Amniotic fluid infection, inflammation, and colonization in preterm labor with intact membranes

Presence of Streptococcus mutans and interleukin-6 and -10 in amniotic fluid

AIM

To evaluate the presence of Streptococcus mutans (SM), main pathogen of dental caries, interleukin-6 and -10 in samples of amniotic fluid (AF) and clinical and oral data of the healthy pregnancy, to investigate the SM exposition in intrauterine life and to elucidate the presence of antibodies to SM in newborns' saliva (SA) with undetectable levels of this microorganism described in the previous study.

METHODS

The study involved the participation of 26 women with term deliveries and without gestational complications. General health data were collected through a questionnaire applied to the participants. The volunteers were examined orally, the caries experience (decayed, missing, and filled teeth (DMFT) scores) was calculated and unstimulated SA was collected. The acquisition of AF was performed during cesarean sections and stocked on ice. The analysis of the presence of SM-DNA was performed by real-time PCR assays with specific primers. Levels of IL-6 and IL-10 were performed by ELISA with specific kits for these interleukins in the AF samples.

RESULTS

69.2% of the AF samples had detectable SM, and 65% of the women had the bacteria in the AF and SA at the same time. There was a positive association between the presence of SM in AF and a report of not going to the dentist frequently (p<.05). There was no statistically significant difference between the frequency of AF with or without detection of MS and active caries (p>.05). However, the DMFT scores of women with positive AF for SM were higher than that of women without detectable MS (p<.05). IL-6 levels were higher than IL-10 in AF (p<.05). There were no significant differences in the levels of interleukins between samples with detectable SM or in AF and even with clinical data analysis (p>.05).

CONCLUSIONS

The AF samples have SM in quantifiable levels, probably associated with the greatest caries experience, and seen by the highest DMFT index. Interleukin levels were not related to the presence of MS. The presence of SM in AF may explain the mucosal immune stimulation of newborn children by the previous detection of salivary antibodies against SM.

Fetal heart rate variability is a biomarker of rapid but not progressive exacerbation of inflammation in preterm fetal sheep

Perinatal infection/inflammation can trigger preterm birth and contribute to neurodevelopmental disability. There are currently no sensitive, specific methods to identify perinatal infection. We investigated the utility of time, frequency and non-linear measures of fetal heart rate (FHR) variability (FHRV) to identify either progressive or more rapid inflammation. Chronically instrumented preterm fetal sheep were randomly assigned to one of three different 5d continuous i.v. infusions: 1) control (saline infusions; n = 10), 2) progressive lipopolysaccharide (LPS; 200 ng/kg over 24 h, doubled every 24 h for 5d, n = 8), or 3) acute-on-chronic LPS (100 ng/kg over 24 h then 250 ng/kg/24 h for 4d plus 1 μg boluses at 48, 72, and 96 h, n = 9). Both LPS protocols triggered transient increases in multiple measures of FHRV at the onset of infusions. No FHRV or physiological changes occurred from 12 h after starting progressive LPS infusions. LPS boluses during the acute-on-chronic protocol triggered transient hypotension, tachycardia and an initial increase in multiple time and frequency domain measures of FHRV, with an asymmetric FHR pattern of predominant decelerations. Following resolution of hypotension after the second and third LPS boluses, all frequencies of FHRV became suppressed. These data suggest that FHRV may be a useful biomarker of rapid but not progressive preterm infection/inflammation.

Optimization and validation of two multiplex qPCR assays for the rapid detection of microorganisms commonly invading the amniotic cavity

Microbial invasion of the amniotic cavity (MIAC) leading to infection is strongly associated with adverse pregnancy and neonatal outcomes. Limitations of current diagnostic assays to detect MIAC rapidly and accurately have hindered the ability of obstetricians to identify and treat intra-amniotic infections. We developed, optimized, and validated two multiplex quantitative polymerase chain reaction (qPCR) assays for the simultaneous detection and quantification of microbial taxa commonly associated with MIAC. The first assay allows for the quantification of general bacterial and fungal loads in amniotic fluid and includes a human reference gene to allow for assessing the integrity of clinical samples and the DNA extraction process. The second assay allows for the detection and quantification of four specific bacterial taxa commonly associated with MIAC: Ureaplasma spp., Mycoplasma hominis, Streptococcus agalactiae, and Fusobacterium nucleatum. The qPCR assays were validated by using both microbial isolates and clinical amniotic fluid samples. The assays were further validated by comparing qPCR amplification results to those from the microbial culture and bacterial 16S rRNA gene sequencing of amniotic fluid. Both assays demonstrated high reproducibility and are sensitive and specific to their intended targets. Therefore, these assays represent promising molecular diagnostic tools for the detection of MIAC. Most importantly, these assays may allow for administration of timely and targeted antibiotic interventions to reduce adverse perinatal outcomes attributed to intra-amniotic infections.

Armed to the Teeth-The Oral Mucosa Immunity System and Microbiota

The oral cavity is inhabited by a wide spectrum of microbial species, and their colonization is mostly based on commensalism. These microbes are part of the normal oral flora, but there are also opportunistic species that can cause oral and systemic diseases. Although there is a strong exposure to various microorganisms, the oral mucosa reduces the colonization of microorganisms with high rotation and secretion of various types of cytokines and antimicrobial proteins such as defensins. In some circumstances, the imbalance between normal oral flora and pathogenic flora may lead to a change in the ratio of commensalism to parasitism. Healthy oral mucosa has many important functions. Thanks to its integrity, it is impermeable to most microorganisms and constitutes a mechanical barrier against their penetration into tissues. Our study aims to present the role and composition of the oral cavity microbiota as well as defense mechanisms within the oral mucosa which allow for maintaining a balance between such numerous species of microorganisms. We highlight the specific aspects of the oral mucosa protecting barrier and discuss up-to-date information on the immune cell system that ensures microbiota balance. This study presents the latest data on specific tissue stimuli in the regulation of the immune system with particular emphasis on the resistance of the gingival barrier. Despite advances in understanding the mechanisms regulating the balance on the microorganism/host axis, more research is still needed on how the combination of these diverse signals is involved in the regulation of immunity at the oral mucosa barrier.

Chorioamnionitis and neonatal outcomes

Chorioamnionitis or intrauterine inflammation is a frequent cause of preterm birth. Chorioamnionitis can affect almost every organ of the developing fetus. Multiple microbes have been implicated to cause chorioamnionitis, but "sterile" inflammation appears to be more common. Eradication of microorganisms has not been shown to prevent the morbidity and mortality associated with chorioamnionitis as inflammatory mediators account for continued fetal and maternal injury. Mounting evidence now supports the concept that the ensuing neonatal immune dysfunction reflects the effects of inflammation on immune programming during critical developmental windows, leading to chronic inflammatory disorders as well as vulnerability to infection after birth. A better understanding of microbiome alterations and inflammatory dysregulation may help develop better treatment strategies for infants born to mothers with chorioamnionitis.

Protein microarray analysis of amniotic fluid proteins associated with spontaneous preterm birth in women with preterm labor

PROBLEM

To identify proteins present in the amniotic fluid (AF) that could be associated with spontaneous preterm birth (SPTB; delivery < 7 days) in women with preterm labor (PTL).

METHOD OF STUDY

First, the AF proteome of 20 women with PTL and SPTB was compared with that of 20 matched women with term deliveries using an antibody microarray. Next, nine identified candidate biomarkers of SPTB were further validated in 267 singleton pregnant women with PTL who underwent amniocentesis at 26-33 weeks of gestation using ELISA, and whether the degree of expression of these proteins was associated with the risk severity for subsequent SPTB was retrospectively assessed.

RESULTS

Of the 507 proteins evaluated in the microarray analysis, 27 displayed significant intergroup differences. In particular, ELISA quantification confirmed that the expression of EN-RAGE, IL-6, IL-8, IP-10, lipocalin-2, MMP-8, MMP-9, S100 A8/A9, and TNFR2 were all increased in the AF of women spontaneously delivering within 7 days of sampling compared with those delivering after 7 days. Moreover, the odds of SPTB within 7 days, even upon adjusting for confounders, tended to significantly increase with each increasing quartile of baseline AF levels of each protein (P-value for trend < .05).

CONCLUSION

Nine AF proteins were found to be independently associated with higher risk of subsequent SPTB in women with PTL, all of which were immune-, inflammation-, and extracellular matrix-related proteins. Moreover, risk severity for this subsequent SPTB is closely related to the degree of expression of each of these proteins.

