Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes

Quantitative cervicovaginal fluid fetal fibronectin: A liquid biopsy for intra-amniotic inflammation

INTRODUCTION

Intra-amniotic inflammation is causally linked to spontaneous preterm labor. The gold standard for the diagnosis of intra-amniotic inflammation is the determination of an amniotic fluid profile obtained from transabdominal amniocentesis, which is invasive. Cervicovaginal fluid fetal fibronectin (fFN) is a widely-used predictive biomarker for spontaneous preterm labor. The aims of this study are to determine (1) whether a quantitative cervicovaginal fluid fFN test can be used to identify the presence of intra-amniotic inflammation; and (2) an appropriate cut-off value of a cervicovaginal fluid fFN concentration for the identification of intra-amniotic inflammation.

MATERIAL AND METHODS

This prospective cohort study included 78 patients with preterm labor and intact membranes who had a sample collected for quantitative cervicovaginal fluid fFN measurement and underwent transabdominal amniocentesis. Intra-amniotic inflammation was defined as an amniotic fluid interleukin-6 concentration ≥2.6 ng/mL. Clinicians were masked from the results of cervicovaginal fluid fFN and amniotic fluid interleukin-6 concentrations. Logistic regression analysis was used to determine which factors were significant predictors of intra-amniotic inflammation. The diagnostic indices of the cervicovaginal fluid fFN test for the identification of intra-amniotic inflammation were calculated.

RESULTS

(1) Frequency of intra-amniotic inflammation was 26.9% (21/78); (2) the higher the cervicovaginal fluid fFN concentration, the greater the risk of intra-amniotic inflammation (p < 0.001); (3) cervicovaginal fluid fFN concentration ≥125 ng/mL had an area under the curve of 0.91 (95% confidence interval: 0.83-0.96) for the identification of intra-amniotic inflammation with 100% sensitivity, 100% negative predictive value, 82.46% specificity and a positive likelihood ratio of 5.7; and (4) cervicovaginal fluid fFN cut-off of 125 ng/mL had a significant higher predictive performance than the traditional cut-off (50 ng/mL) for the identification of intra-amniotic inflammation.

CONCLUSIONS

Quantitative cervicovaginal fluid fFN with a cut-off of 125 ng/mL had a high sensitivity and a negative predictive value as well as a positive likelihood ratio for the identification of intra-amniotic inflammation. Its high sensitivity and negative predictive value can be used to decrease an index of suspicion of intra-amniotic inflammation. This test may be useful as an initial assessment test to select appropriate patients for amniocentesis to determine intra-amniotic inflammation.

Early Biomarkers in the Prediction of Later Functional Impairment in Preterm Children With Cerebral Palsy

BACKGROUND

To identify early biomarkers that could predict later functional capabilities in preterm children with later cerebral palsy (CP).

METHODS

Data from 968 preterm children with later CP were extracted from the Canadian Cerebral Palsy Registry. One hundred eighty-two infants were born before 27 weeks of gestation, 461 infants were born between 27 and 33 weeks, and 325 infants were born between 34 and 37 weeks. Univariate and chi-square analyses were conducted to measure the association between early objective biomarkers and later mobility status defined as Gross Motor Function Classification System (GMFCS) levels IV and V as well as tube feeding dependence.

RESULTS

Univariate analysis suggested no significant association between GMFCS levels IV and V or impaired feeding status and bilateral white matter injury on magnetic resonance imaging, high-grade intraventricular hemorrhage on head ultrasound, chorioamnionitis, a birth weight of 1000 to 1500 g or <1000 g, as well as an Apgar score of ≤5 at five minutes of life. Similar results were found for gestational age <28 weeks at birth. Only a significant association between GMFCS levels IV and V and a cord or first hour of life pH of ≤7 was reported (mobility status: odds ratio [OR] 1.95, 95% confidence interval [CI] 1.09 to 3.57) and feeding status: OR 2.23, CI 0.97 to 4.65)].

CONCLUSIONS

Prediction of functional outcomes based on specific early biomarkers appears hard to obtain in children with CP born preterm in contrast to those born at term. The complications and causal pathways inherent to prematurity may contribute to making prognostication less determinant.

Diagnostic tests for the prediction of histological chorioamnionitis and funisitis in pregnant women with preterm premature rupture of membranes: A systematic review

BACKGROUND

Infection of the amniotic cavity is an important driver and/or consequence of preterm prelabour rupture of membranes (PPROM). Prediction of infection is challenging, limiting guidance for interventions during the antenatal period. Infection typically triggers a host inflammatory response, and non-invasive indirect markers of the maternal or fetal inflammatory response have been reported in the context of PPROM and intra-amniotic infection. Some of these markers have also been tested in amniotic fluid (AF) samples.

AIMS

This study compared markers of the inflammatory response in women with PPROM against the outcome standard of histological chorioamnionitis (HCA) or funisitis (FUS).

METHODS

Searches were conducted for studies reporting diagnostic test sensitivity and specificity for proven HCA or FUS in pregnant women with PPROM after 20 weeks' gestation. Weighted mean pooled sensitivity (Se), specificity (Sp), positive predictive value, negative predictive value, diagnostic odds ratio and 95% confidence intervals were calculated for each of the selected diagnostic tests.

RESULTS

Except ultrasonographic detection of fetal thymic involution, almost all index tests analysed showed relatively low sensitivity. Maternal white cell count, interleukin-6 (IL-6) and AF IL-6 had credible specificity. Testing of AF markers, while more consistent than serum markers, showed no clear diagnostic accuracy improvement.

CONCLUSIONS

There is a clear lack of evidence for the reliability of any individual diagnostic test to assist in the detection of HCA or FUS in women with PPROM. Combining several markers into a predictive model for improved diagnosis may be worth investigating.

Circulating Cell-Free Mitochondrial DNA as a Novel Biomarker for Intra-Amniotic Infection in Obstetrics: A Pilot Trial

Background/Objectives: Intra-amniotic infection (IAI) is a rare but serious condition with potential complications such as preterm labor and intrauterine fetal death. Diagnosing IAI is challenging due to varied clinical signs. Oxidative stress and mitochondrial dysfunction have been hypothesized to evolve around IAI. This study focused on measuring circulating mtDNA levels, a proposed biomarker for mitochondrial dysfunction, in maternal serum and placenta of women with confirmed IAI and healthy controls. Methods: 12 women with confirmed IAI (IAI group) were enrolled following premature preterm rupture of the membranes (PPROM) and compared to 21 healthy women (control group). Maternal blood was obtained two weeks pre-partum and peripartum; furthermore, postpartum placental blood was taken. In the IAI group, maternal blood was taken once weekly until delivery as well as peripartum, as was placental blood. Circulating cell-free mtDNA was quantified by real-time quantitative PCR. Results: Upon admission, in the IAI group, mean plasma mtDNA levels were 735.8 fg/μL compared to 134.0 fg/μL in the control group (p < 0.05). After delivery, in the IAI group, mean mtDNA levels in the placenta were 3010 fg/μL versus 652.4 fg/μL (p < 0.05). Conclusions: Circulating cell-free mtDNA could serve as a valuable biomarker for IAI prediction and diagnosis. Future research should establish reference values for sensitivity in predicting IAI.

Clinical utility of gastric fluid cytokine levels in preterm infants for predicting histological chorioamnionitis

BACKGROUND

The risk of various complications, such as neonatal death, early onset sepsis, and chronic lung disease, is increased in infants born to mothers with chorioamnionitis (CAM). However, predicting the diagnosis of histological CAM (hCAM) in the early postnatal period is challenging for clinicians due to pathological considerations. Therefore, an early diagnostic tool for hCAM is needed. Gastric fluid at birth is considered a suitable biomarker for predicting the intrauterine environment because most of its components are from amniotic fluid, and the sampling technique is less invasive. This study aimed to evaluate the clinical utility of cytokines in the gastric fluid of preterm infants at birth as predictors of hCAM.

METHODS

We retrieved gastric fluid and serum from 21 preterm infants with a gestational age of ≤ 32 weeks within 1 h after birth and used cytometric bead array to measure the concentrations of interleukin (IL)-2, IL-4, IL-6, IL-10, tumor necrosis factor-alpha, and interferon-gamma. We compared the cytokine concentrations in the gastric fluid and serum of the preterm infants born to mothers with or without hCAM.

RESULTS

The gastric fluid, serum IL-6, and serum IL-10 concentrations were significantly higher in the hCAM group than that in the non-hCAM group. The best cutoff values for predicting hCAM was > 2,855 pg/mL and > 315 pg/mL for IL-6 in the gastric fluid and serum, respectively. Receiver operating characteristic curves showed that gastric fluid IL-6 concentrations correlated more strongly with the presence of hCAM than serum IL-6 concentrations.

CONCLUSION

IL-6 in the gastric fluid at birth may be a more promising biomarker for predicting the presence of hCAM than that in serum. IL-6 concentration analysis in the gastric fluid at birth might help to diagnose hCAM immediately after birth and improve the prognosis of preterm infants.

Predictive Value of the sFlt-1/PlGF Ratio and Interleukin-6 for the Presence of Placental Lesions in Spontaneous Preterm Labor with Intact Membranes with Delivery within 7 Days

INTRODUCTION

The aim of the study was to identify predictive values of the soluble fms-like tyrosine kinase/placental growth factor (sFlt-1/PlGF) ratio and interleukin (IL)-6, assessed with a clinically available method in a large-volume biochemistry laboratory, in maternal blood, amniotic fluid, and umbilical cord blood for the presence of the placental lesions consistent with maternal vascular malperfusion (MVM) and acute histological chorioamnionitis (HCA), respectively.

METHODS

This retrospective study included 92 women with preterm labor with intact membranes (PTL) delivered within 7 days of admission with gestational ages between 22+0 and 34+6 weeks. The sFlt-1/PlGF ratio and IL-6 were assessed in stored samples of maternal serum, amniotic fluid, and umbilical cord serum using Elecsys® sFlt-1, PlGF, and IL-6 immunoassays.

