Amniotic fluid heat shock protein 70 concentration in histologic chorioamnionitis, term and preterm parturition

Clinical chorioamnionitis at term: definition, pathogenesis, microbiology, diagnosis, and treatment

Clinical chorioamnionitis, the most common infection-related diagnosis in labor and delivery units, is an antecedent of puerperal infection and neonatal sepsis. The condition is suspected when intrapartum fever is associated with two other maternal and fetal signs of local or systemic inflammation (eg, maternal tachycardia, uterine tenderness, maternal leukocytosis, malodorous vaginal discharge or amniotic fluid, and fetal tachycardia). Clinical chorioamnionitis is a syndrome caused by intraamniotic infection, sterile intraamniotic inflammation (inflammation without bacteria), or systemic maternal inflammation induced by epidural analgesia. In cases of uncertainty, a definitive diagnosis can be made by analyzing amniotic fluid with methods to detect bacteria (Gram stain, culture, or microbial nucleic acid) and inflammation (white blood cell count, glucose concentration, interleukin-6, interleukin-8, matrix metalloproteinase-8). The most common microorganisms are Ureaplasma species, and polymicrobial infections occur in 70% of cases. The fetal attack rate is low, and the rate of positive neonatal blood cultures ranges between 0.2% and 4%. Intrapartum antibiotic administration is the standard treatment to reduce neonatal sepsis. Treatment with ampicillin and gentamicin have been recommended by professional societies, although other antibiotic regimens, eg, cephalosporins, have been used. Given the importance of Ureaplasma species as a cause of intraamniotic infection, consideration needs to be given to the administration of antimicrobial agents effective against these microorganisms such as azithromycin or clarithromycin. We have used the combination of ceftriaxone, clarithromycin, and metronidazole, which has been shown to eradicate intraamniotic infection with microbiologic studies. Routine testing of neonates born to affected mothers for genital mycoplasmas could improve the detection of neonatal sepsis. Clinical chorioamnionitis is associated with decreased uterine activity, failure to progress in labor, and postpartum hemorrhage; however, clinical chorioamnionitis by itself is not an indication for cesarean delivery. Oxytocin is often administered for labor augmentation, and it is prudent to have uterotonic agents at hand to manage postpartum hemorrhage. Infants born to mothers with clinical chorioamnionitis near term are at risk for early-onset neonatal sepsis and for long-term disability such as cerebral palsy. A frontier is the noninvasive assessment of amniotic fluid to diagnose intraamniotic inflammation with a transcervical amniotic fluid collector and a rapid bedside test for IL-8 for patients with ruptured membranes. This approach promises to improve diagnostic accuracy and to provide a basis for antimicrobial administration.

Complement Activation Fragments in Cervicovaginal Fluid Are Associated with Intra-Amniotic Infection/Inflammation and Spontaneous Preterm Birth in Women with Preterm Premature Rupture of Membranes

OBJECTIVE

 We sought to determine whether the levels of complement and other inflammatory and angiogenic mediators in cervicovaginal fluid (CVF) are independently associated with intra-amniotic infection and/or inflammation (IAI) and imminent spontaneous preterm birth (SPTB, £48 hours of sampling) in women with preterm premature rupture of membranes (PPROM).

STUDY DESIGN

 This was a retrospective study consisting of 85 singleton pregnant women with PPROM at 200/7 to 336/7 weeks. Amniotic fluid (AF) obtained via amniocentesis was cultured and assayed for interleukin-6. CVF samples collected at the time of amniocentesis were assayed for complement C3a, C4a, and C5a, HSP70 (heat shock protein 70), M-CSF (macrophage colony-stimulating factor), M-CSF-R (macrophage colony-stimulating factor-receptor), S100 A8, S100 A9, thrombospondin-2, VEGF (vascular endothelial growth factor-receptor), and VEGFR-1 (vascular endothelial growth factor-receptor 1) by enzyme-linked immunosorbent assay.

RESULTS

 Multivariate logistic regression analyses revealed that elevated CVF concentrations of complement C3a, 4a, and 5a were significantly associated with an increased risk of IAI and imminent SPTB, whereas those of M-CSF were associated with IAI, but not imminent SPTB (p = 0.063), after adjustment for baseline covariates (e.g., gestational age at sampling). However, univariate, and multivariate analyses showed that the CVF concentrations of angiogenic (thrombospondin-2, VEGF, and VEGFR-1) and inflammatory (HSP70, M-CSF-R, S100 A8, and S100 A9) proteins were not associated with either IAI or imminent SPTB.

CONCLUSION

 In women with PPROM, elevated CVF concentrations of complement C3a, C4a, and C5a are independently related to an increased risk of IAI and imminent SPTB. These findings suggest that complement activation in CVF is significantly involved in mechanisms underlying preterm birth and in the host response to IAI in the context of PPROM.

KEY POINTS

· Elevated CVF levels of C3a, 4a and 5a are associated with IAI and SPTB.. · CVF C3a, 4a and 5a have better predictability for SPTB, compared to AF WBC.. · Elevated CVF levels of M-CSF were associated with IAI, but not SPTB..

Urinary HSP70 improves diagnostic accuracy for urinary tract infection in children: UTILISE study

BACKGROUND

The accuracy of conventional urinalysis in diagnosing urinary tract infection (UTI) in children is limited, leading to unnecessary antibiotic exposure in a large fraction of patients. Urinary heat shock protein 70 (uHSP70) is a novel marker of acute urinary tract inflammation. We explored the added value of uHSP70 in discriminating UTI from other infections and conditions confused with UTI.

METHODS

A total of 802 children from 37 pediatric centers in seven countries participated in the study. Patients diagnosed with UTI (n = 191), non-UTI infections (n = 178), contaminated urine samples (n = 50), asymptomatic bacteriuria (n = 26), and healthy controls (n = 75) were enrolled. Urine and serum levels of HSP70 were measured at presentation in all patients and after resolution of the infection in patients with confirmed UTI.

RESULTS

Urinary (u)HSP70 was selectively elevated in children with UTI as compared to all other conditions (p < 0.0001). uHSP70 predicted UTI with 89% sensitivity and 82% specificity (AUC = 0.934). Among the 265 patients with suspected UTI, the uHSP70 > 48 ng/mL criterion identified the 172 children with subsequently confirmed UTI with 90% sensitivity and 82% specificity (AUC = 0.862), exceeding the individual diagnostic accuracy of leukocyturia, nitrite, and leukocyte esterase positivity. uHSP70 had completely normalized by the end of antibiotic therapy in the UTI patients. Serum HSP70 was not predictive.

CONCLUSIONS

Urine HSP70 is a novel non-invasive marker of UTI that improves the diagnostic accuracy of conventional urinalysis. We estimate that rapid urine HSP70 screening could spare empiric antibiotic administration in up to 80% of children with suspected UTI. A higher resolution version of the Graphical abstract is available as Supplementary information.

The amniotic fluid proteome changes with term labor and informs biomarker discovery in maternal plasma

The intra-uterine components of labor, namely, myometrial contractility, cervical ripening, and decidua/membrane activation, have been extensively characterized and involve a local pro-inflammatory milieu of cellular and soluble immune mediators. Targeted profiling has demonstrated that such processes extend to the intra-amniotic space, yet unbiased analyses of the proteome of human amniotic fluid during labor are lacking. Herein, we utilized an aptamer-based platform to characterize 1,310 amniotic fluid proteins and found that the proteome undergoes substantial changes with term labor (251 proteins with differential abundance, q < 0.1, and fold change > 1.25). Proteins with increased abundance in labor are enriched for immune and inflammatory processes, consistent with prior reports of labor-associated changes in the intra-uterine space. By integrating the amniotic fluid proteome with previously generated placental-derived single-cell RNA-seq data, we demonstrated the labor-driven upregulation of signatures corresponding to stromal-3 and decidual cells. We also determined that changes in amniotic fluid protein abundance are reflected in the maternal plasma proteome. Collectively, these findings provide novel insights into the amniotic fluid proteome in term labor and support its potential use as a source of biomarkers to distinguish between true and false labor by using maternal blood samples.

Elevated human placental heat shock protein 5 is associated with spontaneous preterm birth

BACKGROUND

Specific heat shock proteins are associated with pregnancy complications, including spontaneous preterm birth (SPTB). Placental proteomics and whole exome sequencing recently suggested an association between heat shock protein HSPA5 and uncomplicated SPTB. In the present study, we investigated the localization of and possible roles for HSPA5 in SPTB.

METHODS

Western blot was performed to validate the result from the previously published proteomic analysis. We used qPCR to assess mRNA expression of genes and immunohistochemistry and immunoelectron microscopy to examine localization of HSPA5 in placental tissue. We silenced the HSPA5 gene in the HTR8/SVneo human trophoblast cell line to investigate possible functions of HSPA5.