Endometrial Microbiome and Women’s Reproductive Health – Review of the Problem Endometrial Microbiome and Reproductive Health

Currently, unlike in the past, the endometrial cavity is not considered to be sterile. The endometrium is supposed to be dominated by Lactobacilli, but also their deficiency can be found in the reproductive tract of asymptomatic healthy women. Sometimes the endometrial microbiome is dominated by various pathological microorganisms, and this can lead to various conditions as chronic endometritis, chorioamnionitis and preterm birth. Their presence causes uterine inflammation and infection, release of pro-inflammatory molecules, uterine contractions, disruption of cervical barrier, premature rupture of membranes. Uterine dysbiosis is associated with recurrent implantation failure and recurrent miscarriages. As the microbiome is important for maintaining immunological homeostasis at the level of gastrointestinal tract Lactobacilli may play a similar function at the level of uterus. The lactobacillus-dominated uterine microbiome is of great importance for maintaining a hostile uterine microenvironment, embryo implantation, early pregnancy development and normal pregnancy outcome.

Bacteria in the amniotic fluid without inflammation: early colonization vs. contamination

OBJECTIVES

Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi.

RESULTS

Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)].

CONCLUSIONS

The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection.

Maternal Plasma and Amniotic Fluid LBP, Pentraxin 3, Resistin, and IGFBP-3: Biomarkers of Microbial Invasion of Amniotic Cavity and/or Intra-amniotic Inflammation in Women with Preterm Premature Rupture of Membranes

BACKGROUND

We sought to determine whether lipopolysaccharide binding protein (LBP), pentraxin 3, resistin, and insulin-like growth factor binding protein (IGFBP)-3 in plasma and amniotic fluid (AF) can predict microbial invasion of the amniotic cavity (MIAC), intra-amniotic inflammation (IAI), and microbial-associated IAI in women with preterm premature rupture of membranes (PPROM).

METHODS

This was a retrospective cohort study involving 168 singleton pregnant women with PPROM. AF obtained via amniocentesis was cultured and assayed for interleukin (IL)-6 to define IAI and for IL-8 to compare with AF biomarkers. Plasma samples were collected at the time of amniocentesis, and C-reactive protein (CRP) levels in serum were compared with plasma biomarkers. The stored plasma and AF samples were assayed for LBP, pentraxin 3 (PTX3), resistin, and IGFBP-3 by ELISA.

RESULTS

Multivariate logistic regression analysis revealed that: 1) elevated plasma and AF levels of LBP were independently associated with increased risks of MIAC, IAI, and microbial-associated IAI; 2) elevated AF, but not plasma, PTX3, and resistin levels were independently associated with increased risks of MIAC, IAI, and microbial-associated IAI; 3) decreased IGFBP-3 levels in the plasma were independently associated with only IAI, whereas those in the AF were associated with only microbial-associated IAI. Among the tested biomarkers, AF PTX3 and resistin had the highest predictive performance for MIAC, IAI, and microbial-associated IAI (area under the curves [AUC] = 0.85-0.95), which is similar to the performance of AF IL-8. The AUCs of the plasma LBP and IGFBP-3 were similar to that of serum CRP with respect to IAI.

CONCLUSION

Maternal plasma LBP and IGFBP-3 are potential biomarkers for the non-invasive identification of IAI in women with PPROM, with a similar accuracy to the serum CRP level. AF LBP, PTX3, resistin, and IGFBP-3 may be involved in the intra-amniotic inflammatory responses in PPROM complicated by MIAC.

The Role of Innate Immune System in the Human Amniotic Membrane and Human Amniotic Fluid in Protection Against Intra-Amniotic Infections and Inflammation

Intra-amniotic infection and inflammation (IAI) affect fetal development and are highly associated with preterm labor and premature rupture of membranes, which often lead to adverse neonatal outcomes. Human amniotic membrane (hAM), the inner part of the amnio-chorionic membrane, protects the embryo/fetus from environmental dangers, including microbial infection. However, weakened amnio-chorionic membrane may be breached or pathogens may enter through a different route, leading to IAI. The hAM and human amniotic fluid (hAF) respond by activation of all components of the innate immune system. This includes changes in 1) hAM structure, 2) presence of immune cells, 3) pattern recognition receptors, 4) cytokines, 5) antimicrobial peptides, 6) lipid derivatives, and 7) complement system. Herein we provide a comprehensive and integrative review of the current understanding of the innate immune response in the hAM and hAF, which will aid in design of novel studies that may lead to breakthroughs in how we perceive the IAI.

Placental pathology: Pathways leading to or associated with perinatal brain injury in experimental neurology, special issue: Placental mediated mechanisms of perinatal brain injury

Perinatal brain injury is a multifactorial process. In utero placental physiology plays a major role in neuroprotection and the normal development of the fetal central nervous system. Advances in placental pathology have clarified several specific mechanisms of injury and the histologic lesions most strongly associated with them. This review provides an updated summary of the relevant placental anatomy and physiology, the specific placental pathways leading to brain injury, the revised Amsterdam classification system for placental pathology, and the known associations of specific placental lesions with subtypes of adverse neurologic outcomes.

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.

Assessment of an intervention to optimise antenatal management of women admitted with preterm labour and intact membranes using amniocentesis-based predictive risk models: study protocol for a randomised controlled trial (OPTIM-PTL Study)

INTRODUCTION

The majority of women admitted with threatened preterm labour (PTL) do not delivery prematurely. While those with microbial invasion of the amniotic cavity (MIAC) represent the highest risk group, this is a condition that is not routinely ruled out since it requires amniocentesis. Identification of low-risk or high-risk cases might allow individualisation of care, that is, reducing overtreatment with corticosteroids and shorten hospital stay in low-risk women, while allowing early antibiotic therapy in those with MIAC. Benefits versus risks of amniocentesis-based predictor models of spontaneous delivery within 7 days and/or MIAC have not been evaluated.

METHODS AND ANALYSIS

This will be a Spanish randomised, multicentre clinical trial in singleton pregnancies (23.0-34.6 weeks) with PTL, conducted in 13 tertiary centres. The intervention arm will consist in the use of amniocentesis-based predictor models: if low risk, hospital discharge within 24 hours of results with no further medication will be recommended. If high risk, antibiotics will be added to standard management. The control group will be managed according to standard institutional protocols, without performing amniocentesis for this indication. The primary outcome will be total antenatal doses of corticosteroids, and secondary outcomes will be days of maternal stay and the occurrence of clinical chorioamnionitis. A cost analysis will be undertaken. To observe a reduction from 90% to 70% in corticosteroid doses, a reduction in 1 day of hospital stay (SD of 2) and a reduction from 24% to 12% of clinical chorioamnionitis, a total of 340 eligible patients randomised 1 to 1 to each study arm is required (power of 80%, with type I error α=0.05 and two-sided test, considering a dropout rate of 20%). Randomisation will be stratified by gestational age and centre.

ETHICS AND DISSEMINATION

Prior to receiving approval from the Ethics Committee (HCB/2020/1356) and the Spanish Agency of Medicines and Medical Devices (AEMPS) (identification number: 2020-005-202-26), the trial was registered in the European Union Drug Regulating Authorities Clinical Trials database (2020-005202-26). AEMPS approved the trial as a low-intervention trial. All participants will be required to provide written informed consent. Findings will be disseminated through workshops, peer-reviewed publications and national/international conferences.

PROTOCOL VERSION

V.4 10 May 2021.

TRIAL REGISTRATION NUMBERS

NCT04831086 and Eudract number 2020-005202-26.

Vaginal microbiome as a tool for prediction of chorioamnionitis in preterm labor: a pilot study

Intra-amniotic infection (IAI) is a major cause of preterm birth with a poor perinatal prognosis. We aimed to determine whether analyzing vaginal microbiota can evaluate the risk of chorioamnionitis (CAM) in preterm labor cases. Vaginal discharge samples were collected from 83 pregnant women admitted for preterm labor. Based on Blanc's classification, the participants were divided into CAM (stage ≥ II; n = 46) and non-CAM (stage ≤ I; n = 37) groups. The 16S rDNA amplicons (V1-V2) from vaginal samples were sequenced and analyzed. Using a random forest algorithm, the bacterial species associated with CAM were identified, and a predictive CAM (PCAM) scoring method was developed. The α diversity was significantly higher in the CAM than in the non-CAM group (P < 0.001). The area under the curve was 0.849 (95% confidence interval 0.765-0.934) using the PCAM score. Among patients at < 35 weeks of gestation, the PCAM group (n = 22) had a significantly shorter extended gestational period than the non-PCAM group (n = 25; P = 0.022). Multivariate analysis revealed a significant difference in the frequency of developmental disorders in 3-year-old infants (PCAM, 28%, non-PCAM, 4%; P = 0.022). Analyzing vaginal microbiota can evaluate the risk of IAI. Future studies should establish appropriate interventions for IAI high-risk patients to improve perinatal prognosis.

