Amniotic fluid matrix metalloproteinase-8 and the development of cerebral palsy

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

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

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Advances in cerebral palsy biomarkers

Cerebral palsy (CP), defined as a group of nonprogressive disorders of movement and posture, is the most common cause of severe neurodisability in children. The prevalence of CP is the same across the globe, affecting approximately 17 million people worldwide. Cerebral Palsy is an umbrella term used to describe the disease due to its inherent heterogeneity. For instance, CP has multiple (1) causes; (2) clinical types; (3) patterns of neuropathology on brain imaging and (4) it's associated with several developmental pathologies such as intellectual disability, autism, epilepsy, and visual impairment. Understanding its physiopathology is crucial to developing protective strategies. Despite its importance, there is still insufficient progress in the areas of CP prediction, early diagnosis, treatment, and prevention. Herein we describe the current risk factors and biomarkers used for the diagnosis and prediction of CP. With the advancement in biomarker discovery, we predict that our understanding of the etiopathophysiology of CP will also increase, lending to more opportunities for developing novel treatments and prognosis.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

(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.

CONCLUSION

The combined exposure to intra-amniotic inflammation and postnatal RDS markedly increased the risk of IVH in preterm neonates.

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. J Matern Fetal Neonatal Med 2018;31:228-244. [PMID: 28081646 PMCID: PMC5769687 DOI: 10.1080/14767058.2017.1281904]

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.

The diagnostic performance of the beta-glucan assay in the detection of intra-amniotic infection with Candida species

INTRODUCTION

A bioassay based on the detection of beta-glucan, a constituent of the cell wall of fungi, has been successfully used to diagnose fungal infections in a variety of biological fluids but not yet in the amniotic fluid.

OBJECTIVE

To determine the diagnostic performance of a beta-glucan bioassay in the detection of Candida species in the amniotic fluid of women who either did or did not have an intrauterine contraceptive device (IUD) in place during an episode of spontaneous preterm parturition.

METHODS

The study population comprised women who had a singleton pregnancy without congenital or chromosomal abnormalities, who experienced preterm labor or preterm prelabor rupture of the fetal membranes, and who underwent a transabdominal amniocentesis for clinical indications. Samples of amniotic fluid were cultured for aerobic and anaerobic bacteria, genital mycoplasmas, and Candida species, and assayed for beta-glucan, using the (1→3)-beta-d-glucan-specific Limulus amebocyte lysate test (beta-glucan assay) in all cases. Amniotic fluid interleukin (IL)-6 assay results were also available for all cases. The beta-glucan assay takes about 1 hour to run: a concentration >80 pg/mL was considered positive for fungi. Sterile intra-amniotic inflammation of the amniotic cavity was defined by the presence of an amniotic fluid IL-6 concentration ≥2.6 ng/mL and a negative amniotic fluid culture.

RESULTS

(1) One hundred ninety-seven (197) women met the study criteria, of whom 58 (29.4%) had an IUD in place; (2) 20 (10.2%) women had a culture of proven intra-amniotic Candida species-related infection, 19 of whom had a positive beta-glucan assay [sensitivity, 95% (19/20; 95% confidence interval (CI): 75.1-99.9%)]; and (3) the specificity of the beta-glucan assay was 75.1% [133/177; 95% CI: 68.1-99.9%]. It was affected by the presence of nonfungal intra-amniotic infections and an IUD, but not by the presence of sterile intra-amniotic inflammation, and there was a significant interaction between the presence of an IUD and nonfungal intra-amniotic infections (estimated for the interaction effect = 2.1923, p value =.026). The assay's specificity was reduced when nonfungal intra-amniotic infections were diagnosed but only in women who did not have an IUD. Among women without an IUD, the assay's specificity was 91.4% (117/128); it was 93% (106/114) for those without intra-amniotic infection, and 78.6% (11/14) for those with a nonfungal intra-amniotic infection; the difference was not significant (p = .09). Among women with an IUD, the assay's specificity was 32.7% (16/49); 42.9% (9/21) for those with a nonfungal intra-amniotic infection; and 25% (7/28) for those without intra-amniotic infection; and the difference was significant (p = .03).

CONCLUSIONS

The beta-glucan assay is a sensitive, rapid, point-of-care test used to diagnose intra-amniotic Candida species-related infection, and it has a high specificity in pregnant women who did not have an IUD in place.

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.

Clinical chorioamnionitis at term VIII: a rapid MMP-8 test for the identification of intra-amniotic inflammation

OBJECTIVE

Clinical chorioamnionitis is the most common infection/inflammatory process diagnosed in labor and delivery units worldwide. The condition is a syndrome that can be caused by (1) intra-amniotic infection, (2) intra-amniotic inflammation without demonstrable microorganisms (i.e. sterile intra-amniotic inflammation), and (3) maternal systemic inflammation that is not associated with intra-amniotic inflammation. The presence of intra-amniotic inflammation is a risk factor for adverse maternal and neonatal outcomes in a broad range of obstetrical syndromes that includes clinical chorioamnionitis at term. Although the diagnosis of intra-amniotic infection has relied on culture results, such information is not immediately available for patient management. Therefore, the diagnosis of intra-amniotic inflammation could be helpful as a proxy for intra-amniotic infection, while results of microbiologic studies are pending. A rapid test is now available for the diagnosis of intra-amniotic inflammation, based on the determination of neutrophil collagenase or matrix metalloproteinase-8 (MMP-8). The objectives of this study were (1) to evaluate the diagnostic indices of a rapid MMP-8 test for the identification of intra-amniotic inflammation/infection in patients with the diagnosis of clinical chorioamnionitis at term, and (2) to compare the diagnostic performance of a rapid MMP-8 test to that of a conventional enzyme-linked immunosorbent assay (ELISA) interleukin (IL)-6 test for patients with clinical chorioamnionitis at term.

MATERIALS AND METHODS

A retrospective cohort study was conducted. A transabdominal amniocentesis was performed in patients with clinical chorioamnionitis at term (n=44). Amniotic fluid was analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital Mycoplasmas) and broad-range polymerase chain reaction (PCR) coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). Amniotic fluid IL-6 concentrations were determined by ELISA, and rapid MMP-8 results were determined by Yoon's MMP-8 Check®. Intra-amniotic inflammation was defined as an elevated amniotic fluid IL-6 concentration ≥2.6 ng/mL, and intra-amniotic infection was diagnosed by the presence of microorganisms in the amniotic fluid accompanied by intra-amniotic inflammation. The diagnostic indices of Yoon's MMP-8 Check® for the identification of intra-amniotic inflammation were calculated. In order to objectively compare Yoon's MMP-8 Check® with the ELISA IL-6 test for the identification of intra-amniotic inflammation, we used an amniotic fluid white blood cell (WBC) count ≥50 cells/mm3 to define intra-amniotic inflammation.

RESULTS

(1) A positive rapid MMP-8 test had a sensitivity of 82.4% (28/34), specificity of 90% (9/10), positive predictive value of 96.6% (28/29), negative predictive value of 60% (9/15), positive likelihood ratio 8.2 (95% CI 1.3-53.2), and negative likelihood ratio 0.2 (95% CI 0.1-0.4) for the identification of intra-amniotic inflammation (prevalence 77.3%); (2) a positive rapid MMP-8 test had a sensitivity of 91.7% (22/24), specificity of 65% (13/20), positive predictive value of 75.9% (22/29), negative predictive value of 86.7% (13/15), positive likelihood ratio of 2.6 (95% CI 1.4-4.8), and negative likelihood ratio of 0.1 (95% CI 0.03-0.5) for the identification of intra-amniotic infection; (3) the rapid MMP-8 test had a significantly higher specificity than the ELISA IL-6 test in the identification of intra-amniotic inflammation as determined by an amniotic fluid WBC count ≥50 cells/mm3. The sensitivity and accuracy of the rapid MMP-8 test were comparable to those of the ELISA IL-6 test; and (4) importantly, the rapid MMP-8 test had 100% sensitivity and 100% negative predictive value in the identification of neonates affected with fetal inflammatory response syndrome (FIRS).

