation in clinical preterm birth prediction. Assessing preterm birth risk during gestation requires non-invasive methods for characterizing placental DNA methylation. Results: We quantified genome-wide DNA methylation patterns of hypermethylated cell-free DNA in pregnant (n = 99) and non-pregnant (n = 93) plasma using cell-free methylated DNA immunoprecipitation sequencing (cfMeDIP-seq). In each sample, we assessed DNA methylation status in 300-bp genomic windows, examining both sequencing read counts and calculated absolute molar DNA amount. Known hypermethylated placental regions, including RASSF1, STAT5A, and ERG promoters showed significantly increased odds of detection in pregnant samples, suggesting enrichment of cell-free placental DNA. Of the 536,444 300-bp windows examined, 173,071 (32%) showed significant enrichment in pregnant plasma. Linear modeling identified 107,505 differentially methylated regions (DMRs) associated with pregnancies later diagnosed with intrauterine growth restriction (IUGR) (n = 22). Alu elements showed increased representation in these DMRs than expected, while other repetitive elements exhibited underrepresentation. Discussion: These results demonstrate cfMeDIP-seq's ability to enrich for cell-free placental DNA and characterize cell-free DNA methylation signatures of pregnancies complicated by IUGR. Enrichment of cell-free placental DNA enables non-invasive profiling of placental DNA methylation from maternal plasma. Detectable epigenetic signatures in maternal plasma may identify pregnancies at elevated risk for preterm birth before clinical symptoms appear. Our findings further highlight the potential of cell-free placental DNA for monitoring pregnancy health.

Background: Preeclampsia (PE) is a hypertensive disorder of pregnancy defined by new-onset hypertension occurring after 20 weeks of pregnancy, with end organ damage. Pro-inflammatory changes are also observed in these patients. Although the clinical features of PE are resolved soon after delivery, affected patients face a higher risk and earlier onset of cardiovascular disease (CVD). It is unknown what leads to this persistent elevated risk, and long-term alterations of the maternal immune system could be involved. Study objective: Our goal was to address the immune alterations and functional changes in the first year postpartum in PE as compared to normotensive (NT) pregnancies. Hypothesis: We hypothesize that the maternal immune profile is altered in the postpartum period in PE vs NT patients, with a proinflammatory bias and altered function in PE patients. Brief Statement of Methods: We prospectively followed 31 women (PE=15, NT=16) and collected blood 24 hours, and 3, 6, and 12 months postpartum. Plasma and peripheral blood mononuclear cells (PBMC) were isolated and stored for analysis. Inflammatory mediators were quantified through multiplex assays, and PBMCs profile were defined through flow cytometry as well as following inflammatory stimuli to assess their functional changes through intracellular cytokine staining and expression of activation markers. Summary of Results: PE patients had elevated CD3+ T cell frequencies at 3 and 12 months postpartum compared to NT patients. Both groups showed reduced CD14+ monocytes across postpartum timepoints compared with 24 hours. PE was also associated with increased amounts of pro-inflammatory cytokines (such as IL1α, IL9, IFNγ), chemokines and growth factors at multiple timepoints throughout the first year postpartum; NT patients had decreased amounts of pro-inflammatory cytokines. Intracellular staining showed altered immune cell functions in PE, with decreased IL-6 production following polyI:C stimulation and decreased IL-10+ monocytes after LPS and polyI:C at 3 months postpartum. At 3 months, PE patients had increased markers of activation (i.e. CD69+) in both NK cells and T cells, the latter following PMA/Ionomycin stimulation. Statement of Conclusions: Pregnancy itself induces lasting immune changes persisting to 12 months postpartum, even in NT patients, whilst PE complicated pregnancies have sustained inflammation and altered immune function in the postpartum period. Overall, this work will provide essential insight into an understudied period that many women experience and help to identify long lasting immunological changes that could impact long term maternal health. Future work will explore the impact of this sustained inflammation on epigenetic modifications in immune cells. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract SARS-CoV-2 infection disrupts iron homeostasis in organs such as the lung. Emerging evidence suggests similar dysregulation in the placenta may impair function and fetal growth. Ferroptosis, an iron-dependent form of cell death, is driven by the accumulation of labile ferrous iron, catalyzing the peroxidation of polyunsaturated fatty acids in the absence of sufficient iron storage or antioxidant defenses. This pathway has been implicated in SARS-CoV-2-related tissue damage in other organs and may contribute to placental dysfunction during pregnancy. However, the influence of infection timing, symptom severity, and fetal sex on placental iron regulation remains unexamined. We analyzed placental samples from a cohort of SARS-CoV-2-exposed pregnancies in the first (n = 6), second (n = 14), or third trimester (n = 30), classified by symptom severity (asymptomatic n = 23, symptomatic n = 27) and fetal sex, alongside unexposed controls (n = 47). We assessed placental iron deposition, lipid peroxidation, and mRNA and protein expression of ferroptosis markers. Publicly available RNA-sequencing datasets from human placenta tissue, exposed or not to SARS-CoV-2, were analyzed to assess ferroptosis-related gene expression. SARS-CoV-2 infection, particularly in symptomatic cases, was associated with reduced placental weight and birth weight. Asymptomatic cases showed increased placental iron deposition, which correlated with lower birthweight and was accompanied by elevated expression of nuclear receptor coactivator 4, a cytosolic adaptor protein that mediates the selective autophagic degradation of ferritin (ferritinophagy) and iron release. Placentas from symptomatic patients exhibited evidence of altered iron transport and sex-specific down-regulation of antioxidant defenses. Transcriptomic analyses further suggested widespread disruption of ferroptosis pathways in placentas from infected patients. Our findings reveal that SARS-CoV-2 infection alters placental iron homeostasis and is associated with ferroptosis-related changes, with distinct molecular responses based on timing of infection, symptom severity, and fetal sex.

