Aims
To identify serum concentrations of intestinal-specific protein(s) in infants with intestinal injury and controls.
Background
Neonates are at risk of gastrointestinal emergencies including necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP). Identifying biomarkers to aid in diagnosis is imperative. We hypothesized that circulating intestinal-specific protein concentrations would distinguish infants with intestinal injury from controls. Aims: To identify serum concentrations of intestinal-specific protein(s) in infants with intestinal injury and controls.
Conclusions
Of the intestinal-specific proteins evaluated, circulating Gal-4 concentrations were at the assay detection limit in control infants. Gal-4 concentrations were significantly elevated in infants with surgical NEC or SIP, suggesting that Gal-4 may serve as a biomarker for neonatal intestinal injury.
Methods
We used an in silico approach to identify intestinal-specific proteins. We collected serum from control infants and infants with NEC or SIP and measured protein concentrations using ELISA. If baseline concentrations were near the detection limit in initial control assays, we proceeded to assess concentrations in a larger cohort of controls and infants with injury. Control infants were frequency matched to infants with injury and compared with nonparametric and mixed-effects models analysis.
Results
We evaluated four proteins with high intestinal expression: Galectin-4 (Gal-4), S100G, Trefoil Factor-3, and alanyl aminopeptidase. Only Gal-4 demonstrated consistent results near the lower limit of quantification in controls and was studied in the larger cohorts. Gal-4 concentration was low in 111 control infants (median 0.012 ng/ml). By contrast, Gal-4 was significantly increased at diagnosis in infants with surgical NEC and SIP (n = 14, p ≤ 0.001 and n = 8, p = 0.031) compared to matched controls, but not in infants with medical NEC (n = 32, p = 0.10). Conclusions: Of the intestinal-specific proteins evaluated, circulating Gal-4 concentrations were at the assay detection limit in control infants. Gal-4 concentrations were significantly elevated in infants with surgical NEC or SIP, suggesting that Gal-4 may serve as a biomarker for neonatal intestinal injury.