Plasma fatty acids in chronic kidney disease: nervonic acid predicts mortality.

Although the value of red blood cell fatty acids (FAs) in estimating risk for acute coronary syndrome in the general population is evident, the value of FAs in chronic kidney disease (CKD) is unknown. Here, we provide a pilot analysis in a spectrum of CKD patients. Plasma samples were obtained from 20 incident dialysis patients (CKD stage 5), matched with samples from 10 CKD stage 3-4 patients, and 10 control subjects. Whole plasma FAs were measured using gas chromatography. Whereas neither linoleic acid nor arachidonate acid were altered in CKD, metabolic intermediates of arachidonate synthesis (γ-linolenate and dihomo γ-linolenate) were reduced in CKD. Demming (orthogonal) correlation of FA abundance with estimated GFR identified several saturated and unsaturated FAs in addition to the intermediates; again, neither linoleate nor arachidonate were related. Follow-up data within the CKD stage 5 patients revealed that nervonic acid, a component of membrane sphingolipids and phosphatidylethanolamines, was a significant predictor of all-cause mortality; the age-adjusted relative risk for a 0.15% change is 2.1 (1.4, 3.7; 95% CI; P = .0008). These findings support the exploration of FAs in larger studies for validation of the role FAs in cardiovascular risk and mortality in CKD.