Polyunsaturated fatty acids in cardiovascular diseases: uncertainty prevails.

In the late 1970s, a lower incidence of myocardial infarction and favorable hemostatic alterations were reported in Greenland Inuits. This observation prompted investigators worldwide to continue research on the role of a specific diet in this population and sparked an ongoing discussion about the potential use of polyunsaturated fatty acids (PUFAs) in the primary prevention of cardiovascular disease (VITAL), and the secondary prevention of primarily coronary artery disease (JELIS, REDUCE­IT, OMEMI). However, the current evidence to support the preventive value of PUFAs is inconsistent. Seminal clinical trials such as the GISSI­Prevenzione, JELIS, PREDIMED, or ASCEND differed in their approach to the assessment of cardiovascular effects of n-3 PUFAs and reported divergent results. The questions remain whether eicosapentaenoic acid is the only PUFA offering cardiovascular benefits, what is the importance of PUFA dosing, and, finally, who should receive n-3 PUFA treatment. This article discusses the latest insights into n-3 PUFA use in cardiovascular disease prevention.

Treatment with omega-3 polyunsaturated fatty acids does not improve endothelial function in patients with type 2 diabetes and very high cardiovascular risk: A randomized, double-blind, placebo-controlled study (Omega-FMD).

BACKGROUND AND AIMS: Numerous recent studies conducted in different clinical settings have focused on the benefits of omega-3 polyunsaturated fatty acids (n-3 PUFAs) in the prevention of cardiovascular diseases. There is limited evidence that patients with type 2 diabetes (T2D) and very high cardiovascular risk can also benefit from a high dose of n-3PUFAs, especially those on optimal medical therapy as recommended by the guidelines. The aim of the present study was to assess the impact of high-dose n-3 PUFA treatment on endothelial function in patients with T2D and established atherosclerotic cardiovascular disease (ASCVD). METHODS: We conducted a prospective randomized double-blind, placebo-controlled, 2-center study, in which endothelial function was measured using flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD). Serum fatty acids composition was measured by gas chromatography. All measurements were done at baseline and after 3 months of treatment with PUFAs at a dose of 2 g/d (n = 36) or placebo (n = 38). RESULTS: The majority of the study population was treated with optimal medical therapy. Despite significantly higher concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid in the n-3 PUFA group after 3-month treatment, we did not observe significant changes in endothelial function indices (FMD and NMD). However, in regression analysis, only baseline FMD was associated with EPA concentration before 3 months of n-3 PUFA treatment. CONCLUSIONS: Three months of high-dose n-3 PUFA treatment in very high-risk patients with ASCVD and T2D did not improve the endothelial function indices.

Treatment with high-dose n-3 PUFAs has no effect on platelet function, coagulation, metabolic status or inflammation in patients with atherosclerosis and type 2 diabetes.

BACKGROUND: Despite numerous studies on cardioprotective effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs), there is limited evidence for n-3 PUFA-mediated effects, especially at its higher dose, on cardiovascular risk in patients with type 2 diabetes (DM2) and established atherosclerosis. PURPOSE: To investigate the effect of daily treatment with a higher dose (2 g) of n-3 PUFAs on platelet function, coagulation parameters, fibrin clot properties, markers of systemic inflammation and metabolic status, in patients with atherosclerotic vascular disease and DM2 who receive optimal medical therapy. METHODS: We conducted a prospective, double-blind, placebo-controlled, randomized, double-center study, in which thrombin generation (plasma thrombogenic potential from automated thrombogram), fibrin clot properties (plasma fibrin clot permeability; lysis time), platelet aggregation (light transmission aggregometry with adenosine diphosphate and arachidonic acid used as agonists), HbA1c, insulin level, lipid profiles, leptin and adiponectin levels, as well as markers of systemic inflammation (i.e., hsCRP, IL-6, TNF-α, ICAM-1, VCAM-1, and myeloperoxidase) were determined at baseline and at 3 months after treatment with 2 g/day of n-3 PUFAs (n = 36) or placebo (n = 38). Moreover, we assessed serum fatty acids of the phospholipid fraction by gas chromatography both at baseline and at the end of the study. RESULTS: Majority of patients were treated with optimal medical therapy and achieved recommended treatment targets. Despite higher serum levels of eicosapentaenoic acid (EPA) (by 204%; p < 0.001) and docosahexaenoic acid (DHA) (by 62%; p < 0.0001) in n-3 PUFA group at the end of treatment no changes in platelet aggregation, thrombin generation, fibrin clot properties or markers of systemic inflammation were observed. No intergroup differences in the insulin, HbA1c and lipid levels were found at the end of the study. There was no change in adiponectin and leptin in interventional group, however leptin increased in control group (p = 0.01), therefore after study period leptin levels were lower in the interventional group (p = 0.01). Additionally, resolvin D1 did not differ between interventional and control group. CONCLUSIONS: In conclusion, our study demonstrated that in patients with long-standing, well-controlled DM2 and atherosclerotic disease the treatment with a high dose of n-3 PUFAs (namely, 1 g/day of EPA and 1 g/day of DHA for 3 months) does not improve coagulation, metabolic, and inflammatory status when measured with the specified tests. The study was registered in ClinicalTrials.gov; identifier: NCT02178501. Registration date: April 12, 2014.

