Novel pathways of inflammation in human fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes

Vaginal host immune-microbiome-metabolite interactions associated with spontaneous preterm birth in a predominantly white cohort

In order to improve spontaneous preterm birth (sPTB) risk stratification in a predominantly white cohort of non-labouring pregnant women, we analysed their vaginal microbiota, metabolite, cytokine and foetal fibronectin (FFN) concentrations at two gestational time points (GTPs): GTP1 (20+0-22+6 weeks, preterm = 17; term = 32); and GTP2 (26+0-28+6 weeks, preterm = 14; term = 31). At GTP1, the preterm-delivered women showed abundant G. vaginalis (AUC = 0.77) over L. crispatus and L. iners, and upregulation of 10 metabolites. At GTP2, the same women had more lactobacilli- and mixed anaerobes-dominated microbiota, upregulation of five metabolites, and decreased TNFR1, distinguishing them from their term counterparts (AUC = 0.88). From GTP1 to GTP2, sPTB was associated with increased microbiota α-diversity, and upregulation of pantothenate and urate. CXCL10 declined in the term-delivered women by ~3-fold, but increased in the preterm-delivered women (AUC = 0.68), enhanced by FFN (AUC = 0.74). Characterising the complex dynamic interactions between cervicovaginal microbial metabolites and host immune responses could enhance sPTB risk stratification.

Induction of epithelial cell senescence by SERPINE1 derived from fibroblasts in the amnion at parturition

Senescence of amnion epithelial cells not only disrupts the fetal membrane structure, but also becomes a source of proinflammatory signals contributing to membrane inflammation at parturition. However, the trigger initiating their senescence awaits identification. In this study, we found that SERPINE1 abundance was significantly increased in the amnion at parturition, where SERPINE1 was found predominantly expressed in amnion fibroblasts. SERPINE1 from amnion fibroblasts induced amnion epithelial cell senescence by causing vitronectin shedding from the cells thereby interrupting the association of vitronectin with integrin subunit αV, which led to the inhibition of the cell survival-associated focal adhesion pathway. In turn, proinflammatory cytokines such as interleukin-1β from senescent amnion epithelial cells enhanced SERPINE1 expression in amnion fibroblasts, thus forming a feed-forward loop between SERPINE1 production in amnion fibroblasts and epithelial cell senescence at parturition. Studies in the pregnant mice showed that intra-amniotic injection of SERPINE1 induced preterm birth with increased cellular senescence in the fetal membranes, which could be reversed by co-administration of vitronectin. Our findings indicate that SERPINE1 derived from amnion fibroblasts participates in the induction of amnion epithelial cell senescence at parturition. Intervening in the interaction of SERPINE1 with vitronectin may have therapeutic benefit in the treatment of preterm birth.

Chorionic trophoblast cells demonstrate functionally different phenotypes from placental trophoblasts†

Chorionic trophoblast cells are one of the principal components of the fetal membrane and join with the decidua to form a feto-maternal interface. Recent success in isolating chorionic trophoblast cells dealt with two separate questions: (i) the necessity of highly enriched and defined media with inhibitors of oxidative stress and cell transition and their impact on growth and trophoblast phenotype, (ii) the functional differences between chorionic trophoblast cells and other placental trophoblast lineages of cells (placental cytotrophoblast cells, and extravillous trophoblast). Chorionic trophoblast cells were cultured either in defined media with various inhibitors or in media from which inhibitors were removed individually. Cellular morphology and growth (microscopy and crystal violet staining) and cellular and molecular biological features (immunofluorescence staining for GATA-binding protein 3, cytokeratin 7, and vimentin) were assessed. Syncytialization of cells (forskolin treatment) and invasive properties of chorionic trophoblast cells (cell invasion assay) were tested and compared with placental cytotrophoblast cells and extravillous trophoblasts (HTR8/SVneo), respectively. Removal of various growth-supporting agents from the media delayed cell growth and inclined towards cellular transition (increase in vimentin compared to cytokeratin 7 or GATA-binding protein 3) compared to chorionic trophoblast cells grown in complete and enriched media. The chorionic trophoblast cells failed to syncytialize, contrasting with the high levels of membrane fusion observed in placental cytotrophoblast cells. Although chorionic trophoblast cells express human leukocyte antigen G like extravillous trophoblasts, they do not invade. Chorionic trophoblast cells require several specific constituents for in vitro growth and phenotype maintenance. Chorionic trophoblast cells are trophoblast lineage cells that barricade immune cell-enriched decidua without invading them. These properties support their location and function, which are distinct from placental cytotrophoblast cells and extravillous trophoblasts.

Determining Sex-Specific Gene Expression Differences in Human Chorion Trophoblast Cells

Differences in male (M) and female (F) neonates' premature birth outcomes and placental trophoblast inflammation have been observed but are unknown to occur within the fetal membrane trophoblast layer (chorion trophoblasts [CTC]). This study examined whether sex-based differences in gene expression and inflammatory marker expression can be observed in CTCs under control or infectious inflammatory conditions modeling preterm birth. CTCs from six different patient-derived fetal membrane samples (3M/3F) were cultured and divided into experimental (Lipopolysaccharide [LPS]) and control groups for 6, 12, or 24 h. RNA from CTCs was subjected to RNA-seq, while cytokine multiplex or ELISA detected pro-/anti-inflammatory cytokines, progesterone, and soluble HLA-G in cell supernatants. CTC-M and CTC-F showed sex, time, and stimulant-dependent differential gene expression profiles. Cytokine analysis demonstrated a significantly lower IL-6 production in control CTC-M than in CTC-F. No sex-dependent responses were observed after LPS treatment regarding cytokines. CTC-M produced significantly lower progesterone than CTC-F. The theories of sexual dimorphism linked to placental inflammation may not extend to CTCs. This study supports that the chorion acts as a "great wall" protecting the fetus by being refractory to insults. Further examination into the weaknesses of the chorion barrier and sex-dependent responses of fetal membranes is needed.

Management of cervical cerclage after preterm premature rupture of membranes: an argument for retention

Preterm birth remains the leading cause of infant morbidity and mortality worldwide. Efforts aimed at reducing preterm birth rates have largely focused on mitigating risks in those who have already experienced a preterm delivery. Of note, 1 intervention, the placement of a cervical cerclage, has been shown to reduce the risk of subsequent preterm delivery in appropriate candidates. However, a cerclage does not mitigate the risk of preterm premature rupture of membranes. Preterm premature rupture of membranes is a significant contributor to the incidence of preterm births and can occur with a cerclage in place. Many studies have examined the outcomes associated with immediate vs delayed cerclage removal after preterm premature rupture of membranes with inconsistent results. This expert review summarized the characteristics of the studies examining the timing of cerclage removal after preterm premature rupture of membranes (Table 1) and current international guidelines (Table 2). In the absence of labor, infection, cervical laceration, or vaginal bleeding, it is recommended that cervical cerclage remains in situ after preterm premature rupture of membranes until 32 to 34 weeks of gestation.

Do progesterone receptor membrane components (PGRMC)s play a role in the chorions refractoriness to epithelial-to-mesenchymal transition (EMT)?

Fetal membrane inflammation is one of the drivers of adverse pregnancy outcomes. One of the reported pathways of inflammation is epithelial-mesenchymal transition (EMT) of amniotic epithelial cells. EMT is resisted during gestation via signaling initiated by the binding of progesterone (P4) to progesterone receptor membrane components (PGRMC1/PGRMC2). The vulnerability of chorionic trophoblast cells (CTCs) to transition has not been studied. Here, we examined CTCs EMT in response to the stressors and the role of PGRMC1/PGRMC2. CTCs were treated with the autophagy inhibitor bafilomycin (Baf), transforming growth factor beta (TGF-β, EMT-inducer), and lipopolysaccharide (LPS) to simulate cellular stressors associated with an adverse pregnancy environment. The primary endpoints included morphological evidence of EMT, N-cadherin-to-E-cadherin ratio, vimentin/cytokeratin staining, pro-inflammatory cytokine and P4 production. PGRMC1/PGRMC2 knock-out (KO) CTCs were prepared using CRISPR/Cas9, and experiments were repeated to test the influence of the P4-PGRMC axis. Wild-type CTCs were resistant to cellular transitions, changes in P4 production, and shifts in the inflammatory status under normal, LPS, or TGF-β conditions. Autophagy inhibition tended to cause CTCs to transition (morphological changes; high N-cadherin-to-E-cadherin ratio [p < 0.05], no change in vimentin/cytokeratin), though a complete transition was not evident. Further, neither PGRMC1/PGRMC2 played a role in CTC cellular transitions, as their KO did not cause any major changes. Chorion cells resist EMT to minimize inflammation and to maintain their barrier functions regardless of the presence of PGRMC1/ PGRMC2. Cellular stressors or infectious antigens are likely to impact the amnion, where membrane weakening can be initiated.