CONCLUSION

The rapid diagnosis of intra-amniotic inflammation is possible by analysis of amniotic fluid using a point-of-care test for MMP-8. Patients with a positive test are at risk of delivering a neonate affected with systemic inflammation, a risk factor for adverse neonatal outcome.

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.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

Clinical chorioamnionitis at term V: umbilical cord plasma cytokine profile in the context of a systemic maternal inflammatory response

OBJECTIVE

Microbial invasion of the fetus due to intra-amniotic infection can lead to a systemic inflammatory response characterized by elevated concentrations of cytokines in the umbilical cord plasma/serum. Clinical chorioamnionitis represents the maternal syndrome often associated with intra-amniotic infection, although other causes of this syndrome have been recently described. The objective of this study was to characterize the umbilical cord plasma cytokine profile in neonates born to mothers with clinical chorioamnionitis at term, according to the presence or absence of bacteria and/or intra-amniotic inflammation.

MATERIALS AND METHODS

A cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=38; cases) and those with spontaneous term labor without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) and amniotic fluid interleukin (IL)-6 concentration into three groups: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. A fetal inflammatory response syndrome (FIRS) was defined as an umbilical cord plasma IL-6 concentration >11 pg/mL. The umbilical cord plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) Neonates born to mothers with clinical chorioamnionitis at term (considered in toto) had significantly higher median umbilical cord plasma concentrations of IL-6, IL-12p70, IL-16, IL-13, IL-4, IL-10 and IL-8, but significantly lower interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF)-α concentrations than neonates born to mothers with spontaneous term labor without clinical chorioamnionitis; 2) neonates born to mothers with clinical chorioamnionitis at term but without intra-amniotic inflammation had higher concentrations of IL-6, IL-12p70, IL-13, IL-4, IL-5, and IL-8, but lower IFN-γ, than neonates not exposed to clinical chorioamnionitis, suggesting that maternal fever in the absence of intra-amniotic inflammation leads to a change in the fetal cytokine network; 3) there were significant, positive correlations between maternal and umbilical cord plasma IL-6 and IL-8 concentrations (IL-6: Spearman correlation=0.53; P<0.001; IL-8: Spearman correlation=0.42; P<0.001), consistent with placental transfer of cytokines; 4) an elevated fetal plasma IL-6 (>11 pg/mL), the diagnostic criterion for FIRS, was present in 21% of cases (8/38), and all these neonates were born to mothers with proven intra-amniotic infection; and 5) FIRS was associated with a high concentration of umbilical cord plasma IL-8, IL-10 and monocyte chemoattractant protein (MCP)-1.

CONCLUSIONS

Neonates born to mothers with clinical chorioamnionitis at term had higher concentrations of umbilical cord plasma cytokines than those born to mothers without clinical chorioamnionitis. Even neonates exposed to clinical chorioamnionitis but not to intra-amniotic inflammation had elevated concentrations of multiple cytokines, suggesting that intrapartum fever alters the fetal immune response.

About one-half of early spontaneous preterm deliveries can be identified by a rapid matrix metalloproteinase-8 (MMP-8) bedside test at the time of mid-trimester genetic amniocentesis

OBJECTIVE

Mid-trimester amniocentesis continues to be used for the prenatal diagnosis of chromosomal anomalies and other genetic disorders. Analysis of amniotic fluid obtained at the time of mid-trimester genetic amniocentesis identifies those patients who are at risk for early spontaneous preterm delivery. This is based on a solid body of evidence that found subclinical intra-amniotic inflammation/infection to be causally linked to early spontaneous preterm birth. Although several biomarkers have been proposed to identify intra-amniotic inflammation, the accumulated data suggest that the determination of amniotic fluid matrix metalloproteinase-8 (MMP-8), or neutrophil collagenase, is a powerful predictor of spontaneous preterm delivery. MMP-8 is released by inflammatory cells in response to microbial products or "danger signals". A rapid point-of-care test has been developed to determine MMP-8 at the bedside within 20 min, and without the requirement of laboratory equipment. The objective of this study was to determine whether an elevation of MMP-8 in the amniotic fluid, measured by a rapid point-of-care test, can identify those patients at risk for spontaneous preterm delivery after a mid-trimester genetic amniocentesis.

STUDY DESIGN

A case-control study was designed to obtain amniotic fluid from asymptomatic singleton pregnant women who underwent mid-trimester genetic amniocentesis. An MMP-8 bedside test was performed to analyze the amniotic fluid of 64 patients with early spontaneous preterm delivery (<30 weeks) and 128 matched controls with normal pregnancy outcomes.

RESULTS

(1) The MMP-8 bedside test (Yoon's MMP-8 Check™) was positive in 42.2% (27/64) of patients with spontaneous preterm delivery but in none (0/128) of the control cases (p < 0.001); (2) the MMP-8 bedside test had a sensitivity of 42.2%, and a specificity of 100% in the prediction of spontaneous preterm delivery (<30 weeks) following a mid-trimester genetic amniocentesis; and (3) among the patients with spontaneous preterm delivery, those with a positive MMP-8 bedside test had a significantly higher rate of spontaneous delivery within 2 weeks and 4 weeks of an amniocentesis [40.7% (11/27) versus 5.4% (2/37); 63.0% (17/27) versus 24.3% (9/37)] and a shorter interval-to-delivery period than those with a negative test [interval-to-delivery: median (range), 16 d (0-95 d) versus 42 d (2-91 d); p < 0.05 for each].

CONCLUSION

We conclude that 42% of patients with an early spontaneous preterm delivery (< 30 weeks) could be identified by a rapid MMP-8 bedside test at the time of their mid-trimester genetic amniocentesis. The MMP-8 bedside test is a powerful predictor of early spontaneous preterm birth in asymptomatic pregnant women.

A new antibiotic regimen treats and prevents intra-amniotic inflammation/infection in patients with preterm PROM

OBJECTIVES

To determine whether a new antibiotic regimen could reduce the frequency of intra-amniotic inflammation/infection in patients with preterm PROM.

STUDY DESIGN

This retrospective cohort study was conducted to evaluate the effect of antibiotics on the frequency of intra-amniotic inflammation/infection based on the results of follow-up transabdominal amniocenteses from 89 patients diagnosed with preterm PROM who underwent serial amniocenteses. From 1993-2003, ampicillin and/or cephalosporins or a combination was used ("regimen 1"). A new regimen (ceftriaxone, clarithromycin and metronidazole) was used from 2003-2012 ("regimen 2"). Amniotic fluid was cultured and matrix metalloproteinase-8 (MMP-8) concentrations were measured.

RESULTS

(1) The rates of intra-amniotic inflammation and intra-amniotic inflammation/infection in patients who received regimen 2 decreased during treatment from 68.8% to 52.1% and from 75% to 54.2%, respectively. In contrast, in patients who received regimen 1, the frequency of intra-amniotic inflammation and infection/inflammation increased during treatment (31.7% to 55% and 34.1% to 58.5%, respectively); and (2) intra-amniotic inflammation/infection was eradicated in 33.3% of patients who received regimen 2, but in none who received regimen 1.

CONCLUSION

The administration of ceftriaxone, clarithromycin and metronidazole was associated with a more successful eradication of intra-amniotic inflammation/infection and prevented secondary intra-amniotic inflammation/infection more frequently than an antibiotic regimen which included ampicillin and/or cephalosporins in patients with preterm PROM.

Evidence of perturbations of the cytokine network in preterm labor

OBJECTIVE

Intraamniotic inflammation/infection is the only mechanism of disease with persuasive evidence of causality for spontaneous preterm labor/delivery. Previous studies about the behavior of cytokines in preterm labor have been largely based on the analysis of the behavior of each protein independently. Emerging evidence indicates that the study of biologic networks can provide insight into the pathobiology of disease and improve biomarker discovery. The goal of this study was to characterize the inflammatory-related protein network in the amniotic fluid of patients with preterm labor.

