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, <1000克）婴儿是NEC发病率和病死率最高的婴儿。缺乏预测NEC的生物标志物，特别是在新生儿中。令人兴奋的新数据表明，特定的聚焦化和唾液化聚糖可能是NEC的有力预测因子：H-2是由FUT2（“分泌”）基因编码的聚焦转移酶产生的主要聚糖表位。唾液酰刘易斯a （sLe）是由FUT3和a2-3唾液酰转移酶基因编码的转移酶联合催化作用产生的主要聚糖。这些聚糖在肠道表面的表达可以通过基因多态性或唾液聚糖的测量间接评估。我们的初步数据表明，与其他ELBW婴儿相比，低或无唾液H-2和高sLea聚糖的婴儿NEC的风险高4倍，NEC病例的死亡风险高9倍，并且与FUT2（“分泌物”）基因型相关的ELBW婴儿NEC死亡风险相差5倍。因此，我们提出了一项独特的研究，在俄亥俄州辛辛那提和阿拉巴马州伯明翰的600名ELBW婴儿入组nicu，以验证FUT2基因型和唾液聚糖表位是NEC风险的强预测因子的假设，它们也作为肠道细菌定殖的生物标志物，并且单独或与其他生物标志物联合使用，它们大大提高了我们预测ELBW婴儿NEC风险的能力。该提案的具体目的是：1)测试FUT2基因型和唾液H-2和sLe表型作为NEC后续风险的新生物标志物；2)研究ELBW婴儿肠道细菌定植模式与糖基因型和表型、抗生素治疗史和NEC结果的关系；3)确定多变量模型的预测价值，包括多种假定的NEC风险生物标志物，包括基因多态性、唾液聚糖和早期炎症指标。本研究将收集DNA进行基因研究，收集唾液序列进行抗原分子表型分析，收集粪便进行微生物组分析。通过16sDNA的实时qPCR对肠道细菌进行定量，通过粪便样品的微阵列分析对综合微生物组进行定量。标准化的临床数据将通过NICHD新生儿研究网络（NRN）数据系统通过图表审查增强。我们预计本研究的结果将提供丰富的数据集，阐明肠道聚糖表达的个体发生-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，以测试新的干预措施。此外，聚糖表达生物标志物可以发展成为监测早产儿的新工具。我们的建议通过寻找新的生物标志物直接解决了RFA的几个目标；通过纳入早期炎症的生物标志物来改进多变量预测模型；促进对早产儿肠道生态的理解。

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.