Distinct Cellular Immune Responses to SARS-CoV-2 in Pregnant Women.

Pregnant women are at increased risk of adverse outcomes, including preeclampsia and preterm birth, that may result from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Pregnancy imprints specific maternal immune responses that can modulate host susceptibility to microbial infection; therefore, recent studies have focused on the humoral response against SARS-CoV-2 in pregnant women. However, the pregnancy-specific cellular immune responses triggered by SARS-CoV-2 infection are poorly understood. In this study, we undertook an extensive in vitro investigation to determine the cellular immune responses to SARS-CoV-2 particles and proteins/peptides in pregnant women. First, we show that SARS-CoV-2 particles do not alter the pregnancy-specific oxidative burst of neutrophils and monocytes. Yet, SARS-CoV-2 particles/proteins shift monocyte activation from the classical to intermediate states in pregnant, but not in nonpregnant, women. Furthermore, SARS-CoV-2 proteins, but not particles or peptide pools, mildly enhance T cell activation during pregnancy. As expected, B cell phenotypes are heavily modulated by SARS-CoV-2 particles in all women; yet, pregnancy itself further modified such responses in these adaptive immune cells. Lastly, we report that pregnancy itself governs cytokine responses in the maternal circulation, of which IFN-ß and IL-8 were diminished upon SARS-CoV-2 challenge. Collectively, these findings highlight the differential in vitro responses to SARS-CoV-2 in pregnant and nonpregnant women and shed light on the immune mechanisms implicated in coronavirus disease 2019 during pregnancy.

Differential immunophenotype of circulating monocytes from pregnant women in response to viral ligands.

BACKGROUND: Viral infections during pregnancy can have deleterious effects on mothers and their offspring. Monocytes participate in the maternal host defense against invading viruses; however, whether pregnancy alters monocyte responses is still under investigation. Herein, we undertook a comprehensive in vitro study of peripheral monocytes to characterize the differences in phenotype and interferon release driven by viral ligands between pregnant and non-pregnant women. METHODS: Peripheral blood was collected from third-trimester pregnant (n = 20) or non-pregnant (n = 20, controls) women. Peripheral blood mononuclear cells were isolated and exposed to R848 (TLR7/TLR8 agonist), Gardiquimod (TLR7 agonist), Poly(I:C) (HMW) VacciGrade™ (TLR3 agonist), Poly(I:C) (HMW) LyoVec™ (RIG-I/MDA-5 agonist), or ODN2216 (TLR9 agonist) for 24 h. Cells and supernatants were collected for monocyte phenotyping and immunoassays to detect specific interferons, respectively. RESULTS: The proportions of classical (CD14hiCD16-), intermediate (CD14hiCD16+), non-classical (CD14loCD16+), and CD14loCD16- monocytes were differentially affected between pregnant and non-pregnant women in response to TLR3 stimulation. The proportions of pregnancy-derived monocytes expressing adhesion molecules (Basigin and PSGL-1) or the chemokine receptors CCR5 and CCR2 were diminished in response to TLR7/TLR8 stimulation, while the proportions of CCR5- monocytes were increased. Such differences were found to be primarily driven by TLR8 signaling, rather than TLR7. Moreover, the proportions of monocytes expressing the chemokine receptor CXCR1 were increased during pregnancy in response to poly(I:C) stimulation through TLR3, but not RIG-I/MDA-5. By contrast, pregnancy-specific changes in the monocyte response to TLR9 stimulation were not observed. Notably, the soluble interferon response to viral stimulation by mononuclear cells was not diminished in pregnancy. CONCLUSIONS: Our data provide insight into the differential responsiveness of pregnancy-derived monocytes to ssRNA and dsRNA, mainly driven by TLR8 and membrane-bound TLR3, which may help to explain the increased susceptibility of pregnant women to adverse outcomes resulting from viral infection as observed during recent and historic pandemics.

Pregnancy tailors endotoxin-induced monocyte and neutrophil responses in the maternal circulation.

