Role of Platelet Activating Factor as a Mediator of Inflammatory Diseases and Preterm Delivery.

Nearly 70% of preterm deliveries occur spontaneously, and the clinical pathways involved include preterm labor and preterm premature rupture of membranes. Prediction of preterm delivery is considered crucial due to the significant effects of preterm birth on health and the economy at both the personal and community levels. Although similar inflammatory processes occur in both term and preterm delivery, the premature activation of these processes or exaggerated inflammatory response triggered by infection or sterile factors leads to preterm delivery. Platelet activating factor (PAF) is a phosphoglycerylether lipid mediator of inflammation that is implicated in infections, cancers, and various chronic diseases and disorders including cardiovascular, renal, cerebrovascular, and central nervous system diseases. In gestational tissues, PAF mediates the inflammatory pathways that stimulate the effector mechanisms of labor, including myometrial contraction, cervical dilation, and fetal membrane rupture. Women with preterm labor and preterm premature rupture of membranes have increased levels of PAF in their amniotic fluid. In mice, the intrauterine or intraperitoneal administration of carbamyl PAF activates inflammation in gestational tissues, thereby eliciting preterm delivery. This review summarizes recent research on PAF as an important inflammatory mediator in preterm delivery and in other inflammatory disorders, highlighting its potential value for prediction, intervention, and prevention of these diseases.

Regulation of 20α-Hydroxysteroid Dehydrogenase Expression in Term Pregnant Human Myometrium Ex Vivo.

Metabolic inactivation of progesterone within uterine myocytes by 20α-hydroxysteroid dehydrogenase (20α-HSD) has been postulated as a mechanism contributing to functional progesterone withdrawal at term. In humans, 20α-HSD is encoded by the gene AKR1C1. Myometrial AKR1C1 mRNA abundance has been reported to increase significantly during labor at term. In spontaneous preterm labor, however, we previously found no increase in AKR1C1 mRNA level in the myometrium except for preterm labor associated with clinical chorioamnionitis. This suggests that increased 20α-HSD activity is a mechanism through which inflammation drives progesterone withdrawal in preterm labor. In this study, we have determined the effects of various treatments of therapeutic relevance on AKR1C1 expression in pregnant human myometrium in an ex vivo culture system. AKR1C1 expression increased spontaneously during 48 h culture (p < 0.0001), consistent with the myometrium transitioning to a labor-like phenotype ex vivo, as reported previously. Serum supplementation, prostaglandin F2α, phorbol myristate acetate, and mechanical stretch had no effect on the culture-induced increase, whereas progesterone (p = 0.0058) and cAMP (p = 0.0202) further upregulated AKR1C1 expression. In contrast, culture-induced upregulation of AKR1C1 expression was dose-dependently repressed by three histone/protein deacetylase inhibitors: trichostatin A at 5 (p = 0.0172) and 25 µM (p = 0.0115); suberoylanilide hydroxamic acid at 0.5 (p = 0.0070), 1 (p = 0.0045), 2.5 (p = 0.0181), 5 (p = 0.0066) and 25 µM (p = 0.0014); and suberoyl bis-hydroxamic acid at 5 (p = 0.0480) and 25 µM (p = 0.0238). We propose the inhibition of histone/protein deacetylation helps to maintain the anti-inflammatory, pro-quiescence signaling of progesterone in pregnant human myometrium by blocking its metabolic inactivation. Histone deacetylase inhibitors may represent a class of agents that preserve or restore the progesterone sensitivity of the pregnant uterus.

ß3 Receptor Signaling in Pregnant Human Myometrium Suggests a Role for ß3 Agonists as Tocolytics.

Preterm labor leading to preterm birth is the leading cause of infant morbidity and mortality. At the present time, nothing can reliably halt labor once it begins. The knowledge that agonists of the ß2 adrenergic receptor relax airway smooth muscle and are effective in the treatment of asthma led to the notion that ß2 mimetics would prevent preterm birth by relaxing uterine smooth muscle. The activation of cAMP-dependent protein kinase by ß2 receptors is unable to provide meaningful tocolysis. The failure of ß2 agonists such as ritodrine and terbutaline to prevent preterm birth suggests that the regulation of uterine smooth muscle is disparate from that of airway. Other smooth muscle quiescent-mediating molecules, such as nitric oxide, relax vascular smooth muscle in a cGMP-protein kinase G-dependent manner; however, nitric oxide activation of protein kinase G fails to explain the relaxation of the myometrium to nitric oxide. Moreover, nitric oxide-mediated relaxation is blunted in preterm labor, and thus, for this reason and because of the fall in maternal blood pressure, nitric oxide cannot be employed as a tocolytic. The ß3 adrenergic receptor-mediated relaxation of the human myometrium is claimed to be cAMP-dependent protein kinase-dependent. This is scientifically displeasing given the failure of ß2 agonists as tocolytics and suggests a non-canonical signaling role for ß3AR in myometrium. The addition of the ß3 agonist mirabegron to pregnant human myometrial strips in the tissue bath relaxes oxytocin-induced contractions. Mirabegron stimulates nitric oxide production in myometrial microvascular endothelial cells, and the relaxation of uterine tissue in vitro is partially blocked by the addition of the endothelial nitric oxide synthase blocker Nω-Nitro-L-arginine. Recent data suggest that both endothelial and smooth muscle cells respond to ß3 stimulation and contribute to relaxation through disparate signaling pathways. The repurposing of approved medications such as mirabegron (Mybetriq™) tested in human myometrium as uterine tocolytics can advance the prevention of preterm birth.

