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

BACKGROUND: One of every four preterm neonates is born to a woman with sterile intra-amniotic inflammation (inflammatory process induced by alarmins); yet, this clinical condition still lacks treatment. Herein, we utilized an established murine model of sterile intra-amniotic inflammation induced by the alarmin high-mobility group box-1 (HMGB1) to evaluate whether treatment with clarithromycin prevents preterm birth and adverse neonatal outcomes by dampening maternal and fetal inflammatory responses. METHODS: Pregnant mice were intra-amniotically injected with HMGB1 under ultrasound guidance and treated with clarithromycin or vehicle control, and pregnancy and neonatal outcomes were recorded (n = 15 dams each). Additionally, amniotic fluid, placenta, uterine decidua, cervix, and fetal tissues were collected prior to preterm birth for determination of the inflammatory status (n = 7-8 dams each). RESULTS: Clarithromycin extended the gestational length, reduced the rate of preterm birth, and improved neonatal mortality induced by HMGB1. Clarithromycin prevented preterm birth by interfering with the common cascade of parturition as evidenced by dysregulated expression of contractility-associated proteins and inflammatory mediators in the intra-uterine tissues. Notably, clarithromycin improved neonatal survival by dampening inflammation in the placenta as well as in the fetal lung, intestine, liver, and spleen. CONCLUSIONS: Clarithromycin prevents preterm birth and improves neonatal survival in an animal model of sterile intra-amniotic inflammation, demonstrating the potential utility of this macrolide for treating women with this clinical condition, which currently lacks a therapeutic intervention.

Fetal T Cell Activation in the Amniotic Cavity during Preterm Labor: A Potential Mechanism for a Subset of Idiopathic Preterm Birth.

Prematurity is the leading cause of perinatal morbidity and mortality worldwide. In most cases, preterm birth is preceded by spontaneous preterm labor, a syndrome that is associated with intra-amniotic inflammation, the most studied etiology. However, the remaining etiologies of preterm labor are poorly understood; therefore, most preterm births are categorized as idiopathic. In this study, we provide evidence showing that the fetal immune system undergoes premature activation in women with preterm labor without intra-amniotic inflammation, providing a potential new mechanism of disease for some cases of idiopathic preterm birth. First, we showed that fetal T cells are a predominant leukocyte population in amniotic fluid during preterm gestations. Interestingly, only fetal CD4+ T cells were increased in amniotic fluid of women who underwent idiopathic preterm labor and birth. This increase in fetal CD4+ T cells was accompanied by elevated amniotic fluid concentrations of T cell cytokines such as IL-2, IL-4, and IL-13, which are produced by these cells upon in vitro stimulation, but was not associated with the prototypical cytokine profile observed in women with intra-amniotic inflammation. Also, we found that cord blood T cells, mainly CD4+ T cells, obtained from women with idiopathic preterm labor and birth displayed enhanced ex vivo activation, which is similar to that observed in women with intra-amniotic inflammation. Finally, we showed that the intra-amniotic administration of activated neonatal CD4+ T cells induces preterm birth in mice. Collectively, these findings provide evidence suggesting that fetal T cell activation is implicated in the pathogenesis of idiopathic preterm labor and birth.

Effector and Activated T Cells Induce Preterm Labor and Birth That Is Prevented by Treatment with Progesterone.

Preterm labor commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. Most research has focused on establishing a causal link between innate immune activation and pathological inflammation leading to preterm labor and birth. However, the role of maternal effector/activated T cells in the pathogenesis of preterm labor/birth is poorly understood. In this study, we first demonstrated that effector memory and activated maternal T cells expressing granzyme B and perforin are enriched at the maternal-fetal interface (decidua) of women with spontaneous preterm labor. Next, using a murine model, we reported that prior to inducing preterm birth, in vivo T cell activation caused maternal hypothermia, bradycardia, systemic inflammation, cervical dilation, intra-amniotic inflammation, and fetal growth restriction, all of which are clinical signs associated with preterm labor. In vivo T cell activation also induced B cell cytokine responses, a proinflammatory macrophage polarization, and other inflammatory responses at the maternal-fetal interface and myometrium in the absence of an increased influx of neutrophils. Finally, we showed that treatment with progesterone can serve as a strategy to prevent preterm labor/birth and adverse neonatal outcomes by attenuating the proinflammatory responses at the maternal-fetal interface and cervix induced by T cell activation. Collectively, these findings provide mechanistic evidence showing that effector and activated T cells cause pathological inflammation at the maternal-fetal interface, in the mother, and in the fetus, inducing preterm labor and birth and adverse neonatal outcomes. Such adverse effects can be prevented by treatment with progesterone, a clinically approved strategy.