OBJECTIVE: To comprehensively characterize monocyte and neutrophil responses to E. coli and its product [lipopolysaccharide (LPS) or endotoxin] in vitro during pregnancy. MATERIAL OR SUBJECTS: Peripheral blood was collected from pregnant women during the third trimester (n = 20) and from non-pregnant women (n = 20). METHODS: The number, phagocytic activity, and reactive oxygen species (ROS) production of peripheral monocytes and neutrophils were investigated using flow cytometry. The phenotypes of peripheral monocytes and neutrophils after acute or chronic LPS stimulation were also determined using flow cytometry. Cytokine profiles were quantified for LPS-stimulated peripheral blood mononuclear cells (PBMCs) and a whole blood TruCulture® system using a multiplex immunoassay. RESULTS: Increased number, phagocytic activity, and ROS production capacity of monocytes and neutrophils were found in pregnant compared to non-pregnant women. Additionally, specific subsets of pro-inflammatory monocytes (IL-6+CD14+ or MIP-1α+CD14+ cells) and neutrophils (IL-1ß+CD15+ or MIP-1ß+CD15+ cells) were increased in pregnant women in response to acute LPS stimulation. Moreover, distinct subsets of intermediate-activated monocytes expressing CD142, IL-6, and IL-1RA were increased in pregnant women upon chronic LPS stimulation. Last, pregnant women displayed a different cytokine profile than non-pregnant women in LPS-stimulated PBMCs and in whole blood. CONCLUSIONS: Pregnancy tailors the immune responses of circulating monocytes and neutrophils to endotoxin, a Gram-negative bacterial product.

The Role of Hsp70 in the Regulation of Autophagy in Gametogenesis, Pregnancy, and Parturition.

Induction of the 70 kDa heat shock protein (hsp70) and autophagy are two major mechanisms that promote cell homeostasis during the rapid cell growth and differentiation characteristic of reproduction. Hsp70 insures proper assembly, conformation, and intracellular transport of nascent proteins. Autophagy removes from the cytoplasm proteins, other macromolecules, and organelles that are no longer functional or needed and recycles their components for synthesis of new products under nutritionally limiting conditions. Hsp70 inhibits autophagy and so a proper balance between these two processes is essential for optimal germ cell production and survival and pregnancy progression. A marked inhibition in autophagy and a concomitant increase in hsp70 at term is a trigger for parturition. Excessive external or endogenous stress that induces a high level of hsp70 production can lead to a non-physiological inhibition of autophagy, resulting in altered spermatogenesis, premature ovarian failure, and complications of pregnancy including preeclampsia, intrauterine growth restriction, and preterm birth.

Prevalence of lymph node metastasis and prognostic significance of lymphadenectomy in apparent early-stage malignant ovarian sex cord-stromal tumors.

OBJECTIVE: The aim of this retrospective population-based study was to investigate the prevalence of lymph node metastasis in patients with apparent early stage malignant sex cord-stromal tumors (SCSTs) and the effect of regional lymph node sampling/lymphadenectomy (LND) on their survival. METHODS: A cohort of patients diagnosed with malignant SCSTs between 1988 and 2012 was drawn from the National Cancer Institute's Surveillance, Epidemiology, and End Results database. Overall and Cancer Specific Survival, stratified by performance of LND, were calculated following generation of Kaplan-Meier curves. Comparisons were made using the log-rank and Breslow tests. A multivariate Cox proportional analysis was performed to determine the effect of LND on overall mortality. RESULTS: A total of 1156 patients with SCST met the inclusion criteria; 1000 (86.5%) and 156 (13.5%) patients had apparent stage I and II disease, respectively. LND was performed in 572 (49.5%) patients. Lymph node metastases were pathologically confirmed in 19 patients (3.3%). Five-year cancer specific survival (CSS) was similar, 92.7% and 94.7%, for patients who did or did not undergo LND, respectively. According to multivariate analysis overall mortality did not differ between the two groups after controlling for age, histology and apparent stage. CONCLUSIONS: Regional lymphatic mode metastasis in patients with apparent early stage SCSTs is uncommon and lymphadenectomy did not confer a survival benefit in this cohort.

Epidemiology of Second Primary Tumors in Women With Ovarian Cancer.

