The Role Of Subclinical Infection And Cytokines In Preterm Parturition

亚临床感染和细胞因子在早产中的作用

基本信息

批准号：
8941476
负责人：
ROBERTO ROMERO
金额：
$ 2048.67万
依托单位：
EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8941476
关键词：
Acute Adrenergic beta-Agonists Affect Amniotic Fluid Anaerobic Bacteria Antibiotic Therapy Bacteria Bacterial Vaginosis Base Sequence Bedside Testings Biological Assay Birth Calcium Channel Blockers Cervix Uteri Communities Control Groups Detection Development Diagnosis Diagnostic Disease Ecology Ecosystem Electrons Endometritis Endotoxins Enzymes Equation Frequencies Future Gardnerella Generations Genetic Genital system Genome Genomics Gestational Age Goals Gram-Negative Bacteria Histologic Hour Human body Immune response Individual Infant Infection Infection of amniotic sac and membranes Inflammation Inflammatory Inflammatory Response Injury Interleukin-6 Intervention Lactobacillus Lesion Light Mass Spectrum Analysis Mechanics Meconium Meconium Aspiration Membrane Meta-Analysis Methods Microbe Mobiluncus Modeling Molecular Morbidity - disease rate Mucous Membrane Nitroglycerin Oropharyngeal Pathogenesis Pathologic Processes Patients Perinatal Perinatology Phospholipase A2 Placenta Predisposing Factor Predisposition Pregnancy Pregnant Women Premature Birth Premature Labor Prevention Prevotella Procedures Relative (related person)Reporting Research Risk Risk Factors Role Sampling Series Staining method Stains Structure Suction Surveys Syndrome Taxon Techniques Technology Testing Time Tocolysis Tocolytic Agents Trichomonas vaginalis United States Vagina Virus Woman clinical risk cost cytokine fetal gene environment interaction human disease improved indexing intraamniotic infection ionization microbial microorganism mortality neonatal sepsis neonate pregnant premature prevent pyrosequencing rRNA Genes rapid diagnosis systematic review tool uterine contractility vaginal fluid

