Effects of lipid-supplemented total parenteral nutrition on fatty liver disease in a premature neonatal piglet model.

BACKGROUND Routine total parenteral nutrition (TPN) in neonatal care can result in hepatic dysfunction in 40-60% of patients, most commonly as fatty liver, but little work has been conducted on the underlying mechanisms causing hepatic dysfunction. OBJECTIVE To use a piglet model for the premature human neonate on TPN, supplemented with lipid emulsions, to investigate hepatic responses. METHOD Piglets were delivered 2 days prematurely. Six control piglets were fed enterally (E), whilst twelve animals were maintained on TPN. TPN piglets received the standard TPN solution plus the lipid emulsion as either ClinOleic(R) (C, n = 6) or Intralipid(R) (I, n = 6). Hepatic lipid content and the fatty acid composition of liver triacylglyercol (TAG) as well as hepatic lipase (HL) activity were determined. Lipoprotein lipase (LPL) activity was measured in the liver, muscle and adipose tissue. The plasma concentrations of choline, bilirubin, TAG and non-esterified fatty acids (NEFA) were also measured. RESULTS Liver lipid was significantly increased in piglets on TPN and the tissue fatty acid profiles reflected the lipid emulsion. HL and LPL activities were reduced in liver but LPL increased in adipose tissue during TPN. Plasma concentrations of choline, bilirubin, TAG and NEFA were similar across the treatments. CONCLUSIONS The results suggest fatty liver occurs in neonates receiving TPN and the source of the accumulated lipid appears to be the lipid emulsion used. The factors regulating lipase activity during TPN require further study. The piglet can be used as a model for neonatal TPN.