RESULTS

HSPA5 was upregulated in placentas from SPTBs compared to spontaneous term births. We did not observe upregulation of HSPA5 mRNA in placental samples. The protein was localized in placental trophoblast in both spontaneous preterm and term placentas. Gene silencing of HSPA5 in human trophoblast cell culture affected the inflammatory response and decreased the expression of several proinflammatory genes.

CONCLUSIONS

We suggest that upregulation of HSPA5 in the placenta is associated with spontaneous preterm labor. HSPA5 may promote the inflammatory response and alter the anti-inflammatory state of the placenta which could eventually lead to premature labor.

IMPACT

We validated upregulation of HSPA5 in placentas from spontaneous preterm birth. HSPA5 was not upregulated at transcriptional level which suggests that it may be regulated post-translationally. Silencing HSPA5 in a human trophoblast-derived cell line suggested that HSPA5 promotes expression of proinflammatory cytokines. The emerging inflammation could lead to spontaneous preterm labor. Identifying inflammatory pathways and factors associated with spontaneous preterm birth increases knowledge of the molecular mechanisms of premature labor. This could provide cues to predict imminent premature labor and lead to information about how to safely maintain pregnancies.

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

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

Clarithromycin prevents preterm birth and neonatal mortality by dampening alarmin-induced maternal–fetal inflammation in mice

Background

One of every four preterm neonates is born to a woman with sterile intra-amniotic inflammation (inflammatory process induced by alarmins); yet, this clinical condition still lacks treatment. Herein, we utilized an established murine model of sterile intra-amniotic inflammation induced by the alarmin high-mobility group box-1 (HMGB1) to evaluate whether treatment with clarithromycin prevents preterm birth and adverse neonatal outcomes by dampening maternal and fetal inflammatory responses.

Methods

Pregnant mice were intra-amniotically injected with HMGB1 under ultrasound guidance and treated with clarithromycin or vehicle control, and pregnancy and neonatal outcomes were recorded (n = 15 dams each). Additionally, amniotic fluid, placenta, uterine decidua, cervix, and fetal tissues were collected prior to preterm birth for determination of the inflammatory status (n = 7–8 dams each).

Results

Clarithromycin extended the gestational length, reduced the rate of preterm birth, and improved neonatal mortality induced by HMGB1. Clarithromycin prevented preterm birth by interfering with the common cascade of parturition as evidenced by dysregulated expression of contractility-associated proteins and inflammatory mediators in the intra-uterine tissues. Notably, clarithromycin improved neonatal survival by dampening inflammation in the placenta as well as in the fetal lung, intestine, liver, and spleen.

Conclusions

Clarithromycin prevents preterm birth and improves neonatal survival in an animal model of sterile intra-amniotic inflammation, demonstrating the potential utility of this macrolide for treating women with this clinical condition, which currently lacks a therapeutic intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04764-2.

Proteomic identification of novel plasma biomarkers associated with spontaneous preterm birth in women with preterm labor without infection/inflammation

Objective

We sought to identify plasma biomarkers associated with spontaneous preterm birth (SPTB, delivery within 21 days of sampling) in women with preterm labor (PTL) without intra-amniotic infection/inflammation (IAI) using label-free quantitative proteomic analysis, as well as to elucidate specific protein pathways involved in these cases.

Methods

This was a retrospective cohort study comprising 104 singleton pregnant women with PTL (24–32 weeks) who underwent amniocentesis and demonstrated no evidence of IAI. Analysis of pooled plasma samples collected from SPTB cases and term birth (TB) controls (n = 10 for each group) was performed using label-free quantitative mass spectrometry for proteome profiling in a nested case-control study design. Eight candidate proteins of interest were validated by ELISA-based assay and a clot-based assay in the total cohort.

Results

Ninety-one proteins were differentially expressed (P < 0.05) in plasma samples obtained from SPTB cases, of which 53 (58.2%) were upregulated and 38 (41.8%) were downregulated when compared to TD controls. A validation study confirmed that plasma from women who delivered spontaneously within 21 days of sampling contained significantly higher levels of coagulation factor Ⅴ and lower levels of S100 calcium binding protein A9 (S100A9), especially the former which was independent of baseline variables. The top-ranked pathways related to the 91 differentially expressed proteins were liver-X-receptor/retinoid X receptor (RXR) activation, acute phase response signaling, farnesoid X receptor/RXR activation, coagulation system, and complement system.

Conclusions

Proteomic analyses in this study identified potential novel biomarkers (i.e., coagulation factor V and S100A9) and potential protein pathways in plasma associated with SPTB in the absence of IAI in women with PTL. The present findings provide novel insights into the molecular pathogenesis and therapeutic targets specific for idiopathic SPTB.

Pathophysiological Implication of Pattern Recognition Receptors in Fetal Membranes Rupture: RAGE and NLRP Inflammasome

Preterm prelabor ruptures of fetal membranes (pPROM) are a pregnancy complication responsible for 30% of all preterm births. This pathology currently appears more as a consequence of early and uncontrolled process runaway activation, which is usually implicated in the physiologic rupture at term: inflammation. This phenomenon can be septic but also sterile. In this latter case, the inflammation depends on some specific molecules called “alarmins” or “damage-associated molecular patterns” (DAMPs) that are recognized by pattern recognition receptors (PRRs), leading to a microbial-free inflammatory response. Recent data clarify how this activation works and which receptor translates this inflammatory signaling into fetal membranes (FM) to manage a successful rupture after 37 weeks of gestation. In this context, this review focused on two PRRs: the receptor for advanced glycation end-products (RAGE) and the NLRP7 inflammasome.

The alarmin interleukin-1α causes preterm birth through the NLRP3 inflammasome

Sterile intra-amniotic inflammation is a clinical condition frequently observed in women with preterm labor and birth, the leading cause of neonatal morbidity and mortality worldwide. Growing evidence suggests that alarmins found in amniotic fluid, such as interleukin (IL)-1α, are central initiators of sterile intra-amniotic inflammation. However, the causal link between elevated intra-amniotic concentrations of IL-1α and preterm birth has yet to be established. Herein, using an animal model of ultrasound-guided intra-amniotic injection of IL-1α, we show that elevated concentrations of IL-1α cause preterm birth and neonatal mortality. Additionally, using immunoblotting techniques and a specific immunoassay, we report that the intra-amniotic administration of IL-1α induces activation of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in the fetal membranes, but not in the decidua, as evidenced by a concomitant increase in the protein levels of NLRP3, active caspase-1, and IL-1β. Lastly, using Nlrp3-/- mice, we demonstrate that the deficiency of this inflammasome sensor molecule reduces the rates of preterm birth and neonatal mortality caused by the intra-amniotic injection of IL-1α. Collectively, these results demonstrate a causal link between elevated IL-1α concentrations in the amniotic cavity and preterm birth as well as adverse neonatal outcomes, a pathological process that is mediated by the NLRP3 inflammasome. These findings shed light on the mechanisms underlying sterile intra-amniotic inflammation and provide further evidence that this clinical condition can potentially be treated by targeting the NLRP3 inflammasome.

Integrative genetic, genomic and transcriptomic analysis of heat shock protein and nuclear hormone receptor gene associations with spontaneous preterm birth

Heat shock proteins are involved in the response to stress including activation of the immune response. Elevated circulating heat shock proteins are associated with spontaneous preterm birth (SPTB). Intracellular heat shock proteins act as multifunctional molecular chaperones that regulate activity of nuclear hormone receptors. Since SPTB has a significant genetic predisposition, our objective was to identify genetic and transcriptomic evidence of heat shock proteins and nuclear hormone receptors that may affect risk for SPTB. We investigated all 97 genes encoding members of the heat shock protein families and all 49 genes encoding nuclear hormone receptors for their potential role in SPTB susceptibility. We used multiple genetic and genomic datasets including genome-wide association studies (GWASs), whole-exome sequencing (WES), and placental transcriptomics to identify SPTB predisposing factors from the mother, infant, and placenta. There were multiple associations of heat shock protein and nuclear hormone receptor genes with SPTB. Several orthogonal datasets supported roles for SEC63, HSPA1L, SACS, RORA, and AR in susceptibility to SPTB. We propose that suppression of specific heat shock proteins promotes maintenance of pregnancy, whereas activation of specific heat shock protein mediated signaling may disturb maternal–fetal tolerance and promote labor.

The amniotic fluid cell-free transcriptome in spontaneous preterm labor

The amniotic fluid (AF) cell-free RNA was shown to reflect physiological and pathological processes in pregnancy, but its value in the prediction of spontaneous preterm delivery is unknown. Herein we profiled cell-free RNA in AF samples collected from women who underwent transabdominal amniocentesis after an episode of spontaneous preterm labor and subsequently delivered within 24 h (n = 10) or later (n = 28) in gestation. Expression of known placental single-cell RNA-Seq signatures was quantified in AF cell-free RNA and compared between the groups. Random forest models were applied to predict time-to-delivery after amniocentesis. There were 2385 genes differentially expressed in AF samples of women who delivered within 24 h of amniocentesis compared to gestational age-matched samples from women who delivered after 24 h of amniocentesis. Genes with cell-free RNA changes were associated with immune and inflammatory processes related to the onset of labor, and the expression of placental single-cell RNA-Seq signatures of immune cells was increased with imminent delivery. AF transcriptomic prediction models captured these effects and predicted delivery within 24 h of amniocentesis (AUROC = 0.81). These results may inform the development of biomarkers for spontaneous preterm birth.