Preterm Birth Is Associated With Immune Dysregulation Which Persists in Infants Exposed to Histologic Chorioamnionitis

Introduction

Preterm infants are at increased risk of exposure to histologic chorioamnionitis (HCA) when compared to term-born controls, and this is associated with several neonatal morbidities involving brain, lungs and gut. Preterm infants could benefit from immunomodulatory therapies in the perinatal period, but development of rational treatment strategies requires improved characterization of the perinatal response to HCA. We had two objectives: The first, to characterize the umbilical cord blood immune profile in preterm infants compared to term-born controls; the second, to investigate the postnatal immune response in preterm infants exposed to HCA versus those who were not.

Population

For objective one 59 term infants [mean gestational age (GA) 39⁺⁴ (37⁺³ to 42⁺⁰)] and 55 preterm infants [mean GA29⁺⁰(23⁺³ to 32⁺⁰)] with umbilical cord samples available were included; for objective two we studied 96 preterm infants [mean GA29⁺¹(23⁺² to 32⁺⁰)] for whom placental histology and postnatal blood samples were available.

Methods

Placental histopathology was used to identify reaction patterns indicative of HCA, and a customized immunoassay of 24 inflammatory markers and trophic proteins selected to reflect the perinatal immune response was performed on umbilical cord blood in term and preterm participants and postnatal day 5 blood in the preterm group.

Results

The umbilical cord blood immune profile classified gestational age category with 86% accuracy (95% CI 0.78-0.92), p-value=1.242x10^-14. Pro-inflammatory proteins IL-6, MCP-1 and CRP were elevated in the cord blood of preterm infants whilst BDNF, C3, C9, IL-18, MMP-9 and RANTES were decreased, compared to infants born at term. In preterm infants, exposure to HCA was associated with elevations in 8 immune proteins on postnatal day 5 (BDNF, C3, C5a, C9, IL-8, MCP-1, MIP-1β and MMP-9) when compared to preterm infants who were not exposed.

Conclusion

Preterm birth is associated with a distinct immune profile in umbilical cord blood and preterm infants exposed to HCA with evidence of a fetal inflammatory response have specific alterations in immune function that are apparent on day 5 of postnatal life.

The Distinct Immune Nature of the Fetal Inflammatory Response Syndrome Type I and Type II

Fetal inflammatory response syndrome (FIRS) is strongly associated with neonatal morbidity and mortality and can be classified as type I or type II. Clinically, FIRS type I and type II are considered as distinct syndromes, yet the molecular underpinnings of these fetal inflammatory responses are not well understood because of their low prevalence and the difficulty of postdelivery diagnosis. In this study, we performed RNA sequencing of human cord blood samples from preterm neonates diagnosed with FIRS type I or FIRS type II. We found that FIRS type I was characterized by an upregulation of host immune responses, including neutrophil and monocyte functions, together with a proinflammatory cytokine storm and a downregulation of T cell processes. In contrast, FIRS type II comprised a mild chronic inflammatory response involving perturbation of HLA transcripts, suggestive of fetal semiallograft rejection. Integrating single-cell RNA sequencing-derived signatures with bulk transcriptomic data confirmed that FIRS type I immune responses were mainly driven by monocytes, macrophages, and neutrophils. Last, tissue- and cell-specific signatures derived from the BioGPS Gene Atlas further corroborated the role of myeloid cells originating from the bone marrow in FIRS type I. Collectively, these data provide evidence that FIRS type I and FIRS type II are driven by distinct immune mechanisms; whereas the former involves the innate limb of immunity consistent with host defense, the latter resembles a process of semiallograft rejection. These findings shed light on the fetal immune responses caused by infection or alloreactivity that can lead to deleterious consequences in neonatal life.

The induction of preterm labor in rhesus macaques is determined by the strength of immune response to intrauterine infection

Intrauterine infection/inflammation (IUI) is a major contributor to preterm labor (PTL). However, IUI does not invariably cause PTL. We hypothesized that quantitative and qualitative differences in immune response exist in subjects with or without PTL. To define the triggers for PTL, we developed rhesus macaque models of IUI driven by lipopolysaccharide (LPS) or live Escherichia coli. PTL did not occur in LPS challenged rhesus macaques, while E. coli–infected animals frequently delivered preterm. Although LPS and live E. coli both caused immune cell infiltration, E. coli–infected animals showed higher levels of inflammatory mediators, particularly interleukin 6 (IL-6) and prostaglandins, in the chorioamnion-decidua and amniotic fluid (AF). Neutrophil infiltration in the chorio-decidua was a common feature to both LPS and E. coli. However, neutrophilic infiltration and IL6 and PTGS2 expression in the amnion was specifically induced by live E. coli. RNA sequencing (RNA-seq) analysis of fetal membranes revealed that specific pathways involved in augmentation of inflammation including type I interferon (IFN) response, chemotaxis, sumoylation, and iron homeostasis were up-regulated in the E. coli group compared to the LPS group. Our data suggest that the intensity of the host immune response to IUI may determine susceptibility to PTL.

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

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

The Role of Antimicrobial Peptides in Preterm Birth

Antimicrobial peptides (AMPs) are short cationic amphipathic peptides with a wide range of antimicrobial properties and play an important role in the maintenance of immune homeostasis by modulating immune responses in the reproductive tract. As intra-amniotic infection and microbial dysbiosis emerge as common causes of preterm births (PTBs), a better understanding of the AMPs involved in the development of PTB is essential. The altered expression of AMPs has been reported in PTB-related clinical presentations, such as preterm labor, intra-amniotic infection/inflammation, premature rupture of membranes, and cervical insufficiency. Moreover, it was previously reported that dysregulation of AMPs may affect the pregnancy prognosis. This review aims to describe the expression of AMPs associated with PTBs and to provide new perspectives on the role of AMPs in PTB.

The Inflammatory Milieu of Amniotic Fluid Increases with Chorio-Deciduitis Grade in Inflammation-Restricted to Choriodecidua, but Not Amnionitis, of Extra-Placental Membranes

No information exists about whether intra-amniotic inflammatory response increases with a chorio-deciduitis grade in the context of both inflammation-restricted to chorio-decidua and amnionitis of extra-placental membranes among spontaneous preterm births. The objective of current study is to examine this issue. A study population included 195 singleton pregnant women with chorio-deciduitis, and who spontaneously delivered at preterm (21.6~35.7 weeks) within 7 days of amniocentesis. We examined intra-amniotic inflammatory response according to the chorio-deciduitis grade in the context of inflammation restricted to chorio-decidua and amnionitis of extra-placental membranes. Intra-amniotic inflammatory response was measured by MMP-8 concentration (ng/mL) and WBC-count (cells/mm3) in amniotic-fluid (AF). Inflammation restricted to chorio-decidua and amnionitis were present in 47.7% (93/195) and 52.3% (102/195) of cases, respectively. Median AF MMP-8 concentration and WBC-count significantly increased with chorio-deciduitis grade in the context of inflammation restricted to chorio-decidua. However, there was no significant difference in median AF MMP-8 concentration and WBC-count between chorio-deciduitis grade-1 and grade-2 in the context of amnionitis. The inflammatory milieu of AF increases with chorio-deciduitis grade in inflammation-restricted to chorio-decidua, but not amnionitis, of extra-placental membranes. This finding suggests that a chorio-deciduitis grade may have little effect on the intensification of intra-amniotic inflammatory response in the context of amnionitis of extra-placental membranes.

Daily monitoring of vaginal interleukin 6 as a predictor of intraamniotic inflammation after preterm premature rupture of membranes - a new method of sampling studied in a prospective multicenter trial

OBJECTIVES

(A) To introduce a new technique for vaginal fluid sampling (biocompatible synthetic fiber sponge) and (B) evaluate the collected vaginal fluid interleukine-6 (IL-6_vag)-concentration as a new diagnostic tool for daily monitoring of intrauterine inflammation after preterm premature rupture of membranes (PPROM). Secondary objectives were to compare the potential to predict an intrauterine inflammation with established inflammation parameters (e.g., maternal white blood cell count).

