Alarmins at the maternal-fetal interface: involvement of inflammation in placental dysfunction and pregnancy complications 1

Nicotinamide improves the impaired extravillous trophoblast cell invasion induced by PM2.5 exposure-associated increase of TNFα secretion through the ROS/NF-κB/FLT1 pathway

It has been well acknowledged that maternal exposure to fine particulate matters (PM2.5) might lead to poor pregnancy outcomes including the intrauterine growth restriction (IUGR) by interfering with the placental development. Our previous studies have demonstrated that maternal PM2.5 exposure induces IUGR, accompanied with increased maternal circulating TNFα level and impaired extravillous trophoblast cells (EVTs) invasion in mice. In this study, HTR8/SVneo cells, the immortalized human EVTs line, were used to assess effects and the underlying molecular mechanisms of nicotinamide on the impaired EVTs invasion. Our results showed that, the placental FLT1 protein level was significantly increased whereas maternal serum nicotinamide concentration was remarkably decreased in PM2.5-exposured pregnant mice at GD17.5 (vaginal plug day=GD0.5), compared to that in normal GD17.5 pregnant mice. FLT1 expression in HTR8/SVneo cells was significantly up-regulated by TNFα treatment, and the down-regulated FLT1 expression effectively abated the inhibitory effects of TNFα on HTR8/SVneo cells migration and invasion. Meanwhile, TNFα promoted reactive oxygen species (ROS) production and NF-κB signaling pathway activation in HTR8/SVneo cells in a dose-dependent manner. Nicotinamide treatment significantly reversed the effects of TNFα on cell migration and invasion, as well as the FLT1 expression, ROS production and NF-κB pathway activation. In summary, increased TNFα induced by PM2.5 exposure inhibits EVTs invasion by activating the ROS/NF-κB/FLT1 signaling pathway, and this adverse effect could be attenuated by nicotinamide treatment, suggesting a potential application in the clinical intervention of PM2.5-induced IUGR.

The causal effect of exposure to air pollution on risk of adverse pregnancy outcomes: A two-sample Mendelian randomisation study

BACKGROUND

Epidemiological studies have examined the relation between air pollution (NOx, NO2, PM2.5, PM2.5-10, and PM10) and adverse pregnancy outcomes (APOs). There's increasing evidence that air pollution increases the risk of APOs. However, the results of these studies are controversial, and the causal relation remains uncertain. We aimed to assess whether a genetic causal link exists between air pollution and APOs and the potential effects of this relation.

METHODS

A novel two-sample Mendelian randomisation (MR) study used pooled data from a large-scale complete genome correlation study. The primary analysis method was inverse variance weighting (IVW), which explored the expose-outcome relationship for assessing single nucleotide polymorphisms (SNPs) associated with air pollution. Further sensitivity analysis, including MR-PRESSO, MR-Egger regression, and leave-one analysis, was used to test the consistency of the results.

RESULTS

There was a significant correlation between air pollution-related SNPs and APOs. A robust causal link was found between genetic susceptibility to air pollution and APOs.

CONCLUSIONS

Our MR analysis reveals a genetic causal relation between air pollution and APOs, which may help provide new insights into further mechanisms and clinical studies in air pollution-mediated APOs.

Stretch Causes cffDNA and HMGB1-Mediated Inflammation and Cellular Stress in Human Fetal Membranes

Danger-associated molecular patterns (DAMPs) are elevated within the amniotic cavity, and their increases correlate with advancing gestational age, chorioamnionitis, and labor. Although the specific triggers for their release in utero remain unclear, it is thought that they may contribute to the initiation of parturition by influencing cellular stress mechanisms that make the fetal membranes (FMs) more susceptible to rupture. DAMPs induce inflammation in many different tissue types. Indeed, they precipitate the subsequent release of several proinflammatory cytokines that are known to be key for the weakening of FMs. Previously, we have shown that in vitro stretch of human amnion epithelial cells (hAECs) induces a cellular stress response that increases high-mobility group box-1 (HMGB1) secretion. We have also shown that cell-free fetal DNA (cffDNA) induces a cytokine response in FM explants that is fetal sex-specific. Therefore, the aim of this work was to further investigate the link between stretch and the DAMPs HMGB1 and cffDNA in the FM. These data show that stretch increases the level of cffDNA released from hAECs. It also confirms the importance of the sex of the fetus by demonstrating that female cffDNA induced more cellular stress than male fetuses. Our data treating hAECs and human amnion mesenchymal cells with HMGB1 show that it has a differential effect on the ability of the cells of the amnion to upregulate the proinflammatory cytokines and propagate a proinflammatory signal through the FM that may weaken it. Finally, our data show that sulforaphane (SFN), a potent activator of Nrf2, is able to mitigate the proinflammatory effects of stretch by decreasing the levels of HMGB1 release and ROS generation after stretch and modulating the increase of key cytokines after cell stress. HMGB1 and cffDNA are two of the few DAMPs that are known to induce cytokine release and matrix metalloproteinase (MMP) activation in the FMs; thus, these data support the general thesis that they can function as potential central players in the normal mechanisms of FM weakening during the normal distension of this tissue at the end of a normal pregnancy.

Changes in serum inflammatory factors in group B streptococcal infection and their predictive value for premature rupture of membranes complicated by chorioamnionitis

Objective: The aim of this study as to unveil changes in serum inflammatory factors in pregnant women with genital tract group B Streptococcus (GBS) infection and their predictive value for premature rupture of membranes (PROM) complicated by chorioamnionitis (CS) and adverse pregnancy outcomes. Methods: The value of serum inflammatory factor levels in predicting PROM complicating CS and adverse pregnancy outcomes in GBS-infected pregnant women was evaluated by ELISA. Results: Serum IL-6, TNF-α, PCT and hs-CRP levels were higher in pregnant women with GBS infection. The combined diagnosis of these factors had excellent diagnostic value in PROM complicating CS and adverse pregnancy outcomes. Conclusion: Joint prediction of IL-6, TNF-α, PCT and hs-CRP has the best predictive value for PROM complicating CS and adverse pregnancy outcomes.

Implication of viruses in the etiology of preeclampsia

Preeclampsia is one of the most common disorders that poses threat to both mothers and neonates and a major contributor to perinatal morbidity and mortality worldwide. Viral infection during pregnancy is not typically considered to cause preeclampsia; however, syndromic nature of preeclampsia etiology and the immunomodulatory effects of viral infections suggest that microbes could trigger a subset of preeclampsia. Notably, SARS-CoV-2 infection is associated with an increased risk of preeclampsia. Herein, we review the potential role of viral infections in this great obstetrical syndrome. According to in vitro and in vivo experimental studies, viral infections can cause preeclampsia by introducing poor placentation, syncytiotrophoblast stress, and/or maternal systemic inflammation, which are all known to play a critical role in the development of preeclampsia. Moreover, clinical and experimental investigations have suggested a link between several viruses and the onset of preeclampsia via multiple pathways. However, the results of experimental and clinical research are not always consistent. Therefore, future studies should investigate the causal link between viral infections and preeclampsia to elucidate the mechanism behind this relationship and the etiology of preeclampsia itself.

Circulating levels of cytokines (IL-6, IL-10 and TGF- β) and CD4+CD25+FOXP3+Treg cell population in recurrent pregnancy loss

Recurrent pregnancy loss (RPL), a serious reproductive health issue, characterized by two or more pregnancy losses before 20th week of gestation. Globally, it affects 2-5% couples and the basis of the crisis is still unknown in 50% cases. Successful pregnancy is associated with pro and anti-inflammatory gestational phases that tolerate the semi-allogenic foetus, and disturbance leads to pregnancy complications like RPL. This case-control study aimed to assess the inflammatory status in the mid-gestation of ongoing pregnancy of women with (RPL) and without (NRPL) the history of RPL. Blood samples were processed for PBMC isolation, subjected to Flow-cytometry for CD4+CD25+FOXP3+Treg-cell population count and serum samples for IL-6, TGF-β, IL-10 cytokine levels (ELISA). Significant reduction in the percentage of Treg cells, and elevated values for IL-6/TGF-β and IL-6/IL-10 ratios were observed in RPL over NRPL group (p = 0.0001). Opposing results were seen with respect to the magnitude of history of RPL (2 vs. >2 losses). ROC curve analysis showed the superior discriminatory ability of cytokine ratios (IL-6/TGF-β > IL-6/IL-10) for RPL over Treg cells. Our findings are suggestive of pro-inflammatory dominance in mid-gestation of pregnant women with a history of RPL in general and greater than normal anti-inflammatory milieu in cases with > 2 pregnancy loss. As both sterile and infection related inflammation plays a role in pregnancy loss, studies enrolling women with favourable and unfavourable ongoing pregnancies may shed light on the importance of the present study for developing better management/therapeutic strategies.

