Eicosapentaenoic acid prevents arterial calcification in klotho mutant mice.

BACKGROUND: The klotho gene was identified as an "aging-suppressor" gene that accelerates arterial calcification when disrupted. Serum and vascular klotho levels are reduced in patients with chronic kidney disease, and the reduced levels are associated with arterial calcification. Intake of eicosapentaenoic acid (EPA), an n-3 fatty acid, reduces the risk of fatal coronary artery disease. However, the effects of EPA on arterial calcification have not been fully elucidated. The aim of this study was to determine the effect of EPA on arterial calcification in klotho mutant mice. METHODS AND RESULTS: Four-week-old klotho mutant mice and wild-type (WT) mice were given a diet containing 5% EPA (EPA food, klotho and WT: n = 12, each) or not containing EPA (control food, klotho and WT: n = 12, each) for 4 weeks. Calcium volume scores of thoracic and abdominal aortas assessed by computed tomography were significantly elevated in klotho mice after 4 weeks of control food, but they were not elevated in klotho mice after EPA food or in WT mice. Serum levels of EPA and resolvin E1, an active metabolite of EPA, in EPA food-fed mice were significantly increased compared to those in control food-fed mice. An oxidative stress PCR array followed by quantitative PCR revealed that NADPH oxidase-4 (NOX4), an enzyme that generates superoxide, gene expression was up-regulated in arterial smooth muscle cells (SMCs) of klotho mice. Activity of NOX was also significantly higher in SMCs of klotho mice than in those of WT mice. EPA decreased expression levels of the NOX4 gene and NOX activity. GPR120, a receptor of n-3 fatty acids, gene knockdown by siRNA canceled effects of EPA on NOX4 gene expression and NOX activity in arterial SMCs of klotho mice. CONCLUSIONS: EPA prevents arterial calcification together with reduction of NOX gene expression and activity via GPR120 in klotho mutant mice.

Postprandial hyperlipidemia as a potential residual risk factor.

Statin therapy targeting reduction of low-density lipoprotein cholesterol (LDL-C) decreases the risk of coronary heart disease (CHD) and all-cause mortality. However, a substantial number of cases of CHD are not prevented and residual risk factors remain unsettled. A high triglyceride (TG) level is considered to be an important and residual risk factor. Postprandial hyperlipidemia is a condition in which TG-rich chylomicron remnants are increased during the postprandial period and hypertriglycedemia is protracted. Postprandial hyperlipidemia evokes atherogenesis during the postprandial period. Several prospective studies have revealed that nonfasting serum TG levels predict the incidence of CHD. Values of TG, remnant lipoprotein cholesterol, and remnant lipoprotein TG after fat loading were significantly higher in diabetes patients with insulin resistance than in diabetes patients without insulin resistance. Endothelial dysfunction is an initial process of atherogenesis and it contributes to the pathogenesis of CHD. Postprandial hyperlipidemia (postprandial hypertriglyceridemia) is involved in the production of proinflammatory cytokines, recruitment of neutrophils, and generation of oxidative stress, resulting in endothelial dysfunction in healthy subjects, hypertriglyceridemic patients, or type 2 diabetic patients. Effective treatment has not been established till date. Ezetimibe or omega-3 fatty acids significantly decrease postprandial TG elevation and postprandial endothelial dysfunction. Ezetimibe or omega-3 fatty acids added to statin therapy reduce serum TG levels and result in good outcomes in patients with CHD. In conclusion, postprandial hyperlipidemia is an important and residual risk factor especially in patients with insulin resistance syndrome (metabolic syndrome) and diabetes mellitus. Further studies are needed to establish effective treatment.

Omega-3 fatty acids improve postprandial lipemia and associated endothelial dysfunction in healthy individuals - a randomized cross-over trial.