METHODS

This prospective clinical case-control diagnostic accuracy multicenter study was performed with women after PPROM (gestational age 24.0/7 - 34.0/7 weeks). Sampling of vaginal fluid was performed once daily. IL-6_vag was determined by electrochemiluminescence-immunoassay-kit. Neonatal outcome and placental histology results were used to retrospectively allocate the cohort into two subgroups: 1) inflammation and 2) no inflammation (controls).

RESULTS

A total of 37 cases were included in the final analysis. (A): Measurement of IL-6 was successful in 86% of 172 vaginal fluid samples. (B): Median concentration of IL-6_vag in the last vaginal fluid sample before delivery was significantly higher within the inflammation group (17,085 pg/mL) compared to the controls (1,888 pg/mL; p=0.01). By Youden's index an optimal cut-off for prediction an intrauterine inflammation was: 6,417 pg/mL. Two days before delivery, in contrast to all other parameters IL-6_vag remained the only parameter with a sufficient AUC of 0.877, p<0.001, 95%CI [0.670-1.000].

CONCLUSIONS

This study established a new technique for vaginal fluid sampling, which permits assessment of IL-6_vag concentration noninvasively in clinical daily routine monitoring.

Potential Prenatal Origins of Necrotizing Enterocolitis

Necrotizing enterocolitis is a serious and yet incompletely understood gastrointestinal disease of infancy that predominately impacts premature neonates. Prevention is a key strategy for the management of necrotizing enterocolitis. Although postnatal risk factors have been the focus of prevention efforts, obstetric complications, including intrauterine inflammation and infection, growth restriction, preeclampsia, and prenatal medications, have been associated with an increased risk of necrotizing enterocolitis. This article reviews the evidence behind the prenatal risk factors for necrotizing enterocolitis, and discusses how these risk factors may elucidate the pathogenesis of necrotizing enterocolitis and provide insight into prevention and treatment.

A Rapid Amniotic Fluid Interleukin-6 Assessment for the Identification of Intra-Amniotic Inflammation in Women with Preterm Labor and Intact Membranes

OBJECTIVES

A multivariable predictive model has recently been developed with good accuracy to predict spontaneous preterm delivery within 7 days in women with preterm labor (PTL) and intact membranes. However, this model measures amniotic fluid (AF) interleukin (IL)-6 concentrations using the ELISA method, thereby limiting clinical implementation. The main objectives of this study were to validate the automated immunoassay as a quantitative method to measure AF IL-6 in women with PTL and to evaluate the diagnostic performance of AF IL-6 alone and as part of a multivariable predictive model to predict spontaneous delivery in 7 days with this automated method.

STUDY DESIGN

This is a retrospective observational study in women with PTL below 34 weeks who underwent amniocentesis to rule out microbial invasion of the amniotic cavity. Women with clinical signs of chorioamnionitis, cervical length measurement at admission >5th centile, maternal age <18 years, and no consent to perform amniocentesis for this indication were excluded. The local Institutional Review Boards approved the study (HCB/2019/0940). Analysis of AF IL-6 Concentrations: AF IL-6 concentrations were measured using an automated Cobas e602 electrochemiluminescence immunoanalyzer and Human IL-6 Quantikine ELISA kit.

RESULTS

Of the entire study group (n = 100), 38 women spontaneously delivered within 7 days after admission. Both laboratory methods showed good agreement (intraclass correlation coefficient: 0.937 (95% confidence interval [CI] 0.908-0.957); p < 0.001). Diagnostic performance of AF IL-6 to predict spontaneous delivery within 7 days when it was included in the multivariable predictive model showed an area under the receiver operating characteristic curve of 0.894 (95% CI 0.799-0.955), sensitivity of 97%, specificity of 74%, positive predictive value of 73%, negative predictive value of 97%, positive likelihood ratio (LR) of 3.7, and negative LR of 0.045.

CONCLUSION

While both analytical methods were comparable for measuring AF IL-6 concentrations in women with PTL, the Cobas immunoanalyzer provided rapid diagnosis of intra-amniotic inflammation within minutes. The predictive model showed a good diagnostic performance to target women at high risk of spontaneous delivery within 7 days.

RNA Sequencing Reveals Distinct Immune Responses in the Chorioamniotic Membranes of Women with Preterm Labor and Microbial or Sterile Intra-amniotic Inflammation

Preterm labor precedes premature birth, the leading cause of neonatal morbidity and mortality worldwide. Preterm labor can occur in the context of either microbe-associated intra-amniotic inflammation (i.e., intra-amniotic infection) or intra-amniotic inflammation in the absence of detectable microorganisms (i.e., sterile intra-amniotic inflammation). Both intra-amniotic infection and sterile intra-amniotic inflammation trigger local immune responses that have deleterious effects on fetal life. Yet, the extent of such immune responses in the fetal tissues surrounding the amniotic cavity (i.e., the chorioamniotic membranes) is poorly understood. By using RNA sequencing (RNA seq) as a discovery approach, we found that there were significant transcriptomic differences involving host response to pathogens in the chorioamniotic membranes of women with intra-amniotic infection compared to those from women without inflammation. In addition, the sterile or microbial nature of intra-amniotic inflammation was associated with distinct transcriptomic profiles in the chorioamniotic membranes. Moreover, the immune response in the chorioamniotic membranes of women with sterile intra-amniotic inflammation was milder in nature than that induced by microbes and involved the upregulation of alarmins and inflammasome-related molecules. Lastly, the presence of maternal and fetal inflammatory responses in the placenta was associated with the upregulation of immune processes in the chorioamniotic membranes. Collectively, these findings provide insight into the immune responses against microbes or alarmins that take place in the fetal tissues surrounding the amniotic cavity, shedding light on the immunobiology of preterm labor and birth.

Interleukin-6 in Amniotic Fluid: A Reliable Marker for Adverse Outcomes in Women in Preterm Labor and Intact Membranes

INTRODUCTION

Amniotic fluid (AF) interleukin-6 (IL-6) concentration has been associated to preterm delivery and perinatal morbidity and mortality in women with preterm labor and intact membranes. Nevertheless, the clinical significance of this biomarker of intra-amniotic inflammation (IAI) is still unclear due in part to the paucity of large studies.

METHODS

AF IL-6 concentrations were determined in 452 consecutive women with preterm labor and intact membranes, categorized into 3 groups: 302 without IAI (IL-6 of <2.6 ng/mL), 64 with mild IAI (IL-6 of 2.6-11.2 ng/mL), and 86 with severe IAI (IL-6 of ≥11.3 ng/mL).

RESULTS

The severe IAI group had a short pregnancy duration from amniocentesis to delivery (median 3 days) than in without IAI group (median 45 days); meanwhile, the mild IAI group had a latency that was intermediate to the severe and without IAI groups (median 9.5 days). As compared to women without IAI, women with mild and severe IAI had higher rates of preterm delivery at both <34 and <37 weeks of gestation and perinatal morbidity and mortality. Furthermore, the risk of various individual adverse outcomes (short latency from amniocentesis to delivery [at ≤3 days, ≤7 days, and ≤14 days], preterm delivery at both <34 and <37 weeks of gestation, histologic chorioamnionitis, respiratory distress syndrome, and congenital sepsis) was higher in women with severe IAI (OR ≥ 2.8), compared with women without IAI.

CONCLUSIONS

AF IL-6 concentrations appear to be suitable marker to assess the degree of IAI and are associated with increased risk of adverse outcomes.

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care

OBJECTIVES

Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia.

METHODS

This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL.

RESULTS

(1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases.

CONCLUSIONS

Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

The oralome and its dysbiosis: New insights into oral microbiome-host interactions

The oralome is the summary of the dynamic interactions orchestrated between the ecological community of oral microorganisms (comprised of up to approximately 1000 species of bacteria, fungi, viruses, archaea and protozoa - the oral microbiome) that live in the oral cavity and the host. These microorganisms form a complex ecosystem that thrive in the dynamic oral environment in a symbiotic relationship with the human host. However, the microbial composition is significantly affected by interspecies and host-microbial interactions, which in turn, can impact the health and disease status of the host. In this review, we discuss the composition of the oralome and inter-species and host-microbial interactions that take place in the oral cavity and examine how these interactions change from healthy (eubiotic) to disease (dysbiotic) states. We further discuss the dysbiotic signatures associated with periodontitis and caries and their sequalae, (e.g., tooth/bone loss and pulpitis), and the systemic diseases associated with these oral diseases, such as infective endocarditis, atherosclerosis, diabetes, Alzheimer's disease and head and neck/oral cancer. We then discuss current computational techniques to assess dysbiotic oral microbiome changes. Lastly, we discuss current and novel techniques for modulation of the dysbiotic oral microbiome that may help in disease prevention and treatment, including standard hygiene methods, prebiotics, probiotics, use of nano-sized drug delivery systems (nano-DDS), extracellular polymeric matrix (EPM) disruption, and host response modulators.

