Mucosal immune biomarkers to detect neonatal leaky gut

项目摘要 坏死性小肠结肠炎（NEC）是一种危及生命的胃肠道急症， 婴儿死亡率高达30- 50%。“肠漏”，或肠屏障不成熟，伴有肠壁升高 在早产新生儿中，血管通透性（IP）是NEC易感性的近因。泄漏的早期检测 肠道对于识别有NEC风险的婴儿以降低疾病严重程度至关重要。无临床因素，常规实验室检查 已经描述了单独或组合检测或生物标记物，其鉴定易患 NEC。我们推测，在粪便提取物中可检测到的粘膜免疫表型是肠道免疫的反映。 微环境和出生后屏障成熟，并可以区分婴儿在发展NEC的高风险。 本研究的目的是调查粪便免疫生物标志物的诊断价值，以确定“在风险” NEC发作前肠漏的新生儿。单独使用或与其他IP相关新生儿联合使用时 因素（即，月经后年龄，喂养，微生物群），免疫表型可以提供一个非 以粪便为基础侵入性方法检测新生儿肠漏。为了实现这一目标，我们将利用现有的凳子 从205名早产儿（<33周妊娠）的队列中收集样品，其中肠道微生物组（16 S rRNA基因测序和宏基因组）和IP（尿液非代谢糖探针乳果糖和鼠李糖） 是已知的。提出了两个目标：1）对细胞因子和趋化因子进行深入的表征， 早产儿出生后7-10天的粪便提取物，并确定粪便提取物的诊断价值。 免疫生物标志物在识别异常升高的IP作为NEC的主要风险因素中的作用; 2）定义 与IP改善或持续升高相关的粪便免疫生物标志物的纵向变化。在 完成这项研究后，我们将确定一个区别性的粘膜免疫表型， 一种新的、非侵入性的基于粪便的诊断/筛查工具，用于识别早产新生儿的“风险”， NEC。这项研究还将为宿主免疫与肠道微生物群之间的相互作用提供新的见解 在生命早期导致屏障损伤加剧的生态失调。这些结果将有助于临床研究， 评估合理设计的干预措施，以早期预防NEC，促进健康的肠道屏障 功能和新生儿健康。

PROJECT SUMMARY Necrotizing enterocolitis (NEC) is a life-threatening, gastrointestinal emergency affecting 7-10% of preterm infants with mortality as high as 30-50%. "Leaky gut", or intestinal barrier immaturity with elevated intestinal permeability (IP), is the proximate cause of susceptibility to NEC in preterm neonates. Early detection of leaky gut is essential to identify infants at risk for NEC to reduce disease severity. No clinical factor, routine laboratory test or biomarker alone or in combination have been described that identify newborns susceptible to develop NEC. We postulate that a mucosal immune phenotype detectable in fecal extracts, is reflective of the intestinal microenvironment and postnatal barrier maturation and can distinguish infants at high risk for developing NEC. The goal of this study is to investigate the diagnostic value of fecal immune biomarkers to identify “at-risk” neonates with leaky gut prior to NEC onset. When used alone or in combination with other IP-associated neonatal factors (i.e., postmenstrual age, feeding, microbiota), the immune phenotype can provide the basis of a non- invasive, stool-based method to detect neonatal leaky gut. To achieve this goal, we will leverage existing stool samples collected from a cohort of 205 preterms (<33 weeks gestation), from whom both gut microbiome (16S rRNA gene sequencing and metagenome) and IP (urine non-metabolized sugar probes lactulose and rhamnose) are known. Two aims are proposed: 1) to conduct an in-depth characterization of cytokines and chemokines in fecal extracts of preterm infants during the first 7-10 days of life, and to determine the diagnostic value of fecal immune biomarkers in identification of aberrantly elevated IP as a major risk factor for NEC; 2) to define longitudinal changes of fecal immune biomarkers associated with improved or persistently elevated IP. At the completion of this study, we will have identified a discriminatory mucosal immune phenotype representing a novel, non-invasive stool-based diagnostic/screening tool to identify preterm newborn “at risk” for developing NEC. This study will also provide new insights into the interplay between host immunity and gut microbiota dysbiosis that contributes to heightened barrier injury in early life. These results will facilitate clinical studies to evaluate rationally designed interventions for early NEC prevention and to promote healthy intestinal barrier functions and newborn health.