Circulating Extracellular Vesicles microRNAs Are Altered in Women Undergoing Preterm Birth.

Preterm labor (PTL) and preterm premature rupture of membranes (PPROM) lead to high perinatal morbidity/mortality rates worldwide. Small extracellular vesicles (sEV) act in cell communication and contain microRNAs that may contribute to the pathogenesis of these complications. We aimed to compare the expression, in sEV from peripheral blood, of miRNAs between term and preterm pregnancies. This cross-sectional study included women who underwent PTL, PPROM, and term pregnancies, examined at the Botucatu Medical School Hospital, SP, Brazil. sEV were isolated from plasma. Western blot used to detect exosomal protein CD63 and nanoparticle tracking analysis were performed. The expression of 800 miRNAs was assessed by the nCounter Humanv3 miRNA Assay (NanoString). The miRNA expression and relative risk were determined. Samples from 31 women-15 preterm and 16 term-were included. miR-612 expression was increased in the preterm groups. miR-612 has been shown to increase apoptosis in tumor cells and to regulate the nuclear factor κB inflammatory pathway, processes involved in PTL/PPROM pathogenesis. miR-1253, miR-1283, miR378e, and miR-579-3p, all associated with cellular senescence, were downregulated in PPROM compared with term pregnancies. We conclude that miRNAs from circulating sEV are differentially expressed between term and preterm pregnancies and modulate genes in pathways that are relevant to PTL/PPROM pathogenesis.

Evidence for the participation of CHCHD2/MNRR1, a mitochondrial protein, in spontaneous labor at term and in preterm labor with intra-amniotic infection.

OBJECTIVE: Intra-amniotic inflammation (IAI), associated with either microbe (infection) or danger signals (sterile), plays a major role in the pathophysiology of preterm labor and delivery. Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 2 (CHCHD2) [also known as Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1)], a mitochondrial protein involved in oxidative phosphorylation and cell survival, is capable of sensing tissue hypoxia and inflammatory signaling. The ability to maintain an appropriate energy balance at the cellular level while adapting to environmental stress is essential for the survival of an organism. Mitochondrial dysfunction has been observed in acute systemic inflammatory conditions, such as sepsis, and is proposed to be involved in sepsis-induced multi-organ failure. The purpose of this study was to determine the amniotic fluid concentrations of CHCHD2/MNRR1 in pregnant women, women at term in labor, and those in preterm labor (PTL) with and without IAI. METHODS: This cross-sectional study comprised patients allocated to the following groups: (1) mid-trimester (n = 16); (2) term in labor (n = 37); (3) term not in labor (n = 22); (4) PTL without IAI who delivered at term (n = 25); (5) PTL without IAI who delivered preterm (n = 47); and (6) PTL with IAI who delivered preterm (n = 53). Diagnosis of IAI (amniotic fluid interleukin-6 concentration ≥2.6 ng/mL) included cases associated with microbial invasion of the amniotic cavity and those of sterile nature (absence of detectable bacteria, using culture and molecular microbiology techniques). Amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations were determined with a validated and sensitive immunoassay. RESULTS: (1) CHCHD2/MNRR1 was detectable in all amniotic fluid samples and women at term without labor had a higher amniotic fluid CHCHD2/MNRR1 concentration than those in the mid-trimester (p = 0.003); (2) the amniotic fluid concentration of CHCHD2/MNRR1 in women at term in labor was higher than that in women at term without labor (p = 0.01); (3) women with PTL and IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those without IAI, either with preterm (p < 0.001) or term delivery (p = 0.01); (4) women with microbial-associated IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those with sterile IAI (p < 0.001); (5) among women with PTL and IAI, the amniotic fluid concentration of CHCHD2/MNRR1 correlated with that of interleukin-6 (Spearman's Rho = 0.7; p < 0.001); and (6) no correlation was observed between amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations among women with PTL. CONCLUSION: CHCHD2/MNRR1 is a physiological constituent of human amniotic fluid in normal pregnancy, and the amniotic concentration of this mitochondrial protein increases during pregnancy, labor at term, and preterm labor with intra-amniotic infection. Hence, CHCHD2/MNRR1 may be released into the amniotic cavity by dysfunctional mitochondria during microbial-associated IAI.

