Directed biomechanical compressive forces enhance fusion efficiency in model placental trophoblast cultures.

The syncytiotrophoblast is a multinucleated structure that arises from fusion of mononucleated cytotrophoblasts, to sheath the placental villi and regulate transport across the maternal-fetal interface. Here, we ask whether the dynamic mechanical forces that must arise during villous development might influence fusion, and explore this question using in vitro choriocarcinoma trophoblast models. We demonstrate that mechanical stress patterns arise around sites of localized fusion in cell monolayers, in patterns that match computational predictions of villous morphogenesis. We then externally apply these mechanical stress patterns to cell monolayers and demonstrate that equibiaxial compressive stresses (but not uniaxial or equibiaxial tensile stresses) enhance expression of the syndecan-1 and loss of E-cadherin as markers of fusion. These findings suggest that the mechanical stresses that contribute towards sculpting the placental villi may also impact fusion in the developing tissue. We then extend this concept towards 3D cultures and demonstrate that fusion can be enhanced by applying low isometric compressive stresses to spheroid models, even in the absence of an inducing agent. These results indicate that mechanical stimulation is a potent activator of cellular fusion, suggesting novel avenues to improve experimental reproductive modelling, placental tissue engineering, and understanding disorders of pregnancy development.

Engineering placental trophoblast fusion: A potential role for biomechanics in syncytialization.

The process by which placental trophoblasts fuse to form the syncytiotrophoblast around the chorionic villi is not fully understood. Mechanical features of the in vivo and in vitro culture environments have recently emerged as having the potential to influence fusion efficiency, and considering these mechanical cues may ultimately allow predictive control of trophoblast syncytialization. Here, we review recent studies that suggest that biomechanical factors such as shear stress, tissue stiffness, and dimensionally-related stresses affect villous trophoblast fusion efficiency. We then discuss how these stimuli might arise in vivo and how they can be incorporated in cultures to study and enhance villous trophoblast fusion. We believe that this mechanical paradigm will provide novel insight into manipulating the syncytialization process to better engineer improved models, understand disease progression, and ultimately develop novel therapeutic strategies.

Oncostatin M and STAT3 Signaling Pathways Support Human Trophoblast Differentiation by Inhibiting Inflammatory Stress in Response to IFNγ and GM-CSF.

Interleukin-6 (IL-6) superfamily cytokines play critical roles during human pregnancy by promoting trophoblast differentiation, invasion, and endocrine function, and maintaining embryo immunotolerance and protection. In contrast, the unbalanced activity of pro-inflammatory factors such as interferon gamma (IFNγ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) at the maternal-fetal interface have detrimental effects on trophoblast function and differentiation. This study demonstrates how the IL-6 cytokine family member oncostatin M (OSM) and STAT3 activation regulate trophoblast fusion and endocrine function in response to pro-inflammatory stress induced by IFNγ and GM-CSF. Using human cytotrophoblast-like BeWo (CT/BW) cells, differentiated in villous syncytiotrophoblast (VST/BW) cells, we show that beta-human chorionic gonadotrophin (ßhCG) production and cell fusion process are affected in response to IFNγ or GM-CSF. However, those effects are abrogated with OSM by modulating the activation of IFNγ-STAT1 and GM-CSF-STAT5 signaling pathways. OSM stimulation enhances the expression of STAT3, the phosphorylation of STAT3 and SMAD2, and the induction of negative regulators of inflammation (e.g., IL-10 and TGFß1) and cytokine signaling (e.g., SOCS1 and SOCS3). Using STAT3-deficient VST/BW cells, we show that STAT3 expression is required for OSM to regulate the effects of IFNγ in ßhCG and E-cadherin expression. In contrast, OSM retains its modulatory effect on GM-CSF-STAT5 pathway activation even in STAT3-deficient VST/BW cells, suggesting that OSM uses STAT3-dependent and -independent mechanisms to modulate the activation of pro-inflammatory pathways IFNγ-STAT1 and GM-CSF-STAT5. Moreover, STAT3 deficiency in VST/BW cells leads to the production of both a large amount of ßhCG and an enhanced expression of activated STAT5 induced by GM-CSF, independently of OSM, suggesting a key role for STAT3 in ßhCG production and trophoblast differentiation through STAT5 modulation. In conclusion, our study describes for the first time the critical role played by OSM and STAT3 signaling pathways to preserve and regulate trophoblast biological functions during inflammatory stress.

