Intra-amniotic Inflammation Research Articles

Periodontal disease and intra-amniotic complications in women with preterm prelabor rupture of membranes

Objective: Periodontal disease is frequently suggested as a possible causal factor for preterm delivery. The link between periodontal disease and preterm delivery is a possible translocation of periopathogenic bacteria to the placenta and amniotic fluid as well as a systemic response to this chronic inflammatory disease. However, there is a lack of information on whether there is an association between clinical periodontal status in women with preterm prelabor rupture of membranes (PPROM) and the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI). Therefore, the main aim of this study was to evaluate the incidence and severity of periodontal disease in women with PPROM. The secondary aim was to characterize an association between periodontal status and the presence of intra-amniotic PPROM complications (MIAC and/or IAI).Materials and methods: Seventy-eight women with PPROM at gestational ages between 24 + 0 and 36 + 6 weeks were included in this study. The samples of amniotic fluid were obtained at admission via transabdominal amniocentesis, and amniotic fluid interleukin (IL)-6 concentrations were determined using a point-of-care test. All women had a full-mouth recording to determine the periodontal and oral hygiene status. Probing pocket depth and clinical attachment loss were measured at four sites on each fully erupted tooth.Results: In total, 45% (35/78) of women with PPROM had periodontal disease. Mild, moderate, and severe periodontal disease was present in 19% (15/78), 19% (15/78), and 6% (5/78) of women, respectively. The presence of MIAC and IAI was found in 28% (22/78) and 26% (20/78) of women, respectively. Periopathogenic bacteria (2 × Streptococcus intermedius and 1 × Fusobacterium nucleatum) was found in the amniotic fluid of 4% (3/78) of women. There were no differences in periodontal status between women with MIAC and/or IAI and women without these intra-amniotic complications.Conclusions: The presence of MIAC and IAI was not related to the periodontal status of women with PPROM.

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity.

Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection. Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5). (i) Intra-amniotic infection-related bacteria including cocci (eg Streptococcus agalactiae), bacilli (eg Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (eg Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; (ii) peripheral neutrophils (controls) rapidly phagocytized S.agalactiae, U.urealyticum, Gardnerella vaginalis, and Escherichia coli; (iii) amniotic fluid neutrophils rapidly phagocytized S.agalactiae and G.vaginalis; and (iv) amniotic fluid neutrophils slowly phagocytized U.urealyticum and E.coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier. Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely S.agalactiae, U.urealyticum, G.vaginalis, and E.coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.

The combined exposure to intra-amniotic inflammation and neonatal respiratory distress syndrome increases the risk of intraventricular hemorrhage in preterm neonates.

To evaluate the impact of combined exposure to intra-amniotic inflammation and neonatal respiratory distress syndrome (RDS) on the development of intraventricular hemorrhage (IVH) in preterm neonates. This retrospective cohort study includes 207 consecutive preterm births (24.0-33.0 weeks of gestation). Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. According to McMenamin's classification, IVH was defined as grade II or higher when detected by neurosonography within the first weeks of life. (1) IVH was diagnosed in 6.8% (14/207) of neonates in the study population; (2) IVH was frequent among newborns exposed to intra-amniotic inflammation when followed by postnatal RDS [33% (6/18)]. The frequency of IVH was 7% (8/115) among neonates exposed to either of these conditions - intra-amniotic inflammation or RDS - and 0% (0/64) among those who were not exposed to these conditions; and (3) Neonates exposed to intra-amniotic inflammation and postnatal RDS had a significantly higher risk of IVH than those with only intra-amniotic inflammation [odds ratio (OR) 4.6, 95% confidence interval (CI) 1.1-19.3] and those with RDS alone (OR 5.6, 95% CI 1.0-30.9), after adjusting for gestational age. The combined exposure to intra-amniotic inflammation and postnatal RDS markedly increased the risk of IVH in preterm neonates.

Frequency and clinical significance of short cervix in patients with preterm premature rupture of membranes.