RESULTS

Women with MVM had a higher sFlt-1/PlGF ratio in the maternal serum, compared to those without MVM (19.9 vs. 4.6; p < 0.0001), but not in the amniotic fluid or umbilical cord blood. A cut-off value of 8 for the sFlt-1/PlGF ratio in maternal serum was identified as optimal for predicting MVM in patients with PTL. Women with HCA had higher concentrations of IL-6 in maternal serum, compared to those without HCA (11.1 pg/mL vs. 8.4 pg/mL; p = 0.03), amniotic fluid (9,216 pg/mL vs. 1,423 pg/mL; p < 0.0001), and umbilical cord blood (20.7 pg/mL vs. 10.7 pg/mL, p = 0.002). Amniotic-fluid IL-6 showed the highest predictive value. A cut-off value of IL-6 concentration in the amniotic fluid of 5,000 pg/mL was found to be optimal for predicting HCA in PTL.

CONCLUSION

Maternal serum sFlt-1/PlGF and amniotic fluid IL-6 concentrations can be used for liquid biopsy to predict placental lesions in women with PTL who deliver within 7 days.

Anti-infectious and anti-inflammatory effect of amniopatch in the treatment of spontaneous previable rupture of membranes

Spontaneous previable rupture of membranes complicates approximately 0.4-0.7% of pregnancies and is associated with severe maternal and neonatal morbidity and mortality. Intra-amniotic inflammation is present in up to 94.4% of cases, most often caused by a bacterial infection. In comparison, the effectiveness of antibiotic therapy in its eradication reaches less than 17%. Inflammatory activity in the amniotic cavity disrupts the physiological development of the fetus with an increase in maternal, fetal, and neonatal inflammatory morbidity through the development of fetal inflammatory response syndrome, maternal chorioamnionitis, and neonatal sepsis. Amniopatch is an invasive therapeutic technique based on intra-amniotic administration of maternal hemoderivates in the form of thromboconcentrate and plasma cryoprecipitate to provide the temporary closure of the fetal membranes defect and secondary restitution of normohydramnios with correction of pressure-volume ratios. The supposed basis of this physical-mechanical action is the aggregation of coagulant components of amniopatch in the area of the defect with the formation of a valve cap. The background for the formulation of the hypothesis on the potential anti-infectious and anti-inflammatory action of non-coagulant components of amniopatch involved: i) clinical-academic and publishing outputs of the authors based on their many years' experience with amniopatch application in the treatment of spontaneous previable rupture of membranes (2008-2019), ii) the documented absence of clinically manifested chorioamnionitis in patients treated this way with a simultaneously reduced incidence of neonatal respiratory distress syndrome compared to expectant management (tocolysis, corticotherapy, antibiotic therapy). The non-coagulant components of plasma cryoprecipitate include mainly naturally occurring isohemagglutinins, albumin, and soluble plasma fibrinogen. Although these components of the amniopatch have not been attributed a significant therapeutic role, the authors assume that due to their opsonizing and aggregative properties, they can significantly participate in optimizing the intrauterine environment through the reduction in bacterial and cytokine charge in the amniotic fluid. The authors think these facts constitute a vital stimulus to future research-academic activity and, at the same time, an idea for reconsidering the therapeutic role of amniopatch as a tool for improving perinatal results of spontaneous previable ruptures of membranes.

Predictive potential of various plasma inflammation-, angiogenesis-, and extracellular matrix remodeling-associated mediators for intra-amniotic inflammation and/or microbial invasion of the amniotic cavity in preterm labor

PURPOSE

To determine whether various inflammatory-, angiogenic/anti-angiogenic-, and extracellular matrix remodeling-associated proteins in plasma, alone or in combination with conventional blood-based markers, can predict intra-amniotic inflammation and/or microbial invasion of the amniotic cavity (IAI/MIAC) in women with spontaneous preterm labor (PTL).

METHODS

A total of 193 singleton pregnant women with PTL (23-33 weeks) were included in this retrospective cohort study. Plasma samples were obtained at the time of amniocentesis. Amniotic fluid (AF) was cultured for microorganism detection and consequent MIAC diagnosis. IL-6 levels were determined in AF and used to identify IAI (AF IL-6 ≥ 2.6 ng/mL). Endostatin, haptoglobin, IGFBP-2/3, LBP, M-CSF, MMP-2/8, pentraxin 3, PlGF, S100A8/A9, and VEGFR-1 levels were assayed in plasma samples by ELISA. CRP levels and neutrophil-to-lymphocyte ratio (NLR) were measured.

RESULTS

Plasma LBP, MMP-8, and S100A8/A9 levels, CRP levels, and NLR were significantly higher, and plasma IGFBP-2 and MMP-2 levels were significantly lower in women with IAI/MIAC than in those without this condition, whereas no baseline variables differed significantly between the two groups. Using a stepwise regression analysis, a noninvasive prediction model for IAI/MIAC was developed, which included plasma LBP, MMP-2, and MMP-8 levels (area under the curve [AUC], 0.785). The AUC for this prediction model was significantly or borderline greater than that of any single factor included in the model.

CONCLUSIONS

IGFBP-2, LBP, MMP-2, MMP-8, and S100A8/A9 may represent valuable plasma biomarkers for predicting IAI/MIAC in women with PTL. Combination of LBP, MMP-2, and MMP-8 expression data can significantly improve the predictive potential for IAI/MIAC.

Identification and characterization of plasma proteins associated with intra-amniotic inflammation and/or infection in women with preterm labor

This study aimed to identify plasma proteins that could serve as potential biomarkers for microbial invasion of the amniotic cavity (MIAC) or intra-amniotic inflammation (IAI) in women with preterm labor (PTL). A retrospective cohort comprised singleton pregnant women with PTL (24-34 weeks) who underwent amniocentesis. Pooled plasma samples were analyzed by label-free liquid chromatography-tandem mass spectrometry for proteome profiling in a nested case-control study (concomitant MIAC/IAI cases vs. non-MIAC/IAI controls [n = 10 per group]). Eight target proteins associated with MIAC/IAI were further verified by immunoassays in a large cohort (n = 230). Shotgun proteomic analysis revealed 133 differentially expressed proteins (fold change > 1.5, P < 0.05) in the plasma of MIAC/IAI cases. Further quantification confirmed that the levels of AFP were higher and those of kallistatin and TGFBI were lower in the plasma of women with MIAC and that the levels of kallistatin and TGFBI were lower in the plasma of women with IAI than in those without these conditions. The area under the curves of plasma AFP, kallistatin, and TGFBI ranged within 0.67-0.81 with respect to each endpoint. In summary, plasma AFP, kallistatin, and TGFBI may represent valuable non-invasive biomarkers for predicting MIAC or IAI in women with PTL.

The vaginal immunoproteome for the prediction of spontaneous preterm birth: A retrospective longitudinal study

Background

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Most cases of preterm birth occur spontaneously and result from preterm labor with intact (spontaneous preterm labor [sPTL]) or ruptured (preterm prelabor rupture of membranes [PPROM]) membranes. The prediction of spontaneous preterm birth (sPTB) remains underpowered due to its syndromic nature and the dearth of independent analyses of the vaginal host immune response. Thus, we conducted the largest longitudinal investigation targeting vaginal immune mediators, referred to herein as the immunoproteome, in a population at high risk for sPTB.

Methods

Vaginal swabs were collected across gestation from pregnant women who ultimately underwent term birth, sPTL, or PPROM. Cytokines, chemokines, growth factors, and antimicrobial peptides in the samples were quantified via specific and sensitive immunoassays. Predictive models were constructed from immune mediator concentrations.

Results

Throughout uncomplicated gestation, the vaginal immunoproteome harbors a cytokine network with a homeostatic profile. Yet, the vaginal immunoproteome is skewed toward a pro-inflammatory state in pregnant women who ultimately experience sPTL and PPROM. Such an inflammatory profile includes increased monocyte chemoattractants, cytokines indicative of macrophage and T-cell activation, and reduced antimicrobial proteins/peptides. The vaginal immunoproteome has improved predictive value over maternal characteristics alone for identifying women at risk for early (<34 weeks) sPTB.

Conclusions

The vaginal immunoproteome undergoes homeostatic changes throughout gestation and deviations from this shift are associated with sPTB. Furthermore, the vaginal immunoproteome can be leveraged as a potential biomarker for early sPTB, a subset of sPTB associated with extremely adverse neonatal outcomes.

Funding

This research was conducted by the Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under contract HHSN275201300006C. ALT, KRT, and NGL were supported by the Wayne State University Perinatal Initiative in Maternal, Perinatal and Child Health.

Semi-quantitative metalloproteinase-8 rapid test for the prediction of adverse pregnancy outcomes in patients with preterm premature rupture of membranes

OBJECTIVE

We aimed to determine whether the semi-quantitative metalloproteinase-8 (MMP-8) bedside test is a worthwhile indicator in reflecting the severity of of intra-amniotic inflammation (IAI) and in predicting adverse pregnancy outcomes.

STUDY DESIGN

This retrospective cohort study comprised 76 singleton-pregnant women admitted to the Seoul National University Bundang Hospital with a diagnosis of preterm premature rupture of membranes (preterm PROM) between 20 weeks 0 days and 33 weeks 6 days of gestation who underwent trans-abdominal amniocentesis to confirm intra-amniotic infection by positive results for aerobic/anaerobic bacteria, fungi, and genital mycoplasma and evaluate lung maturity. The semi-quantitative MMP-8 rapid test kit employs a colourimetric assay to quantify MMP-8 levels in amniotic fluid (AF), expressing results from 0 to 100 percent. Participants were divided into three groups: group 1, including negative MMP-8 test with colour scale of 0 % (negative, n = 17); group 2, including positive MMP-8 test with colour scale < 51 % (weak positive, n = 21); and group 3, including positive MMP-8 test with colour scale of 51 %-100 % (strong positive, n = 38).