Betamethasone as a potential treatment for preterm birth associated with sterile intra-amniotic inflammation: a murine study.

OBJECTIVES: Preterm birth remains the leading cause of perinatal morbidity and mortality worldwide. Preterm birth is preceded by spontaneous preterm labor, which is commonly associated with sterile intra-amniotic inflammation; yet, no approved treatment exists for this clinical condition. Corticosteroids are the standard of care to improve neonatal outcomes in women at risk of preterm birth. Herein, we first validated our model of alarmin-induced preterm birth. Next, we investigated whether treatment with betamethasone could prevent preterm birth resulting from sterile intra-amniotic inflammation in mice. METHODS: Under ultrasound guidance, the first cohort of dams received an intra-amniotic injection of the alarmin high-mobility group box-1 (HMGB1, n=10) or phosphate-buffered saline (PBS, n=9) as controls. A second cohort of dams received HMGB1 intra-amniotically and were subcutaneously treated with betamethasone (n=15) or vehicle (n=15). Dams were observed until delivery, and perinatal outcomes were observed. RESULTS: Intra-amniotic HMGB1 reduced gestational length (p=0.04), inducing preterm birth in 40% (4/10) of cases, of which 100% (4/4) were categorized as late preterm births. Importantly, treatment with betamethasone extended the gestational length (p=0.02), thereby reducing the rate of preterm birth by 26.6% (from 33.3% [5/15] to 6.7% [1/15]). Treatment with betamethasone did not worsen the rate of neonatal mortality induced by HMGB1 or alter weight gain in the first three weeks of life. CONCLUSIONS: Treatment with betamethasone prevents preterm birth induced by the alarmin HMGB1. This study supports the potential utility of betamethasone for treating women with sterile intra-amniotic inflammation.

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care.

OBJECTIVES: Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia. METHODS: This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL. RESULTS: (1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases. CONCLUSIONS: Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

Cellular immune responses in amniotic fluid of women with preterm prelabor rupture of membranes.

Background Preterm birth is the leading cause of perinatal morbidity and mortality. Preterm prelabor rupture of membranes (pPROM) occurs in 30% of preterm births; thus, this complication is a major contributor to maternal and neonatal morbidity. However, the cellular immune responses in amniotic fluid of women with pPROM have not been investigated. Methods Amniotic fluid samples were obtained from women with pPROM and a positive (n = 7) or negative (n = 10) microbiological culture. Flow cytometry was performed to evaluate the phenotype and number of amniotic fluid leukocytes. The correlation between amniotic fluid immune cells and an interleukin-6 (IL-6) concentration or a white blood cell (WBC) count in amniotic fluid was calculated. Results Women with pPROM and a positive amniotic fluid culture had (1) a greater number of total leukocytes in amniotic fluid, including neutrophils and monocytes/macrophages and (2) an increased number of total T cells in amniotic fluid, namely CD4+ T cells and CD8+ T cells, but not B cells. The numbers of neutrophils and monocytes/macrophages were positively correlated with IL-6 concentrations and WBC counts in amniotic fluid of women with pPROM. Conclusion Women with pPROM and a positive amniotic fluid culture exhibit a more severe cellular immune response than those with a negative culture, which is associated with well-known markers of intra-amniotic inflammation.

QUEST MRI assessment of fetal brain oxidative stress in utero.

