Supplementary Material for: Pilot Study Using Proteomics to Identify Predictive Biomarkers of Necrotizing Enterocolitis from Buccal Swabs in Very Low Birth Weight Infants

Background: Necrotizing enterocolitis (NEC) is a major cause of death and morbidity in very low birth weight infants. Objective: To identify biomarker(s) that would predict NEC using buccal swab samples utilizing a proteomic approach. Methods: Cumulative buccal swab samples derived from very low birth weight preterm infants (<32 weeks' gestational age and <1,250 g) at 1, 2 and 3 weeks prior to the development of NEC and matched controls were subjected to two-dimensional difference gel electrophoresis and LC-MS/MS analysis for proteomic protein discovery. After identification of 21 altered proteins, we chose 3 candidate proteins using a broad systems biologic analysis approach that suggested several altered cellular processes that could be associated with NEC. Results: Preliminary validation studies using Western blots on these samples and 10 additional NEC and 10 matched control buccal samples collected within 2 or 3 weeks before NEC diagnosis analysis showed lower interleukin-1 receptor antagonist. Conclusion: Our results suggest that interleukin-1 receptor antagonist is worthy of further studies to determine its utility in helping predict NEC.