Role of E-cadherin in epithelial barrier dysfunction: implications for bacterial infection, inflammation, and disease pathogenesis

Epithelial barriers serve as critical defense lines against microbial infiltration and maintain tissue homeostasis. E-cadherin, an essential component of adherens junctions, has emerged as a pivotal molecule that secures epithelial homeostasis. Lately, its pleiotropic role beyond barrier function, including its involvement in immune responses, has become more evident. Herein, we delve into the intricate relationship between (dys)regulation of epithelial homeostasis and the versatile functionality of E-cadherin, describing complex mechanisms that underlie barrier integrity and disruption in disease pathogenesis such as bacterial infection and inflammation, among others. Clinical implications of E-cadherin perturbations in host pathophysiology are emphasized; downregulation, proteolytic phenomena, abnormal localization/signaling and aberrant immune reactions are linked with a broad spectrum of pathology beyond infectious diseases. Finally, potential therapeutic interventions that may harness E-cadherin to mitigate barrier-associated tissue damage are explored. Overall, this review highlights the crucial role of E-cadherin in systemic health, offering insights that could pave the way for strategies to reinforce/restore barrier integrity and treat related diseases.

High rates of placental inflammation among samples collected by the Multi-Omics for Mothers and Infants consortium

BACKGROUND

The Multi-Omics for Mothers and Infants consortium aims to improve birth outcomes. Preterm birth is a major obstetrical complication globally and causes significant infant and childhood morbidity and mortality.

OBJECTIVE

We analyzed placental samples (basal plate, placenta or chorionic villi, and the chorionic plate) collected by the 5 Multi-Omics for Mothers and Infants sites, namely The Alliance for Maternal and Newborn Health Improvement Bangladesh, The Alliance for Maternal and Newborn Health Improvement Pakistan, The Alliance for Maternal and Newborn Health Improvement Tanzania, The Global Alliance to Prevent Prematurity and Stillbirth Bangladesh, and The Global Alliance to Prevent Prematurity and Stillbirth Zambia. The goal was to analyze the morphology and gene expression of samples collected from preterm and uncomplicated term births.

STUDY DESIGN

The teams provided biopsies from 166 singleton preterm (<37 weeks' gestation) and 175 term (≥37 weeks' gestation) deliveries. The samples were fixed in formalin and paraffin embedded. Tissue sections from these samples were stained with hematoxylin and eosin and subjected to morphologic analyses. Other placental biopsies (n=35 preterm, 21 term) were flash frozen, which enabled RNA purification for bulk transcriptomics.

RESULTS

The morphologic analyses revealed a surprisingly high rate of inflammation that involved the basal plate, placenta or chorionic villi, and the chorionic plate. The rate of inflammation in chorionic villus samples, likely attributable to chronic villitis, ranged from 25% (Pakistan site) to 60% (Zambia site) of cases. Leukocyte infiltration in this location vs in the basal plate or chorionic plate correlated with preterm birth. Our transcriptomic analyses identified 267 genes that were differentially expressed between placentas from preterm vs those from term births (123 upregulated, 144 downregulated). Mapping the differentially expressed genes onto single-cell RNA sequencing data from human placentas suggested that all the component cell types, either singly or in subsets, contributed to the observed dysregulation. Consistent with the histopathologic findings, gene ontology analyses highlighted the presence of leukocyte infiltration or activation and inflammatory responses in both the fetal and maternal compartments.

CONCLUSION

The relationship between placental inflammation and preterm birth is appreciated in developed countries. In this study, we showed that this link also exists in developing geographies. In addition, among the participating sites, we found geographic- and population-based differences in placental inflammation and preterm birth, suggesting the importance of local factors.

Predictors of Inflammation-Mediated Preterm Birth

Preterm birth remains a worldwide health concern because of ongoing challenges in prediction and prevention. Current predictors are limited by poor performance, need for invasive sampling, and an inability to identify patients in a timely fashion to allow for effective intervention. The multiple etiologies of preterm birth often have an inflammatory component. Thus, a deeper understanding of the inflammatory mechanisms involved in preterm birth may provide opportunities to identify new predictors of preterm birth. This review discusses the multiple etiologies of preterm birth, their links to inflammation, current predictors available, and new directions for the field.

Molecular profiling unveils pyroptosis markers in preterm birth

Through a comprehensive examination of pyroptosis-related differential expressed genes (PRDEGs), this work investigates the molecular complexities of spontaneous preterm birth (SPTB), also known as premature delivery, before the due date. Through the process of merging and correcting batch effects in the GSE120480 and GSE73714 datasets, we were able to identify 36 PRDEGs that exhibited significant expression differentiation in SPTB. Through functional enrichment and pathway analysis, their importance in amino acid transport and cytokine receptor interaction has been highlighted. Among the genes that have emerged as crucial, CEBPA, APOA1, and CEP55 have been identified. The relevance of these molecules was demonstrated using experimental knockdowns, which also suggested that they could be used as molecular biomarkers and therapeutic targets for SPTB.

miR-548az-5p induces amniotic epithelial cell senescence by regulating KATNAL1 expression in labor

Amniotic fluid exosomes (AF-Exos) from term labor (TL) cause amniotic membrane senescence and induce labor. However, the intrinsic mechanism through which this occurs remains unknown. Therefore, we performed microRNA (miRNA) microarray chip screening of AF-Exos obtained from TL and terms not in labor and discovered that the expression of miR-548az-5p was significantly upregulated in TL. This study aimed to explore the role of miR-548az-5p in AF-Exos-induced human amniotic epithelial cells (hAECs) senescence for labor initiation. Bioinformatics analysis revealed that Katanin catalytic subunit A1 like 1 (KATNAL1) is a potential miR-548az-5p target. In hAECs, the upregulation of miR-548az-5p suppressed KATNAL1 expression, disorganized microtubules, increased senescence-associated secretory phenotype-related biomarkers, and inhibited cell proliferation by cyclin D1 and cyclin-dependent kinase 6 (CDK6). This study identified that miR-548az-5p is involved in the senescence of amniotic epithelial cells by targeting KATNAL1 to induce labor. Notably, this study offers new perspectives on the mediation of cellular senescence using AF-Exos miRNAs, which results in labor.

Characterization of Amniotic Fluid Ureaplasma Species from Pregnancies Complicated by Preterm Prelabor Rupture of Membranes

The main aim of this study was to determine expanded sequence types (eSTs) of Ureaplasma species (U. spp.). DNA isolated from the amniotic fluid of pregnancies complicated by preterm prelabor rupture of membranes (PPROM) using an expanded multilocus sequence typing scheme. Additionally, the study sought to examine whether phylogenetic subgroups of U. spp. DNA differ with respect to maternal demographic and clinical parameters and selected aspects of short-term neonatal morbidity. This retrospective cohort study was focused on singleton pregnancies complicated by PPROM occurring between the gestational ages of 24+0 and 36+6 weeks, where amniocentesis was conducted to assess the intra-amniotic environment and the presence of U. spp. DNA in the amniotic fluid samples was confirmed. The stored aliquots of U. spp. DNA were used to assess differences in nucleotide sequences in six U. spp. genes (ftsH, rpL22, valS, thrS,ureG, and mba-np1) using the eMLST scheme. The expanded multilocus sequence typing scheme was performed in 73 samples of U. spp. DNA isolated from pregnancies complicated by PPROM. In total, 33 different U. spp. DNA eSTs were revealed, 21 (#20, 233-244, 248-251, 253, 255, 259, and 262) of which were novel. The most frequently identified eST was #41, identified in 18% (13/73) of the aliquots. Based on their genetic relationships, the U. spp. DNA was divided into two clusters and four subgroups [cluster I (U. parvum): A, 43% (n = 31); B, 15% (n = 11); and C, 26% (n = 19); cluster II (U. urealyticum): 1; 16% (n = 12)]. Cluster II had a higher rate of polymicrobial findings than cluster I (58% vs 16%; p = 0.005), while subgroup A had the highest rate of concomitant Mycoplasma hominis in the amniotic fluid samples (66%; p = 0.04). In conclusion, Ureaplasma spp. DNA obtained from PPROM consisted of 33 different eSTs of U. spp. DNA. No differences in maternal and neonatal characteristics were found among the phylogenetical subgroups of U. spp. DNA, except for a higher rate of polymicrobial amniotic fluid findings in those with U. urealyticumand the concomitant presence of M. hominis in the amniotic fluid in those with the presence of U. parvum.

Galectin-1 Elicits a Tissue-Specific Anti-Inflammatory and Anti-Degradative Effect Upon LPS-Induced Response in an Ex Vivo Model of Human Fetal Membranes Modeling an Intraamniotic Inflammation

PROBLEM

Intrauterine infection is one of the most jeopardizing conditions associated with adverse outcomes, including preterm birth; however, multiple tolerance mechanisms operate at the maternal-fetal interface to avoid the rejection of the fetus. Among the factors that maintain the uterus as an immunoprivileged site, Galectin-1 (Gal-1), an immunomodulatory glycan-binding protein secreted by the maternal-fetal unit, is pivotal in promoting immune cell homeostasis. This work aimed to evaluate the role of Gal-1 during a lipopolysaccharide (LPS)-induced-inflammatory milieu.

METHOD OF STUDY

Using an ex vivo culture with two independent compartments, human fetal membranes at term were pretreated with 40 and 80 ng/mL of Gal-1, then to reproduce an intraamniotic inflammation, the fetal side of membranes was stimulated with 500 ng/mL of LPS for 24 h. The concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, monocyte chemoattractant protein (MCP1), macrophage inflammatory protein (MIP1) α, regulated upon activation normal T cell expressed and secreted (RANTES), and matrix metalloproteinase (MMP)-9 were measured in both amnion and choriodecidua compartments.

