(P27-064-25) Characterization of Oxylipins in Human Milk Extracellular Vesicles

Objectives: Extracellular vesicles (EVs) in human milk are bioavailable and influence physiologic pathways that may contribute to newborn growth and development. There is interest in the oxylipin content of EVs as it may contribute to the bioavailability of EVs. This research aims to characterize the oxylipin content of human milk EVs.

Methods: EVs were isolated from human milk (n = 20) using centrifugation in combination with a precipitation reagent. Solvent extracts from human milk and human milk EVs were purified by solid phase extraction and analyzed for 34 oxylipins with deuterated and external standards using QqQ LC-MS. The relative content of oxylipins were normalized to the sample total protein content.

Results: There was a higher relative abundance of n-6-derived oxylipins (93-97%) than n-3-derived oxylipins (2.9-6.3%) in both EVs and whole human milk. The relative content of omega-6-derived oxylipins was significantly higher (p < 0.0001) in EVs (97.1 +/- 1.8%) than in human milk (93.7 +/- 5.0%) , and omega-3-derived oxylipins were significantly lower (p < 0.0001) in EVs (2.9 +/- 1.8%) than in human milk (6.3 +/- 5.0%). Human milk had higher amounts (p-values  < 0.0003) of AA-, DHA-, and EPA-derived oxylipins (12%, 5.43%, 0.89%, respectively) than EVs (8.74%, 2.71%, 0.18%, respectively), and LA-derived oxylipins were elevated (p < 0.001) in EVs (88.37 +/- 3.4%) as compared with human milk (81.69 +/- 8.3%).

Conclusions: Oxylipins present in human milk EVs and whole human milk may be critical to the bioavailability and passage of dietary EVs across physiologic barriers. Dietary alteration of fatty acid intake may impact the oxylipins composition of EVs and the bioavailability of human milk EVs in newborns.

Funding Sources: USDA