Effects of Gamma‐linolenic and Eicosapentaenoic Acids on Blood Pressure in SHR

Sasaki, Susumu; Nakamura, Kunihide; Uchida, Atsushi; Fujita, Hiroshi; Itoh, Hideaki; Nakata, Tetsuo; Takeda, Kyoichi; Nakagawa, Masao

doi:10.1111/j.1440-1681.1995.tb02930.x

Cited by 7 publications

(7 citation statements)

References 8 publications

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“…It was found that in the adult SHR, DHA but not EPA reduced the vascular thromboxane-like vasoconstrictor responses in aortas after inhibition of nitric oxide with N -nitro-L-arginine. In contrast, Sasaki et al 18 showed that EPA, compared with ␥-linoleic acid, significantly reduced the rise in BP in 11-week-old SHRs.…”

Section: Discussionmentioning

confidence: 86%

“…16 Other studies have shown that dietary DHA prevented the development of hypertension in the stroke-prone SHR 17 and that EPA, compared with ␥-linoleic acid, reduced the elevation of BP in the SHR without affecting HR. 18 In contrast, in the only human study to date, EPA and DHA supplementation in healthy, nonsmoking men failed to show any difference between the 2 fatty acids or any change in BP. 19 Given the in vitro and in vivo data from animal studies that suggest that EPA and DHA may differ in their effects on BP and HR, we conducted a double-blind, randomized, placebocontrolled study to examine these possible differences in mildly hyperlipidemic men who are at increased risk of cardiovascular disease.…”

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confidence: 87%

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Docosahexaenoic Acid but Not Eicosapentaenoic Acid Lowers Ambulatory Blood Pressure and Heart Rate in Humans

et al. 1999

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Abstract-Animal studies suggest that the 2 major 3 fatty acids found in fish, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may have differential effects on blood pressure (BP) and heart rate (HR). The aim of this study was to determine whether there were significant differences in the effects of purified EPA or DHA on ambulatory BP and HR in humans. In a double-blind, placebo-controlled trial of parallel design, 59 overweight, mildly hyperlipidemic men were randomized to 4 g/d of purified EPA, DHA, or olive oil (placebo) capsules and continued their usual diets for 6 weeks. Fifty-six subjects completed the study. Key Words: eicosapentaenoic acid Ⅲ docosahexaenoic acid Ⅲ fatty acids Ⅲ blood pressure Ⅲ heart rate C urrent evidence from epidemiological studies, clinical trials, and experimental animal studies suggests that 3 fatty acids of marine origin may be protective against cardiovascular disease. 1 Most studies that assessed the potential cardiovascular benefits of 3 fatty acids have focused largely on the importance of eicosapentaenoic acid (EPA), with little attention given to the relative effect of docosahexaenoic acid (DHA). This is probably attributable to the fact that the majority of commercial marine oil preparations as well as most, but not all, fish species contain more EPA than DHA. In addition, EPA, unlike DHA, is a substrate for the cyclooxygenase and lipoxygenase enzymes involved in eicosanoid metabolism.Fish oil supplementation in humans results in substantial increases in plasma and tissue 3 fatty acids, particularly EPA and DHA, but with variable incorporation in different phospholipid classes in different tissues. In vitro animal and human studies have shown that EPA and DHA are differentially incorporated into plasma, 2 platelet, 3,4 and tissue lipids. 4 These differences may play an important role in the utilization and metabolism of the 2 fatty acids. For example, EPA and DHA differ in their effects on membrane fluidity and the activities of membrane-bound enzymes 5 and on neutrophilmediated endothelial detachment. 6 Compelling evidence shows that in vitro DHA but not EPA decreased cytokine-induced expression of endothelial leukocyte adhesion molecules. 7 Recent reports have described differences in lipid metabolism 8,9 and platelet aggregation. 10 An antihypertensive effect of fish oils has been demonstrated in hypertensive patients, 11-14 although generally only when relatively large doses of fish oils have been used. We recently reported that daily fish meals that provide 3.65 g/d of 3 fatty acids significantly reduced blood pressure (BP) in overweight, treated hypertensives. 15 This study addresses the question of whether EPA and DHA have differential effects on BP and heart rate (HR) in humans. In support of a differential effect of EPA and DHA on BP control, McLennan et al 16 recently reported that DHA was more effective than EPA at retarding the development of hypertension in spontaneously hypertensive rats (SHR) but not in adult SHR with already established hyperten...

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Section: Discussionmentioning

confidence: 86%

mentioning

confidence: 87%

Docosahexaenoic Acid but Not Eicosapentaenoic Acid Lowers Ambulatory Blood Pressure and Heart Rate in Humans

et al. 1999

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“…More than a decade ago, LA was reported to inhibit platelet adhesion and aggregation by reducing the formation of the vasoactive eicosanoid thromboxane A 2 (TXA 2 ) [9]. Moreover, PGE, generated from dihomo-GLA, was demonstrated to exhibit anti-aggregatory, anti-inflammatory and antiproliferative effects [8,10]. Contradictory reports came from Bhadra et al [11] who showed that Cu +2 ion-induced peroxidation of lipoprotein cholesterol to oxysterols and aortic accumulation of lipid peroxides were significantly higher in rabbits fed corn oil compared to animals fed saturated fat and that the difference persisted even at 5 weeks after switching to chow diet.…”