STUDY DESIGN

A retrospective cohort study was conducted that included women with singleton pregnancies who had spontaneous preterm labor and intact membranes (n = 135). These patients were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry, and amniotic fluid concentration of interleukin (IL)-6 into the following groups: (1) those without intraamniotic inflammation (n = 85), (2) those with microbial-associated intraamniotic inflammation (n = 15), and (3) those with intraamniotic inflammation without detectable bacteria (n = 35). Amniotic fluid concentrations of 33 inflammatory-related proteins were determined with the use of a multiplex bead array assay.

RESULTS

Patients with preterm labor and intact membranes who had microbial-associated intraamniotic inflammation had a higher amniotic fluid inflammatory-related protein concentration correlation than those without intraamniotic inflammation (113 perturbed correlations). IL-1β, IL-6, macrophage inflammatory protein (MIP)-1α, and IL-1α were the most connected nodes (highest degree) in this differential correlation network (degrees of 20, 16, 12, and 12, respectively). Patients with sterile intraamniotic inflammation had correlation patterns of inflammatory-related proteins, both increased and decreased, when compared to those without intraamniotic inflammation (50 perturbed correlations). IL-1α, MIP-1α, and IL-1β were the most connected nodes in this differential correlation network (degrees of 12, 10, and 7, respectively). There were more coordinated inflammatory-related protein concentrations in the amniotic fluid of women with microbial-associated intraamniotic inflammation than in those with sterile intraamniotic inflammation (60 perturbed correlations), with IL-4 and IL-33 having the largest number of perturbed correlations (degrees of 15 and 13, respectively).

CONCLUSIONS

We report for the first time an analysis of the inflammatory-related protein network in spontaneous preterm labor. Patients with preterm labor and microbial-associated intraamniotic inflammation had more coordinated amniotic fluid inflammatory-related proteins than either those with sterile intraamniotic inflammation or those without intraamniotic inflammation. The correlations were also stronger in patients with sterile intraamniotic inflammation than in those without intraamniotic inflammation. The findings herein could be of value in the development of biomarkers of preterm labor.

Acute chorioamnionitis and funisitis: definition, pathologic features, and clinical significance

Acute inflammatory lesions of the placenta consist of diffuse infiltration of neutrophils at different sites in the organ. These lesions include acute chorioamnionitis, funisitis, and chorionic vasculitis and represent a host response (maternal or fetal) to a chemotactic gradient in the amniotic cavity. While acute chorioamnionitis is evidence of a maternal host response, funisitis and chorionic vasculitis represent fetal inflammatory responses. Intraamniotic infection generally has been considered to be the cause of acute chorioamnionitis and funisitis; however, recent evidence indicates that "sterile" intraamniotic inflammation, which occurs in the absence of demonstrable microorganisms induced by "danger signals," is frequently associated with these lesions. In the context of intraamniotic infection, chemokines (such as interleukin-8 and granulocyte chemotactic protein) establish a gradient that favors the migration of neutrophils from the maternal or fetal circulation into the chorioamniotic membranes or umbilical cord, respectively. Danger signals that are released during the course of cellular stress or cell death can also induce the release of neutrophil chemokines. The prevalence of chorioamnionitis is a function of gestational age at birth, and present in 3-5% of term placentas and in 94% of placentas delivered at 21-24 weeks of gestation. The frequency is higher in patients with spontaneous labor, preterm labor, clinical chorioamnionitis (preterm or term), or ruptured membranes. Funisitis and chorionic vasculitis are the hallmarks of the fetal inflammatory response syndrome, a condition characterized by an elevation in the fetal plasma concentration of interleukin-6, and associated with the impending onset of preterm labor, a higher rate of neonatal morbidity (after adjustment for gestational age), and multiorgan fetal involvement. This syndrome is the counterpart of the systemic inflammatory response syndrome in adults: a risk factor for short- and long-term complications (ie, sterile inflammation in fetuses, neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, and cerebral palsy). This article reviews the definition, pathogenesis, grading and staging, and clinical significance of the most common lesions in placental disease. Illustrations of the lesions and diagrams of the mechanisms of disease are provided.

A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM

OBJECTIVE

Antibiotic administration is a standard practice in preterm premature rupture of membranes (PROM). Specific anti-microbial agents often include ampicillin and/or erythromycin. Anaerobes and genital mycoplasmas are frequently involved in preterm PROM, but are not adequately covered by antibiotics routinely used in clinical practice. Our objective was to compare outcomes of PROM treated with standard antibiotic administration versus a new combination more effective against these bacteria.

STUDY DESIGN

A retrospective study compared perinatal outcomes in 314 patients with PROM <34 weeks receiving anti-microbial regimen 1 (ampicillin and/or cephalosporins; n = 195, 1993-2003) versus regimen 2 (ceftriaxone, clarithromycin and metronidazole; n = 119, 2003-2012). Intra-amniotic infection/inflammation was assessed by positive amniotic fluid culture and/or an elevated amniotic fluid MMP-8 concentration (>23 ng/mL).

RESULTS

(1) Patients treated with regimen 2 had a longer median antibiotic-to-delivery interval than those with regimen 1 [median (interquartile range) 23 d (10-51 d) versus 12 d (5-52 d), p < 0.01]; (2) patients who received regimen 2 had lower rates of acute histologic chorioamnionitis (50.5% versus 66.7%, p < 0.05) and funisitis (13.9% versus 42.9%, p < 0.001) than those who had received regimen 1; (3) the rates of intra-ventricular hemorrhage (IVH) and cerebral palsy (CP) were significantly lower in patients allocated to regimen 2 than regimen 1 (IVH: 2.1% versus 19.0%, p < 0.001 and CP: 0% versus 5.7%, p < 0.05); and (4) subgroup analysis showed that regimen 2 improved perinatal outcomes in pregnancies with intra-amniotic infection/inflammation, but not in those without intra-amniotic infection/inflammation (after adjusting for gestational age and antenatal corticosteroid administration).

CONCLUSION

A new antibiotic combination consisting of ceftriaxone, clarithromycin, and metronidazole prolonged the latency period, reduced acute histologic chorioamnionitis/funisitis, and improved neonatal outcomes in patients with preterm PROM. These findings suggest that the combination of anti-microbial agents (ceftriaxone, clarithromycin, and metronidazole) may improve perinatal outcome in preterm PROM.

Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes

OBJECTIVE

The objectives of this study were to: (1) determine the amniotic fluid (AF) microbiology of patients with preterm prelabor rupture of membranes (PROM); and (2) examine the relationship between intra-amniotic inflammation with and without microorganisms (sterile inflammation) and adverse pregnancy outcomes in patients with preterm PROM.

METHODS

AF samples obtained from 59 women with preterm PROM were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital mycoplasmas) and with broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). AF concentration of interleukin-6 (IL-6) was determined using ELISA. Results of both tests were correlated with AF IL-6 concentrations and the occurrence of adverse obstetrical/perinatal outcomes.

RESULTS

(1) PCR/ESI-MS, AF culture, and the combination of these two tests each identified microorganisms in 36% (21/59), 24% (14/59) and 41% (24/59) of women with preterm PROM, respectively; (2) the most frequent microorganisms found in the amniotic cavity were Sneathia species and Ureaplasma urealyticum; (3) the frequency of microbial-associated and sterile intra-amniotic inflammation was overall similar [ 29% (17/59)]: however, the prevalence of each differed according to the gestational age when PROM occurred; (4) the earlier the gestational age at preterm PROM, the higher the frequency of both microbial-associated and sterile intra-amniotic inflammation; (5) the intensity of the intra-amniotic inflammatory response against microorganisms is stronger when preterm PROM occurs early in pregnancy; and (6) the frequency of acute placental inflammation (histologic chorioamnionitis and/or funisitis) was significantly higher in patients with microbial-associated intra-amniotic inflammation than in those without intra-amniotic inflammation [93.3% (14/15) versus 38% (6/16); p = 0.001].