RESULTS

Approximately 78 % (59/76) of the participants showed a positive MMP-8 test result; all culture-proven AF samples (33.3 % [25/75]) yielded positive MMP-8 test, categorizing these patients into either group 2 or group 3. A significant trend was observed where the rate of positive culture-proven samples increased with the progression from group 1 (negative) to group 3 (strong positive). Both white blood cell counts in AF and maternal serum C-reactive protein levels were found to escalate with the progression of test results from negative to strong positive. This progression was associated with an increased risk of spontaneous preterm birth within 48 h, 7 days, and 14 days from amniocentesis and within 34 weeks of gestation.

CONCLUSION

The more the test results progress from negative to strong positive, the shorter the interval from amniocentesis to delivery becomes, and the higher the risk of intra-amniotic infection, spontaneous preterm delivery, and other perinatal complications. This relationship highlights the critical value of the semi-quantitative MMP-8 rapid test in predicting adverse pregnancy outcomes in patients with preterm PROM.

The role of neutrophils and neutrophil extracellular traps (NETs) in stages, outcomes and pregnancy complications

Neutrophils are the main components of innate immunity to eliminate infectious pathogens. Neutrophils play a role in several stages of the reproductive cycle, and their presence in the female reproductive system is highly regulated, so their function may change during pregnancy. Emerging evidence suggests that neutrophils are important at all stages of pregnancy, from implantation, placentation, and connective tissue regeneration to birth, as well as birth itself. Neutrophil extracellular traps (NETs) are defined as extracellular strands of unfolded DNA together with histone complexes and neutrophil granule proteins. NET formation is a new mechanism of these cells for their defense function. These strands containing DNA and antimicrobial peptides were initially recognized as one of the defense mechanisms of neutrophils, but later it was explained that they are involved in a variety of non-infectious diseases. Since the source of inflammation and tissue damage is the irregular activity of neutrophils, it is not surprising that NETosis are associated with a number of inflammatory conditions and diseases. The overexpression of NET components or non-principled NET clearance is associated with the risk of production and activation of autoantibodies, which results in participation in autoinflammatory and autoimmune disorders (SLE, RA), fibrosis, sepsis and other disorders such as vascular diseases, for example, thrombosis and atherosclerosis. Recent published articles have shown the role of neutrophils and extracellular traps (NETs) in pregnancy, childbirth and pregnancy-related diseases. The aim of this study was to identify and investigate the role of neutrophils and neutrophil extracellular traps (NETs) in the stages of pregnancy, as well as the complications caused by these cells.

Measurements of Interleukin-8 and Matrix Metalloproteinases-9 in Cervicovaginal Fluid in Women with Preterm Labor: A Direct Comparison with Amniotic Fluid

OBJECTIVE

We aimed to evaluate the correlation and agreement of interleukin (IL)-8 and matrix metalloproteinases (MMP-9) levels between cervicovaginal (CVF) and amniotic fluids (AF) in women with preterm labor (PTL) and to determine the clinical values of these proteins in CVF compared with those in AF.

STUDY DESIGN

We designed a retrospective cohort study of 85 singleton pregnant women with PTL at 23 to 34 weeks, who underwent amniocentesis. The AF was cultured, and CVF samples were collected at the time of amniocentesis. Paired AF and CVF samples were assayed for IL-8 and MMP-9 by enzyme-linked immunoassay (ELISA) in duplicate on a single plate, using similar dilution ratios.

RESULTS

A significant but weak correlation was found for IL-8 levels between AF and CVF (r = 0.333), while no correlation was found for MMP-9 levels between AF and CVF (r = -0.039). Intra-class correlation coefficient for the agreement of IL-8 levels between CVF and AF was 0.4335 and -0.279 for MMP-9, indicating a poor-to-fair level of agreement between the two measured values, respectively. IL-8 and MMP-9 levels in CVF were not associated with the risk of either microbial invasion of the amniotic cavity (MIAC) or spontaneous preterm delivery (SPTD) within 7 days, whereas those in AF provided good-to-excellent predictive values for these two outcomes (area under the curve [AUCs]: 0.82-0.95). AUCs for IL-8 and MMP-9 were significantly larger using AF rather than using CVF for the prediction of MIAC and SPTD.

CONCLUSION

In women with PTL, IL-8 and MMP-9 levels in CVF do not precisely reflect the levels of the corresponding proteins in AF. IL-8 and MMP-9 levels in CVF had poor predictive values for the risk of MIAC and SPTD and were significantly inferior to those in AF.

KEY POINTS

· IL-8 and MMP-9 levels in CVF do not precisely reflect levels of the corresponding proteins in AF.. · Diagnostic accuracy of IL-8 and MMP-9 in CVF alone is not sufficient to predict MIAC and SPTD.. · IL-8 and MMP-9 levels in AF provide good-to-excellent predictive values for these two outcomes..

Characterizing Histopathologic Features in Pregnancies With Chronic Histiocytic Intervillositis Using Computerized Image Analysis

CONTEXT.—

Chronic histiocytic intervillositis (CHI) is a rare condition characterized by maternal immune cell infiltration into the human placenta. CHI is strongly associated with fetal growth restriction, miscarriage, and stillbirth, and knowledge of its etiology, and consequently effective treatment, is limited. Currently, diagnosis is largely subjective and varies between centers, making comparison between studies challenging.

OBJECTIVE.—

To objectively quantify and interrelate inflammatory cells and fibrin in placentas with CHI compared with controls and determine how pathology may be altered in subsequent pregnancies following diagnosis. Macrophage phenotype was also investigated in untreated cases of CHI.

DESIGN.—

Computerized analysis was applied to immunohistochemically stained untreated (index) cases of CHI, subsequent pregnancies, and controls. Index placentas were additionally stained by immunofluorescence for M1 (CD80 and CD86) and M2 macrophage markers (CD163 and CD206).

RESULTS.—

Quantification revealed a median 32-fold increase in macrophage infiltration in index cases versus controls, with CHI recurring in 2 of 11 (18.2%) subsequent pregnancies. A total of 4 of 14 placentas (28.6%) with a diagnosis of CHI did not exhibit infiltration above controls. Macrophages in index pregnancies strongly expressed CD163. There was no significant difference in fibrin deposition between index cases and controls, although subsequent pregnancies displayed a 2-fold decrease compared with index pregnancies. CD3+ T cells were significantly elevated in index pregnancies; however, they returned to normal levels in subsequent pregnancies.

CONCLUSIONS.—

In CHI, intervillous macrophages expressed CD163, possibly representing an attempt to resolve inflammation. Computerized analysis of inflammation in CHI may be useful in determining how treatment affects recurrence, and alongside pathologist expertise in grading lesion severity.

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

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

Deciphering maternal-fetal cross-talk in the human placenta during parturition using single-cell RNA sequencing

Labor is a complex physiological process requiring a well-orchestrated dialogue between the mother and fetus. However, the cellular contributions and communications that facilitate maternal-fetal cross-talk in labor have not been fully elucidated. Here, single-cell RNA sequencing (scRNA-seq) was applied to decipher maternal-fetal signaling in the human placenta during term labor. First, a single-cell atlas of the human placenta was established, demonstrating that maternal and fetal cell types underwent changes in transcriptomic activity during labor. Cell types most affected by labor were fetal stromal and maternal decidual cells in the chorioamniotic membranes (CAMs) and maternal and fetal myeloid cells in the placenta. Cell-cell interaction analyses showed that CAM and placental cell types participated in labor-driven maternal and fetal signaling, including the collagen, C-X-C motif ligand (CXCL), tumor necrosis factor (TNF), galectin, and interleukin-6 (IL-6) pathways. Integration of scRNA-seq data with publicly available bulk transcriptomic data showed that placenta-derived scRNA-seq signatures could be monitored in the maternal circulation throughout gestation and in labor. Moreover, comparative analysis revealed that placenta-derived signatures in term labor were mirrored by those in spontaneous preterm labor and birth. Furthermore, we demonstrated that early in gestation, labor-specific, placenta-derived signatures could be detected in the circulation of women destined to undergo spontaneous preterm birth, with either intact or prelabor ruptured membranes. Collectively, our findings provide insight into the maternal-fetal cross-talk of human parturition and suggest that placenta-derived single-cell signatures can aid in the development of noninvasive biomarkers for the prediction of preterm birth.

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

BACKGROUND

Preterm birth preceded by spontaneous preterm labour often occurs in the clinical setting of sterile intra-amniotic inflammation (SIAI), a condition that currently lacks treatment.

METHODS

Proteomic and scRNA-seq human data were analysed to evaluate the role of IL-6 and IL-1α in SIAI. A C57BL/6 murine model of SIAI-induced preterm birth was developed by the ultrasound-guided intra-amniotic injection of IL-1α. The blockade of IL-6R by using an aIL-6R was tested as prenatal treatment for preterm birth and adverse neonatal outcomes. QUEST-MRI evaluated brain oxidative stress in utero. Targeted transcriptomic profiling assessed maternal, foetal, and neonatal inflammation. Neonatal biometrics and neurodevelopment were tested. The neonatal gut immune-microbiome was evaluated using metagenomic sequencing and immunophenotyping.

FINDINGS

IL-6 plays a critical role in the human intra-amniotic inflammatory response, which is associated with elevated concentrations of the alarmin IL-1α. Intra-amniotic injection of IL-1α resembles SIAI, inducing preterm birth (7% vs. 50%, p = 0.03, Fisher's exact test) and neonatal mortality (18% vs. 56%, p = 0.02, Mann-Whitney U-test). QUEST-MRI revealed no foetal brain oxidative stress upon in utero IL-1α exposure (p > 0.05, mixed linear model). Prenatal treatment with aIL-6R abrogated IL-1α-induced preterm birth (50% vs. 7%, p = 0.03, Fisher's exact test) by dampening inflammatory processes associated with the common pathway of labour. Importantly, aIL-6R reduces neonatal mortality (56% vs. 22%, p = 0.03, Mann-Whitney U-test) by crossing from the mother to the amniotic cavity, dampening foetal organ inflammation and improving growth. Beneficial effects of prenatal IL-6R blockade carried over to neonatal life, improving survival, growth, neurodevelopment, and gut immune homeostasis.