Temperature variation and preterm birth among live singleton deliveries in Shenzhen, China: A time-to-event analysis

OBJECTIVE

Ambient temperature extremes due to heat exposure was an established risk factor for preterm birth (<37 gestational weeks). However, there is insufficient epidemiological evidence on the effects of temperature variation(TV), although TV is also associated with heat exposure and can influence human health risk. This study aimed to investigate the relationship between inter- and intraday TV and preterm birth (PTB).

METHOD

A total of 1,388,994 live singleton births were collected from January 2003 to December 2012, from the Shenzhen Birth registry system. Daily temperature range (DTR) was defined as the difference between the highest and lowest recorded daily temperature. Intraday TV was defined as the maximum daily diurnal temperature range in a given week (Max-DTR). Inter-day TV was defined as the maximum increase or decrease in daily mean temperature between days t and t-1in a given week; either an increase (Temp-inc) or a decrease (Temp-dec). We used Cox proportional hazards models to estimate TV-related PTB risks during the first trimester, the second trimester, and in late pregnancy.

RESULTS

The maximum values for DTR, Temp-inc, and Temp-dec were 17 °C, 8 °C and 11 °C, respectively. The greatest TV-related PTB risk occurred in the second trimester, with 5.8% (95%CI: 3.3%, 8.3%), 23.7% (95%CI: 19.6%, 27.9%), and 4.4% (95%CI: 1.8%, 7.1%) differences per 1 °C increase in Max-DTR, Temp-inc, and Temp-dec, respectively. Greater TV was associated with elevated PTB risk during the warm season. The association between TV and PTB was modified by seasons, maternal education and chronic conditions.

CONCLUSIONS

Sharp TV is a likely risk factor for PTB. Policy makers and clinicians should recognize the potential role of TV in the etiology of PTB so that interventions can be designed to protect pregnant women and their fetuses against extreme temperatures.

Inducible heat shock protein A1A (HSPA1A) is markedly expressed in rat myometrium by labour and secreted via myometrial cell-derived extracellular vesicles

The myometrium goes through physiological, cellular and molecular alterations during gestation that necessitate effective cellular proteostasis. Inducible heat shock protein A1A (HSPA1A) is a member of the 70-kDa heat shock protein A (HSPA) family, which acts as a chaperone to regulate proteostasis; however, HSPA1A also participates as a cytokine in inflammatory regulation, leading to its designation as a chaperokine. This study examined the spatiotemporal expression of HSPA1A protein in the rat myometrium throughout gestation and assessed whether it is secreted as cargo of myometrial cell-derived extracellular vesicles (EVs). Immunoblot analysis demonstrated that HSPA1A expression was markedly elevated during late pregnancy and labour and increased by uterine distension. Myometrial HSPA1A expression insitu increased in myocytes of longitudinal and circular muscle layers from Day 19 through to postpartum, specifically in the cytoplasm and nuclei of myocytes from both muscle layers, but frequently detectable just outside myocyte membranes. Scanning electron microscopy examination of samples isolated from hTERT-HM cell-conditioned culture medium, using EV isolation spin columns, confirmed the presence of EVs. EV lysates contained HSPA8, HSPA1A and the EV markers apoptosis-linked gene 2-interacting protein X (Alix), the tetraspanin cluster of differentiation 63 (CD63), tumour susceptibility gene 101 (TSG101) and HSP90, but not the endoplasmic reticulum protein calnexin. These results indicate that HSPA1A may act as a chaperokine in the myometrium during pregnancy.

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.

Human β-defensin-3 participates in intra-amniotic host defense in women with labor at term, spontaneous preterm labor and intact membranes, and preterm prelabor rupture of membranes

Objective: Human β-defensin-3 (HBD-3) has a broad spectrum of antimicrobial activity, and activity and, therefore, plays a central role in host defense mechanisms against infection. Herein, we determined whether HBD-3 was a physiological constituent of amniotic fluid during midtrimester and at term and whether the concentration of this defensin was increased in amniotic fluid of women with spontaneous preterm labor and intact membranes and those with preterm prelabor rupture of membranes (pPROM) with intra-amniotic inflammation or intra-amniotic infection.Methods: Amniotic fluid was collected from 219 women in the following groups: (1) midtrimester who delivered at term (n = 35); (2) with or without spontaneous labor at term (n = 50); (3) spontaneous preterm labor with intact membranes who delivered at term (n = 29); (4) spontaneous preterm labor with intact membranes who delivered preterm with or without intra-amniotic inflammation or intra-amniotic infection (n = 69); and (5) pPROM with or without intra-amniotic infection (n = 36). Amniotic fluid HBD-3 concentrations were determined using a sensitive and specific ELISA kit.Results: (1) HBD-3 is a physiological constituent of amniotic fluid; (2) the amniotic fluid concentration of HBD-3 did not change with gestational age (midtrimester versus term not in labor); (3) amniotic fluid concentrations of HBD-3 were higher in women with spontaneous labor at term than in those without labor; (4) in the absence of intra-amniotic inflammation, amniotic fluid concentrations of HBD-3 were similar between women with spontaneous preterm labor who delivered preterm and those who delivered at term; (5) among patients with spontaneous preterm labor who delivered preterm, amniotic fluid concentrations of HBD-3 were greater in women with intra-amniotic infection than in those without this clinical condition; (6) among patients with spontaneous preterm labor, amniotic fluid concentrations of HBD-3 were higher in women with intra-amniotic inflammation or intra-amniotic infection who delivered preterm than in those without these clinical conditions who delivered at term; and (7) women with pPROM and intra-amniotic infection had higher median amniotic fluid concentrations of HBD-3 than those without this clinical condition.Conclusion: Human β-defensin-3 is a physiological constituent of amniotic fluid and increases during the process of labor at term. Amniotic fluid concentrations of HBD-3 were increased in women with spontaneous preterm labor with intact membranes or pPROM with intra-amniotic inflammation or intra-amniotic infection, indicating that this defensin participates in the host defense mechanisms in the amniotic cavity against microorganisms or danger signals. These findings provide insight into the soluble host defense mechanisms against intra-amniotic inflammation and intra-amniotic infection.

Addition of exogenous proteins detected in oviductal secretions to in vitro culture medium does not improve the efficiency of in vitro fertilization in pigs

This work was designed to study whether HSP70-1A, HSP90α, ezrin or PDI4, proteins previously identified in porcine oviductal secretions, have a role in zona pellucida (ZP) resistance to enzymatic digestion, in vitro fertilization (IVF) and sperm viability. In vitro matured porcine cumulus oocyte complexes were denuded and i) incubated for 1 h in TALP medium supplemented or not with each exogenous oviductal protein and in presence or absence of heparin to assess ZP digestion time by pronase; and ii) inseminated with fresh ejaculated boar spermatozoa in medium supplemented or not with each exogenous oviductal protein to assess their effect on fertilization results. Finally, spermatozoa were incubated in Tyrode's medium (0, 1 and 20 h) supplemented or not with HSP-701A, HSP-90α or ezrin, to assess simultaneously sperm viability and acrosome status by means of flow cytometry. Although all proteins increased the ZP digestion time, this increase was lower than 1 min, being ezrin the protein with a stronger effect. Presence of heparin in the medium reinforced the ZP hardening effect of ezrin and HSP-701A up to one more min, but not HSP-90α nor PDI4. Sperm penetration, but not IVF efficiency, increased when gametes were cocultured in medium containing PDIA4 whereas sperm penetration and polyspermy rates decreased in presence of ezrin and HSP proteins. This reduction was not the result of a detrimental effect of proteins on sperm viability or acrosome reaction. In conclusion, addition of exogenous proteins detected in oviductal secretions to artificial media does not reproduce the effect of adding such secretions nor improve the final efficiency of the porcine IVF system.

Inflammasomes: Their Role in Normal and Complicated Pregnancies

Inflammasomes are cytoplasmic multiprotein complexes that coordinate inflammatory responses, including those that take place during pregnancy. Inflammasomes and their downstream mediators caspase-1 and IL-1β are expressed by gestational tissues (e.g., the placenta and chorioamniotic membranes) during normal pregnancy. Yet, only the activation of the NLRP3 inflammasome in the chorioamniotic membranes has been partially implicated in the sterile inflammatory process of term parturition. In vivo and ex vivo studies have consistently shown that the activation of the NLRP3 inflammasome is a mechanism whereby preterm labor and birth occur in the context of microbial- or alarmin-induced inflammation. In the placenta, the activation of the NLRP3 inflammasome is involved in the pathogenesis of preeclampsia and other pregnancy syndromes associated with placental inflammation. This evidence suggests that inhibition of the NLRP3 inflammasome or its downstream mediators may foster the development of novel anti-inflammatory therapies for the prevention or treatment of pregnancy complications.

