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).

BACKGROUND: Patients with peripheral artery disease (PAD) experience significant morbidity and mortality. The OMEGA-PAD I Trial, a randomized, double-blinded, placebo-controlled trial, addressed the hypothesis that short-duration, high-dose n-3 polyunsaturated fatty acids (n-3 PUFA) oral supplementation improves endothelial function and inflammation in PAD. METHODS AND RESULTS: Eighty patients with stable claudication received 4.4 g of fish oil or placebo for 1 month. The primary end point was endothelial function as measured by brachial artery flow-mediated vasodilation. Secondary end points included biomarkers of inflammation, n-3 polyunsaturated fatty acids metabolome changes, lipid profile, and walking impairment questionnaires. Although there was a significant increase in FMD in the fish oil group following treatment (0.7±1.8% increase from baseline, P=0.04), this response was not different then the placebo group (0.6±2.5% increase from baseline, P=0.18; between-group P=0.86) leading to a negative finding for the primary endpoint. There was, however, a significant reduction in triglycerides (fish oil: -34±46 mg/dL, P<0.001; placebo -10±43 mg/dL, P=0.20; between-group differential P-value: 0.02), and an increase in the omega-3 index of 4±1% (P<0.001) in the fish oil group (placebo 0.1±0.9%, P=0.49; between-group P<0.0001). We observed a significant increase in the production of pathway markers of specialized pro-resolving mediators generated from n-3 polyunsaturated fatty acids in the fish oil group. CONCLUSIONS: High-dose, short-duration fish oil supplementation did not lead to a different response in the primary end point of endothelial function between the treatment and placebo group, but improved serum triglycerides and increased the production of downstream n-3 polyunsaturated fatty acids-derived products and mediators in patients with PAD. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01310270.

Clinical correlates of red blood cell omega-3 fatty acid content in male veterans with peripheral arterial disease.

OBJECTIVE: Despite available medical therapies, patients with peripheral arterial disease (PAD) remain at high risk for cardiovascular events. The n-3 polyunsaturated fatty acids (PUFA), derived from marine sources, have been shown to improve cardiovascular mortality. The Omega-3 Index (O3I), a proportion of the n-3 PUFA eicosapentaenoic acid and docosahexaenoic acid in the red blood cell membrane, correlates with cardiovascular risk. Previous investigations have found that n-3 PUFA supplementation, fish consumption, older age, and smoking history affect the O3I in different patient populations, although similar correlations have never been explored in PAD. We hypothesized that in our PAD cohort, blood content of omega-3 fatty acids would directly and positively correlate with a history of fish oil supplementation and older age and inversely correlate with a smoking history and obesity. METHODS: This cross-sectional study included 111 patients who had an ankle-brachial index of <0.9 associated with claudication symptoms. We used linear regression to determine the association between clinical factors and the O3I. RESULTS: The mean age of the cohort was 69 ± 8 years; 37% had diabetes mellitus (hemoglobin A1c, 7% ± 1%), and 94% reported current smoking or a history of smoking. The mean O3I was 5% ± 2%. In multivariate linear regression analysis, the O3I was associated with older age, increasing body mass index, and a history of smoking and fish oil intake. CONCLUSIONS: This is the first report of the relation between blood content of omega-3 fatty acids and clinical factors in a PAD population. In patients with PAD, older age, elevated body mass index, and prior fish oil supplementation predicted a higher O3I. A history of smoking correlated with a lower O3I. These results demonstrate that the O3I is a reliable measure of dietary n-3 PUFA intake and that clinical factors related to the O3I in PAD are similar to those observed in other populations.

n-3 Polyunsaturated fatty acids supplementation in peripheral artery disease: the OMEGA-PAD trial.

Despite current consensus guidelines recommending intensive cardiovascular risk factor management for peripheral artery disease (PAD), patients suffering from PAD continue to experience significant morbidity and mortality. This excess morbid burden is at least partially related to impaired vascular function and systemic inflammation. Interventions bridging this gap are critical. Dietary supplementation of n-3 polyunsaturated fatty acids (n-3 PUFA) has been shown to improve endothelial function and reduce inflammation in different cohorts, as well as to decrease cardiovascular events in secondary prevention trials in patients with coronary artery disease. Their effects in the PAD population are, however, less well understood. The OMEGA-PAD trial is a double-blinded, randomized, placebo-controlled trial that examines the impact of a high-dose, short-duration dietary oral supplementation of n-3 PUFA on vascular function and inflammation in patients with established PAD. The purpose of this article is to provide a detailed description of the design and methods of the OMEGA-PAD trial, and a summary of baseline characteristics of the cohort.

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

OBJECTIVE: The n-3 polyunsaturated fatty acids 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 proinflammatory state. We hypothesized that the n-3 polyunsaturated fatty acids 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, interleukin-6, and tumor-necrosis-factor-α) and endothelial function (brachial artery flow mediated dilation). RESULTS: 64 subjects (61 claudicants and three 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, ankle-brachial index, and high-density lipoprotein (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 ankle-brachial index. 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.

Differences in nutrition status by body mass index in patients with peripheral artery disease.

Peripheral Arterial Disease (PAD) is most prevalent in the elderly and associated with increased cardio vascular disease (CVD) morbidity and mortality. Treatment focuses on improving functional capacity and reducing CVD risk factors. To date, little is understood about dietary habits and weight in this patient population. Nutritional and weight recommendations are based on heart health, and little is known about the unique needs of elderly PAD patients with multiple comorbidities. This prospective study compared 1) the dietary intake of nonobese PAD patients in comparison with those who were obese and; 2) dietary intake of those patients with the Estimated Average Requirement (EAR) based on age, gender and BMI. Nutritional intake was assessed with the Block 98 Food Frequency Questionnaire. Body mass index (BMI) was calculated in accordance with the National Heart, Lung, and Blood Institute (NHLBI) guidelines.The study population was divided into obese (BMI ≥ 30) and nonobese (NO) groups. Comparisons between groups were performed using the Mann-Whitney U test for continuous variables and the Chi-square test for ordinal variables. All tests were two-tailed and P < 0.05 was considered significant. The Estimated Average Requirement (EAR) cut-point method was used to compare nutritional variables with Dietary Reference Intakes (DRI). The study population included 189 NO (BMI < 30) and 111 obese (BMI > 30) individuals. Obese participants reported greater intake of foods containing cholesterol and trans-fatty acids and more frequent intake of B vitamins in comparison with the NO BMI group. Additionally, the nutrient intake of all participants by age, gender and BMI was lower than the EAR for magnesium, folate, and Vitamin E. These results suggest that the nutritional intake of PAD patients differs based on gender and BMI. Additionally, EAR was lower for specific nutrients than recommended. Further investigation is needed to examine the association between nutritional intake and nutrition-related deficits.