RESULTS

In a tissue-specific fashion profile, pretreatment with the physiologic concentration of Gal-1 significantly diminished the LPS-dependent secretion of TNF-α, IL-1β, Il-6, MCP1, MIP1α, RANTES, and MMP-9.

CONCLUSION

Gal-1 elicits an anti-inflammatory effect on the human fetal membranes stimulated with LPS, which supports the hypothesis that Gal-1 is part of the immunomodulatory mechanisms intended to stop the harmful effect of inflammation of the maternal-fetal interface.

C/EBPδ deficiency delays infection-induced preterm birth

BACKGROUND

Parturition is an inflammation process. Exaggerated inflammatory reactions in infection lead to preterm birth. Although nuclear factor kappa B (NF-κB) has been recognized as a classical transcription factor mediating inflammatory reactions, those mediated by NF-κB per se are relatively short-lived. Therefore, there may be other transcription factors involved to sustain NF-κB-initiated inflammatory reactions in gestational tissues in infection-induced preterm birth.

METHODS

Cebpd-deficient mice were generated to investigate the role of CCAAT enhancer-binding protein δ (C/EBPδ) in lipopolysaccharide (LPS)-induced preterm birth, and the contribution of fetal and maternal C/EBPδ was further dissected by transferring Cebpd-/- or WT embryos to Cebpd-/- or WT dams. The effects of C/EBPδ pertinent to parturition were investigated in mouse and human myometrial and amnion cells. The interplay between C/EBPδ and NF-κB was examined in cultured human amnion fibroblasts.

RESULTS

The mouse study showed that LPS-induced preterm birth was delayed by Cebpd deficiency in either the fetus or the dam, with further delay being observed in conceptions where both the dam and the fetus were deficient in Cebpd. Mouse and human studies showed that the abundance of C/EBPδ was significantly increased in the myometrium and fetal membranes in infection-induced preterm birth. Furthermore, C/EBPδ participated in LPS-induced upregulation of pro-inflammatory cytokines as well as genes pertinent to myometrial contractility and fetal membrane activation in the myometrium and amnion respectively. A mechanistic study in human amnion fibroblasts showed that C/EBPδ, upon induction by NF-κB, could serve as a supplementary transcription factor to NF-κB to sustain the expression of genes pertinent to parturition.

CONCLUSIONS

C/EBPδ is a transcription factor to sustain the expression of gene initiated by NF-κB in the myometrium and fetal membranes in infection-induced preterm birth. Targeting C/EBPδ may be of therapeutic value in the treatment of infection-induced preterm birth.

Hsa-miR-3928-3p targets the CCL3/CCR5 axis to induce amniotic epithelial cell senescence involved in labor initiation

INTRODUCTION

Senescence in human amniotic epithelial cells (hAECs) and increased sterile inflammation in the amniotic cavity can lead to the initiation of term labor (TL). We investigated the possible roles of hsa-miR-3928-3p and chemokine ligand 3 (CCL3) in labor initiation and the underlying molecular mechanisms.

METHODS

Microarray chip screening was used to analyse the differential expression of miRNAs in amniotic fluid exosomes from women in TL and term not-in-labor. The GEO and miRWalk databases were used to identify differential genes, and a dual luciferase assay was used to verify the relationship. Reverse transcription quantitative PCR (RT-qPCR) and immunofluorescence were used to determine the expression and localization of CCL3/CCR5 in fetal membranes. RT-qPCR and western blotting were used to detect the expression of CCL3/CCR5 in hAECs with hsa-miR-3928-3p knockdown/overexpression. Cell counting kit 8, flow cytometry, EdU proliferation, senescence-associated β-galactosidase, and enzyme-linked immunosorbent assays were performed to detect the impact of hsa-miR-3928-3p on hAEC function.

RESULTS

hsa-miR-3928-3p expression was downregulated in TL. CCL3 (macrophage inflammatory protein-1α) was identified as a differentially expressed target gene. hsa-miR-3928-3p targeted the 3' UTR of CCL3. Downregulation of hsa-miR-3928-3p expression increased CCL3 expression. CCL3, via its CCR5 receptor, decreased the proliferation, but increased the senescence, apoptosis rate, secretion of inflammatory factors (IL-8, TNF-α, and IL-6), and expression of senescence-associated protein p21 in hAECs.

DISCUSSION

hsa-miR-3928-3p negatively regulates CCL3, promoting hAEC senescence through the CCL3-CCR5 axis and inducing signals for labor initiation. These findings provide novel insights for labor initiation in clinical settings.

The dual role of glucocorticoid regeneration in inflammation at parturition

Introduction

Fetal membrane inflammation is an integral event of parturition. However, excessive pro-inflammatory cytokines can impose threats to the fetus. Coincidentally, the fetal membranes express abundant 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), which generates biologically active cortisol to promote labor through induction of prostaglandin synthesis. Given the well-recognized anti-inflammatory actions of glucocorticoids, we hypothesized that cortisol regenerated in the fetal membranes might be engaged in restraining fetus-hazardous pro-inflammatory cytokine production for the safety of the fetus, while reserving pro-labor effect on prostaglandin synthesis to ensure safe delivery of the fetus.

Methods

The hypothesis was examined in human amnion tissue and cultured primary human amnion fibroblasts as well as a mouse model.

Results

11β-HSD1 was significantly increased in the human amnion in infection-induced preterm birth. Studies in human amnion fibroblasts showed that lipopolysaccharide (LPS) induced 11β-HSD1 expression synergistically with cortisol. Cortisol completely blocked NF-κB-mediated pro-inflammatory cytokine expression by LPS, but STAT3-mediated cyclooxygenase 2 expression, a crucial prostaglandin synthetic enzyme, remained. Further studies in pregnant mice showed that corticosterone did not delay LPS-induced preterm birth, but alleviated LPS-induced fetal organ damages, along with increased 11β-HSD1, cyclooxygenase 2, and decreased pro-inflammatory cytokine in the fetal membranes.

Discussion

There is a feed-forward cortisol regeneration in the fetal membranes in infection, and cortisol regenerated restrains pro-inflammatory cytokine expression, while reserves pro-labor effect on prostaglandin synthesis. This dual role of cortisol regeneration can prevent excessive pro-inflammatory cytokine production, while ensure in-time delivery for the safety of the fetus.

New therapeutic target NCF1-directed multi-bioactive conjugate therapies prevent preterm birth and adverse pregnancy outcomes

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality worldwide, yet the cellular and molecular mechanisms driving this condition remain undeciphered, thus limiting discovery of new therapies. In-depth analyses of human and mouse tissues associated with PTB, in combination with cellular studies, indicated that aberrantly high-expressed neutrophil cytoplasmic factor (NCF) 1 leads to oxidative distress, recruitment, and pro-inflammatory activation of neutrophils and macrophages, while sequentially overexpressed pro-inflammatory mediators induce contractions of uterine smooth muscle cells (USMCs) as well as apoptosis of USMCs and amniotic epithelial cells, thereby causing PTB. According to these new findings, we rationally engineered an amphiphilic macromolecular conjugate LPA by covalently integrating low-molecular-weight heparin, a reactive oxygen species-responsive/scavenging component, and an anti-inflammatory peptide. This bioengineered macromolecular conjugate can self-assemble into multi-bioactive nanoparticles (LPA NP). In a mouse model of PTB, LPA NP effectively delayed PTB and inhibited adverse pregnancy outcomes, by regulating NCF1-mediated oxidative-inflammatory cascades, i.e., attenuating oxidative stress, inhibiting inflammatory cell activation, reducing local inflammation, and decreasing contraction/apoptosis of myometrial cells. Packaging LPA NP into temperature-responsive, self-healing, and bioadhesive hydrogel further potentiated its in vivo efficacies after intravaginal delivery, by prolonging retention time, sustaining nanotherapy release, and increasing bioavailability in the placenta/uterus. Importantly, both the conjugate/nanotherapy and hydrogel formulations exhibited excellent safety profiles in pregnant mice, with negligible side effects on the mother and offspring.

PGRMC2 and HLA-G regulate immune homeostasis in a microphysiological model of human maternal-fetal membrane interface

Chorion trophoblasts (CTCs) and immune cell-enriched decidua (DECs) comprise the maternal-fetal membrane interface called the chorio-decidual interface (CDi) which constantly gets exposed to maternal stressors without leading to labor activation. This study explored how CTCs act as a barrier at CDi. The roles of human leukocyte antigen (HLA)-G and progesterone receptor membrane component 2 (PGRMC2) in mediating immune homeostasis were also investigated. The CDi was recreated in a two-chamber microfluidic device (CDi-on-chip) with an outer chamber of primary DECs and immune cell line-derived innate immune cells and an inner chamber of wild-type or PGRMC2 or HLA-G knockout immortalized CTCs. To mimic maternal insults, DECs were treated with lipopolysaccharide, poly(I:C), or oxidative stress inducer cigarette smoke extract. Expression levels of inflammation and immunity genes via targeted RNA sequencing, production of soluble mediators, and immune cell migration into CTCs were determined. In CDi-on-chip, decidua and immune cells became inflammatory in response to insults while CTCs were refractory, highlighting their barrier function. HLA-G and PGRMC2 are found to be vital to immune homeostasis at the CDi, with PGRMC2 serving as an upstream regulator of inflammation, HLA-G expression, and mesenchymal-epithelial transition, and HLA-G serving as a frontline immunomodulatory molecule, thus preventing fetal membrane compromise.