Targeting Toll-like receptor-4 to tackle preterm birth and fetal inflammatory injury

Every year, 15 million pregnancies end prematurely, resulting in more than 1 million infant deaths and long-term health consequences for many children. The physiological processes of labour and birth involve essential roles for immune cells and pro-inflammatory cytokines in gestational tissues. There is compelling evidence that the mechanisms underlying spontaneous preterm birth are initiated when a premature and excessive inflammatory response is triggered by infection or other causes. Exposure to pro-inflammatory mediators is emerging as a major factor in the 'fetal inflammatory response syndrome' that often accompanies preterm birth, where unscheduled effects in fetal tissues interfere with normal development and predispose to neonatal morbidity. Toll-like receptors (TLRs) are critical upstream gatekeepers of inflammatory activation. TLR4 is prominently involved through its ability to sense and integrate signals from a range of microbial and endogenous triggers to provoke and perpetuate inflammation. Preclinical studies have identified TLR4 as an attractive pharmacological target to promote uterine quiescence and protect the fetus from inflammatory injury. Novel small-molecule inhibitors of TLR4 signalling, specifically the non-opioid receptor antagonists (+)-naloxone and (+)-naltrexone, are proving highly effective in animal models for preventing preterm birth induced by bacterial mimetic LPS, heat-killed Escherichia coli, or the TLR4-dependent pro-inflammatory lipid, platelet-activating factor (PAF). Here, we summarise the rationale for targeting TLR4 as a master regulator of inflammation in fetal and gestational tissues, and the potential utility of TLR4 antagonists as candidates for preventative and therapeutic application in preterm delivery and fetal inflammatory injury.

HSP70: an alarmin that does not induce high rates of preterm birth but does cause adverse neonatal outcomes

Objective: Preterm labor and birth are strongly associated with sterile intra-amniotic inflammation, a clinical condition that is proposed to be initiated by danger signals, or alarmins. The aim of this study was to investigate whether the intra-amniotic administration of the alarmin heat shock protein 70 (HSP70) induces preterm labor/birth and adverse neonatal outcomes.Methods: Pregnant mice received an intra-amniotic injection of 200 ng (n = 8), 400 ng (n = 6), 500 ng (n = 10), or 1 µg of HSP70 (n = 6). Control mice were injected with saline (n = 10). Following injection, the rates of preterm labor/birth and neonatal mortality were recorded. Neonatal weights at weeks 1, 2, and 3 were also recorded.Results: The intra-amniotic injection of 400 ng [late preterm birth 16.7 ± 16.7% (1/6)], 500 ng [early and late preterm birth 10 ± 10% (1/10) each], or 1 µg [early preterm birth 16.7 ± 16.7% (1/6)] of HSP70 induced low rates of preterm/birth. However, the intra-amniotic injection of 500 ng or 1 µg of HSP70 induced significantly higher rates of neonatal mortality compared to controls [saline 14.2% (10/74), 200 ng 9.8% (6/61), 400 ng 17.9% (9/45), 500 ng 28.8% (23/78), and 1 µg 21.4% (13/49)]. Neonates born to dams injected with 200, 500 ng, or 1 µg HSP70 were leaner than controls (p ≤ .05).Conclusion: Intra-amniotic administration of the alarmin HSP70 did not induce high rates of preterm labor/birth; yet, it did indeed result in adverse neonatal outcomes.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

MicroRNA-548 regulates high mobility group box 1 expression in patients with preterm birth and chorioamnionitis

High mobility group box 1 (HMGB1) is a prototypic alarmin and plays an important role in the pathogenesis of inflammatory process in spontaneous preterm birth. This study was conducted to compare the levels of HMGB1 in amniotic fluid and amnion membranes in women with chorioamnionitis/intra-amniotic inflammation to the levels in healthy controls. We also aimed to elucidate the involvement of microRNA-548 (miR-548) in regulating HMGB1 expression and its function in human amniotic epithelial cells (hAECs). A bioinformatics analysis predicted the binding of HMGB1 by the miR-548 cluster. A repressed and forced expression assay in hAECs was performed to investigate the causal relationship between the miR-548 cluster and HMGB1. The levels of HMGB1 in amniotic fluid and amnion membranes were significantly higher in patients with intra-amniotic inflammation/chorioamnionitis than in those without inflammation. The miR-548 was significantly under-expressed in amnion membranes from patients with chorioamnionitis than in normal term controls. Repressed expression of miR-548 up-regulated HMGB1 expression in hAECs and increased its release from hAECs. Moreover, forced expression of miR-548 suppressed HMGB1 and inflammatory cytokines in hAECs, which increased when treated with lipopolysaccharide. These results suggest miR-548 can alter the inflammatory responses in hAECs, and might be involved in the pathogenesis of preterm birth by regulating HMGB1.

The origin of amniotic fluid monocytes/macrophages in women with intra-amniotic inflammation or infection

Background Monocytes, after neutrophils, are the most abundant white blood cells found in the amniotic cavity of women with intra-amniotic inflammation/infection. However, the origin of such cells has not been fully investigated. Herein, we determined (1) the origin of amniotic fluid monocytes/macrophages from women with intra-amniotic inflammation/infection, (2) the relationship between the origin of amniotic fluid monocytes/macrophages and preterm or term delivery and (3) the localization of monocytes/macrophages in the placental tissues. Methods Amniotic fluid samples (n = 16) were collected from women with suspected intra-amniotic inflammation or infection. Amniotic fluid monocytes/macrophages were purified by fluorescence-activated cell sorting, and DNA fingerprinting was performed. Blinded placental histopathological evaluations were conducted. Immunohistochemistry was performed to detect CD14+ monocytes/macrophages in the placental tissues. Results DNA fingerprinting revealed that (1) 56.25% (9/16) of amniotic fluid samples had mostly fetal monocytes/macrophages, (2) 37.5% (6/16) had predominantly maternal monocytes/macrophages and (3) one sample (6.25% [1/16]) had a mixture of fetal and maternal monocytes/macrophages. (4) Most samples with predominantly fetal monocytes/macrophages were from women who delivered early preterm neonates (77.8% [7/9]), whereas all samples with mostly maternal monocytes/macrophages or a mixture of both were from women who delivered term or late preterm neonates (100% [7/7]). (5) Most of the women included in this study presented acute maternal and fetal inflammatory responses in the placenta (85.7% [12/14]). (6) Women who had mostly fetal monocytes/macrophages in amniotic fluid had abundant CD14+ cells in the umbilical cord and chorionic plate, whereas women with mostly maternal amniotic fluid monocytes/macrophages had abundant CD14+ cells in the chorioamniotic membranes. Conclusion Amniotic fluid monocytes/macrophages can be of either fetal or maternal origin, or a mixture of both, in women with intra-amniotic inflammation or infection. These immune cells could be derived from the fetal and maternal vasculature of the placenta.

Vaginal Biomarkers That Predict Cervical Length and Dominant Bacteria in the Vaginal Microbiomes of Pregnant Women

In many impoverished regions of the world, it may not be possible to assess two major risk factors for preterm birth: a short cervical length and the depletion of vaginal lactobacilli. We determined whether measuring specific compounds in vaginal fluid might be a simple, noninvasive, and cost-effective way to predict the bacteria that dominate the vaginal microbiome and indicate the presence of a shortened cervix (<25 mm). Vaginal fluid samples were prospectively collected from mid-trimester pregnant women, and the concentrations of d- and l-lactic acid, tissue inhibitor of matrix metalloproteinases TIMP-1 and TIMP-2, matrix metalloproteinases MMP-2 and MMP-8, the 70-kDa heat shock protein, a2 isoform of vacuolar ATPase, and sequestrome-1 were quantified by an enzyme-linked immunosorbent assay (ELISA). The compositions of vaginal microbiomes were assessed by analysis of the V1-V3 regions of 16S rRNA genes, while cervical length was determined by transvaginal ultrasonography. The vaginal microbiomes could be clustered into five community state types (CSTs), four of which were dominated by a single Lactobacillus species. The dominance of Lactobacillus crispatus or Lactobacillus jensenii in the vaginal microbiome predicted the level of d-lactic acid present. Several of the biomarkers, especially TIMP-1, in combination with the subject's age and race, were significantly associated with cervical length. Using piecewise structural equation modeling, we established a causal network that links CST to cervical length via biomarkers. We concluded that measuring levels of TIMP-1 and d-lactic acid in vaginal secretions might be a straightforward way to assess the risk for preterm birth due to a short cervix and microbiome composition.IMPORTANCE Premature birth and its complications are the largest contributors to infant death in the United States and globally. A short cervical length and the depletion of Lactobacillus species are known risk factors for preterm birth. However, in many resource-poor areas of the world, the technology to test for their occurrence is unavailable, and pregnant women with these risk factors are neither identified nor treated. In this study, we used path analysis to gain an unprecedented understanding of interactions between vaginal microbiome composition, the concentrations of various compounds in vaginal secretions, and cervical length. We identified low-cost point-of-care measures that might be used to identify pregnant women at risk for preterm birth. The use of these measures coupled with appropriate preventative or treatment strategies could reduce the incidence of preterm births in poor areas of the world that lack access to more sophisticated diagnostic methods.