CONCLUSIONS

(1) The frequency of microorganisms in preterm PROM is 40% using both cultivation techniques and PCR/ESI-MS; (2) PCR/ESI-MS identified microorganisms in the AF of 50% more women with preterm PROM than AF culture; and (3) sterile intra-amniotic inflammation was present in 29% of these patients, and it was as or more common than microbial-associated intra-amniotic inflammation among those presenting after, but not before, 24 weeks of gestation.

The relationship between the intensity of intra-amniotic inflammation and the presence and severity of acute histologic chorioamnionitis in preterm gestation

OBJECTIVE

Acute histologic chorioamnionitis (HCA) is associated with an increased risk of perinatal mortality and morbidity. The purpose of this study was to determine the relationship between the intensity of intra-amniotic inflammation (IAI) and the severity of acute HCA in preterm gestation.

METHODS

The relationship between the intensity of IAI and the presence and severity of acute HCA was examined in 412 patients with singleton gestations who delivered within 120 h of transabdominal amniocentesis. The concentration of amniotic fluid (AF) matrix metalloproteinase (MMP)-8 was assayed to determine the presence and intensity of IAI. Acute HCA was defined as the presence of inflammatory change in any tissue samples according to the criteria previously reported. The total grade of acute HCA was used to determine the severity of HCA.

RESULTS

(1) Patients with IAI had a significantly higher rate of acute HCA than those without IAI [76.9% (133/173)] versus 20.9% (50/239), p < 0.001]. The AF MMP-8 concentration was significantly higher in patients with acute HCA than in those without acute HCA (median [range]; 188.3 ng/ml [0.3-6142.6] versus 1.8 ng/ml [0.3-2845.5], p < 0.001); (2) Of 183 patients with acute HCA, the AF MMP-8 concentration was positively correlated with the severity of acute HCA (p < 0.001).

CONCLUSIONS

AF MMP-8 concentration was not only a predictor of the presence of acute HCA, but its concentration also correlated with the severity of acute HCA. The higher the intensity of IAI, the worse the degree of acute HCA in preterm gestation.

The diagnostic performance of the Mass Restricted (MR) score in the identification of microbial invasion of the amniotic cavity or intra-amniotic inflammation is not superior to amniotic fluid interleukin-6

OBJECTIVE

Intra-amniotic infection/inflammation are major causes of spontaneous preterm labor and delivery. However, diagnosis of intra-amniotic infection is challenging because most are subclinical and amniotic fluid (AF) cultures take several days before results are available. Several tests have been proposed for the rapid diagnosis of microbial invasion of the amniotic cavity (MIAC) or intra-amniotic inflammation. The aim of this study was to examine the diagnostic performance of the AF Mass Restricted (MR) score in comparison with interleukin-6 (IL-6) and matrix metalloproteinase-8 (MMP-8) for the identification of MIAC or inflammation.

METHODS

AF samples were collected from patients with singleton gestations and symptoms of preterm labor (n = 100). Intra-amniotic inflammation was defined as >100 white blood cells/mm(3) (WBCs) in AF; MIAC was defined as a positive AF culture. AF IL-6 and MMP-8 were determined using ELISA. The MR score was obtained using the Surface-Enhanced Laser Desorption Ionization Time of Flight (SELDI-TOF) mass spectrometry. Sensitivity and specificity were calculated and logistic regression models were fit to construct receiver-operating characteristic (ROC) curves for the identification of each outcome. The McNemar's test and paired sample non-parametric statistical techniques were used to test for differences in diagnostic performance metrics.

RESULTS

(1) The prevalence of MIAC and intra-amniotic inflammation was 34% (34/100) and 40% (40/100), respectively; (2) there were no significant differences in sensitivity of the three tests under study (MR score, IL-6 or MMP-8) in the identification of either MIAC or intra-amniotic inflammation (using the following cutoffs: MR score >2, IL-6 >11.4 ng/mL, and MMP-8 >23 ng/mL); (3) there was no significant difference in the sensitivity among the three tests for the same outcomes when the false positive rate was fixed at 15%; (4) the specificity for IL-6 was not significantly different from that of the MR score in identifying either MIAC or intra-amniotic inflammation when using previously reported thresholds; and (5) there were no significant differences in the area under the ROC curve when comparing the MR score, IL-6 or MMP-8 in the identification of these outcomes.

CONCLUSIONS

IL-6 and the MR score have equivalent diagnostic performance in the identification of MIAC or intra-amniotic inflammation. Selection from among these three tests (MR score, IL-6 and MMP-8) for diagnostic purposes should be based on factors such as availability, reproducibility, and cost. The MR score requires a protein chip and a SELDI-TOF instrument which are not widely available or considered "state of the art". In contrast, immunoassays for IL-6 can be performed in the majority of clinical laboratories.

Soluble ST2, a modulator of the inflammatory response, in preterm and term labor

OBJECTIVE

Intra-amniotic infection/inflammation (IAI) is causally linked with spontaneous preterm labor and delivery. The ST2L receptor and its soluble form (sST2) are capable of binding to interleukin (IL)-33, a member of the IL-1 superfamily. Members of this cytokine family have been implicated in the onset of spontaneous preterm labor in the context of infection. Soluble ST2 has anti-inflammatory properties, and plasma concentrations are elevated in systemic inflammation, such as sepsis, acute pyelonephritis in pregnancy and the fetal inflammatory response syndrome. The aims of this study were to examine: (1) whether amniotic fluid concentrations of sST2 change with IAI, preterm, and term parturition; and (2) if mRNA expression of ST2 in the chorioamniotic membranes changes with acute histologic chorioamnionitis in women who deliver preterm.

METHOD

A cross-sectional study was conducted to determine amniotic fluid concentrations of sST2 in: (1) women with preterm labor (PTL) who delivered at term (n=49); (2) women with PTL who delivered preterm without IAI (n=21); (3) women with PTL who delivered preterm with IAI (n=31); (4) term pregnancies not in labor (n=13); and (5) term pregnancies in labor (n=43). The amniotic fluid concentration of sST2 was determined by ELISA. The mRNA expression of ST2 in the chorioamniotic membranes of women who delivered preterm with (n=24), and without acute histologic chorioamnionitis (n=19) was determined by qRT-PCR.

RESULTS

(1) Patients with PTL who delivered preterm with IAI had a lower median amniotic fluid concentration of sST2 compared to those with PTL who delivered preterm without IAI [median 410 ng/mL, inter-quartile range (IQR) 152-699 ng/mL versus median 825 ng/mL, IQR 493-1216 ng/mL; p=0.0003] and those with PTL who delivered at term [median 410 ng/mL, IQR 152-699 ng/mL versus median 673 ng/mL, IQR 468-1045 ng/mL; p=0.0003]; (2) no significant differences in the median amniotic fluid concentration of sST2 were observed between patients with PTL who delivered at term and those who delivered preterm without IAI (p=0.4), and between women at term in labor and those at term not in labor (p=0.9); (3) the mean mRNA expression of ST2 was 4-fold lower in women who delivered preterm with acute histologic chorioamnionitis than in those without this lesion (p=0.008).

CONCLUSIONS

The median sST2 amniotic fluid concentration and mRNA expression of ST2 by chorioamniotic membranes is lower in PTL associated with IAI and acute histologic chorioamnionitis than in PTL without these conditions. Changes in the median amniotic fluid sST2 concentration are not observed in preterm and term parturition without IAI. Thus, amniotic fluid sST2 in the presence of IAI behaves differently when compared to sST2 in the plasma of individuals affected by fetal inflammatory response syndrome, acute pyelonephritis in pregnancy, and adult sepsis. Decreased concentrations of sST2 in IAI are likely to promote a pro-inflammatory response, which is important for parturition in the context of infection.

