Noninvasive assessment of essential fatty acid status in preterm infants by buccal mucosal cell phospholipid analysis

Background: The dietary supply of long-chain polyunsaturated fatty acids is receiving increased attention since a linkage to infant growth and develop ment has been reported. To avoid repeated blood collections for determinati on of long-chain polyunsaturated fatty acid status, the authors developed a nd evaluated a noninvasive method for analysis of buccal mucosal cell phosp holipids. Methods: Oral mucosal cells were gently collected with a soft cotton swab, buccal cell lipids separated by thin-layer chromatography, and fatty acid m ethyl esters of the phospholipid fraction prepared. Subsequently, the fatty acid methyl eaters were analyzed by high-resolution gas chromatography. Results: The method allowed reliable analysis from very small amounts of or al mucosal cells, and results were well reproducible. The intraindividual c oefficients of variation in four samples of three subjects were less than 5 % for both arachidonic and docosahexaenoic acid. Fatty acid composition was not altered by consumption of milk formula before and after sample collect ion. The method was applied in a clinical trial with preterm infants fed hu man breast milk or assigned by double-blind randomization to preterm formul a with or without arachidonic and docosahexaenoic acid. Buccal mucosal cell s were collected in infants less than 14 days of age and at the postconcept ional ages of 52 weeks and 64 weeks. Dietary long-chain polyunsaturated fat ty acids showed a lasting influence on buccal cell phospholipid composition . In the course of the study, arachidonic and docosahexaenoic acid decrease d significantly in the nonenriched formula group, whereas stable or rising values were observed in the groups receiving breast milk or enriched formul a. Conclusions: Buccal mucosal cell phospholipids are feasible for use as a no ninvasive marker for long-chain polyunsaturated fatty acid status in preter m infants and yield reliable results. Dietary long-chain polyunsaturated fa tty acids have a lasting influence on fatty acid composition of buccal cell s in preterm babies.