Cytokines in noninvasively obtained amniotic fluid as predictors of fetal inflammatory response syndrome

Correlation of amniotic fluid inflammatory markers with preterm birth: a meta-analysis

BACKGROUND

The relationship between amniotic fluid inflammatory biomarkers and preterm birth in second- or third-trimester pregnancy has been a focus, and understanding the correlation between these markers and preterm birth is important for early identification and intervention in preterm birth. The aim of this study was to explore potential inflammatory biomarkers in second- or third-trimester pregnancy amniotic fluid associated with preterm birth.

METHODS

On November 30, 2023, we searched literature involved the influence of second- or third-trimester pregnancy amniotic fluid inflammatory biomarkers on preterm birth through PubMed, Web of Science, Embase, Scope, CNKI, WanFang, VIP and China Biomedical Databases. The search languages were Chinese and English. Included outcomes indexes were combined utility analysis via R software.

RESULTS

A total of 11 articles were included in the combined utility analysis. This combined analysis revealed significant differences in several inflammatory biomarkers in amniotic fluid between the two groups (MD = 6.87, 95%CI: 0.26 - 13.47, P < 0.01); the difference in amniotic fluid IL-6 between the two groups (MD = 5.73, 95%CI: 3.13-8.32, P < 0.01); the difference in amniotic fluid IL-10 between the two groups (MD = 0.11, 95%CI: -3.26-3.48, P < 0.01); the difference in amniotic fluid CRP between the two groups (MD = 21.34, 95%CI: 11.69-30.89, P < 0.01); the difference in amniotic fluid MCP-1 between the two groups (MD = 312.14, 95%CI: 211.34-412.97, P < 0.01); the difference in the amniotic fluid MMP-9 between the two groups (MD = 0.86, 95%CI: -0.10-1.82, P < 0.01); and the difference in TNF-α in amniotic fluid between the two groups (MD = 22.78, 95%CI: -5.05-50.61, P < 0.01).

CONCLUSIONS

The inflammatory biomarkers IL-1β, IL-6, IL-10, CRP, TNFα, MCP-1 and MMP-9 in the amniotic fluid of patients in the second- or third-trimester pregnancy were all correlated with preterm birth.

Maternal biomarkers in predicting neonatal sepsis after preterm premature rupture of membranes in preterm infants

AIM

This retrospective cohort study aimed to assess the utility of maternal C-reactive protein (CRP) and leukocyte levels in predicting neonatal sepsis after preterm premature rupture of membranes (pPROM).

METHODS

We conducted a retrospective cohort study (2009-2021), encompassing preterm infants born ≤29 + 6 weeks of gestation following pPROM. The primary outcome was early-onset neonatal sepsis within the initial 72 h of life.

RESULTS

We analysed data from 706 patients with a median gestational age at pPROM of 25.1 weeks and a median gestational age at birth of 26.4 weeks. Overall survival rate was 86.1%, with 65.7% survival without severe morbidities. These rates were significantly worse in preterm infants with sepsis. Maternal CRP and leukocyte levels correlated significantly with neonatal infection markers and sepsis. However, their predictive values, correlation coefficients, and area under the curve values were generally low. Using maternal CRP ≥2 mg/dL to predict neonatal sepsis yielded a positive predictive value of 18.5%, negative predictive value of 91.5%, AUC of 0.589, 45.5% sensitivity, and 74.5% specificity.

CONCLUSION

Maternal CRP and leukocyte levels were ineffective as a tool for predicting early-onset neonatal sepsis following early pPROM. Consequently, these biomarkers lack the reliability required for clinical decision-making in this context.

Soluble urokinase plasminogen activator receptor in vaginally collected amniotic fluid predicting fetal inflammatory response syndrome: a prospective cohort study

BACKGROUND

Improving noninvasive antenatal diagnosis of fetal inflammatory response syndrome (FIRS) can assist in the evaluation of prenatal risk and reduce perinatal outcomes. This study aimed to determine whether soluble urokinase-type plasminogen activator receptor (suPAR) in vaginally collected amniotic fluid is significant in identifying FIRS after preterm premature rupture of membranes before 34 weeks of gestation.

METHODS

This was a prospective cohort study of 114 pregnant women and their newborns after preterm premature rupture of membranes at 22-34+6 weeks of gestation. SuPAR was evaluated using an enzyme-linked immunosorbent assay in vaginally collected amniotic fluid. Patients were classified according to the presence or absence of FIRS. FIRS was defined by umbilical cord blood interleukin-6 level > 11 pg/mL or histological funisitis. The data were analyzed using the R package (R-4.0.5).

RESULTS

SuPAR was detected in all amniotic fluid samples with a median of 26.23 ng/mL (interquartile range (IQR), 15.19-51.14). The median level of suPAR was higher in the FIRS group than in the non-FIRS group, 32.36 ng/mL (IQR, 17.27-84.16) vs. 20.46 ng/mL (IQR, 11.49-36.63) (P = 0.01), respectively. The presence of histological chorioamnionitis significantly increased the suPAR concentration in the FIRS group (P < 0.001). The areas under the curve for FIRS and FIRS with histological chorioamnionitis were 0.65 and 0.74, respectively, with an optimum cutoff value of 27.60 ng/mL. Controlling for gestational age, the cutoff of suPAR more than 27.60 ng/mL predicted threefold higher odds for FIRS and sixfold higher odds for FIRS with histologic chorioamnionitis.

CONCLUSION

Soluble urokinase-type plasminogen activator receptor in vaginally obtained amniotic fluid may assist in evaluating prenatal risk of FIRS in patients after preterm premature rupture of membranes before 34 weeks of gestation.

Statement of the Obstetrics and Prenatal Medicine Working Group (AGG - Preterm Birth Section) on "Outpatient Management for Pregnant Women with Preterm Premature Rupture of Membranes (PPROM)"

Preterm premature rupture of membranes (PPROM) is one of the leading causes of perinatal morbidity and mortality. After a PPROM, more than 50% of pregnant women are delivered within 7 days. Fetal and maternal risks are primarily due to infection and inflammation, placental abruption, umbilical cord complications and preterm birth. Standard care usually consists of an expectant approach. Management includes the administration of antenatal steroids and antibiotic therapy. Patients with PPROM require close monitoring. The management of pregnant women with PPROM (inpatient vs. outpatient) is still the subject of controversial debate. The international guidelines also do not offer a clear stance. The statement presented here discusses the current state of knowledge.

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, September 2022) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and on the Management of Preterm Premature Rupture of Membranes

Aim The revision of this guideline was coordinated by the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (OEGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of the guideline is to improve the prediction, prevention and management of preterm birth based on evidence from the current literature, the experience of members of the guidelines commission, and the viewpoint of self-help organizations. Methods The members of the contributing professional societies and organizations developed recommendations and statements based on international literature. The recommendations and statements were presented and adopted using a formal process (structured consensus conferences with neutral moderation, written Delphi vote). Recommendations Part 2 of this short version of the guideline presents statements and recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

Diagnostic accuracy of amniotic fluid interleukin-6 for fetal inflammatory response syndrome

AIM

This study aimed to clarify the diagnostic accuracy of amniotic fluid interleukin-6 for fetal inflammatory response syndrome (FIRS).

METHODS

This retrospective cohort study was conducted in a single institution and targeted cases of preterm birth within 24 h after amniocentesis among singleton cases that underwent amniocentesis at our hospital for suspected intraamniotic inflammation (IAI) from gestational ages of 22-36 weeks between August 2014 and March 2020. FIRS was defined as >11.0 pg/mL of umbilical cord blood interleukin-6.

RESULTS

The analysis included 158 pregnant women. There was a strong correlation between amniotic fluid interleukin-6 and umbilical cord blood interleukin-6 (r = 0.70, p < 0.001). The area under the receiver operating characteristic curve of amniotic fluid interleukin-6 for FIRS was 0.93, with a cutoff value of 15.5 ng/mL, and showed high sensitivity and specificity (0.91 and 0.88, respectively). An amniotic fluid interleukin-6 cutoff value of ≥15.5 ng/mL was associated with a significant risk of FIRS (adjusted odds ratio: 27.9; 95% confidence interval: 6.3-123.0; p < 0.001).

CONCLUSIONS

The results of this study show that amniotic interleukin 6 alone can be used to diagnose FIRS prenatally. While there is a need for validation, it may be possible to treat IAI while preventing damage to the central nervous and respiratory systems in the uterus by keeping the amniotic fluid interleukin-6 below the cutoff value.

Contribution of Fetal Inflammatory Response Syndrome (FIRS) with or without Maternal-Fetal Inflammation in The Placenta to Increased Risk of Respiratory and Other Complications in Preterm Neonates

This study classifies fetal inflammatory response syndrome (FIRS) based on the presence or absence of maternal-fetal inflammation in the placenta and clarifies the association of FIRS with neonatal morbidities. Women (330) who delivered at gestational ages of 22w0d-33w6d were enrolled and grouped into four based on FIRS and maternal/fetal inflammatory response (MIR/FIR) statuses: Group A: without FIRS and MIR/FIR (reference group); Group B: MIR/FIR alone; Group C: FIRS and MIR/FIR; and Group D: FIRS without MIR/FIR. The associations between bronchopulmonary dysplasia (BPD), adverse neonatal outcomes, extremely low gestational age and Groups B, C, and D were investigated after adjustment for potential confounders. Among patients with FIRS, 29% were in Group D. The risk of BPD was increased in Groups C (adjusted odds ratio (aOR): 3.36; 95% confidence interval (CI): 1.14-9.89) and D (aOR: 4.17; 95% CI: 1.03-16.9), as was the risk of adverse neonatal outcomes (Group C: aOR: 7.17; 95% CI: 2.56-20.1; Group D: aOR: 6.84; 95% CI: 1.85-25.2). The risk of extremely low gestational age was increased in Group D (aOR: 3.85; 95% CI: 1.56-9.52). Therefore, FIRS without MIR/FIR is not rare and may be associated with neonatal morbidities more than FIRS and MIR/FIR.

