Identifying the potential protein biomarkers of preterm birth in amniotic fluid

ObjectivePreterm birth severely threatens neonatal health and life. Although the detailed mechanism of preterm birth is not well understood, accurately predicting preterm birth can help people make preparations in advance, greatly reducing the subsequent health risk of neonates. Therefore, in this study, we aimed to identify potential protein biomarkers of preterm birth in amniotic fluid (AF).Materials and methodsWe first enrolled pregnant subjects and collected their AF samples when they underwent amniocentesis at the second trimester of gestation. After delivery, the collected AF samples were classified into a full-term birth (sample size n = 21) set or preterm birth (n = 36) set, followed by 2-D DIGE and MS/MS assays.ResultsBy doing so, we identified seven potential protein biomarkers of preterm birth, three of which were further validated in all samples with ELISA, including Apolipoprotein A-IV (Apoa4), Lumican (Lum) and Kininogen-1 (Kng1). As a result, all three potential biomarkers were significantly differently expressed between preterm and full-term birth AF samples. Furthermore, without prior classification, we found that these three biomarkers were positively correlated with gestation age (correlation coefficient ranging from 0.25 to 0.38) and were able to predict the occurrence of preterm birth.ConclusionIn this study, by examining amniotic fluid, we identified three biomarker proteins that may facilitate the identification of preterm birth. There three proteins were never reported to be related to preterm birth. Their pathogenesis roles in preterm birth deserve further investigations by using in vitro cell model or in vivo animal model assays.     

Proteomic analysis of midtrimester amniotic fluid to identify novel biomarkers for preterm delivery

Objective: The aim of this study was to identify possible biomarkers for preterm delivery by analyzing midtrimester amniotic fluid. Methods: Thirty-two amniotic fluid samples were studied; 16 patients had a spontaneous preterm delivery and 16 patients delivered at term. The proteomic technique consisted of surface-enhanced laser desorption ionization time-of-flight (SELDI-TOF) using different types of solid chromatographic chips (Q10, CM10 and IMAC30). Results: Mass spectrometry tracings were obtained from the amniotic fluids of both patients who delivered preterm and patients who delivered at term. Seven potential markers were identified to be differentially expressed in patients who delivered preterm. Conclusions: Proteomic analysis of amniotic fluid obtained in the midtrimester reveals the presence of a set of proteins in patients at risk for preterm delivery.     

Maternal plasma and amniotic fluid dehydroepiandrosterone-sulfate concentrations in preterm labor and delivery

The purpose of this study was to determine whether preterm parturition is associated with changes in maternal plasma and amniotic fluid dehydroepiandrosterone-sulfate concentrations. A cross sectional study was constructed according to the gestational age at admission and response to tocolysis. Group 1 consisted of women admitted with preterm labor and intact membranes between 28 and 31 weeks and 6 days gestational age (n=40). Group 2 included 40 patients with preterm labor between 32 and 36 weeks gestational age. Both groups were classified into two subgroups: preterm delivery within seven days of admission and term delivery. Commercially available immunoassay kits validated for amniotic fluid analysis of DHEA-S, were used to measure maternal plasma and amniotic fluid DHEA-S concentrations. Maternal plasma DHEA-S concentrations were significantly higher in women with preterm labor who delivered preterm than in those who delivered at term. (Group 1: median 800 ng/ml [range 100–1100] vs. median 200 ng/ml [70–800],P<0.001; Group 2: median 850 ng/ml [300–1700] vs. median 300 ng/ml [90–1100],P<0.001). In contrast, no significant differences were detected in amniotic fluid DHEA-S concentrations. Our data suggest that the rise in maternal plasma DHEA-S concentrations observed in patients with preterm labor may be related to the effects of stress during labor.     

Amniotic fluid urocortin,CRF, oestriol,dehydroepiandrosterone sulfate and cortisol concentrations at mid-trimester: putative relationship with preterm delivery

Objective

Stress-related peptide and steroid hormones are involved in the pathogenesis of preterm delivery, even though their clinical usefulness as predictive markers of preterm delivery remains unclear. The present study evaluated whether mid-trimester amniotic fluid concentrations of stress-related peptides, that is corticothophin-releasing factor (CRF) and urocortin (Ucn) and feto-placental steroids (oestriol, DHEA-S and cortisol) correlated with preterm delivery.

