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 development has been reported. To avoid repeated blood collections for determination of long-chain polyunsaturated fatty acid status, the authors developed and evaluated a noninvasive method for analysis of buccal mucosal cell phospholipids. Methods: Oral mucosal cells were gently collected with a soft cotton swab, buccal cell lipids separated by thin-layer chromatography, and fatty acid methyl esters of the phospholipid fraction prepared. Subsequently, the fatty acid methyl esters were analyzed by high-resolution gas chromatography. Results: The method allowed reliable analysis from very small amounts of oral mucosal cells, and results were well reproducible. The intraindividual coefficients 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 collection. The method was applied in a clinical trial with preterm infants fed human breast milk or assigned by double-blind randomization to preterm formula with or without arachidonic and docosahexaenoic acid. Buccal mucosal cells were collected in infants less than 14 days of age and at the postconceptional ages of 52 weeks and 64 weeks. Dietary long-chain polyunsaturated fatty acids showed a lasting influence on buccal cell phospholipid composition. In the course of the study, arachidonic and docosahexaenoic acid decreased significantly in the nonenriched formula group, whereas stable or rising values were observed in the groups receiving breast milk or enriched formula. Conclusions: Buccal mucosal cell phospholipids are feasible for use as a noninvasive marker for long-chain polyunsaturated fatty acid status in preterm infants and yield reliable results. Dietary long-chain polyunsaturated fatty acids have a lasting influence on fatty acid composition of buccal cells in preterm babies.