The Molecular and Histopathological Assessment of Inflammatory Status in Very and Extremely Premature Infants: A Prospective Study

Prematurity comes with a varying range of complications, implying a high prevalence of complications and mortality and depending on the severity of prematurity and the sustained inflammation among these infants, which recently sparked an important scientific interest. The primary objective of this prospective study was to establish the degree of inflammation in very (VPIs) and extremely preterm infants (EPIs) in association with the histology findings of the umbilical cord (UC), while the secondary objective was to study the inflammatory markers in the neonates' blood as predictors of fetal inflammatory response (FIR). A total of thirty neonates were analyzed, ten of them being born extremely premature (<28 weeks of gestation) and twenty very premature (28-32 weeks of gestation). The EPIs had considerably higher levels of IL-6 at birth than VPIs (638.2 pg/mL vs. 151.1 pg/mL). The CRP levels at delivery did not vary substantially across groups; however, after days, the EPIs had significantly higher CRP levels (11.0 mg/dL vs. 7.2 mg/dL). In contrast, the LDH was considerably higher in the extremely preterm infants at birth and four days after birth. Surprisingly, the proportions of infants with pathologically increased inflammatory markers did not differ between the EPIs and VPIs. The LDH increased considerably in both groups, although the CRP levels increased exclusively among the VPIs. The stage of inflammation in the UC did not vary substantially between the EPIs and VPIs. The majority of infants were identified with Stage 0 UC inflammation (40% in EPI vs. 55% in VPIs). There was a substantial correlation link between gestational age and newborn weight and a significant inverse correlation among gestational age and IL-6 and LDH levels. There was a strong negative association between weight and IL-6 (rho = -0.349) and LDH (rho = -0.261). The stage of the UC inflammation demonstrated a statistically significant direct connection with IL-6 (rho = 0.461) and LDH (rho = 0.293), but none with the CRP. Further studies involving a bigger population size of preterm newborns are required to validate the findings and analyze more inflammatory markers, while prediction models on inflammatory markers that are measured expectantly, before the onset of preterm labor, need to be created.

The significance of TNF-α and MMP-8 concentrations in non-invasively obtained amniotic fluid predicting fetal inflammatory response syndrome

OBJECTIVE

To determine the significance of tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-8 (MMP-8) in vaginally obtained amniotic fluid predicting fetal inflammatory response syndrome (FIRS) after preterm premature rupture of membranes (PPROM).

METHODS

In this prospective case-control study, TNF-α and MMP-8 concentrations were evaluated in vaginally obtained amniotic fluid from women with PPROM at 22-34 weeks of pregnancy. Biomarkers' concentrations were determined using an enzyme-linked immunosorbent assay. Patients were divided into two groups: the FIRS group (cord blood interleukin-6 > 11 pg/ml or histological funisitis) and the non-FIRS group (without these findings). The data were analyzed using R package (R-4.0.5).

RESULTS

The median TNF-α and MMP-8 concentrations in amniotic fluid from the 145 women included in the study were higher in the FIRS group than in the non-FIRS group. The area under the curve of TNF-α and MMP-8 was 0.77 and 0.75, respectively. The TNF-α concentration cut-off predicting FIRS was 89.20 pg/ml and was 170.76 pg/ml for MMP-8. In regression analysis, MMP-8 concentration was an independent predictor for FIRS. An MMP-8 concentration greater than 170 ng/ml and a TNF-α concentration greater than 89 pg/ml increased the odds of FIRS 7.62 and 14.92 times, respectively.

CONCLUSIONS

MMP-8 and TNF-α concentrations in vaginally obtained amniotic fluid may be good predictors for FIRS after PPROM before 34 weeks of pregnancy. The non-invasive amniotic fluid analysis could be an alternative method to invasive amniocentesis.

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.

Toward a new taxonomy of obstetrical disease: improved performance of maternal blood biomarkers for the great obstetrical syndromes when classified according to placental pathology

BACKGROUND

The major challenge for obstetrics is the prediction and prevention of the great obstetrical syndromes. We propose that defining obstetrical diseases by the combination of clinical presentation and disease mechanisms as inferred by placental pathology will aid in the discovery of biomarkers and add specificity to those already known.

OBJECTIVE

To describe the longitudinal profile of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and the PlGF/sFlt-1 ratio throughout gestation, and to determine whether the association between abnormal biomarker profiles and obstetrical syndromes is strengthened by information derived from placental examination, eg, the presence or absence of placental lesions of maternal vascular malperfusion.

STUDY DESIGN

This retrospective case cohort study was based on a parent cohort of 4006 pregnant women enrolled prospectively. The case cohort of 1499 pregnant women included 1000 randomly selected patients from the parent cohort and all additional patients with obstetrical syndromes from the parent cohort. Pregnant women were classified into six groups: 1) term delivery without pregnancy complications (n=540; control); 2) preterm labor and delivery (n=203); 3) preterm premature rupture of the membranes (n=112); 4) preeclampsia (n=230); 5) small-for-gestational-age neonate (n=334); and 6) other pregnancy complications (n=182). Maternal plasma concentrations of PlGF and sFlt-1 were determined by enzyme-linked immunosorbent assays in 7560 longitudinal samples. Placental pathologists, masked to clinical outcomes, diagnosed the presence or absence of placental lesions of maternal vascular malperfusion. Comparisons between mean biomarker concentrations in cases and controls were performed by utilizing longitudinal generalized additive models. Comparisons were made between controls and each obstetrical syndrome with and without subclassifying cases according to the presence or absence of placental lesions of maternal vascular malperfusion.

RESULTS

1) When obstetrical syndromes are classified based on the presence or absence of placental lesions of maternal vascular malperfusion, significant differences in the mean plasma concentrations of PlGF, sFlt-1, and the PlGF/sFlt-1 ratio between cases and controls emerge earlier in gestation; 2) the strength of association between an abnormal PlGF/sFlt-1 ratio and the occurrence of obstetrical syndromes increases when placental lesions of maternal vascular malperfusion are present (adjusted odds ratio [aOR], 13.6 vs 6.7 for preeclampsia; aOR, 8.1 vs 4.4 for small-for-gestational-age neonates; aOR, 5.5 vs 2.1 for preterm premature rupture of the membranes; and aOR, 3.3 vs 2.1 for preterm labor (all P<0.05); and 3) the PlGF/sFlt-1 ratio at 28 to 32 weeks of gestation is abnormal in patients who subsequently delivered due to preterm labor with intact membranes and in those with preterm premature rupture of the membranes if both groups have placental lesions of maternal vascular malperfusion. Such association is not significant in patients with these obstetrical syndromes who do not have placental lesions.

CONCLUSION

Classification of obstetrical syndromes according to the presence or absence of placental lesions of maternal vascular malperfusion allows biomarkers to be informative earlier in gestation and enhances the strength of association between biomarkers and clinical outcomes. We propose that a new taxonomy of obstetrical disorders informed by placental pathology will facilitate the discovery and implementation of biomarkers as well as the prediction and prevention of such disorders.

The Significance of Epidermal Growth Factor in Noninvasively Obtained Amniotic Fluid Predicting Respiratory Outcomes of Preterm Neonates

Preterm premature rupture of membranes (PPROM) interrupts normal lung development, resulting in neonatal respiratory morbidity. Although post-PPROM risks have been researched, only a few studies have investigated noninvasively obtained amniotic fluid (AF) to predict neonatal outcomes. In this study, we aimed to determine whether epidermal growth factor (EGF) in vaginally-collected AF is a significant predictor of neonatal respiratory outcomes after PPROM. We analyzed EGF in vaginally-obtained AF from 145 women with PPROM at 22−34 weeks of gestation. The following neonatal outcomes were included: respiratory distress syndrome, surfactant need, duration and type of respiratory support, and bronchopulmonary dysplasia. We found that EGF concentration was associated with gestational age, and its medians were lower in neonates with respiratory morbidities than unaffected ones. EGF concentrations gradually declined, the lowest being in the most clinically ill patients. EGF < 35 pg/mL significantly predicted the odds of severe respiratory outcomes. EGF in noninvasively collected AF may be a reliable predictor for respiratory outcomes of preterm neonates with PPROM before 34 weeks of gestation. The results of our study may have implications for further research both in noninvasive amniotic fluid analysis and the management of patients after PPROM.

Longitudinal evaluation of azithromycin and cytokine concentrations in amniotic fluid following one-time oral dosing in pregnancy

To utilize noninvasive collection of amniotic fluid in the setting of preterm premature rupture of membranes (PPROMs) to report the time concentration profile of azithromycin in amniotic fluid over 7 days from a single dose, and evaluate the correlation between azithromycin concentration and inflammatory markers in amniotic fluid. Prospective cohort study of five pregnant patients admitted with PPROMs and treated with a single 1 g oral azithromycin dose. Amniotic fluid was collected from pads and used to quantify azithromycin concentration as well as TNFa, IL-1a, IL-1b, IL-6, IL-8, and IL-10 concentrations. Primary outcome was time/concentration profile of azithromycin in amniotic fluid. Secondary outcome included correlation between azithromycin concentration and cytokine concentrations. Five patients were enrolled. Mean gestational age on admission with PPROM was 27.5 ± 2.3 weeks with a median latency of 7 days (interquartile range [IQR] = 4-13). A median of two samples/day (IQR = 1-3) were collected per participant. Azithromycin was quantified in duplicate; intra-assay coefficient of variation was 17%. Azithromycin concentration was less than 60 ng/ml after day 3. Azithromycin concentration was positively correlated with IL-8 (r = 0.38, p = 0.03), IL1a (r = 0.39, p = 0.03), and IL-1b (r = 0.36, p = 0.04) in amniotic fluid. Azithromycin is detectable in amniotic fluid over 7 days from a single 1 g maternal dose, however, it is not sustained over the range of minimum inhibitory concentration for common genitourinary flora. Based on correlation with specific cytokines, azithromycin penetration in amniotic fluid may relate to maternal monocyte concentration in amniotic fluid in the setting of PPROM.

Diagnostic predictability of miR-4535 and miR-1915-5p expression in amniotic fluid for foetal morbidity of infection

INTRODUCTION

Clinical prediction of foetal inflammatory response syndrome (FIRS) is highly necessary. We have previously reported that miR-4535 and miR-1915-5p are potential biomarkers for severe chorioamnionitis based on the results of microRNA array analysis. Therefore, we evaluated the relationship between foetal morbidity of infection and miR-4535, miR-1915-5p, interleukin (IL)-6, or 16S rDNA copy number levels in amniotic fluid from pregnant women with chorioamnionitis.