Study design

It is a retrospective case–control study. Healthy women (n = 130) undergoing amniocentesis at mid-gestation for genetic indications, of whom 15 had a preterm delivery (cases) and 115 delivered at term (controls). CRF, urocortin, cortisol, DHEA-S and oestriol concentrations were measured by specific and sensitive immunoenzymatic assays.

Results

Amniotic fluid urocortin concentrations in the cases (0.50 ± 0.07 ng/ml) (M ± SD) were significantly lower (P < 0.0001) than in the control group (0.90 ± 0.26 ng/ml), while CRF concentrations did not differ between the cases (1.52 ± 0.39 ng/ml) and control group (1.64 ± 0.68 ng/ml). Amniotic fluid cortisol (17.71 ± 3.72 ng/ml vs. 17.32 ± 3.17 ng/ml), DHEA-S (0.16 ± 0.06 ng/ml vs. 0.17 ± 0.09 ng/ml) and oestriol (4.68 ± 1.95 ng/ml vs. 4.79 ± 1.84 ng/ml) concentrations were similar in the two groups.

Conclusions

The low amniotic fluid concentrations of urocortin at mid-trimester may be a signal of predisposition to preterm delivery, while the unchanged CRF and steroid hormones concentrations in women delivering preterm suggest that this mechanisms are not yet activated at mid-trimester.     

The relation between amniotic fluid surfactant concentration in preterm labour and histological evidence of chorioamnionitis

Summary Concentration of amniotic fluid disaturated phosphatidylcholine (DSPC), factors related to cervical ripening, and histopathological evidence of chorioamnionitis were studied in 38 patients in preterm labour with intact membranes; all of them delivered spontaneously before 37 weeks. There was no correlation between the amniotic fluid DSPC level and gestational age at the time of amniocentesis. However, a significant inverse correlation was found between the amniotic fluid DSPC level and the interval between the onset of labour and delivery. The amniotic fluid DSPC level in cases with onset-delivery interval of <48h was significantly higher than that in cases with an onsetdelivery interval of 48h or more. The gestational age in the former group was significantly lower than in the latter (28.6 vs 32.0 weeks). The amniotic fluid DSPC level in the patients with chorioamnionitis was significantly higher than that in the patients without chorioamnionitis, although the gestational age did not differ between the two groups. All 3 infants with RDS were associated with cervical incompetence. Patients in preterm labour with chorioamnionitis may be refractory to tocolysis and have higher amniotic fluid surfactant levels.     

Resistin in mid-trimester amniotic fluid in trisomy 21

Abstract

Objective: The aim of this study was to examine whether resistin is present in second trimester amniotic fluid from trisomy 21 (also known as Down’s syndrome) pregnancies and whether its concentration differs compared with euploid pregnancies.

Methods: The study cohort consisted of 58 women in the mid-trimester of pregnancy who underwent amniocentesis for prenatal diagnosis, 31 of whom carried a single fetus with diagnosed trisomy 21 (study group) and the rest with normal karyotype (control group, n?=?27). Groups were matched for maternal and gestational age. Levels of resistin in amniotic fluid were measured by a commercially available enzyme-linked immunosorbent assay (ELISA) kit.

Results: Resistin was detected in all amniotic fluid samples. Its median concentration in the second trimester amniotic fluid of trisomy 21 pregnancies (2.1?ng/ml) was statistically significantly lower (p value <0.001) in comparison with that in euploid pregnancies (3.3?ng/ml).

Conclusions: Resistin is a physiologic constituent of second trimester amniotic fluid. Lower levels of amniotic fluid resistin in pregnancies with trisomy 21 may reflect altered metabolic pathways in utero that could possibly be related with phenotypic features of the syndrome.     

Amniotic fluid Interleukin-8 as a marker for intraamniotic infection

Summary We measured the amniotic fluid Interleukin-8 (AF IL-8) levels of 80 women to see whether or not AF IL-8 levels were of value in the diagnosis of intraamniotic infection. Of twelve patients developing conventional signs of infection, 9 had an AF IL-8 concentration above 10.000 pg/ml serum. In two patients, whose baby had a serious neonatal infection, AF IL-8 concentration also exceeded 10.000 pg/ml. Only one out of 66 apparently uninfected patients had an AF IL-8 level above 10.000 pg/ml. We therefore suggest that measuring the AF IL-8 levels is of value in cases of suspected intraamniotic infection.     