INTERPRETATION

IL-6R blockade can serve as a strategy to treat SIAI, preventing preterm birth and adverse neonatal outcomes.

FUNDING

NICHD/NIH/DHHS, Contract HHSN275201300006C. WSU Perinatal Initiative in Maternal, Perinatal and Child Health.

Clinical chorioamnionitis at term is characterized by changes in the plasma concentration of CHCHD2/MNRR1, a mitochondrial protein

OBJECTIVE

Mitochondrial dysfunction was observed in acute systemic inflammatory conditions such as sepsis and might be involved in sepsis-induced multi-organ failure. Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 2 (CHCHD2), also known as Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1), a bi-organellar protein located in the mitochondria and the nucleus, is implicated in cell respiration, survival, and response to tissue hypoxia. Recently, the reduction of the cellular CHCHD2/MNRR1 protein, as part of mitochondrial dysfunction, has been shown to play a role in the amplification of inflammatory cytokines in a murine model of lipopolysaccharide-induced systemic inflammation. The aim of this study was to determine whether the plasma concentration of CHCHD2/MNRR1 changed during human normal pregnancy, spontaneous labor at term, and clinical chorioamnionitis at term.

METHODS

We conducted a cross-sectional study that included the following groups: 1) non-pregnant women (n = 17); 2) normal pregnant women at various gestational ages from the first trimester until term (n = 110); 3) women at term with spontaneous labor (n = 50); and 4) women with clinical chorioamnionitis at term in labor (n = 25). Plasma concentrations of CHCHD2/MNRR1 were assessed by an enzyme-linked immunosorbent assay.

RESULTS

1) Pregnant women at term in labor with clinical chorioamnionitis had a significantly higher plasma CHCHD2/MNRR1 concentration than those in labor without chorioamnionitis (p = .003); 2) CHCHD2/MNRR1 is present in the plasma of healthy non-pregnant and normal pregnant women without significant differences in its plasma concentrations between the two groups; 3) there was no correlation between maternal plasma CHCHD2/MNRR1 concentration and gestational age at venipuncture; and 4) plasma CHCHD2/MNRR1 concentration was not significantly different in women at term in spontaneous labor compared to those not in labor.

CONCLUSIONS

CHCHD2/MNRR1 is physiologically present in the plasma of healthy non-pregnant and normal pregnant women, and its concentration does not change with gestational age and parturition at term. However, plasma CHCHD2/MNRR1 is elevated in women at term with clinical chorioamnionitis. CHCHD2/MNRR1, a novel bi-organellar protein located in the mitochondria and the nucleus, is released into maternal plasma during systemic inflammation.

Evidence for the participation of CHCHD2/MNRR1, a mitochondrial protein, in spontaneous labor at term and in preterm labor with intra-amniotic infection

OBJECTIVE

Intra-amniotic inflammation (IAI), associated with either microbe (infection) or danger signals (sterile), plays a major role in the pathophysiology of preterm labor and delivery. Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 2 (CHCHD2) [also known as Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1)], a mitochondrial protein involved in oxidative phosphorylation and cell survival, is capable of sensing tissue hypoxia and inflammatory signaling. The ability to maintain an appropriate energy balance at the cellular level while adapting to environmental stress is essential for the survival of an organism. Mitochondrial dysfunction has been observed in acute systemic inflammatory conditions, such as sepsis, and is proposed to be involved in sepsis-induced multi-organ failure. The purpose of this study was to determine the amniotic fluid concentrations of CHCHD2/MNRR1 in pregnant women, women at term in labor, and those in preterm labor (PTL) with and without IAI.

METHODS

This cross-sectional study comprised patients allocated to the following groups: (1) mid-trimester (n = 16); (2) term in labor (n = 37); (3) term not in labor (n = 22); (4) PTL without IAI who delivered at term (n = 25); (5) PTL without IAI who delivered preterm (n = 47); and (6) PTL with IAI who delivered preterm (n = 53). Diagnosis of IAI (amniotic fluid interleukin-6 concentration ≥2.6 ng/mL) included cases associated with microbial invasion of the amniotic cavity and those of sterile nature (absence of detectable bacteria, using culture and molecular microbiology techniques). Amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations were determined with a validated and sensitive immunoassay.

RESULTS

(1) CHCHD2/MNRR1 was detectable in all amniotic fluid samples and women at term without labor had a higher amniotic fluid CHCHD2/MNRR1 concentration than those in the mid-trimester (p = 0.003); (2) the amniotic fluid concentration of CHCHD2/MNRR1 in women at term in labor was higher than that in women at term without labor (p = 0.01); (3) women with PTL and IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those without IAI, either with preterm (p < 0.001) or term delivery (p = 0.01); (4) women with microbial-associated IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those with sterile IAI (p < 0.001); (5) among women with PTL and IAI, the amniotic fluid concentration of CHCHD2/MNRR1 correlated with that of interleukin-6 (Spearman's Rho = 0.7; p < 0.001); and (6) no correlation was observed between amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations among women with PTL.

CONCLUSION

CHCHD2/MNRR1 is a physiological constituent of human amniotic fluid in normal pregnancy, and the amniotic concentration of this mitochondrial protein increases during pregnancy, labor at term, and preterm labor with intra-amniotic infection. Hence, CHCHD2/MNRR1 may be released into the amniotic cavity by dysfunctional mitochondria during microbial-associated IAI.

Physical examination-indicated cerclage in twin pregnancies compared with singleton pregnancies

OBJECTIVE

The aim of this study was to compare pregnancy outcomes of physical examination-indicated cerclage in twin and singleton pregnancies with bulging membranes.

METHODS

All women with bulging membranes in the second trimester of pregnancy who were admitted to La Fe University and Polytechnic Hospital from January 2009 to January 2022 were included. A total of 128 participants were enrolled, 102 singleton pregnancies and 26 twin pregnancies. All patients underwent an amniocentesis to rule out intra-amniotic inflammation (IL-6 < 2.6 ng/mL). Cerclage was placed in the absence of intra-amniotic inflammation.

RESULTS

Compared with singleton gestations, twin pregnancies displayed a significantly higher prevalence of nulliparity and assisted reproductive techniques. The incidence of intra-amniotic inflammation/infection was similar in both groups (68.62% in singleton vs. 65.38% in twin pregnancies). The average gestational age of delivery without cerclage in singleton gestations was 23.83 weeks (95% CI 22.82-24.84) and in twin pregnancies, it was 23.69 weeks (95% CI 21.8-25.57). The average gestational age at delivery among patients with cerclage was 37.27 weeks (95% CI 35.35-39.19) in singleton gestations and 36 weeks (95% CI 33.51-38.63) in twin pregnancies, with no significant differences. Time from diagnosis to delivery in patients with IL-6 < 2.6 ng/mL was 79.88 days, and in those with IL > 2.6 ng/mL was 10.87 days. Gestational age at delivery was significantly higher in both singleton and twin pregnancies with cerclage, compared with those without cerclage (log-rank p < .001).

CONCLUSIONS

Singleton and twin pregnancies with bulging membranes behave similarly when cerclage is placed in the absence of intraamniotic inflammation/infection.

Maternal and infant microbiome: next-generation indicators and targets for intergenerational health and nutrition care

Microbes are commonly sensitive to shifts in the physiological and pathological state of their hosts, including mothers and babies. From this perspective, the microbiome may be a good indicator for diseases during pregnancy and has the potential to be used for perinatal health monitoring. This is embodied in the application of microbiome from multi body sites for auxiliary diagnosis, early prediction, prolonged monitoring, and retrospective diagnosis of pregnancy and infant complications, as well as nutrition management and health products developments of mothers and babies. Here we summarized the progress in these areas and explained that the microbiome of different body sites is sensitive to different diseases and their microbial biomarkers may overlap between each other, thus we need to make a diagnosis prudently for those diseases. Based on the microbiome variances and additional anthropometric and physical data, individualized responses of mothers and neonates to meals and probiotics/prebiotics were predictable, which is of importance for precise nutrition and probiotics/prebiotics managements and developments. Although a great deal of encouraging performance was manifested in previous studies, the efficacy could be further improved by combining multi-aspect data such as multi-omics and time series analysis in the future. This review reconceptualizes maternal and infant health from a microbiome perspective, and the knowledge in it may inspire the development of new options for the prevention and treatment of adverse pregnancy outcomes and bring a leap forward in perinatal health care.

Chorioamnionitis: An Update on Diagnostic Evaluation

Chorioamnionitis remains a major cause of preterm birth and maternal and neonatal morbidity. We reviewed the current evidence for the diagnostic tests of chorioamnionitis and how this relates to clinical practice today. A comprehensive literature search and review was conducted on chorioamnionitis and intra-uterine inflammation. Data from randomized control trials and systematic reviews were prioritized. This review highlights that sterile inflammation plays an important role in chorioamnionitis and that the current tests for chorioamnionitis including clinical criteria, maternal plasma and vaginal biomarkers lack diagnostic accuracy. Concerningly, these tests often rely on detecting an inflammatory response after damage has occurred to the fetus. Care should be taken when interpreting current investigations for the diagnosis of chorioamnionitis and how they guide obstetric/neonatal management. There is an urgent need for further validation of current diagnostic tests and the development of novel, accurate, minimally invasive tests that detect subclinical intra-uterine inflammation.