Molecular examination for Coxiella burnetii and Brucella spp. infections in Iranian women experiencing spontaneous miscarriage

BACKGROUND

Spontaneous miscarriage, a leading health concern globally, often occurs due to various factors, including infections. Among these, Coxiella burnetii and Brucella spp. may have adverse effects on pregnancy outcomes. While previous research has established a link between infections and spontaneous miscarriage, our study aimed specifically to investigate the presence of these two pathogens in abortion samples from women who experienced spontaneous miscarriages in Iran. Our study can add to the existing knowledge by focusing on Iran, a region with a high prevalence of C. burnetii and Brucella spp. As a result, it could provide a better understanding and unique insights into the relationship of these pathogens with spontaneous miscarriages in endemic regions.

METHODS

From March 2021 to March 2022, a total of 728 abortion samples (including placenta and cotyledon) were collected from 409 women who had experienced spontaneous miscarriages in the provinces of Tehran, Fars, and West Azerbaijan in Iran. The specimens included 467 Formalin-Fixed Paraffin-Embedded (FFPE) and 261 fresh frozen samples. After DNA extraction from abortion samples, the quantitative real-time PCR (qPCR) assay targeted a specific fragment of the IS1111 and IS711 elements for molecular identification of C. burnetii and Brucella spp., respectively. Furthermore, the qPCR assay employing specific primers for different species was used to determine the species of Brucella.

RESULTS

Among the studied women, 1 out of 409 (0.24%) samples tested positive for Brucella spp., specifically Brucella melitensis. There were no positive specimens for C. burnetii.

CONCLUSIONS

Our study contributes to understanding the potential involvement of Brucella species in spontaneous infectious abortion within endemic regions. The identification of B. melitensis in this study highlights the need for further research in this area. However, while our results suggest a relatively low or zero identification of these pathogens in our sample population, this does not rule out the possibility of undetected infections. Therefore, it is critical to acknowledge the limitations of the molecular techniques used (qPCR), which may have potential limitations such as sensitivity and specificity. Moreover, because 64.15% of our samples were FFPE, the sensitivity of the qPCR test may be reduced. These raise concerns about the accuracy of the reported prevalence rates and the potential for false positives or negatives.

High mobility group box 1 in women with unexplained recurrent pregnancy loss

OBJECTIVES

To investigate whether high mobility group box 1 (HMGB1) is involved in unexplained recurrent pregnancy loss (uRPL).

METHODS

Plasma levels of HMGB1 were measured by ELISA in non-pregnant women with (n=44) and without (n=53 controls) uRPL. Their platelets and plasma-derived microvesicles (MVs) were also assayed for HMGB1. Endometrial biopsies were taken in selected uRPL (n=5) and control women (n=5) and the tissue expression of HMGB1 was determined by western blot and immunohistochemistry (IHC).

RESULTS

plasma levels of HMGB1 were significantly higher in women with uRPL than in control women. HMGB1 content in platelets and MVs obtained from women with uRPL was significantly higher than that obtained from control women. HMGB1 expression in endometrium was higher in tissues obtained from women with uRPL than in tissues obtained from control women. IHC analysis revealed that HMGB1 is expressed in endometrium with different patterns between uRPL and control women.

CONCLUSIONS

HMGB1 could be involved in uRPL.

The mediation of the placenta on the association between maternal ambient temperature exposure and birth weight

Studies have indicated that exposure to low and high temperatures during pregnancy negatively affects fetal development. The placenta plays vital functions in fetal development and could also be impacted by suboptimal temperatures. However, whether the placenta mediates the association between suboptimal temperature and birth weight is unknown. Our study aims to evaluate the association between ambient temperature and birth weight as well as the mediation effect of the placenta. A prospective birth cohort study was conducted during 2017-2020 in Guangzhou, China (n = 3349 participants). We defined extreme temperature exposure during the whole pregnancy by using different thresholds, including low temperatures (< 25th, < 15th, < 10th, < 5th percentiles), and high temperatures (> 75th, > 85th, > 90th, > 95th percentiles). Three different approaches (generalized linear model, inverse probability weighting, and doubly robust model) were applied to estimate the effects of low/high temperatures on birth weight and placental indicators, including placental weight, placental volume, and placental-to-birth weight ratio (PFR), respectively. We observed that both low and high ambient temperatures during the whole pregnancy were associated with lower birth weight and negative changes in placental indicators. The estimated lower mean birth weight ranged from -158 g (95 % CI: -192 g, -123 g) to -363 g (95 % CI: -424 g, -301 g) for low temperatures and from -97 g (95 % CI: -135 g, -59 g) to -664 g (95 % CI: -742 g, -585 g) for high temperatures. In mediation analyses, placental weight mediated 28.79 % to 40.47 % and 48.22 % to 54.38 % of the association of low and high temperatures with birth weight, respectively. The findings suggest that placental weight may mediate the association between ambient temperature exposure and birth weight.

Sex differences in innate and adaptive immunity impact fetal, placental, and maternal health†

The differences between males and females begin shortly after birth, continue throughout prenatal development, and eventually extend into childhood and adult life. Male embryos and fetuses prioritize proliferation and growth, often at the expense of the fetoplacental energy reserves. This singular focus on growth over adaptability leaves male fetuses and neonates vulnerable to adverse outcomes during pregnancy and birth and can have lasting impacts throughout life. Beyond this prioritization of growth, male placentas and fetuses also respond to infection and inflammation differently than female counterparts. Pregnancies carrying female fetuses have a more regulatory immune response, whereas pregnancies carrying male fetuses have a stronger inflammatory response. These differences can be seen as early as the innate immune response with differences in cytokine and chemokine signaling. The sexual dimorphism in immunity then continues into the adaptive immune response with differences in T-cell biology and antibody production and transfer. As it appears that these sex-specific differences are amplified in pathologic pregnancies, it stands to reason that differences in the placental, fetal, and maternal immune responses in pregnancy contribute to increased male perinatal morbidity and mortality. In this review, we will describe the genetic and hormonal contributions to the sexual dimorphism of fetal and placental immunity. We will also discuss current research efforts to describe the sex-specific differences of the maternal-fetal interface and how it impacts fetal and maternal health.

Structure and Functions of HMGB2 Protein

High-Mobility Group (HMG) chromosomal proteins are the most numerous nuclear non-histone proteins. HMGB domain proteins are the most abundant and well-studied HMG proteins. They are involved in variety of biological processes. HMGB1 and HMGB2 were the first members of HMGB-family to be discovered and are found in all studied eukaryotes. Despite the high degree of homology, HMGB1 and HMGB2 proteins differ from each other both in structure and functions. In contrast to HMGB2, there is a large pool of works devoted to the HMGB1 protein whose structure-function properties have been described in detail in our previous review in 2020. In this review, we attempted to bring together diverse data about the structure and functions of the HMGB2 protein. The review also describes post-translational modifications of the HMGB2 protein and its role in the development of a number of diseases. Particular attention is paid to its interaction with various targets, including DNA and protein partners. The influence of the level of HMGB2 expression on various processes associated with cell differentiation and aging and its ability to mediate the differentiation of embryonic and adult stem cells are also discussed.