High interleukin-16 concentrations in the early second trimester amniotic fluid: an independent predictive marker for preterm birth

Objective: Infection is believed to be one of frequent and important causes of preterm labor. We attempted to evaluate whether the level of inflammatory markers, e.g. interleukin-16 (IL-16), interleukin-18 (IL-18), and ferritin, in amniotic fluid at early second trimester can predict preterm birth. Methods: Amniotic fluid (AF) samples were collected from 350 pregnant women who had trans-abdominal amniocentesis for genetic indications at 16 to 20 weeks of gestation. AF levels of IL-16, IL-18 and ferritin levels were measured by immunoassay and were correlated with pregnancy outcomes. Results: Among the 350 pregnant women, 58 (16.6%) had preterm birth (<37 weeks gestation). AF levels of IL-16, IL-18, and ferritin were significantly higher in pregnant women with subsequent preterm birth. Multivariate analyses showed that a quartile higher of AF IL-16 level was significantly associated with preterm birth (OR: 3.09, 95% CI 1.52–6.27, p = 0.002). A receiver operating characteristic analysis revealed that an IL-16 cutoff value of 105 pg/ml was a reliable predictor of preterm birth (sensitivity, 90.2%; specificity, 52.7%; negative predictive value, 84.3%). Conclusion: It is feasible to predict preterm birth by measuring the AF levels of IL-16 especially for the pregnant women requiring genetic amniocentesis during early second trimester.     

Residual amniotic fluid volume predicts the sealing of preterm prelabor rupture of fetal membranes in the pre- and periviable period

ObjectivePreterm prelabor rupture of fetal membranes (pPROM) is a leading cause of preterm birth. When pPROM occurs around the pre- and periviable period, the perinatal outcome is unfavorable. However, there have been a few cases in which the leakage of amniotic fluid ceases and the ruptured fetal membranes are spontaneously sealed.Materials and methodsThe prognosis of 38 cases of pPROM at less than 27 weeks of gestation in Kyoto University Hospital were studied. The clinical factors related to the sealing of fetal membranes were investigated.ResultsSpontaneous sealing was confirmed in five patients (13%), and sealing occurred within 14 days of pPROM. Women in the no sealing group delivered at 26.3 ± 0.5 weeks of gestation, whereas women in the sealing group delivered at term at 38.8 ± 0.4 weeks (p < 0.0001). The maximum vertical pocket (MVP) of amniotic fluid at the time of pPROM diagnosis was 2.2 ± 0.3 cm in the no sealing group and 3.8 ± 0.5 cm in the sealing group (p = 0.043). All cases of sealing occurred when the MVP at diagnosis was more than 2 cm, and there were no cases of sealing if the MVP at diagnosis was less than 2 cm. In addition, the value of C-reactive protein at ROM was less than 0.4 mg/dL in all cases in the sealing group.ConclusionThe residual volume of sterile amniotic fluid at the onset of pPROM may predict the possibility of fetal membrane sealing.     

超声测量羊水指数和宫颈管长度预测未足月胎膜早破患者分娩潜伏期的价值

目的:探讨超声测量羊水指数(AFI)和宫颈管长度(CL)预测未足月胎膜早破(PPROM)患者分娩潜伏期的价值。方法:选择2009年10月至2014年10月我院收治的198例PPROM患者,入院后6h内超声检查测量AFI和CL。根据分娩潜伏期分为7日内分娩组和7日后分娩组,比较两组的病史、临床特点及超声指标,评估CL及AFI预测PPROM患者7日内分娩的特异性及敏感性。结果:(1)7日内分娩组患者破膜时伴阴道流血率、破膜时伴有宫缩率和新生儿转NICU率均高于7日后分娩组,差异有统计学意义(P0.05);(2)7日内分娩组患者的AFI、CL和分娩潜伏期均小于7日后分娩组患者,差异有统计学意义(P0.05);(3)CL≤2cm联合AFI≤5cm预测PPROM患者7日内分娩具有较高的敏感性及特异性(灵敏度82%,特异度51%);(4)以破膜后7日内是否分娩为应变量,经二分类logistic回归分析显示,破膜时伴阴道流血、破膜时伴有宫缩、CL≤2cm、AFI≤5cm是PPROM后7日内分娩的有效自变量(P0.05)。结论:超声测量AFI和CL对预测PPROM患者7日内是否分娩有一定价值,TVCL≤2cm联合AFI≤5cm能提高预测PPROM患者7日内分娩的敏感性及特异性。     