Abstract Since the beginning of the COVID-19 pandemic, vulnerable populations such as pregnant persons have been at higher risk of severe symptoms and poor outcomes. Although reports of SARS-CoV-2 vertical transmission remain rare, several studies showed that maternal infection during pregnancy can induce histomorphological and inflammatory alterations in the placenta. However, the permissiveness of human trophoblasts to various variants of the virus remains poorly characterized. In this study, human primary villous cytotrophoblasts isolated from term placentas, along with trophoblastic cell lines BeWo, JEG-3, and HIPEC-65 were infected with the ancestral SARS-CoV-2 strain, which disseminated worldwide in early 2020. Permissiveness was assessed with quantitative RT-PCR, immunostaining of viral protein Nucleocapsid, and plaque assays. To investigate viral entry routes, cells were treated with Camostat mesylate (an inhibitor of the co-entry factor TMPRSS2) or chloroquine phosphate (an endosomal entry inhibitor) and viral fitness was assessed by plaque assays. Primary villous cytotrophoblasts and JEG-3 cells were also tested for infection with three pre-omicron SARS-CoV-2 variants of concern. Our results show that primary villous cytotrophoblasts are permissive to all tested SARS-CoV-2 strains in vitro. Infection with the ancestral SARS-CoV-2 strain relies mainly on a non-canonical endosomal entry pathway. Notably, JEG-3 cells represent an appropriate and convenient model for studying trophoblast infection by SARS-CoV-2, as they exhibit high permissiveness to the ancestral strain, and the SARS-CoV-2 entry pathway is similar to that in villous cytotrophoblasts. Overall, this study reveals that the cytotrophoblastic permissiveness to SARS-CoV-2 depends on the viral genetic nature and provides new insights into its entry route in human trophoblasts.

Abstract Description Hypertensive disorders of pregnancy (HDP) include preeclampsia (PE) and gestational hypertension (gHTN), both suspected to be immune-driven pathologies. Our data shows that both PE and gHTN involve systemic immune cell activation and increased proinflammatory cytokines however it is unclear how these immune profiles play a role in the pathogenesis of disease. We hypothesize that pregnancies complicated with HDP have dysregulated immune profiles, including hyperactive T cells which are activating the vascular endothelium. We have investigated the circulating immune profiles of patients with normotensive (NT), PE or gHTN pregnancies at the RNA, protein and cellular levels, which show significant alterations in T cells, among others. We have seen increased levels of IL-6, CXCL9 and CXCL10 in the plasma of HDP patients vs NT, suggesting the polarization and recruitment of T cells. Using cytometry by time of flight (CyTOF), we have seen changes in expression of CD11a and CXCR3 on CD4+, CD8+ and yd T cells in HDP compared to NT. Single cell RNA sequencing of CD4+ and CD8+ T cells from PE vs NT shows increased expression of genes related to pathways such as allograft rejection, angiogenesis and cytokine signaling. Our in vitro co-culture experiments examine the ability of immune cells, specifically T cells, to activate endothelial cells. These studies will address the functional contribution of T cells to endothelial activation, which is a hallmark of the hypertension seen in HDP. Topic Categories Cellular Adhesion, Migration, and Inflammation (CAM)

Abstract Description Preeclampsia (PE) is a complication of pregnancy characterized by de novo hypertension after 20 weeks of gestation with end-organ damage. Even though symptoms of PE rapidly resolve after delivery, patients have higher incidence of cardiovascular diseases in the years postpartum. Immunological changes have been observed in PE but it is unknown if these are sustained in the postpartum period. Our goal was to address the immune changes in the first year postpartum in PE as compared to normotensive (NT) as well as nulliparous women. We saw that both PE and NT pregnancies had altered immune system, especially decreased CD14+ monocytes and increased circulating pro-inflammatory cytokines when compared to nulliparous patients even one year after delivery. Furthermore, our intracellular cytokine staining analysis following stimulation suggest altered response in the postpartum period in PE with a predominant anti-inflammatory response vs NT. Overall this work suggest that the immune system remains different from nulliparous women at 1 year postpartum, even in cases of normotensive pregnancies, and is further altered following PE-complicated pregnancies. Although further analysis is ongoing, this shows that the immune system does not go back to pre-pregnancy levels in the postpartum period and that changes induced by pregnancy are at least in part sustained. We will further expand this work to address the functional changes in immune cells and the mechanisms underlying these changes. Topic Categories Mucosal and Regional Immunology (MUC)

