Association between n-3 polyunsaturated fatty acid content of red blood cells and inflammatory biomarkers in patients with peripheral artery disease

Abstract

Objective The n-3 polyunsaturated fatty acids (PUFA) are dietary components derived from fish oil with beneficial cardiovascular effects that may relate in part to anti-inflammatory properties. Peripheral artery disease (PAD) is characterized by a marked pro-inflammatory state. We hypothesized that the n-3 PUFA content of red blood cells (omega-3 index) would be correlated with biomarkers of inflammation and vascular function in a PAD cohort. Methods This was a cross-sectional study of subjects who presented to an outpatient vascular surgery clinic for evaluation of PAD. We used linear regression to evaluate the independent association between the omega-3 index, inflammatory biomarkers [C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), and tumor-necrosis-factor-α (TNF-α)] and endothelial function (brachial artery flow mediated dilation [FMD]). Results 64 subjects (61 claudicants and 3 with critical limb ischemia) were recruited for the study. The mean CRP level was 5.0 ± 5.0 mg/L and the mean omega-3 index was 5.0% ± 1.8%. In an unadjusted model, the omega-3 index was negatively associated with CRP (38% increase in CRP for one standard deviation decrease in the omega-3 index; P=.007) which remained significant after adjustment for age, body-mass index, smoking, the ABI and HDL (33%; P=.04). There was also evidence for independent associations between the omega-3 index and IL-6 (P=.001). There were no significant associations between the omega-3 index and vascular function tests. Conclusions In a cohort of patients with PAD, the omega-3 index was inversely associated with biomarkers of inflammation even after adjustment for covariates including the ABI. Because patients with PAD have a high inflammatory burden, further studies should be conducted to determine if manipulation of omega-3 index via dietary changes or fish oil supplementation could improve inflammation and symptoms in these patients.

Importance of maintaining a low omega–6/omega–3 ratio for reducing inflammation

“…In a cross-sectional study, the omega-3 index (omega-3 PUFA content of red blood cells) was inversely related to inflammation (C reactive protein (CRP) and IL-6) in patients with peripheral arterial disease (PAD) 20. Those with a mean omega-3 index of 6.8% had the lowest log-CRP values (0.6 mg/L) compared with those with omega-3 indexes of 4.5% and 3.7% (1.4 mg/L for both).…”

Posttraumatic Stress Disorder Is Associated With Worse Endothelial Function Among Veterans

“…Endothelial function was measured using brachial artery endothelium-dependent FMD in the Vascular Integrated Physiology and Experimental Therapeutics (VIPERx) Laboratory at UCSF, according to current guidelines and standards previously described by our group. [17][18][19][20][21][22] Under fasting conditions, including abstention from nicotine and caffeine, participants acclimated in the laboratory for 10 minutes in a supine position in a temperature-controlled, low-lit room. A 5-cm tourniquet blood pressure cuff was placed on the upper arm distal to the insertion of the deltoid.…”

Short‐Term, High‐Dose Fish Oil Supplementation Increases the Production of Omega‐3 Fatty Acid–Derived Mediators in Patients With Peripheral Artery Disease (the OMEGA‐PAD I Trial)

“…Very few studies have been conducted in symptomatic PAD patients, who exhibit the most pronounced inflammatory phenotype among all of the clinical subtypes of atherosclerosis. Our group recently demonstrated that the omega‐3 index, a measure of n‐3 PUFA content in red blood cells, is inversely related to inflammation in patients with PAD, and others have shown that n‐3 PUFA supplementation can improve endothelial function and arterial stiffness …”