Polyunsaturated omega-3 fatty acids reduce lipoprotein-associated phospholipase A(2) in patients with stable angina.

BACKGROUND AND AIMS: Increased consumption of omega-3 polyunsaturated fatty acids (PUFA) together with lifestyle measures and medications is recommended for the prevention of cardiovascular diseases. However, the exact mechanisms underlying observed benefits are not well defined. To this aim, we evaluated the effects of omega-3 PUFA in stable coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI) on lipoprotein associated phospholipase A2 (Lp-PLA2) mass and activity and their relation to oxidized low-density lipoproteins (oxy-LDL). METHODS AND RESULTS: In a prospective, double-blind, placebo-controlled, randomized study Lp-PLA2, oxy-LDL, myeloperoxidase and interleukin-6 were determined at baseline, 3-5 days and 30 days during administration of omega-3 PUFA 1 g/day (n = 30) or placebo (n = 24). Treatment with omega-3 PUFA resulted in reduction of Lp-PLA2 mass by 10.7%, activity by 9.3 (p = 0.026 for both) and oxy-LDL by 10.9% (p = 0.014) at 30 days, with no change in myeloperoxidase and interleukin-6. Compared with placebo, patients receiving omega-3 PUFA had lower Lp-PLA2 mass by 9.42%, activity by 9.2 (p = 0.041 for both) and oxy-LDL by 12.3% (p = 0.10) after one month, but not at 3-5 days. There were no correlations between Lp-PLA2 and both myeloperoxidase and oxy-LDL throughout the study. The multivariate model showed that only treatment with omega-3 PUFA and baseline myeloperoxidase levels were independent predictors of Lp-PLA2 mass changes at one month (R(2) = 0.37, P = 0.005). CONCLUSIONS: Administration of omega-3 PUFA can decrease Lp-PLA2 in patients with stable angina undergoing PCI. This novel effect may contribute to the benefits derived from omega-3 PUF.

Omega-3 polyunsaturated fatty acids increase plasma adiponectin to leptin ratio in stable coronary artery disease.

BACKGROUND: Growing evidence suggests a cardioprotective role of omega-3 polyunsaturated fatty acids (PUFA). However, the exact mechanisms underlying the effects of omega-3 PUFA in humans have not yet been fully clarified. PURPOSE: We sought to evaluate omega-3 PUFA-mediated effects on adipokines in patients with stable coronary artery disease (CAD) undergoing elective percutaneous coronary intervention (PCI). METHODS: We conducted a prospective, double-blind, placebo-controlled, randomized study, in which adiponectin, leptin and resistin were determined at baseline, 3-5 days and 30 days during administration of omega-3 PUFA 1 g/day (n=20) or placebo (n=28). RESULTS: As compared to controls administration of omega-3 PUFA resulted in increase of adiponectin by 13.4% (P<0.0001), reduction of leptin by 22% (P<0.0001) and increase of adiponectin to leptin (A/L) ratio by 45.5% (P<0.0001) at 30 days, but not at 3-5 days. Compared with placebo adiponectin was 12.7% higher (P=0.0042), leptin was 16.7% lower (P<0.0001) and A/L ratio was 33.3% higher (P<0.0001) in the omega-3 PUFA group at 30 days. Resistin decreased similarly in both groups after 1 month, without intergroup differences (P=0.32). The multivariate model showed that the independent predictors of changes in adiponectin at 1 month (P<0.001) were: omega-3 PUFA treatment, baseline platelet count, total cholesterol and those in leptin (P<0.0001) were: omega-3 PUFA treatment and waist circumference. Independent predictors of A/L ratio changes (P<0.0001) were: assigned treatment, current smoking and hyperlipidemia. CONCLUSIONS: In high risk stable coronary patients after PCI omega-3 PUFA supplementation improves adipokine profile in circulating blood. This might be a novel, favourable mechanism of omega-3 PUFA action.

