Muscle Loss Associated Changes of Oxylipin Signatures During Biological Aging: An Exploratory Study From the PROOF Cohort.

Characterizations of the multiple mechanisms determining biological aging are required to better understand the etiology and identify early biomarkers of sarcopenia. Oxylipins refer to a large family of signaling lipids involved in the regulation of various biological processes that become dysregulated during aging. To investigate whether comprehensive oxylipin profiling could provide an integrated and fine characterization of the early phases of sarcopenia, we performed a quantitative targeted metabolomics of oxylipins in plasma of 81-year-old subjects from the PROOF cohort with decreased (n = 12), stable (n = 16), or increased appendicular muscle mass (n = 14). Multivariate and univariate analyses identified significant and concordant changes of oxylipin profiles according to the muscle status. Of note, 90% of the most discriminant oxylipins were derived from EPA and DHA and were increased in the sarcopenic subjects. The oxylipins signatures of sarcopenic subjects revealed subtle activation of inflammatory resolution pathways, coagulation processes, and oxidative stress as well as the inhibition of angiogenesis. Heat maps highlighted relationships between oxylipins and the cardiometabolic health parameters which were mainly lost in sarcopenic subjects. This exploratory study supports that targeted metabolomics of oxylipins could provide relevant and subtle characterization of early disturbances associated with muscle loss during aging.

A diet rich in omega-3 fatty acids enhances expression of soluble epoxide hydrolase in murine brain.

Several studies suggest that intake of omega-3 polyunsaturated fatty acids (n3-PUFA) beneficially influences cognitive function. However, effects on the adult brain are not clear. Little is known about the impact of dietary intervention on the fatty acid profile in adult brain, the modulation in the expression of enzymes involved in fatty acid biosynthesis and metabolism as well as changes in resulting oxylipins. These questions were addressed in the present study in two independent n3-PUFA feeding experiments in mice. Supplementation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA, 1% each in the diet) for 30days to adult NMRI and C57BL/6 mice led to a distinct shift in the brain PUFA pattern. While n3-PUFAs EPA, n3 docosapentaenoic acid and DHA were elevated, many n6-PUFAs were significantly decreased (except, e.g. C20:3 n6 which was increased). This shift in PUFAs was accompanied by immense differences in concentrations of oxidative metabolites derived from enzymatic conversion of PUFAs, esp. arachidonic acid whose products were uniformly decreased, and a modulation in the activity and expression pattern of delta-5 and delta-6 desaturases. In both mouse strains a remarkable increase in the soluble epoxide hydrolase (sEH) activity (decreased epoxy-FA concentrations and epoxy-FA to dihydroxy-FA-ratios) as well as sEH expression was observed. Taking the high biological activity of epoxy-FA, e.g. on blood flow and nociceptive signaling into account, this finding might be of relevance for the effects of n3-PUFAs in neurodegenerative diseases. On any account, our study suggests a new distinct regulation of brain PUFA and oxylipin pattern by supplementation of n3-PUFAs to adult rodents.