Longitudinal analysis of urinary I-FABP in extremely preterm infants that develop necrotizing enterocolitis.

BACKGROUND

Intestinal fatty acid binding protein (I-FABP) is an intestinal epithelial protein detectable in infants with necrotizing enterocolitis (NEC). The longitudinal behavior of I-FABP following NEC or its association with gastrointestinal or neurodevelopmental outcomes is unknown.

METHODS

In this secondary analysis of the Preterm Erythropoietin Neuroprotection Trial, we compared infants with and without NEC. Urine I-FABP concentrations in matched infants (n = 70) were measured serially using ELISA and compared using paired analysis. In infants with NEC, the associations of I-FABP levels with short-term outcomes and neurodevelopmental outcomes at 22-26 months corrected age were determined using non-parametric analysis.

RESULTS

Infants with NEC were more likely to have cholestasis, death or severe neurodevelopmental impairment, cerebral palsy, and lower Bayley-III motor scores. Baseline urinary I-FABP levels were similar between groups. When compared to controls, infants with NEC had urinary I-FABP concentrations that were higher at diagnosis (median 11 vs 2.6 ng/ml, p = 0.006) and lower post-NEC (median 1 vs 5 ng/ml, p = 0.002). Diagnosis I-FABP levels were not associated with gastrointestinal or neurodevelopmental outcomes at 22-26 months corrected age.

CONCLUSIONS

In extremely preterm infants, urinary I-FABP was elevated at NEC diagnosis and lower post-NEC compared to matched controls. I-FABP levels were not associated with adverse gastrointestinal or neurodevelopmental outcomes.

IMPACT: Urinary intestinal fatty acid binding protein (I-FABP) levels are increased at diagnosis of NEC and fall to below baseline after NEC in extremely preterm infants. Urine I-FABP levels at NEC diagnosis are not associated with cholestasis, intestinal stricture or obstruction, need for additional intestinal surgery after NEC, or neurodevelopmental outcomes at 22-26 months corrected age. Urine I-FABP levels may be useful in the diagnosis of NEC. Diagnostic I-FABP levels do not predict short-term gastrointestinal or neurodevelopmental outcomes after NEC.