Fetal T Cell Activation in the Amniotic Cavity during Preterm Labor: A Potential Mechanism for a Subset of Idiopathic Preterm Birth

Prematurity is the leading cause of perinatal morbidity and mortality worldwide. In most cases, preterm birth is preceded by spontaneous preterm labor, a syndrome that is associated with intra-amniotic inflammation, the most studied etiology. However, the remaining etiologies of preterm labor are poorly understood; therefore, most preterm births are categorized as idiopathic. In this study, we provide evidence showing that the fetal immune system undergoes premature activation in women with preterm labor without intra-amniotic inflammation, providing a potential new mechanism of disease for some cases of idiopathic preterm birth. First, we showed that fetal T cells are a predominant leukocyte population in amniotic fluid during preterm gestations. Interestingly, only fetal CD4+ T cells were increased in amniotic fluid of women who underwent idiopathic preterm labor and birth. This increase in fetal CD4+ T cells was accompanied by elevated amniotic fluid concentrations of T cell cytokines such as IL-2, IL-4, and IL-13, which are produced by these cells upon in vitro stimulation, but was not associated with the prototypical cytokine profile observed in women with intra-amniotic inflammation. Also, we found that cord blood T cells, mainly CD4+ T cells, obtained from women with idiopathic preterm labor and birth displayed enhanced ex vivo activation, which is similar to that observed in women with intra-amniotic inflammation. Finally, we showed that the intra-amniotic administration of activated neonatal CD4+ T cells induces preterm birth in mice. Collectively, these findings provide evidence suggesting that fetal T cell activation is implicated in the pathogenesis of idiopathic preterm labor and birth.

Gasdermin D: Evidence of pyroptosis in spontaneous preterm labor with sterile intra-amniotic inflammation or intra-amniotic infection

PROBLEM

Pyroptosis, inflammatory programmed cell death, is initiated through the inflammasome and relies on the pore-forming actions of the effector molecule gasdermin D. Herein, we investigated whether gasdermin D is detectable in women with spontaneous preterm labor and sterile intra-amniotic inflammation or intra-amniotic infection.

METHOD OF STUDY

Amniotic fluid samples (n = 124) from women with spontaneous preterm labor were subdivided into the following groups: (a) those who delivered at term (n = 32); and those who delivered preterm (b) without intra-amniotic inflammation (n = 41), (c) with sterile intra-amniotic inflammation (n = 32), or (d) with intra-amniotic infection (n = 19), based on amniotic fluid IL-6 concentrations and the microbiological status of amniotic fluid (culture and PCR/ESI-MS). Gasdermin D concentrations were measured using an ELISA kit. Multiplex immunofluorescence staining was also performed to determine the expression of gasdermin D, caspase-1, and interleukin-1β in the chorioamniotic membranes. Flow cytometry was used to detect pyroptosis (active caspase-1) in decidual cells from women with preterm labor and birth.

RESULTS

(a) Gasdermin D was detected in the amniotic fluid and chorioamniotic membranes from women who underwent spontaneous preterm labor/birth with either sterile intra-amniotic inflammation or intra-amniotic infection, but was rarely detected in those without intra-amniotic inflammation. (b) Amniotic fluid concentrations of gasdermin D were higher in women with intra-amniotic infection than in those with sterile intra-amniotic inflammation, and its expression in the chorioamniotic membranes was associated with caspase-1 and IL-1β (inflammasome mediators). (c) Decidual stromal cells and leukocytes isolated from women with preterm labor and birth are capable of undergoing pyroptosis given their expression of active caspase-1.

CONCLUSION

Pyroptosis can occur in the context of sterile intra-amniotic inflammation and intra-amniotic infection in patients with spontaneous preterm labor and birth.

Cellular immune responses in amniotic fluid of women with preterm labor and intra-amniotic infection or intra-amniotic inflammation

PROBLEM

Preterm birth is commonly preceded by preterm labor, a syndrome that is causally linked to both intra-amniotic infection and intra-amniotic inflammation. However, the stereotypical cellular immune responses in these two clinical conditions are poorly understood.

METHOD OF STUDY

Amniotic fluid samples (n = 26) were collected from women diagnosed with preterm labor and intra-amniotic infection (amniotic fluid IL-6 concentrations ≥2.6 ng/mL and culturable microorganisms, n = 10) or intra-amniotic inflammation (amniotic fluid IL-6 concentrations ≥2.6 ng/mL without culturable microorganisms, n = 16). Flow cytometry was performed to evaluate the phenotype and number of amniotic fluid leukocytes. Amniotic fluid concentrations of classical pro-inflammatory cytokines, type 1 and type 2 cytokines, and T-cell chemokines were determined using immunoassays.

RESULTS

Women with spontaneous preterm labor and intra-amniotic infection had (a) a greater number of total leukocytes, including neutrophils and monocytes/macrophages, in amniotic fluid; (b) a higher number of total T cells and CD4⁺ T cells, but not CD8⁺ T cells or B cells, in amniotic fluid; and (c) increased amniotic fluid concentrations of IL-6, IL-1β, and IL-10, compared to those with intra-amniotic inflammation. However, no differences in amniotic fluid concentrations of T-cell cytokines and chemokines were observed between these two clinical conditions.

CONCLUSION

The cellular immune responses observed in women with preterm labor and intra-amniotic infection are more severe than in those with intra-amniotic inflammation, and neutrophils, monocytes/macrophages, and CD4⁺ T cells are the main immune cells responding to microorganisms that invade the amniotic cavity. These findings provide insights into the intra-amniotic immune mechanisms underlying the human syndrome of preterm labor.

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.

Are B cells altered in the decidua of women with preterm or term labor?

PROBLEM

The immunophenotype of B cells at the maternal-fetal interface (decidua) in labor at term and preterm labor is poorly understood.

METHOD OF STUDY

Decidual tissues were obtained from women with preterm or term labor and from non-labor gestational age-matched controls. Immunophenotyping of decidual B cells was performed using multicolor flow cytometry.

RESULTS

(a) In the absence of acute or chronic chorioamnionitis, total B cells were more abundant in the decidua parietalis of women who delivered preterm than in those who delivered at term, regardless of the presence of labor; (b) decidual transitional and naïve B cells were the most abundant B-cell subsets; (c) decidual B1 B cells were increased in women with either labor at term or preterm labor and chronic chorioamnionitis compared to those without this placental lesion; (d) decidual transitional B cells were reduced in women with preterm labor compared to those without labor; (e) naïve, class-switched, and non-class-switched B cells in the decidual tissues underwent mild alterations with the process of preterm labor; (f) decidual plasmablasts seemed to increase in women with either labor at term or preterm labor with chronic chorioamnionitis; and (g) decidual B cells expressed high levels of interleukin (IL)-12, IL-6, and/or IL-35.

CONCLUSION

Total B cells are not increased with the presence of preterm or term labor; yet, specific subsets (B1 and plasmablasts) undergo alterations in women with chronic chorioamnionitis. Therefore, B cells are solely implicated in the pathological process of preterm labor in a subset of women with chronic inflammation of the placenta. These findings provide insight into the immunology of the maternal-fetal interface in preterm and term labor.

Amnion epithelial cell-derived exosomes induce inflammatory changes in uterine cells

BACKGROUND

Fetal endocrine signals are generally considered to contribute to the timing of birth and the initiation of labor. Fetal tissues under oxidative stress release inflammatory mediators that lead to sterile inflammation within the maternal-fetal interface. Importantly, these inflammatory mediators are packaged into exosomes, bioactive cell-derived extra cellular vesicles that function as vectors and transport them from the fetal side to the uterine tissues where they deposit their cargo into target cells enhancing uterine inflammatory load. This exosome-mediated signaling is a novel mechanism for fetal-maternal communication.

OBJECTIVE

This report tested the hypothesis that oxidative stress can induce fetal amnion cells to produce exosomes, which function as a paracrine intermediary between the fetus and mother and biochemically signal readiness for parturition.