20α-Hydroxysteroid Dehydrogenase Expression in the Human Myometrium at Term and Preterm Birth: Relationships to Fetal Sex and Maternal Body Mass Index.

The mechanism by which human labor is initiated in the presence of elevated circulating progesterone levels remains unknown. Recent evidence indicates that the progesterone-metabolizing enzyme, 20α-hydroxysteroid dehydrogenase (20α-HSD), encoded by the gene AKR1C1, may contribute to functional progesterone withdrawal. We found that AKR1C1 expression significantly increased with labor onset in term myometrium, but not in preterm myometrium. Among preterm laboring deliveries, clinically diagnosed chorioamnionitis was associated with significantly elevated AKR1C1 expression. AKR1C1 expression positively correlated with BMI before labor and negatively correlated with BMI during labor. Analysis by fetal sex showed that AKR1C1 expression was significantly higher in women who delivered male babies compared to women who delivered female babies at term, but not preterm. Further, in pregnancies where the fetus was female, AKR1C1 expression positively correlated with the mother's age and BMI at the time of delivery. In conclusion, the increase in myometrial AKR1C1 expression with term labor is consistent with 20α-HSD playing a role in local progesterone metabolism to promote birth. Interestingly, this role appears to be specific to term pregnancies where the fetus is male. Upregulated AKR1C1 expression in the myometrium at preterm in-labor with clinical chorioamnionitis suggests that increased 20α-HSD activity is a mechanism through which inflammation drives progesterone withdrawal in preterm labor. The link between AKR1C1 expression and maternal BMI may provide insight into why maternal obesity is often associated with dysfunctional labor. Higher myometrial AKR1C1 expression in male pregnancies may indicate fetal sex-related differences in the mechanisms that precipitate labor onset at term.

NETs promote ROS production to induce human amniotic epithelial cell apoptosis via ERK1/2 signaling in spontaneous preterm birth.

PROBLEM: Premature birth is a common obstetric complication but its pathogenesis is unclear. Inflammation at the maternal-fetal interface in preterm labor leads to the infiltration of neutrophils, which promotes inflammatory responses and induces the degradation of extracellular matrix and cell apoptosis, thus contributing to preterm labor. It is unclear whether neutrophil extracellular traps (NETs), a functional form of neutrophils, are involved in preterm labor. METHODS OF STUDY: After collecting amniotic membranes from research objects, we localized NETs by immunofluorescence and evaluated the expression of matrix metalloproteinase (MMP)-9 and MMP-2 by western blotting. Primary human amniotic epithelial cells (hAECs) subjected to treatment with NETs, 5-ethynyl-20-deoxyuridine cell proliferation assay, lactate dehydrogenase (LDH) assay, western blotting, and flow cytometry apoptosis assay were used to determine the effects of NETs on hAECs. We also elucidated possible mechanisms underlying the effects. RESULTS: Compared with normal term women, NETs infiltration and MMP-9 expression in the amniotic membrane from preterm women had increased. Thereafter, NETs might suppress the proliferation and promote the apoptosis of hAECs. Furthermore, after NETs treatment, the mitochondrial membrane potential was significantly decreased, ERK1/2 phosphorylation expression was upregulated and reactive oxygen species (ROS) production was increased in hAECs. Changes in cell proliferation, LDH release, and cell apoptosis level due to NETs could be reversed by ROS inhibitor or ERK phosphorylation inhibitors. CONCLUSIONS: NETs can promote the apoptosis of hAECs via ERK1/2 pathways dependent on ROS release.

MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL FEATURES OF PLACENTAL DAMAGE DUE TO THE INCORPORATION OF 137Cs. / MORFOLOGIChNI TA IMUNO-GISTOKhIMIChNI OSOBLYVOSTI POShKODZhENNIa PLATsENTY VNASLIDOK INKORPORUVANNIa 137Cs.