The application of epiphenotyping approaches to DNA methylation array studies of the human placenta.

Background : Genome-wide DNA methylation (DNAme) profiling of the placenta with Illumina Infinium Methylation bead arrays is often used to explore the connections between in utero exposures, placental pathology, and fetal development. However, many technical and biological factors can lead to signals of DNAme variation between samples and between cohorts, and understanding and accounting for these factors is essential to ensure meaningful and replicable data analysis. Recently, "epiphenotyping" approaches have been developed whereby DNAme data can be used to impute information about phenotypic variables such as gestational age, sex, cell composition, and ancestry. These epiphenotypes offer avenues to compare phenotypic data across cohorts, and to understand how phenotypic variables relate to DNAme variability. However, the relationships between placental epiphenotyping variables and other technical and biological variables, and their application to downstream epigenome analyses, have not been well studied. Results : Using DNAme data from 204 placentas across three cohorts, we applied the PlaNET R package to estimate epiphenotypes gestational age, ancestry, and cell composition in these samples. PlaNET ancestry estimates were highly correlated with independent polymorphic ancestry informative markers, and epigenetic gestational age, on average, was estimated within 4 days of reported gestational age, underscoring the accuracy of these tools. Cell composition estimates varied both within and between cohorts, but reassuringly were robust to placental processing time. Interestingly, the ratio of cytotrophoblast to syncytiotrophoblast proportion decreased with increasing gestational age, and differed slightly by both maternal ethnicity (lower in white vs. non-white) and genetic ancestry (lower in higher probability European ancestry). The cohort of origin and cytotrophoblast proportion were the largest drivers of DNAme variation in this dataset, based on their associations with the first principal component. Conclusions : This work confirms that cohort, array (technical) batch, cell type proportion, self-reported ethnicity, genetic ancestry, and biological sex are important variables to consider in any analyses of Illumina DNAme data. Further, we demonstrate that estimating epiphenotype variables from the DNAme data itself, when possible, provides both an independent check of clinically-obtained data and can provide a robust approach to compare variables across different datasets.

The Placenta-A New Source of Bile Acids during Healthy Pregnancy? First Results of a Gene Expression Study in Humans and Mice.

Bile acids (BAs) are natural ligands for several receptors modulating cell activities. BAs are synthesized via the classic (neutral) and alternative (acidic) pathways. The classic pathway is initiated by CYP7A1/Cyp7a1, converting cholesterol to 7α-hydroxycholesterol, while the alternative pathway starts with hydroxylation of the cholesterol side chain, producing an oxysterol. In addition to originating from the liver, BAs are reported to be synthesized in the brain. We aimed at determining if the placenta potentially represents an extrahepatic source of BAs. Therefore, the mRNAs coding for selected enzymes involved in the hepatic BA synthesis machinery were screened in human term and CD1 mouse late gestation placentas from healthy pregnancies. Additionally, data from murine placenta and brain tissue were compared to determine whether the BA synthetic machinery is comparable in these organs. We found that CYP7A1, CYP46A1, and BAAT mRNAs are lacking in the human placenta, while corresponding homologs were detected in the murine placenta. Conversely, Cyp8b1 and Hsd17b1 mRNAs were undetected in the murine placenta, but these enzymes were found in the human placenta. CYP39A1/Cyp39a1 and cholesterol 25-hydroxylase (CH25H/Ch25h) mRNA expression were detected in the placentas of both species. When comparing murine placentas and brains, Cyp8b1 and Hsd17b1 mRNAs were only detected in the brain. We conclude that BA synthesis-related genes are placentally expressed in a species-specific manner. The potential placentally synthesized BAs could serve as endocrine and autocrine stimuli, which may play a role in fetoplacental growth and adaptation.

How to carry out participatory research that takes account of sex and gender issues: a scoping review of guidelines targeting health inequities.