PURPOSE: To achieve sufficient precision of R1 (=1/T1) maps of the fetal brain in utero to perform QUEnch-assiSTed (QUEST) MRI in which a significant anti-oxidant-induced reduction in R1 indicates oxidative stress. METHODS: C57BL/6 mouse fetuses in utero were gently and non-surgically isolated and secured using a homemade 3D printed clip. Using a commercial receive-only surface coil, brain maps of R1, an index sensitive to excessive and continuous free radical production, were collected using either a conventional Cartesian or a non-Cartesian (periodically rotated overlapping parallel lines with enhanced reconstruction) progressive saturation sequence. Data were normalized to the shortest TR time to remove bias. To assess oxidative stress, brain R1 maps were acquired on the lipopolysaccharide (LPS) model of preterm birth ±â€¯rosiglitazone (ROSI, which has anti-oxidant properties); phosphate buffered saline (PBS) controls ±â€¯ROSI were similarly studied. RESULTS: Sufficient quality R1 maps were generated by a combination of the 3D printed clip, surface coil detection, non-Cartesian sequence, and normalization scheme ensuring minimal fetal movement, good detection sensitivity, reduced motion artifacts, and minimal baseline variations, respectively. In the LPS group, the combined caudate-putamen and thalamus region R1 was reduced (p < 0.05) with ROSI treatment consistent with brain oxidative stress; no evidence for oxidative stress was found in the pons region. In the PBS control group, brain R1's did not change with ROSI treatment. CONCLUSION: The sensitivity and reproducibility of the combined approaches described herein enabled first-time demonstration of regional oxidative stress measurements of the fetal brain in utero using QUEST MRI.

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

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

The Impact of Time Interval between Extubation and Reintubation on Death or Bronchopulmonary Dysplasia in Extremely Preterm Infants.

OBJECTIVE: To explore the relation between time to reintubation and death or bronchopulmonary dysplasia (BPD) in extremely preterm infants. STUDY DESIGN: This was a subanalysis from an ongoing multicenter observational study. Infants with birth weight ≤1250 g, requiring mechanical ventilation, and undergoing their first elective extubation were prospectively followed throughout hospitalization. Time to reintubation was defined as the time interval between first elective extubation and reintubation. Univariate and multivariate logistic regression analyses were performed to evaluate associations between time to reintubation, using different observation windows after extubation (24-hour intervals), and death/BPD (primary outcome) or BPD among survivors (secondary outcome). aORs were computed with and without the confounding effects of cumulative mechanical ventilation duration. RESULTS: Of 216 infants included for analysis, 103 (48%) were reintubated at least once after their first elective extubation. Reintubation was associated with lower gestational age/weight and greater morbidities compared with infants never reintubated. After adjusting for confounders, reintubation within observation windows ranging between 24 hours and 3 weeks postextubation was associated with increased odds of death/BPD (but not BPD among survivors), independent of the cumulative mechanical ventilation duration. Reintubation within 48 hours from extubation conferred higher risk-adjusted odds of death/BPD vs other observation windows. CONCLUSIONS: Although reintubation after elective extubation was independently associated with increased likelihood of death/BPD in extremely preterm infants, the greatest risk was attributable to reintubation within the first 48 hours postextubation. Prediction models capable of identifying the highest-risk infants may further improve outcomes.

Mechanisms of death in structurally normal stillbirths.

Objectives To investigate mechanisms of in utero death in normally formed fetuses by measuring amniotic fluid (AF) biomarkers for hypoxia (erythropoietin [EPO]), myocardial damage (cardiac troponin I [cTnI]) and brain injury (glial fibrillary acidic protein [GFAP]), correlated with risk factors for fetal death and placental histopathology. Methods This retrospective, observational cohort study included intrauterine deaths with transabdominal amniocentesis prior to induction of labor. Women with a normal pregnancy and an indicated amniocentesis at term were randomly selected as controls. AF was assayed for EPO, cTnI and GFAP using commercial immunoassays. Placental histopathology was reviewed, and CD15-immunohistochemistry was used. Analyte concentrations >90th centile for controls were considered "raised". Raised AF EPO, AF cTnI and AF GFAP concentrations were considered evidence of hypoxia, myocardial and brain injury, respectively. Results There were 60 cases and 60 controls. Hypoxia was present in 88% (53/60), myocardial damage in 70% (42/60) and brain injury in 45% (27/60) of fetal deaths. Hypoxic fetuses had evidence of myocardial injury, brain injury or both in 77% (41/53), 49% (26/53) and 13% (7/53) of cases, respectively. Histopathological evidence for placental dysfunction was found in 74% (43/58) of these cases. Conclusion Hypoxia, secondary to placental dysfunction, was found to be the mechanism of death in the majority of fetal deaths among structurally normal fetuses. Ninety-one percent of hypoxic fetal deaths sustained brain, myocardial or both brain and myocardial injuries in utero. Hypoxic myocardial injury was an attributable mechanism of death in 70% of the cases. Non-hypoxic cases may be caused by cardiac arrhythmia secondary to a cardiac conduction defect.

