Pediatr Res 1991 Jan;29(1):56-9

Generation of free radicals in lipid emulsion used in parenteral nutrition

Pitkanen O, Hallman M, Andersson S
Children's Hospital, Helsinki, Finland.

Abstract
Lipid emulsions used in parenteral nutrition are prone to peroxidation that may
be an important feature of oxygen-associated tissue damage. Incubation of lipid
emulsion [Intralipid (IL)] with H2O2 and FeCl2 increased lipid peroxidation,
measurable as increased production of pentane, from 0.39 +/- 0.33 to 0.99 +/-
0.18 microM (p less than 0.0001). Malondialdehyde was increased from 0.010 +/-
0.005 mM to 0.380 +/- 0.025 mM (p less than 0.001). Superoxide dismutase and
catalase (each 100 U/mL) or vitamin C (10 mM) inhibited pentane and
malondialdehyde production (p less than 0.0001). Incubation of human
erythrocytes in the presence of FeCl2 caused 11.0 +/- 3.2% hemolysis (control
0.95 +/- 0.14%). Addition of 0.44% IL increased hemolysis to 66.5 +/- 3.4%,
whereas further addition of vitamin E or C significantly inhibited hemolysis to
16.4 +/- 8.1 and 38.9 +/- 7.1%, respectively (p less than 0.0001). IL was
administered i.v. to eight preterm infants. It increased 3- to 28-fold (p less
than 0.001) the amount of pentane in expired breath. Partly, this increase was
due to pentane dissolved in IL as a result of lipid peroxidation during storage.
After discontinuing IL infusion, the elimination of pentane was nonexponential,
consisting of a rapid and a slow component. According to our results, IL
undergoes peroxidation causing free-radical-dependent damage to human cells. We
propose that the adverse effects of parenteral IL are partially caused by free
oxygen radicals generated by lipid peroxidation