OBJECTIVE: The last large study of second primary tumors (SPTs) in women with ovarian cancer was published in 1996, prior to major changes in the differential diagnosis and treatment. The present study reports on the incidence of SPTs in a contemporary cohort of patients with a diagnosis of ovarian cancer. METHODS: Ovarian cancer patients with a diagnosis of an ovarian malignancy between 1992 and 2012 were identified and characterized from 13 registries of the Surveillance, Epidemiology, and End Results database. RESULTS: Of 41,073 women with a diagnosis of an ovarian malignancy between 1992 and 2012, 1831 (4.5%) developed a microscopically confirmed SPT. There was no significant difference in the risk of developing an SPT at all sites between women with an ovarian cancer and the general population. There was an elevated risk of site-specific SPTs of the small intestine, vagina, thyroid gland, and acute nonlymphocytic leukemia in ovarian cancer patients compared with the general Surveillance, Epidemiology, and End Results population. Conversely, the risk of lung and non-Hodgkin lymphoma was significantly decreased in women with ovarian cancer. An elevated risk of SPTs was observed in women with mucinous, endometrioid, and germ cell tumors. White women had an overall decreased risk of developing a second primary solid tumor, whereas American Indian and Asian/Pacific Islander women had an overall increased risk of an SPT at any site. CONCLUSIONS: The incidence of SPTs in women with ovarian cancer was not significantly different as compared with the general population. However, divergent rates of SPTs in relation to histology, latency, age, and race were observed.

Ability of cervical length to predict spontaneous preterm delivery in twin pregnancies using the receiver-operating characteristic curve analysis and an a priori cut-off value.

In this retrospective study based on cervical length (CL) measurements between 20 and 24 + 6 weeks, we examined the ability of CL to predict spontaneous preterm birth (SPTB) in 222 twin pregnancies using the receiver-operating curve (ROC) analysis and an a priori cut-off. CL predicted SPTB before 34 weeks. Using the ROC the selected cut-off was 37.5 mm. Positive predictive value (PPV) and negative predictive value (NPV) regarding SPTB before 34 weeks for 37.5 mm were 15.7% and 5.3% respectively. Using the 5th percentile, PPV and NPV regarding SPTB before 34 weeks for 24 mm were 41.7% and 91.4%, respectively. The 5th centile of CL measurements should be employed in clinical practice. CL measurement is an adequate screening tool for SPTB since it has a high NPV. Studies on CL measurement and SPTB should explain which methodology they adopted to obtain a cut-off value and the rationale of their choice.

Malignant Brenner tumors of the ovary; a population-based analysis.

OBJECTIVE: Malignant Brenner Tumor (MBT) is a tumor with an extremely low incidence that morphologically resembles to urothelium. Given the paucity of evidence on the epidemiology and prognosis of MBT, the aim of this retrospective population-based study was to elucidate the demographic and clinico-pathological characteristics of patients with ovarian MBT. METHODS: A cohort of patients diagnosed between 1988 and 2012 was drawn from the National Cancer Institute Surveillance and Epidemiology End Results database. For surgically treated patients, Observed and Disease Specific Survival were calculated following generation of Kaplan-Meier curves. Comparisons were made using the log-rank test. RESULTS: A total of 207 patients were identified. Median patient age was 65years and the majority presented with unilateral, high grade tumors with a median size of 10cm. Stage I, II, III and IV disease was noted for 55.4%, 14.4%, 18%, and 12.2% of patients respectively. Only 5.1% had positive lymph nodes for metastatic disease. Five-year disease-specific survival (DSS) of patients with tumors confined to the ovary was 94.5% compared to 51.3% for those with extra-ovarian spread (p<0.001). Lymphadenectomy was not associated with an improved DSS (p=0.2). CONCLUSIONS: MBTs are typically unilateral high grade tumors localized to the ovary. Regional lymphatic spread is uncommon and lymphadenectomy does not confer any improvement on survival. Patients with tumors confined to the ovary have an excellent prognosis while extra-ovarian spread is associated with a poor outcome.

Epidemiology and outcomes of squamous ovarian carcinoma; a population-based study.

OBJECTIVE: Squamous ovarian carcinoma (SOC) is a rare tumor. Scarcity of information about the epidemiology and prognosis of SOC hinders attempts at optimal patient management. This retrospective study of a large cohort details the clinicopathological and demographic characteristics and prognosis of women with SOC. METHODS: A cohort of patients drawn from the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database who were diagnosed with SOC between 1988 and 2012 were analyzed. Observed and disease-specific survival was estimated by Kaplan-Meier plots in women who underwent surgery as part of their cancer-related treatment. A Cox hazard regression analysis was performed to determine independent predictors of cancer-specific survival in patients with SOC. RESULTS: We identified 341 patients with SOC with a median age at diagnosis of 55 years. Stage I, II, III and IV tumors were noted in 34%, 15%, 20.5% and 24.9% of patients, respectively. Five-year cancer-specific survival was 86% for stage I, 54.3% for stage II, 36.3% for stage III and 2.8% for stage IV disease patients. Observed and cancer-specific survival was better for patients that underwent lymphadenectomy (p=0.031). Postoperative radiotherapy was not associated with improved survival. In a multivariate analysis, independent predictors of improved cancer-specific survival were younger age, lower disease stage and lymphadenectomy. CONCLUSIONS: SOC is typically a unilateral malignancy with a tendency toward loco-regional spread. Stage I patients have a relatively high survival rate; however, the prognosis is poor for women with abdominal or distant spread. Lymphadenectomy, but not postoperative radiotherapy, is associated with improved survival.

