Intra-amniotic Inflammation Research Articles

Antibiotic administration can eradicate intra-amniotic infection or intra-amniotic inflammation in a subset of patients with preterm labor and intact membranes

Intra-amniotic infection is present in 10% of patients with an episode of preterm labor, and is a risk factor for impending preterm delivery and neonatal morbidity/mortality. Intra-amniotic inflammation is often associated with intra-amniotic infection, but is sometimes present in the absence of detectable microorganisms. Antibiotic treatment of intra-amniotic infection has traditionally been considered to be ineffective. Intra-amniotic inflammation without microorganisms has a prognosis similar to that of intra-amniotic infection. To determine whether antibiotics can eradicate intra-amniotic infection or intra-amniotic inflammation in a subset of patients with preterm labor and intact membranes. The study population consisted of women who met the following criteria: 1) singleton gestation between 20 and 34 weeks; 2) preterm labor and intact membranes; 3) transabdominal amniocentesis performed for the evaluation of the microbiologic/inflammatory status of the amniotic cavity; 4) intra-amniotic infection and/or intra-amniotic inflammation; and 5) received antibiotic treatment that consisted of ceftriaxone, clarithromycin, and metronidazole. Follow-up amniocentesis was performed in a subset of patients. Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and polymerase chain reaction was performed for Ureaplasma spp. Intra-amniotic infection was defined as a positive amniotic fluid culture or positive polymerase chain reaction, and intra-amniotic inflammation was suspected when there was an elevated amniotic fluid white blood cell count or a positive result of a rapid test for matrix metalloproteinase-8. For this study, the final diagnosis of intra-amniotic inflammation was made by measuring the interleukin-6 concentration in stored amniotic fluid (>2.6 ng/mL). These results were not available to managing clinicians. Treatment success was defined as eradication of intra-amniotic infection and/or intra-amniotic inflammation or delivery ≥37 weeks. Of 62 patients with intra-amniotic infection and/or intra-amniotic inflammation, 50 received the antibiotic regimen. Of those patients, 29 were undelivered for ≥7 days and 19 underwent a follow-up amniocentesis. Microorganisms were identified by culture or polymerase chain reaction of amniotic fluid obtained at admission in 21% of patients (4/19) who had a follow-up amniocentesis, and were eradicated in 3 of the 4 patients. Resolution of intra-amniotic infection/inflammation was confirmed in 79% of patients (15/19), and 1 other patient delivered at term, although resolution of intra-amniotic inflammation could not be confirmed after a follow-up amniocentesis. Thus, resolution of intra-amniotic inflammation/infection or term delivery (treatment success) occurred in 84% of patients (16/19) who had a follow-up amniocentesis. Treatment success occurred in 32% of patients (16/50) with intra-amniotic infection/inflammation who received antibiotics. The median amniocentesis-to-delivery interval was significantly longer among women who received the combination of antibiotics than among those who did not (11.4 days vs 3.1 days: P= .04). Eradication of intra-amniotic infection/inflammation after treatment with antibiotics was confirmed in 79% of patients with preterm labor, intact membranes, and intra-amniotic infection/inflammation who had a follow-up amniocentesis. Treatment success occurred in 84% of patients who underwent a follow-up amniocentesis and in 32% of women who received the antibiotic regimen.

Prognostic value of intraamniotic interleukin-6 and cervical length in monochorionic twins after fetal surgery

Introduction: High concentration of intraamniotic interleukin-6 (IL-6) is associated with intraamniotic inflammation. Short cervical length is a risk predictor of premature rupture of membranes. Both parameters are associated with adverse perinatal outcomes. The aim of our study is to select patients at higher risk of severe prematurity after fetal surgery.

Amniocentesis prior to cerclage: An invasive strategy to exclude patients with sub-clinical intraamniotic inflammation before treatment

Introduction: Cervical cerclage is performed in patients with cervical insufficiency to reduce risks of misscariage/extreme prematurity. Severe complications can occur if performed in patients with intraamniotic inflammation. High levels of intraamniotic interleukin-6 (IL-6) are associated with histological chorioamnionitis. In expert hands amniocentesis is considered a safe procedure which we use routinely in management of PPROM. The aim of our study is to validate our strategy – diagnostic amniocentesis prior to cerclage.

