Fibroblast fatty acids in cystic fibrosis

The possibility of an inborn error of linoleic acid metabolism or of linoleic acid content in cystic fibrosis (CF) was investigated using fibroblasts from children with CF and from control children. Three experiments were done in which fibroblasts were cultured with 1-14C linoleic acid in media containing: (experiment 1) regular fetal calf serum (FCS); (experiment 2) linoleic acid-supplemented FCS; and (experiment 3) delipidated FCS supplemented with linoleic acid. Radioactivity from 1-14C linoleic acid incorporated into the total lipids was quantitatively similar in CF fibroblasts compared to controls in all three experiments. In the first two experiments the radioactivity incorporated into the phospholipid fraction was slightly higher in CF fibroblasts than in controls, whereas radioactivity incorporated into the neutral lipid fraction of CF fibroblasts was slightly lower than in controls. These differences were not found in experiment 3. No differences in linoleic and arachidonic acid composition were found between CF and control fibroblasts in any of the three experiments. The inability to find major alterations in linoleic acid metabolism or content in fibroblasts from children with CF makes a primary metabolic defect in linoleic acid metabolism unlikely.