[Current approach in preterm prelabor rupture of membranes: new definitions? Is CRP determination useful? Are alternatives in sight?]

Around 3% of all pregnancies are complicated by preterm prelabor rupture of membranes (PPROM) before 37 + 0 weeks of gestation. Since PPROM is likely to be associated with microbial invasion of the amniotic cavity (MIAC)-either before or secondary to PPROM-the risk of developing intraamniotic inflammation (IAI) is high. IAI is associated with short latency to delivery and with adverse short- and long-term outcomes for the newborn, especially in cases of fetal inflammatory response syndrome (FIRS). Prediction of IAI based on maternal parameters is difficult or impossible. The recently established definition of triple I ("infection, inflammation, or both") is based on the parameter "maternal body temperature". If this is increased to ≥ 38.0 °C and there is no other reason to explain maternal fever, the finding is suspicious for triple I if at least one other of the following parameters can be found: fetal tachycardia > 160 bpm for at least 10 min, maternal leukocytes > 15,000/µl without administration of corticosteroids, or purulent fluid from the cervical os. Pregnancies suspicious for triple I should be terminated. The confirmation of triple I is only possible by placental histology (histologically confirmed chorioamnionitis, HCA). Confirmation based on amniocentesis (positive Gram stain, low glucose concentration [<14 mg/dl], elevated white blood cell count [>30 cells/mm³], positive culture) takes too long and is unreliable. Serial determinations of C‑reactive protein also do not allow reliable diagnosis of IAI. Studies using interleukin 6 measurements from the posterior fornix and/or cervical os are promising methods, the validation of which is awaited.

MicroRNAs miR-4535 and miR-1915-5p in amniotic fluid as predictive biomarkers for chorioamnionitis

Background:

This study was performed to investigate the clinical significance of miR-4535 and miR-1915-5p in severe chorioamnionitis.

Materials & methods:

Amniotic fluid samples from 37 patients with severe chorioamnionitis were subjected to miRNA array analysis and ddPCR™. Diagnostic values were assessed using the receiver operating characteristic curve. The patients were separated into three groups according to Blanc’s criteria.

Results:

The expression of miR-4535 and miR-1915-5p was significantly correlated with the copy number of 16S rDNA, had extremely high diagnostic accuracy for severe chorioamnionitis, and was linked to maternal and fetal inflammation.

Conclusion:

miR-4535 and miR-1915-5p serve as promising biomarkers for the diagnosis of severe chorioamnionitis.

Chorioamnionitis and fetal inflammatory response syndrome, which is linked to chorioamnionitis, are considered serious diseases in perinatal care. In this study, miR-4535 and miR-1915-5p are recognized as promising biomarkers for the diagnosis of chorioamnionitis before delivery. In particular, the increased expression of miR-4535 in amniotic fluid is expected to be regarded as a positive indicator for fetal inflammatory response syndrome, and the elevated expression of miR-4535 in serum is also considered to predictively diagnose intrauterine infection in pregnancy. Our results highlight that further studies should explore the underlying clinical significance of miR-4535 and miR-1915-5p.

Exploratory and confirmatory analysis to investigate the presence of vaginal metabolome expression of microbial invasion of the amniotic cavity in women with preterm labor using high-performance liquid chromatography

BACKGROUND

Although the influence of microbial invasion of the amniotic cavity on the development of spontaneous preterm delivery is unquestionable, the use of an invasive procedure to diagnose the status of an infection limits its clinical translation.

OBJECTIVE

This study aimed to use exploratory and confirmatory analyses to investigate the presence of vaginal metabolome expression of microbial invasion of the amniotic cavity in women diagnosed as having preterm labor using high-performance liquid chromatography.

STUDY DESIGN

In 140 women with singleton pregnancies and a diagnosis of preterm labor at <34 weeks' gestation, we analyzed vaginal amino acid concentrations using high-performance liquid chromatography. Vaginal samples were collected shortly after the amniocentesis performed at admission to rule out microbial invasion of the amniotic cavity. Data were normalized for the median of all the amino acid concentrations evaluated. Microbial invasion of the amniotic cavity was defined as a positive aerobic or anaerobic amniotic fluid culture for the presence of bacteria or yeast or Ureaplasma species or Mycoplasma hominis in the mycoplasma culture or a positive polymerase chain reaction result for 16S rRNA gene sequence. Exploratory analysis was performed in half of the sample and confirmatory analysis in the other half. We compared vaginal amino acid concentrations between women with and without microbial invasion of the amniotic cavity in both cohorts. The area under the curve with 95% confidence interval values were calculated for vaginal amino acids with significant differences.

RESULTS

In the exploratory cohort (2014-2015), 17 of 76 women (22.3%) had microbial invasion of the amniotic cavity compared with 14 of 72 (19.4%) in the confirmatory cohort (2016-2017). In the exploratory cohort, we found significantly higher amino acid concentrations of vaginal taurine, lysine, and cysteine and significantly lower concentrations of vaginal glutamate, aspartate, and the aspartate to asparagine ratio. These significant differences were confirmed in the confirmatory cohort. The area under the curve of these vaginal amino acids to predict microbial invasion of the amniotic cavity ranged between 0.72 and 0.79, with cysteine being the amino acid with the best performance with an area under the curve of 0.79 (95% confidence interval, 0.71-0.88).

CONCLUSION

We found the vaginal metabolome expression of microbial invasion of the amniotic cavity in women with preterm labor and intact membranes. These findings might open the possibility to develop noninvasive diagnostic tools of microbial invasion of the amniotic cavity with the aim of selecting women who would most likely benefit from an amniocentesis for this indication.

A protein microarray analysis of amniotic fluid proteins for the prediction of spontaneous preterm delivery in women with preterm premature rupture of membranes at 23 to 30 weeks of gestation

Objective

We sought to identify novel biomarkers in the amniotic fluid (AF) related to imminent spontaneous preterm delivery (SPTD) (≤ 14 days after sampling) in women with early preterm premature rupture of membranes (PPROM), using a protein microarray.

Method

This was a retrospective cohort study of a total of 88 singleton pregnant women with PPROM (23+0 to 30+6 weeks) who underwent amniocentesis. A nested case-control study for biomarker discovery was conducted using pooled AF samples from controls (non-imminent delivery, n = 15) and cases (imminent SPTD, n = 15), which were analyzed using an antibody microarray. Quantitative validation of four candidate proteins was performed, using ELISA, in the total cohort (n = 88). IL-8, MMP-9, and Fas levels were additionally measured for the comparison and to examine association of SPTD with the etiologic factors of PPROM.

Results

Of all the proteins studied in the protein microarray, four showed significant intergroup differences. Analyses of the total cohort by ELISA confirmed the significantly elevated concentrations of AF lipocalin-2, MMP-9, and S100 A8/A9, but not of endostatin and Fas, in women who delivered within 14 days of sampling. For inflammatory proteins showing a significant association, the odds of SPTD within 14 days increased significantly with an increase in baseline AF levels of the proteins (P for trend <0.05 for each) in each quartile, especially in the 3rd and 4th quartile.

Conclusions

We identified several potential novel biomarkers (i.e., lipocalin-2, MMP-9, and S100 A8/A9) related to SPTD within 14 days of sampling, all of which are inflammation-related molecules. Furthermore, the SPTD risk increased with increasing quartiles of each of these inflammatory proteins, especially the 3rd and 4th quartile of each protein. The present findings may highlight the importance of inflammatory mechanisms and the degree of activated inflammatory response in developing SPTD in early PPROM.