A high concentration of fetal fibronectin in cervical secretions increases the risk of intra-amniotic infection and inflammation in patients with preterm labor and intact membranes

Objective To determine whether the risk of intra-amniotic infection/inflammation and spontaneous preterm delivery (SPTD) varies as a function of the concentration of cervical fetal fibronectin (fFN) in patients with preterm labor and intact membranes. Methods This prospective study included 180 patients with preterm labor and intact membranes who had a sample collected for quantitative fFN measurement and underwent amniocentesis. Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas. Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. Results (1) The prevalence of intra-amniotic infection/inflammation and SPTD within 7 days was 32.2% (58/180) and 33.9% (61/178), respectively; (2) The higher the fFN concentration, the greater the risk of intra-amniotic infection/inflammation and SPTD within 7 days (P<0.001, respectively); (3) An fFN concentration 150 ng/mL had a better diagnostic performance than an fFN 50 ng/mL in the identification of intra-amniotic infection/inflammation and SPTD within 7 days; (4) Among the patients with an fFN <50 ng/mL, intra-amniotic infection/inflammation was identified in 7.6% (6/79) of patients and 66.7% (4/6) delivered within 7 days. Conclusion The higher the concentration of fFN, the greater the risk of intra-amniotic infection/inflammation and SPTD in patients with preterm labor and intact membranes.

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

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

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.

542: Influence of vaginal microbiota on the pathophysiology of intra-amniotic infection and sterile-inflammation in preterm labor

Intra-amniotic infection and intra-amniotic inflammation (IAI) are leading responsible of spontaneous preterm delivery at early gestational ages being the ascending pathway the most common dissemination way. The influence of intra-amniotic infection and IAI on the vaginal diversity and Lactobacillus spp. abundance is poorly unknown. Our aim was to evaluate, in women with preterm labor (PTL), whether vaginal microbiota differs among different infectious/inflammatory phenotypes. Women admitted with PTL <34.0 weeks with an amniocentesis to rule out infection or IAI were included. Vaginal fluid was collected within 24 h after amniocentesis. Intra-amniotic infection was diagnosed based on amniotic fluid (AF) cultures or a positive AF PCR of 16S rDNA. IAI was defined based on AF IL-6 levels (≥13.4 ng/mL). Sequencing of 16S rRNA gene was performed using MiSeq platform. Data processing was performed using QIIME. Statistical analyses were performed using R and SPSS program (v24.0). Sixty-nine women were included being 26% women with intra-amniotic infection and 10% women with sterile IAI (negative culture but high levels of IL6). Only one woman with intra-amniotic infection had low levels of IL-6. Most common microorganisms isolated in the amniotic fluid were Ureaplasma spp. 37%. No differences were observed regarding progesterone administration or cerclage among groups. We found differences on ethnicity so sequencing data was adjusted for this variable. Higher diversity (Shannon index), (p = 0.02) and lower Lactobacillus spp. abundance (p = 0.01) were observed in women with intra-amniotic infection compared with the non-infection/non-IAI group. Using LEfSE test, we observed at genera level that Ureaplasma was enriched in women with infection, Haemophilus in women with sterile IAI and Lactobacillus in women with non-infection/non-IAI group. Vaginal diversity (OR = 2.8, CI 95% (1.1 – 7.1)) and Lactobacillus spp. abundance (OR = 0.98, CI 95% (0.97 – 0.99)) were found to be independent factors of preterm delivery < 34 weeks being Ureaplasma spp. an independent risk factor for preterm delivery < 32 weeks (OR = 1.7, CI 95% (1.0 – 2.7)). A higher vaginal diversity and lower Lactobacillus spp. abundance was observed in women with intra-amniotic infection being Lactobacillus spp. the microorganism dominated in women without infection or IAI.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