ObjectiveCervical length measurement has been uggested as a useful tool for predicting intra-amniotic infection/inflammation in preterm labor, but little information is available in the setting of preterm premature rupture of membranes (pPROM). We aimed to determine whether a short cervical length is independently associated with an increased risk of intra-amniotic infection or inflammation and impending preterm delivery in women with pPROM.MethodsThis was a retrospective cohort study involving 171 consecutive singleton pregnant women with pPROM (21+0–33+6 weeks’ gestation), who underwent amniocentesis. Amniotic fluid (AF) was cultured, and assayed for interleukin (IL)-6 and IL-8. Cervical length was measured at the time of amniocentesis by transvaginal ultrasonography with an aseptic technique. Short cervical length was defined as a cervical length of ≤15 mm. Intra-amniotic infection was defined as a positive AF culture for microorganisms and intra-amniotic inflammation was defined as elevated AF concentrations of IL-6 or IL-8 (IL-6 ≥1.5 ng/mL and/or IL-8 ≥1.3 ng/mL).ResultsFifty (29.2%) women had a sonographic cervical length of ≤15mm. On univariate analysis, short cervical length was associated with an increased risk for intra-amniotic infection and/or inflammation; no other parameters studied showed a significant association. Multivariable analyses indicated that short cervical length was significantly associated with a higher risk of impending preterm delivery (within 2 days of measurement, within 7 days of measurement, and before 34 weeks), and remained significant after adjustment for potential confounders.ConclusionIn women with pPROM, short cervical length is associated with an increased risk for intra-amniotic infection/inflammation and associated with impending preterm delivery, independent of the presence of intra-amniotic infection/inflammation.

Cervical fluid interleukin 6 and intra-amniotic complications of preterm prelabor rupture of membranes

Objective: To determine if cervical fluid interleukin (IL)-6 concentrations in women with preterm prelabor rupture of membranes (PPROM) allows identification of microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation (IAI).Methods: One hundred forty-four women with singleton pregnancies complicated by PPROM were included in this prospective cohort study. Cervical and amniotic fluids were collected at the time of admission and concentrations of IL-6 were measured using an ELISA and point-of-care test, respectively. Cervical fluid was obtained using a Dacron polyester swab and amniotic fluid was obtained by transabdominal amniocentesis. MIAC was diagnosed based on a positive PCR result for Ureaplasma species, M. hominis, and/or C. trachomatis and/or by positivity for the 16 S rRNA gene. IAI was defined as amniotic fluid point-of-care IL-6 concentrations ≥745 pg/mL. The women were assigned to four subgroups based on the presence of MIAC and/or IAI: microbial-associated IAI (both MIAC and IAI), sterile IAI (IAI alone), MIAC alone, and without either MIAC or IAI.Results: (1) Women with microbial-associated IAI had higher cervical fluid IL-6 concentrations (median 560 pg/mL) than did women with sterile IAI (median 303 pg/mL; p = .001), women with MIAC alone (median 135 pg/mL; p = .0004), and women without MIAC and IAI (median 180 pg/mL; p = .0001). (2) No differences were found in cervical fluid IL-6 concentrations among women with sterile IAI, with MIAC alone, and without MIAC and IAI. (3) A positive correlation was observed between cervical fluid IL-6 concentrations and the amount of Ureaplasma species in amniotic fluid (copies DNA/mL; rho = 0.57, p < .0001). (4) A weak positive correlation was detected between cervical and amniotic fluid IL-6 concentrations (rho = 0.33, p < .0001).Conclusions: The presence of microbial-associated IAI is associated with the highest cervical fluid IL-6 concentrations. Cervical IL-6 can be helpful in the identification of microbial-associated IAI.