Prognostic Significance of Transitional Cell Carcinoma-Like Morphology of High-Grade Serous Ovarian Carcinoma: A Comparative Study.

OBJECTIVES: This was a retrospective population-based study investigating the demographic characteristics, clinical characteristics, and prognosis of patients with ovarian high-grade serous carcinoma displaying transitional cell carcinoma-like (TC-like) morphological features. MATERIALS AND METHODS: A cohort of patients diagnosed with ovarian high-grade serous carcinoma from 1988 to 2012 was drawn from the National Cancer Institute's Surveillance Epidemiology and End Results Database. Patients with transitional cell histology were included in the study group, whereas patients with other serous tumors served as controls. Demographic and clinical characteristics between the study and the control groups were compared using χ test. For surgically treated patients, survival was estimated by generation of Kaplan-Meier curves. Multivariate analysis was performed using the Cox regression method. RESULTS: A total of 29,716 patients met the inclusion criteria. From these, 264 patients (0.9%) were included in the TC-variant group, whereas 29,452 (99.1%) composed the control group. Patients with TC-variant tumors were younger and more likely to present with larger, unilateral tumors at an early disease stage. Surgically treated patients with advanced stage had a median disease-specific survival of 50 months compared with 40 months in the control group (P = 0.013). In that group, multivariate analysis confirmed that TC-like morphological features were an independent predictor of survival. CONCLUSIONS: High-grade serous carcinoma with TC-like morphological features was associated with unique demographic and clinical characteristics. For patients with advanced stage-disease, the presence of TC-like morphological features was associated with a superior survival.

Inhibition of autophagy in peripheral blood mononuclear cells by vaginal fluid from women with a malignant adnexal mass.

Inhibition of autophagy is a characteristic of ovarian cancer. We determined whether inhibition of autophagy by vaginal fluid could provide a non-invasive test for cancer risk stratification in women presenting with an adnexal mass. Vaginal fluid supernatants from 90 women undergoing evaluation for a suspicious adnexal mass were incubated with peripheral blood mononuclear cells (PBMCs) obtained from healthy women under conditions that induce autophagy. Rapamycin, an autophagy inducer, was added to some cultures. After 48 hr the cells were collected, lysed and assayed by ELISA for intracellular p62 concentration. p62 is a cytoplasmic protein that is consumed during autophagy induction. Its concentration is inversely proportional to the extent of autophagy induction. Clinical information including pathological diagnoses was obtained after completion of laboratory studies. Mean p62 levels were 9.4 ng/ml in the 21 women with a subsequent malignant diagnosis, 4.5 ng/ml in the eight women with a borderline tumor diagnosis and 3.6 ng/ml in the 61 women with benign disease (p < 0.0001, malignant vs. others). When rapamycin was added to the vaginal fluid-PBMC co-incubation, p62 levels in samples from women with a malignant diagnosis decreased to 3.3 ng/ml, a level comparable to what was observed with the nonmalignant samples. Vaginal fluid inhibition of autophagy can differentiate between women with malignant and benign adnexal masses.

Association of in vitro fertilization outcome with circulating insulin-like growth factor components prior to cycle initiation.

