Effect of liposomal content of lipid emulsions on plasma lipid concentrations in low birth weight infants receiving parenteral nutrition.

We studied the effects of phospholipid liposomes present in intravenously administered lipid emulsions on plasma lipid levels in preterm infants given 10% and 20% lipid emulsions. Twenty premature infants (birth weight 1454 +/- 54 gm) on a parenteral nutrition regimen received up to 4 gm triglycerides per kilogram per day in a 20% lipid emulsion for 2 weeks, and then received the 10% emulsion at 2 gm triglycerides per kilogram per day, which delivered the same total phospholipid load but twice the amount of liposomes. Triglyceride, total cholesterol, and phospholipid concentrations increased significantly when the infants were given 2 gm triglycerides per kilogram per day in the 10% emulsion rather than 4 gm/kg per day in the 20% emulsion (44 +/- 4 to 57 +/- 5 mg/dl, 134 +/- 6 to 162 +/- 9 mg/dl, and 204 +/- 8 to 251 +/- 10 mg/dl, respectively). Lipoprotein analysis indicated the presence of lipoprotein X-like particles in the low-density lipoprotein fraction and an increase of the intermediate-density lipoprotein fraction in infants who received the 10% emulsion. The presence of excess phospholipids in the 10% emulsion was associated with greater plasma lipid alterations. Therefore the use of 20% rather than 10% emulsion allows for more efficient triglyceride clearance, even at a higher triglyceride intake. Administration of emulsions that are relatively poor in phospholipid liposomes may allow delivery of > 2 gm triglycerides per kilogram per day to low birth weight infants.