High-Throughput 3D-Printed Model of the Feto-Maternal Interface for the Discovery and Development of Preterm Birth Therapies

Spontaneous preterm birth (PTB) affects around 11% of births, posing significant risks to neonatal health due to the inflammation at the fetal-maternal interface (FMi). This inflammation disrupts immune tolerance during pregnancy, often leading to PTB. While organ-on-a-chip (OOC) devices effectively mimic the physiology, pathophysiology, and responses of FMi, their relatively low throughput limits their utility in high-throughput testing applications. To overcome this, we developed a three-dimensional (3D)-printed model that fits in a well of a 96-well plate and can be mass-produced while also accurately replicating FMi, enabling efficient screening of drugs targeting FMi inflammation. Our model features two cell culture chambers (maternal and fetal cells) interlinked via an array of microfluidic channels. It was thoroughly validated, ensuring cell viability, metabolic activity, and cell-specific markers. The maternal chamber was exposed to lipopolysaccharides (LPS) to induce an inflammatory state, and proinflammatory cytokines in the culture supernatant were quantified. Furthermore, the efficacy of anti-inflammatory inhibitors in mitigating LPS-induced inflammation was investigated. Results demonstrated that our model supports robust cell growth, maintains viability, and accurately mimics PTB-associated inflammation. This high-throughput 3D-printed model offers a versatile platform for drug screening, promising advancements in drug discovery and PTB prevention.

Unveiling the human fetal-maternal interface during the first trimester: biophysical knowledge and gaps

The intricate interplay between the developing placenta and fetal-maternal interactions is critical for pregnancy outcomes. Despite advancements, gaps persist in understanding biomechanics, transport processes, and blood circulation parameters, all of which are crucial for safe pregnancies. Moreover, the complexity of fetal-maternal interactions led to conflicting data and methodological variations. This review presents a comprehensive overview of current knowledge on fetal-maternal interface structures, with a particular focus on the first trimester. More in detail, the embryological development, structural characteristics, and physiological functions of placental chorionic plate and villi, fetal membranes and umbilical cord are discussed. Furthermore, a description of the main structures and features of maternal and fetal fluid dynamic exchanges is provided. However, ethical constraints and technological limitations pose still challenges to studying early placental development directly, which calls for sophisticated in vitro, microfluidic organotypic models for advancing our understanding. For this, knowledge about key in vivo parameters are necessary for their design. In this scenario, the integration of data from later gestational stages and mathematical/computational simulations have proven to be useful tools. Notwithstanding, further research into cellular and molecular mechanisms at the fetal-maternal interface is essential for enhancing prenatal care and improving maternal and fetal health outcomes.

The Role of Prolactin in Amniotic Membrane Regeneration: Therapeutic Potential for Premature Rupture of Membranes

Premature rupture of membranes (PROM) is defined as rupture of fetal membranes before the onset of labor. Prolactin (PRL) is secreted by decidual membranes and accumulated significantly in the amniotic fluid during pregnancy. PRL could ameliorate inflammation and collagen degradation in fetal membranes. However, the role of PRL in amniotic membrane is not well characterized. We isolated human amniotic epithelial stem cells (hAESCs) from human fetal membranes to study the effect of PRL on proliferation, migration, and antioxidative stress. Amniotic pore culture technique (APCT) model was constructed to evaluate the tissue regeneration effect in vitro. The potential targets and pathways of PRL acting in amnion via integrated bioinformatic methods. PRL had a dose-dependent effect on hAESCs in vitro. PRL (500 ng/mL) significantly improved the viability of hAESCs and inhibited cell apoptosis, related to the upregulation of CCN2 expression and downregulation of Bax, Caspase 3, and Caspase 8. PRL accelerated migration process in hAESCs via downregulation of MMP2, MMP3, and MMP9. PRL attenuated the cellular damage and mitochondrial dysfunction induced by hydrogen peroxide in hAESCs. PRL accelerated the healing process in the APCT model significantly. The top 10 specific targets (IGF1R, SIRT1, MAP2K1, CASP8, MAPK14, MCL1, NFKB1, HIF1A, MTOR, and HSP90AA1) and signaling pathways (such as HIF signaling pathway) were selected using an integrated bioinformatics approach. PRL improves the viability and antioxidative stress function of hAESCs and the regeneration of ruptured amniotic membranes in vitro. Thus, PRL has great therapeutic potential for prevention and treatment of ruptured membranes.

Role of Platelet Activating Factor as a Mediator of Inflammatory Diseases and Preterm Delivery

Nearly 70% of preterm deliveries occur spontaneously, and the clinical pathways involved include preterm labor and preterm premature rupture of membranes. Prediction of preterm delivery is considered crucial due to the significant effects of preterm birth on health and the economy at both the personal and community levels. Although similar inflammatory processes occur in both term and preterm delivery, the premature activation of these processes or exaggerated inflammatory response triggered by infection or sterile factors leads to preterm delivery. Platelet activating factor (PAF) is a phosphoglycerylether lipid mediator of inflammation that is implicated in infections, cancers, and various chronic diseases and disorders including cardiovascular, renal, cerebrovascular, and central nervous system diseases. In gestational tissues, PAF mediates the inflammatory pathways that stimulate the effector mechanisms of labor, including myometrial contraction, cervical dilation, and fetal membrane rupture. Women with preterm labor and preterm premature rupture of membranes have increased levels of PAF in their amniotic fluid. In mice, the intrauterine or intraperitoneal administration of carbamyl PAF activates inflammation in gestational tissues, thereby eliciting preterm delivery. This review summarizes recent research on PAF as an important inflammatory mediator in preterm delivery and in other inflammatory disorders, highlighting its potential value for prediction, intervention, and prevention of these diseases.

Angiogenic imbalance in pregnancies with preterm prelabor rupture of membranes between 34 and 37 weeks of gestation

INTRODUCTION

This study aimed to identify whether microbial invasion of the amniotic cavity and/or intra-amniotic inflammation in women with late preterm prelabor rupture of membranes (PPROM) was associated with changes in concentrations of soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF) and its ratio in maternal serum, and whether placental features consistent with maternal vascular malperfusion further affect their concentrations.

MATERIAL AND METHODS

This historical study included 154 women with singleton pregnancies complicated by PPROM between gestational ages 34+0 and 36+6 weeks. Transabdominal amniocentesis was performed as part of standard clinical management to evaluate the intra-amniotic environment. Women were categorized into two subgroups based on the presence of microorganisms and/or their nucleic acids in amniotic fluid (determined by culturing and molecular biology method) and intra-amniotic inflammation (by amniotic fluid interleukin-6 concentration evaluation): (1) those with the presence of microorganisms and/or inflammation (at least one present) and (2) those with negative amniotic fluid for infection/inflammation (absence of both). Concentrations of sFlt-1 and PlGF were assessed using the Elecsys® sFlt-1 and Elecsys® PlGF immunoassays and converted into multiples of medians.

RESULTS

Women with the presence of microorganisms and/or inflammation in amniotic fluid had lower serum concentrations of sFlt-1 and sFlt-1/PlGF ratios and higher concentrations of PlGF compared with those with negative amniotic fluid. (sFlt-1: presence: median 1.0 multiples of the median (MoM), vs negative: median: 1.5 MoM, P = 0.003; PlGF: presence: median 0.7 MoM, vs negative: median 0.4 MoM, P = 0.02; sFlt-1/PlGF: presence: median 8.9 vs negative 25.0, P = 0.001). Higher serum concentrations of sFlt-1 and sFlt-1/PlGF ratios as well as lower concentrations of PlGF were found in the subsets of women with maternal vascular malperfusion than in those without maternal vascular malperfusion.

CONCLUSIONS

Among women experiencing late PPROM, angiogenic imbalance in maternal serum is primarily observed in those without both microbial invasion of the amniotic cavity and intra-amniotic inflammation. Additionally, there is an association between angiogenic imbalance and the presence of maternal vascular malperfusion.

Maternal Exposure to Environmental Air Pollution and Premature Rupture of Membranes: Evidence from Southern China

BACKGROUND Exposure to air pollution (AP) during pregnancy is associated with pre-labor rupture of membranes (PROM). However, there is limited research on this topic, and the sensitive exposure windows remain unclear. The present study assessed the association between AP exposure and the risk of PROM, as well as seeking to identify the sensitive time windows. MATERIAL AND METHODS This retrospective study analyzed 4276 pregnant women's data from Tongling Maternal and Child Health Hospital from 2020 to 2022. We obtained air pollution data, including particulate matter (PM) with an aerodynamic diameter of ≤2.5 μm (PM₂․₅), particulate matter with an aerodynamic diameter of ≤10 μm (PM₁₀), nitrogen dioxide (NO₂), and ozone (O₃), from the Tongling Ecology and Environment Bureau. Demographic information was extracted from medical records. We employed a distributed lag model to identify the sensitive exposure windows of prenatal AP affecting the risk of PROM. We conducted a sensitivity analysis based on pre-pregnancy BMI. RESULTS We found a significant association between prenatal exposure to AP and increased PROM risk after adjusting for confounders, and the critical exposure windows of AP were the 6th to 7th months of pregnancy. In the underweight group, an increase of 10 µg/m³ in PM₂․₅ was associated with a risk of PROM, with an odds ratio (OR) of 1.48 (95% CI: 1.16, 1.89). Similarly, a 10 µg/m³ increase in PM₁₀ was associated with a risk of PROM, with an OR of 1.45 (95% CI: 1.05, 1.77). CONCLUSIONS Prenatal exposure to AP, particularly during months 6-7 of pregnancy, is associated with an increased risk of PROM. This study extends and strengthens the evidence on the association between prenatal exposure to AP and the risk of PROM, specifically identifying the critical exposure windows.