OBJECTIVE: to investigate the morphological and immunohistochemical features of placental damage due to theincorporation of 137Cs depending on the scenario of pregnancy completion. MATERIALS AND METHODS: The study material consisted of placentas from 60 women with reproductive losses inanamnesis and signs of termination of the current pregnancy (first group) and placental samples from 30 women with an uncomplicated gestation and an unencumbered anamnesis (control group). The detailed study required the distribution of placental samples from the first group into subgroups. Subgroup 1a included 38 placentas from women who gave birth at 37-40 weeks, despite signs of termination of the current pregnancy. Subgroup 1b - placentas of 13 women who gave birth at a gestation period of 28-36 weeks + 6 days. Subgroup 1c - 9 placental samples from women who gave birth at a gestation period of 22-27 weeks + 6 days. The volumetric activity of the 137Cs in the placentas was measured using ß-spectrometer. The histology of the placenta was studied using a standard technique. The following expressions were studied in placenta: CD31 / PECAM-1, CD45 / T200 / LCA, CD56 / NCAM-1, CEA / CD66e Ab-2, Vimentin, using indirect streptavidin peroxidase detection method. RESULTS: Placentas accumulate 137Cs. The different volumetric activity of the isotope correlates with scenarios of pregnancy. Due to the action of incorporated 137Cs with a specific mass of more than 1.1 Bq/kg, placental dysfunction develops. The consequences of placental dysfunction depend on the volumetric activity of the 137Cs and the preservation of adaptive and compensatory reactions in the placenta. Morphological and immunohistochemical features of placental damage to incorporated 137Cs were established, depending on the scenario of completion of pregnancy. A marker of unfavorable completion of pregnancy is the expression of a carcinoembryonic antigen (CEA) in the placenta. CONCLUSIONS: Premature termination of pregnancy (PTP) is a multifactorial pathology associated with pathological changes in immune and neuroendocrine regulation and hereditary, infectious, and environmental factors that disrupt the adaptation mechanisms in the mother-placenta-fetus system. Intraplacental irradiation of 137Cs is one of the factors in the multifactorial nature of reproductive losses. As a result of intraplacental irradiation of 137Cs, the architecture of the placenta is disturbed, the activity of pro-inflammatory cytokines CD45 and CD56 increases, and the coagulation cascade is activated. Extreme effects depend on the volumetric activity of the isotope incorporated in the placenta and the organ's compensatory capacity. Accumulation of up to 1.0 Bq/kg 137Cs does not affect the course of gestation. Internal irradiation with an activity of 4.5-10.4 Bq/kg 137Cs triggers late preterm labor. The nature of the damages corresponds to the category of «lesion of the maternal stroma¼ of the placenta. The volumetric activity of 137Cs over 10.4 Bq/kg is a probable cause of early preterm labor and antenatal fetal death. At the same time, the maternal and fetal structures of the placenta suffer damage. Expression of vimentin is a marker of placental destruction due to internal irradiation of 137Cs with a specific gravity of more than 4.5 Bq/kg. Expression of CEA in the structures of the placenta of women with PTP is a unique find and marker of premature birth and antenatal fetal death with intraplacental irradiation of 137Cs with an activity of more than 4.5 Bq/kg.

Inflammatory Proteins in the Amniotic Fluid, Plasma, and Cervicovaginal Fluid for the Prediction of Intra-Amniotic Infection/Inflammation and Imminent Preterm Birth in Preterm Labor.

OBJECTIVE: This study was aimed to develop models using multiple cytokine/chemokine levels in cervicovaginal fluid (CVF) and plasma and widely used noninvasive parameters that have better accuracy for predicting intra-amniotic infection and/or inflammation (IAI) and imminent spontaneous preterm delivery (SPTD, ≤48 hours) in women with preterm labor (PTL). STUDY DESIGN: This was a retrospective cohort study of 95 singleton pregnant women with PTL (23-34 weeks) who underwent amniocentesis. Both CVF and plasma samples were obtained at the time of amniocentesis, and serum C-reactive protein (CRP) levels were measured. The amniotic fluid (AF), CVF, and plasma samples were assayed for interleukin (IL)-6, IL-8, IL-10, monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1ß (MIP-1ß) levels using a multiplex immunoassay kit. RESULTS: The levels of most cytokines/chemokines measured in the AF and CVF were significantly higher in the women with than in those without IAI and imminent SPTD, whereas only high-plasma IL-10 level showed a significant association with imminent SPTD. In predicting IAI, proteins in AF had significantly higher areas under the curves (AUCs) than those in CVF and plasma. However, for predicting imminent SPTD, no significant differences in the AUCs of the outcome-associated proteins were observed among the measurements in AF, CVF, and maternal plasma. By using stepwise regression analyses, noninvasive models (using protein levels in CVF and baseline clinical parameters) were developed for the prediction of IAI and imminent SPTD. The AUC of these noninvasive models were similar to those of the invasive models (using AF protein levels and baseline clinical parameters). CONCLUSION: Noninvasive models based on CVF cytokine/chemokine levels and widely used noninvasive parameters (especially CRP) act as good indicators for predicting the risk of IAI and imminent SPTD in women with PTL. Evaluation of cytokine/chemokine levels in plasma samples did not add valuable information regarding the two outcome measures in the PTL setting. KEY POINTS: · Markers in either CVF or plasma alone did not have sufficient accuracy for predicting IAI and SPTD.. · Noninvasive models using CVF cytokine and CRP act as effective tools for predicting two outcomes.. · Evaluation of cytokine level in plasma did not add valuable information regarding two outcomes..