Abnormal Vaginal Flora in Cervical Incompetence Patients - the Impact of Escherichia coli

The purpose of this study was to investigate the prevalence of abnormal vaginal colonization in women with cervical incompetence and to analyze its impact on obstetric and neonatal outcomes and placental inflammation. We included 138 pregnant women diagnosed with cervical incompetence and delivered in our hospital. Patients with major fetal anomaly or multifetal pregnancy were excluded. Upper vaginal culture was performed on the day of admission. A total of 60.9% (84/138) of cervical incompetence patients had abnormal bacterial colonization, and Escherichia coli (E. coli) was the most common colonized pathogen (33.3%, 46/138). The positive vaginal E. coli group had a higher rate of prior preterm birth (p = 0.021) and an earlier gestational age at which cervical incompetence was diagnosed (p < 0.01) than the negative group. The positive vaginal E. coli group had higher rates of clinical chorioamnionitis (p = 0.008) and subchorionic microabscess of the placenta (p = 0.012). Importantly, the positive vaginal E. coli group had significantly higher rates of proven early-onset neonatal sepsis (EONS) (p = 0.046), necrotizing enterocolitis (NEC) (p = 0.001), and neonatal mortality (p = 0.023). After adjusting for confounding variables, the positive vaginal E. coli group had significantly higher risk for proven EONS (OR: 3.853, 95% CI: 1.056-14.055) and NEC (OR: 12.410, 95% CI: 1.290-119.351). In conclusion, E. coli was the most common vaginal microorganism isolated from patients with cervical incompetence. Maternal vaginal E. coli colonization was associated with adverse neonatal outcomes including proven EONS and NEC and was characterized by a higher rate of placental subchorionic microabscess.

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

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

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

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

Extracellular matrix-related and serine protease proteins in the amniotic fluid of women with early preterm labor: Association with spontaneous preterm birth, intra-amniotic inflammation, and microbial invasion of the amniotic cavity

PROBLEM

We aimed to determine whether altered levels of various extracellular matrix (ECM)-related and serine protease proteins in the amniotic fluid (AF) are associated with imminent spontaneous preterm birth (SPTB; ≤7 days) and intra-amniotic inflammation and/or microbial invasion of the amniotic cavity (IAI/MIAC) in women with early preterm labor (PTL).

METHOD OF STUDY

This retrospective cohort study included 252 women with singleton pregnancies undergoing transabdominal amniocentesis who demonstrated PTL (24-31 weeks). The AF was cultured for microorganism detection to characterize MIAC. IL-6 concentrations were determined in the AF samples to identify IAI (≥2.6 ng/mL). The following mediators were measured in the AF samples using ELISA: kallistatin, lumican, MMP-2, SPARC, TGFBI, and uPA.

RESULTS

Kallistatin, MMP-2, TGFBI, and uPA levels were significantly higher and SPARC and lumican levels were significantly lower in the AF of women who spontaneously delivered within 7 days than in the AF of those who delivered after 7 days; the levels of the first five mediators were independent of baseline clinical variables. In the multivariate analysis, elevated levels of kallistatin, MMP-2, TGFBI, and uPA and low levels of lumican and SPARC in the AF were significantly associated with IAI/MIAC and MIAC, even after adjusting for the gestational age at sampling. The areas under the curves of the aforementioned biomarkers ranged from 0.58 to 0.87 for the diagnoses of each of the corresponding endpoints.

CONCLUSION

ECM-related (SPARC, TGFBI, lumican, and MMP-2) and serine protease (kallistatin and uPA) proteins in the AF are involved in preterm parturition and regulation of intra-amniotic inflammatory/infectious responses in PTL.

The fetal response to maternal inflammation is dependent upon maternal IL-6 in a murine model

BACKGROUND

The induction of maternal inflammation in mice leads to fetal injury that is believed to be IL-6 dependent. The fetal inflammatory response, defined by elevated fetal or amniotic fluid IL-6, has been described as a potential mechanism for subsequent fetal injury. The role of maternal IL-6 production and signaling in the fetal IL-6 response is currently unclear.

METHODS

Genetic and anti-IL-6 antibody strategies were used to systematically block the maternal IL-6 response during inflammation. Chorioamnionitis was induced using intraperitoneal injection of lipopolysaccharide (LPS) at mid gestation (E14.5) and late gestation (E18.5). This model was used in pregnant C57Bl/6 dams, IL6-/- dams, C57Bl/6 dams treated with anti-IL-6 (blocks both classical and trans-signaling) or anti-gp130 antibodies (blocks trans-signaling only) and IL6+/- dams. Six hours following LPS injection, maternal serum, placental tissue, amniotic fluid and fetal tissue or serum were collected. A bead-based multiplex assay was used to evaluate levels of IL-6, KC, IL-1β, TNF, IL-10, IL-22, IFN-γ, IL-13 and IL-17A.

RESULTS

Chorioamnionitis in C57Bl/6 dams was characterized by elevated maternal serum levels of IL-6, KC and IL-22 with litter loss during mid gestation. The fetal response to maternal inflammation in C57Bl/6 mice was primarily characterized by elevated levels of IL-6, KC and IL-22 in the placenta, amniotic fluid and fetus during both mid and late gestation. A global IL-6 knockout (IL6-/-) eradicated the maternal, placental, amniotic fluid and fetal IL-6 response to LPS during mid and late gestation and improved litter survival, while minimally influencing the KC or IL-22 responses. Blocking maternal classical IL-6 signaling in C57Bl/6 dams at the time of LPS exposure diminished the maternal, placental, amniotic fluid and fetal IL-6 response during mid and late gestation, while blocking maternal IL-6 trans-signaling only affected fetal IL-6 expression. To evaluate whether maternal IL-6 was crossing the placenta and reaching the fetus, IL-6+/- dams were utilized in the chorioamnionitis model. IL-6+/- dams mounted a systemic inflammatory response following injection with LPS, characterized by elevated IL-6, KC and IL-22. IL-6-/- pups born to IL6+/- dams had decreased amniotic fluid levels of IL-6 and undetectable levels of fetal IL-6 compared to IL-6+/+ littermate controls.

CONCLUSION

The fetal response to systemic maternal inflammation is dependent upon maternal IL-6 signaling, but maternal IL-6 is not crossing the placenta and reaching the fetus at detectable levels.

Amniotic fluid interleukin-6 and neutrophil gelatinase-associated lipocalin for predicting fetal inflammatory response syndrome based on histological chorioamnionitis and funisitis

OBJECTIVE

We aimed to analyze the predictive efficacy of amniotic fluid interleukin-6 (IL-6) and neutrophil gelatinase-associated lipocalin (NGAL) for fetal inflammatory response syndrome (FIRS)-related infection.

MATERIALS AND METHODS

We included singleton pregnancies classified into FIRS and non-FIRS groups. FIRS was defined as histologic chorioamnionitis and funisitis. Amniotic fluid samples were collected during vaginal delivery (VD) or cesarean section (CS). We compared amniotic fluid IL-6 and NGAL levels between the groups.

RESULTS

Forty-six pregnancies were analyzed and classified into 20 (43.5%) FIRS and 26 (56.5%) non-FIRS pregnancies. We observed significant differences in amniotic fluid IL-6 and NGAL. Amniotic fluid collection significantly influenced NGAL levels (p < 0.001). The area under the concentration-time curve (AUC), with optimal cutoff values, for amniotic fluid IL-6 and NGAL (VD and CS) levels was 0.948 (11,344 pg/mL), 0.800 (1180 ng/mL), and 0.946 (708 ng/mL), respectively.

CONCLUSION

Amniotic fluid IL-6 and NGAL levels showed equivalent predictive ability for FIRS-related infection.

Maternal plasma and salivary anelloviruses in pregnancy and preterm birth

Introduction

Human anelloviruses, including torque teno virus (TTV) and torque teno mini virus (TTMV), are ubiquitous in the general population and have no known pathogenicity. We investigated the prevalence and viral load of TTV and TTMV in plasma and saliva over pregnancy, and assessed their association with spontaneous or medically indicated preterm birth.

Methods

This is a secondary analysis of the Measurement of Maternal Stress (MOMS) study, which recruited 744 individuals with singleton pregnancies from 4 US sites (Chicago, Pittsburgh, San Antonio, and rural Pennsylvania). Baseline outpatient visits took place in the second trimester (between 12'0 and 20'6/7  weeks' gestation), and follow-up visits in the third trimester (between 32'0 and 35'6/7  weeks' gestation). In a case-control study design, participants who delivered preterm (<37 weeks) resulting from spontaneous labor and/or preterm premature rupture of membranes ("sPTB") were compared with participants experiencing medically indicated preterm birth ("iPTB"), or delivery at term ("controls"). Plasma and saliva samples obtained during the second and third trimesters were tested for the presence and quantity of TTV and TTMV using real-time PCR. Demographic data were obtained via self-report, and clinical data via medical record review by trained research personnel.

Results

TTV was detected in plasma from 81% (second trimester) and 77% (third trimester) of participants, and in saliva from 64 and 60%. Corresponding detection rates for TTMV were 59 and 41% in plasma, and 35 and 24% in saliva. TTV and TTMV concentrations were similar between matched plasma and saliva samples. TTV prevalence and concentrations were not significantly different between groups (sPTB, iPTB, and controls). However, plasma TTMV in the third trimester was associated with sPTB and earlier gestational age at delivery. The iPTB group was not different from either the sPTB or the control group. In saliva, concentrations of TTV and TTMV were similar among the three groups. Both TTV and TTMV were more prevalent with increasing parity and were more common in Black and Hispanic participants compared to non-Hispanic White participants.

Conclusion

Anellovirus presence (specifically, TTMV) in the third trimester may be associated with preterm birth. Whether this association is causative remains to be determined.

Clinical chorioamnionitis: where do we stand now?