OBJECTIVE: Conducting participatory research (PR) aimed at improving health implies considering inequitable power relations, including those related to sex/gender (S/G). This necessitates specific skills and methods and may be challenging especially since guidelines are scarce. Our objective was to perform a scoping review to provide a typology of existing guidelines for researchers on how to take account of S/G in the context of PR in public health, with a focus on occupational and environmental health. METHODS: All steps of the research were conducted with the collaboration of an advisory committee, following PR principles. Nineteen documents were retained from 513 references identified in nine scientific databases and grey literature between 2000 and 2020. Data on recommendations were extracted and coded qualitatively. Cluster analysis based on similarities in recommendations proposed in the documents identified four types: (1) empowerment-centered; (2) concrete action-centered; (3) macrosystem-centered; and (4) stakeholder-centered. SYNTHESIS: Many sources gave pointers on how to include S/G during data collection and analysis or during the dissemination of findings, but there was a dearth of suggestions for building partnerships with stakeholders and producing sustainable S/G sociopolitical transformations. Occupational health PR showed less similarities with other public health subfields including environmental health PR. Power relationships with workplace stakeholders generated specific obstacles related to S/G integration that require further attention. Intersectionality and reflexive practices emerged as overarching themes. CONCLUSION: This review provides helpful guidelines to researchers at different stages of planning PR, ranging from familiarizing themselves with S/G approaches to anticipating difficulties in their ongoing S/G-transformative PR.

RéSUMé: OBJECTIF: Les recherches participatives (RP) visant l'amélioration de la santé doivent tenir compte de rapports de pouvoir inéquitables, incluant ceux liés au sexe/genre (S/G). Cela peut s'avérer difficile vu les compétences requises et la rareté de recommandations. Notre objectif consistait à réaliser une revue de portée menant à une typologie des recommandations existantes pour les chercheurs.euses sur l'intégration du S/G en contexte de RP en santé publique, particulièrement en santé environnementale ou au travail. MéTHODOLOGIE: Un comité d'encadrement a participé à chaque étape de l'étude. Nous avons retenu 19 documents parmi 513 références identifiées dans neuf bases de données scientifiques et la littérature grise (2000­2020). L'extraction et le codage qualitatif des recommandations a mené à une analyse de clusters basée sur les similitudes identifiant quatre types centrés sur : 1) pouvoir d'agir; 2) actions concrètes; 3) macro-système; et 4) parties prenantes. SYNTHèSE: Plusieurs sources indiquaient comment intégrer le S/G pendant la collecte/analyse des données ou la diffusion des résultats. Peu de recommandations touchaient l'aspect S/G au niveau des partenariats avec des parties prenantes ou des transformations sociopolitiques durables. Les recommandations en santé au travail étaient moins similaires aux autres sous-domaines de santé publique. Les relations de pouvoir en milieu de travail engendrent des obstacles spécifiques liés à l'intégration du S/G et nécessitent une attention particulière. L'intersectionnalité et les pratiques réflexives sont apparues comme des thèmes primordiaux. CONCLUSION: Les recommandations repérées aideront des chercheurs.euses à différents stades de leur parcours d'intégration du S/G dans une RP en cours, allant de la familiarisation à l'anticipation de difficultés.

Transformative learning for a sustainable and healthy future through ecosystem approaches to health: insights from 15 years of co-designed ecohealth teaching and learning experiences.

This paper presents insights from the work of the Canadian Community of Practice in Ecosystem Approaches to Health (CoPEH-Canada) and 15 years (2008-2022) of land-based, transdisciplinary, learner-centred, transformative learning and training. We have oriented our learning approaches to Head, Hands, and Heart, which symbolise cognitive, psychomotor, and affective learning, respectively. Psychomotor and affective learning are necessary to grapple with and enact far-reaching structural changes (eg, decolonisation) needed to rekindle healthier, reciprocal relationships with nature and each other. We acknowledge that these approaches have been long understood by Indigenous colleagues and communities. We have developed a suite of teaching techniques and resources through an iterative and evolving pedagogy based on participatory approaches and operating reciprocal, research-pedagogical cycles; integrated different approaches and ways of knowing into our pedagogy; and built a networked Community of Practice for continued learning. Planetary health has become a dominant framing for health-ecosystem interactions. This Viewpoint underscores the depth of existing scholarship, collaboration, and pedagogical expertise in ecohealth teaching and learning that can inform planetary health education approaches.