项目摘要

A central question is why some women develop an ascending intra-amniotic infection, while whereas most do not. The relationship between the mucosa of the lower genital tract (vagina and cervix) and the microbial ecosystem appears to be a key factor predisposing to ascending infection. Bacterial vaginosis a change in the microbial ecosystem in which there is proliferation of anaerobic bacteria confers risk for intra-amniotic infection and spontaneous preterm delivery. Similarly, trichomonas vaginalis infection is a risk factor for preterm delivery. However, antibiotic treatment of asymptomatic women with bacterial vaginosis or trichomonas vaginalis has not reduced the rate of preterm delivery. A comprehensive understanding of microbial ecology, genetic factors that control susceptibility to infection and the inflammatory response is required, particularly in light of evidence that gene-environment interactions may predispose to preterm labor (2). Characterization of the microbial composition of ecological niches in the human body, including the vagina, using culture-independent techniques, is now possible. This year, we reported a study which showed that the composition and stability of the vaginal microbiota of normal pregnant women is different from that of non-pregnant women. This included non-pregnant women (N=32) and pregnant women who delivered at term (38-42 weeks) without complications (n = 22). Serial samples of vaginal fluid were collected from both non-pregnant and pregnant patients. A 16S rRNA gene sequence-based survey was conducted using pyrosequencing to characterize the structure and stability of the vaginal microbiota. Linear mixed effects models and generalized estimating equations were used to identify the phylotypes whose relative abundance was different between the two study groups. The vaginal microbiota of normal pregnant women was different from that of non-pregnant women (higher abundance of Lactobacillus vaginalis, L. crispatus, L. gasseri and L. jensenii and lower abundance of 22 other phylotypes in pregnant women). Bacterial community state type (CST) IV-B or CST IV-A characterized by high relative abundance of species of genus Atopobium as well as the presence of Prevotella, Sneathia, Gardnerella, Ruminococcaceae, Parvimonas, Mobiluncus and other taxa previously shown to be associated with bacterial vaginosis were less frequent in normal pregnancy. The stability of the vaginal microbiota of pregnant women was higher than that of non-pregnant women; however, during normal pregnancy, bacterial communities shift almost exclusively from one CST dominated by Lactobacillus spp. to another CST dominated by Lactobacillus spp.(3). We then conducted a study to determine whether the vaginal microbiota of pregnant women who subsequently had a spontaneous preterm delivery is different from that of women who had a term delivery. We included a control group of pregnant women who had a term delivery and those who had a spontaneous preterm delivery before 34 weeks of gestation (cases). Samples of vaginal fluid were collected longitudinally and stored at −70C until assayed. A microbial survey using pyrosequencing of V1-V3 regions of 16S rRNA genes was performed, and we tested the hypothesis of whether the relative abundance of individual microbial species (phylotypes) was different between women who had a term versus preterm delivery. The findings were that: the composition of the vaginal microbiota during normal pregnancy changed as a function of gestational age, with an increase in the relative abundance of four Lactobacillus spp., and decreased in anaerobe or strict-anaerobe microbial species as pregnancy progressed; however, no change in the relative abundance of bacterial taxa was observed between women who had a spontaneous preterm delivery and those who delivered at term. The same was the case for the frequency of the vaginal community state types (CST I, III, IV-B). These early findings suggest that changes in the vaginal microbiota are not easily detected in women who subsequently have a spontaneous preterm delivery. Future studies need to take into consideration the indices of the maternal immune response and functional aspects of the vaginal microbiota (4). Meconium-stained amniotic fluid (MSAF) affects 5-20% of all pregnancies (400,000-600,000 deliveries per year in the United States alone), and is a risk factor for meconium aspiration syndrome (MAS); however, only 5% of infants with MSAF develop MAS. A critical question is why some neonates exposed to meconium develop this syndrome, and others do not. Attempts to prevent MAS with mechanical methods such as oropharyngeal, nasopharyngeal and tracheal suctioning and amnioinfusion have been attempted, but none have proven effective. Patients with MSAF are at increased risk for clinical chorioamnionitis, puerperal endometritis, neonatal sepsis, and intra-amniotic infection. Therefore, we conducted a series of studies to determine if MSAF was associated with the presence of bacteria in the amniotic fluid or bacterial products such as endotoxin. We found that 19% of patients with MSAF have microorganisms detected by culture, and there were frequently gram-negative bacteria. Endotoxin was detected in 46% of patients with MSAF, and these patients were also more likely to have intra-amniotic inflammation (an elevation in AF IL-6). In a separate study, we found that MSAF containing bacterial endotoxin also had a higher concentration of secreted phospholipase A2, an enzyme implicated in the pathogenesis of MAS. Studies are now in progress to determine if fetal systemic inflammation may be a predisposing factor for the development of MAS (5). The mainstay for the treatment of preterm labor remains arresting uterine contractility (tocolysis). We previously reported systematic reviews and meta-analyses of calcium-channel blockers for this indication. This year, we reported a systematic review and meta-analysis of transdermal nitroglycerin for the treatment of preterm labor. We found that, although transdermal nitroglycerin appears to be more effective than beta adrenergic receptor agonists, the current evidence does not support its routine use as a tocolytic agent for the treatment of preterm labor (6).

