Untargeted metabolic screening of preterm infants on a human milk diet

Aim. This dataset includes metabolic fingerprints of preterm infants exclusively receiving (≥ 80% of total intake) either donor human milk (DHM) provided by a Human Milk Bank (N=20) or own mother’s milk (OMM) (N=20) recorded using a LC-QTOFMS instrument from urine samples collected at one month of age. The dataset was used to assess nutrition-derived changes in preterm infants at the phenotype level in a non-invasive manner.

Study population and urine collection. A prospective, observational cohort study was conducted including consecutively admitted preterm infants born at ≤32 weeks of gestation and/or birth weight ≤1500 g in the Division of Neonatology of the University and Polytechnic Hospital La Fe (Valencia, Spain). Two groups were recruited according to the main feeding type accounting for ≥80% v/v of the nutritional intake with either OMM or pasteurized DHM after achieving full enteral nutrition (150 mL/kg/day).
Urine samples were collected from infants exclusively receiving DHM (N=20) or OMM (N=20) one month after birth using sterile cotton pads placed in the diaper. Cotton pads were retrieved after one hour and squeezed with a syringe. The process was repeated until a minimum volume of 1 mL was collected. Urine samples were stored at −80 ⁰C until analysis.

Sample preparation. Urine samples were thawed on ice and thoroughly shaken on a Vortex® mixer during 10 s followed by centrifugation at 16 000 x g and 4 ⁰C during 10 min. 50 μL of supernatant were added to 50 μL of an internal standard (IS) solution containing reserpine, phenylalanine-D5, leucine-enkephalin, caffeine-D9, and methionine-D3 at 2 μM each in H2O:CH3CN (96:4, 0.1% HCOOH v/v) and transferred to a 96-well plate. A blank extract was prepared using water instead of urine and following the same procedure as described for urine samples. A pooled quality control (QC) sample was prepared by mixing 5 μL of each study sample.