METHODS

Amniotic fluid from 57 pregnant women with preterm premature membrane rupture or threatened premature labour were collected. Infants with WBC counts <5000/μL or >20,000/μL, CRP >0.5 mg/mL, or IgM >20 mg/mL at birth received a diagnosis of suspicious foetal infection, and those requiring antibiotic administration for >5 days were considered infected newborns. miR-4535, miR-1915-5p, and IL-6 levels and 16S rDNA copy number were evaluated. Mann-Whitney U test and Dunn's test were used for comparison. The area under the curve (AUC) and Youden index were calculated to examine the diagnostic accuracy of foetal morbidity of infection.

RESULTS

miR-4535, miR-1915-5p, 16S rDNA, and IL-6 were significantly higher in patients with severe chorioamnionitis than in patients with chorionitis or sub-chorionitis (P < 0.05). miR-4535 and miR-1915-5p levels were significantly associated with WBC counts <5000/μL or >20,000/μL, CRP >0.5 mg/mL, or IgM >20 mg/mL (P < 0.05). AUC values of miR-4535 and miR-1915-5p indicated moderate or low accuracy for foetal morbidity of infection, while those of IL-6 and 16S rDNA seemed unreliable.

DISCUSSION

MiR-4535 and miR-1915-5p levels in amniotic fluid may be considered clinically predictive for foetal morbidity of infection.

Current and Emerging Strategies for Prediction and Diagnosis of Prelabour Rupture of the Membranes: A Narrative Review

Prelabour rupture of membranes (PROM) refers to the disruption of foetal membranes before the onset of labour, resulting in the leakage of amniotic fluid. PROM complicates 3% and 8% of preterm and term pregnancies, respectively. Accurate and timely diagnosis is crucial for effective management to prevent adverse maternal- and foetal-outcomes. The diagnosis of equivocal PROM cases with traditional methods often becomes challenging in current obstetrics practice; therefore, various novel biochemical markers have emerged as promising diagnostic tools. This narrative review is sought to review the published data to understand the current and emerging trends in diagnostic modalities in term and preterm pregnancies complicated with PROM and the potential role of various markers for predicting preterm PROM (pPROM) and chorioamnionitis in women with pPROM.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prognostic Markers for Chorioamnionitis: IL-6, TNF-α, and MMP-8 in Vaginally Obtained Amniotic Fluid

Background. Earlier chorioamnionitis diagnosis is crucial to improve maternal and neonatal health outcomes. This study was conducted to evaluate the inlerleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and matrix metalloproteinase 8 (MMP-8) levels in vaginally obtained amniotic fluid to investigate their prognostic value and to determine the most appropriate cut-off values for the prediction of chorioamnionitis. Methods. This case control study included women who were diagnosed with preterm premature rupture of the membranes before 34 weeks of gestation and were admitted to Vilnius University Hospital Santaros Klinikos. Free-leaking amniotic fluid was obtained vaginally with a sterile speculum less than 48h before delivery. Amniotic fluid IL-6, TNF-α, and MMP-8 levels were determined by the Enzyme Linked Immunosorbent Assay. Diagnosis of chorioamnionitis was confirmed by histological examination of the placenta and membranes after delivery. Results. The study included 156 women, 65 patients in the histological chorioamnionitis group (Group I) and 91 in a group without diagnosed histological chorioamnionitis (Group II). The median concentrations of IL-6, MMP-8, and TNF-α in amniotic fluid were statistically significantly higher in Group I than in Group II (p-value < 0.001). The area under the curve of TNF-α and MMP-8 were higher than the area under the curve of IL-6 (0.91, 0.89, and 0.81, respectively). No statistically significant difference was found when comparing the receiver operating characteristic (ROC) curves of TNF-α and MMP-8. The optimum cut-off values for the prediction of chorioamnionitis were found to be 1389.82 pg/mL for IL-6, 21.17 pg/mL for TNF-α, and 172.53 ng/mL for MMP-8. The sensitivity, specificity, positive prognostic value (PPV), and negative prognostic value (NPV) of the IL-6 cut-off for chorioamnionitis were 88%, 70%, 67%, and 89%, respectively. The sensitivity, specificity, PPV, and NPV of the TNF-α cut-off were 88%, 84%, 79%, and 90%, respectively. The sensitivity, specificity, PPV, and NPV of the MMP-8 cut-off were 80%, 87%, 81%, and 86%, respectively. Conclusions. The vaginally obtained amniotic fluid IL-6, MMP-8, and TNF-α seem to be good predictors for chorioamnionitis of patients with preterm premature rupture of membranes before 34 weeks of gestation. The noninvasive technique of sampling amniotic fluid could be alternative method to invasive amniocentesis.

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

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

Maternal environmental enrichment modulates the immune response against an inflammatory challenge during gestation and protects the offspring

The production of pro-inflammatory cytokines during inflammatory processes has been associated with preterm birth (PTB) and fetal injury in humans and mice. We previously demonstrated that exposition to an enriched environment (EE), defined as a noninvasive and biological significant stimulus of the sensory pathway combined with voluntary physical activity, prevented PTB and perinatal death induced by the systemic administration of bacterial lipopolysaccharide (LPS) in mice. This work aimed to analyze whether EE modulates the immune response to the inflammatory process induced by LPS in peripheral blood and the amniotic fluid (AF). We observed that EE modulated maternal white blood cell count and its response to LPS. Furthermore, we found higher levels of IL-10 and a higher percentage of B cells in AF from EE exposed mothers compared to controls. Albeit LPS significantly increased IL-6 levels in AF from both groups, it was 3.6 times higher in control environment (CE) exposed group when compared to EE. Similarly, levels of IL-22 were significantly increased by LPS in both groups, but it was 6.7 times higher in EE group. Interestingly, levels of PGE2 in AF were only increased in the EE-LPS treated group, and a positive correlation between IL-22 and PGE2 levels was observed. During lactation, EE prevented LPS-induced delay in physical landmarks analyzed to assess offspring development. Our results suggest that EE modulates the immune response to systemic LPS-administration protecting the offspring. We propose that an EE-like protocol could be designed for pregnant women aiming at preventing the sequelae present in premature children.

Amniotic fluid Gram stain and interleukin-6 can predict early-onset neonatal sepsis

AIM

To clarify whether amniotic fluid findings (Gram stain and interleukin [IL]-6 level) can predict early-onset neonatal sepsis (EONS) before delivery.

METHODS

We compared the sensitivity and specificity and the values of the area under the receiver-operating characteristic (AUROC) curve of maternal inflammatory responses and amniotic fluid findings using IL-6 and Gram stain to predict EONS. Patients who underwent amniocentesis for suspected intra-amniotic infection (IAI) after 22 weeks and 0 days of gestation and delivered on the same day at our hospital between January 2013 and December 2018 were included.

RESULTS

Out of 200 patients, EONS developed in 9 patients. The AUROC curves of maternal white blood cells count, C-reactive protein and body temperature were low (range, 0.6-0.7), whereas that of amniotic fluid IL-6 was high (0.90). Sensitivity and specificity for amniotic fluid findings were, respectively, 100% and 67% for IL-6 (cut-off value: 17.4 ng/mL) and 100% and 88% for the Gram stain; these values were superior to those of maternal inflammatory responses. When examining the accuracy of the amniotic fluid Gram stain separately before and after 34 gestation weeks, similar results were obtained. Amniotic fluid IL-6 before 34 gestation weeks showed specificity similar to that of the Gram stain; however, there were large differences in cut-off values based on gestational age.

CONCLUSION

Gram stain results of amniotic fluid can predict EONS with high sensitivity and specificity when IAI is suspected. False-negative amniotic fluid Gram stain results can be prevented by measuring amniotic fluid IL-6 simultaneously.

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

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

A new rapid bedside test to diagnose and monitor intraamniotic inflammation in preterm PROM using transcervically collected fluid

BACKGROUND

Microbial invasion of the amniotic cavity, a clinical condition present in approximately 50% of patients with preterm prelabor rupture of membranes, is often associated with intraamniotic inflammation, a risk factor for a short admission-to-delivery interval, early preterm delivery, and neonatal complications. We previously developed a transcervical amniotic fluid collector, the device that allows the collection of fluid noninvasively from the cervical canal when membrane rupture occurs.

OBJECTIVE

This study was designed to determine whether rapid analysis of an interleukin-8 concentration in fluid obtained noninvasively by the transcervical amniotic fluid collector can be used to assess the risk of intraamniotic inflammation. We also compared the diagnostic performance of this point-of-care test for interleukin-8 in transcervically obtained fluid to that of a white blood cell count determined in amniotic fluid retrieved by transabdominal amniocentesis.

STUDY DESIGN

This prospective cohort study was conducted between October 2011 and April 2017. Fluid was retrieved through both transabdominal amniocentesis and the use of a transcervical amniotic fluid collector within 24 hours of amniocentesis in patients with a singleton pregnancy and preterm prelabor rupture of the membranes (16-35 weeks of gestation). Amniotic fluid obtained via amniocentesis was cultured for aerobic and anaerobic bacteria and genital mycoplasmas; a white blood cell count was also measured in amniotic fluid. Intraamniotic infection was diagnosed when microorganisms were identified by the cultivation of amniotic fluid. Intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration (>23 ng/mL) assayed by enzyme-linked immunosorbent assay. Interleukin-8 in cervical fluid obtained by the collector was measured by the point-of-care test that used a test strip and scanner based on the fluorescence immunochromatographic analysis in 2019. The diagnostic indices, predictive values, and likelihood ratios of the 2 different tests were calculated.