The origin of amniotic fluid monocytes/macrophages in women with intra-amniotic inflammation or infection.

Background Monocytes, after neutrophils, are the most abundant white blood cells found in the amniotic cavity of women with intra-amniotic inflammation/infection. However, the origin of such cells has not been fully investigated. Herein, we determined (1) the origin of amniotic fluid monocytes/macrophages from women with intra-amniotic inflammation/infection, (2) the relationship between the origin of amniotic fluid monocytes/macrophages and preterm or term delivery and (3) the localization of monocytes/macrophages in the placental tissues. Methods Amniotic fluid samples (n = 16) were collected from women with suspected intra-amniotic inflammation or infection. Amniotic fluid monocytes/macrophages were purified by fluorescence-activated cell sorting, and DNA fingerprinting was performed. Blinded placental histopathological evaluations were conducted. Immunohistochemistry was performed to detect CD14+ monocytes/macrophages in the placental tissues. Results DNA fingerprinting revealed that (1) 56.25% (9/16) of amniotic fluid samples had mostly fetal monocytes/macrophages, (2) 37.5% (6/16) had predominantly maternal monocytes/macrophages and (3) one sample (6.25% [1/16]) had a mixture of fetal and maternal monocytes/macrophages. (4) Most samples with predominantly fetal monocytes/macrophages were from women who delivered early preterm neonates (77.8% [7/9]), whereas all samples with mostly maternal monocytes/macrophages or a mixture of both were from women who delivered term or late preterm neonates (100% [7/7]). (5) Most of the women included in this study presented acute maternal and fetal inflammatory responses in the placenta (85.7% [12/14]). (6) Women who had mostly fetal monocytes/macrophages in amniotic fluid had abundant CD14+ cells in the umbilical cord and chorionic plate, whereas women with mostly maternal amniotic fluid monocytes/macrophages had abundant CD14+ cells in the chorioamniotic membranes. Conclusion Amniotic fluid monocytes/macrophages can be of either fetal or maternal origin, or a mixture of both, in women with intra-amniotic inflammation or infection. These immune cells could be derived from the fetal and maternal vasculature of the placenta.

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

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

Evidence that intra-amniotic infections are often the result of an ascending invasion - a molecular microbiological study.

Background Microbial invasion of the amniotic cavity resulting in intra-amniotic infection is associated with obstetrical complications such as preterm labor with intact or ruptured membranes, cervical insufficiency, as well as clinical and histological chorioamnionitis. The most widely accepted pathway for intra-amniotic infection is the ascension of microorganisms from the lower genital tract. However, hematogenous dissemination of microorganisms from the oral cavity or intestine, retrograde seeding from the peritoneal cavity through the fallopian tubes, and introduction through invasive medical procedures have also been suggested as potential pathways for intra-amniotic infection. The primary reason that an ascending pathway is viewed as most common is that the microorganisms most often detected in the amniotic fluid are those that are typical inhabitants of the vagina. However, thus far, no studies have shown that microorganisms in the amniotic cavity are simultaneously present in the vagina of the woman from which they were isolated. The objective of the study was to determine the frequency with which microorganisms isolated from women with intra-amniotic infection are also present in the lower genital tract. Methods This was a cross-sectional study of women with intra-amniotic infection with intact membranes. Intra-amniotic infection was defined as a positive culture and elevated concentrations of interleukin-6 (IL-6) (>2.6 ng/mL) in amniotic fluid and/or acute histologic chorioamnionitis and funisitis. Microorganisms isolated from bacterial cultures of amniotic fluid were taxonomically identified through matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and 16S ribosomal RNA (rRNA) gene sequencing. Vaginal swabs were obtained at the time of amniocentesis for the identification of microorganisms in the lower genital tract. The overall bacterial profiles of amniotic fluids and vaginal swabs were characterized through 16S rRNA gene sequencing. The bacterial profiles of vaginal swabs were interrogated for the presence of bacteria cultured from amniotic fluid and for the presence of prominent (>1% average relative abundance) operational taxonomic units (OTUs) within the overall 16S rRNA gene bacterial profiles of amniotic fluid. Results (1) A total of 75% (6/8) of women had bacteria cultured from their amniotic fluid that are typical residents of the vaginal ecosystem. (2) A total of 62.5% (5/8) of women with bacteria cultured from their amniotic fluid also had these bacteria present in their vagina. (3) The microorganisms cultured from amniotic fluid and also detected in the vagina were Ureaplasma urealyticum, Escherichia coli, and Streptococcus agalactiae. (4) 16S rRNA gene sequencing revealed that the amniotic fluid of women with intra-amniotic infection had bacterial profiles dominated by Sneathia, Ureaplasma, Prevotella, Lactobacillus, Escherichia, Gardnerella, Peptostreptococcus, Peptoniphilus, and Streptococcus, many of which had not been cultured from the amniotic fluid samples. (5) Seventy percent (7/10) of the prominent (>1% average relative abundance) OTUs found in amniotic fluid were also prominent in the vagina. Conclusion The majority of women with intra-amniotic infection had bacteria cultured from their amniotic fluid that were typical vaginal commensals, and these bacteria were detected within the vagina at the time of amniocentesis. Molecular microbiological interrogation of amniotic fluid from women with intra-amniotic infection revealed that the bacterial profiles of amniotic fluid were largely consistent with those of the vagina. These findings indicate that ascension from the lower genital tract is the primary pathway for intra-amniotic infection.