Structural Characteristics of High-Mobility Group Proteins HMGB1 and HMGB2 and Their Interaction with DNA

Non-histone nuclear proteins HMGB1 and HMGB2 (High Mobility Group) are involved in many biological processes, such as replication, transcription, and repair. The HMGB1 and HMGB2 proteins consist of a short N-terminal region, two DNA-binding domains, A and B, and a C-terminal sequence of glutamic and aspartic acids. In this work, the structural organization of calf thymus HMGB1 and HMGB2 proteins and their complexes with DNA were studied using UV circular dichroism (CD) spectroscopy. Post-translational modifications (PTM) of HMGB1 and HMGB2 proteins were determined with MALDI mass spectrometry. We have shown that despite the similar primary structures of the HMGB1 and HMGB2 proteins, their post-translational modifications (PTMs) demonstrate quite different patterns. The HMGB1 PTMs are located predominantly in the DNA-binding A-domain and linker region connecting the A and B domains. On the contrary, HMGB2 PTMs are found mostly in the B-domain and within the linker region. It was also shown that, despite the high degree of homology between HMGB1 and HMGB2, the secondary structure of these proteins is also slightly different. We believe that the revealed structural properties might determine the difference in the functioning of the HMGB1 and HMGB2 as well as their protein partners.

Recent insight into autophagy and immunity at the maternal-fetal interface

Autophagy is a lysosomal degradation pathway that supports metabolic adaptation and energy cycling. It is essential for cell homeostasis, differentiation, development, and survival. Recent studies have shown that autophagy could influence immune responses by regulating immune cell functions. Reciprocally, immune cells strongly influence autophagy. Immune cells at the maternal-fetal interface are thought to play essential roles in pregnancy. Here, we review the induction of autophagy at the maternal-fetal interface and its role in decidualization and placental development. Additionally, we emphasize the role of autophagy in the immune microenvironment at the maternal-fetal interface, including innate immunity, adaptive immunity, and immune tolerance molecules. It also suggests new research directions and prospects.

TMBIM4 Deficiency Facilitates NLRP3 Inflammasome Activation-Induced Pyroptosis of Trophoblasts: A Potential Pathogenesis of Preeclampsia

Impaired invasion of EVTs results in inadequate remodelling of arteries and poor placentation, leading to PE. TMBIM4 was found to promote the migration and invasion of human osteosarcoma U2-OS and breast cancer MCF7 cell lines. However, the effect of TMBIM4 on trophoblast biological behaviour and its relevance to PE pathophysiology remain unclear. In this study, we confirmed that TMBIM4 was highly expressed in cytotrophoblasts, syncytiotrophoblasts, and EVTs of the human placenta during early pregnancy. By comparing the expression levels of TMBIM4 in the placenta of women with normal-term pregnancy and PE, TMBIM4 was found to be significantly decreased in PE. Thereafter, we determined the expression of TMBIM4 in the LPS-treated first-trimester human trophoblast cell line HTR-8/SVneo (mimicking a PE-like cell model), and determined the effect of TMBIM4 on trophoblast function and its underlying mechanism. LPS treatment reduced the expression of TMBIM4 and induced NLRP3 inflammasome activity in HTR-8/SVneo cells. KO of TMBIM4 in the HTR-8/SVneo cell line impaired cell viability, migration, and invasion, which was more severe in the LPS/ATP-treated TMBIM4-KO cell line. Moreover, TMBIM4 deficiency enhanced NLRP3 inflammasome activity and promoted subsequent pyroptosis, with or without LPS/ATP treatment. The negative relationship between TMBIM4 expression and NLRP3 inflammatory activity was verified in PE placentas. Inhibiting the NLRP3 inflammasome with MCC950 in HTR-8/SVneo cells alleviated LPS/ATP-induced pyroptosis and damaged cell function in the TMBIM4-KO cell line. Overall, this study revealed a new PE-associated protein, TMBIM4, and its biological significance in trophoblast pyroptosis mediated by the NLRP3 inflammasome. TMBIM4 may serve as a potential target for the treatment of placental inflammation-associated PE.

Placental circadian lincRNAs and spontaneous preterm birth

Long non-coding RNAs (lncRNAs) have a much higher cell- and/or tissue-specificity compared to mRNAs in most cases, making them excellent candidates for therapeutic applications to reduce off-target effects. Placental long non-coding RNAs have been investigated in the pathogenesis of preeclampsia (often causing preterm birth (PTB)), but less is known about their role in preterm birth. Preterm birth occurs in 11% of pregnancies and is the most common cause of death among infants in the world. We recently identified that genes that drive circadian rhythms in cells, termed molecular clock genes, are deregulated in maternal blood of women with spontaneous PTB (sPTB) and in the placenta of women with preeclampsia. Next, we focused on circadian genes-correlated long intergenic non-coding RNAs (lincRNAs, making up most of the long non-coding RNAs), designated as circadian lincRNAs, associated with sPTB. We compared the co-altered circadian transcripts-correlated lincRNAs expressed in placentas of sPTB and term births using two published independent RNAseq datasets (GSE73712 and GSE174415). Nine core clock genes were up- or downregulated in sPTB versus term birth, where the RORA transcript was the only gene downregulated in sPTB across both independent datasets. We found that five circadian lincRNAs (LINC00893, LINC00265, LINC01089, LINC00482, and LINC00649) were decreased in sPTB vs term births across both datasets (p ≤ .0222, FDR≤.1973) and were negatively correlated with the dataset-specific clock genes-based risk scores (correlation coefficient r = -.65 ∼ -.43, p ≤ .0365, FDR≤.0601). Gene set variation analysis revealed that 65 pathways were significantly enriched by these same five differentially expressed lincRNAs, of which over 85% of the pathways could be linked to immune/inflammation/oxidative stress and cell cycle/apoptosis/autophagy/cellular senescence. These findings may improve our understanding of the pathogenesis of spontaneous preterm birth and provide novel insights into the development of potentially more effective and specific therapeutic targets against sPTB.

Ambient fine particulate matter exposures and human early placental inflammation

The effect of fine particulate matter (PM_2.5) on human early maternal-fetal interface is unknown. We explored the association between maternal exposure to ambient PM_2.5 and inflammation in placental villus of 114 women with clinically recognized early pregnancy loss (CREPL) and 114 women with normal early pregnancy (NEP). Temporally-adjusted land use regression models were used to estimate maternal daily PM_2.5 exposure during pregnancy. Villus interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were measured using multiplex cytokines detection platform. Single-day lag effect of PM_2.5 exposure within ten days before early placental villus collection was estimated using multivariable linear regression model. Distributed lag and net cumulative effects of PM_2.5 exposures within ten and 30 days before villus collection, as well as five single weeks during the periovulatory period, were estimated using distributed lag non-linear models. In all 228 subjects, after adjusting for group (CREPL or NEP), temporal confounders, and demographic characteristics, both single-day and distributed lag effects of PM_2.5 exposure at lag 8 significantly increased villus IL-6; distributed lag effects of PM_2.5 exposure in the first and second weeks before ovulation increased IL-1β, and PM_2.5 exposure in the third week after ovulation increased IL-6 and TNF-α. In CREPL, single-day lag effect significantly increased IL-1β (at lag 1), IL-6 (at lag 8), and TNF-α (at lag 5); distributed lag effect increased IL-6 (at lag 4-lag 8) and TNF-α (at lag 4-lag 6); and cumulative effect within ten days before villus collection increased IL-6. There was no statistically significant cumulative effect in NEP. In summary, maternal PM_2.5 exposure was associated with placental inflammation in human early pregnancy, particularly with increased villus IL-6 in CREPL. Whether maternal-fetal interface inflammation related to PM_2.5 exposure during the periovulatory period or later contributes to CREPL or other adverse pregnancy outcomes requires further study.

Placental findings in singleton stillbirths: a case-control study from a tertiary-care center in India

OBJECTIVES

Placental examination in a case of stillbirth can provide insight into causative/associated factors with fetal demise. The aim of this study was to compare placental and umbilical cord pathologies in singleton stillbirth and livebirth placentas, and to find prevalence of various associated maternal and fetal clinical factors.