Soluble ST2 in the fetal inflammatory response syndrome: in vivo evidence of activation of the anti-inflammatory limb of the immune response

OBJECTIVE

Inflammation is a mechanism of host response to infection, which can be harmful when inappropriately modulated. Soluble ST2 (sST2) is a decoy receptor of interleukin (IL)-33, and this complex modulates the balance in the Th1/Th2 immune response. Moreover, sST2 inhibits the production of pro-inflammatory cytokines in cooperation with an anti-inflammatory cytokine, IL-10. The objectives of this study were to: (1) determine whether umbilical cord plasma sST2 concentration differs between preterm neonates with and without funisitis and between those with and without the fetal inflammatory response syndrome (FIRS); and (2) evaluate the relationship between sST2 and IL-10 among neonates with funisitis and/or FIRS.

METHODS

Umbilical cord plasma was collected from neonates delivered prematurely due to preterm labor or preterm prelabor rupture of membranes with (n = 36), and without funisitis (n = 30). FIRS (umbilical cord IL-6 concentration ≥ 17.5 pg/mL) was identified in 29 neonates. Plasma sST2 and IL-10 concentrations were determined by enzyme linked immune sorbent assay.

RESULTS

The median umbilical cord plasma sST2 concentration was 6.7-fold higher in neonates with FIRS than in those without FIRS (median 44.6 ng/mL, interquartile range (IQR) 13.8-80.3 ng/mL versus median 6.7 ng/mL, IQR 5.6-20.1 ng/mL; p < 0.0001). Similarly, the median umbilical cord plasma sST2 concentration was 2.7-fold higher in neonates with funisitis than in those without funisitis (median 19.1 ng/mL; IQR 7.1-75.0 ng/mL versus median 7.2 ng/mL; IQR 5.9-23.1 ng/mL; p = 0.008). There was a strong positive correlation between sST2 and IL-10 in neonates with funisitis and/or FIRS (Spearman's Rho = 0.7, p < 0.0001).

CONCLUSION

FIRS and funisitis are associated with an elevation of umbilical cord plasma concentrations of soluble ST2. This protein represents an important mediator of the immune response in neonates diagnosed with FIRS by promoting an anti-inflammatory effect in association with IL-10.

Endoglin in amniotic fluid as a risk factor for the subsequent development of bronchopulmonary dysplasia

OBJECTIVE

Cross-talk between inflammation and angiogenesis pathways has been recently reported. The objectives of this study were to: (i) examine whether amniotic fluid (AF) concentrations of soluble endoglin (sEng), a protein with anti-angiogenic properties, change during pregnancy, parturition, or intra-amniotic infection and/or inflammation (IAI); (ii) determine whether an increase in sEng in the AF of patients with preterm labor (PTL) and preterm prelabor rupture of membranes (PROM) is associated with adverse neonatal outcomes; and (iii) investigate potential sources of sEng in AF.

STUDY DESIGN

A cross-sectional study was conducted to include patients in the following groups: (i) mid-trimester (n = 20); (ii) PTL with term delivery (n = 95); (iii) PTL leading to preterm delivery with (n = 40) and without IAI (n = 46); (iv) preterm PROM with (n = 37) and without IAI (n = 37); (v) term in labor (n = 48) and not in labor (n = 44). AF concentrations of sEng were determined by enzyme-linked immunosorbent assay. Chorioamniotic membranes, umbilical cord blood, and AF macrophages were examined for the expression of endoglin.

RESULTS

(i) Patients with IAI had a higher median AF concentration of sEng than those without IAI (P = 0.02 for PTL and 0.06 for preterm PROM); (ii) AF concentrations of sEng in the 3rd and 4th quartiles were associated with IAI (OR 2.5 and 7.9, respectively); (iii) an AF sEng concentration ≥779.5 pg/mL was associated with bronchopulmonary dysplasia (BPD) (OR 7.9); (iv) endoglin was co-localized with CD14+ macrophages in AF pellets of patients with IAI by immunofluorescence and flow cytometry; and (v) the concentration of sEng in the supernatant was significantly increased after the treatment of macrophages with endotoxin or TNF-α.

CONCLUSIONS

Soluble endoglin participates in the host response against IAI. Activated macrophages may be a source of sEng concentrations in the AF of patients with IAI. An increase of sEng in the AF is associated with BPD and adverse neonatal outcomes.

The clinical significance of a positive Amnisure test in women with preterm labor and intact membranes

OBJECTIVE

This study was conducted to examine the frequency and clinical significance of a positive Amnisure test in patients with preterm labor and intact membranes by sterile speculum exam.

STUDY DESIGN

A retrospective cohort study was performed including 90 patients with preterm labor and intact membranes who underwent Amnisure tests prior to amniocentesis (< 72 h); most patients (n=64) also underwent fetal fibronectin (fFN) tests. Amniotic fluid (AF) was cultured for aerobic/anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8.

RESULTS

(1) the prevalence of a positive Amnisure test was 19% (17/90); (2) patients with a positive Amnisure test had significantly higher rates of adverse pregnancy and neonatal outcomes (e.g., impending preterm delivery, intra-amniotic infection/inflammation, and neonatal morbidity) than those with a negative Amnisure test; (3) a positive test was associated with significantly increased risk of intra-amniotic infection and/or inflammation, delivery within 7, 14, or 28 days and spontaneous preterm birth (< 35 weeks) among patients with a negative fFN test.

CONCLUSIONS

A positive Amnisure test in patients with preterm labor and intact membranes is a risk factor for adverse pregnancy outcome, particularly in patients with a negative fFN test. A positive Amnisure test in patients without symptoms or signs of ROM should not be taken as an indicator that membranes have ruptured.

Interleukin-19 in fetal systemic inflammation

OBJECTIVE

The fetal inflammatory response syndrome (FIRS) is considered the fetal counterpart of the systemic inflammatory response syndrome (SIRS), which can be caused by infection and non-infection-related insults. Although the initial response is mediated by pro-inflammatory signals, the control of this response is achieved by anti-inflammatory mediators which are essential for the successful outcome of the affected individual. Interleukin (IL)-19 is capable of stimulating the production of IL-10, a major anti-inflammatory cytokine, and is a potent inducer of the T-helper 2 (Th2) response. The aim of this study was to determine if there is a change in umbilical cord plasma IL-19 and IL-10 concentrations in preterm neonates with and without acute funisitis, the histologic counterpart of FIRS.

METHODS

A case-control study was conducted including 80 preterm neonates born after spontaneous labor. Neonates were classified according to the presence (n = 40) or absence of funisitis (n = 40), which is the pathologic hallmark of FIRS. Neonates in each group were also matched for gestational age. Umbilical cord plasma IL-19 and IL-10 concentrations were determined by ELISA.

RESULTS

1) The median umbilical cord plasma IL-19 concentration was 2.5-fold higher in neonates with funisitis than in those without funisitis (median 87 pg/mL; range 20.6-412.6 pg/mL vs. median 37 pg/mL; range 0-101.7 pg/mL; p < 0.001); 2) newborns with funisitis had a significantly higher median umbilical cord plasma IL-10 concentration than those without funisitis (median 4 pg/mL; range 0-33.5 pg/mL vs. median 2 pg/mL; range 0-13.8 pg/mL; p < 0.001); and 3) the results were similar when we included only patients with funisitis who met the definition of FIRS by umbilical cord plasma IL-6 concentrations ≥ 17.5 pg/mL (p < 0.001).

CONCLUSION

IL-19 and IL-10 are parts of the immunologic response of FIRS. A subset of fetuses with FIRS had high umbilical cord plasma IL-19 concentrations. In utero exposure to high systemic concentrations of IL-19 may reprogram the immune response.

Blood pH and gases in fetuses in preterm labor with and without systemic inflammatory response syndrome

OBJECTIVE

Fetal hypoxemia has been proposed to be one of the mechanisms of preterm labor (PTL) and delivery. This may have clinical implications since it may alter: (i) the method/frequency of fetal surveillance and (ii) the indications and duration of tocolysis to an already compromised fetus. The aim of this study was to examine whether there is a difference in the fetal blood gas analysis [pH, PaO(2) and base excess (BE)] and in the prevalence of fetal acidemia and hypoxia between: (i) patients in PTL who delivered within 72 hours vs. those who delivered more than 72 hours after cordocentesis and (ii) patients with fetal inflammatory response syndrome (FIRS) vs. those without this condition.