Patterns of reintubation in extremely preterm infants: a longitudinal cohort study.

BackgroundThe optimal approach for reporting reintubation rates in extremely preterm infants is unknown. This study aims to longitudinally describe patterns of reintubation in this population over a broad range of observation windows following extubation.MethodsTiming and reasons for reintubation following a first planned extubation were collected from infants with birth weight ≤1,250 g. An algorithm was generated to discriminate between reintubations attributable to respiratory and non-respiratory causes. Frequency and cumulative distribution curves were constructed for each category using 24 h intervals. The ability of observation windows to capture respiratory-related reintubations while limiting non-respiratory reasons was assessed using a receiver operating characteristic curve.ResultsOut of 194 infants, 91 (47%) were reintubated during hospitalization; 68% for respiratory and 32% for non-respiratory reasons. Respiratory-related reintubation rates steadily increased from 0 to 14 days post-extubation before reaching a plateau. In contrast, non-respiratory reintubations were negligible in the first post-extubation week, but became predominant after 14 days. An observation window of 7 days captured 77% of respiratory-related reintubations while only including 14% of non-respiratory cases.ConclusionReintubation patterns are highly variable and affected by the reasons for reintubation and observation window used. Ideally, reintubation rates should be reported using a cumulative distribution curve over time.

Invariant NKT Cell Activation Induces Late Preterm Birth That Is Attenuated by Rosiglitazone.

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. Although intra-amniotic infection is a recognized cause of spontaneous preterm labor, the noninfection-related etiologies are poorly understood. In this article, we demonstrated that the expansion of activated CD1d-restricted invariant NKT (iNKT) cells in the third trimester by administration of α-galactosylceramide (α-GalCer) induced late PTB and neonatal mortality. In vivo imaging revealed that fetuses from mice that underwent α-GalCer-induced late PTB had bradycardia and died shortly after delivery. Yet, administration of α-GalCer in the second trimester did not cause pregnancy loss. Peroxisome proliferator-activated receptor (PPAR)γ activation, through rosiglitazone treatment, reduced the rate of α-GalCer-induced late PTB and improved neonatal survival. Administration of α-GalCer in the third trimester suppressed PPARγ activation, as shown by the downregulation of Fabp4 and Fatp4 in myometrial and decidual tissues, respectively; this suppression was rescued by rosiglitazone treatment. Administration of α-GalCer in the third trimester induced an increase in the activation of conventional CD4(+) T cells in myometrial tissues and the infiltration of activated macrophages, neutrophils, and mature dendritic cells to myometrial and/or decidual tissues. All of these effects were blunted after rosiglitazone treatment. Administration of α-GalCer also upregulated the expression of inflammatory genes at the maternal-fetal interface and systemically, and rosiglitazone treatment partially attenuated these responses. Finally, an increased infiltration of activated iNKT-like cells in human decidual tissues is associated with noninfection-related preterm labor/birth. Collectively, these results demonstrate that iNKT cell activation in vivo leads to late PTB by initiating innate and adaptive immune responses and suggest that the PPARγ pathway has potential as a target for prevention of this syndrome.