METHODS

This case-control study was conducted at a tertiary-care center in India over a period of 20 months. About 250 women who delivered stillborn fetus ≥28 weeks' gestation and 250 maternal-age-matched controls were recruited. Sociodemographic and clinical details were noted and placental gross and microscopic examination was done. Placental findings were compared between stillbirth and livebirth (overall), preterm stillbirth and preterm livebirth as well as term stillbirth and term livebirth in six categories - placenta gross, cord gross, membranes gross, maternal vascular malperfusion, fetal vascular malperfusion and inflammatory response. Prevalence of 11 maternal and fetal factors were studied in all categories of placental findings in both livebirth and stillbirth.

RESULTS

Placental findings in all six categories were significantly associated with stillbirths (p<0.05). The placental findings associated with stillbirth with highest odds included placental hypoplasia (OR 9.77, 95% CI 5.46-17.46), necrotizing chorioamnionitis (OR 9.30, 95% CI 1.17-73.96) and avascular villi (OR 8.45, 95% CI 3.53-20.25). More than half of the women with stillbirths had medical disorders (n=130, 52.0%) and the most prevalent was hypertensive disorder (n=45, 18.0%).

CONCLUSIONS

Changes in placenta are associated with development of stillbirth. Therefore, antenatal investigations to identify placental dysfunction should be investigated to determine whether these reduce stillbirth. Also, placental examination in a case of stillbirth can detect/diagnose many maternal/fetal conditions and thereby can help in preventing future stillbirths.

Modulatory effect of two regimens of magnesium sulfate on the systemic inflammatory response in pregnant women with imminent eclampsia

OBJECTIVE

This study compared the modulatory effect of two intravenous magnesium sulfate (MgSO₄) regimens on the systemic inflammatory response in pregnant women diagnosed with imminent eclampsia.

STUDY DESIGN

In a single-blind cross-sectional study, 33 women were allocated according to the Zuspan (n = 16) and Sibai (n = 17) MgSO₄ regimens, and treated for 24 h. Blood samples were collected pre-administration of the loading dose, at 24 h of the maintenance dose of MgSO₄, and at 48 h, when patients were without treatment. Plasma was used to determine interleukin (IL)-1 beta (IL-1β), IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), heat shock protein (Hsp70), and heme oxygenase-1 (HO-1) by ELISA.

RESULTS

The treatment with the Zuspan's regimen didn't change plasma concentrations of TNF-α, IL-10, and Hsp70 in the three-time points studied. However, it decreased IL-1β at 24 h and 48 h and IL-6 at 48 h, and increased HO-1 concentration at 48 h. On the other hand, compared to the pre-treatment period, Sibai's regimen induced a significant decrease in TNF-α, IL-1β, IL-6, and Hsp70, while increased HO-1 levels both at 24 h and 48 h and, IL-10 concentration at 48 h.

CONCLUSIONS

Sibai's regimen determined an early and efficient immunoregulatory effect on systemic inflammatory response in preeclampsia, suggesting that the maintenance dose of two grams of MgSO₄ was better than one gram in the treatment of imminent eclampsia.

Spontaneous embryonic death in plains viscacha (Lagostomus maximus - Rodentia), a species with unique reproductive characteristics

Spontaneous embryonic death is a conserved reproductive event in Eutherians. The macro and microscopic characteristics of this type of death are similar between the different taxa. However, in the hystricomorphic rodent plains viscacha (Lagostomus maximus) is exceptional in terms of massiveness (80% embryonic resorption). In this species, of the 10-12 implantation sites (IS) (half in each uterine horn), only the caudal embryos will survive, resorbing the cranial and intermediate IS. We hypothesize that uterine structural variations in L. maximus restrict growth and promote embryo death, with the consequent loss of placental homeostasis in the cranial and middle IS. In this study, different studies (ultrasonography, macroscopy and microscopy) were carried out to analyze different aspects of the intermediate gestation of L. maximus (46 days postcoitus). Ultrasonographic studies revealed that the cranial and middle IS (IS-1, IS-2, and IS-3) had no recognizable embryonic and placental structures as compared to the caudal implantation sites (IS-4). Macroscopically, the areas corresponding to the embryos in the cranial and middle IS were occupied by a necrotic black semi-fluid mass. Moreover, the placenta in these IS was undifferentiated. However, in the caudal IS both the embryo and its placenta were distinguishable. Using histological and immunohistochemical techniques, it was observed that the placentas of IS-1, IS-2 and IS-3 were disorganized and showed hemorrhage, inflammatory infiltration containing neutrophils, macrophages, mast cells and foreign body giant cells, apoptotic trophoblast, and a layer of collagen fibers and fibroblasts that circumscribed each of these IS. In contrast, the placenta of the caudal IS showed an organized maternal-embryonic interface. The characteristics observed in IS in resorption of viscachas in intermediate gestation show that, regardless of gestation time, embryonic death has a similar macro and microscopic morphological pattern among eutherians with invasive placentation. However, the massiveness and sectorization of embryonic death in the plains viscacha make the species a unique model for the study of this reproductive event.

Predictive value of NLR and PLR in missed miscarriage

Background

The aim of the study was to investigate the predictive value of neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) in missed miscarriage.

Methods

In this retrospective cohort study, a total of 400 women (involving 200 with missed early miscarriage and 200 with normal pregnancy but terminate by artificial abortion) were included. General clinical data and complete blood count (CBC) such as white blood cells (WBC), red blood cells (RBC), platelet (PLT), red blood cell distribution width‐standard deviation (RDW‐SD), platelet distribution width (PDW), mean platelet volume (MPV), neutrophil count, and lymphocyte count were collected, and the NLR and PLR were calculated for both groups. Receiver operating characteristic curve (ROC) was used to calculate the predictive value.

Results

There was no significant difference in the WBC, RBC, PLT, RDW‐SD, PDW, neutrophil, lymphocyte, NLR, and PLR between the two groups (p > 0.05).But MPV was lower in the missed early miscarriage group than in the control group (p < 0.05), and the area under the working curve (AUC) of ROC was 0.58, specificity and sensitivity was 69% and 47%, respectively.

Conclusion

NLR and PLR were not the suitable indictor for missed miscarriage, but MPV should be a concern in the first trimester.

A Systematic Review of the Safety of Blocking the IL-1 System in Human Pregnancy

Blockade of the interleukin-1 (IL-1) pathway has been used therapeutically in several inflammatory diseases including arthritis and cryopyrin-associated periodic syndrome (CAPS). These conditions frequently affect women of childbearing age and continued usage of IL-1 specific treatments throughout pregnancy has been reported. IL-1 is involved in pregnancy complications and its blockade could have therapeutic potential. We systematically reviewed all reported cases of IL-1 blockade in human pregnancy to assess safety and perinatal outcomes. We searched several databases to find reports of specific blockade of the IL-1 pathway at any stage of pregnancy, excluding broad spectrum or non-specific anti-inflammatory intervention. Our literature search generated 2439 references of which 22 studies included, following extensive review. From these, 88 different pregnancies were assessed. Most (64.8%) resulted in healthy term deliveries without any obstetrical/neonatal complications. Including pregnancy exposed to Anakinra or Canakinumab, 12 (15.0%) resulted in preterm birth and one stillbirth occurred. Regarding neonatal complications, 2 cases of renal agenesis (2.5%) were observed, and 6 infants were diagnosed with CAPS (7.5%). In conclusion, this systematic review describes that IL-1 blockade during pregnancy is not associated with increased adverse perinatal outcomes, considering that treated women all presented an inflammatory disease associated with elevated risk of pregnancy complications.