Pentraxin 3 in amniotic fluid as a marker of intra-amniotic inflammation in women with preterm premature rupture of membranes

Objective

To determine whether amniotic fluid levels of pentraxin 3 (PTX3) are of value in the prenatal diagnosis of acute histological chorioamnionitis in preterm premature rupture of membranes (PPROM).

Methods

Forty pregnant women with PPROM between 24 and 36 weeks of pregnancy without (n = 21) and with (n = 19) histological chorioamnionitis (PPROM group) and 42 women between 16 and 20 weeks of pregnancy (midtrimester group) were included in the study. We compared amniotic fluid PTX3 levels in the PPROM group with versus without histological chorioamnionitis, and between the PPROM and the midtrimester groups using nonparametric tests (Mann-Whitney test), given the non-normal distribution of the analyte.

Results

Patients with histological chorioamnionitis had a significantly higher median amniotic fluid PTX3 concentration than patients without the histological signs of chorioamnionitis (3.69 ng/mL [0.51-106.8] versus 0.8 ng/mL [0.36-121.0]; P = 0.015). Patients in the PPROM group reached a significantly higher median amniotic fluid concentration of PTX3 compared with those in the midtrimester group (1.0 ng/mL [0.36-121.0] versus 0.67 ng/mL [0.4-2.8]; P = 0.007).

Conclusion

Histological chorioamnionitis is associated with a significant increase of amniotic fluid pentraxin 3 levels. Amniotic fluid pentraxin 3 appears to be a marker of intra-amniotic inflammation.     

Elevated placenta growth factor levels in the early second-trimester amniotic fluid are associated with preterm delivery

Objective: The purpose of this study was to determine how angiogenesis-related factors correlate with preterm delivery.

Methods: A cohort of 382 pregnant women undergoing early second-trimester genetic amniocentesis was enrolled and followed-up until delivery, and the amniotic fluid was collected and stored as a nested case-control study. Cases with preterm delivery (n?=?31) were compared with matched controls with term delivery (n?=?62). The amniotic fluid concentrations of placenta growth factor (PlGF), angiogenins, angiopoietin-2, soluble fms-like tyrosine kinase and soluble endoglin were determined using enzyme-linked immunosorbent assays.

Results: Women who delivered preterm had a higher amniotic PlGF concentration compared with the control group (median 12.6 pg/ml versus 6.1 pg/ml; p=0.027). Other angiogenesis-related factors did not show any differences between case and control groups. The odds ratio for preterm delivery based on amniotic fluid PlGF was 1.031 (95% confidence interval: 1.002–1.061; p=0.035). Additionally, when the cases were subdivided into early preterm, late preterm and term groups, PlGF values between the early preterm and term delivery groups were significantly different (median 16.6 pg/ml versus 6.1 pg/ml; Bonferroni-adjusted p=0.018).

Conclusion: Amniotic fluid PlGF levels in the early second trimester of pregnancy are associated with preterm delivery.     

Ex vivo cytokine production by whole mid-trimester amniotic fluid

We hypothesized that ex vivo measurement of intraamniotic production of immune mediators differed from analysis of these mediators within unincubated amniotic fluid. Mid-trimester amniotic fluid from 72 women were incubated ex vivo with or without 50 ng/ml lipopolysaccharide (LPS). Supernatants and the corresponding unincubated amniotic fluids were tested for interleukin (IL)-6, IL-1 receptor antagonist (IL-1ra), IL-10 and nitric oxide. Ex vivo culture resulted in increased release of IL-6, IL-10 and nitric oxide; IL-1ra levels were decreased following the incubation. A spontaneous preterm birth (SPTB) occurred in 12 (16.7%) of the subjects. Women with a subsequent SPTB had decreased IL-6 and increased IL-10 production following ex vivo culture compared to women with a term delivery. This association was not evident with unincubated amniotic fluids. Conversely, IL-1ra concentrations were elevated in women with subsequent SPTB only in unincubated amniotic fluids. Immune mediator production by ex vivo amniotic fluid culture differs from that present in amniotic fluid supernatants and may provide a more accurate indication of the immune potential of the intraamniotic environment.     