Porphyromonas gingivalis Placental Atopobiosis and Inflammatory Responses in Women With Adverse Pregnancy Outcomes

The microbiome modulates inflammation at the fetal maternal interface on both term and preterm labor. Inflammophilic oral bacteria, such as Porphyromonas gingivalis, as well as urogenital microorganisms (UGM) could translocate to the placenta and activate immune mechanisms in decidual tissue that is associated with adverse pregnancy outcomes (APO). This study establishes the associations between the presence of microbes in the placenta and placental cytokine patterns in women who presented APO, e.g., low birth weight (LBW), preterm premature rupture of membranes (PPROM), preterm birth (PTB) and other clinical signs related to Chorioamnionitis (CA). A total of 40 pregnant women were included in the study and divided into five groups according to placental infection (PI) and APO, as follows: (1) women without PI and without APO (n = 17), (2) women with P. gingivalis-related PI and APO (n = 5), (3) women with P. gingivalis-related PI and without APO (n = 4), (4) women with PI related to UGM and APO (n = 5) and (5) women without PI with APO (n = 9). Obstetric, clinical periodontal status evaluation, and subgingival plaque sampling were performed at the time of delivery. Placental levels of interleukin IL-1β, IL-6, IL-10, IL-15, IL-17A, IL-17F, IL-21, IL-12p70, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 α (MCP-1α), granzyme B, and interferon-γ (IFN-γ) were determined using a multiplex flow cytometry assay. All patients showed a predominant Th-1 cytokine profile related to labor, characterized by IFN-γ overexpression. The analysis by groups suggests that Th-1 profile was trending to maintain cytotoxic cell activity by the expression of IL-15 and granzyme B, except for the group with P. gingivalis-related PI and APO, which exhibited a reduction of IL-10 and IL-17F cytokines (p < 0.05) and a Th-1 profile favoring macrophage activation by MCP-1 production (p < 0.05). This study confirms a pro-inflammatory pattern associated with labor, characterized by a Th-1 profile and the activity of cytotoxic cells, which is enhanced by PI with UGM. However, PI associated with P. gingivalis suggests a switch where the Th-1 profile favors an inflammatory response mediated by MCP-1 and macrophage activity as a mechanistic explanation of its possible relationship with adverse outcomes in pregnancy.

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.

Prostaglandin and prostamide concentrations in amniotic fluid of women with spontaneous labor at term with and without clinical chorioamnionitis

OBJECTIVE

Prostaglandins (PGs) are considered universal mediators for the process of physiological parturition. This is based on observations that amniotic fluid concentrations of PGs are elevated prior to and during the onset of labor (mostly utilizing immunoassays). Distinguishing PGs from similarly structured molecules (i.e. prostamides; PG-EA) is difficult given the cross-reactivity of available antibodies and the chemical similarity between these compounds. Herein, this limitation was overcome by utilizing mass spectrometry to determine PG and PG-EA concentrations in amniotic fluid of women with spontaneous labor at term and in those with clinical chorioamnionitis (CHAM), the most common infection-related diagnosis made in labor and delivery units worldwide.

STUDY DESIGN

Liquid chromatography-tandem mass spectrometry (LC MS/MS) was used to determine the PG and PG-EA content in amniotic fluid samples of women with spontaneous labor at term with (n = 14) or without (n = 28) CHAM. Controls included women who delivered at term without labor (n = 10).

RESULTS

PGE_2, PGF_2α, and 13,14-dihydro-15-keto-PGF_2α (PGFM) were higher in amniotic fluid of women with spontaneous labor at term than in those without labor. PGE₂, PGF_2α, and PGFM were also higher in amniotic fluid of women with CHAM than in those without labor. However, PGE₂-EA and PGF_2α-EA were lower in amniotic fluid of women with CHAM than in those without CHAM. The ratios of PGE₂ to PGE₂-EA and PGF_2α to PGF_2α-EA were higher in amniotic fluid of women with spontaneous labor at term with or without CHAM than in those without labor; yet, the ratio of PGF_2α to PGF_2α-EA was greater in women with CHAM than in those without this clinical condition.

CONCLUSIONS

Spontaneous labor at term with or without CHAM is characterized by elevated amniotic fluid concentrations of prostaglandins (PGE₂, PGF_2α, and PGFM) but not prostamides. Quantification of these products by LC MS/MSlc==may potentially be of utility in identifying their physiological functions relevant to parturition.

SUMMARY

Prostaglandins (PGs) are critical for the onset and progression of labor. Structural similarities of PGs and prostamides (PG-EA) prevents their specific identification by immunoassay. We utilized LC MS/MS to determine PG and PG-EA content in amniotic fluid (AF) of women with spontaneous labor at term with or without CHAM and women who delivered at term without labor. Higher aamniotic ffluid PG levels were observed in women with spontaneous labor with and without CHAM compared to women delivering without labor. PG-EA levels in amniotic fluid of women with spontaneous labor and CHAM were lower than in women with spontaneous labor without CHAM but not those without labor. Ratios of PGs to PG-EAs were higher in AF of women with labor and CHAM compared to those without labor. Delineation of these products by LC MS/MS may potentially be of utility in identifying their physiological functions relevant to parturition.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

Identifying potential biomarkers related to pre-term delivery by proteomic analysis of amniotic fluid

We sought to identify biomarkers in the amniotic fluid (AF) and specific signaling pathways related to spontaneous preterm delivery (SPTD, < 34 weeks) in women with preterm labor (PTL) without intra-uterine infection/inflammation (IUI). This was a retrospective cohort study of a total of 139 PTL women with singleton gestation (24 + 0 to 32 + 6 weeks) who underwent amniocentesis and who displayed no evidence of IUI. A nested case-control was conducted using pooled AF samples (n = 20) analyzed via label-free liquid chromatography-tandem mass spectrometry. In the total cohort, an ELISA validation study was performed for seven candidate proteins of interest. Proteomic analysis identified 77 differentially expressed proteins (DEPs, P < 0.05) in the AF from SPTD cases compared to term delivery controls. ELISA validation confirmed that women who had an SPTD before 34 weeks had significantly independently lower levels of VEGFR-1 and higher levels of lipocalin-2 and the Fc fragment of IgG binding protein in the AF. Five principle pathways associated with the 77 DEPs were identified, including glycolysis, gluconeogenesis, and iron homeostasis. The proteomic analysis data of AFs from women with PTL identified several novel biomarkers and specific protein pathways related to SPTD in the absence of IUI.

Antibody microarray analysis of amniotic fluid proteins associated with subsequent ruptured membranes in women with threatened preterm labor

PROBLEM

We aimed to identify amniotic fluid (AF) proteins associated with the subsequent rupture of membranes (ROM) occurring in the absence of active labor in women with threatened preterm labor (PTL) using an antibody microarray.

METHOD OF THE STUDY

This retrospective cohort study included 183 singleton pregnant women with PTL (24-33 weeks) who underwent amniocentesis. A nested case-control study was conducted using AF samples from 20 women with subsequent ROM within 7 days of sampling (case subjects) and 20 gestational age-matched women with term delivery (TD) without ROM (control subjects), via protein-antibody microarray analysis. Seven candidate proteins of interest were validated via ELISA in the total cohort.

RESULTS

Seventeen proteins displayed significant intergroup differences. ELISA validation confirmed that the levels of EN-RAGE, Fas, IL-8, IP-10, MMP-8, and MMP-9 were significantly higher, whereas IGFBP-3 levels were significantly lower in the AF of women with subsequent ROM within 7 days of sampling than in that of women with TD without ROM. Moreover, the time interval from sampling to membrane rupture was significantly correlated with the expression levels of AF proteins, except for IL-10.

CONCLUSION

Using an antibody microarray, we identified various inflammatory, angiogenic, matrix-degrading, and apoptosis-related proteins in the AF that were associated with subsequent ROM occurring in the absence of active labor in women with threatened PTL. These findings provide novel insights into the molecular mechanisms underlying membrane rupture without active labor in threatened PTL.

RNA Sequencing Reveals Diverse Functions of Amniotic Fluid Neutrophils and Monocytes/Macrophages in Intra-Amniotic Infection

Intra-amniotic infection, the invasion of microbes into the amniotic cavity resulting in inflammation, is a clinical condition that can lead to adverse pregnancy outcomes for the mother and fetus as well as severe long-term neonatal morbidities. Despite much research focused on the consequences of intra-amniotic infection, there remains little knowledge about the innate immune cells that respond to invading microbes. We performed RNA-seq of sorted amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection to determine the transcriptomic differences between these innate immune cells. Further, we sought to identify specific transcriptomic pathways that were significantly altered by the maternal or fetal origin of amniotic fluid neutrophils and monocytes/macrophages, the presence of a severe fetal inflammatory response, and pregnancy outcome (i.e., preterm or term delivery). We show that significant transcriptomic differences exist between amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection, indicating the distinct roles these cells play. The transcriptome of amniotic fluid immune cells varies based on their maternal or fetal origin, and the significant transcriptomic differences between fetal and maternal monocytes/macrophages imply that those of fetal origin exhibit impaired functions. Notably, transcriptomic changes in amniotic fluid monocytes/macrophages suggest that these immune cells collaborate with neutrophils in the trafficking of fetal leukocytes throughout the umbilical cord (i.e., funisitis). Finally, amniotic fluid neutrophils and monocytes/macrophages from preterm deliveries display enhanced transcriptional activity compared to those from term deliveries, highlighting the protective role of these cells during this vulnerable period. Collectively, these findings demonstrate the underlying complexity of local innate immune responses in women with intra-amniotic infection and provide new insights into the functions of neutrophils and monocytes/macrophages in the amniotic cavity.