STUDY DESIGN

Patients admitted with PTL underwent amniocentesis and cordocentesis. Ninety women with singleton pregnancies and PTL were classified according to (i) those who delivered within 72 hours (n = 30) and after 72 hours of the cordocentesis (n = 60) and (ii) with and without FIRS. FIRS was defined as a fetal plasma concentration of IL-6 > 11 pg/mL. Fetal blood gases were determined. Acidemia and hypoxemia were defined as fetal pH and PaO(2) below the 5th percentile for gestational age, respectively. For comparisons between the two study groups, ΔpH and ΔPaO(2) were calculated by adjusting for gestational age (Δ = observed value - mean for gestational age). Non-parametric statistics were employed.

RESULTS

No differences in the median Δ pH (-0.026 vs. -0.016), ΔPaO(2) (0.25 mmHg vs. 5.9 mmHg) or BE (-2.4 vs. -2.6 mEq/L) were found between patients with PTL who delivered within 72 hours and those who delivered 72 hours after the cordocentesis (p > 0.05 for all comparisons). Fetal plasma IL-6 concentration was determined in 63% (57/90) of fetuses and the prevalence of FIRS was 28% (16/57). There was no difference in fetal pH, PaO(2) and BE between fetuses with and without FIRS (p > 0.05 for all comparisons). Moreover, there was no difference in the rate of fetal acidemia between fetuses with and without FIRS (6.3 vs. 9.8%; p > 0.05) and fetal hypoxia between fetuses with or without FIRS (12.5 vs. 19.5%; p > 0.05).

CONCLUSIONS

Our data do not support a role for acute fetal hypoxemia and metabolic acidemia in the etiology of PTL and delivery.

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

INTRODUCTION

Intra-amniotic inflammation is traditionally defined as an elevation of amniotic fluid interleukin (IL)-6. Previous case control studies have suggested an association between an elevated midtrimester amniotic fluid IL-6 and preterm delivery, although such an association has been recently challenged. Intra-amniotic inflammation can also be defined by an elevation of the T-cell chemokine, Interferon-gamma-inducible protein (IP)-10. An elevation in amniotic fluid IP-10 has been associated with chronic chorioamnionitis, a lesion frequently found in late spontaneous preterm birth and fetal death. In contrast, an elevation in amniotic fluid IL-6 is typically associated with acute chorioamnionitis and funisitis. This study was conducted to examine the relationship between an elevation in amniotic fluid IL-6 in the midtrimester and preterm delivery at or before 32 weeks of gestation, and the amniotic fluid concentration of IP-10 and preterm delivery after 32 weeks of gestation.

MATERIALS AND METHODS

This cohort study included 847 consecutive women undergoing genetic midtrimester amniocentesis; in 796 cases, amniotic fluid and pregnancy outcome was available for study after exclusion of abnormal karyotype and/or fetal congenital anomalies. Spontaneous preterm delivery was defined as early (≤32 weeks) or late (after 32 completed weeks of pregnancy). The amniotic fluid and maternal blood concentrations of IL-6 and IP-10 were measured by specific immunoassays.

RESULTS

1) The prevalence of preterm delivery was 8.3% (66/796), while those of early and late spontaneous preterm delivery were 1.5% (n=12), and 4.5% (n=36), respectively; 2) patients who had a spontaneous preterm delivery after 32 weeks of gestation had a higher median amniotic fluid IP-10 concentration than those who delivered at term [median 713 pg/mL, inter-quartile range (IQR) 509-1427 pg/mL vs. median 589 pg/mL, IQR 402-953 pg/mL; P=0.006] and an elevation of amniotic fluid IP-10 concentration above 502 pg/mL (derived from an ROC curve) was associated with late spontaneous preterm delivery [odds ratio 3.9 (95% CI 1.6-9.9)]; 3) patients who had a spontaneous preterm delivery ≤32 weeks of gestation had a higher median amniotic fluid IL-6 concentration than those who delivered at term [median 2052 pg/mL, IQR 435-3015 pg/mL vs. median 414 pg/mL, IQR 209-930 pg/mL; P=0.006], and an elevated amniotic fluid IL-6 concentration above 1740 pg/mL (derived from an ROC curve) was associated with early spontaneous preterm delivery [odds ratio 9.5 (95% CI 2.9-31.1)]; 4) subclinical intra-amniotic inflammation, defined as an elevation of IL-6 (≥2.9 ng/mL) or IP-10 (≥2.2 ng/mL) concentration above the 95th percentile of patients who had uncomplicated term delivery (n=652 for IL-6 and n=633 for IP-10), was observed in 6.3% (50/796) and 5.8% (45/770) of cases, respectively. Although each type of inflammation is a risk factor for spontaneous preterm delivery, many patients had a term delivery without complication; 5) the amniotic fluid in the midtrimester did not contain microorganisms detectable with cultivation techniques.

CONCLUSIONS

INTRA-amniotic inflammation is heterogeneous. Some patients have elevated amniotic fluid concentrations of IL-6, and are at risk for spontaneous preterm delivery before 32 weeks of gestation, while others have an elevated IP-10 (a chemotactic T-cell chemokine) and such patients are at risk for spontaneous preterm delivery after 32 weeks of gestation. A fraction of patients have subclinical intra-amniotic inflammation and deliver at term. The clinical significance of this condition remains to be determined.

The role of granulocyte colony-stimulating factor in the neutrophilia observed in the fetal inflammatory response syndrome

OBJECTIVES

Fetal neutrophilia is present in two-thirds of cases with the fetal inflammatory response syndrome (FIRS). The mechanisms responsible for this finding have not been elucidated. Granulocyte colony-stimulating factor (G-CSF) is the primary physiologic regulator of neutrophil production and plays a key role in the rapid generation and release of neutrophils in stressful conditions (i.e., infection). The objective of this study was to determine: 1) whether FIRS was associated with changes in fetal plasma G-CSF concentrations; and 2) if fetal plasma G-CSF concentrations correlated with fetal neutrophil counts, chorioamnionitis, neonatal morbidity/mortality and cordocentesis-to-delivery interval.

STUDY DESIGN

Percutaneous umbilical cord blood sampling was performed in a population of patients with preterm labor (n=107). A fetal plasma interleukin-6 (IL-6) concentration >11 pg/mL was used to define FIRS. Cord blood G-CSF was measured by a sensitive and specific immunoassay. An absolute neutrophil count was determined and corrected for gestational age. Receiver operating characteristic (ROC) curve, survival analysis and Cox proportional hazard model were employed.

RESULTS

1) G-CSF was detected in all fetal blood samples; 2) fetuses with FIRS had a higher median fetal plasma G-CSF concentration than those without FIRS (P<0.001); 3) a fetal plasma G-CSF concentration ≥134 pg/mL (derived from an ROC curve) was associated with a shorter cordocentesis-to-delivery interval, a higher frequency of chorioamnionitis (clinical and histological), intra-amniotic infection, and composite neonatal morbidity/mortality than a fetal plasma concentration below this cut-off; and 4) a fetal plasma G-CSF concentration ≥134 pg/mL was associated with a shorter cordocentesis-to-delivery interval (hazard ratio 3.2; 95% confidence interval 1.8-5.8) after adjusting for confounders.

CONCLUSIONS

1) G-CSF concentrations are higher in the peripheral blood of fetuses with FIRS than in fetuses without FIRS; and 2) a subset of fetuses with FIRS with elevated fetal plasma G-CSF concentrations are associated with neutrophilia, a shorter procedure-to-delivery interval, chorio-amnionitis and increased perinatal morbidity and mortality.

Magnetic resonance imaging demonstrates long-term changes in brain structure in children born preterm and exposed to chorioamnionitis

OBJECTIVE

We sought to determine if children born preterm and exposed to chorioamnionitis have differences in brain structure measured at 6-10 years of age using magnetic resonance imaging (MRI).

