Plasma levels of conjugated bile acids in newborns after a short period of parenteral nutrition.

Background: Patients receiving parenteral nutrition (PN) frequently exhibit liver dysfunction. The authors previously reported that plant sterols of lipid emulsions added to the nutritional solution of newborns receiving PN accumulate in plasma and cell membranes and may contribute to the development of cholestasis. Conjugated bile acids (BA) have been shown to be useful markers of cholestasis. Plasma levels of several BA in newborns were quantified after administration of PN for less than 2 weeks. Methods: Plasma samples from 15 healthy control infants (CN), 22 patients who had received PN for 3-15 days (T1), and 9 patients scheduled to receive PN (T0) were analyzed. After a simple extraction procedure, plasma BA were analyzed by liquid chromatography-tandem mass spectrometry using a quantitative isotope dilution method. Results: The concentrations of BA did not differ significantly between controls and patients before PN (CN vs T0), with the exception of glycocholic acid (GCA; 2.30 ± 2.60 ??M vs 7.29 ± 5.39 ??M, respectively). There was a significant difference in several BA between controls and patients after PN (2.30 ± 2.60 ??M vs 7.61 ± 6.46 ??M for GCA, respectively; 4.02 ± 3.49 ??M vs 11.88 ± 11.05 ??M for taurocholic acid [TCA], respectively; and 4.81 ± 3.49 ??M vs 13.58 ± 12.22 ??M for taurochenodeoxycholic + taurodeoxycholic + tauroursodeoxycholic acids [TCDCA+TDCA+TUDCA], respectively). Conclusions: In newborns receiving PN, a short period of PN is associated with an early increase of some conjugated BA. These results suggest that GCA, TCA, and TCDCA+TDCA+TUDCA levels could be used as early markers of PN-related cholestasis.