Macrophage inflammatory protein-1α in amniotic and cervical fluids in spontaneous preterm labor with intact membranes with respect to intra-amniotic inflammation.

OBJECTIVE: Macrophage inflammatory protein 1α is a chemokine produced by various immune, epithelial, mesothelial, and fibroblast cells after exposure to bacterial lipopolysaccharide or pro-inflammatory molecules. The primary aim of this study was to determine MIP-1α concentrations in amniotic and cervical fluids from pregnancy with spontaneous preterm labor with intact membranes (PTL) with respect to the presence of intra-amniotic infection (both microbial invasion of the amniotic cavity and intra-amniotic inflammation) and sterile intra-amniotic inflammation (intra-amniotic inflammation alone). The secondary aim was to assess the diagnostic indices of MIP-1α in predicting intra-amniotic infection. MATERIALS AND METHODS: Seventy-four women with PTL were included in this study. Paired amniotic and cervical fluid samples were obtained using transabdominal amniocentesis and a Dacron polyester swab, respectively. Microbial invasion of the amniotic cavity was diagnosed based on a combination of culture and molecular biology methods. The concentration of IL-6 in the amniotic and cervical fluids was measured using an automated electrochemiluminescence immunoassay method. Intra-amniotic inflammation was defined as an amniotic fluid IL-6 concentration of ≥3000 pg/mL. The MIP-1α concentrations in the samples were assessed using an enzyme-linked immunosorbent assay. RESULTS: A difference in amniotic fluid MIP-1α was observed among women with intra-amniotic infection, sterile intra-amniotic inflammation, and negative amniotic fluid (infection: median 1779.0 pg/mL; sterile, median 102.7 pg/mL; negative, median 19.9 pg/mL; p < .0001). No difference in the concentrations of MIP-1α was identified in cervical fluid after adjustment for gestational age at sampling (infection: median 77.7 pg/mL, sterile: median 152.7 pg/mL, negative: median 18.0 pg/mL; p = .30). The presence of intra-amniotic infection was associated with elevated MIP-1α concentrations in amniotic fluid (presence: 1779.0 pg/mL vs. absence: 26.3 pg/mL, p < .0001, area under receiver operating characteristic curve = 0.87). CONCLUSIONS: In PTL pregnancies with the presence of intra-amniotic infection, the concentration of MIP-1α is elevated in amniotic fluid but not in cervical fluid. Amniotic fluid MIP-1α may provide a useful marker for intra-amniotic infection in women with PTL.

Macrophages exert homeostatic actions in pregnancy to protect against preterm birth and fetal inflammatory injury.

Macrophages are commonly thought to contribute to the pathophysiology of preterm labor by amplifying inflammation - but a protective role has not previously been considered to our knowledge. We hypothesized that given their antiinflammatory capability in early pregnancy, macrophages exert essential roles in maintenance of late gestation and that insufficient macrophages may predispose individuals to spontaneous preterm labor and adverse neonatal outcomes. Here, we showed that women with spontaneous preterm birth had reduced CD209+CD206+ expression in alternatively activated CD45+CD14+ICAM3- macrophages and increased TNF expression in proinflammatory CD45+CD14+CD80+HLA-DR+ macrophages in the uterine decidua at the materno-fetal interface. In Cd11bDTR/DTR mice, depletion of maternal CD11b+ myeloid cells caused preterm birth, neonatal death, and postnatal growth impairment, accompanied by uterine cytokine and leukocyte changes indicative of a proinflammatory response, while adoptive transfer of WT macrophages prevented preterm birth and partially rescued neonatal loss. In a model of intra-amniotic inflammation-induced preterm birth, macrophages polarized in vitro to an M2 phenotype showed superior capacity over nonpolarized macrophages to reduce uterine and fetal inflammation, prevent preterm birth, and improve neonatal survival. We conclude that macrophages exert a critical homeostatic regulatory role in late gestation and are implicated as a determinant of susceptibility to spontaneous preterm birth and fetal inflammatory injury.

Molecular signatures of labor and nonlabor myometrium with parsimonious classification from 2 calcium transporter genes.