780: The progressive involvement of placenta in case of chorionamnionitis according to Triple I classification

The objective of the study was to verify the appearance of signs of suspected Triple I and the progressive involvement of placenta according to Redline classification of chorionamnionitis (CHA) and to understand the impact of CHA on maternal and neonatal outcome A retrospective cohort study of histological placental analysis obtained after term pregnancies between 2014-2017 at Carate Brianza Hospital, University of Milano-Bicocca. Included were all cases of HCA. The diagnosis of maternal fever (T°) and suspected intraamniotic inflammation, infection or both was made according to Triple I classification (IAI). Maternal adverse outcomes were defined as postpartum haemorrhage, endometritis or composite bad outcome (Mbad) including fever after hospital discharge and/or prolonged antibiotic therapy. Neonatal adverse outcomes were defined as asphyxia, positive blood culture, high CRP or composite bad outcome (Nbad) including admission to NICU and/or prolonged antibiotic therapy. Histological CHA was stadiated for severity according to Redline classification. Analyses were conducted by SPSS® 24.0; p-value <0.05 was considered significant Among 6,962 deliveries, 1,314 placentas of which 1,122 at term, were analysed, 32.4 % due to signs of IAI in labour . 339 of placentas had HCA and 133 (39.2%) of them had a whole inflammatory involvement (PLw). The presence of T° plus all 3 other clinical signs of IAI (all T°) was significantly related to stage 1 (p<0.01), stage 2 (p<0.05) of maternal inflammatory placental involvement (PLm) moreover to stage 1 (p<0.01), stage 2 (p<0.02), stage 3 (p<0.01) of fetal inflammatory placental involvement (PLf). PLw was significantly related to all T° (p<0.028). Signs of IAI plus HCA was related at univariate and multivariate analysis to Mbad (OR 7.12, p < 0.008). Endometritis (p < 0.03) and Mbad (p < 0.02) were related to PLw. High CRP (p < 0.001) and positive blood neonatal culture (p < 0.001) were related to PLf The progressive appearance of more clinical sign of IAI during labour at term is related to a gradual severe involvement of the placenta leading to HCA. Maternal and/or neonatal outcomes are more likely to be adverse when this diade is present: clinical signs of IAI and HCA.

Interleukin-6 measured using the automated electrochemiluminescence immunoassay method for the identification of intra-amniotic inflammation in preterm prelabor rupture of membranes

Introduction: We aimed to compare the amniotic fluid interleukin (IL)-6 concentrations measured using the automated electrochemiluminescence immunoassay method and ELISA, and to establish an IL-6 concentration cut-off value for intra-amniotic inflammation (IAI) in preterm prelabor rupture of membranes (PPROM), which can be used in the automated electrochemiluminescence immunoassay method.Materials and methods: A total of 120 women with PPROM were included in this study. Amniotic fluid samples were obtained through transabdominal amniocentesis. IL-6 concentrations were assessed using both the automated electrochemiluminescence immunoassay method and ELISA, the current gold standard. IAI was defined as an amniotic fluid IL-6 concentration of ≥2600 pg/mL measured using ELISA.Results: A correlation between both assays was found (Spearman’s rho = 0.97; p < .0001). Based on the receiver-operating characteristic curve for the identification of IAI (area under the curve = 0.99), a cut-off value of ≥3000 pg/mL was selected for the automated electrochemiluminescence immunoassay method with a sensitivity of 88%, specificity of 99%, positive predictive value of 97%, negative predictive value of 96%, and likelihood ratio of 76.Conclusions: For amniotic fluid IL-6 concentrations assessed using the automated electrochemiluminescence immunoassay method, a cut-off value of 3000 pg/mL was indicated for diagnosing IAI in women with PPROM.

Cervical human papillomavirus infection in women with preterm prelabor rupture of membranes.