Expression of cytokines and chemokines in cervical and amniotic fluid: Relationship to histological chorioamnionitis

Objective. To correlate cervical and amniotic fluid cytokines and macrophage-related chemokines to the development of histological chorioamnionitis (HCA) in patients with preterm labor (PTL) and preterm prelabor rupture of the membranes (PPROM).

Study design. Cervical and amniotic fluid interleukin (IL)-6, IL-8, IL-18, monocyte chemotactic protein (MCP)-1, MCP-2, and MCP-3 from pregnant women (at ≤34 weeks of gestation) in PTL (N = 42) were analyzed and related to the subsequent occurrence of HCA or inflammatory signs in the placenta. For the patients with PPROM (N = 30) only amniotic fluid proteins were analyzed.

Results. Intra-amniotic levels of IL-6, IL-8, IL-18, MCP-1, and MCP-3 were significantly higher in PTL cases with HCA compared to non-HCA controls, whereas no such relationship was obtained in the PPROM group. Cervical IL-8 and IL-6 (but not IL-18, MCP-1, MCP-2, and MCP-3) in PTL patients was associated with HCA, and at a cut-off level of 10.0 ng/mL cervical IL-8 was a strong predictor of HCA in the PTL cases (sensitivity 100%, specificity 67%, positive predictive value 63%, negative predictive value 100%). The cytokine and chemokine levels in the group with inflammatory signs were generally higher than in controls but lower compared to the concentrations in the HCA group.

Conclusions. The amniotic levels of IL-6, IL-8, IL-18, and the CC-chemokines MCP-1 and MCP-3 in PTL patients all predicted HCA, whereas only IL-8 was a clinically useful marker of HCA in the cervical fluid. In addition there is indication that the levels of inflammatory proteins are related to the degree of inflammatory infiltration in placental tissue samples.     

羊水乳酸水平对羊水粪染病例胎儿窘迫的诊断价值

目的探讨羊水乳酸水平在羊水粪染病例中诊断胎儿窘迫的临床价值。方法2003年8月至2004年12月暨南大学第二临床医学院测定72例第一产程活跃期出现羊水粪染(观察组)和52例羊水清、胎儿监护图形正常且有良好新生儿结局(对照组)的羊水及新生儿脐动脉血乳酸水平。结果对照组羊水乳酸值近似正态分布,其95%参考值为5.4~8.9mmol/L。对照组活跃期和分娩时羊水乳酸水平差异无显著性意义(P>0.05)。羊水Ⅲ度粪染的羊水乳酸水平明显高于对照组(P<0.01)。羊水Ⅰ度及Ⅱ度粪染而胎儿监护正常的病例羊水乳酸值与对照组比较,差异无显著性意义(P>0.05)。但羊水Ⅱ度粪染合并胎心基线异常或(和)重度变异减速病例的羊水乳酸水平明显升高(P<0.01)。观察组发生胎儿窘迫及新生儿窒息的病例,其活跃期羊水乳酸水平均明显高于对照组(P<0.01)。以活跃期羊水乳酸值>8.9mmol/L为异常值来诊断胎儿窘迫发生的敏感性、特异性、阳性预测值及阴性预测值分别为61.9%、88.2%、68.4%和84.9%。结论羊水乳酸值测定对提高羊水粪染病例胎儿窘迫的诊断准确性有一定临床价值。     

Cervicovaginal HCG and cervical length for prediction of preterm delivery in asymptomatic women at high risk for preterm delivery