Intraamniotic infection is an infection resulting in the inflammation of any combination of the amniotic fluid, the placenta, the fetus itself, the fetal membranes, umbilical cord, or the decidua. In the past, an infection of the amnion and chorion or both was dubbed chorioamnionitis. In 2015, a proposal was made by an expert panel that, instead of clinical chorioamnionitis, the name intrauterine inflammation or infection or both be used, abbreviated as Triple I or simply IAI. However, the abbreviation IAI did not gain popularity, and this article uses the term chorioamnionitis. Chorioamnionitis may arise prior to, during, or following labor. It can present as a chronic, subacute, or acute infection. Its clinical presentation is generally referred to as acute chorioamnionitis. The treatment of chorioamnionitis varies widely across the world due to different bacterial causes and the absence of sufficient evidence to support a specific treatment regimen. There are limited randomized controlled trials that have evaluated the superiority of antibiotic regimens for treating amniotic infections during labor. This lack of evidence-based treatment suggests that the current choice of antibiotics is based on limitations in existing research, rather than absolute science. Chorioamnionitis cannot be cured by antibiotic therapy alone without delivery, and therefore it is necessary to make a decision according to the guidelines for induction of labor or acceleration of delivery. When a diagnosis is suspected or established, it is therefore necessary to apply broad-spectrum antibiotics according to the protocol used by each country, and to continue with them until delivery. A commonly recommended first-line treatment for chorioamnionitis is a simple regimen consisting of amoxicillin or ampicillin and once-daily gentamicin. Available information is not sufficient to indicate the best antimicrobial regimen to treat this obstetric condition. However, the evidence that is currently available suggests that patients with clinical chorioamnionitis, primarily women with a gestational age of 34 weeks or more and those in labor, should receive treatment with this regime. However, antibiotic preferences may vary based on local policy, clinician experience and knowledge, bacterial reasons for the infection, antimicrobial resistance patterns, maternal allergies, and drug availability.

Tdap vaccination during pregnancy and risk of chorioamnionitis and related infant outcomes

INTRODUCTION

An increased risk of chorioamnionitis in people receiving tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during pregnancy has been reported. The importance of this association is unclear as additional study has not demonstrated increased adverse infant outcomes associated with Tdap vaccination in pregnancy.

METHODS

We conducted a retrospective observational cohort study of pregnant people ages 15-49 years with singleton pregnancies ending in live birth who were members of 8 Vaccine Safety Datalink (VSD) sites during October 2016-September 2018. We used a time-dependent covariate Cox model with stabilized inverse probability weights applied to evaluate associations between Tdap vaccination during pregnancy and chorioamnionitis and preterm birth outcomes. We used Poisson regression with robust variance with stabilized inverse probability weights applied to evaluate the association of Tdap vaccination with adverse infant outcomes. We performed medical record reviews on a random sample of patients with ICD-10-CM-diagnosed chorioamnionitis to determine positive predictive values (PPV) of coded chorioamnionitisfor "probable clinical chorioamnionitis," "possible clinical chorioamnionitis," or "histologic chorioamnionitis."

RESULTS

We included 118,211 pregnant people; 103,258 (87%) received Tdap vaccine during pregnancy; 8098 (7%) were diagnosed with chorioamnionitis. The adjusted hazard ratio for chorioamnionitis in the Tdap vaccine-exposed group compared to unexposed was 0.96 (95% CI 0.90-1.03). There was no association between Tdap vaccine and preterm birth or adverse infant outcomes associated with chorioamnionitis. Chart reviews were performed for 528 pregnant people with chorioamnionitis. The PPV for clinical (probable or possible clinical chorioamnionitis) was 48% and 59% for histologic chorioamnionitis. The PPV for the combined outcome of clinical or histologic chorioamnionitis was 81%.

CONCLUSIONS AND RELEVANCE

Tdap vaccine exposure during pregnancy was not associated with chorioamnionitis, preterm birth, or adverse infant outcomes. ICD-10 codes for chorioamnionitis lack specificity for clinical chorioamnionitis and should be a recognized limitation when interpreting results.

Relationship of maternal inflammatory response and fetal inflammatory response to duration and intensity of intra-amniotic infection and inflammation

INTRODUCTION

We aimed to use two indices, amniotic fluid interleukin-6 (IL-6) concentration at diagnosis and diagnosis-to-delivery interval, to clarify the frequencies of maternal inflammatory response (MIR) and fetal inflammatory response (FIR) in the placenta of patients with intra-amniotic infection and intra-amniotic inflammation (IAI).

METHODS

This is a single-center retrospective cohort study. From August 2014 to April 2020, participants were diagnosed with IAI with or without microbial invasion of the amniotic cavity (MIAC) using amniocentesis. IAI was defined as concentrations of amniotic IL-6 ≥ 2.6 ng/mL. MIAC was defined as a positive amniotic fluid culture. IAI with MIAC was defined as an intra-amniotic infection. We calculated the cut-off values for IL-6 concentration in the amniotic fluid at diagnosis and the diagnosis-to-delivery interval for MIR-positive cases among those with intra-amniotic infection.

RESULTS

The amniotic fluid IL-6 concentration at diagnosis and diagnosis-to-delivery interval were 15.8 ng/mL and 12 h, respectively. Among cases with intra-amniotic infection, MIR was 98% (52/53) positive, i.e., when either of the two cut-off values was exceeded. There were no significant differences between the frequencies of MIR and FIR. In cases with IAI but no MIAC, the frequencies of MIR and FIR were significantly lower than those with intra-amniotic infection, except when neither of the two cut-off values was exceeded.

DISCUSSION

We clarified the MIR- and FIR-positive cases in intra-amniotic infection and cases with IAI but no MIAC according to condition, including the diagnosis-to-delivery interval.

Intra-amniotic inflammation in the mid-trimester of pregnancy is a risk factor for neuropsychological disorders in childhood

OBJECTIVES

Intra-amniotic inflammation is a subclinical condition frequently caused by either microbial invasion of the amniotic cavity or sterile inflammatory stimuli, e.g., alarmins. An accumulating body of evidence supports a role for maternal immune activation in the genesis of fetal neuroinflammation and the occurrence of neurodevelopmental disorders such as cerebral palsy, schizophrenia, and autism. The objective of this study was to determine whether fetal exposure to mid-trimester intra-amniotic inflammation is associated with neurodevelopmental disorders in children eight to 12 years of age.

METHODS

This is a retrospective case-control study comprising 20 children with evidence of prenatal exposure to intra-amniotic inflammation in the mid-trimester and 20 controls matched for gestational age at amniocentesis and at delivery. Amniotic fluid samples were tested for concentrations of interleukin-6 and C-X-C motif chemokine ligand 10, for bacteria by culture and molecular microbiologic methods as well as by polymerase chain reaction for eight viruses. Neuropsychological testing of children, performed by two experienced psychologists, assessed cognitive and behavioral domains. Neuropsychological dysfunction was defined as the presence of an abnormal score (<2 standard deviations) on at least two cognitive tasks.

RESULTS

Neuropsychological dysfunction was present in 45% (9/20) of children exposed to intra-amniotic inflammation but in only 10% (2/20) of those in the control group (p=0.03). The relative risk (RR) of neuropsychological dysfunction conferred by amniotic fluid inflammation remained significant after adjusting for gestational age at delivery [aRR=4.5 (1.07-16.7)]. Of the 11 children diagnosed with neuropsychological dysfunction, nine were delivered at term and eight of them had mothers with intra-amniotic inflammation. Children exposed to intra-amniotic inflammation were found to have abnormalities in neuropsychological tasks evaluating complex skills, e.g., auditory attention, executive functions, and social skills, whereas the domains of reasoning, language, and memory were not affected in the cases and controls.

CONCLUSIONS

Asymptomatic sterile intra-amniotic inflammation in the mid-trimester of pregnancy, followed by a term birth, can still confer to the offspring a substantial risk for neurodevelopmental disorders in childhood. Early recognition and treatment of maternal immune activation in pregnancy may be a strategy for the prevention of subsequent neurodevelopmental disorders in offspring.

Innate and Adaptive Immune Systems in Physiological and Pathological Pregnancy

The dynamic immunological changes occurring throughout pregnancy are well-orchestrated and important for the success of the pregnancy. One of the key immune adaptations is the maternal immune tolerance towards the semi-allogeneic fetus. In this review, we provide a comprehensive overview of what is known about the innate and adaptive immunological changes in pregnancy and the role(s) of specific immune cells during physiological and pathological pregnancy. Alongside this, we provided details of remaining questions and challenges, as well as future perspectives for this growing field of research. Understanding the immunological changes that occur can inform potential strategies on treatments for the optimal health of the neonate and pregnant individual both during and after pregnancy.

Impact of maternal factors, environmental factors, and race on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex disease with a multifactorial etiology. As the leading cause of intestinal morbidity and mortality among premature infants, many resources are being dedicated to neonatal care and molecular targets in the newborn intestine. However, NEC is heavily influenced by maternal and perinatal factors as well. Given its nature, preventive approaches to NEC are more likely to improve outcomes than new treatment strategies. Therefore, this review focuses on maternal, environmental, and racial factors associated with the development of NEC, with an emphasis on those that may be modifiable to decrease the incidence of the disease.

The Role of Fetal Membranes during Gestation, at Term, and Preterm Labor

During pregnancy, the fetal membranes (i.e., amniochorionic membranes) surround the intrauterine cavity and provide mechanical, immune, and endocrine support to protect the fetus. Though they are a vital component of the intrauterine cavity, the fetal membranes are largely overlooked as an extension of the placenta, leading to a poor understanding of their role during gestation, parturition, or preterm birth. The fetal membranes are comprised of fetal cellular and stromal layers and line up with maternal decidua forming the feto-maternal interface during pregnancy. This interface plays a large role during pregnancy and the induction of term or preterm parturition (e.g., labor). Here we summarize the function of the fetal membranes focusing on their role during gestation at term, and during preterm births.

A single-cell atlas of murine reproductive tissues during preterm labor

Preterm birth, the leading cause of perinatal morbidity and mortality worldwide, frequently results from the syndrome of preterm labor. The best-established causal link to preterm labor is intra-amniotic infection, which involves premature activation of the parturition cascade in the reproductive tissues. Herein, we utilize single-cell RNA sequencing (scRNA-seq) to generate a single-cell atlas of the murine uterus, decidua, and cervix in a model of infection-induced preterm labor. We show that preterm labor affects the transcriptomic profiles of specific immune and non-immune cell subsets. Shared and tissue-specific gene expression signatures are identified among affected cells. Determination of intercellular communications implicates specific cell types in preterm labor-associated signaling pathways across tissues. In silico comparison of murine and human uterine cell-cell interactions reveals conserved signaling pathways implicated in labor. Thus, our scRNA-seq data provide insights into the preterm labor-driven cellular landscape and communications in reproductive tissues.