RESULTS

First, interleukin-8 concentration ≥9.5 ng/mL in cervical fluid, determined by the point-of-care test, was at the knee of the receiver operating characteristic curve analysis and had a sensitivity of 98% (56/57; 95% confidence interval, 91-99.96%), specificity of 74% (40/54; 95% confidence interval, 60-85%), positive predictive value of 80% (56/70; 95% confidence interval, 72-86%), negative predictive value of 98% (40/41; 95% confidence interval, 85-99.6%), positive likelihood ratio of 3.79 (95% confidence interval, 2.41-5.96), and negative likelihood ratio of 0.02 (95% confidence interval, 0.003-0.17) in the identification of intraamniotic inflammation; a concentration of matrix metalloproteinase-8 >23 ng/mL by enzyme-linked immunosorbent assay had a prevalence of 51% (57/111). Second, a cervical fluid interleukin-8 concentration ≥9.5 ng/mL had significantly higher sensitivity than a transabdominally obtained amniotic fluid white blood cell count (≥19 cells/mm³) in the identification of intraamniotic inflammation (sensitivity: 98% [95% confidence interval, 91-99.96%] vs 84% [95% confidence interval, 72-93%]; P<.05; specificity: 74% [95% confidence interval, 60-85%] vs 76% [95% confidence interval, 62-87%); positive and negative predictive values: 80% [95% confidence interval, 72-86%] and 98% [95% confidence interval, 85-99.6%] vs 79% [95% confidence interval, 69-86%] and 82% [95% confidence interval, 71-89%]) and in the identification of intraamniotic inflammation/infection (gold standard: positive culture for bacteria or a matrix metalloproteinase-8 >23 ng/mL; sensitivity: 91% [95% confidence interval, 82-97%] vs 75% [95% confidence interval, 63-85%]; P<.05).

CONCLUSION

The point-of-care test was predictive of intraamniotic inflammation, based on the determination of interleukin-8 in fluid retrieved by a transcervical amniotic fluid collector. Therefore, the analysis of cervically obtained fluid by such point-of-care test may be used to noninvasively monitor intraamniotic inflammation in patients with preterm prelabor rupture of membranes.

Bacterial Vaginosis: Current Diagnostic Avenues and Future Opportunities

A healthy female genital tract harbors a microbiome dominated by lactic acid and hydrogen peroxide producing bacteria, which provide protection against infections by maintaining a low pH. Changes in the bacterial compositions of the vaginal microbiome can lead to bacterial vaginosis (BV), which is often associated with vaginal inflammation. Bacterial vaginosis increases the risk of acquiring sexually transmitted infections (STIs) like human immunodeficiency virus (HIV) and affects women's reproductive health negatively. In pregnant women, BV can lead to chorioamnionitis and adverse pregnancy outcomes, including preterm premature rupture of the membranes and preterm birth. In order to manage BV effectively, good diagnostic procedures are required. Traditionally clinical and microscopic methods have been used to diagnose BV; however, these methods require skilled staff and time and suffer from reduced sensitivity and specificity. New diagnostics, including highly sensitive and specific point-of-care (POC) tests, treatment modalities and vaccines can be developed based on the identification of biomarkers from the growing pool of vaginal microbiome and vaginal metabolome data. In this review the current and future diagnostic avenues will be discussed.

Intra-amniotic inflammation induces preterm birth by activating the NLRP3 inflammasome†

Intra-amniotic inflammation is strongly associated with spontaneous preterm labor and birth, the leading cause of perinatal mortality and morbidity worldwide. Previous studies have suggested a role for the NLRP3 (NLR family pyrin domain-containing protein 3) inflammasome in the mechanisms that lead to preterm labor and birth. However, a causal link between the NLRP3 inflammasome and preterm labor/birth induced by intra-amniotic inflammation has not been established. Herein, using an animal model of lipopolysaccharide-induced intra-amniotic inflammation (IAI), we demonstrated that there was priming of the NLRP3 inflammasome (1) at the transcriptional level, indicated by enhanced mRNA expression of inflammasome-related genes (Nlrp3, Casp1, Il1b); and (2) at the protein level, indicated by greater protein concentrations of NLRP3, in both the fetal membranes and decidua basalis prior to preterm birth. Additionally, we showed that there was canonical activation of the NLRP3 inflammasome in the fetal membranes, but not in the decidua basalis, prior to IAI-induced preterm birth as evidenced by increased protein levels of active caspase-1. Protein concentrations of released IL1β were also increased in both the fetal membranes and decidua basalis, as well as in the amniotic fluid, prior to IAI-induced preterm birth. Finally, using the specific NLRP3 inhibitor, MCC950, we showed that in vivo inhibition of the NLRP3 inflammasome reduced IAI-induced preterm birth and neonatal mortality. Collectively, these results provide a causal link between NLRP3 inflammasome activation and spontaneous preterm labor and birth in the context of intra-amniotic inflammation. We also showed that, by targeting the NLRP3 inflammasome, adverse pregnancy and neonatal outcomes can be significantly reduced.

A cut-off value for systemic immune-inflammation index in the prediction of adverse neonatal outcomes in preterm premature rupture of the membranes

AIM

To determine a cut-off value for systemic immune-inflammation index (SII)(neutrophil × platelet /lymphocyte) in the prediction of adverse neonatal outcomes in preterm premature rupture of the membranes (PPROM).

METHODS

This retrospective cohort study was conducted among singleton pregnancies with PPROM. Cases were divided into two main groups: Group 1) PPROM diagnosed at 24th-28th weeks of gestation and Group 2) PPROM diagnosed at >28th-34th weeks of gestation. Thereafter, main study groups were divided into two subgroups: Subgroup A: pregnancies with favorable neonatal outcomes and Subgroup B: pregnancies with composite adverse neonatal outcomes. Subgroups were compared in terms of demographic features, clinical characteristics, laboratory test results and SII values. Furthermore, cut-off values of SII for the prediction of composite adverse neonatal outcomes were determined for two main groups. A Mann-Whitney U test was conducted to compare the median values and the chi-square test was used to compare categorical variables among the groups. Receiver operating characteristic (ROC) curves were used to assess the performance of SII value in predicting composite adverse neonatal outcomes.

RESULTS

Significant differences were observed for median platelet and SII values between the subgroups (P < 0.001 for both in group 1 and P = 0.002 and P = 0.005, respectively, in group 2). Cut-off values of 1695.14 10⁹ /L (83.3% sensitivity, 85.7% specificity) and 1430.90 × 10⁹ /L (71.4% sensitivity, 75.7% specificity) for composite adverse neonatal outcomes were determined, respectively in group 1 and 2 according to the ROC curve analysis.

CONCLUSION

SII may be used as an additional indicator for the prediction of adverse neonatal outcomes in PPROM.

Amniotic immune biomarkers as risk factors in women with different symptoms of threatened late miscarriage

PROBLEM

To investigate risk factors that can help identify the possibility of pregnancy loss in threatened late miscarriage (TLM) patients with and without spontaneous uterine contractions.

METHOD OF STUDY

Amniotic immune biomarkers (IL2β receptor, IL6, IL8, IL10, IL1β, and TNFα) were assayed, and "sludge" was assessed. Patients without intrauterine infections were treated and followed up until delivery, and pregnancy outcomes were recorded. The two groups were compared for the differences in biomarker levels and "sludge," and the independent associations of biomarkers, "sludge," and other maternal factors with late miscarriage were investigated.

RESULTS

The amniotic levels of IL2βR, IL8, and TNFα were higher in the group with contractions (P < .05). When considered alone, each of the six biomarkers was significantly associated with late miscarriage in the no-contractions group and four of these (IL8, IL10, IL1β, and TNFα) in the contractions group (P < .05). Biomarker levels were correlated, and in multivariate Cox regression analysis, there was an independent effect only for IL8 in the no-contractions group (HR = 18.16, 95% CI: 5.75-57.43) and TNFα in the contractions group (HR = 4.11, 95% CI: 1.68-10.08). For patients with contractions, IL10, IL8, and IL1β were different in those with and without "sludge," but no such difference was seen in the no-contractions group.

CONCLUSION

For TLM patients without intrauterine infections, amniotic immune biomarkers differ between patients with different symptoms, not only for their levels but also for the impact of these biomarkers on the risk of late miscarriage. These findings suggest that the symptoms of TLM should be considered in the study of miscarriage risk.

Value of cervicovaginal fluid cytokines in prediction of fetal inflammatory response syndrome in pregnancies complicated with preterm premature rupture of membranes (pPROM)

Background Preterm premature rupture of membranes (pPROM) is associated with a high risk of prematurity and complications of fetal inflammatory response syndrome (FIRS). The aim of the study is to determine any correlations between the concentration of selected cytokines contained in the cervicovaginal secretion eluates and in the umbilical cord plasma in patients with pPROM and to find the noninvasive markers of FIRS in order to pinpoint the optimal time of the delivery. Methods The study included 80 patients with pPROM between the 24th and 34th week of gestation. The cervicovaginal fluid and umbilical cord blood were collected. Interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 19 (IL-19) and tumor necrosis factor-α (TNF-α) concentrations were measured in both materials. For the statistical analysis, SigmaStat3.5 software was used. Results There was no direct association in levels of IL-6, TNF-α, IL-10 and IL-19 between the cord blood and cervicovaginal secretions within the studied group. The cut-off point of IL-6 of 26.8 pg/mL in the vaginal fluid had high sensitivity and specificity in order to discriminate between newborns with and without FIRS (81.08%; 76.74%). Conclusion Further studies are needed on a larger group of participants to demonstrate that an elevated concentration of IL-6 above 26.8 pg/mL in the cervicovaginal secretion eluate is an indirect noninvasive marker of FIRS.

The fetal inflammation response syndrome and adverse neonatal outcomes: a meta-analysis

Background: The clinical performance of fetal inflammatory response syndrome (FIRS) is often atypical. The aim of this meta-analysis is to investigate whether FIRS is associated with adverse neonatal outcomes.Methods: PubMed, Embase, and Cochrane Library were used in this study. The adverse neonatal outcomes data including neonatal early-onset sepsis (EOS), bronchopulmonary dysplasia (BPD), periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), respiratory distress syndrome (RDS), and neonatal death were collected to make analysis.Results: A total of 10 articles (1116 patients) were included in this study. Compared to the non-FIRS group, the FIRS group was associated with higher incidence of adverse neonatal outcomes, such as EOS (RR = 3.10, 95% CI: 1.26, 7.65; p=.014), BPD (RR = 5.93, 95% CI = 4.35, 8,08; p < .001), IVH (RR = 4.89, 95% CI = 2.96, 8.08; p < .001), PVL (RR = 3.32, 95% CI: 1.73, 6.40; p < .001), RDS (2.35, 95% CI = 1.67, 3.31; p < .001), and the neonatal death (RR = 7.04, 95% CI: 3.34, 14.85; p < .001).Conclusions: The FIRS is associated with higher incidence of adverse neonatal outcomes, and is a risk factor of severe neonatal morbidity or death.

