Research Scientist UNC Chapel hill Chapel Hill., North Carolina, United States
Background: Necrotizing enterocolitis (NEC) is a severe intestinal disease that primarily occurs in preterm infants and results from a combination of uncontrolled inflammation, intestinal microbial dysbiosis, and irreversible epithelial cell injury. Rapid identification and treatment of neonates with NEC is critical to improving outcomes. Unfortunately, currently available diagnostic tools are inadequate, and poor specificity limits the clinical utility of previously identified biomarkers due to their detection of non-specific inflammation. We hypothesized that an unbiased proteomics assay performed on urine samples from a cohort of infants with and without disease would facilitate the identification of novel NEC biomarkers. Objective: Use a proteomic array to identify novel urine biomarkers for NEC. Design/Methods: After IRB approval and parental consent, urine samples were obtained from premature infants diagnosed with NEC (n=40) and compared to respective age- (n=8) or self-matched controls (n=12). Urine was desalted and normalized by total protein content. Protein abundance was detected using an aptamer-based SOMAscan microarray assay. Differentially abundant proteins were identified using median fold change of aptamer relative fluorescence unit (RFU) signals and significance, with log2 -1.2 to 1.2 median fold change and P < 0.05 cut-offs, respectively. Results: We detected 28 significantly increased and 45 significantly decreased proteins in the urine of infants with NEC relative to controls. Proteins with potential future utility as biomarkers were selected based on their association with inflammation or NEC and primary localization within intestinal epithelial cells. These proteins and the respective fold increase for NEC vs. controls include: regenerating family member 1 beta (REG1B, 9.2-fold), regenerating family member 3 alpha (REG3A, 2.6-fold), fatty acid binding protein 2 (FABP2, 3.0-fold), and defensin alpha 5 (DEFA5, 3.0-fold). The proteins also exhibited increased abundance in samples from infants with NEC with increasing Bell’s stage. In addition, receiver operating characteristic (ROC) curves indicate that REG1B (0.82) and REG3A (0.79) effectively differentiate infants with NEC from controls.
Conclusion(s): Differentially abundant proteins were detected in the urine of patients with and without NEC. Urine is a non-invasive and readily obtainable biological specimen, making it an ideal target for biomarker detection. Future studies with a larger cohort will be performed to validate these findings.
