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

<b><i>Background:</i></b> Necrotizing enterocolitis (NEC) is a major cause of death and morbidity in very low birth weight infants. <b><i>Objective:</i></b> To identify biomarker(s) that would predict NEC using buccal swab samples utilizing a proteomic approach. <b><i>Methods:</i></b> Cumulative buccal swab samples derived from very low birth weight preterm infants (&lt;32 weeks' gestational age and &lt;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. <b><i>Results:</i></b> 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. <b><i>Conclusion:</i></b> Our results suggest that interleukin-1 receptor antagonist is worthy of further studies to determine its utility in helping predict NEC.