OBJECTIVE: Components of the insulin-like growth factor (IGF) system enhance in vitro embryo quality and implantation rates in both animal models and human in vitro fertilization (IVF). We evaluated whether differences in serum levels of these components in women prior to initiation of an IVF cycle would be predictive of subsequent outcome. STUDY DESIGN: In this retrospective study sera from women obtained at day 2 of their IVF cycle (at baseline before stimulation) were assayed for IGF-I, IGF-II, and IGF binding protein (BP)-1 by enzyme-linked immunosorbent assay. Samples from 54 women with a live birth, 38 with a transient biochemical pregnancy, 45 with a spontaneous abortion, 54 who did not become pregnant, and 35 who had an ectopic pregnancy were available for analysis. Associations between the assays and outcome were evaluated by the Kruskal-Wallis test and receiver operating characteristic analysis. RESULTS: There were no differences in the number of oocytes retrieved, oocyte quality, fertilization rates, or embryo grade between groups. Median concentrations of IGF-I were elevated in women with a live birth (29.1 ng/mL) as compared to women with a biochemical pregnancy (25.6 ng/mL), with spontaneous abortion (21.2 ng/mL), who were not pregnant (18.7 pg/mL), or who had an ectopic pregnancy (4.2 pg/mL) (P < .001). Conversely, median levels of IGF-II were reduced in women with a live birth (294.5 ng/mL) as opposed to 357.5, 393.6, 407.2, and 426.9 ng/mL in women with a biochemical pregnancy, with ectopic pregnancy, with spontaneous abortion, or who were not pregnant, respectively (P < .001). Median IGFBP-1 concentrations were markedly elevated in women with a live birth (23.6 ng/mL) compared to 18.3, 14.1, 13.8, and 9.5 ng/mL in women with a biochemical pregnancy, with spontaneous abortion, who were not pregnant, or with an ectopic pregnancy (P < .001). The combination of IGF-I and IGFBP-1 best predicted the occurrence of a live birth with an area under the curve of 0.892. CONCLUSION: Maternal serum levels of IGF-I, IGF-II, and IGFBP-1 prior to initiation of an IVF cycle are correlated with the likelihood of a live birth. Alterations in maternal IGF system components may influence oocyte quality or the success of early postfertilization events and embryo implantation.

Rate of second primary tumors following diagnosed choriocarcinoma: a SEER analysis (1973-2010).

OBJECTIVE: Approximately 1 in 6 of new cancers has been reported to represent a second primary tumor (SPT). Choriocarcinomas (CCs) are of interest in regard to the rate of SPTs because of the potential exposure to carcinogenic therapy and reports of the benefits of its high human gonadotropin (hCG) levels on cancer incidence. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with gestational CC who subsequently developed a SPT. This is a retrospective study, following a cohort of patients during the period 1973-2010. RESULTS: We found 818 patients with primary gestational CC. Nineteen patients had a SPT after the CC. Occurrence of several types of cancer resulted significantly higher when compared to the incidence rate in the general population. In particular the highest incidence rate ratios (IRRs) were registered for acute myeloid leukemia (AML) (6.3) and thyroid cancer (2.6). The expected rate of lung, breast, colorectal and uterine corpus cancers instead resulted lower than the rate in the general population. Regarding the IRR in the population under 50 years of age, the higher IRRs were related to AML (20) and non-Hodgkin lymphoma (NHL) (5). CONCLUSION: The association of thyroid cancer and CC has not been described previously. Increases in hematological cancer following CC lend further support to the established data. The decrease in breast and colon cancers in all age groups supports past data and decreases in uterine and lung cancers are new observations meriting further study.

Ethnic disparity in amniotic fluid levels of hyaluronan, histone H2B and superoxide dismutase in spontaneous preterm birth.

AIMS: To document racial disparity in an immune modulator, hyaluronan (HA), an antimicrobial, histone H2B (H2B), and an antioxidant, superoxide dismutase (SOD) in amniotic fluid (AF) from African-American (AA) and Caucasian (C) subjects with spontaneous preterm birth (PTB). METHODS: In a case (PTB) control (term) study, AF samples were analyzed for HA, H2B and SOD by ELISA. Differences in analyte concentrations between races were documented and a secondary analysis based on histologic chorioamnionitis (HC) was also performed. RESULTS: No differences in the median HA, H2B and SOD were seen between cases and controls. AA cases had lower HA but higher H2B and SOD than controls. Analyte concentrations were not different between C cases and controls. AA samples at term had lower H2B and SOD compared to C samples at term. Cases with HC showed higher H2B and SOD. CONCLUSION: We report ethnic disparity in AF antimicrobial, immune mediator and antioxidant factors. Dysregulated AF production of HA, H2B and SOD was associated with PTB in AA, not in C, suggesting an overwhelming inflammatory response in AA PTB, whereas inflammation is likely a secondary phenomenon in C PTB.

Soluble suppression of tumorigenicity-2 in pregnancy with a small-for-gestational-age fetus and with preeclampsia.