ObjectiveTo evaluate the association between cervical human papillomavirus (HPV) infection at the time of admission and the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI) in women with preterm prelabor rupture of membranes (PPROM) and to determine the association between cervical HPV infection and short-term neonatal morbidity.MethodsOne hundred women with singleton pregnancies complicated by PPROM between the gestational ages of 24+0 and 36+6 weeks were included in the study. The presence of HPV DNA was evaluated in scraped cervical cells using polymerase chain reaction (PCR). Amniotic fluid samples were obtained by transabdominal amniocentesis.ResultsThe rate of cervical HPV infection in women with PPROM was 24%. The rates of MIAC and IAI were not different between women with cervical HPV infection and those without cervical HPV infection [MIAC: with HPV: 21% (5/24) vs. without HPV: 22% (17/76), p = 1.00; IAI: with HPV: 21% (5/24) vs. without HPV: 18% (14/76), p = 0.77]. There were no differences in the selected aspects of short-term neonatal morbidity between women with and without cervical HPV infection.ConclusionsIn women with PPROM, the presence of cervical HPV infection at the time of admission is not related to a higher risk of intra-amniotic infection-related and inflammatory complications or worse short-term neonatal outcomes.

Clinical chorioamnionitis at term IX: in vivo evidence of intra-amniotic inflammasome activation.

Background The inflammasome has been implicated in the mechanisms that lead to spontaneous labor at term. However, whether the inflammasome is activated in the amniotic cavity of women with clinical chorioamnionitis at term is unknown. Herein, by measuring extracellular ASC [apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (CARD)], we investigated whether there is in vivo inflammasome activation in amniotic fluid of patients with clinical chorioamnionitis at term with sterile intra-amniotic inflammation and in those with intra-amniotic infection. Methods This was a retrospective cross-sectional study that included amniotic fluid samples collected from 76 women who delivered after spontaneous term labor with diagnosed clinical chorioamnionitis. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin (IL)-6 concentration ≥2.6 ng/mL, and intra-amniotic infection was diagnosed by the presence of microbial invasion of the amniotic cavity (MIAC) accompanied by intra-amniotic inflammation. Patients were classified into the following groups: (1) women without intra-amniotic inflammation or infection (n=16); (2) women with MIAC but without intra-amniotic inflammation (n=5); (3) women with sterile intra-amniotic inflammation (n=15); and (4) women with intra-amniotic infection (n=40). As a readout of in vivo inflammasome activation, extracellular ASC was measured in amniotic fluid by enzyme-linked immunosorbent assay. Acute inflammatory responses in the amniotic fluid and placenta were also evaluated. Results In clinical chorioamnionitis at term: (1) amniotic fluid concentrations of ASC (extracellular ASC is indicative of in vivo inflammasome activation) and IL-6 were greater in women with intra-amniotic infection than in those without intra-amniotic inflammation, regardless of the presence of MIAC; (2) amniotic fluid concentrations of ASC and IL-6 were also higher in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation, regardless of the presence of MIAC; (3) amniotic fluid concentrations of IL-6, but not ASC, were more elevated in women with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (4) a positive and significant correlation was observed between amniotic fluid concentrations of ASC and IL-6; (5) no differences were observed in amniotic fluid ASC and IL-6 concentrations between women with and without MIAC in the absence of intra-amniotic inflammation; (6) women with intra-amniotic infection had elevated white blood cell counts and reduced glucose levels in amniotic fluid compared to the other three study groups; and (7) women with intra-amniotic infection presented higher frequencies of acute maternal and fetal inflammatory responses in the placenta than those with sterile intra-amniotic inflammation. Conclusion The intra-amniotic inflammatory response, either induced by alarmins or microbes, is characterized by the activation of the inflammasome - as evidenced by elevated amniotic fluid concentrations of extracellular ASC - in women with clinical chorioamnionitis at term. These findings provide insight into the intra-amniotic inflammatory response in women with clinical chorioamnionitis at term.

Amniotic fluid cell-free DNA in preterm prelabor rupture of membranes.