A multicenter prospective study of neonatal outcomes at less than 32 weeks associated with indications for maternal admission and delivery

Counseling for patients with impending premature delivery traditionally has been based primarily on the projected gestational age at delivery. There are limited data regarding how the indications for the preterm birth affect the neonatal outcome and whether this issue should be taken into account in decisions regarding management and patient counseling. We performed a prospective study of pregnancies resulting in premature delivery at less than 32 weeks to determine the influence of both the indications for admission and their associated indications for delivery on neonatal mortality and complications of prematurity. This is a multicenter, prospective study in 10 hospitals where all data from the neonatal intensive care unit routinely was imported to a deidentified data warehouse. Maternal data were collected prospectively at or near the time of delivery. Eligible subjects included singleton deliveries in these hospitals between 23 0/7 and 31 6/7 weeks. The primary hypothesis of the study was to determine whether there was a difference in the primary outcome, which was defined as neonatal composite morbidity, between those neonates delivered after admission for premature labor vs premature rupture of membranes, because these were expected to be the 2 most frequent diagnoses leading to premature birth. The sample size was calculated based on a 10% difference in outcomes for these 2 entities. We based this hypothesis on the knowledge that premature rupture of membranes has a greater incidence of intra-amniotic infection and inflammation than premature labor and that outcomes for premature neonates are worse when delivery is associated with intra-amniotic infection. Additional outcomes were analyzed for all other indications for admission and delivery. Composite morbidity was defined as ≥1 of the following: respiratory distress syndrome (oxygen requirement, clinical diagnosis, and consistent chest radiograph), bronchopulmonary dysplasia (requirement for oxygen support at 28 days of life), severe intraventricular hemorrhage (grades 3 or 4), periventricular leukomalacia, blood culture-proven sepsis present within 72 hours of birth, necrotizing enterocolitis, or neonatal death before discharge from the hospital. A secondary composite of serious neonatal morbidity also was defined prospectively. The study included 1089 mother/baby pairs. Composite morbidity between those with premature labor (77.2%) and premature rupture of membranes (73.2%) was not significantly different (P= .29). A few neonatal complications were associated with indications for admission and delivery, but on logistic regression adjusting for gestational age and other confounders, suspected intrauterine growth restriction was the only indication for admission or delivery associated with an increase in serious morbidity (odds ratio 4.5, [2.1 to 9.8], P < .003). Other factors not related to the indications for admission including cesarean delivery, and low 5-minute Apgar were associated with an increase in morbidity. Studies of many single factors related to the indications for preterm delivery have been shown to be associated with adverse neonatal outcome. In this study evaluating all of the most frequent indications, however, we found only suspected intrauterine growth restriction as an indication for admission and delivery was found to be so. Thus, it seems that in almost all situations counseling patients can be based primarily on gestational age along with other factors including estimated fetal weight, sex, race, plurality, and completion of a course of antenatal corticosteroids.

Comparison of rapid MMP-8 and interleukin-6 point-of-care tests to identify intra-amniotic inflammation/infection and impending preterm delivery in patients with preterm labor and intact membranes