Comprehensive proteomic investigation of infectious and inflammatory changes in late preterm prelabour rupture of membranes

Preterm prelabour rupture of membranes beyond the 34th week of gestation (late PPROM) is frequently associated with the risk of the microbial invasion of the amniotic fluid (MIAC) and histological chorioamnionitis (HCA). Hence, we employed a Tandem Mass Tag-based approach to uncover amniotic fluid proteome response to the presence of MIAC and HCA in late PPROM. Protein dysregulation was associated with only five cases in the group of 15 women with confirmed MIAC and HCA. Altogether, 138 amniotic fluid proteins were changed in these five cases exclusively. These proteins were particularly associated with excessive neutrophil responses to infection, such as neutrophil degranulation and extracellular trap formation. We believe that the quantification of these proteins in amniotic fluid may assist in revealing women with the highest risk of excessive inflammatory response in late PPROM.

Protein Concentrations of Thrombospondin-1, MIP-1β, and S100A8 Suggest the Reflection of a Pregnancy Clock in Mid-Trimester Amniotic Fluid

The development of immunoassays enables more sophisticated studies of the associations between protein concentrations and pregnancy outcomes, allowing early biomarker identification that can improve neonatal outcomes. The aim of this study was to explore associations between selected mid-trimester amniotic fluid proteins and (1) overall gestational duration and (2) spontaneous preterm delivery. A prospective cohort study, including women undergoing mid-trimester transabdominal genetic amniocentesis, was performed in Gothenburg, Sweden, 2008-2016 (n = 1072). A panel of 27 proteins related to inflammation was analyzed using Meso-Scale multiplex technology. Concentrations were adjusted for gestational age at sampling, experimental factors, year of sampling, and covariates (maternal age at sampling, parity (nulliparous/multiparous), smoking at first prenatal visit, and in vitro fertilization). Cox regression analysis of the entire cohort was performed to explore possible associations between protein concentrations and gestational duration. This was followed by Cox regression analysis censored at 259 days or longer, to investigate whether associations were detectable in women with spontaneous preterm delivery (n = 47). Finally, linear regression models were performed to analyze associations between protein concentrations and gestational duration in women with spontaneous onset of labor at term (n = 784). HMG-1, IGFBP-1, IL-18, MIP-1α, MIP-1β, S100A8, and thrombospondin-1 were significantly associated with gestational duration at term, but not preterm. Increased concentrations of thrombospondin-1, MIP-1β, and S100A8, respectively, were significantly associated with decreased gestational duration after the Holm-Bonferroni correction in women with spontaneous onset of labor at term. This adds to the concept of a pregnancy clock, where our findings suggest that such a clock is also reflected in the amniotic fluid at early mid-trimester, but further research is needed to confirm this.

Do patients with a short cervix, with or without an ultrasound-indicated cerclage, have an increased risk for a small for gestational age newborn?

INTRODUCTION

Mothers with a short cervix have been shown to have increased risk of spontaneous preterm delivery (PTD) and newborn morbidity. Those who require an ultrasound-indicated cerclage experience the highest rates of morbidity. Inflammation has been linked to a short cervix, and it has been linked to pregnancies affected by small for gestational age (SGA) newborns. To date, there are no studies that have investigated an association between a short cervix, with or without an ultrasound-indicated cerclage, and a SGA newborn.

METHODS

This was a case-control study examining all pregnancies with a transvaginal cervical length <25 mm found at their second trimester anatomy scan. Cases were subdivided into those who received an ultrasound-indicated cerclage (Group 1, n = 52) and those who did not (Group 2, n = 139). Controls were defined as pregnancies with a transvaginal cervical length >25 mm with no cerclage (Group 3, n = 186) whose due date was within 2 months of the case pregnancy. Each short cervix case was matched with a control from group 3 in a 1:1 ratio. The primary outcome was birthweight <10% (SGA). Unadjusted data was analyzed with simple odds ratios. A logistic regression was used to control for confounding variables and provide an adjusted odds ratios (aOR).

RESULTS

The incidence of SGA among cases overall (group 1 + group 2) was 13.6% (26/191). In group 3, the SGA incidence was 4.3% (8/186). The adjusted odds ratio (aOR) for a SGA infant was significant, 2.8 (95% CI 1.2, 6.6). Subgroup analysis showed that Group 1 had an increased risk for an SGA infant [aOR 4.9 (95% CI 1.8, 13.7)], but Group 2 did not show a significant finding [aOR 2.3 (95% CI 0.9, 5.7)].

CONCLUSION

Pregnancies complicated by a short cervical length <25mm, with or without a cerclage, were associated with an increased risk for a SGA newborn. Most of this significance was due to the pregnancies which received an ultrasound-indicated cerclage for a mid-trimester short cervix.

The pivotal roles of the NOD-like receptors with a PYD domain, NLRPs, in oocytes and early embryo development†

Nucleotide-binding oligomerization domain (NOD)-like receptors with a pyrin domain (PYD), NLRPs, are pattern recognition receptors, well recognized for their important roles in innate immunity and apoptosis. However, several NLRPs have received attention for their new, specialized roles as maternally contributed genes important in reproduction and embryo development. Several NLRPs have been shown to be specifically expressed in oocytes and preimplantation embryos. Interestingly, and in line with divergent functions, NLRP genes reveal a complex evolutionary divergence. The most pronounced difference is the human-specific NLRP7 gene, not identified in rodents. However, mouse models have been extensively used to study maternally contributed NLRPs. The NLRP2 and NLRP5 proteins are components of the subcortical maternal complex (SCMC), which was recently identified as essential for mouse preimplantation development. The SCMC integrates multiple proteins, including KHDC3L, NLRP5, TLE6, OOEP, NLRP2, and PADI6. The NLRP5 (also known as MATER) has been extensively studied. In humans, inactivating variants in specific NLRP genes in the mother are associated with distinct phenotypes in the offspring, such as biparental hydatidiform moles (BiHMs) and preterm birth. Maternal-effect recessive mutations in KHDC3L and NLRP5 (and NLRP7) are associated with reduced reproductive outcomes, BiHM, and broad multilocus imprinting perturbations. The precise mechanisms of NLRPs are unknown, but research strongly indicates their pivotal roles in the establishment of genomic imprints and post-zygotic methylation maintenance, among other processes. Challenges for the future include translations of findings from the mouse model into human contexts and implementation in therapies and clinical fertility management.

Development and validation of a multivariable prediction model of spontaneous preterm delivery and microbial invasion of the amniotic cavity in women with preterm labor

BACKGROUND

Early spontaneous preterm delivery is often associated with microbial invasion of the amniotic cavity and/or intraamniotic inflammation.

OBJECTIVE

The objective of the study was to develop and validate clinically feasible multivariable prediction models of spontaneous delivery within 7 days and microbial invasion of the amniotic cavity in women admitted with diagnose of preterm labor and intact membranes below 34 weeks.

STUDY DESIGN

We used data from a cohort of women admitted from 2012 to 2018 with diagnosis of preterm labor below 34 weeks who had undergone amniocentesis to rule out microbial invasion of the amniotic cavity. The main outcome was spontaneous delivery within 7 days from admission. The secondary outcome was microbial invasion of the amniotic cavity, defined by a positive culture and/or 16S ribosomal RNA gene in the amniotic fluid. The sample (n = 358) was divided into derivation (2012-2016) and validation cohorts (2017-2018). Logistic regression models using a stepwise selection of variables were developed for the outcomes evaluated. We explored as predictive variables ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, amniotic fluid glucose, and interleukin-6 (expressed as log units). Models were developed in the derivation cohort and applied to the validation cohort and diagnostic performance was calculated.