Cytokine profiles of umbilical cord blood mononuclear cells upon in vitro stimulation with lipopolysaccharides of different vaginal gram-negative bacteria

Inflammatory immune responses induced by lipopolysaccharides (LPS) of gram-negative bacteria play an important role in the pathogenesis of preterm labor and delivery, and in neonatal disorders. To better characterize LPS-induced inflammatory response, we determined the cytokine profile of umbilical cord blood mononuclear cells (UBMC) stimulated with LPS of seven vaginal gram-negative bacteria commonly found in pregnant women with preterm labor and preterm rupture of membrane. UBMC from ten newborns of healthy volunteer mothers were stimulated with purified LPS of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter calcoaceticus, Citrobacter freundii, and Pseudomonas aeruginosa. UBMC supernatants were tested for the presence of secreted pro-inflammatory cytokines (IL-6, IL-1β, TNF), anti-inflammatory cytokine (IL-10), TH₁-type cytokines (IL-12, IFN-γ), and chemokines (IL-8, MIP-1α, MIP-1β, MCP-1) by Luminex technology. The ten cytokines were differentially induced by the LPS variants. LPS of E. coli and E. aerogenes showed the strongest stimulatory activity and P. aeruginosa the lowest. Interestingly, the ability of UBMC to respond to LPS varied greatly among donors, suggesting a strong individual heterogeneity in LPS-triggered inflammatory response.

Vaginal Mycoplasmataceae colonization and association with immune mediators in pregnancy

OBJECTIVE

To determine the prevalence of Mycoplasmataceae species in pregnant women and evaluate their association with immune system mediators.

METHODS

Women were prospectively enrolled between 16-22 weeks' gestation. Vaginal swabs were self-collected and analyzed with PCR for Mycoplasma hominis (MH) and Mycoplasma genitalium (MG) as well as Ureaplasma urealyticum (UU) and Ureaplasma parvum (UP) (collectively, Myc). Immune mediators were measured via Luminex multiplex assay. Women with vaginal Mycoplasmataceae were compared to women without Myc, and women with Mycoplasma species (MH or MG) were compared to women without MH or MG. Linear regression models were used to investigate the relationship of the presence of Mycoplasmataceae on log-transformed immune mediators while controlling for confounders using propensity scores.

RESULTS

One-hundred-twenty women were enrolled and had complete lab data available. Colonization was 20.8, 2.5, 10.0, and 48.3% for MH, MG, UU, and UP, respectively. Women with any Mycoplasmataceae were more likely to be younger, of the Black race, and have public insurance. There were no significant differences in immune mediators between women with vaginal Mycoplasmataceae versus those without. After controlling for confounders, women with MH and/or MG had significantly elevated levels of IL-1β compared to women without MH or MG (estimate =  1.12; 95% CI =  0.33, 1.93). There were no other significant differences in immune mediators in women with MH and/or MG compared to those without.

CONCLUSIONS

Colonization rates were highest for UP and lowest for MG. Higher IL-1β levels were seen in the presence of MH and/or MG, indicating that these less frequently encountered organisms may incite a stronger host response. There were no other significant differences in immune mediator levels.

Prevention and Therapy of Preterm Birth. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/025, February 2019) - Part 2 with Recommendations on the Tertiary Prevention of Preterm Birth and the Management of Preterm Premature Rupture of Membranes

Aims This is an official guideline of the German Society for Gynecology and Obstetrics (DGGG), the Austrian Society for Gynecology and Obstetrics (ÖGGG) and the Swiss Society for Gynecology and Obstetrics (SGGG). The aim of this guideline is to improve the prediction, prevention and management of preterm birth based on evidence obtained from recently published scientific literature, the experience of the members of the guideline commission and the views of self-help groups. Methods The members of the participating medical societies and organizations developed Recommendations and Statements based on the international literature. The Recommendations and Statements were adopted following a formal consensus process (structured consensus conference with neutral moderation, voting done in writing using the Delphi method to achieve consensus). Recommendations Part 2 of this short version of the guideline presents Statements and Recommendations on the tertiary prevention of preterm birth and the management of preterm premature rupture of membranes.

Evidence that antibiotic administration is effective in the treatment of a subset of patients with intra-amniotic infection/inflammation presenting with cervical insufficiency

BACKGROUND

Cervical insufficiency is a risk factor for spontaneous midtrimester abortion or early preterm birth. Intra-amniotic infection has been reported in 8-52% of such patients and intra-amniotic inflammation in 81%. Some professional organizations have recommended perioperative antibiotic treatment when emergency cervical cerclage is performed. The use of prophylactic antibiotics is predicated largely on the basis that they reduce the rate of complications during the course of vaginal surgery. However, it is possible that antibiotic administration can also eradicate intra-amniotic infection/inflammation and improve pregnancy outcome.

OBJECTIVE

To describe the outcome of antibiotic treatment in patients with cervical insufficiency and intra-amniotic infection/inflammation.

STUDY DESIGN

The study population consisted of 22 women who met the following criteria: (1) singleton pregnancy; (2) painless cervical dilatation of >1 cm between 16.0 and 27.9 weeks of gestation; (3) intact membranes and absence of uterine contractions; (4) transabdominal amniocentesis performed for the evaluation of the microbiologic and inflammatory status of the amniotic cavity; (5) presence of intra-amniotic infection/inflammation; and (6) antibiotic treatment (regimen consisted of ceftriaxone, clarithromycin, and metronidazole). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and polymerase chain reaction for Ureaplasma spp. was performed. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms or a positive polymerase chain reaction for Ureaplasma spp., and intra-amniotic inflammation was suspected when there was an elevated amniotic fluid white blood cell count (≥19 cells/mm³) or a positive rapid test for metalloproteinase-8 (sensitivity 10 ng/mL). For the purpose of this study, the "gold standard" for diagnosis of intra-amniotic inflammation was an elevated interleukin-6 concentration (>2.6 ng/mL) using an enzyme-linked immunosorbent assay. The results of amniotic fluid interleukin-6 were not available to managing clinicians. Follow-up amniocentesis was routinely offered to monitor the microbiologic and inflammatory status of the amniotic cavity and fetal lung maturity. Treatment success was defined as resolution of intra-amniotic infection/inflammation or delivery ≥34 weeks of gestation.

RESULTS

Of 22 patients with cervical insufficiency and intra-amniotic infection/inflammation, 3 (14%) had microorganisms in the amniotic fluid. Of the 22 patients, 6 (27%) delivered within 1 week of amniocentesis and the remaining 16 (73%) delivered more than 1 week after the diagnostic procedure. Among these, 12 had a repeat amniocentesis to assess the microbial and inflammatory status of the amniotic cavity; in 75% (9/12), there was objective evidence of resolution of intra-amniotic inflammation or intra-amniotic infection demonstrated by analysis of amniotic fluid at the time of the repeat amniocentesis. Of the 4 patients who did not have a follow-up amniocentesis, all delivered ≥34 weeks, 2 of them at term; thus, treatment success occurred in 59% (13/22) of cases.

CONCLUSION

In patients with cervical insufficiency and intra-amniotic infection/inflammation, administration of antibiotics (ceftriaxone, clarithromycin, and metronidazole) was followed by resolution of the intra-amniotic inflammatory process or intra-amniotic infection in 75% of patients and was associated with treatment success in about 60% of cases.

Artificial intelligence and amniotic fluid multiomics: prediction of perinatal outcome in asymptomatic women with short cervix

OBJECTIVE

To evaluate the application of artificial intelligence (AI), i.e. deep learning and other machine-learning techniques, to amniotic fluid (AF) metabolomics and proteomics, alone and in combination with sonographic, clinical and demographic factors, in the prediction of perinatal outcome in asymptomatic pregnant women with short cervical length (CL).

METHODS

AF samples, which had been obtained in the second trimester from asymptomatic women with short CL (< 15 mm) identified on transvaginal ultrasound, were analyzed. CL, funneling and the presence of AF 'sludge' were assessed in all cases close to the time of amniocentesis. A combination of liquid chromatography coupled with mass spectrometry and proton nuclear magnetic resonance spectroscopy-based metabolomics, as well as targeted proteomics analysis, including chemokines, cytokines and growth factors, was performed on the AF samples. To determine the robustness of the markers, we used six different machine-learning techniques, including deep learning, to predict preterm delivery < 34 weeks, latency period prior to delivery < 28 days after amniocentesis and requirement for admission to a neonatal intensive care unit (NICU). Omics biomarkers were evaluated alone and in combination with standard sonographic, clinical and demographic factors to predict outcome. Predictive accuracy was assessed using the area under the receiver-operating characteristics curve (AUC) with 95% CI, sensitivity and specificity.

RESULTS

Of the 32 patients included in the study, complete omics, demographic and clinical data and outcome information were available for 26. Of these, 11 (42.3%) patients delivered ≥ 34 weeks, while 15 (57.7%) delivered < 34 weeks. There was no statistically significant difference in CL between these two groups (mean ± SD, 11.2 ± 4.4 mm vs 8.9 ± 5.3 mm, P = 0.31). Using combined omics, demographic and clinical data, deep learning displayed good to excellent performance, with an AUC (95% CI) of 0.890 (0.810-0.970) for delivery < 34 weeks' gestation, 0.890 (0.790-0.990) for delivery < 28 days post-amniocentesis and 0.792 (0.689-0.894) for NICU admission. These values were higher overall than for the other five machine-learning methods, although each individual machine-learning technique yielded statistically significant prediction of the different perinatal outcomes.

CONCLUSIONS

This is the first study to report use of AI with AF proteomics and metabolomics and ultrasound assessment in pregnancy. Machine learning, particularly deep learning, achieved good to excellent prediction of perinatal outcome in asymptomatic pregnant women with short CL in the second trimester. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Should the diagnostic criteria for suspected clinical chorioamnionitis be changed?