Objective: Among patients presenting with preterm labor and intact membranes, those with intra-amniotic inflammation have adverse obstetrical and neonatal outcomes. The diagnosis of intra-amniotic inflammation can easily be made by detecting an elevated concentration of the cytokine interleukin (IL)-6 or the enzyme neutrophil collagenase, also known as matrix metalloproteinase (MMP)-8. The diagnostic performances of MMP-8 and IL-6 enzyme-linked immunosorbent assay tests are similar. Recently, a rapid test has become available for point-of-care determination of either MMP-8 or IL-6. The objectives of this study were to compare the diagnostic indices and predictive values between the rapid MMP-8 and IL-6 tests for the identification of intra-amniotic inflammation in patients with preterm labor and intact membranes.Materials and methods: We performed a retrospective cohort study including 124 women with singleton pregnancies who presented with symptoms of preterm labor and underwent transabdominal amniocentesis for the evaluation of microbial invasion of the amniotic cavity (MIAC). MIAC was defined according to amniotic fluid culture results (aerobic and anaerobic bacteria as well as genital Mycoplasmas). Amniotic fluid white blood cell (WBC) counts were determined using a hemocytometer chamber. An elevated amniotic fluid MMP-8 concentration was assessed using Yoon’s MMP-8 Check® (cutoff: 10 ng/mL). An elevated amniotic fluid IL-6 concentration was scored when there was a positive result for the lateral flow-based immunoassay (cutoff: ≥745 pg/mL and ≥1000 pg/mL). In order to objectively compare rapid MMP-8 and rapid IL-6 tests to identify intra-amniotic inflammation, an amniotic fluid WBC count of ≥50 cells/mm3 was used to define intra-amniotic inflammation.Results: (1) The rapid tests had the same sensitivity for the detection of intra-amniotic inflammation [85.7% (18/21) for all]; (2) the specificity of the rapid MMP-8 test was higher than that of the rapid IL-6 test (cutoff: 745 pg/mL) for the identification of intra-amniotic inflammation [72.8% (75/103) vs. 64.1% (66/103); p < 0.05]; and (3) there were no differences in the sensitivity and specificity between the rapid MMP-8 test and the rapid IL-6 test (cutoff:1000 pg/mL) in the identification of intra-amniotic inflammation. Of 13 patients with discrepant results between the rapid MMP-8 and rapid IL-6 tests, two had a positive MMP-8 but a negative rapid IL-6 test, and both delivered preterm – one within 24 h, and the other within 10 days – and both had acute histologic chorioamnionitis. On the other hand, there were 11 patients with a positive rapid IL-6 but a negative rapid MMP-8 result: 10 delivered preterm, 3 had acute histologic chorioamnionitis and 1 had subacute chorionitis.Conclusion: We conclude that the rapid MMP-8 test has a better specificity than the rapid IL-6 (cutoff: 745 pg/mL) assay for the detection of intra-amniotic infection. Moreover, we observed that among patients who were not identified as having intra-amniotic infection or inflammation by the standard cultivation technique and amniotic fluid WBC count, those who had a positive MMP-8 rapid test delivered preterm and had acute histologic chorioamnionitis.

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

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

Cervical fluid calreticulin and cathepsin-G in pregnancies complicated by preterm prelabor rupture of membranes

Objective: The study aimed to determine the cervical calreticulin and cathepsin-G concentrations in pregnancies complicated by preterm prelabor rupture of membranes (PPROM) with respect to the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI).Methods: Eighty women with singleton pregnancies complicated by PPROM were included in this study. Cervical and amniotic fluids were obtained at the time of admission, and concentrations of calreticulin and cathepsin-G in cervical fluid were determined using ELISA. The MIAC was defined as a positive PCR analysis for Ureaplasma species, Mycoplasma hominis, and/or Chlamydia trachomatis and/or by positivity for the 16S rRNA gene. IAI was defined as amniotic fluid bedside IL-6 concentrations ≥745 pg/mLResult: Neither women with MIAC nor with IAI had different cervical fluid concentrations of calreticulin (with MIAC: median 18.9 pg/mL vs. without MIAC: median 14.7 pg/mL, p = 0.28; with IAI: median 14.3 pg/mL vs. without IAI: median 15.6 pg/mL, p = 0.57;) or of cathepsin-G (with MIAC: median 30.7 pg/mL vs. without MIAC: median 24.7 pg/mL, p = 0.28; with IAI: median 27.3 pg/mL vs. without IAI: median 25.1 pg/mL, p = 0.80) than women without those complications. No associations between amniotic fluid IL-6 concentrations, gestational age at sampling, and cervical fluid calreticulin and cathepsin-G concentrations were found.Conclusions: Cervical fluid calreticulin and cathepsin-G concentrations did not reflect the presence of MIAC or IAI in women with PPROM.

