Abstract 395: Changes in the HDL Lipidome With Regular Exercise: a Pilot Study

Background: Over 200 individual molecular lipid species have been found to reside on high-density lipoproteins (HDL). The effects of exercise on the HDL lipidome profile is unknown. Methods: We examined changes in the HDL lipidome after regular exercise in 20 individuals who completed a 20-week endurance exercise program as part of the HERITAGE Family Study. The 20 subjects were selected based on discordance for exercise-induced increases in mean HDL particle (HDL-P) size (10 high-responders, 10 non-responders). The abundance of 184 known individual lipid species was quantified in baseline and post-training HDL plasma samples by UPLC-QTOF-MS. HDL was isolated through gel filtration chromatography. Results: Seven lipid species, particularly classes of triacylglycerols, cholesteryl esters, phosphatidylcholines, and sphingomyelins, showed nominal (p<0.05) increases in abundance with exercise training, with fold changes ranging from 1.13 to 1.65 ( Figure 1 ). Three lipids showed differential responses to exercise between high- and non-responders of HDL-P size, including one lipid and metabolite each that showed an overall effect of training ( Figure 1 ). For example, the abundance of sphingomyelin d39:2 decreased by an average of 23% in the high-responders of HDL size to exercise, whereas abundance increased by 71% in the non-responders (p=0.004 for difference between groups). None of the exercise-induced changes in lipid levels were statistically significant after accounting for multiple testing. Discussion: This pilot study showed limited evidence of systematic remodeling of the HDL lipidome in response to regular endurance exercise. Future studies are needed with larger sample sizes, diverse populations, and differing exercise protocols to further examine how the molecular composition of HDL particles changes in response to exercise and potentially contributes to its atheroprotective functions.