An Assessment of Urinary Intestinal Fatty Acid Binding Protein as a Early Predictor of Necrotizing Enterocolitis

Necrotizing enterocolits (NEC) occurs with an incidence of 3-7% in very low birth weight (<1500g) infants and is associated with significant morbidity and mortality. Earlier detection of a subclinical prodrome in NEC might allow for the institution of measures that could prevent or attenuate the severity of disease. We have demonstrated that levels of urinary intestinal fatty acid binding protein (iFABPu), a sensitive and specific marker for intestinal mucosal injury, were elevated in the first 4 days of life in all infants who subsequently developed NEC. We hypothesize that, in the context of an elevated iFABPu in the neonatal period, a significant proportion of NEC cases could be averted by not initiating feedings. The proposed study will be a three-year prospective trial of iFABPu monitoring during the neonatal period in 220 infants of gestational age less than 33 weeks. Urine will be collected in 12-hour aliquots over the first four days of life and the iFABPu will be measured. On the afternoon of day of life four, infants in whom iFABPu exceeded 1000 pg/ml at any time will be continued with no feedings, iFABPu will continue to be measured, and trophic, breast milk feedings will only be initiated after iFABPu has normalized for five days. Infants with non-elevated iFABPu over the first four days of life will have feedings initiated on day of life four, in the absence of other contraindications. All subjects will have urine collected daily over their entire hospital stay for iFABPu assay. However, after the active study period (after feedings have been initiated) iFABPu findings will not be communicated to the physicians caring for the subjects, but will be evaluated retrospectively in order to better define the utility of iFABPu as a marker for impending NEC later in newborn life. If iFABPu monitoring is shown to be effective in reducing the incidence of NEC it would revolutionize the care of premature infants by providing physicians with a tool that would permit feeding decisions to be based directly upon the viability of the intestine, rather than intuition.