Profiling placental DNA methylation associated with maternal SSRI treatment during pregnancy.

Selective serotonin reuptake inhibitors (SSRIs) for treatment of prenatal maternal depression have been associated with neonatal neurobehavioral disturbances, though the molecular mechanisms remain poorly understood.  In utero exposure to SSRIs may affect DNA methylation (DNAme) in the human placenta, an epigenetic mark that is established during development and is associated with gene expression. Chorionic villus samples from 64 human placentas were profiled with the Illumina MethylationEPIC BeadChip; clinical assessments of maternal mood and SSRI treatment records were collected at multiple time points during pregnancy. Case distribution was 20 SSRI-exposed cases and 44 SSRI non-exposed cases. Maternal depression was defined using a mean maternal Hamilton Depression score > 8 to indicate symptomatic depressed mood ("maternally-depressed"), and we further classified cases into SSRI-exposed, maternally-depressed (n = 14); SSRI-exposed, not maternally-depressed (n = 6); SSRI non-exposed, maternally-depressed (n = 20); and SSRI non-exposed, not maternally-depressed (n = 24). For replication, Illumina 450K DNAme profiles were obtained from 34 additional cases from an independent cohort (n = 17 SSRI-exposed, n = 17 SSRI non-exposed). No CpGs were differentially methylated at FDR < 0.05 comparing SSRI-exposed to non-exposed placentas, in a model adjusted for mean maternal Hamilton Depression score, or in a model restricted to maternally-depressed cases with and without SSRI exposure. However, at a relaxed threshold of FDR < 0.25, five CpGs were differentially methylated (|Δß| > 0.03) by SSRI exposure status. Four were covered by the replication cohort measured by the 450K array, but none replicated. No CpGs were differentially methylated (FDR < 0.25) comparing maternally depressed to not depressed cases. In sex-stratified analyses for SSRI-exposed versus non-exposed cases (females n = 31; males n = 33), three additional CpGs in females, but none in males, were differentially methylated at the relaxed FDR < 0.25 cut-off. We did not observe large-scale alterations of DNAme in placentas exposed to maternal SSRI treatment, as compared to placentas with no SSRI exposure. We also found no evidence for altered DNAme in maternal depression-exposed versus depression non-exposed placentas. This novel work in a prospectively-recruited cohort with clinician-ascertained SSRI exposure and mood assessments would benefit from future replication.

Engineered models for placental toxicology: Emerging approaches based on tissue decellularization.

Recent increases in prescriptions and illegal drug use as well as exposure to environmental contaminants during pregnancy have highlighted the critical importance of placental toxicology in understanding and identifying risks to both mother and fetus. Although advantageous for basic science, current in vitro models often fail to capture the complexity of placental response, likely due to their inability to recreate and monitor aspects of the microenvironment including physical properties, mechanical forces and stiffness, protein composition, cell-cell interactions, soluble and physicochemical factors, and other exogenous cues. Tissue engineering holds great promise in addressing these challenges and provides an avenue to better understand basic biology, effects of toxic compounds and potential therapeutics. The key to success lies in effectively recreating the microenvironment. One strategy to do this would be to recreate individual components and then combine them. However, this becomes challenging due to variables present according to conditions such as tissue location, age, health status and lifestyle. The extracellular matrix (ECM) is known to influence cellular fate by working as a storage of factors. Decellularized ECM (dECM) is a recent tool that allows usage of the original ECM in a refurbished form, providing a relatively reliable representation of the microenvironment. This review focuses on using dECM in modified forms such as whole organs, scaffold sheets, electrospun nanofibers, hydrogels, 3D printing, and combinations as building blocks to recreate aspects of the microenvironment to address general tissue engineering and toxicology challenges, thus illustrating their potential as tools for future placental toxicology studies.

Integration of sex and gender in interventions by students in ergonomics.