Purpose of review: The criteria for the diagnosis of intra-amniotic infection (IAI) were derived from a study of women at term in labor but is currently used as the main diagnostic tool for clinical chorioamnionitis. Regarding the inconsistent usage of the term, the diagnostic utility of clinical chorioamnionitis needs to be revisited. In this review, we addressed the critical issues on why the diagnostic criteria of suspected clinical chorioamnionitis should be changed.Recent findings: Overall, the accuracy of clinical chorioamnionitis to detect intra-amniotic infection (IAI) is not high, around 50%. The accuracy of each diagnostic criteria to diagnose IAI is, for example, 51.1% with maternal tachycardia, 57.8% with fetal tachycardia, and 55.6% with maternal leukocytosis. However, it needs to be reminded that these diagnostic performances had been obtained from term pregnancies but not from preterm pregnancies. Since there is a difference between clinical chorioamnionitis and histologic chorioamnionitis or even IAI, the diagnostic criteria of clinical chorioamnionitis would be ideal if it could directly predict the development of neonatal infectious outcomes. In fact, multiple definitions of clinical chorioamnionitis either in more lenient or stringent manner are currently used, which is responsible for inconsistent association of clinical chorioamnionitis with long-term neonatal outcomes. Whereas the diagnosis of clinical chorioamnionitis in preterm is followed by expeditious delivery, the diagnosis of clinical chorioamnionitis at term pregnancy is usually conducted in laboring women and requires additional neonatal evaluation for sepsis, which suggests different implications of clinical chorioamnionitis in preterm and term pregnancy.Summary: Current diagnostic criteria of clinical chorioamnionitis should be revised, specifically in terms of sensitivity in preterm pregnancy and specificity in term pregnancy.

Chorioamnionitis exposure remodels the unique histone modification landscape of neonatal monocytes and alters the expression of immune pathway genes

Chorioamnionitis is an intrauterine infection involving inflammation of the chorion, amnion, and placenta. It leads to a fetal systemic inflammatory response that can alter the transcription of neonatal immune genes. We have previously shown that neonatal monocytes gain the activating histone tail modification H3K4me3 at promoter sites of immunologically important genes as development progresses from preterm neonate to adult. In this study, we applied ChIP-seq and RNA-seq to evaluate the impact of chorioamnionitis on the neonatal monocyte H3K4me3 histone modification landscape over the course of fetal and neonatal immune system development. Chorioamnionitis exposure in neonatal monocytes resulted in a net increase in total monocyte H3K4me3, primarily in introns and intergenic regions. Immune gene expression was decreased in chorioamnionitis-exposed monocytes, with the majority of enriched transcripts falling into pathways that are not linked to the immune system. Over half of all neonatal monocyte H3K4me3 peaks, independent of their location, were associated with active gene transcription. Overall, chorioamnionitis exposure resulted in the global remodeling of the neonatal monocyte H3K4me3 landscape and changes in the expression of known immune genes. These changes resulted in a less robust inflammatory response upon exposure to a secondary challenge, which may explain why chorioamnionitis-exposed neonates have an increased risk of sepsis. DATABASE: ChIP-seq data for U30/O30/Term: GEO GSE81957 ChIP-seq data for U30C/O30C/TermC: GEO GSE111873 RNA-seq data for U/L/CU/CL: GEO GSE111927.

Cytokine Changes in Maternal Peripheral Blood Correlate With Time-to-Delivery in Pregnancies Complicated by Premature Prelabor Rupture of the Membranes

Premature prelabor rupture of the membranes (PPROM) causes one-third of preterm births worldwide and is most likely caused by subclinical intrauterine infection and/or inflammation. We proposed that women with systemic inflammation at the time of PPROM would have shorter latency. Peripheral blood samples were collected from 20 singleton pregnant women with PPROM between 23 ± 1 and 33 ± 6 weeks. The first sample was drawn within 48 hours of admission, followed by weekly blood draws until delivery. Pregnancies complicated with acute chorioamnionitis, preeclampsia, intrauterine growth restriction, obesity, substance abuse, and chronic maternal disease were excluded. Twenty uncomplicated, gestational age-matched pregnancies served as controls. Plasma concentration of 39 cytokines was measured longitudinally using Luminex assays to investigate their value as predictive biomarkers of latency. Women with PPROM exhibited significantly lower plasma concentration of interferon-γ-inducible protein 10-Chemokine (c-x-c motif; IP10/CXCL10), Chemokine (c-x-c motif) Ligand 9 (MIG/CXCL9), Platelet-derived growth factor BB (PDGFbb), and cutaneous T cell-attracting chemokine, also known as CCL27/CCL27 than controls at admission but significantly elevated interleukin (IL)1RA, tumor necrosis factor α, monocyte chemotactic protein-1/CCL2 at delivery compared to admission. Women with PPROM who delivered within 7 days had significantly lower plasma concentration of anti-inflammatory cytokine IL1RA than those with latency periods >7 days. The IL1RA and endotoxin activity in conjunction with clinical parameters results in excellent prediction of latency to delivery (area under the receiver-operating characteristic curve = 0.91). We concluded that higher levels of anti-inflammatory cytokines in women with PPROM were associated with increased latency until delivery, likely due to counterbalancing of proinflammatory load. When used in conjunction with other predictive characteristics of time until delivery, cytokines may further assist clinical decision-making and optimize pregnancy outcomes in women with PPROM.

Antenatal IL-1-dependent inflammation persists postnatally and causes retinal and sub-retinal vasculopathy in progeny

Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1β participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1β associated with preterm birth (PTB) in retinal vasculopathy (independent of hyperoxia) is unknown. Using a murine model of PTB induced with IL-1β injection in utero, we studied consequent retinal and choroidal vascular development; in this process we evaluated the efficacy of IL-1R antagonists. Eyes of foetuses exposed only to IL-1β displayed high levels of pro-inflammatory genes, and a persistent postnatal infiltration of inflammatory cells. This prolonged inflammatory response was associated with: (1) a marked delay in retinal vessel growth; (2) long-lasting thinning of the choroid; and (3) long-term morphological and functional alterations of the retina. Antenatal administration of IL-1R antagonists - 101.10 (a modulator of IL-1R) more so than Kineret (competitive IL-1R antagonist) - prevented all deleterious effects of inflammation. This study unveils a key role for IL-1β, a major mediator of chorioamnionitis, in causing sustained ocular inflammation and perinatal vascular eye injury, and highlights the efficacy of antenatal 101.10 to suppress deleterious inflammation.

Mid-trimester preterm premature rupture of membranes (PPROM): etiology, diagnosis, classification, international recommendations of treatment options and outcome

Mid-trimester preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 28 weeks of gestation, complicates approximately 0.4%-0.7% of all pregnancies. This condition is associated with a very high neonatal mortality rate as well as an increased risk of long- and short-term severe neonatal morbidity. The causes of the mid-trimester PPROM are multifactorial. Altered membrane morphology including marked swelling and disruption of the collagen network which is seen with PPROM can be triggered by bacterial products or/and pro-inflammatory cytokines. Activation of matrix metalloproteinases (MMP) have been implicated in the mechanism of PPROM. The propagation of bacteria is an important contributing factor not only in PPROM, but also in adverse neonatal and maternal outcomes after PPROM. Inflammatory mediators likely play a causative role in both disruption of fetal membrane integrity and activation of uterine contraction. The "classic PPROM" with oligo/an-hydramnion is associated with a short latency period and worse neonatal outcome compared to similar gestational aged neonates delivered without antecedent PPROM. The "high PPROM" syndrome is defined as a defect of the chorio-amniotic membranes, which is not located over the internal cervical os. It may be associated with either a normal or reduced amount of amniotic fluid. It may explain why sensitive biochemical tests such as the Amniosure (PAMG-1) or IGFBP-1/alpha fetoprotein test can have a positive result without other signs of overt ROM such as fluid leakage with Valsalva. The membrane defect following fetoscopy also fulfils the criteria for "high PPROM" syndrome. In some cases, the rupture of only one membrane - either the chorionic or amniotic membrane, resulting in "pre-PPROM" could precede "classic PPROM" or "high PPROM". The diagnosis of PPROM is classically established by identification of nitrazine positive, fern positive watery leakage from the cervical canal observed during in specula investigation. Other more recent diagnostic tests include the vaginal swab assay for placental alpha macroglobulin-1 test or AFP and IGFBP1. In some rare cases amniocentesis and infusion of indigo carmine has been used to confirm the diagnosis of PPROM. The management of the PPROM requires balancing the potential neonatal benefits from prolongation of the pregnancy with the risk of intra-amniotic infection and its consequences for the mother and infant. Close monitoring for signs of chorioamnionitis (e.g. body temperature, CTG, CRP, leucocytes, IL-6, procalcitonine, amniotic fluid examinations) is necessary to minimize the risk of neonatal and maternal complications. In addition to delayed delivery, broad spectrum antibiotics of penicillin or cephalosporin group and/or macrolide and corticosteroids have been show to improve neonatal outcome [reducing risk of chorioamnionitis (average risk ratio (RR)=0.66), neonatal infections (RR=0.67) and abnormal ultrasound scan of neonatal brain (RR=0.67)]. The positive effect of continuous amnioinfusion through the subcutaneously implanted perinatal port system with amniotic fluid like hypo-osmotic solution in "classic PPROM" less than 28/0 weeks' gestation shows promise but must be proved in future prospective randomized studies. Systemic antibiotics administration in "pre-PPROM" without infection and hospitalization are also of questionable benefit and needs to be further evaluated in well-designed randomized prospective studies to evaluate if it is associated with any neonatal benefit as well as the relationship to possible adverse effect of antibiotics on to fetal development and neurological outcome.