Transabdominal Amniocentesis Is a Feasible and Safe Procedure in Preterm Prelabor Rupture of Membranes

Objectives: To determine the feasibility and the complication rate of amniocentesis in a large cohort of women with preterm prelabor rupture of membranes (PPROM). Methods: A retrospective cohort study was conducted in all women with singleton gestation complicated by PPROM at between 24⁺⁰ and 36⁺⁶ weeks admitted to the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove, Czech Republic between May 2008 and July 2016. Amniocentesis was offered as a part of a routine protocol of PPROM for the detection of microbial invasion of the amniotic cavity and intra-amniotic inflammation. Procedure was performed under ultrasound guidance. A successful procedure was defined as obtaining at least 0.5 mL of amniotic fluid. No more than 2 attempts were performed. Results: In total, 590 women with PPROM were included. Amniocentesis was successful in 96% (567/590). Two amniocentesis attempts were necessary in 9% (55/590) and the transplacental approach was used in 13% (76/590). No association between gestational age at sampling and the amniocentesis failure rate was found (Spearman rho -0.12; p = 0.71). The complication rate was 0.7% (4/590). Two umbilical cord punctures and 2 chorionic plate fetal vessel injuries occurred, without fetal morbidity. Conclusion: Based on our study population, so far the largest published, amniocentesis is a feasible and safe procedure carrying a very low risk of failure or complications in PPROM.

Impact of microbial invasion of amniotic cavity and the type of microorganisms on short-term neonatal outcome in women with preterm labor and intact membranes.

The objective of this study was to evaluate the impact of microbial invasion of the amniotic cavity and the type of microorganisms on pregnancy and short-term neonatal outcomes in women with preterm labor. Prospective observational cohort study including women with preterm labor from 22.0 to 36.0 weeks. Microbial invasion of the amniotic cavity was defined based on amniotic fluid aerobic/anaerobic/mycoplasma cultures, and intra-amniotic inflammation on amniotic fluid interleukin-6 levels. Demographic data and pregnancy outcomes were compared among women exposed to microbial invasion of the amniotic cavity by Ureaplasma spp., women with microbial invasion of the amniotic cavity by other microorganisms, and a No-microbial invasion of the amniotic cavity/No-intra-amniotic inflammation group. The short-term neonatal outcome was evaluated in women delivering after 24.0 weeks. We included 228 women with preterm labor. Microbial invasion of the amniotic cavity occurred in 35% (80/228), 28% (22/80) being caused by Ureaplasma spp. Gestational age at admission and at delivery were significantly earlier and the rate of delivery at <24.0 weeks' gestation and of women who further developed clinical chorioamnionitis were significantly higher in women with microbial invasion of the amniotic cavity by microorganisms other than Ureaplasma spp. However, after 24 weeks, regardless of the microorganisms isolated, the short-term neonatal outcome was similar between women exposed to microbial invasion of the amniotic cavity and the No-microbial invasion of the amniotic cavity/No-intra-amniotic inflammation group when gestational age was considered. Microbial invasion of the amniotic cavity by microorganisms other than Ureaplasma spp. was associated with earlier gestational age at admission and at delivery, and a higher rate of preterm delivery <24.0 weeks and of women who developed clinical chorioamnionitis. However, we did not find differences in the short-term neonatal outcome between women exposed to microbial invasion of the amniotic cavity and the no-microbial invasion of the amniotic cavity/no-intra-amniotic inflammation group delivering after 24.0 weeks' gestation when adjusted by gestational age at delivery.

Does a prenatal bacterial microbiota exist?

Does a prenatal bacterial microbiota exist?