Preterm labor with intact membranes: a simple noninvasive method to identify patients at risk for intra-amniotic infection and/or inflammation

OBJECTIVE

To develop a noninvasive scoring system to identify patients at high risk for intra-amniotic infection and/or inflammation, which would reduce the need for amniocentesis.

METHODS

This prospective cohort study comprised patients admitted with preterm labor and intact membranes (20-34 weeks of gestation) who underwent a transabdominal amniocentesis and for whom concentrations of quantitative cervical fetal fibronectin and of maternal serum C-reactive protein (CRP) were determined. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms. Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. Multivariate logistic regression analysis was performed to identify intra-amniotic infection/inflammtion with noninvasive parameters that had a significant relationship with univariate analysis. With four parameters identified by multivariate analysis, we generated a noninvasive risk scoring system.

RESULTS

Of the study population consisting of 138 singleton pregnant women, (1) the overall rate of intra-amniotic infection/inflammation was 28.3% (39/138); (2) four parameters were used to develop a noninvasive risk scoring system [i.e. cervical fetal fibronectin concentration (score 0-2), maternal serum CRP concentration (score 0-2), cervical dilatation (score 0-2), and gestational age at presentation (score 0-1)]; the total score ranges from 0 to 7; 3) the area under the curve of the risk score was 0.96 (95% confidence interval (CI), 0.92-0.99), significantly higher than that of each predictor in the identification of intra-amniotic infection/inflammation (p < .001, for all); 4) the risk score with a cutoff of 4 had a sensitivity of 94.9% (37/39), a specificity of 90.9% (90/99), a positive predictive value of 80.4% (37/46), a negative predictive value of 97.8% (90/92), a positive likelihood ratio of 10.4 (95% CI, 5.6-19.5), and a negative likelihood ratio of 0.06 (95% CI, 0.15-0.22) in the identification of intra-amniotic infection/inflammation.

CONCLUSIONS

(1) The combination of four parameters (concentrations of cervical fetal fibronectin and maternal serum CRP, cervical dilatation, and gestational age) was independently associated with intra-amniotic infection and/or inflammation; and (2) the risk scoring system comprised of the combination of 4 noninvasive parameters was sensitive and specific to identify the patients at risk for intra-amniotic infection and/or inflammation.

Maternal Origins of Neonatal Infections: What Do Obstetrician-Gynecologist Should/Could Do?

Neonatal infections are responsible for 20% of neonatal deaths yearly. In this review, we focused on the origins of the commoner neonatal infections, and we define the role of obstetricians. Regarding group B Streptococcus, a key measure for the prevention of neonatal infection is the vaginal-rectal culture screening at term pregnancy. Intravenous penicillin is the first-line prophylaxis at the start of labor, with intravenous ampicillin as an alternative. First-generation cephalosporins or clindamycin are recommended in case of penicillin allergy. Concerning urinary tract infections (UTIs), guidelines recommend complete urinalysis and urine culture in the first trimester of pregnancy for the screening of asymptomatic bacteriuria. For lower UTIs, guidelines recommend nitrofurantoin as first-choice antibiotic. Amoxicillin or cefalexin are second-line antibiotics. For upper UTIs, guidelines recommend cephalexin per os as first line. Candida spp. colonization affects 20% of pregnant women; however, congenital fetal candidosis and Candida amnionitis are rare. First-line treatment in case of symptomatic vaginitis during pregnancy or asymptomatic colonization during the third trimester is vaginal clotrimazole. Fluconazole is not approved in pregnancy, especially during the first trimester. Genital mycoplasmas colonization during pregnancy is usually asymptomatic and associated with bacterial vaginosis. Colonization is related to neonatal respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), pneumonia, chorioamnionitis, and sepsis. Macrolides are the first-line treatment along with lactobacillus supplementation. In cases of preterm premature rupture of membranes or preterm labor, ceftriaxone, clarithromycin, and metronidazole are required to prevent intra-amniotic infection. Intra-amniotic infection affects 1 to 5% of deliveries at term and one-third of preterm ones and is associated with perinatal death, early-onset neonatal sepsis, RDS, BPD, pneumonia, meningitis, and prematurity-related diseases. Guidelines recommend a combination of ampicillin and gentamicin, and in case of caesarean section, an additional dose of clindamycin or metronidazole is required. In conclusion, obstetricians should be aware that the treatment of maternal infection during pregnancy can prevent potentially lethal infections in the newborn. KEY POINTS: · Part of neonatal infections starts from maternal infections that must be treated during pregnancy.. · Streptococcus group B and asymptomatic bacteriuria should be investigated in pregnancy and treated.. · Mycoplasma and ureaplasma vaginal colonization during pregnancy is related to negative neonatal outcomes..

Resolution of acute cervical insufficiency after antibiotics in a case with amniotic fluid sludge

Cervical insufficiency generally refers to a condition in which there is mid-trimester cervical dilatation or protruding chorioamniotic membranes in the absence of uterine contractions. Such condition is a risk factor for spontaneous mid-trimester abortion or early preterm birth, and is associated with adverse neonatal outcomes. Both intra-amniotic infection and inflammation ascertained by amniocentesis have been identified in patients with cervical insufficiency, and are poor prognostic factors. A subset of patients with intra-amniotic inflammation will have no demonstrable microorganisms detected via cultivation or molecular methods, and therefore represent cases of sterile intra-amniotic inflammation. Amniotic fluid sludge (free-floating hyperechogenic material within the amniotic fluid in close proximity to the uterine cervix) identified on sonography is a biomarker for intra-amniotic infection and inflammation. Recent evidence suggests that intra-amniotic infection, as well as sterile intra-amniotic inflammation can be treated successfully using antimicrobial agents. We report a unique case in which administration of antibiotics in the presence of mid-trimester cervical insufficiency, sterile intra-amniotic inflammation, and amniotic fluid sludge was associated with resolution of the cervical findings, as demonstrated on both sonographic and speculum examination. The patient successfully underwent elective cesarean delivery at 36-2/7 weeks of gestation. This case illustrates that antibiotic therapy may be effective despite the presence of several high-risk pregnancy conditions, and that successful outcome is possible.

IL-6 and IL-8: An Overview of Their Roles in Healthy and Pathological Pregnancies

Interleukin-6 (IL-6) is an acknowledged inflammatory cytokine with a pleiotropic action, mediating innate and adaptive immunity and multiple physiological processes, including protective and regenerative ones. IL-8 is a pro-inflammatory CXC chemokine with a primary function in attracting and activating neutrophils, but also implicated in a variety of other cellular processes. These two ILs are abundantly expressed at the feto-maternal interface over the course of a pregnancy and have been shown to participate in numerous pregnancy-related events. In this review, we summarize the literature data regarding their role in healthy and pathological pregnancies. The general information related to IL-6 and IL-8 functions is followed by an overview of their overall expression in cycling endometrium and at the feto-maternal interface. Further, we provide an overview of their involvement in pregnancy establishment and parturition. Finally, the implication of IL-6 and IL-8 in pregnancy-associated pathological conditions, such as pregnancy loss, preeclampsia, gestational diabetes mellitus and infection/inflammation is discussed.

Do the Causes of Spontaneous Preterm Delivery Affect Placental Inflammatory Pathology and Neonatal Outcomes?

Objective: To investigate the severity of histologic chorioamnionitis /funisitis according to the indication for preterm delivery and their corresponding neonatal outcomes. Method: This study included 411 singleton women who delivered between 21+0 and 31+6 week of gestation due to preterm labor (PTL, n = 165), preterm premature rupture of membranes (PPROM, n = 202), or incompetent internal os of the cervix (IIOC, n = 44). The primary outcome measure was the rate of severe histological chorioamnionitis/funisitis. Secondary outcome measure was neonatal outcomes including neonatal and infant death, and neonatal composite morbidity. Results: The PPROM group demonstrated a higher rate of severe histological chorioamnionitis/funisitis compared to the PTL group (severe histological chorioamnionitis; PPROM, 66.3% vs. PTL, 49.1%, p = 0.001, severe funisitis; PPROM, 44.1% vs. PTL, 23.6%, p < 0.001) and this remained significant after multivariable analysis (severe histologic chorioamnionitis, OR 2.367, 95% CI 1.517−3.693; severe funisitis, OR 2.668, 95% CI 1.684−4.226). For neonatal outcomes only, a higher rate of patent ductus arteriosus was observed in the IIOC group compared to the PTL and PPROM groups (IIOC, 77.3% vs. PTL, 54.0% vs. PPROM, 54.0%, p = 0.043) and this remained significant after multivariable analysis. Conclusion: Indication of spontaneous preterm delivery might affect the placental inflammatory pathology and neonatal morbidity.