Chronic inflammatory lesions of the placenta are associated with an up-regulation of amniotic fluid CXCR3: A marker of allograft rejection.

OBJECTIVE: The objective of this study is to determine whether the amniotic fluid (AF) concentration of soluble CXCR3 and its ligands CXCL9 and CXCL10 changes in patients whose placentas show evidence of chronic chorioamnionitis or other placental lesions consistent with maternal anti-fetal rejection. METHODS: This retrospective case-control study included 425 women with (1) preterm delivery (n=92); (2) term in labor (n=68); and (3) term not in labor (n=265). Amniotic fluid CXCR3, CXCL9 and CXCL10 concentrations were determined by ELISA. RESULTS: (1) Amniotic fluid concentrations of CXCR3 and its ligands CXCL9 and CXCL10 are higher in patients with preterm labor and maternal anti-fetal rejection lesions than in those without these lesions [CXCR3: preterm labor and delivery with maternal anti-fetal rejection placental lesions (median, 17.24 ng/mL; IQR, 6.79-26.68) vs. preterm labor and delivery without these placental lesions (median 8.79 ng/mL; IQR, 4.98-14.7; P=0.028)]; (2) patients with preterm labor and chronic chorioamnionitis had higher AF concentrations of CXCL9 and CXCL10, but not CXCR3, than those without this lesion [CXCR3: preterm labor with chronic chorioamnionitis (median, 17.02 ng/mL; IQR, 5.57-26.68) vs. preterm labor without chronic chorioamnionitis (median, 10.37 ng/mL; IQR 5.01-17.81; P=0.283)]; (3) patients with preterm labor had a significantly higher AF concentration of CXCR3 than those in labor at term regardless of the presence or absence of placental lesions. CONCLUSION: Our findings support a role for maternal anti-fetal rejection in a subset of patients with preterm labor.

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

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

Preterm labor in the absence of acute histologic chorioamnionitis is characterized by cellular senescence of the chorioamniotic membranes.

BACKGROUND: Decidual senescence has been considered a mechanism of disease for spontaneous preterm labor in the absence of severe acute inflammation. Yet, signs of cellular senescence have also been observed in the chorioamniotic membranes from women who underwent the physiological process of labor at term. OBJECTIVE: We aimed to investigate whether, in the absence of acute histologic chorioamnionitis, the chorioamniotic membranes from women who underwent spontaneous preterm labor or labor at term exhibit signs of cellular senescence. STUDY DESIGN: Chorioamniotic membrane samples were collected from women who underwent spontaneous preterm labor or labor at term. Gestational age-matched nonlabor controls were also included. Senescence-associated genes/proteins were determined using reverse transcription quantitative polymerase chain reaction analysis (n = 7-9 each for array; n = 26-28 each for validation), enzyme-linked immunosorbent assays (n = 7-9 each), immunoblotting (n = 6-7 each), and immunohistochemistry (n = 7-8 each). Senescence-associated ß-galactosidase activity (n = 7-11 each) and telomere length (n = 15-22 each) were also evaluated. RESULTS: In the chorioamniotic membranes without acute histologic chorioamnionitis: (1) the expression profile of senescence-associated genes was different between the labor groups (term in labor and preterm in labor) and the nonlabor groups (term no labor and preterm no labor), yet there were differences between the term in labor and preterm in labor groups; (2) most of the differentially expressed genes among the groups were closely related to the tumor suppressor protein (TP53) pathway; (3) the expression of TP53 was down-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (4) the expression of CDKN1A (gene coding for p21) was up-regulated in the term in labor and preterm in labor groups compared to their nonlabor counterparts; (5) the expression of the cyclin kinase CDK2 and cyclins CCNA2, CCNB1, and CCNE1 was down-regulated in the preterm in labor group compared to the preterm no labor group; (6) the concentration of TP53 was lower in the preterm in labor group than in the preterm no labor and term in labor groups; (7) the senescence-associated ß-galactosidase activity was greater in the preterm in labor group than in the preterm no labor and term in labor groups; (8) the concentration of phospho-S6 ribosomal protein was reduced in the term in labor group compared to its nonlabor counterpart, but no differences were observed between the preterm in labor and preterm no labor groups; and (9) no significant differences were observed in relative telomere length among the study groups (term no labor, term in labor, preterm no labor, and preterm in labor). CONCLUSION: In the absence of acute histologic chorioamnionitis, signs of cellular senescence are present in the chorioamniotic membranes from women who underwent spontaneous preterm labor compared to those who delivered preterm in the absence of labor. However, the chorioamniotic membranes from women who underwent spontaneous labor at term did not show consistent signs of cellular senescence in the absence of histologic chorioamnionitis. These results suggest that different pathways are implicated in the pathological and physiological processes of labor.