STUDY DESIGN

Structural MRI was performed with 11 preterm children (8.5 ± 1.7 years) with chorioamnionitis and 16 preterm children (8.7 ± 1.4 years) without chorioamnionitis. Cortical surface reconstruction and volumetric segmentation were performed with FreeSurfer image analysis software. Subcortical structures were analyzed using multivariate analysis.

RESULTS

Widespread regional differences in cortical thickness were observed. With chorioamnionitis, the frontal and temporal lobes were primarily affected by decreased cortical thickness, and the limbic, parietal, and occipital lobes were primarily affected by increased cortical thickness when compared to the comparison group. Subcortical differences were observed in the hippocampus and lateral ventricle.

CONCLUSION

Using MRI, chorioamnionitis is associated with longterm widespread regional effects on brain development in children born prematurely. Our study is limited by its small sample size.

Hematologic profile of the fetus with systemic inflammatory response syndrome

OBJECTIVE

The fetal inflammatory response syndrome (FIRS) is associated with impending onset of preterm labor/delivery, microbial invasion of the amniotic cavity and increased perinatal morbidity. FIRS has been defined by an elevated fetal plasma interleukin (IL)-6, a cytokine with potent effects on the differentiation and proliferation of hematopoietic precursors. The objective of this study was to characterize the hematologic profile of fetuses with FIRS.

STUDY DESIGN

Fetal blood sampling was performed in patients with preterm prelabor rupture of membranes and preterm labor with intact membranes (n=152). A fetal plasma IL-6 concentration ≥ 11 pg/mL was used to define FIRS. Hemoglobin concentration, platelet count, total white blood cell (WBC) count, differential count, and nucleated red blood cell (NRBC) count were obtained. Since blood cell count varies with gestational age, the observed values were corrected for fetal age by calculating a ratio between the observed and expected mean value for gestational age.

RESULTS

1) The prevalence of FIRS was 28.9% (44/152); 2) fetuses with FIRS had a higher median corrected WBC and corrected neutrophil count than those without FIRS (WBC: median 1.4, range 0.3-5.6, vs. median 1.1, range 0.4-2.9, P=0.001; neutrophils: median 3.6, range 0.1-57.5, vs. median 1.8, range 0.2-13.9, P<0.001); 3) neutrophilia (defined as a neutrophil count >95th centile of gestational age) was significantly more common in fetuses with FIRS than in those without FIRS (71%, 30/42, vs. 35%, 37/105; P<0.001); 4) more than two-thirds of fetuses with FIRS had neutrophilia, whereas neutropenia was present in only 4.8% (2/42); 5) FIRS was not associated with detectable changes in hemoglobin concentration, platelet, lymphocyte, monocyte, basophil or eosinophil counts; and 6) fetuses with FIRS had a median corrected NRBC count higher than those without FIRS. However, the difference did not reach statistical significance (NRBC median 0.07, range 0-1.3, vs. median 0.04, range 0-2.3, P=0.06).

CONCLUSION

The hematologic profile of the human fetus with FIRS is characterized by significant changes in the total WBC and neutrophil counts. The NRBC count in fetuses with FIRS tends to be higher than fetuses without FIRS.

[Cerebral palsy and perinatal asphyxia (II--Medicolegal implications and prevention)]

Obstetric litigation is a growing problem in developed countries and its escalating cost together with increasing medical insurance premiums is a major concern for maternity service providers, leading to obstetric practice cessation by many practitioners. Fifty-four to 74 % of claims are based on cardiotocographic (CTG) abnormalities and their interpretation followed by inappropriate or delayed reactions. A critical analysis is performed about the nine criteria identified by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics in their task force on Neonatal Encephalopathy and Cerebral Palsy: four essential criteria defining neonatal asphyxia and five other suggesting an acute intrapartum event sufficient to cause cerebral palsy in term newborns. The importance of placental histologic examination is emphasized in order to confirm sudden catastrophic events occurring before or during labor or to detect occult thrombotic processes affecting the fetal circulation, patterns of decreased placenta reserve and adaptative responses to chronic hypoxia. It may also exclude intrapartum hypoxia by revealing some histologic patterns typical of acute chorioamnionitis and fetal inflammatory response or compatible with metabolic diseases. Magnetic resonance imaging (MRI) of the infant's damaged brain is very contributive to elucidate the mechanism and timing of asphyxia in conjunction with the clinical picture, by locating cerebral injuries predominantly in white or grey matter. Intrapartum asphyxia is sometimes preventable by delivering weak fetuses by cesarean sections before birth, by avoiding some "sentinel" events, and essentially by responding appropriately to CTG anomalies and performing an efficient neonatal resuscitation. During litigation procedures, it is necessary to have access to a readable CTG, a well-documented partogram, a complete analysis of umbilical cord gases, a placental pathology and an extensive clinical work-up of the newborn infant including cerebral MRI. Malpractice litigation in obstetric care can be reduced by permanent CTG education, respect of national CTG guidelines, use of adjuncts such as fetal blood sampling for pH or lactates, regular review of adverse events in Clinical Risk Management (CRM) groups and periodic audits about low arterial cord pH in newborns, admission to neonatal unit, the need for assisted ventilation and the decision-to-delivery interval for emergency operative deliveries. Considering the fast occurrence of fetal cerebral hypoxic injuries, and thus despite an adequate management, many intrapartum asphyxias will not be preventable. Conversely, well-documented hypoxic-ischemic brain insults during the antenatal period do not automatically exclude intrapartum suboptimal obstetric care.

The effect of magnesium sulfate on the activity of matrix metalloproteinase-9 in fetal cord plasma and human umbilical vein endothelial cells

OBJECTIVE

Clinical evidence suggests that magnesium sulfate may reduce the risk of fetal neurologic injury in preterm delivery. Matrix metalloproteinase-9 (MMP-9) levels are elevated in preterm labor patients. There is evidence that MMP-9 may break down the blood-brain barrier in humans, causing cytokine mediated cell injury. Our objective was to determine whether the addition of magnesium sulfate attenuates activity of MMP-9, a complex zinc-dependent enzyme, in fetal cord plasma.

STUDY DESIGN

We collected cord plasma in 6 term, unlabored patients. Using enzyme-linked immunosorbent assay, we measured the activity of MMP-9 with varying concentrations of magnesium sulfate added in vitro. Results were verified using a human umbilical cord vein endothelial cell (HUVEC) line.

RESULTS

Addition of physiologic doses of magnesium sulfate (0.07 mg/mL) resulted in a 25% decrease in active MMP-9 (P = .03). In a HUVEC line, magnesium sulfate resulted in a 32% decrease in MMP-9 activity (P = .00012).

CONCLUSION

The addition of magnesium sulfate attenuated MMP-9 activity in cord plasma and in a HUVEC line.

Pentraxin 3 in amniotic fluid: a novel association with intra-amniotic infection and inflammation

OBJECTIVE

Pentraxin 3 (PTX3) is a soluble pattern recognition receptor (PRR) that has an important role in immunoregulation and vascular integrity. The aim of this study was to determine if PTX3 is present in amniotic fluid (AF) and whether its concentration changes with gestational age (GA), in the presence of preterm or term labor, and in cases of intra-amniotic infection/inflammation (IAI) associated with spontaneous preterm labor (PTL) or preterm prelabor rupture of membranes (PROM).

STUDY DESIGN

This cross-sectional study included the following groups: 1) mid-trimester (n=45); 2) uncomplicated pregnancies at term with (n=48) and without (n=40) spontaneous labor; 3) women with PTL and intact membranes who: a) delivered at term (n=44); b) delivered preterm without IAI (n=40); or c) delivered preterm with IAI (n=62); 4) women with preterm PROM with (n=63) and without (n=36) IAI. PTX3 concentration in AF was determined by ELISA. Non-parametric statistics were used for analyses.