We evaluated the levels of cell-free nuclear DNA (nDNA) and cell-free mitochondrial DNA (mtDNA) in the amniotic fluid supernatant from pregnancies complicated by preterm prelabor rupture of membranes (PPROM) based on evidence of microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation (IAI). A total of 155 women with PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. The levels of cell-free nDNA and mtDNA in the amniotic fluid supernatant were assessed and quantified by real-time polymerase chain reaction. The levels of cell-free nDNA and mtDNA were higher in women with MIAC and IAI than in women without these conditions (nDNA: with MIAC: median 3.9×104 genome equivalent [GE]/mL vs without MIAC: median 1.2×104 GE/mL, with IAI: median: 5.3×104 GE/mL vs without IAI: median 1.2×104 GE/mL; mtDNA: with MIAC: median 9.2×105 GE/mL vs without MIAC: median 2.5×105 GE/mL, with IAI: median 1.1×106 GE/mL vs without IAI: median 2.5×105 ; all P values≤0.01). Women with the microbial-associated IAI showed the highest levels of cell-free nDNA and mtDNA. Cell-free nDNA and mtDNA are constituents of the amniotic fluid supernatant from PPROM pregnancies. Both cell-free nDNA and mtDNA are involved in the intra-amniotic inflammatory response in women with PPROM.

Cervical and Amniotic Fluid Matrix Metalloproteinase-8 and Interleukin-6 Concentrations in Preterm Pregnancies with or without Preterm Premature Rupture of Membranes

Introduction: Intra-amniotic inflammation is defined by elevated inflammatory biomarkers in the amniotic fluid (AF), either due to microbial invasion of the amniotic cavity (MIAC) or sterile inflammation. Amniocentesis being an invasive procedure, we wanted to investigate whether elevated matrix metalloproteinase-8 (MMP-8) or interleukin-6 (IL-6) concentrations could be detected from cervical fluid samples. Materials and Methods: This prospective study included 67 women with singleton nondiabetic pregnancies with or without preterm premature rupture of membranes (PPROM) between 22⁺⁰ and 37⁺⁰ weeks of gestation. Simultaneous AF and cervical samples were obtained. Results: In women without PPROM, cervical MMP-8 concentrations correlated with AF MMP-8 concentrations (r_S = 0.466, p = 0.002), but cervical IL-6 did not correlate with AF IL-6 (r_S = 0.277, p = 0.076). In PPROM cases no correlations were found. Women with MIAC had higher concentrations of AF MMP-8 and AF IL-6 compared to women without MIAC regardless of membrane status. However, only women without PPROM had higher concentrations of cervical MMP-8 in proven MIAC. Conclusion: In women without PPROM, cervical MMP-8 concentration reflects the magnitude of AF MMP-8, thus potentially guiding the selection of patients benefitting from amniocentesis.

Prenatal Intra-Amniotic Endotoxin Induces Fetal Gut and Lung Immune Responses and Postnatal Systemic Inflammation in Preterm Pigs

Prenatal inflammation is a major risk for preterm birth and neonatal morbidity, but its effects on postnatal immunity and organ functions remain unclear. Using preterm pigs as a model for preterm infants, we investigated whether prenatal intra-amniotic (IA) inflammation modulates postnatal systemic immune status and organ functions. Preterm pigs exposed to IA lipopolysaccharide (LPS) for 3days were compared with controls at birth and postnatal day 5 after formula feeding. IA LPS induced mild chorioamnionitis but extensive intra-amniotic inflammation. There were minor systemic effects at birth (increased blood neutrophil counts), but a few days later, prenatal LPS induced delayed neonatal arousal, systemic inflammation (increased blood leukocytes, plasma cytokines, and splenic bacterial counts), altered serum biochemistry (lower albumin and cholesterol and higher iron and glucose values), and increased urinary protein and sodium excretion. In the gut and lungs, IA LPS-induced inflammatory responses were observed mainly at birth (increased LPS, CXCL8, and IL-1β levels and myeloperoxidase-positive cell density, multiple increases in innate immune gene expressions, and reduced villus heights), but not on postnatal day 5 (except elevated lung CXCL8 and diarrhea symptoms). Finally, IA LPS did notaffect postnatal gut brush-border enzymes, hexose absorption, permeability, or sensitivity to necrotizing enterocolitis on day 5. Short-term IA LPS exposure predisposes preterm pigs to postnatal systemic inflammation after acute fetal gut and lung inflammatory responses.