This article aims to analyse the integration of sex and gender (s/g) by ergonomics students during their internship at the master's degree level, following training sessions on s/g issues in the workplace. This exploratory research used a descriptive mixed-methods design, encompassing evaluation of students' intention to use the content from the training (n = 13 students), and a multiple case study (n = 5 ergonomics interventions). The results show that while students found the training relevant, they only minimally integrated s/g in their interventions and when they did, it was primarily from an anthropometric and physiological perspective. In addition to discussing the training format limitations, the article discusses barriers to this integration: combining learning about s/g issues with learning about activity analysis is challenging; employers' and workers' organisations may be reluctant to approach s/g issues; and it is difficult for an ergonomist to integrate these issues when the employer's request does not specify it.Practitioner summary: This article aims to analyse the integration of s/g by ergonomics students during their internships. Findings show that they only minimally considered s/g. The discussion examines s/g training, organisational obstacles to inclusion of s/g during interventions, and how ergonomists can consider s/g in their practice.

The implications of the purinergic signaling throughout pregnancy.

Purinergic signaling is a necessary mechanism to trigger or even amplify cell communication. Its ligands, notably adenosine triphosphate (ATP) and adenosine, modulate specific membrane-bound receptors in virtually all human cells. Regardless of the stage of the pregnancy, cellular communication between maternal, placental, and fetal cells is the paramount mechanism to sustain its optimal status. In this review, we describe the crucial role of purinergic signaling on the regulation of the maternal-fetal trophic exchanges, immune control, and endocrine exchanges throughout pregnancy. The nature of the modulation of both ATP and adenosine on the embryo-maternal interface, going through placental invasion until birth delivery depends on the general maternal-fetal health state and consequently on the selective activation of their specific receptors. In addition, an increasing number of studies have been demonstrating the pivotal role of ATP and adenosine in modulating deleterious effects of suboptimal conditions of pregnancy. Here, we discuss the role of purinergic signaling on the balance that coordinates the embryo-maternal exchanges and a promising therapeutic venue in the context of pregnancy disorders.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus.

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Intrauterine Administration of Activated Peripheral Blood Mononuclear Cells in Intrauterine Insemination: A Prospective Double-Blind Randomized Clinical Trial.

OBJECTIVE: To evaluate the effect of intrauterine administration of activated peripheral blood mononuclear cells (PBMC) on intrauterine insemination (IUI) success rates. METHODS: This prospective double-blind randomized parallel clinical trial included 213 patients undergoing IUI at the Fertilys clinic. PBMC were isolated on the day of ovulation (day 0; D0) and stimulated with phytohemagglutinin (PHA) and human chorionic gonadotropin (hCG) for 48 hours (day 2; D2). Patients in the PBMC group (n = 108) underwent in utero administration of 1.106 cells on D2, while patients in the control group (n = 105) were administered sperm-washing medium. Distribution of CD4 T lymphocyte populations (n = 61) was assessed on D0 and D2. Pregnancy and live birth rates were also evaluated. RESULTS: Demographic and clinical characteristics, pregnancy rates, and live birth rates were not significantly different between the PBMC and control groups. Significantly higher levels of T helper (Th) 2, Th22, and T regulatory cells (P < 0.0001) and lower levels of Th17 cells were observed in hCG-activated PBMC at D2 than at D0. CONCLUSION: Intrauterine administration of PBMC was not beneficial in IUI patients. New clinical approaches to better identify patients requiring endometrium immunomodulation needs to be addressed.

Disease-specific extracellular matrix composition regulates placental trophoblast fusion efficiency.

The placental syncytiotrophoblast is a multinucleated layer that regulates transport between the mother and fetus. Fusion of trophoblasts is essential to form this layer, but this process can be disrupted in pregnancy-related disorders such as preeclampsia. Disease progression is also associated with changes in the extracellular matrix (ECM), but whether disease-specific ECM compositions play any causal role in establishing syncytiotrophoblast disease phenotypes remains unknown. Here, we develop a decellularization-based platform to isolate and characterize the role of human placental ECM composition on cell function, while controlling for the confounding effects of matrix structure and mechanics that can arise in conventional tissue decellularization/recellularization experiments. Using this approach, we demonstrate that ECM compositional changes that occur in preeclampsia have a statistically significant effect on adhesion, spreading, and fusion of placental trophoblasts. Proteomic analysis of ECM content then allowed us to identify and recreate selected differences in matrix composition; indicating that replacement of normally present Type IV Collagen by Type I Collagen in preeclampsia significantly affects fusion efficiency. These results indicate that disease-specific matrix compositions can play an important role in trophoblast fusion, suggesting novel matrix-targeting therapeutic strategies for pregnancy-related disorders. More broadly, this work demonstrates the utility of a decellularization-based approach in understanding the functional contributions of matrix composition in driving cellular disease phenotypes.