Impact of gestational nicotine exposure on intrauterine and fetal infection in a rodent model

We investigated the interaction between prenatal nicotine exposure and intrauterine infection using established rat models. Beginning at gestation day (GD) 6, dams were continuously infused with either saline or 6 mg/kg/day nicotine (Nic). At GD 14, dams received either sterile broth or 10⁵ colony-forming units Mycoplasma pulmonis (MP), resulting in four treatment groups: control (4 dams, 33 fetal units); MP only (5 dams, 55 fetal units); Nic only (5 dams, 61 fetal units), and Nic + MP (7 dams, 82 fetal units). At GD 18, nicotine exposure significantly increased (P ≤ 0.02) the percentage of amniotic fluids and fetuses infected by MP but did not impact colonization rates of maternal sites. Nicotine exposure significantly reduced the numbers of MP in the placenta required for high microbial loads (≥10⁴ color-changing units) in the amniotic fluid (P < 0.01). Fetal inflammatory response lesions were most extensive in the Nic only and Nic + MP groups (P < 0.0001). Control and MP only placentas were interleukin (IL)10-dominant, consistent with an M2/Th2 environment. Placentas exposed to nicotine shifted to a neutral environment, with equivalent levels of interferon gamma (IFNG) and IL10. Both IL6 and tumor necrosis factor (TNF) levels in amniotic fluid were highly elevated when both nicotine and infection were present. Our study suggests that prenatal exposure to nicotine increases the risk for intrauterine infection, lowers the infectious dose required to breach the placental barrier and infect the amniotic fluid and fetus, and alters the pathology and inflammatory profile associated with maternal and fetal sites.

Spontaneous preterm birth: advances toward the discovery of genetic predisposition

Evidence from family and twin-based studies provide strong support for a significant contribution of maternal and fetal genetics to the timing of parturition and spontaneous preterm birth. However, there has been only modest success in the discovery of genes predisposing to preterm birth, despite increasing sophistication of genetic and genomic technology. In contrast, DNA variants associated with other traits/diseases have been identified. For example, there is overwhelming evidence that suggests that the nature and intensity of an inflammatory response in adults and children are under genetic control. Because inflammation is often invoked as an etiologic factor in spontaneous preterm birth, the question of whether spontaneous preterm birth has a genetic predisposition in the case of pathologic inflammation has been of long-standing interest to investigators. Here, we review various genetic approaches used for the discovery of preterm birth genetic variants in the context of inflammation-associated spontaneous preterm birth. Candidate gene studies have sought genetic variants that regulate inflammation in the mother and fetus; however, the promising findings have often not been replicated. Genome-wide association studies, an approach to the identification of chromosomal loci responsible for complex traits, have also not yielded compelling evidence for DNA variants predisposing to preterm birth. A recent genome-wide association study that included a large number of White women (>40,000) revealed that maternal loci contribute to preterm birth. Although none of these loci harbored genes directly related to innate immunity, the results were replicated. Another approach to identify DNA variants predisposing to preterm birth is whole exome sequencing, which examines the DNA sequence of protein-coding regions of the genome. A recent whole exome sequencing study identified rare mutations in genes encoding for proteins involved in the negative regulation (dampening) of the innate immune response (eg, CARD6, CARD8, NLRP10, NLRP12, NOD2, TLR10) and antimicrobial peptide/proteins (eg, DEFB1, MBL2). These findings support the concept that preterm labor, at least in part, has an inflammatory etiology, which can be induced by pathogens (ie, intraamniotic infection) or "danger signals" (alarmins) released during cellular stress or necrosis (ie, sterile intraamniotic inflammation). These findings support the notion that preterm birth has a polygenic basis that involves rare mutations or damaging variants in multiple genes involved in innate immunity and host defense mechanisms against microbes and their noxious products. An overlap among the whole exome sequencing-identified genes and other inflammatory conditions associated with preterm birth, such as periodontal disease and inflammatory bowel disease, was observed, which suggests a shared genetic substrate for these conditions. We propose that whole exome sequencing, as well as whole genome sequencing, is the most promising approach for the identification of functionally significant genetic variants responsible for spontaneous preterm birth, at least in the context of pathologic inflammation. The identification of genes that contribute to preterm birth by whole exome sequencing, or whole genome sequencing, promises to yield valuable population-specific biomarkers to identify the risk for spontaneous preterm birth and potential strategies to mitigate such a risk.

In vivo evidence of inflammasome activation during spontaneous labor at term

OBJECTIVE

Upon inflammasome activation, the adaptor protein of the inflammasome ASC (apoptosis-associated speck-like protein containing a CARD) forms intracellular specks, which can be released into the extracellular space. The objectives of this study were to investigate whether (1) extracellular ASC is present in the amniotic fluid of women who delivered at term; (2) amniotic fluid ASC concentrations are greater in women who underwent spontaneous labor at term than in those who delivered at term in the absence of labor; and (3) amniotic epithelial and mesenchymal cells can form intracellular ASC specks in vitro.

METHODS

This retrospective cross-sectional study included amniotic fluid samples from 41 women who delivered at term in the absence of labor (n = 24) or underwent spontaneous labor at term (n = 17). Amniotic epithelial and mesenchymal cells were also isolated from the chorioamniotic membranes obtained from a separate group of women who delivered at term (n = 3), in which ASC speck formation was assessed by confocal microscopy. Monocytes from healthy individuals were used as positive controls for ASC speck formation (n = 3).

RESULTS

(1) The adaptor protein of the inflammasome ASC is detectable in the amniotic fluid of women who delivered at term; (2) amniotic fluid ASC concentration was higher in women who underwent spontaneous labor at term than in those who delivered at term without labor; and (3) amniotic epithelial and mesenchymal cells are capable of forming ASC specks and/or filaments in vitro.

CONCLUSION

Amniotic fluid ASC concentrations are increased in women who undergo spontaneous labor at term. Amniotic epithelial and mesenchymal cells are capable of forming ASC specks, suggesting that these cells are a source of extracellular ASC in the amniotic fluid. These findings provide in vivo evidence that there is inflammasome activation in the amniotic cavity during the physiological process of labor at term.

Are amniotic fluid neutrophils in women with intraamniotic infection and/or inflammation of fetal or maternal origin?

BACKGROUND

Neutrophils are the most abundant white blood cells found in the amniotic cavity of women with intraamniotic infection and/or inflammation. The current belief is that these neutrophils are of fetal origin. However, abundant neutrophils have been found in the amniotic fluid of women with a severe acute maternal inflammatory response but without a severe fetal inflammatory response in the placenta, suggesting that these innate immune cells can also be of maternal origin or a mixture of both fetal and maternal neutrophils.

OBJECTIVE

We sought to investigate the origin of amniotic fluid neutrophils from women with intraamniotic infection and/or inflammation and to correlate these findings with acute histologic maternal and fetal inflammatory responses in the placenta.

STUDY DESIGN

Amniotic fluid was collected from 15 women with suspected intraamniotic infection and/or inflammation (positive microbiological cultures and/or interleukin-6 concentrations ≥2.6 ng/mL). Amniotic fluid neutrophils were purified by fluorescence-activated cell sorting, DNA was extracted, and DNA fingerprinting was performed. DNA fingerprinting was also performed in the umbilical cord and maternal blood DNA. Fluorescence in situ hybridization was assayed in women with male neonates. Blinded placental histopathological evaluations were conducted.

RESULTS

First, DNA fingerprinting revealed that 43% (6/14) of women who underwent a single amniocentesis had mostly fetal neutrophils in the amniotic fluid. Second, DNA fingerprinting showed that 36% (5/14) of the women who underwent a single amniocentesis had predominantly maternal neutrophils in the amniotic fluid. Third, DNA fingerprinting indicated that 21% (3/14) of the women who underwent a single amniocentesis had an evident mixture of fetal and maternal neutrophils in the amniotic fluid. Fourth, DNA fingerprinting revealed that a woman who underwent 2 amniocenteses (patient 15) had fetal neutrophils first, and as infection progressed, abundant maternal neutrophils invaded the amniotic cavity. Fifth, fluorescence in situ hybridization confirmed DNA fingerprinting results by showing that both fetal and maternal neutrophils were present in the amniotic fluid. Sixth, most of the women who had predominantly amniotic fluid neutrophils of fetal origin at the time of collection delivered extremely preterm neonates (71% [5/7]). Seventh, all of the women who had predominantly amniotic fluid neutrophils of maternal origin at the time of collection delivered term or late preterm neonates (100% [6/6]). Eighth, 2 of the women who had an evident mixture of fetal and maternal neutrophils in the amniotic fluid at the time of collection delivered extremely preterm neonates (67% [2/3]), and the third woman delivered a term neonate (33% [1/3]). Finally, most of the women included in this study presented acute maternal and fetal inflammatory responses in the placenta (87% [13/15]).

CONCLUSION

Amniotic fluid neutrophils can be either predominantly of fetal or maternal origin, or a mixture of both fetal and maternal origin, in women with intraamniotic infection and/or inflammation. The findings herein provide evidence that both fetal and maternal neutrophils can invade the amniotic cavity, suggesting that both the fetus and the mother participate in the host defense mechanisms against intraamniotic infection.

A Role for the Inflammasome in Spontaneous Preterm Labor With Acute Histologic Chorioamnionitis

Inflammasomes are cytosolic multiprotein complexes that orchestrate inflammation in response to pathogens and endogenous danger signals. Herein, we determined whether the chorioamniotic membranes from women in spontaneous preterm labor with acute histologic chorioamnionitis (1) express major inflammasome components; (2) express caspase (CASP)-1 and CASP-4 as well as their active forms; (3) exhibit apoptosis-associated speck-like protein containing a CARD (ASC)/CASP-1 complex formation; and (4) release the mature forms of interleukin (IL)-1β and IL-18. We utilized quantitative reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, immunoblotting, and immunohistochemistry to determine the messenger RNA (mRNA) and protein expression of major inflammasome components, nucleotide-binding oligomerization domain (NOD) proteins, and the pro- and mature/active forms of CASP-1, CASP-4, IL-1β, and IL-18. The ASC/CASP-1 complex formation was determined using an in situ proximity ligation assay. When comparing the chorioamniotic membranes from women in spontaneous preterm labor with acute histologic chorioamnionitis to those without this placental lesion, we found that (1) the mRNA of NLR family pyrin domain-containing protein ( NLRP) 1, NLRP3, NLR family CARD domain-containing protein 4 ( NLRC4), and NOD2 were higher; (2) the NLRP3 protein was increased; (3) the mRNA and active form (p10) of CASP-1 were greater; (4) the mRNA and active form of CASP-4 were increased; (5) the mRNA and mature form of IL-1β were higher; (6) the mature form of IL-18 was elevated; and (7) ASC/CASP-1 complex formation was increased. In conclusion, spontaneous preterm labor with acute histologic chorioamnionitis is characterized by an upregulation of NLRP3 and the active form of CASP-4, as well as increased ASC/CASP-1 complex formation, which may participate in the activation of CASP-1 and the maturation of IL-1β and IL-18 in the chorioamniotic membranes. These findings provide the first evidence that supports a role for the inflammasome in the pathological inflammation implicated in spontaneous preterm labor with acute histologic chorioamnionitis.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

PROBLEM

To characterize the amniotic fluid (AF) inflammatory-related protein (IRP) network in patients with a sonographic short cervix (SCx) and to determine its relation to early preterm delivery (ePTD).