Section: Introductionmentioning

confidence: 99%

“…The anti-atherogenic effects of UFAs may be attributed to their LDL-Clowering effects [6,14], to their anti-inflammatory effects on vascular cells [15] and to their antithrombotic effects [8][9][10]. The mechanisms of action of fatty acids are not completely understood and are complex because they are involved at various stages of cell biology, including membrane structure, cell metabolism, energy production and cell signaling.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Effects of Dietary Saturated, Mono-, and n–6 Polyunsaturated Fatty Acids on Blood Lipid Profile, Oxidant Stress, Prostanoid Synthesis and Aortic Histology in Rabbits

Bayındır¹,

Özmen²,

Mutaf³

et al. 2002

Ann Nutr Metab

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Background/Aims: To compare the effects of saturated, monounsaturated and polyunsaturated n–6 fatty acid-enriched diets on the development of atherosclerosis and thrombosis in New Zealand white male rabbits, 3- to 6-month-old animals were supplemented daily (10 g/100 g diet) with butter (n = 8), olive oil (n = 8) or corn oil (n = 8) by oral administration for 7 weeks. Methods: Total cholesterol (TC), HDL- (HDL-C) and LDL-cholesterol (LDL-C), triglycerides (TG), apolipoprotein A-1 (ApoA-1), apolipoprotein B (ApoB), lipid peroxides as thiobarbituric acid-reactive substances (TBARS), thromboxane B₂ (TXB₂) and 6-ketoprostaglandin F_1α (6-ketoPGF_1α) concentrations were determined in blood samples drawn before and after each group was fed the different dietary regimens. Histological examination was performed on the aortic tissues. Results: After 7 weeks, TC, ApoB and TXB₂ increased significantly (p < 0.05) in the butter-fed animals compared to pre-experimental concentrations. Olive oil administration lead to a significant (p < 0.05) decrease in TC and ApoB levels. The corn oil-enriched diet decreased TC, LDL-C concentrations, TC/HDL-C ratios and 6-ketoPGF_1α (stable metabolite of prostacyclin-PGI_2; p < 0.05 for all) but increased TBARS levels and TXB₂/6-ketoPGF_1α ratios. Light microscopic findings were in accordance with these biochemical alterations. Conclusion: Although effective in lipid lowering, corn oil increased oxidant stress as evidenced by increased TBARS and induced endothelial damage which lead to a reduction in PGI₂ synthesis and consequently to an increase in the TXB₂/6-ketoPGF_1α ratio. Olive oil administration did not induce oxidant stress and it had no affect on PGI₂ and TXB₂ levels which are implicated in platelet aggregation. These findings suggest that oleic acid is more effective than linoleic acid in the protection of endothelial integrity.

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“…Experiments using purified forms of the major components of these oils-EPA (20:5n-3) and DHA (22:6n-3)-have shown a decrease in blood pressure in patients suffering from hypertension (6) and in SHR (7,8). Contradictory reports show no protective effect of the consumption of fish oil-or of its derivatives-on hypertension (9)(10)(11), if used at low doses.…”

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confidence: 99%

Antihypertensive effects of a dietary unsaturated FA mixture in spontaneously hypertensive rats

Bellenger-Germain

Poisson

Narce

2002

Lipids

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The aim of the present study was to investigate whether a mixture of dietary n-6 and n-3 PUFA could lower blood pressure in spontaneously hypertensive rats (SHR) of different ages. In addition, we studied how such a treatment could normalize the FA composition of plasma TAG and cholesterol esters (CE), and of red blood cell (RBC) total lipids. SHR (ages 4, 19, and 50 wk) were fed a normal diet (control groups) or a semisynthetic diet containing a mixture of gamma-linolenic acid (GLA), EPA, and DHA (experimental groups). Systolic blood pressure was measured at regular intervals. After 11 wk of consuming this diet, plasma TAG and CE were separated by TLC and analyzed for their FA composition. Total FA composition of RBC was also determined. The degree to which blood pressure was elevated was reduced in SHR after 11 wk of diet. The largest decrease was obtained with the oldest animals. In RBC, EPA and DHA contents increased. In plasma TAG and CE, EPA, DHA, and GLA increased whereas arachidonic acid decreased. The n-6 and n-3 unsaturated FA mix slowed the development of hypertension in young SHR and decreased blood pressure in adult and aged SHR. In addition, the present treatment altered the n-3 and n-6 PUFA content of SHR lipids to that seen in normotensive rats.

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Effects of Gamma‐linolenic and Eicosapentaenoic Acids on Blood Pressure in SHR

Cited by 7 publications

References 8 publications

Docosahexaenoic Acid but Not Eicosapentaenoic Acid Lowers Ambulatory Blood Pressure and Heart Rate in Humans

Docosahexaenoic Acid but Not Eicosapentaenoic Acid Lowers Ambulatory Blood Pressure and Heart Rate in Humans

Comparison of the Effects of Dietary Saturated, Mono-, and n–6 Polyunsaturated Fatty Acids on Blood Lipid Profile, Oxidant Stress, Prostanoid Synthesis and Aortic Histology in Rabbits

Antihypertensive effects of a dietary unsaturated FA mixture in spontaneously hypertensive rats

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