Febrile seizure incidence and age at first occurrence are associated with changes in placental normalized gene expression: the '3D' pregnancy cohort study.

Self-reported maternal prenatal stress (MPS) has been associated with earlier febrile seizure (FS) age of onset in offspring. Studies are needed to understand how the biological systems associated with exposure to psychological MPS are linked to seizure disorders in children. The present study aimed to investigate whether placental markers of MPS are linked to FS incidence and age at first occurrence. A subsample of children with FS (n = 28) and matched controls (n = 84), were drawn from the longitudinal 3D pregnancy cohort (N = 2366 mother-child dyads). Expression of placental genes associated with glucocorticoids, serotonin and fetal/placental growth were analysed from placental tissues, compared between groups and associated with age at first FS. Overall placental normalized gene expression was statistically different (p < .001). Children with FS showed overexpression of the serotonin transporter (mean difference = 0.61, 95% confidence interval [CI] = 0.9-1.13), connexin 43 (mean difference = 0.69, 95% CI = 0.30-1.09), zonula occludens-1 (mean difference = 0.84, 95% CI = 0.42-1.26) and underexpression of glucocorticoid receptor ß (mean difference = 0.84, 95% CI = -1.49 to 0.19) and serotonin receptor 2B (mean difference = 1.57, 95% CI = -2.35 to 0.78) compared to controls. Increased expression of the serotonin transporter predicted 37.2% in variation of age at first FS. The correlation matrix showed pregnancy-specific anxiety during the second trimester was moderately associated with age at first FS (r = -0.38) but was not a significant predictor in the regression model. Although our current results do not display a significant effect of self-reported MPS on FS, the present study is the first to show that placental gene biomarkers usually known to be associated with MPS display different expressions in children with FS. Specifically, our results suggest that placental genes associated with the glucocorticoid, serotonergic and fetal/placental growth systems may be candidate mechanisms leading to increased vulnerability offspring in FS. Because self-reported MPS was not found as a significant predictor in our statistical models, future studies are needed to investigate the mechanisms causing the observed changes in placental genes and their association with seizure disorders.

Relationships between Objectively Measured Sedentary Behavior during Pregnancy and Infant Birthweight.

BACKGROUND: Although numerous studies have assessed physical activity during pregnancy and relationships with infant outcomes, such as birthweight, few have evaluated sedentary behavior. Our objective was to evaluate sedentary behavior across pregnancy and relationships with infant birthweight in a sociodemographically diverse sample. METHODS: We measured device-assessed sedentary behavior and physical activity over three days at 16-18, 24-26, and 32-34 weeks gestation and infant birthweight from medical records among 71 participants. We used linear regression to assess relationships between sedentary behavior at each evaluation period with birthweight-for-gestational age Z-scores (BW-for-GA). RESULTS: There were no linear relationships between sedentary behavior and BW-for-GA at any evaluation period. We observed a modest curvilinear relationship between sedentary behavior at 16-18 weeks and BW-for-GA (R2 = 0.073, p = 0.021). Low and high levels of sedentary behavior predicted lower BW-for-GA. Multivariate models suggested that this relationship was independent of physical activity levels. CONCLUSIONS: Considering the high levels of sedentary behavior during pregnancy observed in many studies, even modest associations with birthweight merit further consideration. Relationships might not be evident later in pregnancy or if only linear relationships are considered. More detailed studies could help guide recommendations on sedentary behavior during pregnancy and the development of more comprehensive interventions.

Prenatal inflammation as a link between placental expression signature of tryptophan metabolism and preterm birth.