Clinical phenotyping of term and preterm labor is imprecise, and disagreement persists on categorization relative to underlying pathobiology, which remains poorly understood. We performed RNA sequencing (RNA-seq) of 31 specimens of human uterine myometrium from 10 term and 21 preterm cesarean deliveries with rich clinical context information. A molecular signature of 4814 transcripts stratified myometrial samples into quiescent (Q) and nonquiescent (NQ) phenotypes, independent of gestational age and incision site. Similar stratifications were achieved using expressed genes in Ca2+ signaling and TGF-ß pathways. For maximal parsimony, we evaluated the expression of just 2 Ca2+ transporter genes, ATP2B4 (encoding PMCA4) and ATP2A2 (coding for SERCA2), and we found that their ratio reliably distinguished NQ and Q specimens in the current study, and also in 2 publicly available RNA-seq data sets (GSE50599 and GSE80172), with an overall AUC of 0.94. Cross-validation of the ATP2B4/ATP2A2 ratio by quantitative PCR in an expanded cohort (by 11 additional specimens) achieved complete separation (AUC of 1.00) of NQ versus Q specimens. While providing additional insight into the associations between clinical features of term and preterm labor and myometrial gene expression, our study also offers a practical algorithm for unbiased classification of myometrial biopsies by their overall contractile program.

Uric acid participating in female reproductive disorders: a review.

Uric acid (UA) is the end metabolic product of purine metabolism. Early on, UA was considered to be a metabolite with a certain antioxidant capacity. As research has progressed, other properties of UA have been explored, and its association with many diseases has been found. The association between UA and kidney disease and cardiovascular disease is well established; however, there is still a paucity of reviews on the association between UA and the female reproductive system. An increasing number of epidemiological studies have shown elevated serum UA levels in patients with polycystic ovary syndrome (PCOS), endometriosis, etc. Additionally, serum UA can be used as a predictor of pregnancy complications and adverse foetal outcomes. An increasing number of animal experiments and clinical studies have revealed possible mechanisms related to the involvement of UA in certain female reproductive disorders: oxidative stress, chronic inflammation, mitochondrial dysfunction, etc. This article reviews the current mainstream mechanisms regarding the pathogenesis of UA and the role of UA in certain specific female reproductive disorders (direct involvement in the development of certain diseases or enhancement of other risk factors) in the hope of contributing to clinical prevention, diagnosis, treatment and improvement in prognosis.

Methods of detection and prevention of preterm labour and the PAMG-1 detection test: a review.

OBJECTIVES: Preterm labour is the leading cause of hospitalization during pregnancy. In France, it results in more than 60,000 births before 37 weeks of gestation every year. Recent studies suggest that detection of placental α-microglobulin-1 (PAMG-1) in vaginal secretions among women presenting symptoms of preterm labour with intact membranes has good predictive value for the onset of spontaneous preterm delivery within 7 days. The test is especially interesting, in that the repetition of antenatal corticosteroids for foetal lung maturation is no longer recommended in France and the effect of the initial administration is most beneficial in the 24 h to 7 days afterwards. METHODS: We included all studies listed in PubMed and clinicaltrials.gov with the terms "PAMG-1" and either "preterm labor" or "preterm labour", while excluding all studies on the subject of "rupture of the membranes" from 2000 through 2017. Ten studies were thus included. RESULTS: In women who had both the PAMG-1 and foetal fibronectin test, the PAMG-1 test was statistically superior to the measurement of cervical length for positive predictive value (p<0.0074), negative predictive value (p=0.0169) and specificity (p<0.001) for the prediction of spontaneous preterm delivery within 7 days. CONCLUSIONS: The use of PAMG-1 may make it possible to target the women at risk with a shortened cervix on ultrasound (<25 mm) those with an imminent preterm delivery and therefore to adapt management, especially the administration of antenatal corticosteroid therapy.

Antibody microarray analysis of amniotic fluid proteins associated with subsequent ruptured membranes in women with threatened preterm labor.

PROBLEM: We aimed to identify amniotic fluid (AF) proteins associated with the subsequent rupture of membranes (ROM) occurring in the absence of active labor in women with threatened preterm labor (PTL) using an antibody microarray. METHOD OF THE STUDY: This retrospective cohort study included 183 singleton pregnant women with PTL (24-33 weeks) who underwent amniocentesis. A nested case-control study was conducted using AF samples from 20 women with subsequent ROM within 7 days of sampling (case subjects) and 20 gestational age-matched women with term delivery (TD) without ROM (control subjects), via protein-antibody microarray analysis. Seven candidate proteins of interest were validated via ELISA in the total cohort. RESULTS: Seventeen proteins displayed significant intergroup differences. ELISA validation confirmed that the levels of EN-RAGE, Fas, IL-8, IP-10, MMP-8, and MMP-9 were significantly higher, whereas IGFBP-3 levels were significantly lower in the AF of women with subsequent ROM within 7 days of sampling than in that of women with TD without ROM. Moreover, the time interval from sampling to membrane rupture was significantly correlated with the expression levels of AF proteins, except for IL-10. CONCLUSION: Using an antibody microarray, we identified various inflammatory, angiogenic, matrix-degrading, and apoptosis-related proteins in the AF that were associated with subsequent ROM occurring in the absence of active labor in women with threatened PTL. These findings provide novel insights into the molecular mechanisms underlying membrane rupture without active labor in threatened PTL.