RESULTS

1) Among women with PTL and intact membranes, the median AF PTX3 concentration was significantly higher in women with IAI than in those without IAI (7.95 ng/mL vs. 0.38 ng/mL; P<0.001) and than in those who delivered at term (0.55 ng/mL; P<0.001); 2) women with preterm PROM and IAI had a higher median AF PTX3 concentration than those without IAI (9.12 ng/mL vs. 0.76 ng/mL; P<0.001); 3) the median AF PTX3 concentration did not change with GA (mid-trimester: 0.79 ng/mL vs. term not in labor: 0.58 ng/mL; P=0.09); and 4) labor at term was not associated with a significant change of AF PTX 3 concentration (in labor: 0.54 ng/mL vs. not in labor: 0.58 ng/mL, P=0.9).

CONCLUSIONS

PTX3 is a physiologic constituent of the AF, and its median concentration is elevated in the presence of IAI, suggesting that PTX3 may play a role in the innate immune response against IAI.

The transcriptome of the fetal inflammatory response syndrome

PROBLEM

The fetal inflammatory response syndrome (FIRS) is considered the counterpart of the systemic inflammatory response syndrome (SIRS), but similarities in their regulatory mechanisms are unclear. This study characterizes the fetal mRNA transcriptome of peripheral leukocytes to identify key biological processes and pathways involved in FIRS.

METHOD OF STUDY

Umbilical cord blood from preterm neonates with FIRS (funisitis, plasma IL-6 >11 pg/mL; n = 10) and neonates with no evidence of inflammation (n = 10) was collected at birth. Results Microarray analysis of leukocyte RNA revealed differential expression of 541 unique genes, changes confirmed by qRT-PCR for 41 or 44 genes tested. Similar to SIRS and sepsis, ontological and pathway analyses yielded significant enrichment of biological processes including antigen processing and presentation, immune response, and processes critical to cellular metabolism.

RESULTS

are comparable with microarray studies of endotoxin challenge models and pediatric sepsis, identifying 25 genes across all studies.

CONCLUSION

This study is the first to profile genome-wide expression in FIRS, which demonstrates a substantial degree of similarity with SIRS despite differences in fetal and adult immune systems.

[Fetal membranes: embryological development, structure and the physiopathology of the preterm premature rupture of membranes]

Fetal membranes development is a complex process. The amniotic and exo-celomic cavities are appearing first. The rapid growth of the amniotic cavity is leading to the disappearance of the exo-celomic cavity and the chorion is merging with the decidua. Fetal membranes consist of three layers: the amnion and the chorion, issued from fetal tissues and the decidua issued from maternal tissue. A balance between the synthesis and the degradation of membranes components is physiologic throughout the gestation. Two main mechanisms are involved in the degradation process: apoptosis in the cellular compartment and matrix metalloproteinase (MMP) in the extracellular matrix. Regulation of MMP is depending on factors increasing their expression (cytokines) and factors decreasing their activity tissue inhibitor of metalloproteinases (TIMPS). Particular conditions can induce an unbalance between synthesis and degradation leading to the weakening of the membranes. Different factors can be associated to induce this unbalance: infection, hormonal factors, default in membranes fusion, oxidative stress and mechanic factors. In fine, the spontaneous rupture of the membranes is always occurring in regard of the uterine cervix after a process started several weeks before.

Proteomic analysis of amniotic fluid to identify women with preterm labor and intra-amniotic inflammation/infection: the use of a novel computational method to analyze mass spectrometric profiling

OBJECTIVE

Examination of the amniotic fluid proteome has been used to identify biomarkers for intra-amniotic inflammation as well as those that may be useful in predicting the outcome of preterm labor. The purpose of this study was to combine a novel computational method of pattern discovery with mass spectrometric proteomic profiling of amniotic fluid to discover biomarkers of intra-amniotic infection/inflammation (IAI).

METHODS

This cross-sectional study included patients with spontaneous preterm labor and intact membranes who delivered at term (n = 59) and those who delivered preterm with IAI (n = 60). Proteomic profiling was performed using surface-enhanced laser desorption/ionization (SELDI) mass spectrometry. A proteomic profile was acquired through multiple simultaneous SELDI conditions, which were combined in a single proteomic 'fingerprint' using a novel computational approach. Classification of patients based on their associated surface-enhanced laser desorption/ionization-time of flight (SELDI-TOF) mass spectra as belonging to either the class of individuals with preterm delivery with IAI or term delivery was accomplished by constructing an empirical model. The first phase in the construction of this empirical model involved the selection of adjustable parameters utilizing a training/testing subset of data. The second phase tested the generalization of the model by utilizing a blinded validation set of patients who were not employed in parameter selection.

RESULTS

Gestational age at amniocentesis was not significantly different between the groups. Thirty-nine unique mass spectrometric peaks discriminated patients with preterm labor/delivery with IAI from those with preterm labor and term delivery. In the testing/training dataset, the classification accuracies (averaged over 100 random draws) were: 91.4% (40.2/44) for patients with preterm delivery with IAI, and 91.2% (40.1/44) for term delivery. The overall accuracy of the classification of patients in the validation dataset was 90.3% (28/31).

CONCLUSIONS

Proteomic analysis of amniotic fluid allowed the identification of mass spectrometry features, which can distinguish patients with preterm labor with IAI from those with preterm labor without inflammation or infection who subsequently delivered at term.

The fetal inflammatory response syndrome

The fetal inflammatory response syndrome (FIRS) is a condition characterized by systemic inflammation and an elevation of fetal plasma interleukin-6. This syndrome has been observed in fetuses with preterm labor with intact membranes, preterm prelabor rupture of the membranes, and also fetal viral infections such as cytomegalovirus. FIRS is a risk factor for short-term perinatal morbidity and mortality after adjustment for gestational age at delivery and also for the development of long-term sequelae such as bronchopulmonary dysplasia and brain injury. Multiorgan involvement in FIRS has been demonstrated in the hematopoietic system, thymus, adrenal glands, skin, kidneys, heart, lung, and brain. This article reviews the fetal systemic inflammatory response as a mechanism of disease. Potential interventions to control an exaggerated inflammatory response in utero are also described.

Neonatal brain damage following prolonged latency after preterm premature rupture of membranes

This study evaluated the risk of brain damage in neonates delivered at < 34 weeks following a prolonged latency after preterm premature rupture of membranes (pPROM). The medical records of 77 singletons delivered at < 34 weeks with pPROM and 66 singletons delivered at < 34 weeks with preterm labor and intact membranes were reviewed. Latency was divided into four intervals: < or = 24, > 24-< or = 72, > 72- < or = 168 hr, and > 1 week. Outcomes in the longer three intervals were compared with those in neonates delivered at < or = 24 hr after pPROM. The documented outcomes were placental (histologic chorioamnionitis, vasculitis, funnisitis) and neonatal (intraventricular hemorrhage, ventriculomegaly, germinal matrix hemorrhage, periventricular leukomalacia). Odds ratios and 95% CI for the risk of histologic chorioamnionitis according to the respective latency intervals were 4.8 (1.0-22.9), 7.0 (1.1-43.1), 7.4 (2.1-42.3) in patients with pPROM. The risks of intracranial ultrasonic abnormalities, however, did not increased with prolonged latency. In the patients with preterm labor and intact membranes, the both risks did not increased with increasing latency. Therefore, this study was suggested that the risk of histologic chorioamnionitis increased with increasing latency, but there was no relationship between neonatal brain damage and latency interval after pPROM.

Inflammatory brain damage in preterm newborns--dry numbers, wet lab, and causal inferences

Epidemiologic observations support the contention that infection, inflammation, and neonatal white matter damage (WMD) are associated. We also have documentation from multiple experimental models that infection/inflammation can damage developing white matter. Based on these observations in humans and animals, we offer causal inferences using widely accepted causal criteria and the multivariable model of causation. As much as we want to, however, we are reluctant to state unequivocally that inflammation causes WMD in humans born much before term. The main reason is that we lack convincing evidence that inflammation precedes WMD (temporal evidence). We also need more (and more detailed) observational studies clarifying the presumed infection --> inflammation --> WMD sequence before we can initiate intervention trials to reduce the risk of WMD.