STUDY DESIGN

Primary amnion epithelial cells were grown in normal cell culture (control) or exposed to oxidative stress conditions (induced by cigarette smoke extract). Exosomes were isolated from cell supernatant by sequential ultracentrifugation. Exosomes were quantified and characterized based on size, shape, and biochemical markers. Myometrial, decidual, and placental cells (BeWo) were treated with 2 × 105, 2 × 107, and 2 × 109 control or oxidative stress-derived amnion epithelial cell exosomes for 24 hours. Entry of amnion epithelial cell exosomes into cells was confirmed by confocal microscopy of fluorescent-labeled exosomes. The effect of amnion epithelial cell exosomes on target cell inflammatory status was determined by measuring production of interleukin-6, interleukin-8, interleukin-1β, tumor necrosis factor-α, and prostaglandin E2 by enzyme-linked immunosorbent assay and inflammatory gene transcription factor (nuclear factor-κβ) activation status by immunoblotting for phosphorylated RelA/p65. Localization of NANOG in term human myometrium and decidua obtained from women before labor and during labor was performed using immunohistochemistry. Data were analyzed by Wilcoxon-Mann-Whitney test to compare effects of exosomes from control and oxidative stress-treated amnion epithelial cells on inflammatory status of target cells.

RESULTS

Amnion epithelial cells released ∼125 nm, cup-shaped exosomes with ∼899 and 1211 exosomes released per cell from control and oxidative stress-induced cells, respectively. Amnion epithelial cell exosomes were detected in each target cell type after treatment using confocal microscopy. Treatment with amnion epithelial cell exosomes increased secretion of interleukin-6, interleukin-8, and PGE2 and activation of NF-κβ (each P < .05) in myometrial and decidual cells. Exosome treatments had no effect on interleukin-6 and PGE2 production in BeWo cells. NANOG staining was higher in term labor myometrium and decidua compared to tissues not in labor.

CONCLUSION

In vitro, amnion epithelial cell exosomes lead to an increased inflammatory response in maternal uterine cells whereas placental cells showed refractoriness. Fetal cell exosomes may function to signal parturition by increasing maternal gestational cell inflammation.

Inflammasome activation during spontaneous preterm labor with intra-amniotic infection or sterile intra-amniotic inflammation

PROBLEM

The inflammasome is implicated in the mechanisms that lead to spontaneous preterm labor (PTL). However, whether there is inflammasome activation in the amniotic cavity of women with PTL and intra-amniotic infection (IAI) or sterile intra-amniotic inflammation (SIAI) is unknown.

METHOD OF STUDY

Amniotic fluid samples were collected from women with PTL who delivered at term (n = 31) or preterm without IAI or SIAI (n = 35), with SIAI (n = 27), or with IAI (n = 17). As a readout of inflammasome activation, extracellular ASC (apoptosis-associated speck-like protein containing a CARD) was measured in amniotic fluid by ELISA and the expression of ASC, caspase-1, and interleukin (IL)-1β was detected in the chorioamniotic membranes by multiplex immunofluorescence. Acute inflammatory responses in amniotic fluid and the placenta were also evaluated.

RESULTS

(a) Amniotic fluid concentrations of ASC and IL-6 were higher in women with PTL and IAI or SIAI than in those who delivered preterm or at term without intra-amniotic inflammation; (b) amniotic fluid concentrations of ASC and IL-6 were lower in women with PTL and SIAI than in those with IAI; (c) there was a significant nonlinear correlation between ASC and IL-6 amniotic fluid concentrations; (d) the expression of inflammasome-related proteins (ASC, caspase-1, and IL-1β) in the chorioamniotic membranes was increased in women with PTL and IAI or SIAI than in those who delivered preterm or at term without intra-amniotic inflammation; (e) inflammasome activation in the chorioamniotic membranes was weaker in women with PTL and SIAI than in those with IAI; (f) women with PTL and IAI had elevated amniotic fluid white blood cell counts compared to those without this clinical condition; and (g) severe acute placental inflammatory lesions were observed in women with PTL and IAI and in a subset of women with PTL and SIAI.

CONCLUSION

Inflammasome activation occurs in the settings of intra-amniotic infection and sterile intra-amniotic inflammation during spontaneous preterm labor.

The frequency and type of placental histologic lesions in term pregnancies with normal outcome

Objective To determine the frequency and type of histopathologic lesions in placentas delivered by women with a normal pregnancy outcome. Methods This retrospective cohort study included placental samples from 944 women with a singleton gestation who delivered at term without obstetrical complications. Placental lesions were classified into the following four categories as defined by the Society for Pediatric Pathology and by our unit: (1) acute placental inflammation, (2) chronic placental inflammation, (3) maternal vascular malperfusion and (4) fetal vascular malperfusion. Results (1) Seventy-eight percent of the placentas had lesions consistent with inflammatory or vascular lesions; (2) acute inflammatory lesions were the most prevalent, observed in 42.3% of the placentas, but only 1.0% of the lesions were severe; (3) acute inflammatory lesions were more common in the placentas of women with labor than in those without labor; (4) chronic inflammatory lesions of the placenta were present in 29.9%; and (5) maternal and fetal vascular lesions of malperfusion were detected in 35.7% and 19.7%, respectively. Two or more lesions with maternal or fetal vascular features consistent with malperfusion (high-burden lesions) were present in 7.4% and 0.7%, respectively. Conclusion Most placentas had lesions consistent with inflammatory or vascular lesions, but severe and/or high-burden lesions were infrequent. Mild placental lesions may be interpreted either as acute changes associated with parturition or as representative of a subclinical pathological process (intra-amniotic infection or sterile intra-amniotic inflammation) that did not affect the clinical course of pregnancy.

Secretion of heat shock -60, -70 kD protein, IL-1β and TNFα levels in serum of a term normal pregnancy and patients with pre-eclampsia development

The extracellular heat shock proteins (eHsp) family act as molecular chaperones regulating folding, transporting protein and are associated with immune modulation in different physiological and pathological processes. They have been localized in different gestational tissues and their concentration in amniotic fluid and serum has been determined. In the present study, we proposed to determine the concentration of eHsp‐60, ‐70, IL‐1β and TNFα in the serum of pregnant patients with 34 weeks of gestation with and without clinical evidences of preeclampsia (PE). Our results indicate significant increase of these markers in patients with PE with respect to healthy pregnant patients without active labor. Finally, the concentration of eHsp‐60 and ‐70 correlated positively with the hepatic dysfunction markers uric acid, lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT) glutamic pyruvic transaminase (GPT), and inflammatory IL‐1β and TNFα response. In conclusion, our results demonstrate a strong associated between Hsp and marker of hepatic dysfunction.

Whole exome sequencing reveals HSPA1L as a genetic risk factor for spontaneous preterm birth

Preterm birth is a leading cause of morbidity and mortality in infants. Genetic and environmental factors play a role in the susceptibility to preterm birth, but despite many investigations, the genetic basis for preterm birth remain largely unknown. Our objective was to identify rare, possibly damaging, nucleotide variants in mothers from families with recurrent spontaneous preterm births (SPTB). DNA samples from 17 Finnish mothers who delivered at least one infant preterm were subjected to whole exome sequencing. All mothers were of northern Finnish origin and were from seven multiplex families. Additional replication samples of European origin consisted of 93 Danish sister pairs (and two sister triads), all with a history of a preterm delivery. Rare exonic variants (frequency <1%) were analyzed to identify genes and pathways likely to affect SPTB susceptibility. We identified rare, possibly damaging, variants in genes that were common to multiple affected individuals. The glucocorticoid receptor signaling pathway was the most significant (p<1.7e-8) with genes containing these variants in a subgroup of ten Finnish mothers, each having had 2-4 SPTBs. This pathway was replicated among the Danish sister pairs. A gene in this pathway, heat shock protein family A (Hsp70) member 1 like (HSPA1L), contains two likely damaging missense alleles that were found in four different Finnish families. One of the variants (rs34620296) had a higher frequency in cases compared to controls (0.0025 vs. 0.0010, p = 0.002) in a large preterm birth genome-wide association study (GWAS) consisting of mothers of general European ancestry. Sister pairs in replication samples also shared rare, likely damaging HSPA1L variants. Furthermore, in silico analysis predicted an additional phosphorylation site generated by rs34620296 that could potentially affect chaperone activity or HSPA1L protein stability. Finally, in vitro functional experiment showed a link between HSPA1L activity and decidualization. In conclusion, rare, likely damaging, variants in HSPA1L were observed in multiple families with recurrent SPTB.