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

The inflammasome is implicated in the mechanisms that lead to spontaneous preterm labor (PTL). However, whether there is inflammasome activation in the amniotic cavity of women with PTL and intra-amniotic infection (IAI) or sterile intra-amniotic inflammation (SIAI) is unknown. Amniotic fluid samples were collected from women with PTL who delivered at term (n=31) or preterm without IAI or SIAI (n=35), with SIAI (n=27), or with IAI (n=17). As a readout of inflammasome activation, extracellular ASC (apoptosis-associated speck-like protein containing a CARD) was measured in amniotic fluid by ELISA and the expression of ASC, caspase-1, and interleukin (IL)-1β was detected in the chorioamniotic membranes by multiplex immunofluorescence. Acute inflammatory responses in amniotic fluid and the placenta were also evaluated. (a) Amniotic fluid concentrations of ASC and IL-6 were higher in women with PTL and IAI or SIAI than in those who delivered preterm or at term without intra-amniotic inflammation; (b) amniotic fluid concentrations of ASC and IL-6 were lower in women with PTL and SIAI than in those with IAI; (c) there was a significant nonlinear correlation between ASC and IL-6 amniotic fluid concentrations; (d) the expression of inflammasome-related proteins (ASC, caspase-1, and IL-1β) in the chorioamniotic membranes was increased in women with PTL and IAI or SIAI than in those who delivered preterm or at term without intra-amniotic inflammation; (e) inflammasome activation in the chorioamniotic membranes was weaker in women with PTL and SIAI than in those with IAI; (f) women with PTL and IAI had elevated amniotic fluid white blood cell counts compared to those without this clinical condition; and (g) severe acute placental inflammatory lesions were observed in women with PTL and IAI and in a subset of women with PTL and SIAI. Inflammasome activation occurs in the settings of intra-amniotic infection and sterile intra-amniotic inflammation during spontaneous preterm labor.

The association between selected mid-trimester amniotic fluid candidate proteins and spontaneous preterm delivery

Objective: The aim of this study was to explore inflammatory response and identify early potential biomarkers in mid-trimester amniotic fluid associated with subsequent spontaneous preterm delivery (PTD).Methods: A cohort study was performed at Sahlgrenska University Hospital/Östra, Gothenburg, Sweden, between 2008 and 2010. Amniotic fluid was collected from consecutive women undergoing mid-trimester transabdominal genetic amniocentesis at 14–19 gestational weeks. Clinical data and delivery outcome variables were obtained from medical records. The analysis included 19 women with spontaneous PTD and 118 women who delivered at term. A panel of 26 candidate proteins was analyzed using Luminex xMAP technology. Candidate protein concentrations were analyzed with ANCOVA and adjusted for plate effects.Results: The median gestational age at delivery was 35 + 3 weeks in women with spontaneous PTD and 40 + 0 weeks in women who delivered at term. Nominally significantly lower amniotic fluid levels of adiponectin (PTD: median 130,695 pg/mL (IQR 71,852–199,414) vs term: median 185,329 pg/mL (IQR (135,815–290,532)), granulocyte-macrophage colony stimulating factor (PTD: median 137 pg/mL (IQR 74–156) vs term: median 176 pg/mL (IQR 111–262)), and macrophage migration inhibitory factor (PTD: median 3025 pg/mL (IQR 1885–3891) vs term: median 3400 pg/mL (IQR 2181–5231)) were observed in the spontaneous PTD group, compared with the term delivery group, after adjusting for plate effects. No significant differences remained after Bonferroni correction for multiple comparisons.Conclusions: Our results are important in the process of determining the etiology behind spontaneous PTD but due to the non-significance after Bonferroni correction, the results should be interpreted with caution. Further analyses of larger sample size will be required to determine whether these results are cogent and to examine whether microbial invasion of the amniotic cavity or intra-amniotic inflammation occurs in asymptomatic women in the mid-trimester with subsequent spontaneous PTD.