Metformin, the aspirin of the 21st century: its role in gestational diabetes mellitus, prevention of preeclampsia and cancer, and the promotion of longevity.

Metformin is everywhere. Originally introduced in clinical practice as an antidiabetic agent, its role as a therapeutic agent is expanding to include treatment of prediabetes mellitus, gestational diabetes mellitus, and polycystic ovarian disease; more recently, experimental studies and observations in randomized clinical trials suggest that metformin could have a place in the treatment or prevention of preeclampsia. This article provides a brief overview of the history of metformin in the treatment of diabetes mellitus and reviews the results of metaanalyses of metformin in gestational diabetes mellitus as well as the treatment of obese, non-diabetic, pregnant women to prevent macrosomia. We highlight the results of a randomized clinical trial in which metformin administration in early pregnancy did not reduce the frequency of large-for-gestational-age infants (the primary endpoint) but did decrease the frequency of preeclampsia (a secondary endpoint). The mechanisms by which metformin may prevent preeclampsia include a reduction in the production of antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 and soluble endoglin) and the improvement of endothelial dysfunction, probably through an effect on the mitochondria. Another potential mechanism whereby metformin may play a role in the prevention of preeclampsia is its ability to modify cellular homeostasis and energy disposition, mediated by rapamycin, a mechanistic target. Metformin has a molecular weight of 129 Daltons and therefore readily crosses the placenta. There is considerable evidence to suggest that this agent is safe during pregnancy. New literature on the role of metformin as a chemotherapeutic adjuvant in the prevention of cancer and in prolonging life and protecting against aging is reviewed briefly. Herein, we discuss the mechanisms of action and potential benefits of metformin.

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

BACKGROUND: Recent studies on clinical chorioamnionitis at term suggest that some patients with this diagnosis have neither intraamniotic infection nor intraamniotic inflammation. A false-positive diagnosis of clinical chorioamnionitis in preterm gestation may lead to unwarranted preterm delivery. OBJECTIVE: We sought to determine the frequency of intraamniotic inflammation and microbiologically proven amniotic fluid infection in patients with preterm clinical chorioamnionitis. STUDY DESIGN: Amniocentesis was performed in singleton pregnant women with preterm clinical chorioamnionitis (<36 weeks of gestation). Amniotic fluid was cultured for aerobic and anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8 concentration. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture; intraamniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration of >23 ng/mL. Nonparametric and survival techniques were used for analysis. RESULTS: Among patients with preterm clinical chorioamnionitis, 24% (12/50) had neither microbiologic evidence of intraamniotic infection nor intraamniotic inflammation. Microbial invasion of the amniotic cavity was present in 34% (18/53) and intraamniotic inflammation in 76% (38/50) of patients. The most common microorganisms isolated from the amniotic cavity were the Ureaplasma species. Finally, patients without microbial invasion of the amniotic cavity or intraamniotic inflammation had significantly lower rates of adverse outcomes (including lower gestational age at delivery, a shorter amniocentesis-to-delivery interval, acute histologic chorioamnionitis, acute funisitis, and significant neonatal morbidity) than those with microbial invasion of the amniotic cavity and/or intraamniotic inflammation. CONCLUSION: Among patients with preterm clinical chorioamnionitis, 24% had no evidence of either intraamniotic infection or intraamniotic inflammation, and 66% had negative amniotic fluid cultures, using standard microbiologic techniques. These observations call for a reexamination of the criteria used to diagnose preterm clinical chorioamnionitis.