Effects of vitamin D in pregnancy on maternal and offspring health-related outcomes: An umbrella review of systematic review and meta-analyses

BACKGROUND

Vitamin D deficiency has been linked with several adverse maternal and fetal outcomes.

OBJECTIVE

To summarize systematic reviews and meta-analyses evaluating the effects of vitamin D deficiency and of vitamin D supplementation in pregnancy on maternal and offspring health-related outcomes.

METHODS

Prior to conducting this umbrella review, we registered the protocol in PROSPERO (CRD42022368003). We conducted searches in PubMed, Embase, and Cochrane Library for systematic reviews and meta-analyses on vitamin D in pregnancy, from database inception to October 2, 2023. All outcomes related to vitamin D in pregnancy obtained from the systematic reviews and meta-analyses were extracted.

DATA EXTRACTION

Two reviewers independently chose studies and collected information on health outcomes. The quality of the included articles' methodology was assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews-2).

RESULTS

We identified 16 eligible systematic reviews and meta-analyses, which included 250,569 women. Our results demonstrated that vitamin D deficiency in pregnancy is associated with increased risk of preterm birth, small-for gestational age/low birth weight infants, recurrent miscarriage, bacterial vaginosis and gestational diabetes mellitus. Vitamin D supplementation in pregnancy increases birth weight, and reduces the risk of maternal pre-eclampsia, miscarriage, and vitamin D deficiency, fetal or neonatal mortality, as well as attention-deficit hyperactivity disorder, and autism spectrum disorder in childhood. In women with gestational diabetes mellitus, vitamin D supplementation in pregnancy can reduce the risk of maternal hyperbilirubinemia, polyhydramnios, macrosomia, fetal distress, and neonatal hospitalization.

CONCLUSION

Due to the association with adverse maternal and offspring health outcomes, we recommend the vitamin D status in pregnancy should be monitored, particularly in women at high risk of vitamin D deficiency. It is suggested that pregnant women take a dose of >400 IU/day of vitamin D supplementation during pregnancy to prevent certain adverse outcomes.

Heterogeneity of mesenchymal cells in human amniotic membrane at term

There is increasing interest in understanding the tissue biology of human amniotic membrane (hAM) given its applications in medicine. One cellular component is mesenchymal cells, which can be extracted, cultured and differentiated "in vitro" into various cell types. These studies show that there is heterogeneity among mesenchymal cells. The aim of this work is to study the membrane in situ to determine whether this cellular heterogeneity exists. The hAMs were obtained from caesarean deliveries at term and analyzed by histological techniques. Types I-III mesenchymal cells and Hofbauer were distinguished by light microscopy. Histochemically, mesenchymal cell types showed successively increasing positivity to: PAS, vimentin, fibronectin, and Concanavalin-A; VGEF, TGF-β2, PDGF-C, FGF-2. By the semiquantitative point of view, the percentage of Type II cells was 60%, significantly higher than the other types. With transmission electron microscopy, an intermediate cell type between II-III was observed. Strong vesiculation of the rough endoplasmic reticulum (RER) with exocytosis was observed. In addition, an accumulation of a similar material to the extracellular matrix in the RER caused its dilation especially in type IIITEM cells. Some of this material acquired a globular structure. These structures were also found free in the extracellular matrix. In conclusion, the mesenchymal cells of the fibroblastic layer of the hAMs studied are heterogeneous, with some undifferentiated and others with a probably senescent fibroblastic phenotype with accumulation in their RER of fibronectin. These results may be of interest to extract mesenchymal cells from hAMs for use in regenerative medicine and to better understand the mechanisms of fetal membrane rupture.

Histologic Evidence of Epithelial-Mesenchymal Transition and Autophagy in Human Fetal Membranes

Preterm, prelabor rupture of the human fetal membranes (pPROM) is involved in 40% of spontaneous preterm births worldwide. Cellular-level disturbances and inflammation are effectors of membrane degradation, weakening, and rupture. Maternal risk factors induce oxidative stress (OS), senescence, and senescence-associated inflammation of the fetal membranes as reported mechanisms related to pPROM. Inflammation can also arise in fetal membrane cells (amnion/chorion) due to OS-induced autophagy and epithelial-mesenchymal transition (EMT). Autophagy, EMT, and their correlation in pPROM, along with OS-induced autophagy-related changes in amnion and chorion cells in vitro, were investigated. Immunocytochemistry staining of cytokeratin-18 (epithelial marker)/vimentin (mesenchymal marker) and proautophagy-inducing factor LC3B were performed in fetal membranes from pPROM, term not in labor, and term labor. Ultrastructural changes associated with autophagy were verified by transmission electron microscopy of the fetal membranes and in cells exposed to cigarette smoke extract (an OS inducer). EMT and LC3B staining was compared in the chorion from pPROM versus term not in labor. Transmission electron microscopy confirmed autophagosome formation in pPROM amnion and chorion. In cell culture, autophagosomes were formed in the amnion with OS treatment, while autophagosomes were accumulated in both cell types with autophagy inhibition. This study documents the association between pPROMs and amniochorion autophagy and EMT, and supports a role for OS in inducing dysfunctional cells that increase inflammation, predisposing membranes to rupture.

The relationship between maternal exposure to ambient air pollutants and premature rupture of membranes: A systematic review and meta-analysis

Air pollution is an environmental stimulus that may predispose pregnant women to preterm rapture of membrane (PROM). However, the relationship of maternal exposure to air pollutants and PROM is still unclear. To investigate the relationship between the long-term and short-term maternal exposure to air pollution and PROM. We searched all studies published in PubMed, Embase and Web of Science up to February 2024. The studies provided quantitative effect estimates with 95% confidence intervals, for the impact of short-term (<30 days) or long-term (≥30 days) maternal exposure to air pollutants on PROM, preterm PROM (PPROM) or term PROM (TPROM). The odds ratio (OR), risk ratio (RR), or hazard ratio (HR), with 95% confidence intervals was extracted, and RR or HR were deemed as OR because of the low prevalence of PROM. Fixed- or random-effects meta-analyses performed. In total, 17 relevant studies were included. Maternal exposure to PM2.5 in the second trimester increases the risk of PROM (pooled OR = 1.15, 95%CI: 1.05-1.26). Maternal exposure to PM10, NO2, NO, CO and SO2 during pregnancy and short-term maternal exposure to PM2.5, NO2, SO2 and O3 also associate with PROM occurrence. The results of the study show that both long-term maternal exposure in the second or third trimester and short-term maternal exposure to ambient air pollution can increase the risk of PROM.

Frontiers in the Etiology and Treatment of Preterm Premature Rupture of Membrane: From Molecular Mechanisms to Innovative Therapeutic Strategies

Preterm premature rupture of membranes (pPROM) poses a significant threat to fetal viability and increases the risk for newborn morbidities. The perinatal period of preterm infants affected by pPROM is often characterized by higher rates of mortality and morbidity, with associated risks of cerebral palsy, developmental delays, compromised immune function, respiratory diseases, and sensory impairments. pPROM is believed to result from a variety of causes, including but not limited to microbially induced infections, stretching of fetal membranes, oxidative stress, inflammatory responses, and age-related changes in the fetal-placental interface. Maternal stress, nutritional deficiencies, and medically induced procedures such as fetoscopy are also considered potential contributing factors to pPROM. This comprehensive review explores the potential etiologies leading to pPROM, delves into the intricate molecular mechanisms through which these etiologies cause membrane ruptures, and provides a concise overview of diagnostic and treatment approaches for pPROM. Based on available therapeutic options, this review proposes and explores the possibilities of utilizing a novel composite hydrogel composed of amniotic membrane particles for repairing ruptured fetal membranes, thereby holding promise for its clinical application.

YAP-mediated trophoblast dysfunction: the common pathway underlying pregnancy complications

Yes-associated protein (YAP) is a pivotal regulator in cellular proliferation, survival, differentiation, and migration, with significant roles in embryonic development, tissue repair, and tumorigenesis. At the maternal-fetal interface, emerging evidence underscores the importance of precisely regulated YAP activity in ensuring successful pregnancy initiation and progression. However, despite the established association between YAP dysregulation and adverse pregnancy outcomes, insights into the impact of aberrant YAP levels in fetal-derived, particularly trophoblast cells, and the ensuing dysfunction at the maternal-fetal interface remain limited. This review comprehensively examines YAP expression and its regulatory mechanisms in trophoblast cells throughout pregnancy. We emphasize its integral role in placental development and maternal-fetal interactions and delve into the correlations between YAP dysregulation and pregnancy complications. A nuanced understanding of YAP's functions during pregnancy could illuminate intricate molecular mechanisms and pave the way for innovative prevention and treatment strategies for pregnancy complications. Video Abstract.