Human β-defensin-1: A natural antimicrobial peptide present in amniotic fluid that is increased in spontaneous preterm labor with intra-amniotic infection.

Human β-defensins (HBDs) are antimicrobial peptides that participate in the soluble innate immune mechanisms against infection. Herein, we determined whether HBD-1 was present in amniotic fluid during normal pregnancy and whether its concentrations change with intra-amniotic inflammation and/or infection. Amniotic fluid was collected from 219 women in the following groups: (a) midtrimester who delivered at term (n=35); (b) term with (n=33) or without (n=17) labor; (c) preterm labor with intact membranes who delivered at term (n=29) or who delivered preterm with (n=19) and without (n=29) intra-amniotic inflammation and infection or with intra-amniotic inflammation but without infection (n=21); and (d) preterm prelabor rupture of membranes (pPROM) with (n=19) and without (n=17) intra-amniotic inflammation/infection. Amniotic fluid HBD-1 concentrations were determined using a sensitive and specific ELISA kit. (a) HBD-1 was detectable in all amniotic fluid samples; (b) amniotic fluid concentrations of HBD-1 were changed with gestational age (midtrimester vs term no labor), being higher in midtrimester; (c) amniotic fluid concentrations of HBD-1 were similar between women with and without spontaneous labor at term; (d) among patients with spontaneous preterm labor, amniotic fluid concentrations of HBD-1 in women with intra-amniotic inflammation/infection and in those with intra-amniotic inflammation without infection were greater than in women without intra-amniotic inflammation or infection who delivered preterm or at term; and (e) the presence of intra-amniotic inflammation and infection in patients with pPROM did not change amniotic fluid concentrations of HBD-1. HBD-1 is a physiological constituent of amniotic fluid that is increased in midtrimester during normal pregnancy and in the presence of culturable microorganisms in the amniotic cavity. These findings provide insight into the soluble host defense mechanisms against intra-amniotic infection.

Intraamniotic inflammation and infection measured by invasive and non-invasive markers in women with threatening preterm delivery in relation to pregnancy outcome

Intraamniotic inflammation and infection measured by invasive and non-invasive markers in women with threatening preterm delivery in relation to pregnancy outcome

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

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

17OHP-C in patients with spontaneous preterm labor and intact membranes: is there an effect according to the presence of intra-amniotic inflammation?

It is not known whether 17-alpha-hydroxyprogesterone caproate (17OHP-C) is effective for preventing preterm delivery with an episode of preterm labor (PTL) with or without intra-amniotic inflammation/infection. This was a retrospective cohort study. One hundred and seven PTL patients were selected and divided into a 17OHP-C group (use of 17OHP-C: n=53) and a no-treatment group (no use of 17OHP-C: n=54). Moreover, the patients were divided into three subgroups (subgroup A: without intra-amniotic inflammation, B: with mild intra-amniotic inflammation, and C: with severe intra-amniotic inflammation) according to their level of amniotic interleukin (IL)-8, and perinatal prognosis was analyzed. Interval from admission to delivery (days) in the 17OHP-C group (76 [13-126], n=34) was significantly longer than that in the no-treatment group (50 [8-104], n=33; P=.012) in subgroup B. In cases without intra-amniotic microbes in subgroup B, a significant prolongation of gestational days was associated with the 17OHP-C group (79 [13-126], n=25) compared with the no-treatment group (50 [8-104], n=29; P=.029). However, there were no significant differences in subgroups A or C. 17OHP-C could prolong gestational period in limited PTL cases with sterile mild intra-amniotic inflammation.