OBJECTIVE: Preeclampsia and fetal growth disorders are pregnancy-specific conditions that share common pathophysiological mechanisms. Yet, why some patients develop preeclampsia while others experience fetal growth restriction, or a combination of both clinical presentations, is unknown. We propose that the difference in severity of the maternal inflammatory response can contribute to the clinical phenotypes of preeclampsia vs. small for gestational age (SGA). To assess this hypothesis, we measured maternal plasma concentrations of the soluble isoform of suppression of tumorigenicity-2 (sST2), a member of the interleukin-1 receptor family that buffers proinflammatory responses. Previous reports showed that serum sST2 concentrations rise in the presence of intravascular inflammation and Th1-type immune responses and are significantly higher in patients with preeclampsia compared to those with normal pregnancy. The behavior of sST2 in pregnancies complicated by SGA has not been reported. This study was conducted to compare sST2 plasma concentrations in normal pregnancies, in those with preeclampsia, and in those with an SGA fetus. METHODS: This retrospective cross-sectional study included women with an SGA fetus (n = 52), women with preeclampsia (n = 106), and those with normal pregnancy (n = 131). Maternal plasma concentrations of sST2 were determined by enzyme-linked immunosorbent assay. Doppler velocimetry of the uterine and umbilical arteries was available in a subset of patients with SGA (42 patients and 43 patients, respectively). RESULTS: (1) Women with an SGA fetus had a significantly higher median plasma concentration of sST2 than normal pregnant women (p = .008); (2) women with preeclampsia had a significantly higher median plasma concentration of sST2 than those with normal pregnancy (p < .001) and those with an SGA fetus (p < .001); (3) patients with SGA and abnormal uterine artery Doppler velocimetry had a higher median plasma concentration of sST2 than controls (p < .01) and those with SGA and normal uterine artery Doppler velocimetry (p = .02); (4) there was no significant difference in the median plasma sST2 concentration between patients with SGA who had normal uterine artery Doppler velocimetry and controls (p = .4); (5) among patients with SGA, those with abnormal and those with normal umbilical artery Doppler velocimetry had higher median plasma sST2 concentrations than controls (p = .001 and p = .02, respectively); and (6) there was no significant difference in the median plasma sST2 concentrations between patients with SGA who did and those who did not have abnormal umbilical artery Doppler velocimetry (p = .06). CONCLUSIONS: Preeclampsia and disorders of fetal growth are conditions characterized by intravascular inflammation, as reflected by maternal plasma concentrations of sST2. The severity of intravascular inflammation is highest in patients with preeclampsia.

Host-microbiome interactions in distinct subsets of preterm labor and birth.

Preterm birth, the leading cause of perinatal morbidity, often follows premature labor, a syndrome whose prevention remains a challenge. To better understand the relationship between premature labor and host-microbiome interactions, we conducted a mechanistic investigation using three preterm birth models. We report that intra-amniotic delivery of LPS triggers inflammatory responses in the amniotic cavity and cervico-vaginal microenvironment, causing vaginal microbiome changes and signs of active labor. Intra-amniotic IL-1α delivery causes a moderate inflammatory response in the amniotic cavity but increasing inflammation in the cervico-vaginal space, leading to vaginal microbiome disruption and signs of active labor. Conversely, progesterone action blockade by RU-486 triggers local immune responses accompanying signs of active labor without altering the vaginal microbiome. Preterm labor facilitates ascension of cervico-vaginal bacteria into the amniotic cavity, regardless of stimulus. This study provides compelling mechanistic insights into the dynamic host-microbiome interactions within the cervico-vaginal microenvironment that accompany premature labor and birth.

A key role for NLRP3 signaling in preterm labor and birth driven by the alarmin S100B.

Preterm birth remains the leading cause of neonatal morbidity and mortality worldwide. A substantial number of spontaneous preterm births occur in the context of sterile intra-amniotic inflammation, a condition that has been mechanistically proven to be triggered by alarmins. However, sterile intra-amniotic inflammation still lacks treatment. The NLRP3 inflammasome has been implicated in sterile intra-amniotic inflammation; yet, its underlying mechanisms, as well as the maternal and fetal contributions to this signaling pathway, are unclear. Herein, by utilizing a translational and clinically relevant model of alarmin-induced preterm labor and birth in Nlrp3-/- mice, we investigated the role of NLRP3 signaling by using imaging and molecular biology approaches. Nlrp3 deficiency abrogated preterm birth and the resulting neonatal mortality induced by the alarmin S100B by impeding the premature activation of the common pathway of labor as well as by dampening intra-amniotic and fetal inflammation. Moreover, Nlrp3 deficiency altered leukocyte infiltration and functionality in the uterus and decidua. Last, embryo transfer revealed that maternal and fetal Nlrp3 signaling contribute to alarmin-induced preterm birth and neonatal mortality, further strengthening the concept that both individuals participate in the complex process of preterm parturition. These findings provide novel insights into sterile intra-amniotic inflammation, a common etiology of preterm labor and birth, suggesting that the adverse perinatal outcomes resulting from prematurity can be prevented by targeting NLRP3 signaling.