Prenatal administration of IL-1Ra attenuate the neurodevelopmental impacts following non-pathogenic inflammation during pregnancy

Prenatal inflammation negatively affects placental function, subsequently altering fetal development. Pathogen-associated molecular patterns (PAMPs) are used to mimics infections in preclinical models but rarely detected during pregnancy. Our group previously developed an animal model of prenatal exposure to uric acid (endogenous mediator), leading to growth restriction alongside IL-1-driven placental inflammation (Brien et al. in J Immunol 198(1):443–451, 2017). Unlike PAMPs, the postnatal impact of prenatal non-pathogenic inflammation is still poorly understood. Therefore, we investigated the effects of prenatal uric acid exposure on postnatal neurodevelopment and the therapeutic potential of the IL-1 receptor antagonist; IL-1Ra. Uric acid induced growth restriction and placental inflammation, which IL-1Ra protected against. Postnatal evaluation of both structural and functional aspects of the brain revealed developmental changes. Both astrogliosis and microgliosis were observed in the hippocampus and white matter at postnatal day (PND)7 with IL-1Ra being protective. Decreased myelin density was observed at PND21, and reduced amount of neuronal precursor cells was observed in the Dentate Gyrus at PND35. Functionally, motor impairments were observed as evaluated with the increased time to fully turn upward (180 degrees) on the inclined plane and the pups were weaker on the grip strength test. Prenatal exposure to sterile inflammation, mimicking most clinical situation, induced growth restriction with negative impact on neurodevelopment. Targeted anti-inflammatory intervention prenatally could offer a strategy to protect brain development during pregnancy.

Vitamin D modulates the transcription factors of T cell subsets to anti-inflammatory and regulatory profiles in preeclampsia

Vitamin D (VD) is a multifunctional prohormone and low VD status in pregnancy may contribute to the risk of adverse perinatal outcomes, such as preeclampsia (PE). This molecule may modulate the polarization of T cell subsets during gestation. This study evaluated the in vitro immunomodulatory effect of VD [1,25(OH)₂D₃] on the gene expression of transcription factors and on cytokine production by T cell subsets. Twenty pregnant women with PE and twenty normotensive (NT) pregnant women were studied. Plasma concentration of VD, [25(OH)D₃], was evaluated by chemiluminescence. PBMCs from preeclamptic and NT pregnant women were cultured in the absence or presence of VD to determine gene expression of T-bet (Th1), GATA-3 (Th2), RORγt, and RUNX1 (Th17), FoxP3 (regulatory T cell- Treg), and the receptors of VD (VDR) and IL-23 (IL-23R) by quantitative PCR. The concentration of cytokines in the PBMC supernatant culture was determined by cytometric bead array and ELISA immunoassay. The results showed that plasmatic levels of VD were significantly lower in the PE group. The treatment of PBMCs from PE pregnant women with VD induced downregulation of genes related to inflammatory profiles (Th1 and Th17), as well as an increase of the Th2 and Treg profiles. Thus, VD treatment decreased the release of IFN-γ, TNF-α, IL-17, IL-6, and IL-23 while it increased the levels of IL-10 in the PE group. VD induces an immunomodulatory effect in T cell subsets from pregnant women with PE, polarizing these cells to an anti-inflammatory and regulatory profile.

Association between proteinuria and placental pathology in preeclampsia: A retrospective study

Introduction:

Preeclampsia develops due to placental insufficiency and systemic proinflammatory and antiangiogenic mediator release, with ensuing systemic endothelial dysfunction. Nephrotic-range proteinuria appears to be associated with worse pregnancy outcomes. The relationship between differing degrees of proteinuria and the severity of placental alterations has not been studied.

Methods:

This is a single-centre retrospective comparison of 150 singleton pregnancies complicated by preeclampsia and varying degrees of proteinuria. Maternal demographic, obstetrical and fetal outcome data were obtained from chart review. The placental histologic evaluations were performed by a placental pathologist blinded to all other clinical information.

Results:

Preeclamptic women with massive proteinuria had evidence of more severe maternal vascular malperfusion lesions. The severity of the lesions was progressive through mild, moderate and massive proteinuria. Women with massive proteinuria had a higher incidence of renal dysfunction and severe hypertension, and had earlier preterm deliveries compared to preeclamptic women with mild and moderate proteinuria (p < 0.05).

Conclusion:

Preeclampsia with more severe proteinuria is associated with a higher prevalence of placental maternal vascular malperfusion.

Etiological Value of Sterile Inflammation in Preeclampsia: Is It a Non-Infectious Pregnancy Complication?

Understanding of sterile inflammation and its associated biological triggers and diseases is still at the elementary stage. This becomes more warranted in cases where infections are not associated with the pathology. Detrimental effects of bacterial and viral infections on the immune responses at the maternal-fetal interface as well as pregnancy outcomes have been well documented. However, an infection-induced etiology is not thought to be a major contributing component to severe pregnancy complications such as preeclampsia (PE) and gestational diabetes. How is then an inflammatory signal thought to be associated with these pregnancy complications? It is not clear what type of inflammation is involved in the onset of PE-like features. We opine that sterile inflammation regulated by the inflammasome-gasdermins-caspase-1 axis is a contributory factor to the onset of PE. We hypothesize that increased production and release of damage-associated molecular patterns (DAMPs) or Alarmins such as high-mobility group box1 (HMGB1), cell-free fetal DNA, uric acid, the NOD-like receptor pyrin-containing receptor 3 (NLRP3) inflammasome, IL-1β and IL-18 occur in the PE placenta. Some of these molecules have already been observed in the placenta from women with PE. Mechanistically, emerging evidence has demonstrated that excessive placental endoplasmic reticulum (ER) stress, impaired autophagy and gasdermine D (GSDMD)-mediated intrinsic pyroptosis are key events that contribute to systemic sterile inflammation in patients with PE, especially early-onset PE (e-PE). In this review, we highlight the advances on the roles of sterile inflammation and inflammatory signaling cascades involving ER stress, autophagy deficiency and pyroptosis in PE pathophysiology. Deciphering the mechanisms underlying these inflammatory pathways may provide potential diagnostic biomarkers and facilitate the development of therapeutic strategies to treat this devastating disease.

Hofbauer Cells Spread Listeria monocytogenes among Placental Cells and Undergo Pro-Inflammatory Reprogramming while Retaining Production of Tolerogenic Factors

Pregnant women are highly susceptible to infection by the bacterial pathogen Listeria monocytogenes, leading to miscarriage, premature birth, and neonatal infection. L. monocytogenes is thought to breach the placental barrier by infecting trophoblasts at the maternal/fetal interface. However, the fate of L. monocytogenes within chorionic villi and how infection reaches the fetus are unsettled. Hofbauer cells (HBCs) are fetal placental macrophages and the only leukocytes residing in healthy chorionic villi, forming a last immune barrier protecting fetal blood from infection. Little is known about the HBCs’ antimicrobial responses to pathogens. Here, we studied L. monocytogenes interaction with human primary HBCs. Remarkably, despite their M2 anti-inflammatory phenotype at basal state, HBCs phagocytose and kill non-pathogenic bacteria like Listeria innocua and display low susceptibility to infection by L. monocytogenes. However, L. monocytogenes can exploit HBCs to spread to surrounding placental cells. Transcriptomic analyses by RNA sequencing revealed that HBCs undergo pro-inflammatory reprogramming upon L. monocytogenes infection, similarly to macrophages stimulated by the potent M1-polarizing agents lipopolysaccharide (LPS)/interferon gamma (IFN-γ). Infected HBCs also express pro-inflammatory chemokines known to promote placental infiltration by maternal leukocytes. However, HBCs maintain the expression of a collection of tolerogenic genes and secretion of tolerogenic cytokines, consistent with their tissue homeostatic role in prevention of fetal rejection. In conclusion, we propose a previously unrecognized model in which HBCs promote the spreading of L. monocytogenes among placental cells and transition to a pro-inflammatory state likely to favor innate immune responses, while maintaining the expression of tolerogenic factors known to prevent maternal anti-fetal adaptive immunity.