Clinical Chorioamnionitis at Term: New Insights into the Etiology, Microbiology, and the Fetal, Maternal and Amniotic Cavity Inflammatory Responses

Clinical chorioamnionitis is the most common infection related diagnosis made in labor and delivery units worldwide. It is traditionally believed to be due to microbial invasion of the amniotic cavity, which elicits a maternal inflammatory response characterized by maternal fever, uterine tenderness, maternal tachycardia and leukocytosis. The condition is often associated with fetal tachycardia and a foul smelling amniotic fluid. Recent studies in which amniocentesis has been used to characterize the microbiologic state of the amniotic cavity and the inflammatory response show that only 60% of patients with the diagnosis of clinical chorioamnionitis have proven infection using culture or molecular microbiologic techniques. The remainder of the patients have intra-amniotic inflammation without demonstrable microorganisms or a maternal systemic inflammatory response (fever) in the absence of intra-amniotic inflammation. The latter cases often represent a systemic inflammatory response after epidural anesthesia/analgesia has been administered. The most common microorganisms are Ureaplasma species and Gardnerella vaginalis. In the presence of ruptured membranes, the frequency of infection is 70%, which is substantially higher than patients who have intact membranes (25%). The amniotic fluid inflammatory response is characterized by an infiltration of neutrophils and monocytes. Both cell types are activated in the presence of infection and can produce inflammatory cytokines. The white blood cells in the amniotic fluid can be of fetal or maternal origin. The maternal inflammatory response is characterized by an elevation in the concentration of pyrogenic cytokines. The cytokine plasma concentrations in the fetal circulation are elevated even if there is no evidence of an intra-amniotic inflammatory response suggesting that maternal plasma cytokines may cross the placental barrier and induce a mild fetal inflammatory response. Placental pathology is of limited value in the diagnosis of proven intra-amniotic infection. The clinical criteria traditionally used in clinical medicine have accuracy around 50% and therefore, they cannot distinguish between patients with a proven intra-amniotic infection and those with intra-amniotic inflammation alone. Analysis of amniotic fluid with a bedside test for MMP-8 can allow the rapid identification of the patient at risk for infection and may decrease the need for antibiotic administration to neonates. An important consideration is whether antibiotics effective against Ureaplasma species should be administered to patients with clinical chorioamnionitis, given that these genital mycoplasmas are the most common organisms found in the amniotic fluid. The emergent picture is that clinical chorioamnionitis is a heterogeneous syndrome, which requires further study to optimize maternal and neonatal outcomes.

Innate lymphoid cells at the human maternal-fetal interface in spontaneous preterm labor

PROBLEM

Pathological inflammation is causally linked to preterm labor and birth, the leading cause of neonatal morbidity and mortality worldwide. Our aims were to investigate whether (i) the newly described family of innate lymphoid cells (ILCs) was present at the human maternal-fetal interface and (ii) ILC inflammatory subsets were associated with the pathological process of preterm labor.

METHODS OF STUDY

Decidual leukocytes were isolated from women with preterm or term labor as well as from gestational age-matched non-labor controls. ILCs (CD15- CD14- CD3- CD19- CD56- CD11b- CD127+ cells) and their subsets (ILC1, T-bet+ ILCs; ILC2, GATA3+ ILCs; and ILC3, RORγt+ ILCs) and cytokine expression were identified in the decidual tissues using immunophenotyping.

RESULTS

(i) The proportion of total ILCs was increased in the decidua parietalis of women with preterm labor; (ii) ILC1s were a minor subset of decidual ILCs during preterm and term gestations; (iii) ILC2s were the most abundant ILC subset in the decidua during preterm and term gestations; (iv) the proportion of ILC2s was increased in the decidua basalis of women with preterm labor; (v) the proportion of ILC3s was increased in the decidua parietalis of women with preterm labor; and (vi) during preterm labor, ILC3s had higher expression of IL-22, IL-17A, IL-13, and IFN-γ compared to ILC2s in the decidua.

CONCLUSION

ILC2s were the most abundant ILC subset at the human maternal-fetal interface during preterm and term gestations. Yet, during preterm labor, an increase in ILC2s and ILC3s was observed in the decidua basalis and decidua parietalis, respectively. These findings provide evidence demonstrating a role for ILCs at the maternal-fetal interface during the pathological process of preterm labor.

CXCL10 and IL-6: Markers of two different forms of intra-amniotic inflammation in preterm labor

Problem

To determine whether amniotic fluid (AF) CXCL10 concentration is associated with histologic chronic chorioamnionitis in patients with preterm labor (PTL) and preterm prelabor rupture of the membranes (PROM).

Method of Study

This study included 168 women who had an episode of PTL or preterm PROM. AF interleukin (IL)‐6 and CXCL10 concentrations were determined by immunoassay.

Results

(i) Increased AF CXCL10 concentration was associated with chronic (OR: 4.8; 95% CI: 1.7‐14), but not acute chorioamnionitis; (ii) increased AF IL‐6 concentration was associated with acute (OR: 4.2; 95% CI: 1.3‐13.7) but not chronic chorioamnionitis; and (iii) an increase in AF CXCL10 concentration was associated with placental lesions consistent with maternal anti‐fetal rejection (OR: 3.7; 95% CI: 1.3‐10.4). (iv) All patients with elevated AF CXCL10 and IL‐6 delivered preterm.

Conclusion

Increased AF CXCL10 concentration is associated with chronic chorioamnionitis or maternal anti‐fetal rejection, whereas increased AF IL‐6 concentration is associated with acute histologic chorioamnionitis.

[Effect of heat exposure in the second trimester of pregnancy on intrauterine growth of fatal rat and the expression of HSP70, Bax and Bcl-2 of placenta]

OBJECTIVE

To investigate the effect of heat exposure during the second week of pregnancy on placental development and intrauterine growth of fetal rats.

METHODS

24 pregnant rats were either exposed or not to a temperature of 35∓1 degrees celsius; during the second week of pregnancy. The body weight gain of the pregnant rats was measured regularly, and in late pregnancy, the pregnant rats were dissected and the number, weight, length, tail length, appearance of the offspring rats, number of live and still births, and the placental weight were recorded. The expressions of HSP70, Bax and Bcl-2 in the placenta were determined.

RESULTS

Compared with the control group, the pregnant rats in heat exposure group had significantly lower body weight at the end of pregnancy and gestational weight gain, and the body weight, body length and tail length of the offspring rats were also significantly lower or smaller (P<0.05). The placental weight was comparable between the two groups. The placental expressions of HSP70,Bax,and Bcl-2 were significantly higher in the heat exposure group than in the control group (P<0.05).

CONCLUSION

Heat exposure during the second trimester of pregnancy has adverse effects on placental development and intrauterine growth of the fetal rats by inducing heat shock response of placental tissue and apoptosis of the placental cells.

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.

HMGB1 Induces an Inflammatory Response in the Chorioamniotic Membranes That Is Partially Mediated by the Inflammasome

Spontaneous preterm labor occurs in two subsets of patients with sterile intra-amniotic inflammation, a process induced by alarmins such as high-mobility group box-1 (HMGB1). Inflammasomes are implicated in the process of spontaneous preterm labor. Therefore, we investigated whether HMGB1 initiates an inflammasome-associated inflammatory response in the chorioamniotic membranes. Incubation of the chorioamniotic membranes with HMGB1 1) induced the release of mature IL-1beta and IL-6; 2) upregulated the mRNA expression of the pro-inflammatory mediators NFKB1, IL6, TNF, IL1A, IFNG, and HMGB1 receptors RAGE and TLR2; 3) upregulated the mRNA expression of the inflammasome components NLRP3 and AIM2 as well as NOD proteins (NOD1 and NOD2); 4) increased the protein concentrations of NLRP3 and NOD2; 5) increased the concentration of caspase-1 and the quantity of its active form (p20); and 6) upregulated the mRNA expression and active form of MMP-9. In addition, HMGB1 concentrations in chorioamniotic membrane extracts from women who underwent spontaneous preterm labor were greater than in those from women who had undergone spontaneous labor at term. Collectively, these results show that HMGB1 can induce an inflammatory response in the chorioamniotic membranes, which is partially mediated by the inflammasome. These results provide insight into the mechanisms whereby HMGB1 induces preterm labor and birth in mice and explain why the concentration of this alarmin is increased in women who undergo spontaneous preterm labor.

Intra-Amniotic Administration of HMGB1 Induces Spontaneous Preterm Labor and Birth

PROBLEM

Sterile intra-amniotic inflammation is associated with spontaneous preterm labor. Alarmins are proposed to mediate this inflammatory process. The aim of this study was to determine whether intra-amniotic administration of an alarmin, HMGB1, could induce preterm labor/birth.

METHOD OF STUDY

Pregnant B6 mice were intra-amniotically or intraperitoneally injected with HMGB1 or PBS (control). Following injection, the gestational age and the rates of preterm birth and pup mortality were recorded.

RESULTS

Intra-amniotic injection of HMGB1 led to preterm labor/birth [HMGB1 57% (4/7) versus PBS 0% (0/6); P = 0.049) and a high rate of pup mortality at week 1 [HMGB1 60.9 ± 11.7% (25/41) versus PBS 28.9 ± 12.6% (11/38); P = 0.001). Intraperitoneal injection of HMGB1 did not induce preterm labor/birth.

CONCLUSION

Intra-amniotic administration of HMGB1 induces preterm labor/birth.