The Effects of Body Mass Index on Second-Trimester Amniotic Fluid Cytokine and Matrix Metalloproteinase Levels

Aim: The aim of this study was to determine the effects of obesity on amniotic fluid (AF) inflammatory markers in second-trimester AF, testing the hypothesis that there is a relationship between maternal body mass index (BMI) and fetal inflammatory exposure. Methods: AF was obtained from 84 singleton pregnant women undergoing elective amniocentesis for karyotype analysis at 16-24 weeks of gestation between April 2014 and May 2016. The cell-free AF was used to analyze interleukin (IL)-1β and IL-6, and matrix metalloproteinase (MMP)-1, MMP-6, and MMP-13. Results: IL-1β levels were significantly higher in class II-III obese patients than in class I obese, overweight, and normal weight patients (14.68 ± 1.37 vs. 13.34 ± 1.86 vs. 13.00 ± 2.22 vs. 10.78 ± 1.92, respectively; p < 0.05). IL-6 levels were lowest in the normal weight group and highest in class II-III obese patients. MMP-1, MMP-6, and MMP-13 levels were also significantly higher in class II-III obese patients than in the other groups. Conclusion: This study demonstrated that the fetuses of class II-III obese women are exposed in utero to higher cytokine and MMP levels than fetuses of lean women. Modification of current cutoff levels of intra-amniotic cytokines and MMPs according to the BMI could improve the accuracy of the prenatal diagnosis of intra-amniotic infection and inflammation.

332: Longer latency to delivery is associated with more frequent inflammation-free extra-placental membranes and umbilical cord in the setting of preterm-PROM with intra-amniotic inflammation

332: Longer latency to delivery is associated with more frequent inflammation-free extra-placental membranes and umbilical cord in the setting of preterm-PROM with intra-amniotic inflammation

115: Subclinical intra-amniotic inflammation in the midtrimester and the subsequent development of abnormal gross motor skills in infants born either term or preterm

115: Subclinical intra-amniotic inflammation in the midtrimester and the subsequent development of abnormal gross motor skills in infants born either term or preterm

305: Impact of microbial associated intra-amniotic inflammation and sterile inflammation on short-term neonatal outcome in women with preterm labor and intact membranes

305: Impact of microbial associated intra-amniotic inflammation and sterile inflammation on short-term neonatal outcome in women with preterm labor and intact membranes

446: Impact of sterile intra-amniotic inflammation on short term neonatal outcome in women with preterm prelabor rupture of membranes

446: Impact of sterile intra-amniotic inflammation on short term neonatal outcome in women with preterm prelabor rupture of membranes

464: The frequency and prognostic significance of intra-amniotic inflammation in preterm premature rupture of membranes before 25 weeks

464: The frequency and prognostic significance of intra-amniotic inflammation in preterm premature rupture of membranes before 25 weeks

Amniotic fluid clusterin in pregnancies complicated by the preterm prelabor rupture of membranes

Objective: The aim of this study was to evaluate clusterin concentrations in amniotic fluid in pregnancies complicated by preterm prelabor rupture of membranes (PPROM) with respect to the presence of the microbial invasion of the amniotic cavity (MIAC), intra-amniotic inflammation (IAI) and microbial-associated IAI.Methods: One hundred thirty-six women with singleton pregnancies complicated by PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid clusterin concentrations were assessed by enzyme-linked immunosorbent assay. MIAC was determined by a non-cultivation approach. IAI was defined as an amniotic fluid bedside interleukin-6 concentration ≥745 pg/mL. Microbial-associated IAI was characterized as the presence of both MIAC and IAI.Result: Women with MIAC, IAI and microbial-associated IAI had lower amniotic fluid clusterin concentrations than women without these complications (with MIAC: median 1314 ng/mL versus without MIAC: median 1633 ng/mL, p = 0.003; with IAI: median 1281 ng/mL versus without IAI: median 1575 ng/mL, p = 0.04; with microbial associated-IAI: median 1220 ng/mL versus without microbial-associated IAI: median 1575 pg/mL; p = 0.008). A week negative correlation between amniotic fluid clusterin concentrations and gestational age at sampling was revealed (rho= −0.30; p = 0.0005).Conclusions: The presence of MIAC, IAI and microbial-associated IAI was characterized by lower amniotic fluid clusterin concentrations in pregnancies complicated by PPROM.

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

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