A protein microarray analysis of amniotic fluid proteins for the prediction of spontaneous preterm delivery in women with preterm premature rupture of membranes at 23 to 30 weeks of gestation.

OBJECTIVE: We sought to identify novel biomarkers in the amniotic fluid (AF) related to imminent spontaneous preterm delivery (SPTD) (≤ 14 days after sampling) in women with early preterm premature rupture of membranes (PPROM), using a protein microarray. METHOD: This was a retrospective cohort study of a total of 88 singleton pregnant women with PPROM (23+0 to 30+6 weeks) who underwent amniocentesis. A nested case-control study for biomarker discovery was conducted using pooled AF samples from controls (non-imminent delivery, n = 15) and cases (imminent SPTD, n = 15), which were analyzed using an antibody microarray. Quantitative validation of four candidate proteins was performed, using ELISA, in the total cohort (n = 88). IL-8, MMP-9, and Fas levels were additionally measured for the comparison and to examine association of SPTD with the etiologic factors of PPROM. RESULTS: Of all the proteins studied in the protein microarray, four showed significant intergroup differences. Analyses of the total cohort by ELISA confirmed the significantly elevated concentrations of AF lipocalin-2, MMP-9, and S100 A8/A9, but not of endostatin and Fas, in women who delivered within 14 days of sampling. For inflammatory proteins showing a significant association, the odds of SPTD within 14 days increased significantly with an increase in baseline AF levels of the proteins (P for trend <0.05 for each) in each quartile, especially in the 3rd and 4th quartile. CONCLUSIONS: We identified several potential novel biomarkers (i.e., lipocalin-2, MMP-9, and S100 A8/A9) related to SPTD within 14 days of sampling, all of which are inflammation-related molecules. Furthermore, the SPTD risk increased with increasing quartiles of each of these inflammatory proteins, especially the 3rd and 4th quartile of each protein. The present findings may highlight the importance of inflammatory mechanisms and the degree of activated inflammatory response in developing SPTD in early PPROM.

Changes in cAMP effector predominance are associated with increased oxytocin receptor expression in twin but not infection-associated or idiopathic preterm labour.

We previously reported that at term pregnancy, a decline in myometrial protein kinase A (PKA) activity leads to an exchange protein activated by cyclic AMP (Epac1)-dependent increase in oxytocin receptor (OTR) expression, promoting the onset of labour. Here, we studied the changes in the cyclic adenosine monophosphate (cAMP) effector system present in different phenotypes of preterm labour (PTL). Myometrial biopsies obtained from women with phenotypically distinct forms of PTL and the levels of PKA and OTR were examined. Although we found similar changes in the cAMP effector pathway in all forms of PTL, only in the case of twin PTL (T-PTL) was myometrial OTR levels increased in association with these results. Although there were several changes in the mRNA levels of components of the cAMP synthetic pathway, the total myometrial cAMP levels did not change with the onset of any subtype of PTL. With regards to the expression of cAMP-responsive genes, we found that the mRNA levels of 4 of the 5 cAMP-down-regulated genes were increased in T-PTL, similar to our findings in term labour. These data signify that although changes in the cAMP effector system were common to all forms of PTL, only in T-PTL were OTR levels increased. Similarly, the mRNA levels of cAMP-repressed genes were only increased in T-PTL supporting the concept that the decline in PKA levels influences myometrial function driving the onset of T-PTL.

Identifying potential biomarkers related to pre-term delivery by proteomic analysis of amniotic fluid.