METHOD OF STUDY

A retrospective cohort study included women with a SCx (≤25 mm; n=223) who had amniocentesis and were classified according to gestational age (GA) at diagnosis and delivery (ePTD <32 weeks of gestation).

RESULTS

(i) In women with a SCx ≤ 22 1/7 weeks, the concentration of most IRPs increased as the cervix shortened; those with ePTD had a higher rate of increase in MIP-1α, MCP-1, and IL-6 concentrations than those delivering later; and (ii) the concentration of most IRPs and the correlation between several IRP pairs were higher in the ePTD group than for those delivering later.

CONCLUSION

Women with a SCx at 16-22 1/7 weeks have a unique AF cytokine network that correlates with cervical length at diagnosis and GA at delivery. This network may aid in predicting ePTD.

Twenty-four percent of patients with clinical chorioamnionitis in preterm gestations have no evidence of either culture-proven intraamniotic infection or intraamniotic inflammation

BACKGROUND

Recent studies on clinical chorioamnionitis at term suggest that some patients with this diagnosis have neither intraamniotic infection nor intraamniotic inflammation. A false-positive diagnosis of clinical chorioamnionitis in preterm gestation may lead to unwarranted preterm delivery.

OBJECTIVE

We sought to determine the frequency of intraamniotic inflammation and microbiologically proven amniotic fluid infection in patients with preterm clinical chorioamnionitis.

STUDY DESIGN

Amniocentesis was performed in singleton pregnant women with preterm clinical chorioamnionitis (<36 weeks of gestation). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8 concentration. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture; intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration of >23 ng/mL. Nonparametric and survival techniques were used for analysis.

RESULTS

Among patients with preterm clinical chorioamnionitis, 24% (12/50) had neither microbiologic evidence of intraamniotic infection nor intraamniotic inflammation. Microbial invasion of the amniotic cavity was present in 34% (18/53) and intraamniotic inflammation in 76% (38/50) of patients. The most common microorganisms isolated from the amniotic cavity were the Ureaplasma species. Finally, patients without microbial invasion of the amniotic cavity or intraamniotic inflammation had significantly lower rates of adverse outcomes (including lower gestational age at delivery, a shorter amniocentesis-to-delivery interval, acute histologic chorioamnionitis, acute funisitis, and significant neonatal morbidity) than those with microbial invasion of the amniotic cavity and/or intraamniotic inflammation.

CONCLUSION

Among patients with preterm clinical chorioamnionitis, 24% had no evidence of either intraamniotic infection or intraamniotic inflammation, and 66% had negative amniotic fluid cultures, using standard microbiologic techniques. These observations call for a reexamination of the criteria used to diagnose preterm clinical chorioamnionitis.

Neutrophil extracellular traps in acute chorioamnionitis: A mechanism of host defense

PROBLEM

Neutrophil extracellular traps (NETs) were recently described as a mechanism for microbial killing in the amniotic cavity of women with intra-amniotic infection. Such a clinical condition can result in acute chorioamnionitis, a placental lesion characterized by the infiltration of maternal neutrophils in the chorioamniotic membranes. Herein, we investigated whether these infiltrating neutrophils form NETs in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis.

METHOD OF STUDY

Chorioamniotic membrane samples were collected from women who underwent spontaneous term or preterm labor with acute chorioamnionitis (n=10 each). Controls included chorioamniotic membrane samples from women who delivered at term or preterm with or without labor in the absence of acute chorioamnionitis (n=10 each). NETs were visualized and semiquantified in the chorioamniotic membranes by using antibodies against neutrophil elastase and histone H3 in combination with DAPI staining.

RESULTS

Neutrophil extracellular traps were abundant in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis. NETs were rarely found, or not visualized at all, in the chorioamniotic membranes from women who delivered at term or preterm with or without labor in the absence of acute chorioamnionitis.

CONCLUSION

Neutrophil extracellular traps are abundant in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis. These findings suggest that chorioamniotic neutrophils can form NETs as a mechanism of host defense against infection or danger signals.

A Role for the Inflammasome in Spontaneous Labor at Term with Acute Histologic Chorioamnionitis

Inflammasomes are cytosolic signaling platforms that regulate the activation of caspase (CASP)-1, which induces the maturation of interleukin (IL)-1β and IL-18. Herein, we determined whether the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis express major inflammasome components and whether these changes are associated with the activation of CASP-1 and CASP-4 and the release of mature IL-1β and IL-18. When comparing the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis to those without this placental lesion, we found that (1) the messenger RNA (mRNA) abundance of NLR family pyrin domain containing 3 ( NLRP3), NLR family CARD domain containing 4 ( NLRC4), absent in melanoma 2 ( AIM2), and nucleotide binding oligomerization domain 2 ( NOD2) was higher; (2) the NLRP3 and NLRC4 protein quantities were increased; (3) the mRNA and protein expressions of CASP-1 and its active forms were greater; (4) CASP-4 was increased at the mRNA level only; (5) the mRNA and protein expressions of IL-1β and its mature form were higher; and (6) a modest increase in the total protein concentration and abundance of the mature form of IL-18 was observed. In vitro incubation of the chorioamniotic membranes with the CASP-1 inhibitor, VX765, decreased the release of endotoxin-induced IL-1β and IL-18 (2-fold) but not IL-6 or tumor necrosis factor α. In conclusion, spontaneous labor at term with acute histologic chorioamnionitis is characterized by an upregulation of inflammasome components which, in turn, may participate in the activation of CASP-1 and lead to the release of mature IL-1β by the chorioamniotic membranes. These results support a role for the inflammasome in the mechanisms responsible for spontaneous labor at term with acute histologic chorioamnionitis.

Vaginal fluid interleukin-6 concentrations as a point-of-care test is of value in women with preterm prelabor rupture of membranes

BACKGROUND

Preterm prelabor rupture of membranes is frequently complicated/accompanied by infection and inflammation in the amniotic cavity. A point-of-care determination of amniotic fluid interleukin-6 has been shown to be a potentially clinically useful approach to assess inflammatory status of the amniotic cavity. Amniocentesis in preterm prelabor rupture of membranes is not broadly used in clinical practice, and therefore, a shift toward a noninvasive amniotic fluid sampling method is needed.

OBJECTIVE

The first aim of this study was to evaluate the association between the point-of-care vaginal and amniotic fluid interleukin-6 concentrations in fresh unprocessed samples obtained simultaneously. The second goal was to determine the diagnostic indices and predictive value of the point-of-care assessment of vaginal fluid interleukin-6 concentration in the identification of microbial invasion of the amniotic cavity, intraamniotic inflammation, and microbial-associated intraamniotic inflammation in patients with preterm prelabor rupture of membranes.

STUDY DESIGN

A prospective cohort study was conducted in women with singleton gestation complicated by preterm prelabor rupture of membranes at between 24+0 and 36+6 weeks. A total of 153 women with singleton pregnancies were included in this study. Vaginal fluid was obtained from the posterior vaginal fornix by aspiration with a sterile urine sample tube with a suction tip. Amniotic fluid was obtained by transabdominal amniocentesis. Interleukin-6 concentrations were assessed with a lateral flow immunoassay in both fluids immediately after sampling. Microbial invasion of the amniotic cavity was determined based on a positive polymerase chain reaction analysis. Intraamniotic inflammation was defined as an amniotic fluid point-of-care interleukin-6 concentration ≥745 pg/mL.

RESULTS

Several results were obtained in this study. First, it was possible to perform the point-of-care assessment of interleukin-6 in vaginal fluid in 92% of the women (141 of 153), and only those women were included in the analyses. Second, the rate of microbial invasion of the amniotic cavity and intraamniotic inflammation was 26% (36 of 141) and 19% (27 of 141), respectively. Microbial-associated intraamniotic inflammation was identified in 12% of the women (17 of 141). Third, a strong positive correlation was found between the interleukin-6 concentrations in vaginal and amniotic fluids (Spearman rho 0.68; P < .0001). Fourth, the presence of microbial invasion of the amniotic cavity, intraamniotic inflammation, or microbial-associated intraamniotic inflammation was associated with higher vaginal fluid interleukin-6 concentrations in both crude and adjusted analyses. Fifth, a vaginal fluid interleukin-6 concentration of 2500 pg/mL was determined to be the best cutoff value for the identification of microbial invasion of the amniotic cavity (sensitivity of 53% [19 of 36], specificity of 89% [93 of 104], positive predictive value of 63% [19 of 30], negative predictive value of 85% [93 of 110], positive likelihood ratio of 5.0 [95% confidence interval, 2.5-9.5], and negative likelihood ratio of 0.5 [95% confidence interval, 0.4-0.8]); intraamniotic inflammation (sensitivity of 74% [20/27], specificity of 91% [104/114], positive predictive value of 67% [20 of 30], negative predictive value of 94% [104 of 111], positive likelihood ratio of 8.4 [95% confidence interval, 4.5-15.9], and negative likelihood ratio of 0.3 [95% confidence interval, 0.2-0.5]); and microbial-associated intraamniotic inflammation (sensitivity of 100% [17 of 17], specificity of 90% [111 of 124), positive predictive value of 57% [17 of 30], negative predictive value of 100% [111 of 111], positive likelihood ratio of 9.5 [95% confidence interval, 5.7-16.0], and negative likelihood ratio of 0).

CONCLUSION

The point-of-care assessment of interleukin-6 in vaginal fluid is an easy, rapid, noninvasive, and inexpensive method for the identification of intraamniotic inflammation and microbial-associated intraamniotic inflammation in preterm prelabor rupture of membranes pregnancies, showing good specificity and negative predictive value.