Amniotic fluid CD36 in pregnancies complicated by spontaneous preterm delivery: a retrospective cohort study

OBJECTIVE

The aim of this study was to evaluate CD36 concentrations in amniotic fluid in pregnancies complicated by spontaneous delivery with intact fetal membranes (preterm labor, PTL) and preterm prelabor rupture of membranes (PPROM) with respect to the presence of the intra-amniotic infection.

METHODS

A total of 80 women with PPROM and 71 with PTL were included in the study. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid CD36 concentrations were assessed by enzyme-linked immunosorbent assay. Microbial colonization of the amniotic cavity (MIAC) was determined by the cultivation and non-cultivation approach. Intra-amniotic inflammation (IAI) was defined as an amniotic fluid bedside interleukin-6 concentration ≥3000 pg/mL. Intra-amniotic infection was characterized by the presence of both MIAC and IAI.

RESULTS

Women with PPROM with intra-amniotic infection had higher amniotic fluid CD36 concentrations than women without infection (with infection: median 346 pg/mL, IQR 262-384 vs. without infection: median 242 pg/mL, IQR 199-304; p = .006) A positive correlation between amniotic fluid CD36 concentrations and interleukin-6 concentrations was found (rho = 0.48; p < .0001). In PTL pregnancies, no statistically significant difference was found in the amniotic fluid level of CD36 between intra-amniotic infection, sterile IAI, and negative amniotic fluid.

CONCLUSIONS

The presence of intra-amniotic infection is characterized by higher amniotic fluid CD36 concentrations in pregnancies complicated by PPROM. An amniotic fluid CD36 cutoff value of 252.5 pg/mL was found to be optimal for the prediction of intra-amniotic infection. In PTL pregnancies, no statistically significant change in CD36 concentration was found with respect to the presence of intra-amniotic infection.

Residential greenspace counteracts PM2.5 on the risks of preterm birth subtypes: A multicenter study

BACKGROUND

The association between residential greenspace and preterm birth (PTB) risk remained inconclusive. The PTB subtypes have been ignored and the effect of co-exposure of PM2.5 on PTB risk is still unclear.

OBJECTIVE

To investigate the independent, interactive, and mixed effects of residential greenspace and PM2.5 on the risk of PTB subtypes.

METHODS

A total of 19,900 singleton births from 20 hospitals in Shanghai, China, from 2015 to 2017 were included. The Normalized Difference Vegetation Index (NDVI) within 500 m and 1000 m buffers of the maternal residence and a combined geoscience-statistical model-derived PM2.5 and its six components were used as the exposure measures. PTB (<37 completed weeks of gestation) were divided into early PTB (24-33 weeks) vs. late PTB (34-36 weeks) and into spontaneous PTB (sPTB), preterm premature rupture of the fetal membranes (PPROM), and iatrogenic PTB. Multivariable logistic regression models were applied to assess the independent and interactive effects of NDVI and PM2.5 on PTB in each trimester. The quantile g-computation approach was employed to explore the mixture effect of PM2.5 components and greenspace across the pregnancy and to determine the main contributors.

RESULTS

Levels of PM2.5 and greenspace were associated with increased [aOR (95%CI) ranging from 1.18 (1.07, 1.30) to 3.36 (2.45, 4.64)] and decreased risks [aORs (95%CI) ranging from 0.64 (0.53, 0.78) to 0.86 (0.73, 0.99)] of PTB subtypes, respectively. At the same PM2.5 level, higher residential greenspace was associated with lower risks, and vice versa. All these associations were more pronounced in late pregnancy. Early PTB and PPROM were the main affected subtypes, and the main drivers in PM2.5 were black carbon and ammonium.

CONCLUSIONS

Residential greenspace may mitigate the PTB risks due to PM2.5 exposure during pregnancy.

Impact of pre-pregnancy weight on the risk of premature rupture of membranes in Chinese women

Objective

The objective of this study was to investigate the influence of pre-pregnancy body mass index (BMI) on the incidence of premature rupture of membranes (PROM) among Chinese women.

Methods

This was a hospital-based retrospective cohort study of 75,760 Chinese women who had live singleton births between 2016 and 2020. In this study, we utilized logistic regression analysis to estimate the association between pre-pregnancy BMI and PROM based on gestational age.

Results

Prior to pregnancy, being overweight or obese was found to be significantly associated with an increased risk of preterm premature rupture of membranes (PPROM), as evidenced by adjusted odds ratios and 95 % confidence intervals of 1.336 (1.173-1.522) and 1.411 (1.064-1.872), respectively. Those with PPROM were divided into three groups according to gestational age: 22-27, 28-31, and 32-36 weeks. Women who were overweight or obese prior to pregnancy had a higher likelihood of experiencing PROM between 22 and 27 weeks of gestation. This finding remained consistent even after controlling for potential confounding factors, such as gestational diabetes mellitus (GDM), gestational hypertension, preeclampsia, hydramnios, cervical abnormalities, and a history of preterm birth.

Conclusion

Our research findings indicate that being overweight or obese before pregnancy is linked to a higher likelihood of experiencing PPROM. Therefore, achieving optimal weight before pregnancy is important to prevent PPROM and its associated complications.

Hydrogen sulfide inhibits the rupture of fetal membranes throngh anti-aging pathways

INTRODUCTION

To investigate the relationship between hydrogen sulfide(H2S) and the senescence level of the fetal membranes, and to elucidate how H2S affects the integrity of the fetal membranes.

METHODS

The H2S and the senescence levels of fetal membranes, and the expressions of H2S synthase CBS and CSE were detected in the preterm (PT) group and the preterm premature ruptured membranes (pPROM) group. The effects of H2S donors and knockdown of CBS on the senescence level of amniotic epithelial cells, and the expression level of matrix metalloproteinases (MMPs) and epithelial-mesenchymal translation (EMT) were observed.

RESULTS

The level of H2S in the fetal membranes in the pPROM group is significantly lower than that in the PT group matched for gestational age. The level of H2S is negatively correlated with the senescence level of fetal membranes. Treatment with H2S donors reduced cell senescence and MMPs expression, but did not affect EMT. CBS siRNA transfection accelerated the senescence of amniotic epithelial cells, and promoted the expression of MMPs and EMT occurrence, but l-cysteine could reverse these effects.

DISCUSSION

Our study suggests that H2S, through its anti-aging effect, can influence the expression of MMPs and EMT, thereby contributing to the maintenance of fetal membrane integrity.

Nuclear erythroid 2-related factor 2 protects against reactive oxygen species -induced preterm premature rupture of membranes through regulation of mitochondria†

Preterm premature rupture of membranes (pPROM) is a major cause of preterm birth and neonatal mortality. Reactive oxygen species (ROS) have been identified as a critical factor in the development of pPROM. Mitochondria are known to be the primary source of ROS and play a vital role in maintaining cellular function. The Nuclear erythroid 2-related factor 2 (NRF2) has been demonstrated to play a crucial role in regulating mitochondrial function. However, research exploring the impact of NRF2-regulated mitochondria on pPROM is limited. Therefore, we collected fetal membrane tissues from pPROM and spontaneous preterm labor (sPTL) puerpera, measured the expression level of NRF2, and evaluated the degree of mitochondrial damage in both groups. In addition, we isolated human amniotic epithelial cells (hAECs) from the fetal membranes and used small interfering RNA (siRNA) to suppress NRF2 expression, enabling us to evaluate the impact of NRF2 on mitochondrial damage and ROS production. Our findings indicated that the expression level of NRF2 in pPROM fetal membranes was significantly lower than in sPTL fetal membranes, accompanied by increased mitochondrial damage. Furthermore, after the inhibition of NRF2 in hAECs, the degree of mitochondrial damage was significantly exacerbated, along with a marked increase in both cellular and mitochondrial ROS levels. The regulation of the mitochondrial metabolic process via NRF2 in fetal membranes has the potential to influence ROS production.

IL-33/ST2 axis of human amnion fibroblasts participates in inflammatory reactions at parturition

BACKGROUND

Inflammation of the fetal membranes is an indispensable event of labor onset at both term and preterm birth. Interleukin-33 (IL-33) is known to participate in inflammation via ST2 (suppression of tumorigenicity 2) receptor as an inflammatory cytokine. However, it remains unknown whether IL-33/ST2 axis exists in human fetal membranes to promote inflammatory reactions in parturition.

METHODS

The presence of IL-33 and ST2 and their changes at parturition were examined with transcriptomic sequencing, quantitative real-time polymerase chain reaction, Western blotting or immunohistochemistry in human amnion obtained from term and preterm birth with or without labor. Cultured primary human amnion fibroblasts were utilized to investigate the regulation and the role of IL-33/ST2 axis in the inflammation reactions. A mouse model was used to further study the role of IL-33 in parturition.

RESULTS

Although IL-33 and ST2 expression were detected in both epithelial and fibroblast cells of human amnion, they are more abundant in amnion fibroblasts. Their abundance increased significantly in the amnion at both term and preterm birth with labor. Lipopolysaccharide, serum amyloid A1 and IL-1β, the inflammatory mediators pertinent to labor onset, could all induce IL-33 expression through NF-κB activation in human amnion fibroblasts. In turn, via ST2 receptor, IL-33 induced the production of IL-1β, IL-6 and PGE2 in human amnion fibroblasts via the MAPKs-NF-κB pathway. Moreover, IL-33 administration induced preterm birth in mice.

