Fat emulsion given to very low‐birthweight infants increases urinary l‐FABP

Abstract

In premature infants, many factors influence the function of renal tubules, such as asphyxia, respiratory disorders, use of high-concentration oxygen, hypotension, and drug treatment. When tubular ischemia and oxidative stress develop due to renal microcirculatory pathology, urinary L-type fatty acid-binding protein (L-FABP) level increases. Urinary L-FABP level was measured over time in very low-birthweight infants (VLBWI), and the effect of fat emulsion on L-FABP level was investigated. Thirty-one VLBWI were divided into two groups with regard to treatment with fat emulsion: the lipid group (n = 20) and the control group (n = 11). Urinary L-FABP was measured before (0-3 days of age), during (7-14 days of age), and after fat emulsion treatment (21-28 days of age) in the two groups. Median urinary L-FABP level before treatment was 459 ng/mgCr (range, 22.7-5100 ng/mgCr; mean, 1067 ± 1570 ng/mgCr) and 797 ng/mgCr (range, 69-3900 ng/mgCr; mean, 1066 ± 1188 ng/mgCr) in the lipid and control groups, respectively, showing no significant difference. Median urinary L-FABP level was 624 ng/mgCr (range, 50-2050 ng/mgCr; mean ± SD, 799 ± 655 ng/mgCr) and 273 ng/mgCr (range, 31-987 ng/mgCr; mean ± SD, 359 ± 323 ng/mgCr) at 7-14 days of age, respectively, showing that the level was significantly higher in the lipid group. At 21-28 days of age, the median level was 462 ng/mgCr (range, 49-1867 ng/mgCr; mean ± SD, 557 ± 534 ng/mgCr) and 130 ng/mgCr (range, 20-993 ng/mgCr; mean ± SD, 290 ± 329 ng/mgCr), respectively, showing that L-FABP level tended to be higher in the lipid group. Fat emulsion treatment induced a significant increase in urinary L-FABP level, suggesting that fat emulsion affected the proximal tubule in VLBWI.