Ambient air pollution and stillbirth: An updated systematic review and meta-analysis of epidemiological studies

Stillbirth has a great impact on contemporary and future generations. Increasing evidence show that ambient air pollution exposure is associated with stillbirth. However, previous studies showed inconsistent findings. To clarify the effect of maternal air pollution exposure on stillbirth, we searched for studies examining the associations between air pollutants, including particulate matter (diameter ≤ 2.5 μm [PM_2.5] and ≤10 μm [PM₁₀]) and gaseous pollutants (sulfur dioxide [SO₂], nitrogen dioxide [NO₂], carbon monoxide [CO] and ozone [O₃]), and stillbirth published in PubMed, Web of Science, Embase and Cochrane Library until December 11, 2020. The pooled effect estimates and 95% confidence intervals (CI) were calculated, and the heterogeneity was evaluated using Cochran's Q test and I² statistic. Publication bias was assessed using funnel plots and Egger's tests. Of 7546 records, 15 eligible studies were included in this review. Results of long-term exposure showed that maternal third trimester PM_2.5 and CO exposure (per 10 μg/m³ increment) increased the odds of stillbirth, with estimated odds ratios (ORs) of 1.094 (95% CI: 1.008-1.180) and 1.0009 (95% CI: 1.0001-1.0017), respectively. Entire pregnancy exposure to PM_2.5 was also associated with stillbirth (OR: 1.103, 95% CI: 1.074-1.131). A 10 μg/m³ increment in O₃ in the first trimester was associated with stillbirth, and the estimated OR was 1.028 (95% CI: 1.001-1.055). Short-term exposure (on lag day 4) to O₃ was also associated with stillbirth (OR: 1.002, 95% CI: 1.001-1.004). PM₁₀, SO₂ and NO₂ exposure had no significant effects on the incidence of stillbirth. Additional well-designed cohort studies and investigations regarding potential biological mechanisms are warranted to elaborate the suggestive association that may help improve intergenerational inequality.

Maternal respiratory SARS-CoV-2 infection in pregnancy is associated with a robust inflammatory response at the maternal-fetal interface

BACKGROUND

Pregnant women are at increased risk for severe outcomes from coronavirus disease 2019 (COVID-19), but the pathophysiology underlying this increased morbidity and its potential effect on the developing fetus is not well understood.

METHODS

We assessed placental histology, ACE2 expression, and viral and immune dynamics at the term placenta in pregnant women with and without respiratory severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

FINDINGS

The majority (13 of 15) of placentas analyzed had no detectable viral RNA. ACE2 was detected by immunohistochemistry in syncytiotrophoblast cells of the normal placenta during early pregnancy but was rarely seen in healthy placentas at full term, suggesting that low ACE2 expression may protect the term placenta from viral infection. Using immortalized cell lines and primary isolated placental cells, we found that cytotrophoblasts, the trophoblast stem cells and precursors to syncytiotrophoblasts, rather than syncytiotrophoblasts or Hofbauer cells, are most vulnerable to SARS-CoV-2 infection in vitro. To better understand potential immune mechanisms shielding placental cells from infection in vivo, we performed bulk and single-cell transcriptomics analyses and found that the maternal-fetal interface of SARS-CoV-2-infected women exhibited robust immune responses, including increased activation of natural killer (NK) and T cells, increased expression of interferon-related genes, as well as markers associated with pregnancy complications such as preeclampsia.

CONCLUSIONS

SARS-CoV-2 infection in late pregnancy is associated with immune activation at the maternal-fetal interface even in the absence of detectable local viral invasion.

FUNDING

NIH (T32GM007205, F30HD093350, K23MH118999, R01AI157488, U01DA040588) and Fast Grant funding support from Emergent Ventures at the Mercatus Center.

Neurology of Preeclampsia and Related Disorders: an Update in Neuro-obstetrics

PURPOSE OF REVIEW

Preeclampsia and related hypertensive disorders of pregnancy affect up to 10% of pregnancies. Neurological complications are common and neurologists often become involved in the care of obstetric patients with preeclampsia. Here, we review the definition(s), epidemiology, clinical features, and pathophysiology of preeclampsia, focusing on maternal neurological complications and headache as a common presenting symptom of preeclampsia.

RECENT FINDINGS

Neurological symptoms are early and disease-defining features of preeclampsia. Neurological complications of preeclampsia may include headaches, visual symptoms, cerebral edema, seizures, or acute cerebrovascular disorders such as intracerebral hemorrhage or reversible cerebral vasoconstriction syndrome. A history of migraine is an independent risk factor for vascular diseases during pregnancy, including preeclampsia and maternal stroke. The pathophysiology of both preeclampsia and migraine is complex, and the mechanisms linking the two are not fully understood. Overlapping clinical and pathophysiological features of migraine and preeclampsia include inflammation, vascular endothelial dysfunction, and changes in vasoreactivity. Neurological complications are recognized as a major contributor to maternal morbidity and mortality. Pregnant and postpartum women commonly present with headache, and red flags in the clinical history and examination should prompt urgent neuroimaging and laboratory evaluation. A focused headache history should be elicited from patients as part of routine obstetrical care to identify patients at an increased risk of preeclampsia and related hypertensive disorders of pregnancy. Collaborative models of care and scientific investigation in the emerging field of neuro-obstetrics have the common goal of reducing the risk of maternal neurological morbidity and mortality from preeclampsia.

Hypoxia and oxidative stress induce sterile placental inflammation in vitro

Fetal growth restriction (FGR) and stillbirth are associated with placental dysfunction and inflammation and hypoxia, oxidative and nitrative stress are implicated in placental damage. Damage-associated molecular patterns (DAMPs) are elevated in pregnancies at increased risk of FGR and stillbirth and are associated with increase in pro-inflammatory placental cytokines. We hypothesised that placental insults lead to release of DAMPs, promoting placental inflammation. Placental tissue from uncomplicated pregnancies was exposed in vitro to hypoxia, oxidative or nitrative stress. Tissue production and release of DAMPs and cytokines was determined. Oxidative stress and hypoxia caused differential release of DAMPs including uric acid, HMGB1, S100A8, cell-free fetal DNA, S100A12 and HSP70. After oxidative stress pro-inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, TNFα, CCL2) were increased both within explants and in conditioned culture medium. Hypoxia increased tissue IL-1α/β, IL-6, IL-8 and TNFα levels, and release of IL-1α, IL-6 and IL-8, whereas CCL2 and IL-10 were reduced. IL1 receptor antagonist (IL1Ra) treatment prevented hypoxia- and oxidative stress-induced IL-6 and IL-8 release. These findings provide evidence that relevant stressors induce a sterile inflammatory profile in placental tissue which can be partially blocked by IL1Ra suggesting this agent has translational potential to prevent placental inflammation evident in FGR and stillbirth.

Progesterone and vitamin D downregulate the activation of the NLRP1/NLRP3 inflammasomes and TLR4-MyD88-NF-κB pathway in monocytes from pregnant women with preeclampsia

This study evaluated the in vitro modulatory effect of progesterone (PG) and vitamin D (VD) on NLRP1/NLRP3 inflammasomes and TLR4/NF-κB pathway in monocytes from pregnant women with preeclampsia (PE). Monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, and THP-1 cells were cultured with/without hyaluronan (HA), PG, or VD to determine gene and protein expression of TLR4 receptor, phosphorylated NF-κB, IκBα, TLR4, MYD88, NF-κB, NLRP1, NLRP3, caspase-1, IL-1β, IL-18, TNF-α, and IL-10. Higher endogenous activation of inflammatory genes and higher protein expression of TLR4 and NF-κB was detected in monocytes of PE group and decreased after PG or VD treatment. Monocyte from PE stimulated with HA increased while treatment with PG or VD decreased the expression of genes and proteins related to the inflammasomes. THP-1 cells showed a similar immune response profile as monocytes from PE. These results demonstrate that PG and VD play an immunomodulatory role in monocyte activation.

SARS-CoV-2 infection in pregnancy is associated with robust inflammatory response at the maternal-fetal interface

Pregnant women appear to be at increased risk for severe outcomes associated with COVID-19, but the pathophysiology underlying this increased morbidity and its potential impact on the developing fetus is not well understood. In this study of pregnant women with and without COVID-19, we assessed viral and immune dynamics at the placenta during maternal SARS-CoV-2 infection. Amongst uninfected women, ACE2 was detected by immunohistochemistry in syncytiotrophoblast cells of the normal placenta during early pregnancy but was rarely seen in healthy placentas at full term. Term placentas from women infected with SARS-CoV-2, however, displayed a significant increase in ACE2 levels. Using immortalized cell lines and primary isolated placental cells, we determined the vulnerability of various placental cell types to direct infection by SARS-CoV-2 in vitro. Yet, despite the susceptibility of placental cells to SARS-CoV-2 infection, viral RNA was detected in the placentas of only a subset (~13%) of women in this cohort. Through single cell transcriptomic analyses, we found that the maternal-fetal interface of SARS-CoV-2-infected women exhibited markers associated with pregnancy complications, such as preeclampsia, and robust immune responses, including increased activation of placental NK and T cells and increased expression of interferon-related genes. Overall, this study suggests that SARS-CoV-2 is associated with immune activation at the maternal-fetal interface even in the absence of detectable local viral invasion. While this likely represents a protective mechanism shielding the placenta from infection, inflammatory changes in the placenta may also contribute to poor pregnancy outcomes and thus warrant further investigation.