Preterm Labor and Preterm-PROM at a Lower Gestational Age Are Associated with a Longer Latency-to-Delivery Even in Patients with the Same Intensity of Intra-Amniotic Inflammation: "Carroll-Model" Revisited

A previous study by Carroll et al. demonstrated that the time from preterm-PROM to delivery was longer at a lower gestational age (GA) when the membranes rupture, although the presence or absence of intra-amniotic inflammation (IAI) was not examined in that study. However, patients with either preterm labor (PTL) or preterm-PROM at a lower GA had more frequent IAI, which was associated with a shorter amniocentesis-to-delivery (ATD) interval as compared with inflammation-free amniotic fluid (AF). Up to now, there is no information about whether PTL and preterm-PROM at a lower GA are associated with a shorter or longer latency to delivery in cases with the same intensity of IAI. The objective of the study is to examine this issue. AF MMP-8 was measured in 476 singleton early preterm-gestations (21.5 < GA at amniocentesis < 34 wks) with PTL (n = 253) and preterm-PROM (n = 223). Patients were divided into three groups according to GA at amniocentesis (i.e., group-1: <26 wks; group-2: 26−30 wks; group-3: 30−34 wks). IAI was defined as an elevated AF MMP-8 (≥23 ng/mL), and IAI was classified into either mild IAI (AF MMP-8: 23−350 ng/mL) or severe IAI (AF MMP-8 ≥ 350 ng/mL). ATD interval was examined according to GA at amniocentesis in the context of the same intensity of IAI (i.e., inflammation-free AF, mild IAI, and severe IAI) among pregnant women with either PTL or preterm-PROM. IAI was more frequent at a lower GA in cases with PTL (group-1 vs. group-2 vs. group-3; 59.5% vs. 47.4% vs. 25.1%; X2test, p = 0.000034 and linear by linear association [LBLA], p = 0.000008) and in those with preterm-PROM (group-1 vs. group-2 vs. group-3; 69.2% vs. 50.0% vs. 32.0%; X2test, p = 0.000104, and LBLA, p = 0.000019). Of note, cases without IAI at a lower GA had a longer ATD interval in both PTL (Spearman’s rank correlation test, γ = −0.360, p = 0.000003) and preterm-PROM (γ = −0.570, p = 0.000001) groups. Moreover, the lower the GA, the longer the ATD interval, even among patients with mild and severe IAI in both PTL (Spearman’s rank correlation test; mild IAI, γ = −0.290, p = 0.039; severe IAI, γ = −0.299, p = 0.048) and preterm-PROM (mild IAI, γ = −0.565, p = 0.000013; severe IAI, γ = −0.363, p = 0.015) groups. In conclusion, PTL and preterm-PROM at a lower GA are associated with a longer latency to delivery, even in patients with the same intensity of IAI. This finding suggests that a more intense IAI may be needed for spontaneous preterm birth at a lower GA.

The amniotic fluid proteome predicts imminent preterm delivery in asymptomatic women with a short cervix

Preterm birth, the leading cause of perinatal morbidity and mortality, is associated with increased risk of short- and long-term adverse outcomes. For women identified as at risk for preterm birth attributable to a sonographic short cervix, the determination of imminent delivery is crucial for patient management. The current study aimed to identify amniotic fluid (AF) proteins that could predict imminent delivery in asymptomatic patients with a short cervix. This retrospective cohort study included women enrolled between May 2002 and September 2015 who were diagnosed with a sonographic short cervix (< 25 mm) at 16-32 weeks of gestation. Amniocenteses were performed to exclude intra-amniotic infection; none of the women included had clinical signs of infection or labor at the time of amniocentesis. An aptamer-based multiplex platform was used to profile 1310 AF proteins, and the differential protein abundance between women who delivered within two weeks from amniocentesis, and those who did not, was determined. The analysis included adjustment for quantitative cervical length and control of the false-positive rate at 10%. The area under the receiver operating characteristic curve was calculated to determine whether protein abundance in combination with cervical length improved the prediction of imminent preterm delivery as compared to cervical length alone. Of the 1,310 proteins profiled in AF, 17 were differentially abundant in women destined to deliver within two weeks of amniocentesis independently of the cervical length (adjusted p-value < 0.10). The decreased abundance of SNAP25 and the increased abundance of GPI, PTPN11, OLR1, ENO1, GAPDH, CHI3L1, RETN, CSF3, LCN2, CXCL1, CXCL8, PGLYRP1, LDHB, IL6, MMP8, and PRTN3 were associated with an increased risk of imminent delivery (odds ratio > 1.5 for each). The sensitivity at a 10% false-positive rate for the prediction of imminent delivery by a quantitative cervical length alone was 38%, yet it increased to 79% when combined with the abundance of four AF proteins (CXCL8, SNAP25, PTPN11, and MMP8). Neutrophil-mediated immunity, neutrophil activation, granulocyte activation, myeloid leukocyte activation, and myeloid leukocyte-mediated immunity were biological processes impacted by protein dysregulation in women destined to deliver within two weeks of diagnosis. The combination of AF protein abundance and quantitative cervical length improves prediction of the timing of delivery compared to cervical length alone, among women with a sonographic short cervix.

Defining a role for Interferon Epsilon in normal and complicated pregnancies

Interferon epsilon (IFNe) is a recently described cytokine that is constitutively expressed in the female reproductive tract. However, the role of this hormonally regulated cytokine during human pregnancy is poorly understood. Moreover, whether IFNe participates in host immune response against bacteria-driven intra-amniotic infection or cervical human papillomavirus infection during pregnancy is unknown. Herein, using a unique set of human samples derived from multiple study cohorts, we aimed to uncover the role of IFNe in normal and complicated pregnancies. We showed that IFNe is expressed in the myometrium, cervix, and chorioamniotic membranes, and may therefore represent a constitutive element of host defense mechanisms in these tissues during pregnancy. The expression of IFNe in the myometrium and cervix appeared greater in late gestation than in mid-pregnancy, but did not seem to be impacted by labor. Notably, concentrations of IFNe in amniotic fluid, but not cervical fluid, were increased in a subset of women undergoing spontaneous preterm labor with intra-amniotic infection, indicating that IFNe could participate in anti-microbial responses in the amniotic cavity. However, stimulation with Ureaplasma parvum and/or lipopolysaccharide did not enhance IFNE expression by amnion epithelial or cervical cells in vitro, implicating alternative sources of this cytokine during intra-amniotic or cervical infection, respectively. Collectively, our results represent the first characterization of IFNe expression by human reproductive and gestational tissues during normal pregnancy and suggest a role for this cytokine in intra-amniotic infection leading to preterm birth.

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Lamellar body count: Marker for foetal lung maturation promoted by intra-amniotic infection and/or inflammation

OBJECTIVE

There is evidence indicating that the risk of respiratory distress syndrome is reduced in preterm neonates exposed to intra-amniotic infection and/or inflammation. We hypothesised that foetal lung maturation promoted by intra-amniotic infection and/or inflammation results in elevated lamellar body count (LBC) in amniotic fluid (AF). This study aimed to determine the relationship between LBC in AF and intra-amniotic infection and/or inflammation in patients with threatened preterm birth.

STUDY DESIGN

This was a retrospective cohort study of patients with threatened preterm birth. A total of 104 consecutive pregnant women underwent amniocentesis in the early preterm period [gestational age < 34 weeks] to evaluate intra-amniotic infection and/or inflammation and foetal lung maturity. Intra-amniotic infection was confirmed by positive AF culture results for aerobic/anaerobic bacteria, fungi, and genital mycoplasma. Intra-amniotic inflammation was defined as a positive AF matrix metalloproteinase-8 rapid test. Outcomes of the study population were compared according to LBC in AF using a cut-off of 15,000/mm³.

RESULTS

The rates of elevated LBC and intra-amniotic infection and/or inflammation were 23% (24/104) and 52% (54/104), respectively. The median LBC was significantly higher in patients with intra-amniotic infection and/or inflammation than in those without [median LBC, 9,000/mm³ (interquartile range, IQR: 3,000-39,000) vs. 3,000/mm³ (IQR: 2,750-5,000), p < 0.001]. Intra-amniotic infection and/or inflammation was observed in 96% (23/24) of patients with elevated LBC and 39% (31/80) of patients without elevated LBC (p < 0.001). On multivariable analysis, the presence of intra-amniotic infection and/or inflammation was significantly associated with elevated LBC with an odds ratio (OR) of 66.0 [95% confidence interval (CI) 6.6-664.4, p < 0.001], even after accounting for gestational age at amniocentesis being a significantly related factor for predicting elevated LBC with an OR of 1.5 (95% CI 1.1-2.0, p = 0.004).

CONCLUSION

LBC elevation was independently associated with the presence of intra-amniotic infection and/or inflammation in women with early threatened preterm birth (gestational age < 34 weeks). This finding may support the view that an intra-amniotic inflammatory response promotes foetal lung maturation that can be detected by elevated LBC in AF.

Inflammatory Proteins in the Amniotic Fluid, Plasma, and Cervicovaginal Fluid for the Prediction of Intra-Amniotic Infection/Inflammation and Imminent Preterm Birth in Preterm Labor

OBJECTIVE

This study was aimed to develop models using multiple cytokine/chemokine levels in cervicovaginal fluid (CVF) and plasma and widely used noninvasive parameters that have better accuracy for predicting intra-amniotic infection and/or inflammation (IAI) and imminent spontaneous preterm delivery (SPTD, ≤48 hours) in women with preterm labor (PTL).

STUDY DESIGN

This was a retrospective cohort study of 95 singleton pregnant women with PTL (23-34 weeks) who underwent amniocentesis. Both CVF and plasma samples were obtained at the time of amniocentesis, and serum C-reactive protein (CRP) levels were measured. The amniotic fluid (AF), CVF, and plasma samples were assayed for interleukin (IL)-6, IL-8, IL-10, monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1β (MIP-1β) levels using a multiplex immunoassay kit.

RESULTS

The levels of most cytokines/chemokines measured in the AF and CVF were significantly higher in the women with than in those without IAI and imminent SPTD, whereas only high-plasma IL-10 level showed a significant association with imminent SPTD. In predicting IAI, proteins in AF had significantly higher areas under the curves (AUCs) than those in CVF and plasma. However, for predicting imminent SPTD, no significant differences in the AUCs of the outcome-associated proteins were observed among the measurements in AF, CVF, and maternal plasma. By using stepwise regression analyses, noninvasive models (using protein levels in CVF and baseline clinical parameters) were developed for the prediction of IAI and imminent SPTD. The AUC of these noninvasive models were similar to those of the invasive models (using AF protein levels and baseline clinical parameters).

CONCLUSION

Noninvasive models based on CVF cytokine/chemokine levels and widely used noninvasive parameters (especially CRP) act as good indicators for predicting the risk of IAI and imminent SPTD in women with PTL. Evaluation of cytokine/chemokine levels in plasma samples did not add valuable information regarding the two outcome measures in the PTL setting.

KEY POINTS

· Markers in either CVF or plasma alone did not have sufficient accuracy for predicting IAI and SPTD.. · Noninvasive models using CVF cytokine and CRP act as effective tools for predicting two outcomes.. · Evaluation of cytokine level in plasma did not add valuable information regarding two outcomes..