BACKGROUND: Postprandial elevation of triglycerides impairs endothelial function and contributes to the development of atherosclerosis. We investigated the effects of omega-3 fatty acids on postprandial endothelial function and lipid profiles. METHODS: Healthy volunteers [10] were given supplementation at 4g/day omega-3 fatty acids (or were not treated) for 4 weeks in a randomised crossover study. Postprandial levels of various lipids were monitored and endothelial function assessed by brachial artery flow-mediated dilation during fasting and after a standard cookie test. RESULTS: Omega-3 fatty acids reduced postprandial endothelial dysfunction compared with the control diet (flow-mediated dilation at 4h=-0.5±1.2 vs. -2.0±1.6%, P=0.03). Postprandial levels of triglycerides, apolipoprotein B-48, and remnant lipoprotein-cholesterol increased in untreated subjects, peaked at 2-4h, and returned to baseline at 8h, whereas low-density lipoprotein-cholesterol levels did not change. Supplementation with omega-3 fatty acids significantly suppressed postprandial elevation of triglycerides (incremental area under the curve=220±209 vs. 374±216mg/h/dL, P=0.04) and remnant lipoprotein-cholesterol (incremental area under the curve=21.7±13.8 vs. 13.3±12.9mg/h/dL, P=0.04). Supplementation with omega-3 fatty acids significantly suppressed the increase in triglyceride content in chylomicrons as well as in very-low-density lipoproteins from baseline to 4h after the cookie test. CONCLUSION: Omega-3 fatty acids significantly decreased postprandial triglyceride elevation and postprandial endothelial dysfunction, suggesting that omega-3 fatty acids may have vascular protective effects in postprandial state.

Spasm provocation tests performed under medical therapy: a new approach for treating patients with refractory coronary spastic angina on emergency admission.

Objective There are no objective methods for evaluating the severity of vasospasms in patients with refractory coronary spastic angina (R-CSA) under adequate medical therapy. We examined whether spasm provocation tests performed under adequate medication are useful for evaluating the severity of disease in R-CSA patients on emergency admission. Methods and Results We performed spasm provocation tests before and after the administration of medical therapy in eight R-CSA patients, including one ventricular fibrillation survivor (VF-S) and seven patients with unstable angina (UAP) on emergency readmission. We also performed these tests only after medical therapy on urgent admission in four R-CSA patients, including two patients with UAP, one patient with VF-S and one patient with acute coronary syndrome. All 12 R-CSA patients had been medicated with ≥ 2 vasodilator drugs. Positive coronary spasms were defined as >99% transient narrowing. The coronary artery spasms disappeared in three patients under medication, and mitigation of vasospasticity was observed in three patients. In these six cases we continued the same medications. Meanwhile in two patients, we recommended a consultation for psychosomatic medicine. In contrast, the remaining six R-CSA patients exhibited higher levels of vasospasticity, irrespective of the administration of aggressive medical therapy, in which the doses of vasoactive drugs were increased in order to suppress coronary artery spasms. Conclusion In some R-CSA patients on emergency admission, performing spasm provocation tests under medical therapy is useful for determining the subsequent treatment strategy. Therefore, this test may become a new tool in the treatment of R-CSA.

Add-on ezetimibe reduces small dense low-density lipoprotein cholesterol levels without affecting absorption of eicosapentaenoic acid in patients with coronary artery disease: a pilot study.

BACKGROUND: Residual risk of cardiovascular disease from increased small dense low-density lipoprotein (sdLDL)-cholesterol levels and low n-3 polyunsaturated fatty acid (PUFA) levels is a considerable therapeutic issue. The purpose of this study was to evaluate the effect of ezetimibe as an add-on to statins and supplemental eicosapentaenoic acid (EPA) on sdLDL cholesterol and absorption of EPA in patients with coronary artery disease. METHODS: The study population consisted of ten male patients who were concurrently receiving statins and EPA 1,800 mg/day. Serum lipids and PUFAs, including EPA and arachidonic acid, were measured in blood samples collected before ezetimibe (baseline), 4 weeks after starting 10-mg/day ezetimibe, and 4 weeks after discontinuing ezetimibe. RESULTS: Ezetimibe significantly decreased sdLDL-cholesterol levels after 4 weeks of treatment (baseline 35 ± 13 mg/dl; treatment 27 ± 9 mg/dl), but the levels returned to baseline after discontinuation of ezetimibe (37 ± 13 mg/dl). The concentration of EPA did not significantly change during the study. CONCLUSION: Ezetimibe shows great promise as an add-on therapy to statins to reduce sdLDL-cholesterol-related residual risk of cardiovascular disease without affecting absorption of supplemental EPA in patients with coronary artery disease.

[Treatment of hypertriglyceridemia with omega-3 fatty acids].

Omega-3 fatty acids such as eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) have important biologic functions, including effects on membranes, eicosanoid metabolism, and gene transcription. Studies indicate that the use of EPA and DHA lowered triglyceride levels, which is accomplished by decreasing the production of hepatic triglycerides and increasing the clearance of plasma triglycerides. Recent clinical studies showed that intake of omega-3 fatty acids reduced cardiovascular events. In addition, combination therapy with omega-3 fatty acids and a statin is a safe and effective way to improve lipid levels and cardiovascular prognosis beyond the benefits provided by statin therapy alone. Our focus is to review the potential mechanisms by which these fatty acids reduce cardiovascular disease risk.