Novel genetic and salivary glycan biomarkers for risk of NEC in ELBW infants.

描述(由申请人提供)：极低出生体重(ELBW，&lt；1000克)婴儿患NEC的发病率和病死率最高。缺乏预测NEC的生物标志物，特别是在ELBW婴儿中。令人兴奋的新数据表明，特定的岩藻糖化和唾液酸化的多糖可能是NEC的强大预测因子：H-2是由FUT2(分泌物)基因编码的岩藻糖基转移酶产生的主要糖基表位。唾液酸化路易斯a(sialyl Lewis a，SLE)是由FUT3和a2-3唾液酸基转移酶基因编码的转移酶联合催化作用产生的一种主要糖链。这些多糖在肠道表面的表达可以通过基因多态或通过测量唾液多糖来间接评估。我们的初步数据表明，与其他ELBW婴儿相比，唾液H-2水平低或缺失且Slea Glycan高的婴儿患NEC的风险高4倍，NEC病例的死亡风险高9倍，ELBW婴儿患NEC的死亡风险与他们的FUT2(“分泌物”)基因有关。因此，我们建议对在俄亥俄州辛辛那提和阿拉巴马州伯明翰的NICU登记的600名ELBW婴儿进行独特的研究，以检验以下假设：FUT2基因和唾液多糖表位是NEC风险的有力预测因子，它们也可以作为肠道细菌定植的生物标记物，并且它们单独或与其他生物标记物结合使用，极大地提高了我们预测ELBW婴儿NEC风险的能力。这项建议的具体目的是：1)检测FUT2基因型、唾液H-2和SLE表型作为NEC后续风险的新生物标记物；2)检测ELBW婴儿肠道细菌定植的模式与其糖链基因和表型、抗生素治疗病史和NEC结局的关系；以及3)确定包括多个可能的NEC风险生物标记物的多变量模型的预测价值，包括基因多态、唾液多糖和早期炎症指标。这项研究将收集用于遗传学研究的DNA，用于EIA抗原分子表型的连续唾液，以及用于微生物组分析的粪便。肠道细菌将通过16sDNA的实时定量定量聚合酶链式反应进行定量，综合微生物群将通过粪便样本的微阵列分析进行定量。标准化的临床数据将通过NICHD新生儿研究网络(NRN)数据系统获得，并辅之以图表审查。我们期待这项研究的结果将提供丰富的数据集，阐明肠道多糖表达的个体发育-微生物生态学及其与NEC的关系。该项目具有独特的潜力，可以指导转化研究来测试新的干预措施。此外，糖链表达的生物标记物可以被开发成监测早产儿的新工具。我们的建议通过寻找新的生物标记物直接解决RFA的几个目标；通过纳入早期炎症的生物标记物来改进多变量预测模型；以及促进对早产儿肠道生态的了解。公共卫生相关性：已知肠道早期细菌定植有益有助于预防坏死性小肠结肠炎(NEC)。定植过程导致胃肠道中含有岩藻糖和含唾液酸的糖类的数量发生变化。该项目将研究辛辛那提和伯明翰的600名极低出生体重儿，以测试唾液和控制这些糖合成的基因作为患NEC风险的新生物标记物和肠道定植的指标。

DESCRIPTION (provided by applicant): Extremely low birth weight (ELBW, <1000 gram) infants experience the highest incidence and case fatality of NEC. Biomarkers to predict NEC are lacking, especially in ELBW infants. Exciting new data indicate that specific fucosylated and sialylated glycans may serve as powerful predictors of NEC: H-2 is a major glycan epitope produced by the fucosyltransferase encoded by the FUT2 ("secretor") gene. Sialyl Lewis a (sLe ) is a major glycan produced by the combined catalytic function of transferases encoded by the FUT3 and a2-3 sialyl transferase genes. Expression of these glycans on the surface of the intestinal tract can be evaluated indirectly through gene polymorphisms or through measurement of salivary glycans. Our preliminary data indicate that risk of NEC is 4-fold higher and risk of death in NEC cases is 9-fold higher in infants with low or absent salivary H-2 and high sLea glycan compared to other ELBW infants, and that risk of death with NEC varies 5-fold among ELBW infants in relation to their FUT2 ("secretor") genotype. Thus, we propose a unique study of 600 ELBW infants enrolled in NICUs in Cincinnati, OH and Birmingham, AL, to test the hypotheses that FUT2 genotype and salivary glycan epitopes are strong predictors of risk of NEC, that they also function as biomarkers of intestinal bacterial colonization, and that alone or in combination with other biomarkers, they greatly improve our ability to predict risk of NEC in ELBW infants. The specific aims of this proposal are to: 1) Test FUT2 genotype and salivary H-2 and sLe phenotypes as novel biomarkers of subsequent risk of NEC; 2) Examine the pattern of intestinal bacterial colonization in ELBW infants in relation to their glycan genotype and phenotype, antibiotic treatment history, and NEC outcome; and 3) Determine the predictive value of multivariate models that include multiple putative biomarkers for risk of NEC, including gene polymorphisms, salivary glycans, and measures of early inflammation. This study will collect DNA for genetic studies, serial saliva for molecular phenotyping of antigens by EIA, and stool for microbiome analysis. Intestinal bacteria will be quantified through real-time qPCR of 16sDNA, and the comprehensive microbiome will be quantified by microarray analysis of stool samples. Standardized clinical data will be available through the NICHD Neonatal Research Network (NRN) data system augmented by chart review. We anticipate that the results of this study will provide a rich dataset that clarifies the ontogeny of intestinal glycan expression- microbial ecology and its relation to NEC. This project has unique potential to guide translational research to test novel interventions. Further, glycan expression biomarkers could be developed into new tools for monitoring premature infants. Our proposal directly addresses several objectives of the RFA by finding new biomarkers; improving multivariate predictive models by including biomarkers of early inflammation; and advancing understanding of the intestinal ecology of preterm infants. PUBLIC HEALTH RELEVANCE: Beneficial early bacterial colonization of the intestinal tract is known to help prevent necrotizing enterocolitis (NEC). The process of colonization causes a change in amounts of fucose-containing and sialic acid- containing sugars in the gastrointestinal tract. This project will study 600 extremely low birthweight infants in Cincinnati and Birmingham to test the measurement of saliva and the genes that control the synthesis of these sugars as novel biomarkers of risk of NEC and indicators of intestinal colonization.