Diagnostic Potential of Evaluation of SDF-1α and sRAGE Levels in Threatened Premature Labor

Preterm birth remains the most prevalent cause of neonatal morbidity. This study aimed to evaluate the diagnostic value of SDF-1α, resistin, secretory RAGE (sRAGE), and endogenous secretory RAGE (esRAGE) in preterm labor. A total of 211 pregnant women participated in the study. Group A contained 72 women between 22 and 36 weeks of gestation, with premature labor, who finally had preterm birth. Group B contained 66 women in labor between 37 and 41 weeks of gestation. Women in group A had lower SDF-1α and sRAGE levels than those in group B. Moreover, in group A, SDF-1α and sRAGE levels were correlated with the latency period from the occurrence of premature labor symptoms until delivery. Sensitivity and specificity of studied parameters for prediction of preterm birth were 95% and 40% for SDF-1α and 51.3% and 93.5% for sRAGE, respectively. The prognostic value of plasma SDF-1α and sRAGE levels was comparable with that of cervical length ultrasound measurement and serum C-reactive protein levels. We conclude that SDF-1α and sRAGE appear to play a major role in the diagnosis of preterm birth and its evaluation could be convenient and useful for predicting preterm birth.

Invariant NKT Cell Activation Induces Late Preterm Birth That Is Attenuated by Rosiglitazone

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. Although intra-amniotic infection is a recognized cause of spontaneous preterm labor, the noninfection-related etiologies are poorly understood. In this article, we demonstrated that the expansion of activated CD1d-restricted invariant NKT (iNKT) cells in the third trimester by administration of α-galactosylceramide (α-GalCer) induced late PTB and neonatal mortality. In vivo imaging revealed that fetuses from mice that underwent α-GalCer-induced late PTB had bradycardia and died shortly after delivery. Yet, administration of α-GalCer in the second trimester did not cause pregnancy loss. Peroxisome proliferator-activated receptor (PPAR)γ activation, through rosiglitazone treatment, reduced the rate of α-GalCer-induced late PTB and improved neonatal survival. Administration of α-GalCer in the third trimester suppressed PPARγ activation, as shown by the downregulation of Fabp4 and Fatp4 in myometrial and decidual tissues, respectively; this suppression was rescued by rosiglitazone treatment. Administration of α-GalCer in the third trimester induced an increase in the activation of conventional CD4(+) T cells in myometrial tissues and the infiltration of activated macrophages, neutrophils, and mature dendritic cells to myometrial and/or decidual tissues. All of these effects were blunted after rosiglitazone treatment. Administration of α-GalCer also upregulated the expression of inflammatory genes at the maternal-fetal interface and systemically, and rosiglitazone treatment partially attenuated these responses. Finally, an increased infiltration of activated iNKT-like cells in human decidual tissues is associated with noninfection-related preterm labor/birth. Collectively, these results demonstrate that iNKT cell activation in vivo leads to late PTB by initiating innate and adaptive immune responses and suggest that the PPARγ pathway has potential as a target for prevention of this syndrome.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

Clinical chorioamnionitis at term III: how well do clinical criteria perform in the identification of proven intra-amniotic infection?

OBJECTIVE

The diagnosis of clinical chorioamnionitis is based on a combination of signs [fever, maternal or fetal tachycardia, foul-smelling amniotic fluid (AF), uterine tenderness and maternal leukocytosis]. Bacterial infections within the amniotic cavity are considered the most frequent cause of clinical chorioamnionitis and an indication for antibiotic administration to reduce maternal and neonatal morbidity. Recent studies show that only 54% of patients with the diagnosis of clinical chorioamnionitis at term have bacteria in the AF and evidence of intra-amniotic inflammation. The objective of this study was to examine the performance of the clinical criteria for the diagnosis of chorioamnionitis to identify patients with microbial-associated intra-amniotic inflammation (also termed intra-amniotic infection).

MATERIALS AND METHODS

This retrospective cross-sectional study included 45 patients with the diagnosis of clinical chorioamnionitis at term, whose AF underwent analysis for: 1) the presence of microorganisms using both cultivation and molecular biologic techniques [polymerase chain reaction (PCR) with broad primers], and 2) interleukin (IL)-6 concentrations by enzyme-linked immunosorbent assay. The diagnostic performance (sensitivity, specificity, accuracy, and likelihood ratios) of each clinical sign and their combination to identify clinical chorioamnionitis were determined using microbial-associated intra-amniotic inflammation [presence of microorganisms in the AF using cultivation or molecular techniques and elevated AF IL-6 concentrations (≥2.6 ng/mL)] as the gold standard.

RESULTS

The accuracy of each clinical sign for the identification of microbial-associated intra-amniotic inflammation (intra-amniotic infection) ranged between 46.7% and 57.8%. The combination of fever with three or more clinical criteria did not substantially improve diagnostic accuracy.

CONCLUSION

In the presence of a fever during labor at term, signs used to diagnose clinical chorioamnionitis do not accurately identify the patient with proven intra-amniotic infection (i.e., those with microorganisms detected by culture or molecular microbiologic techniques and an associated intra-amniotic inflammatory response).

Maternal immunity and pregnancy outcome: focus on preconception and autophagy

Modulation of the maternal immune system before conception has a major role in determining subsequent pregnancy outcome. However, this has been a neglected area of investigation. There is a correlation between the length of time a woman is exposed to semen from her male partner and the development of regulatory T cells that limit a maternal antifetal immune response. Similarly, the composition of the vaginal microbiota influences the capacity of microorganisms to bypass the cervical barrier and colonize the uterus before pregnancy. The extent that this preconception colonization influences pre- and post-implantation gestational events depends on the types of microbes present, the genetic make-up of the mother and environmental influences on the magnitude and direction of her immune responses. Prepregnancy uterine and placental colonization with commensal bacteria may be beneficial to the fetus and newborn by generating tolerance to organisms that enhance postnatal well-being. Efforts to prevent or stop the progression of premature myometrial contractions have been limited because of an incomplete understanding of the mechanism(s) that trigger this occurrence. Based on recent studies of autophagy during gestation and parturition, inhibition of autophagy in myometrial cells may be the critical factor leading to a sequence of events culminating in induction of myometrial contractions either prematurely or at term.

Immunomodulatory activity of extracellular Hsp70 mediated via paired receptors Siglec-5 and Siglec-14

The intracellular chaperone heat-shock protein 70 (Hsp70) can be secreted from cells, but its extracellular role is unclear, as the protein has been reported to both activate and suppress the innate immune response. Potential immunomodulatory receptors on myelomonocytic lineage cells that bind extracellular Hsp70 are not well defined. Siglecs are Ig-superfamily lectins on mammalian leukocytes that recognize sialic acid-bearing glycans and thereby modulate immune responses. Siglec-5 and Siglec-14, expressed on monocytes and neutrophils, share identical ligand-binding domains but have opposing signaling functions. Based on phylogenetic analyses of these receptors, we predicted that endogenous sialic acid-independent ligands should exist. An unbiased screen revealed Hsp70 as a ligand for Siglec-5 and Siglec-14. Hsp70 stimulation through Siglec-5 delivers an anti-inflammatory signal, while stimulation through Siglec-14 is pro-inflammatory. The functional consequences of this interaction are also addressed in relation to a SIGLEC14 polymorphism found in humans. Our results demonstrate that an endogenous non-sialic acid-bearing molecule can be either a danger-associated or self-associated signal through paired Siglecs, and may explain seemingly contradictory prior reports on extracellular Hsp70 action.

Acute chorioamnionitis and funisitis: definition, pathologic features, and clinical significance

Acute inflammatory lesions of the placenta consist of diffuse infiltration of neutrophils at different sites in the organ. These lesions include acute chorioamnionitis, funisitis, and chorionic vasculitis and represent a host response (maternal or fetal) to a chemotactic gradient in the amniotic cavity. While acute chorioamnionitis is evidence of a maternal host response, funisitis and chorionic vasculitis represent fetal inflammatory responses. Intraamniotic infection generally has been considered to be the cause of acute chorioamnionitis and funisitis; however, recent evidence indicates that "sterile" intraamniotic inflammation, which occurs in the absence of demonstrable microorganisms induced by "danger signals," is frequently associated with these lesions. In the context of intraamniotic infection, chemokines (such as interleukin-8 and granulocyte chemotactic protein) establish a gradient that favors the migration of neutrophils from the maternal or fetal circulation into the chorioamniotic membranes or umbilical cord, respectively. Danger signals that are released during the course of cellular stress or cell death can also induce the release of neutrophil chemokines. The prevalence of chorioamnionitis is a function of gestational age at birth, and present in 3-5% of term placentas and in 94% of placentas delivered at 21-24 weeks of gestation. The frequency is higher in patients with spontaneous labor, preterm labor, clinical chorioamnionitis (preterm or term), or ruptured membranes. Funisitis and chorionic vasculitis are the hallmarks of the fetal inflammatory response syndrome, a condition characterized by an elevation in the fetal plasma concentration of interleukin-6, and associated with the impending onset of preterm labor, a higher rate of neonatal morbidity (after adjustment for gestational age), and multiorgan fetal involvement. This syndrome is the counterpart of the systemic inflammatory response syndrome in adults: a risk factor for short- and long-term complications (ie, sterile inflammation in fetuses, neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, and cerebral palsy). This article reviews the definition, pathogenesis, grading and staging, and clinical significance of the most common lesions in placental disease. Illustrations of the lesions and diagrams of the mechanisms of disease are provided.