RESULTS

The derivation cohort included 263 women and the validation cohort 95 women. One hundred five of the women (39%, 105 of 268) spontaneously delivered in the following 7 days and 68 (19%, 68 of 358) had microbial invasion of the amniotic cavity. For spontaneous delivery within 7 days after admission, 4 predictors were identified: cervical length at admission, gestational age, amniotic fluid glucose, and interleukin-6. The diagnostic performance of the model was assessed in the validation cohort using the receiver operating characteristic curve and showed an area under curve of 0.86 (95% confidence interval, 0.77-0.95) with a detection rate of spontaneous delivery within 7 days of 87%, a false-positive rate of 33%, a negative predictive value of 80%, and a negative likelihood ratio of 0.1908. For microbial invasion of the amniotic cavity, 2 independent predictors of the amniotic cavity were identified: amniotic fluid glucose and maternal C-reactive protein. The receiver operating characteristic curve and an area under curve in the validation cohort was 0.83 (95% confidence interval, 0.70-0.96) with a detection rate of 76%, a false-positive rate of 8%, a negative predictive value of 93%, and a negative likelihood ratio of 0.2591.

CONCLUSION

In women with preterm labor, we propose 2 clinically feasible prediction models to classify as low vs high risk of spontaneous delivery within 7 days and of microbial invasion of the amniotic cavity. The models showed a high diagnostic performance and could be of value to optimize clinical management.

Successful treatment of severe intra-amniotic inflammation and cervical insufficiency with continuous transabdominal amnioinfusion and cerclage: A case report

Severe intra-amniotic inflammation, even with a negative bacterial culture, can lead to premature labor. We report a 43-year-old multiparous woman with severe intra-amniotic inflammation and cervical insufficiency at 23 weeks and 5 days of gestation. Continuous transabdominal amnioinfusion was started 2 days after the diagnosis. The amniotic fluid interleukin-6 level normalized after 2 days of treatment. She underwent Shirodkar cervical cerclage on day 7. Despite termination of amnioinfusion and catheter removal on day 16, the pregnancy was maintained without any subsequent treatment. At 33 weeks and 5 days of gestation, an intrauterine Ureaplasma parvum infection and the onset of contractions led to repeat cesarean delivery. The birth weight was 2292 g, and the Apgar scores were 8/8. Both mother and infant had good outcomes. Continuous transabdominal amnioinfusion may have eliminated factors causing intra-amniotic inflammation, thereby prolonging the pregnancy and improving the infant's prognosis.

Inhibition of the NLRP3 inflammasome can prevent sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes†

Sterile intra-amniotic inflammation is commonly observed in patients with spontaneous preterm labor, a syndrome that commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. However, the mechanisms leading to sterile intra-amniotic inflammation are poorly understood and no treatment exists for this clinical condition. Herein, we investigated whether the alarmin S100B could induce sterile intra-amniotic inflammation by activating the NLRP3 inflammasome, and whether the inhibition of this pathway could prevent preterm labor/birth and adverse neonatal outcomes. We found that the ultrasound-guided intra-amniotic administration of S100B induced a 50% rate of preterm labor/birth and a high rate of neonatal mortality (59.7%) without altering the fetal and placental weights. Using a multiplex cytokine array and immunoblotting, we reported that S100B caused a proinflammatory response in the amniotic cavity and induced the activation of the NLRP3 inflammasome in the fetal membranes, indicated by the upregulation of the NLRP3 protein and increased release of active caspase-1 and mature IL-1β. Inhibition of the NLRP3 inflammasome via the specific inhibitor MCC950 prevented preterm labor/birth by 35.7% and reduced neonatal mortality by 26.7%. Yet, inhibition of the NLRP3 inflammasome at term did not drastically obstruct the physiological process of parturition. In conclusion, the data presented herein indicate that the alarmin S100B can induce sterile intra-amniotic inflammation, preterm labor/birth, and adverse neonatal outcomes by activating the NLRP3 inflammasome, which can be prevented by inhibiting such a pathway. These findings provide evidence that sterile intra-amniotic inflammation could be treated by targeting the NLRP3 inflammasome.

Bacterial Colonization within the First Six Weeks of Life and Pulmonary Outcome in Preterm Infants <1000 g

Bronchopulmonary dysplasia (BPD) is a multifactorial disease mainly provoked by pre- and postnatal infections, mechanical ventilation, and oxygen toxicity. In severely affected premature infants requiring mechanical ventilation, association of bacterial colonization of the lung and BPD was recently disclosed. To analyze the impact of bacterial colonization of the upper airway and gastrointestinal tract on moderate/severe BPD, we retrospectively analyzed nasopharyngeal and anal swabs taken weekly during the first 6 weeks of life at a single center in n = 102 preterm infants <1000 g. Colonization mostly occurred between weeks 2 and 6 and displayed a high diversity requiring categorization. Analyses of deviance considering all relevant confounders revealed statistical significance solely for upper airway colonization with bacteria with pathogenic potential and moderate/severe BPD (p = 0.0043) while no link could be established to the Gram response or the gastrointestinal tract. Our data highlight that specific colonization of the upper airway poses a risk to the immature lung. These data are not surprising taking into account the tremendous impact of microbial axes on health and disease across ages. We suggest that studies on upper airway colonization using predefined categories represent a feasible approach to investigate the impact on the pulmonary outcome in ventilated and non-ventilated preterm infants.

Regulatory T Cells Play a Role in a Subset of Idiopathic Preterm Labor/Birth and Adverse Neonatal Outcomes

Regulatory T cells (Tregs) have been exhaustively investigated during early pregnancy; however, their role later in gestation is poorly understood. Herein, we report that functional Tregs are reduced at the maternal-fetal interface in a subset of women with idiopathic preterm labor/birth, which is accompanied by a concomitant increase in Tc17 cells. In mice, depletion of functional Tregs during late gestation induces preterm birth and adverse neonatal outcomes, which are rescued by the adoptive transfer of such cells. Treg depletion does not alter obstetrical parameters in the mother, yet it increases susceptibility to endotoxin-induced preterm birth. The mechanisms whereby depletion of Tregs induces adverse perinatal outcomes involve tissue-specific immune responses and mild systemic maternal inflammation, together with dysregulation of developmental and cellular processes in the placenta, in the absence of intra-amniotic inflammation. These findings provide mechanistic evidence supporting a role for Tregs in the pathophysiology of idiopathic preterm labor/birth and adverse neonatal outcomes.

CXCL12 in normal and pathological pregnancies: A review

The survival of allogeneic fetuses during pregnancy is a rather paradoxical phenomenon with a complex mechanism. Chemokine ligand12 (CXCL12) and its receptors CXC chemokine receptor (CXCR)4 and 7 are extensively found in placenta tissues and cells, including trophoblast cells, vascular endothelial cells, and decidual stromal and decidual immune cells (eg, NK cells and regulatory T cells). Evidence has illustrated that the CXClL12/CXCR4/CXCR7 axis could enhance the cross talk at the maternal-fetal interface through multiple processes, such as invasion and placental angiogenesis, which appears to be critical signaling components in placentation and fetal outcome. In addition, an increasing number of studies have demonstrated that the CXCL12/CXCR4/CXCR7 axis also stands out for its pleiotropic roles in several pregnancy-associated diseases (eg, recurrent spontaneous abortion (RSA), pre-eclampsia (PE), and preterm labor). In the present review, the different biological properties and signaling in physiological and pathological pregnancy conditions of CXCL12/CXCR4/CXCR7 axis were discussed, with the aim of obtaining a further understanding of the regulatory mechanisms and highlighting their potential as a target for therapeutic approaches.

Genital Micro-Organisms in Pregnancy

The microbiome of the female genital tract may undergo changes in pregnancy due to metabolic, endocrinological, and immunological alterations. These dysbiotic states may cause infections which may ascend upwards to the feto-placental unit or may be seeded hematogenously. These low grade and often low virulent infectious states lead to chronic inflammatory states and maybe associated with adverse maternal and neonatal outcome. Organisms have been isolated from amniotic fluid and placentae from women delivering pre-term; however the possibility of contamination cannot be conclusively ruled out. Common vaginal dysbiotic states often cause symptoms that are overlooked and often untreated. Vulvovaginal Candidiasis (VVC), Bacterial Vaginosis (BV), and Trichomonas Vaginitis (TV) are the commonly occurring dysbiotic states leading to vaginal infective states in pregnancy. With the advent of novel technologies like Next Generation sequencing (NGS), it will soon be possible to comprehensively map the vaginal microbiome and assess the interplay of each microbial state with their effects in pregnancy. This may open new avenues for antibiotic recommendations, probiotics and potential alternate therapies for dysbiotic states leading to pregnancy complications.