CONCLUSION

IL-33/ST2 axis is present in human amnion fibroblasts, which is activated in both term and preterm labor. Activation of this axis leads to increased production of inflammatory factors pertinent to parturition, and results in preterm birth. Targeting the IL-33/ST2 axis may have potential value in the treatment of preterm birth.

Paradoxical Induction of ALOX15/15B by Cortisol in Human Amnion Fibroblasts: Implications for Inflammatory Responses of the Fetal Membranes at Parturition

Inflammation of the fetal membranes is an indispensable event of parturition, with increasing prostaglandin E2 (PGE2) synthesis as one of the ultimate products that prime labor onset. In addition to PGE2, the fetal membranes also boast a large capacity for cortisol regeneration. It is intriguing how increased PGE2 synthesis is achieved in the presence of increasing amounts of classical anti-inflammatory glucocorticoids in the fetal membranes at parturition. 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) synthesized by lipoxygenase 15/15B (ALOX15/15B) has been shown to enhance inflammation-induced PGE2 synthesis in amnion fibroblasts. Here, we examined whether glucocorticoids could induce ALOX15/15B expression and 15(S)-HETE production to promote PGE2 synthesis in amnion fibroblasts at parturition. We found that cortisol and 15(S)-HETE abundance increased parallelly in the amnion at parturition. Cortisol induced ALOX15/15B expression and 15(S)-HETE production paradoxically in amnion fibroblasts. Mechanism study revealed that this paradoxical induction was mediated by p300-mediated histone acetylation and interaction of glucocorticoid receptor with transcription factors CREB and STAT3. Conclusively, cortisol regenerated in the fetal membranes can paradoxically induce ALOX15/15B expression and 15(S)-HETE production in human amnion fibroblasts, which may further assist in the induction of PGE2 synthesis in the inflammatory responses of the fetal membranes for parturition.

The change of inflammatory status and vaginal flora in pregnant women with premature rupture of membranes

Introduction. Premature rupture of the membrane (PROM) can trigger significant maternal complications, even maternal and fetal morbidity or mortality.Hypothesis. Inflammatory status and vaginal flora might be utilized to predict the occurrence of PROM.Aim. To explore the association between the occurrence of PROM and vaginal flora and inflammatory status alteration.Methodology. A case-control cross-sectional study was carried out on 140 pregnant women with or without PROM. Socio-demographic characteristics, vaginal flora assessment, pregnant outcomes and Apgar score information were retrieved.Results. Pregnant women with PROM showed an increased incidence of vulvovaginal candidiasis (VVC), trichomonas vaginitis (TV) and bacterial vaginitis (BV) with dysregulated vaginal flora and diminished fetal tolerance of labour indicated by down-regulated Apgar score. The increased rate of prematurity, puerperal infection and neonatal infection could be detected in PROM patients with imbalanced vaginal flora compared with PROM patients with normal vaginal flora. ROC analysis suggested IL-6 and TNF-α yielded the best discrimination for the prediction of PROM.Conclusion. Altered vaginal and inflammatory status are associated with PROM, and IL-6 and TNF-α can predict the occurrence of PROM.

Ureaplasma parvum infection induces inflammatory changes in vaginal epithelial cells independent of sialidase

BACKGROUND

Ureaplasma, a genus of the order Mycoplasmatales and commonly grouped with Mycoplasma as genital mycoplasma is one of the most common microbes isolated from women with infection/inflammation-associated preterm labor (PTL). Mycoplasma spp. produce sialidase that cleaves sialic acid from glycans of vaginal mucous membranes and facilitates adherence and invasion of the epithelium by pathobionts, and dysregulated immune response. However, whether Ureaplasma species can induce the production of sialidase is yet to be demonstrated. We examined U. parvum-infected vaginal epithelial cells (VECs) for the production of sialidase and pro-inflammatory cytokines.

METHODS

Immortalized VECs were cultured in appropriate media and treated with U. parvum in a concentration of 1 × 10⁵ DNA copies/ml. After 24 h of treatment, cells and media were harvested. To confirm infection and cell uptake, immunocytochemistry for multi-banded antigen (MBA) was performed. Pro-inflammatory cytokine production and protein analysis for sialidase confirmed pro-labor pathways.

RESULTS

Infection of VECs was confirmed by the presence of intracellular MBA. Western blot analysis showed no significant increase in sialidase expression from U. parvum-treated VECs compared to uninfected cells. However, U. parvum infection induced 2-3-fold increased production of GM-CSF (p = 0.03), IL-6 (p = 0.01), and IL-8 (p = 0.01) in VECs compared to controls.

CONCLUSION

U. parvum infection of VECs induced inflammatory imbalance associated with vaginal dysbiosis but did not alter sialidase expression at the cellular level. These data suggest that U. parvum's pathogenic effect could be propagated by locally produced pro-inflammatory cytokines and, unlike other genital mycoplasmas, may be independent of sialidase.

Is human labor at term an inflammatory condition?†

Parturition at term in normal pregnancy follows a predictable sequence of events. There is some evidence that a state of inflammation prevails in the reproductive tissues during labor at term, but it is uncertain whether this phenomenon is the initiating signal for parturition. The absence of a clear temporal sequence of inflammatory events prior to labor casts doubt on the concept that normal human labor at term is primarily the result of an inflammatory cascade. This review examines evidence linking parturition and inflammation in order to address whether inflammation is a cause of labor, a consequence of labor, or a separate but related phenomenon. Finally, we identify and suggest ways to reconcile inconsistencies regarding definitions of labor onset in published research, which may contribute to the variability in conclusions regarding the genesis and maintenance of parturition. A more thorough understanding of the processes underlying normal parturition at term may lead to novel insights regarding abnormal labor, including spontaneous preterm labor, preterm premature rupture of the fetal membranes, and dysfunctional labor, and the role of inflammation in each.

Inflammatory Molecules Responsible for Length Shortening and Preterm Birth

It is estimated that inflammation at the placental-maternal interface is directly responsible for or contributes to the development of 50% of all premature deliveries. Chorioamnionitis, also known as the premature rupture of the amniotic membrane in the mother, is the root cause of persistent inflammation that preterm newborns experience. Beyond contributing to the onset of early labor, inflammation is a critical element in advancing several conditions in neonates, including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity and periventricular leukomalacia. Notably, the immune systems of preterm infants are not fully developed; immune defense mechanisms and immunosuppression (tolerance) have a delicate balance that is easily upset in this patient category. As a result, premature infants are exposed to different antigens from elements such as hospital-specific microbes, artificial devices, medications, food antigens and hypoxia/hyperoxia. This has detrimental implications for preterm deliveries of less than 28 weeks because they have not yet evolved the mechanisms to tolerate maternal and self-antigens.

Acute and chronic maternal exposure to fine particulate matter and prelabor rupture of the fetal membranes: A nation-wide survey in China

BACKGROUND

Prelabor rupture of the fetal membranes (PROM) is a major contributor to adverse perinatal outcomes. Some epidemiologic studies explored the association between maternal PM_2.5 exposure and PROM but failed to treat the labor induction and prelabor cesarean section as censored observations.

OBJECTIVE

We aimed to evaluated whether acute and chronic maternal ambient PM_2.5 exposure may increase the risk of PROM in China.

METHODS

This study was based on the China Labor and Delivery Survey, a nationwide multicenter investigation. Included in the current analysis were 45,879 singleton spontaneous births in 96 hospitals in mainland China from 2015 to 2017. Outcomes were PROM, preterm PROM (<37 weeks' gestation) and term PROM (≥37 weeks' gestation). Daily concentration of PM_2.5 at 1 km spatial resolution was estimated by gap-filling model. Generalized linear mixed model and mixed effects Cox model were applied to assess the associations of acute (from 0 to 4 days before delivery) and chronic (average gestational and trimester-specific) ambient PM_2.5 exposure with outcomes, respectively.

RESULTS

Significant associations were found between acute PM_2.5 exposures (per interquartile range increase) and the risk of preterm PROM (OR = 1.11; 95 % CI: 1.03, 1.19 for PM_2.5 on delivery day; OR = 1.10; 95 % CI: 1.02, 1.18 for PM_2.5 1 day before delivery) but not for term PROM. An interquartile range increase in PM_2.5 during the second trimester was associated with elevated risks of PROM (HR = 1.14; 95 % CI: 1.07, 1.22), preterm PROM (HR = 1.22; 95 % CI: 1.02, 1.45) and term PROM (HR = 1.13; 95 % CI: 1.06, 1.22), respectively. Women who were less educated, obese, or gave birth in a cold season appeared to be more sensitive to ambient PM_2.5 exposure.

CONCLUSION

Our findings suggest that both acute and chronic maternal exposures to ambient PM_2.5 during pregnancy are risk factors for PROM.