Spontaneous preterm birth is a serious medical condition responsible for substantial perinatal morbidity and mortality. Its phenotypic characteristics, preterm labor with intact membranes (PTL) and preterm premature rupture of the membranes (PPROM), are associated with significantly increased risks of neurological and behavioral alterations in childhood and later life. Recognizing the inflammatory milieu associated with PTL and PPROM, here, we examined expression signatures of placental tryptophan metabolism, an important pathway in prenatal brain development and immunotolerance. The study was performed in a well-characterized clinical cohort of healthy term pregnancies (n = 39) and 167 preterm deliveries (PTL, n = 38 and PPROM, n = 129). Within the preterm group, we then investigated potential mechanistic links between differential placental tryptophan pathway expression, preterm birth and both intra-amniotic markers (such as amniotic fluid interleukin-6) and maternal inflammatory markers (such as maternal serum C-reactive protein and white blood cell count). We show that preterm birth is associated with significant changes in placental tryptophan metabolism. Multifactorial analysis revealed similarities in expression patterns associated with multiple phenotypes of preterm delivery. Subsequent correlation computations and mediation analyses identified links between intra-amniotic and maternal inflammatory markers and placental serotonin and kynurenine pathways of tryptophan catabolism. Collectively, the findings suggest that a hostile inflammatory environment associated with preterm delivery underlies the mechanisms affecting placental endocrine/transport functions and may contribute to disruption of developmental programming of the fetal brain.

Variations in Relationships Between Perceived Stress and Birth Outcomes by Immigration Status.

INTRODUCTION: Past research shows that stress during pregnancy predicts adverse birth outcomes. These patterns might differ based on immigration status. Our objective was to analyze differences in relationships between perceived stress during pregnancy and birth outcomes by immigration status. METHODS: We recruited 81 pregnant women in Canada for a prospective longitudinal study of stress during pregnancy and infant development. Participants completed the Perceived Stress Questionnaire at 16-18, 24-26 and 32-34 weeks of pregnancy. Birth records were available for 73 women, including 24 non-immigrants, 18 long-term immigrants (≥ 5 years), and 31 recent immigrants (< 5 years). We used General Linear Models to test relationships between perceived stress and birthweight, birthweight for gestational age Z-scores, and gestational age, and differences based on immigration status. RESULTS: Controlling for sociodemographic covariates, we observed interactive relationships between immigration status and perceived stress with birthweight at 16-18 (p = 0.032, partial η2 = 0.11) and 24-26 weeks pregnancy (p = 0.012, partial η2 = 0.15). Results were similar for birthweight for gestational age Z-scores at 16-18 weeks (p = 0.016, partial η2 = 0.13) and 24-26 weeks pregnancy (p = 0.013, partial η2 = 0.14). Perceived stress predicted smaller birthweight measurements among long-term immigrants. No relation was found between perceived stress, immigration status and gestational age. DISCUSSION: Risk of adverse health outcomes, including birth outcomes, tends to increase with duration of residence among immigrants. Stress during pregnancy might represent one risk factor for adverse birth outcomes among long-term immigrant women. Promoting psychosocial health screening and care among immigrant women, and assuring continued care with acculturation, might improve both maternal and infant health outcomes.

Mechanobiological regulation of placental trophoblast fusion and function through extracellular matrix rigidity.

The syncytiotrophoblast is a multinucleated layer that plays a critical role in regulating functions of the human placenta during pregnancy. Maintaining the syncytiotrophoblast layer relies on ongoing fusion of mononuclear cytotrophoblasts throughout pregnancy, and errors in this fusion process are associated with complications such as preeclampsia. While biochemical factors are known to drive fusion, the role of disease-specific extracellular biophysical cues remains undefined. Since substrate mechanics play a crucial role in several diseases, and preeclampsia is associated with placental stiffening, we hypothesize that trophoblast fusion is mechanically regulated by substrate stiffness. We developed stiffness-tunable polyacrylamide substrate formulations that match the linear elasticity of placental tissue in normal and disease conditions, and evaluated trophoblast morphology, fusion, and function on these surfaces. Our results demonstrate that morphology, fusion, and hormone release is mechanically-regulated via myosin-II; optimal on substrates that match healthy placental tissue stiffness; and dysregulated on disease-like and supraphysiologically-stiff substrates. We further demonstrate that stiff regions in heterogeneous substrates provide dominant physical cues that inhibit fusion, suggesting that even focal tissue stiffening limits widespread trophoblast fusion and tissue function. These results confirm that mechanical microenvironmental cues influence fusion in the placenta, provide critical information needed to engineer better in vitro models for placental disease, and may ultimately be used to develop novel mechanically-mediated therapeutic strategies to resolve fusion-related disorders during pregnancy.