Dietary Omega-3 Polyunsaturated Fatty Acids Alter the Fatty Acid Composition of Hepatic and Plasma Bioactive Lipids in C57BL/6 Mice : A Lipidomic Approach

Background Omega (n)-3 polyunsaturated fatty acids (PUFA) are converted to bioactive lipid components that are important mediators in metabolic and physiological pathways; however, which bioactive compounds are metabolically active, and their mechanisms of action are still not clear. We investigated using lipidomic techniques, the effects of diets high in n-3 PUFA on the fatty acid composition of various bioactive lipids in plasma and liver. Methodology and Principal Findings Female C57BL/6 mice were fed semi-purified diets (20% w/w fat) containing varying amounts of n-3 PUFA before mating, during gestation and lactation, and until weaning. Male offspring were continued on their mothers’ diets for 16 weeks. Hepatic and plasma lipids were extracted in the presence of non-naturally occurring internal standards, and tandem electrospray ionization mass spectrometry methods were used to measure the fatty acyl compositions. There was no significant difference in total concentrations of phospholipids in both groups. However, there was a significantly higher concentration of eicosapentaenoic acid containing phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and cholesteryl esters (CE) (p < 0.01) in the high n-3 PUFA group compared to the low n-3 PUFA group in both liver and plasma. Plasma and liver from the high n-3 PUFA group also had a higher concentration of free n-3 PUFA (p < 0.05). There were no significant differences in plasma concentrations of different fatty acyl species of phosphatidylethanolamine, triglycerides, sphingomyelin and ceramides. Conclusions/Significance Our findings reveal for the first time that a diet high in n-3 PUFA caused enrichment of n-3 PUFA in PC, LPC, CE and free fatty acids in the plasma and liver of C57BL/6 mice. PC, LPC, and unesterified free n-3 PUFA are important bioactive lipids, thus altering their fatty acyl composition will have important metabolic and physiological roles

The association between sleep patterns and obesity in older adults

BACKGROUND: Reduced sleep duration has been increasingly reported to predict obesity. However, timing and regularity of sleep may also be important. In this study, the cross-sectional association between objectively measured sleep patterns and obesity was assessed in two large cohorts of older individuals. METHODS: Wrist actigraphy was performed in 3053 men (mean age: 76.4 years) participating in the Osteoporotic Fractures in Men Study (MrOS) and 2985 women (mean age: 83.5 years) participating in the Study of Osteoporotic Fractures (SOF). Timing and regularity of sleep patterns were assessed across nights, as well as daytime napping. RESULTS: Greater night-to-night variability in sleep duration and daytime napping were associated with obesity independent of mean nocturnal sleep duration in both men and women. Each 1 hour increase in the variability of nocturnal sleep duration increased the odds of obesity 1.63-fold (95% CI [1.31-2.02]) among men and 1.22-fold (95% CI [1.01-1.47]) among women. Each 1 hour increase in napping increased the odds of obesity 1.23-fold (95%CI [1.12-1.37]) in men and 1.29-fold (95%CI [1.17-1.41]) in women. In contrast, associations between later sleep timing and night-to-night variability in sleep timing with obesity were less consistent. CONCLUSIONS: In both older men and women, variability in nightly sleep duration and daytime napping were associated with obesity independent of mean sleep duration. These findings suggest that characteristics of sleep beyond mean sleep duration may play a role in weight homeostasis, highlighting the complex relationship between sleep and metabolism