Testing of drugs using human feto-maternal interface organ-on-chips provide insights into pharmacokinetics and efficacy

Objectives: To improve preclinical drug testing during pregnancy, we developed multiple microfluidic organ-on-chip (OOC) devices that represent the structure, functions, and responses of the two feto-maternal interfaces (FMis) in humans (fetal membrane [FMi-OOC] and placenta [PLA-OOC]). This study utilized feto-maternal interface OOCs to test the kinetics and efficacy of drugs during pregnancy. Study design: The FMi-OOC contained amnion epithelial, mesenchymal, chorion trophoblast, and decidual cells. The PLA-OOC contained cytotrophoblasts (BeWo), syncytiotrophoblasts (BeWo + forskolin), and human umbilical vein endothelial cell lines. Therapeutic concentrations of either pravastatin or rosuvastatin (200 ng mL^-1), a model drug for these experiments, were applied to either decidua (in FMi-OOC) and syncytiotrophoblasts (in PLA-OOC) chambers under normal and oxidative stress conditions (induced by cigarette smoke extract [CSE 1 : 25]) to evaluate maternal drug exposure during normal pregnancy or oxidative stress (OS) associated pathologies, respectively. We determined statin pharmacokinetics and metabolism (LC-MS/MS), drug-induced cytotoxicity (LDH assay), and efficacy to reduce OS-induced inflammation (multiplex cytokine assay). Results: Both OOCs mimicked two distinct human feto-maternal interfaces. The drugs tested permeated the maternal-fetal cell layers of the FMi-OOC and PLA-OOC within 4 hours and generated cell and time-specific statin metabolites from various cell types without causing any cytotoxicity. OS-induced pro-inflammatory cytokines were effectively reduced by statins by increasing anti-inflammatory cytokine response across the FMi-OOC and PLA-OOC. Conclusion: Two distinct feto-maternal interface OOCs were developed, tested, and validated for their utility to conduct preclinical trials during pregnancy. We demonstrated that the placenta and fetal membranes-decidual interface both are able to transport and metabolize drugs and that the safety and efficacy of a drug can be determined using the anatomical structures recreated on OOCs.

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

First trimester screening of serum advanced glycation end products levels of pregnant women who have risk factors for gestational diabetes and their obstetric outcomes: a preliminary case-control study

Advanced glycation end-products (AGE) are complex compounds formed by nonenzymatic glycosylation of proteins, nucleic acids, and lipids with glucose in the blood. We aimed to investigate whether there was a difference in first-trimester serum AGE levels of pregnant women with and without risk factors for gestational diabetes mellitus (GDM) and their obstetric outcomes. There were 44 women in study group who have risk factors for GDM and 44 as controls. Demographic features, serum AGE levels, adverse perinatal and neonatal outcomes were compared between groups. Five patients (11.4%) in the study group and one patient (2.3%) in the control group were diagnosed as GDM (p = .2). The serum AGE values were not statistically different between the study and control groups. There were no statistical differences between groups in terms of adverse perinatal and neonatal outcomes. However, in the group with adverse perinatal outcome (n = 25), AGE values were higher than the control group. The results of our preliminary study suggested that high-risk women for GDM did not have increased serum levels of AGE in the first trimester. Nevertheless, a high first-trimester serum AGE level was found to be associated with adverse perinatal outcomes. IMPACT STATEMENTWhat is already known on this subject? Advanced glycation end products (AGE) are markers that are associated with diabetes and its complications. For pregnant women, a high third trimester serum AGEs levels were found in women who had gestational diabetes.What do the results of this study add? The results of our study revealed that first trimester screening of serum AGE levels of women who had risk factors for gestational diabetes was not discriminate. Nevertheless, a high first trimester serum AGE levels was associated with adverse perinatal outcome.What are the implications of these findings for clinical practice and/or further research? Whether reducing exogenous sources of AGE (western-style diet, smoking) before pregnancy will be associated with better pregnancy outcomes should be investigated in future studies.

Epithelial to mesenchymal transition (EMT) of feto-maternal reproductive tissues generates inflammation: a detrimental factor for preterm birth

Human pregnancy is a delicate and complex process where multiorgan interactions between two independent systems, the mother, and her fetus, maintain pregnancy. Intercellular interactions that can define homeostasis at the various cellular level between the two systems allow uninterrupted fetal growth and development until delivery. Interactions are needed for tissue remodeling during pregnancy at both fetal and maternal tissue layers. One of the mechanisms that help tissue remodeling is via cellular transitions where epithelial cells undergo a cyclic transition from epithelial to mesenchymal (EMT) and back from mesenchymal to epithelial (MET). Two major pregnancy-associated tissue systems that use EMT, and MET are the fetal membrane (amniochorion) amnion epithelial layer and cervical epithelial cells and will be reviewed here. EMT is often associated with localized inflammation, and it is a well-balanced process to facilitate tissue remodeling. Cyclic transition processes are important because a terminal state or the static state of EMT can cause accumulation of proinflammatory mesenchymal cells in the matrix regions of these tissues and increase localized inflammation that can cause tissue damage. Interactions that determine homeostasis are often controlled by both endocrine and paracrine mediators. Pregnancy maintenance hormone progesterone and its receptors are critical for maintaining the balance between EMT and MET. Increased intrauterine oxidative stress at term can force a static (terminal) EMT and increase inflammation that are physiologic processes that destabilize homeostasis that maintain pregnancy to promote labor and delivery of the fetus. However, conditions that can produce an untimely increase in EMT and inflammation can be pathologic. These tissue damages are often associated with adverse pregnancy complications such as preterm prelabor rupture of the membranes (pPROM) and spontaneous preterm birth (PTB). Therefore, an understanding of the biomolecular processes that maintain cyclic EMT-MET is critical to reducing the risk of pPROM and PTB. Extracellular vesicles (exosomes of 40-160 nm) that can carry various cargo are involved in cellular transitions as paracrine mediators. Exosomes can carry a variety of biomolecules as cargo. Studies specifically using exosomes from cells undergone EMT can carry a pro-inflammatory cargo and in a paracrine fashion can modify the neighboring tissue environment to cause enhancement of uterine inflammation.

Serum amyloid A, a host-derived DAMP in pregnancy?

Serum amyloid A (SAA) is one of the acute phase proteins released primarily from the liver in response to infection, inflammation and trauma. Emerging evidence indicates that SAA may function as a host-derived damage-associated molecular pattern (DAMP) protein to sense danger signals in pregnancy. The plasma SAA levels in maternal circulation are significantly increased in normal parturition, particularly in postpartum, as well as in gestational disorders such as premature preterm rupture of membranes, pre-eclampsia, gestational diabetes, and recurrent spontaneous abortion. It is likely that SAA acts as a non-specific DAMP molecule in response to inflammation and trauma experienced under these conditions. Notably, SAA can also be synthesized locally in virtually all gestational tissues. Within these gestational tissues, under the induction by bacterial products, pro-inflammatory cytokines and stress hormone glucocorticoids, SAA may exert tissue-specific effects as a toll-like receptor 4 (TLR4)-sensed DAMP molecule. SAA may promote parturition through stimulation of inflammatory reactions via induction of pro-inflammatory cytokines, chemokines, adhesion molecules and prostaglandins in the uterus, fetal membranes and placenta. In the fetal membranes, SAA may also facilitate membrane rupture through induction of matrix metalloproteases (MMPs)- and autophagy-mediated collagen breakdown and attenuation of lysyl oxidase-mediated collagen cross-linking. SAA synthesized in extravillous trophoblasts may promote their invasiveness into the endometrium in placentation. Here, we summarized the current understanding of SAA in pregnancy with an aim to stimulate in-depth investigation of SAA in pregnancy, which may help better understand how inflammation is initiated in gestational tissues in both normal and abnormal pregnancies.

Fetal Lung-Derived Exosomes in Term Labor Amniotic Fluid Induce Amniotic Membrane Senescence

The mechanism of parturition is still unclear. Evidence has shown that delivery is associated with cellular senescence of the amniotic membrane. We isolated fetal lung-associated exosomes from the amniotic fluid from term labor (TL-exos) and verified that the exosomes can cause primary human amniotic epithelial cell (hAEC) senescence and apoptosis and can release higher levels of senescence-associated secretory phenotype (SASP)-related molecules and proinflammatory damage-associated molecular patterns (DAMPs) than exosomes isolated from the amniotic fluid from term not in labor (TNIL-exos). The human lung carcinoma cell lines (A549) can be used as an alternative to alveolar type 2 epithelial cells producing pulmonary surfactant. Therefore, we isolated A549 cell-derived exosomes (A549-exos) and found that they can trigger hAEC to undergo the same aging process. Finally, the animal experiments suggested that A549-exos induced vaginal bleeding and preterm labor in pregnant mice. Therefore, we conclude that exosomes derived from fetal lungs in term labor amniotic fluid induce amniotic membrane senescence, which may provide new insight into the mechanism of delivery.

Canada's Colonial Genocide of Indigenous Peoples: A Review of the Psychosocial and Neurobiological Processes Linking Trauma and Intergenerational Outcomes

The policies and actions that were enacted to colonize Indigenous Peoples in Canada have been described as constituting cultural genocide. When one considers the long-term consequences from the perspective of the social and environmental determinants of health framework, the impacts of such policies on the physical and mental health of Indigenous Peoples go well beyond cultural loss. This paper addresses the impacts of key historical and current Canadian federal policies in relation to the health and well-being of Indigenous Peoples. Far from constituting a mere lesson in history, the connections between colonialist policies and actions on present-day outcomes are evaluated in terms of transgenerational and intergenerational transmission processes, including psychosocial, developmental, environmental, and neurobiological mechanisms and trauma responses. In addition, while colonialist policies have created adverse living conditions for Indigenous Peoples, resilience and the perseverance of many aspects of culture may be maintained through intergenerational processes.