Effects of administration of different intravenous lipid emulsions on plasma LP-X concentrations in the rat.

Abstract

Prolonged parenteral nutrition with lipid emulsions is essential to provide sufficient energy supply and to avoid essential fatty acid deficiency in preterm infants. However, chronic administration of lipid emulsions may lead to the development of pathological plasma lipid and LP-X concentrations. The aim of this study was to evaluate the relative importance of the phospholipid-triglyceride (PL-TG) ratio and the source of phospholipid in lipid emulsions, with respect to plasma lipid and LP-X levels. Rats were infused for 9 days with IV lipid emulsion containing 10% (IL-10) or 20% (IL-20) egg lecithin or Lipofundin containing 20% soya lecithin (LF), with PL-TG ratios of .12, .06, and 0.75, respectively. LF significantly increased plasma triglyceride concentration (p < .01), whereas the rise in cholesterol levels observed with all emulsions was primarily caused by the increase in low-density lipoprotein cholesterol concentrations. The plasma phospholipid concentration was increased most by IL-10 (p < .005). There was a strong correlation between the PL-TG ratio of emulsions and the developing plasma phospholipid and LP-X concentrations (r2 = .91 and .96, respectively), despite the different origin of phospholipids in the emulsions, suggesting that it is the PL-TG ratio, rather than the source of phospholipids in lipid emulsions that primarily influences developing plasma lipid and LP-X concentrations. These results indicate that the administration of lipid emulsions with lower PL-TG ratios should be considered, to avoid the development of pathological plasma lipoprotein concentrations.