Thymic stromal lymphopoietin participates in the host response to intra-amniotic inflammation leading to preterm labor and birth.

The aim of this study was to establish the role of thymic stromal lymphopoietin (TSLP) in the intra-amniotic host response of women with spontaneous preterm labor (sPTL) and birth. Amniotic fluid and chorioamniotic membranes (CAM) were collected from women with sPTL who delivered at term (n = 30) or preterm without intra-amniotic inflammation (n = 34), with sterile intra-amniotic inflammation (SIAI, n = 27), or with intra-amniotic infection (IAI, n = 17). Amnion epithelial cells (AEC), Ureaplasma parvum, and Sneathia spp. were also utilized. The expression of TSLP, TSLPR, and IL-7Rα was evaluated in amniotic fluid or CAM by RT-qPCR and/or immunoassays. AEC co-cultured with Ureaplasma parvum or Sneathia spp. were evaluated for TSLP expression by immunofluorescence and/or RT-qPCR. Our data show that TSLP was elevated in amniotic fluid of women with SIAI or IAI and expressed by the CAM. TSLPR and IL-7Rα had detectable gene and protein expression in the CAM; yet, CRLF2 was specifically elevated with IAI. While TSLP localized to all layers of the CAM and increased with SIAI or IAI, TSLPR and IL-7Rα were minimal and became most apparent with IAI. Co-culture experiments indicated that Ureaplasma parvum and Sneathia spp. differentially upregulated TSLP expression in AEC. Together, these findings indicate that TSLP is a central component of the intra-amniotic host response during sPTL.

Blockade of IL-6R prevents preterm birth and adverse neonatal outcomes.

BACKGROUND: Preterm birth preceded by spontaneous preterm labour often occurs in the clinical setting of sterile intra-amniotic inflammation (SIAI), a condition that currently lacks treatment. METHODS: Proteomic and scRNA-seq human data were analysed to evaluate the role of IL-6 and IL-1α in SIAI. A C57BL/6 murine model of SIAI-induced preterm birth was developed by the ultrasound-guided intra-amniotic injection of IL-1α. The blockade of IL-6R by using an aIL-6R was tested as prenatal treatment for preterm birth and adverse neonatal outcomes. QUEST-MRI evaluated brain oxidative stress in utero. Targeted transcriptomic profiling assessed maternal, foetal, and neonatal inflammation. Neonatal biometrics and neurodevelopment were tested. The neonatal gut immune-microbiome was evaluated using metagenomic sequencing and immunophenotyping. FINDINGS: IL-6 plays a critical role in the human intra-amniotic inflammatory response, which is associated with elevated concentrations of the alarmin IL-1α. Intra-amniotic injection of IL-1α resembles SIAI, inducing preterm birth (7% vs. 50%, p = 0.03, Fisher's exact test) and neonatal mortality (18% vs. 56%, p = 0.02, Mann-Whitney U-test). QUEST-MRI revealed no foetal brain oxidative stress upon in utero IL-1α exposure (p > 0.05, mixed linear model). Prenatal treatment with aIL-6R abrogated IL-1α-induced preterm birth (50% vs. 7%, p = 0.03, Fisher's exact test) by dampening inflammatory processes associated with the common pathway of labour. Importantly, aIL-6R reduces neonatal mortality (56% vs. 22%, p = 0.03, Mann-Whitney U-test) by crossing from the mother to the amniotic cavity, dampening foetal organ inflammation and improving growth. Beneficial effects of prenatal IL-6R blockade carried over to neonatal life, improving survival, growth, neurodevelopment, and gut immune homeostasis. INTERPRETATION: IL-6R blockade can serve as a strategy to treat SIAI, preventing preterm birth and adverse neonatal outcomes. FUNDING: NICHD/NIH/DHHS, Contract HHSN275201300006C. WSU Perinatal Initiative in Maternal, Perinatal and Child Health.