Objective  To predict the risk of preterm birth (<37 weeks) or early preterm birth (<34 weeks) by cervicovaginal HCG and cervical length measured between 24–28 weeks of gestation in asymptomatic women at high risk for preterm birth. Methods  This study was conducted in the departments’ of Obstetrics & Gynaecology and Immunopathology of the Postgraduate Institute of Medical Education and Research, Chandigarh, India. In 75 pregnant women at high risk for preterm birth because of prior one on more preterm births due to spontaneous labour or ruptured membranes, cervicovaginal HCG and cervical length (by TVS) were measured between 24–28 weeks of gestation. These parameters were correlated individually and in combination for prediction of preterm birth. Results  Of the 75 women, 20 (26.7%) delivered <37 weeks and 6 (8%) delivered <34 weeks. To predict delivery <37 weeks, cervical length <2.95 cm had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 75%, 80.1%, 71.4% and 90.7% respectively, and cervicovaginal HCG >4.75 mIU/ml had a sensitivity, specificity, PPV, and NPV of 70%, 61.81%, 40% and 85% respectively. To predict delivery <34 weeks, cervical length <2.65 cm had a sensitivity, specificity, PPV, and NPV of 50%, 85.50%, 23.08% and 95.16% respectively; and cervicovaginal HCG >14 mIU/ml had a sensitivity, specificity, PPV and NPV of 83.3%, 85.5%, 33.3% and 98.3% respectively. Cervical length was superior to predict delivery <37 weeks, whereas HCG was superior to predict delivery <34 weeks. Their combination was superior to predict preterm birth both <37 weeks or <34 weeks, than either parameter used alone. Conclusion  In high risk asymptomatic women, increased cervicovaginal HCG and reduced cervical length and between 24 to 28 weeks of gestation increased the risk of preterm delivery.     

Monocyte chemotactic protein-1 in cervical and amniotic fluid: relationship to microbial invasion of the amniotic cavity, intra-amniotic inflammation, and preterm delivery

OBJECTIVE: The purpose of this study was to evaluate the role of monocyte chemotactic protein-1 in cervical and amniotic fluid in women in preterm labor and with preterm premature rupture of membranes. STUDY DESIGN: Women with singleton pregnancies (相似文献   

Galanin in the amniotic fluid and neonatal birth weight: a prospective observational study

Abstract

Objective: The aim of the present study was to examine whether an association is present between amniotic fluid (AF) galanin and neonatal birth weight (NBW).

Design: Prospective observational study.

Setting: Fetal maternal unit in a tertiary teaching hospital.

Population: Fifty women of singleton pregnancy who underwent amniocentesis during the second trimester and delivered after the 37th week of gestation.

Methods: Amniocentesis 18th–19th gestational week for genetic indication with the use of a 22G needle under real-time sonographic guidance and measurement of galanin concentration in the AF.

Main outcome measures: Association between concentration of AF galanin and NBW at term.

Results: Galanin was isolated in all samples of AF (median concentration 19.95?pg/mL; range: 19.0–21.7). A strong linear correlation between AF galanin and NBW was detected (τ?=?0.928; p?<?0.001). Non-parametric linear regression analysis revealed that galanin concentration could explain 72.1% of the variance in the NBW, when controlling for gestational week at birth and mother’s body mass index at delivery.

Conclusions: AF galanin during the second trimester seems to have a strong linear correlation with NBW of term deliveries in singleton pregnancies, even when controlling for important confounders.     

The role of amniotic fluid assessment in indicated preterm delivery

Measuring amniotic fluid pockets with ultrasound is an efficient and reasonably reliable method of evaluating amniotic fluid volume and categorizing relative risk of perinatal morbidity. The most commonly used ultrasound criteria for oligohydramnios, SDP <2 cm and AFI <5 cm, assign approximately 2%-3% and 4%-5% of late preterm pregnancies into the "low amniotic fluid" category. The AFI offers somewhat greater sensitivity and greater precision but has less specificity for predicting perinatal morbidity than does the SDP. Thus, before 34 weeks, use of the AFI <5 cm as a criterion for intensive fetal monitoring, but not as sole criteria for delivery, is recommended. In pregnancies beyond 34 weeks, use of either AFI or SDP to diagnose oligohydramnios can be expected to reliably identify fetuses at risk for compromised perinatal outcome especially if replicate measurements are confirmatory. In such cases, care must be taken to identify comorbid conditions that, together with oligohydramnios, may place the fetus at significant risk. In such cases, delivery is the recommended intervention.