Platelet activation and microvascular injury in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Dual antiplatelet therapy reduces the risk of thrombotic complications after primary percutaneous coronary intervention (PCI). AIM: To assess whether inhibition of platelet function attenuates microvascular damage in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: We studied 83 STEMI patients treated with primary PCI. Platelet aggregation was measured on admission (ADM) and 4 days later (D4) by light transmission aggregometry after stimulation with 0.5 mM of arachidonic acid and after stimulation with 5 and 20 µM of adenosine diphosphate (ADP) on treatment with dual antiplatelet therapy with aspirin and clopidogrel. Platelet-neutrophil aggregate (PNA) and platelet-monocyte aggregate (PMA) were analysed by flow cytometry. Contrast-enhanced magnetic resonance imaging was performed 2-4 days after STEMI to detect the area of perfusion defect at rest and to determine the size of microvascular obstruction. Microvascular obstruction was expressed as a percentage of infarct area. RESULTS: Perfusion defect at rest was found in 56 (67.5%) patients whereas microvascular obstruction in 63 (75.9%) patients. Patients with perfusion defect at rest had on admission a significantly higher level of both PMA (7.0 vs. 4.5%, p = 0.004) and PNA (4.1 vs. 2.2%, p = 0.016), however there were no significant differences at D4. Platelet aggregation after stimulation with 5 µM of ADP on ADM was correlated (r = 0.37, p = 0.004) with microvascular obstruction area. Moreover, the higher the concentration of PMA(ADM) (r = 0.31, p = 0.016), PNA(ADM) (r = 0.34, p = 0.006) and PM(AD4) (r = 0.35, p = 0.005) the larger the size of microvascular obstruction. Infarct size (ß = 0.43, 95% CI 0.19 to 0.67, p 〈 0.0001), TIMI < 3 after PCI (ß = -0.27, 95% CI -1.90 to -0.11, p = 0.015) and PMA(D4) (ß = 0.21, 95% CI 0.13 to 1.86, p = 0.032) independently influenced the size of microvascular obstruction (R2 = 0.60, p 〈 0.0001). CONCLUSIONS: Excessive platelet activation during reperfusion in STEMI patients despite dual antiplatelet therapy is associated with greater microvascular impairment.

Polyunsaturated omega-3 fatty acids improve responsiveness to clopidogrel after percutaneous coronary intervention in patients with cytochrome P450 2C19 loss-of-function polymorphism.

BACKGROUND: Antiplatelet properties of omega-3 polyunsaturated fatty acids (PUFA) have been demonstrated in patients with coronary artery disease (CAD). It is unknown whether omega-3 PUFA can enhance platelet inhibition on standard aspirin and clopidogrel treatment in the setting of CYP2C19 loss-of-function polymorphism. AIM: To investigate whether omega-3 PUFA are able to modify platelet responsiveness to clopidogrel therapy in patients with CYP2C19 loss-of-function polymorphism undergoing percutaneous coronary intervention (PCI). METHODS: 63 patients with stable CAD undergoing PCI (48 males, mean age 63.2 ± 9.6 years) were enrolled into an investigator- initiated, prospective, single-centre, double-blind, placebo-controlled, randomised study. Patients on standard dual antiplatelet therapy (aspirin 75 mg daily and clopidogrel 600 mg loading dose followed by 75 mg daily) were assigned to receive the addition of 1 g of omega-3 ethyl esters (n = 33) or placebo (n = 30) for 1 month. Platelet function was measured serially by light transmittance aggregometry in response to 5 and 20 µmol/L ADP at baseline, 12 h, 3-5 days and 30 days after randomisation. CYP2C19*2 was genotyped at baseline. RESULTS: No significant differences were found in baseline variables, including the frequency of CYP2C19 genetic variants. At least one loss-of-function variant of CYP2C19*2 was found in 19 (30.2%) patients. In patients with CYP2C19*1/*2 and *2/*2 variants, maximal platelet aggregation induced by 5 and 20 µmol/L ADP was reduced by 21.4% (p = 0.006) and 14.3% (p = 0.041), respectively, after 1 month of treatment with omega-3 PUFA as compared to placebo. The beneficial effect of omega-3 PUFA was demonstrated in carriers of CYP2C19 loss-of-function polymorphism, whereas no differences in platelet aggregation between the omega-3 PUFA and placebo groups were found in patients with the 1*/1* variant. CONCLUSIONS: The addition of omega-3 ethyl esters significantly potentiates platelet response to clopidogrel after PCI mostly in patients with CYP2C19 loss-of-function polymorphism.