We sought to identify biomarkers in the amniotic fluid (AF) and specific signaling pathways related to spontaneous preterm delivery (SPTD, < 34 weeks) in women with preterm labor (PTL) without intra-uterine infection/inflammation (IUI). This was a retrospective cohort study of a total of 139 PTL women with singleton gestation (24 + 0 to 32 + 6 weeks) who underwent amniocentesis and who displayed no evidence of IUI. A nested case-control was conducted using pooled AF samples (n = 20) analyzed via label-free liquid chromatography-tandem mass spectrometry. In the total cohort, an ELISA validation study was performed for seven candidate proteins of interest. Proteomic analysis identified 77 differentially expressed proteins (DEPs, P < 0.05) in the AF from SPTD cases compared to term delivery controls. ELISA validation confirmed that women who had an SPTD before 34 weeks had significantly independently lower levels of VEGFR-1 and higher levels of lipocalin-2 and the Fc fragment of IgG binding protein in the AF. Five principle pathways associated with the 77 DEPs were identified, including glycolysis, gluconeogenesis, and iron homeostasis. The proteomic analysis data of AFs from women with PTL identified several novel biomarkers and specific protein pathways related to SPTD in the absence of IUI.

Neuromedin B receptor mediates neuromedin B-induced COX-2 and IL-6 expression in human primary myometrial cells.

The precise mechanisms that lead to parturition remain unclear. In our initial complementary DNA (cDNA) microarray experiment, we found that the neuromedin B receptor (NMBR) was differentially expressed in the human myometrium during spontaneous or oxytocin-induced labor. We have previously shown that neuromedin B (NMB) could induce interleukin 6 (IL-6) and type 2 cyclo-oxygenase enzyme (COX-2) expression in the primary human myometrial cells via nuclear factor kappa B (NF-κB) transcription factor p65 (p65) and Jun proto-oncogene, activator protein 1 (AP-1) transcription factor subunit (c-Jun). This study is aimed to investigate whether NMBR is required for NMB-induced effect. Primary myometrial cell culture was established to provide a suitable model to investigate the mechanism of NMB in labor initiation. Immunochemical staining was conducted to validate the NMBR expression in primary myometrial cells. The mRNA and protein expression of NMBR, p65, c-Jun, COX-2 and IL-6 were assessed by Quantitative Real Time PCR (RT-qPCR) and western blotting. Lentiviruses with shRNAs targeting NMBR or containing cDNA sequence of NMBR were transfected to primary myometrial cells to knockdown or overexpress NMBR. Cell death was determined by annexin V and propidium iodide staining and analyzed by flow cytometry. The upregulation of COX-2 and IL-6 and phosphorylation of p65 and c-Jun were significantly attenuated by knockdown of NMBR and enhanced by overexpressed NMBR following NMB treatment, with no significant change in total p65 and c-Jun. In summary, this study showed that NMBR-mediated NMB-induced NF-κB and AP-1 activation, which in turn, induce expression of IL-6 and COX-2 in primary myometrial cells.

Does Caesarean Section or Preterm Delivery Influence TGF-ß2 Concentrations in Human Colostrum?

Human colostrum (HC) is a rich source of immune mediators that play a role in immune defences of a newly born infant. The mediators include transforming growth factor ß (TGF-ß) which exists in three isoforms that regulate cellular homeostasis and inflammation, can induce or suppress immune responses, limit T helper 1 cells (Th1) reactions and stimulate secretory immunoglobulin A (IgA) production. Human milk TGF-ß also decreases apoptosis of intestinal cells and suppresses macrophage cytokine expression. The aim of the study was to determine the concentration of TGF-ß2 in HC obtained from the mothers who delivered vaginally (VD) or by caesarean section (CS), and to compare the concentrations in HC from mothers who delivered at term (TB) or preterm (PB). In this study, 56% of preterm pregnancies were delivered via CS. The concentrations of TGF-ß2 were measured in HC from 299 women who delivered in the 1st Department of Obstetrics and Gynaecology, Medical University of Warsaw: 192 (VD), 107 (CS), 251 (TB), and 48 (PB). The colostrum samples were collected within 5 days post-partum. TGF-ß2 levels in HC were measured by the enzyme-linked immunosorbent assay (ELISA) test with the Quantikine ELISA Kit-Human TGF-ß2 (cat.no. SB250). Statistical significance between groups was calculated by the Student t-test using StatSoft Statistica 13 software. The mean TGF-ß2 concentration in patients who delivered at term or preterm were comparable. The levels of TGF-ß2 in HC were higher after preterm than term being 4648 vs. 3899 ng/mL (p = 0.1244). The delivery via CS was associated with higher HC concentrations of TGF-ß2. The levels of TGF-ß2 were significantly higher in HC after CS than VD (7429 vs. 5240 ng/mL; p = 0.0017). The data from this study suggest: caesarean section was associated with increased levels of TGF-ß2 in HC. The increased levels of TGF-ß2 in HC of women who delivered prematurely require further research. Early and exclusive breast-feeding by mothers after caesarean section and premature births with colostrum containing high TGF-ß2 levels may prevent the negative impact of pathogens which often colonize the gastrointestinal tract and may reduce the risk of chronic diseases in this group of patients.