The Prenatal Hormone Milieu in Autism Spectrum Disorder

Though the etiology of autism spectrum disorder (ASD) remains largely unknown, recent findings suggest that hormone dysregulation within the prenatal environment, in conjunction with genetic factors, may alter fetal neurodevelopment. Early emphasis has been placed on the potential role of in utero exposure to androgens, particularly testosterone, to theorize ASD as the manifestation of an "extreme male brain." The relationship between autism risk and obstetric conditions associated with inflammation and steroid dysregulation merits a much broader understanding of the in utero steroid environment and its potential influence on fetal neuroendocrine development. The exploration of hormone dysregulation in the prenatal environment and ASD development builds upon prior research publishing associations with obstetric conditions and ASD risk. The insight gained may be applied to the development of chronic adult metabolic diseases that share prenatal risk factors with ASD. Future research directions will also be discussed.

Functional Diversity of Non-Histone Chromosomal Protein HmgB1

The functioning of DNA in the cell nucleus is ensured by a multitude of proteins, whose interactions with DNA as well as with other proteins lead to the formation of a complicated, organized, and quite dynamic system known as chromatin. This review is devoted to the description of properties and structure of the progenitors of the most abundant non-histone protein of the HMGB family-the HmgB1 protein. The proteins of the HMGB family are also known as "architectural factors" of chromatin, which play an important role in gene expression, transcription, DNA replication, and repair. However, as soon as HmgB1 goes outside the nucleus, it acquires completely different functions, post-translational modifications, and change of its redox state. Despite a lot of evidence of the functional activity of HmgB1, there are still many issues to be solved related to the mechanisms of the influence of HmgB1 on the development and treatment of different diseases-from oncological and cardiovascular diseases to pathologies during pregnancy and childbirth. Here, we describe molecular structure of the HmgB1 protein and discuss general mechanisms of its interactions with other proteins and DNA in cell.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

Specific inflammatory profile in each pregnancy complication: A comparative study

PROBLEM

Pre-eclampsia (PE), preterm birth (PTB) and intra-uterine growth restriction (IUGR) affect 5%-12% of pregnancies. They have been associated with placental inflammation, although the detection of inflammatory mediators in the maternal circulation is still controversial. Our goal was to determine the inflammatory changes occurring in the second part of pregnancy to identify profiles distinguishing pathological pregnancies from each other.

METHOD OF STUDY

We performed a nested case-control study of 200 women randomly selected from a cohort recruited at the CHU de Quebec-Universite Laval, Quebec, Canada. Women with uncomplicated term pregnancy (CTRL); PE (severe or not); PTB or IUGR (N = 50/each) were included. Plasma samples, obtained from the late second trimester and at delivery, were analysed for over 30 selected mediators (including cytokines/alarmins), by multiplex, ELISA or specific assays. Demographic and obstetrical information were obtained for classification.

RESULTS

In CTRL, we observed significant differences between 2nd trimester and delivery, with increased levels of inflammatory mediators (ex. MCP-1, IL-6), supporting an inflammatory profile towards term. Increased levels of IL-6, CXCL10 and CRP were observed in PE as compared to CTRL. In PTB, we observed increased CXCL9 in 2nd trimester and decreased progesterone at delivery. In IUGR, increased HMGB1 and IL-1α were observed only in the 2nd trimester.

CONCLUSIONS

Our work showed significant inflammatory changes in uncomplicated pregnancies towards delivery, supporting that normal delivery is pro-inflammatory, although not to the same extent as in pathological pregnancies. Inflammatory profiles are specific to each pregnancy complication which may help to understand the contribution of inflammation to the clinical presentation of these conditions.

Heme Oxygenase Protects against Placental Vascular Inflammation and Abortion by the Alarmin Heme in Mice

Both infectious as non-infectious inflammation can cause placental dysfunction and pregnancy complications. During the first trimester of human gestation, when palatogenesis takes place, intrauterine hematoma and hemorrhage are common phenomena, causing the release of large amounts of heme, a well-known alarmin. We postulated that exposure of pregnant mice to heme during palatogenesis would initiate oxidative and inflammatory stress, leading to pathological pregnancy, increasing the incidence of palatal clefting and abortion. Both heme oxygenase isoforms (HO-1 and HO-2) break down heme, thereby generating anti-oxidative and -inflammatory products. HO may thus counteract these heme-induced injurious stresses. To test this hypothesis, we administered heme to pregnant CD1 outbred mice at Day E12 by intraperitoneal injection in increasing doses: 30, 75 or 150 μmol/kg body weight (30H, 75H or 150H) in the presence or absence of HO-activity inhibitor SnMP from Day E11. Exposure to heme resulted in a dose-dependent increase in abortion. At 75H half of the fetuses where resorbed, while at 150H all fetuses were aborted. HO-activity protected against heme-induced abortion since inhibition of HO-activity aggravated heme-induced detrimental effects. The fetuses surviving heme administration demonstrated normal palatal fusion. Immunostainings at Day E16 demonstrated higher numbers of ICAM-1 positive blood vessels, macrophages and HO-1 positive cells in placenta after administration of 75H or SnMP + 30H. Summarizing, heme acts as an endogenous “alarmin” during pregnancy in a dose-dependent fashion, while HO-activity protects against heme-induced placental vascular inflammation and abortion.

Occurrence of a RAGE-Mediated Inflammatory Response in Human Fetal Membranes

Context:

Sterile inflammation has been shown to play a key role in the rupture of the fetal membranes (FMs). Moreover, an early and exacerbated runaway inflammation can evolve into a preterm premature rupture of membranes and lead to potential preterm birth. In this context, we investigated the receptor for advanced glycation end products (RAGE), an axis implied in physiological sterile inflammation, in conjunction with two major ligands: AGEs and High-Mobility Group Box 1 (HMGB1). Our first objective was to determine the spatiotemporal expression profiles of the different actors of the RAGE-signaling axis in human FMs, including its intracellular adaptors Diaphanous-1 and Myd88. Our second goal was to evaluate the functionality of RAGE signaling in terms of FMs inflammation.

Methods

The presence of the actors (RAGE, HMGB1, Myd88, and Diaphanous-1) at the mRNA level was investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in the human amnion and choriodecidua at the three trimesters and at term. Measurements were conducted at two distinct zones: the zone of intact morphology (ZIM) and the zone of altered morphology (ZAM). Then, proteins were quantified using Western blot analysis, and their localization was evaluated by immunofluorescence in term tissues. In addition, pro-inflammatory cytokine secretion was quantified using a Multiplex assay after the treatment of amnion and choriodecidua explants with two RAGE ligands (AGEs and HMGB1) in the absence or presence of a RAGE inhibitor (SAGEs).

Results

The FMs expressed the RAGE-signaling actors throughout pregnancy. At term, RNA and protein overexpression of the RAGE, HMGB1, and Diaphanous-1 were found in the amnion when compared to the choriodecidua, and the RAGE was overexpressed in the ZAM when compared to the ZIM. The two RAGE ligands (AGEs and HMGB1) induced differential cytokine production (IL1β and TNFα) in the amnion and choriodecidua.

Conclusion

Considered together, these results indicate that RAGE signaling is present and functional in human FMs. Our work opens the way to a better understanding of FMs weakening dependent on a RAGE-based sterile inflammation.