Reduced thrombin formation and altered fibrin clot properties induced by polyunsaturated omega-3 fatty acids on top of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention (OMEGA-PCI clot).

OBJECTIVE: The goal of this study was to investigate whether omega-3 polyunsaturated fatty acids (n-3 PUFA) are able to alter plasma fibrin clot properties and reduce thrombin formation in stable coronary artery disease patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: In an investigator-initiated, prospective, double-blind, placebo-controlled, randomized study, patients undergoing PCI who received standard pharmacotherapy were assigned to the treatment with 1 g/day n-3 PUFA (n = 30) or placebo (n = 24) for 1 month. Plasma fibrin clot permeability (K(s)); lysis time (t(50%)); prothrombin fragment 1.2; and peak thrombin generation from automated thrombogram, 8-isoprostaglandin F(2α) (8-iso-PGF(2α), an oxidative stress marker), and C-reactive protein were determined at baseline, 3 to 5 days after randomization, and 30 days after randomization. At baseline, both treatment groups did not differ significantly. A 1-month treatment with n-3 PUFA compared with placebo was associated with 15.3% higher K(s), indicating larger pores in the fibrin network (P = 0.0005); 14.3% shorter t(50%), indicating increased susceptibility to fibrinolysis (P<0.0001); 33.8% lower prothrombin fragment 1.2 (P = 0.0013); 13.4% lower peak thrombin generation (P = 0.04); and 13.1% lower 8-iso-PGF(2α) (P = 0.009). Treatment with n-3 PUFA had no effect on fibrinogen and C-reactive protein. After 1 month of treatment, fibrinogen (r = -0.53, P<0.0001), treatment assignment (r = 0.29, P = 0.006) and 8-iso-PGF(2α) (r = -0.27, P = 0.015) were independently associated with clot permeability (P<0.0001, R(2) = 0.66). CONCLUSIONS: Adding n-3 PUFA to standard therapy in stable patients undergoing PCI significantly decreases thrombin formation and oxidative stress and favorably alters fibrin clot properties. These findings indicate novel antithrombotic effects induced by n-3 PUFA in humans.

Effects of polyunsaturated omega-3 fatty acids on responsiveness to dual antiplatelet therapy in patients undergoing percutaneous coronary intervention: the OMEGA-PCI (OMEGA-3 fatty acids after pci to modify responsiveness to dual antiplatelet therapy) study.

OBJECTIVES: The purpose of this study was to investigate whether omega-3 polyunsaturated fatty acids (PUFAs) are able to modify platelet responsiveness to dual antiplatelet therapy in stable coronary artery disease patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: Although previous studies have suggested antiplatelet properties of omega-3 polyunsaturated fatty acids, it is unknown whether they can enhance platelet inhibition on standard aspirin and clopidogrel treatment. METHODS: The OMEGA-PCI (OMEGA-3 Fatty Acids After PCI to Modify Responsiveness to Dual Antiplatelet Therapy) study was an investigator-initiated, prospective, single-center, double-blind, placebo-controlled, randomized study. Patients receiving standard dual antiplatelet therapy (aspirin 75 mg/day and clopidogrel 600 mg loading dose followed by 75 mg/day) were randomly assigned to receive the addition of 1 g of omega-3 ethyl esters (n = 33) or placebo (n = 30) for 1 month. Platelet function was measured serially by light transmission aggregometry (adenosine diphosphate and arachidonic acid [AA] were used as agonists) and assessment of the phosphorylation status of the vasodilator-stimulated phosphoprotein at baseline, 12 h, 3 to 5 days, and 30 days after randomization. RESULTS: The P2Y(12) reactivity index was significantly lower, by 22.2%, after 1 month of treatment with omega-3 polyunsaturated fatty acids compared with placebo when used in addition to dual antiplatelet therapy (p = 0.020). Maximal platelet aggregation induced by 5 and 20 micromol/l adenosine diphosphate was lower by 13.3% (p = 0.026) and 9.8% (p = 0.029), respectively, after 1 month of treatment with omega-3 polyunsaturated fatty acids compared with placebo. Platelet aggregation after AA stimulation was low and did not change significantly throughout the study. There were no cases of aspirin resistance during follow-up that was suggestive of good compliance with the medication. CONCLUSIONS: The addition of omega-3 ethyl esters to the combination of aspirin and clopidogrel significantly potentiates platelet response to clopidogrel after percutaneous coronary intervention.