一个核心问题是为什么有些女性会出现上行性羊膜内感染，而大多数女性却不会。下生殖道（阴道和子宫颈）粘膜与微生物生态系统之间的关系似乎是导致上行感染的关键因素。细菌性阴道病是微生物生态系统的变化，其中厌氧菌增殖，导致羊膜内感染和自发性早产的风险。同样，阴道毛滴虫感染也是早产的危险因素。然而，对患有细菌性阴道病或阴道毛滴虫的无症状妇女进行抗生素治疗并没有降低早产率。需要全面了解微生物生态学、控制感染易感性和炎症反应的遗传因素，特别是有证据表明基因-环境相互作用可能导致早产 (2)。现在可以使用独立于培养的技术来表征人体（包括阴道）生态位的微生物组成。今年，我们报道了一项研究，该研究表明，正常孕妇的阴道微生物群的组成和稳定性与非孕妇不同。其中包括非孕妇 (N = 32) 和足月分娩（38-42 周）且无并发症的孕妇 (n = 22)。从非怀孕和怀孕患者收集阴道液体的系列样本。使用焦磷酸测序进行基于 16S rRNA 基因序列的调查，以表征阴道微生物群的结构和稳定性。使用线性混合效应模型和广义估计方程来识别两个研究组之间相对丰度不同的系统发育型。正常孕妇的阴道微生物群与非孕妇不同（孕妇阴道乳杆菌、卷曲乳杆菌、格氏乳杆菌和詹氏乳杆菌丰度较高，而其他 22 种系统型的丰度较低）。细菌群落状态类型 (CST) IV-B 或 CST IV-A，其特征是 Atopobium 属物种的相对丰富度以及普雷沃菌属、Sneathia、Gardnerella、Ruminococcaceae、Parvimonas、Mobiluncus 和其他先前显示相关的类群的存在细菌性阴道病在正常妊娠中较少见。孕妇阴道菌群稳定性高于非孕妇；然而，在正常怀孕期间，细菌群落几乎完全从以乳杆菌属为主的 CST 转变。到另一个以乳杆菌属 (Lactobacillus spp.) 为主的 CST (3)。然后我们进行了一项研究，以确定随后自然早产的孕妇的阴道微生物群是否与足月分娩的妇女不同。我们纳入了对照组，其中包括足月分娩的孕妇和妊娠 34 周前自然早产的孕妇（病例）。纵向收集阴道液样本并储存在-70°C直至进行分析。使用 16S rRNA 基因 V1-V3 区域的焦磷酸测序进行微生物调查，我们测试了足月分娩与早产女性之间单个微生物物种（系统发育型）的相对丰度是否不同的假设。研究结果表明：正常妊娠期间阴道微生物群的组成随胎龄的变化而变化，随着妊娠的进展，四种乳杆菌的相对丰度增加，而厌氧或严格厌氧微生物种类的相对丰度减少；然而，在自然早产的妇女和足月分娩的妇女之间，没有观察到细菌类群的相对丰度发生变化。阴道社区状态类型（CST I、III、IV-B）的频率也是如此。这些早期发现表明，在随后自然早产的女性中，阴道微生物群的变化不容易被检测到。未来的研究需要考虑母体免疫反应指标和阴道微生物群的功能方面 (4)。胎粪染色羊水 (MSAF) 影响 5-20% 的妊娠（仅在美国每年就有 400,000-600,000 次分娩），并且是胎粪吸入综合征 (MAS) 的危险因素；然而，只有 5% 患有 MSAF 的婴儿会发展为 MAS。一个关键问题是，为什么一些接触胎便的新生儿会出现这种综合征，而另一些则不会。已经尝试通过口咽、鼻咽和气管抽吸以及羊膜腔灌注等机械方法来预防 MAS，但均未证明有效。 MSAF 患者发生临床绒毛膜羊膜炎、产后子宫内膜炎、新生儿败血症和羊膜内感染的风险增加。因此，我们进行了一系列研究，以确定 MSAF 是否与羊水中存在细菌或内毒素等细菌产物有关。我们发现19%的MSAF患者培养检出微生物，且常有革兰氏阴性菌。 46% 的 MSAF 患者检测到内毒素，这些患者也更有可能出现羊膜内炎症（AF IL-6 升高）。在另一项研究中，我们发现含有细菌内毒素的 MSAF 还具有较高浓度的分泌型磷脂酶 A2，这种酶与 MAS 的发病机制有关。目前正在进行研究以确定胎儿全身炎症是否可能是发生 MAS 的诱发因素 (5)。治疗早产的主要方法仍然是抑制子宫收缩（安胎）。我们之前报道了针对该适应症的钙通道阻滞剂的系统评价和荟萃分析。今年，我们报告了经皮硝酸甘油治疗早产的系统评价和荟萃分析。我们发现，虽然透皮硝酸甘油似乎比 β 肾上腺素能受体激动剂更有效，但目前的证据并不支持其常规用作宫缩抑制剂来治疗早产 (6)。