Abstract Background and objective The placenta is crucial for fetal development; altered function is associated with complications and adverse neonatal outcomes. Our goal was to ascertain changes in the placental transcriptome in relation to neonatal outcome and fetal/placental sex. Study design Seventy-two mother-baby dyads were included. Demographic, obstetrical, neonatal, and infant health data were obtained through medical charts. Adverse neonatal outcome was defined as the presence of a pulmonary, cardiac, neurological or other health complication. Bulk RNA-sequencing of placental biopsies was obtained. P-value <0.05 was considered statistically significant. Results Neonates experiencing adverse outcomes were more likely to be premature or have lower birth weights. Analysis of the placental transcriptome revealed a predominant inflammatory profile in pregnancies associated with adverse neonatal outcomes with the top pathways being related to immune and inflammatory responses. Among differently expressed genes (DEGs), 1237 were upregulated and 239 were downregulated in adverse vs no adverse outcomes. Furthermore, sex-specific differences in gene expression were observed and indicated that male and female placentas displayed unique DEGs in association with adverse outcomes. Indeed, no DEG was observed in female placentas when comparing those without vs with adverse neonatal outcomes, as opposed to 1279 DEGs in male placentas, of which 91% were up-regulated in adverse subgroups. Conclusions These findings highlight that inflammatory pathways are upregulated in placentas in association with adverse neonatal outcomes, and showcase the importance of the fetal sex in understanding neonatal health. The placenta provides a unique tool for early identification of high-risk infants rapidly after delivery.

Abstract BACKGROUND Postpartum preeclampsia (PPPE) is a maternal condition characterized by de novo hypertension in the postpartum period with end-organ damage. We investigated the use of perinatal immune changes, through routine complete blood count (CBC), to identify high-risk individuals before PPPE development. METHODS We performed a retrospective matched case-control study of 100 individuals with PPPE, 200 term pregnancies (Ctrl) and 200 antenatal preeclampsia (PE). Detailed demographic, obstetrical, and laboratory data were retrieved from medical records. Statistical analysis was performed using one-way ANOVA, multivariate regression, and paired or unpaired t-tests, as appropriate. RESULTS Individuals who developed PPPE were significantly older and predominantly Black vs Ctrl and PE. Both PE and PPPE had higher pre-pregnancy BMI and increased personal and family history of hypertension/PE vs Ctrl (P < 0.001). Before delivery, individuals who later developed PPPE, had lower total leukocyte counts vs Ctrl (9.61 vs 10.75 × 109/L, P < 0.05) whereas monocytes percentage was elevated (8.07 vs 7.27%, P < 0.01). Comparing the postpartum/antenatal ratio in-between each condition revealed elevated leukocyte ratio in PPPE vs Ctrl (P < 0.001). The Neutrophils ratio was also increased, whereas lymphocytes and monocytes were decreased in PPPE vs both Ctrl and PE. After adjusting for race, maternal age, pre-pregnancy BMI, personal history of PE/HT, and diabetes mellitus, perinatal immune changes were still significantly associated with PPPE. CONCLUSIONS Globally, perinatal immune changes were observed in individuals with a seemingly uncomplicated pregnancy prior to the development of PPPE. This strongly supports that such changes could be used to identify high-risk individuals prior to disease onset.

Preterm premature rupture of membranes (pPROM) is a leading cause of preterm birth (PTB) and is increasingly recognized for its association with neurodevelopmental disorders (NDDs). The disruption of fetal membrane integrity introduces potential infection and inflammation into the intrauterine environment, triggering immune responses that may affect fetal development. Placental inflammation plays a pivotal role in mediating these effects, exposing the fetus to cytokines, oxidative stress, and potential microbial insults that contribute to adverse neurodevelopmental outcomes. This review examines the current evidence of the mechanistic pathways linking pPROM-induced placental inflammation to NDDs, emphasizing the roles of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) in the inflammatory responses. We discuss how these immune activations lead to immune cell recruitment and excessive (or uncontrolled) production of inflammatory mediators, leading to an overall inflammatory imbalance that has been linked to disrupted fetal brain development in animal models. Animal models provide critical insights into how both sterile and pathogenic placental inflammation alter fetal neurodevelopment, while human studies, though limited, highlight promising biomarkers and potential therapeutic targets. This review identifies critical knowledge gaps and outlines future directions to mitigate the impact of placental inflammation on long-term infant health.