Antiphospholipid antibody-activated NETs exacerbate trophoblast and endothelial cell injury in obstetric antiphospholipid syndrome

Despite the widespread use of antiplatelets and anticoagulants, women with antiphospholipid syndrome (APS) may face pregnancy complications associated with placental dysplasia. Neutrophil extracellular traps (NETs) are involved in the pathogenesis of many autoimmune diseases, including vascular APS; however, their role in obstetric APS is unclear. Herein, we investigated the role of NETs by quantifying cell‐free DNA and NET marker levels. Live‐cell imaging was used to visualize NET formation, and MAPK signalling pathway proteins were analysed. Cell migration, invasion and tube formation assays were performed to observe the effects of NETs on trophoblasts and human umbilical vein endothelial cells (HUVECs). The concentrations of cell‐free DNA and NETs in sera of pregnant patients with APS were elevated compared with that of healthy controls (HCs) matched to gestational week. APS neutrophils were predisposed to spontaneous NET release and IgG purified from the patients (APS‐IgG) induced neutrophils from HCs to release NETs. Additionally, APS‐IgG NET induction was abolished with inhibitors of reactive oxygen species, AKT, p38 MAPK and ERK1/2. Moreover, NETs were detrimental to trophoblasts and HUVECs. In summary, APS‐IgG‐induced NET formation deserves further investigation as a potential novel therapeutic target in obstetrical APS.

Data-driven discovery of mid-pregnancy immune markers associated with maternal lifetime stress: results from an urban pre-birth cohort

Changes to the maternal inflammatory milieu may be a mechanism through which maternal psychosocial stress is transmitted to the fetus. Research investigating a limited number of immune markers may miss important signals. We take a proteomics approach to investigate maternal lifetime stress and 92 biomarkers of immune system status. Participants were enrolled in an urban, dual-site (Boston, n = 301 and New York City, n = 110) pregnancy cohort. We measured maternal lifetime history of stress and trauma using the validated Life Stressor Checklist-Revised (LSC-R). We measured a panel of 92 immune-related proteins in mid-pregnancy serum using proximity extension assay technology. We leveraged the dual-site study design to perform variable selection and inference within the cohort. First, we used LASSO to select immune markers related to maternal stress among Boston mothers. Then, we performed OLS regression to examine associations between maternal stress and LASSO-selected proteins among New York City mothers. LASSO regression selected 19 immune proteins with non-null coefficients (CCL11, CCL23, CD244, CST5, CXCL1, CXCL5, CXCL10, CX3CL1, FGF-23, IL-5, IL-7, IL-10, IL-17C, MCP-2, MMP-1, SLAMF1, ST1A1, TNF-β, and TWEAK). Of these, only the chemotactic cytokine CX3CL1 (i.e. fractalkine) was significantly associated with maternal stress among the validation sample (percent change in LSC-R score per 1% increase in relative fractalkine expression: 0.74, 95% confidence interval: 0.19, 1.28). Expanding research suggests fractalkine plays an important role in many aspects of pregnancy and fetal development and is stress-sensitive. We found that maternal lifetime history of stress and trauma was significantly associated with elevated serum fractalkine levels during pregnancy.

Innate and Adaptive Immune Responses in HELLP Syndrome

Innate and adaptive immune involvement in hemolysis, elevated liver enzymes and low platelet (HELLP) syndrome is an understudied field, although it is of high clinical importance. This syndrome implies a risk of serious morbidity and mortality to both the mother and the fetus during pregnancy. It was proposed that HELLP syndrome occurs in a circulatory inflammatory milieu, that might in turn participate in a complex interplay between the secreted inflammatory immunomodulators and immune cell surface receptors. Meanwhile, reported immune cell attenuation during HELLP may consequently lead to a prolonged immunoactivation and tissue damage. In this regard, learning more about the immune components of this syndrome should widen the understanding of the HELLP pathophysiology and eventually enable development of novel immune-based therapeutics. This review aims to summarize and discuss the recent and previous findings of the innate and adaptive immune responses during HELLP in order to update the current knowledge of the immune involvement in HELLP pathogenesis.

Destruction in maternal-fetal interface of URSA patients via the increase of the HMGB1-RAGE/TLR2/TLR4-NF-κB signaling pathway

AIMS

HMGB1 has been reported to play a crucial role in the physiological and pathophysiological responses during pregnancy. However, it is still unknown whether excessively expressed HMGB1 at the maternal-fetal interface related to Unexplained Recurrent Spontaneous Abortion (URSA). This study was designed to investigate the local capability of HMGB1 in the pathology of URSA, determined the distributions and characteristics of HMGB1, its receptors (RAGE/TLR2/TLR4) and important signaling molecule NF-κB p65 expression at the maternal-fetal interface，as well as compared the differences of HMGB1 expression between the URSA group, control group and aspirin treatment group.

MATERIAL AND METHODS

H&E staining, Western blot analysis, immunofluorescence assay and immunohistochemical staining were applied to determine the effect of HMGB1 and its receptors at the maternal-fetal interface. ELISA was utilized to detect the concentration of HMGB1 in plasma.

KEY FINDINGS

Our study demonstrated that the activation of the HMGB1-RAGE/TLR2/TLR4-NF-κB pathway at the maternal-fetal interface may have occurred in the URSA group. HMGB1 concentration in plasma was higher in the URSA group than the control group. Furthermore, the levels of HMGB1 of subjects with URSA could be reduced by administrating low doses of aspirin (ASPL).

SIGNIFICANCE

This is the first report indicating the roles of HMGB1 at the maternal-fetal interface of URSA patients and broadening the horizons for clinical treatment of URSA. HMGB1-RAGE/TLR2/TLR4-NF-κB signaling pathway may be activated at the maternal-fetal interface in URSA and account for its pathogenesis. HMGB1 have the potential to be promising biomarkers in prevention and therapy of URSA.

Role of the Monocyte-Macrophage System in Normal Pregnancy and Preeclampsia

The proper functioning of the monocyte-macrophage system, an important unit of innate immunity, ensures the normal course of pregnancy. In this review, we present the current data on the origin of the monocyte-macrophage system and its functioning in the female reproductive system during the ovarian cycle, and over the course of both normal and complicated pregnancy. Preeclampsia is a crucial gestation disorder characterized by pronounced inflammation in the maternal body that affects the work of the monocyte-macrophage system. The effects of inflammation at preeclampsia manifest in changes in monocyte counts and their subset composition, and changes in placental macrophage counts and their polarization. Here we summarize the recent data on this issue for both the maternal organism and the fetus. The influence of estrogen on macrophages and their altered levels in preeclampsia are also discussed.

Initiation of human parturition: signaling from senescent fetal tissues via extracellular vesicle mediated paracrine mechanism

A better understanding of the underlying mechanisms by which signals from the fetus initiate human parturition is required. Our recent findings support the core hypothesis that oxidative stress (OS) and cellular senescence of the fetal membranes (amnion and chorion) trigger human parturition. Fetal membrane cell senescence at term is a natural physiological response to OS that occurs as a result of increased metabolic demands by the maturing fetus. Fetal membrane senescence is affected by the activation of the p38 mitogen activated kinase-mediated pathway. Similarly, various risk factors of preterm labor and premature rupture of the membranes also cause OS-induced senescence. Data suggest that fetal cell senescence causes inflammatory senescence-associated secretory phenotype (SASP) release. Besides SASP, high mobility group box 1 and cell-free fetal telomere fragments translocate from the nucleus to the cytosol in senescent cells, where they represent damage-associated molecular pattern markers (DAMPs). In fetal membranes, both SASPs and DAMPs augment fetal cell senescence and an associated ‘sterile’ inflammatory reaction. In senescent cells, DAMPs are encapsulated in extracellular vesicles, specifically exosomes, which are 30–150 nm particles, and propagated to distant sites. Exosomes traffic from the fetus to the maternal side and cause labor-associated inflammatory changes in maternal uterine tissues. Thus, fetal membrane senescence and the inflammation generated from this process functions as a paracrine signaling system during parturition. A better understanding of the premature activation of these signals can provide insights into the mechanisms by which fetal signals initiate preterm parturition.