Effects of omega‐3 fatty acids on vascular smooth muscle cells: Reduction in arachidonic acid incorporation into inositol phospholipids

Yerram, Nagender R.; Spector, Arthur A.

doi:10.1007/bf02535075

Cited by 22 publications

(8 citation statements)

References 43 publications

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“…Compared to findings at basal calcium concentrations, we did not observe any effect of fish oil intake on thrombin-induced changes in intracellular free calcium. This finding is in contrast to in vitro results of Yerram and Spector [40] who observed a decrease in agonist-stimulated intracellular free calcium after incubation of vascular smooth muscle cells with fish oil.…”

Section: Discussioncontrasting

confidence: 56%

“…It has also been suggested that its blood pressure lowering effects might be due to an altered production of vasoactive prostaglandins [7,23,28]. Fish oil might alter the composition of the plasma membrane of vascu-629 lar smooth muscle cells and thus influence phosphoinositide metabolism with a concomitant alteration in intracellular calcium regulation [40,41]. Since platelets have been used as a model to study intracellular calcium regulation in patients with essential hypertension, and several authors have found that intracellular free calcium is increased in hypertensive patients [11,12,13,24], we investigated the effects of fish oil on basal and stimulated intracellular free platelet calcium.…”

Section: Discussionmentioning

confidence: 99%

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Different effects of eicosapentaenoic acid and olive oil on blood pressure, intracellular free platelet calcium, and plasma lipids in patients with essential hypertension

et al. 1993

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In a randomized, double-blind, crossover study our specific aim was to examine the effects of a dietary fish oil or olive oil supplementation on blood pressure, intracellular free platelet calcium, plasma lipoproteins, and circulating vasoactive substances such as norepinephrine, epinephrine, and renin in patients with essential hypertension. Ten hypertensive patients (WHO classes I, II) were randomly assigned to receive 9 g fish oil or 9 g olive oil daily for 6 weeks after a 4-week baseline period. The 6-week treatment periods were separated by a 4-week wash-out. During treatment with fish oil diastolic blood pressure decreased from 103 +/- 1 to 98 +/- 2 mmHg (P < 0.05) but did not change significantly during olive oil intake. Systolic blood pressure was not affected by either treatment. Intracellular free platelet calcium decreased in patients receiving fish oil (from 102 +/- 8 nM to 86 +/- 6 nM, P < 0.05) but was not significantly altered by olive oil treatment. In contrast, the dose-response curve for thrombin-induced intracellular free platelet calcium was not altered by the fish oil enriched diet. Plasma triglycerides decreased by approximately 40% in the fish oil group while low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and total cholesterol were not altered. Renin activity, norepinephrine, and epinephrine in plasma were not influenced by fish oil supplementation. We conclude that a moderate increase in dietary fish oil reduces diastolic blood pressure, intracellular free platelet calcium, and plasma triglycerides in patients with essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussioncontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Different effects of eicosapentaenoic acid and olive oil on blood pressure, intracellular free platelet calcium, and plasma lipids in patients with essential hypertension

et al. 1993

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“…Since increased intake of -3 polyunsaturated fatty acids has been associated with decreased levels of arachidonic acid incorporation into the phospholipid pool of vascular smooth muscle and endothelium, we speculated that this would lead to decreased formation of arachidonic acid metabolites in the kidney (31,32). We observed a slight decrease in arachidonic acid epoxygenase activity in renal cortical microsomes from DHA-fed rats.…”

Section: Discussionmentioning

confidence: 65%

“…It has been proposed that the hypotensive properties of fish oil may result from changes in eicosanoid metabolism (13). Vascular smooth muscle and endothelial cells have been shown to incorporate -3 polyunsaturated fatty acids at the expense of -6 polyunsaturated fatty acids (31,32). The subsequent reduction in arachidonic acid limits endogenous synthesis of vasoactive eicosanoids such as the potent vasoconstrictor TXA 2 (14).…”

Section: Discussionmentioning

confidence: 99%

Docosahexaenoic Acid is an Antihypertensive Nutrient That Affects Aldosterone Production in SHR

Engler

Goodfriend

et al. 1999

Experimental Biology and Medicine

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The effects of dietary docosahexaenoic acid (DHA), an -3 polyunsaturated fatty acid, on blood pressure and some pressure-regulating systems were measured in young spontaneously hypertensive rats (SHR). Plasma aldosterone and corticosterone levels, adrenal aldosterone production in vitro, and characteristics of adrenal angiotensin receptors were measured after 6 weeks of diet. Renal cytochrome P450 (CYP) 4A gene expression and arachidonic acid metabolism by renal microsomes were also investigated. Plasma cholesterol, triglycerides, and high-density lipoprotein cholesterol were measured. Diets contained either corn/soybean oil alone (CSO), or oil enriched with DHA. After 6 weeks, rats fed DHA had systolic blood pressures averaging 34 mmHg less than controls (P < 0.001). Plasma aldosterone levels were 33% lower in the DHA-fed animals than in controls (22 ± 3 vs. 33 ± 3.7 ng/dl, P < 0.05). Plasma levels of corticosterone were 18% lower in animals fed DHA than in controls, but this difference was not statistically significant. Adrenal glomerulosa cells from DHA-fed rats produced less aldosterone in vitro in response to angiotensin II, ACTH, or potassium. The difference was less marked when aldosterone production was stimulated by supplying exogenous corticosterone, suggesting an effect of DHA on postreceptor steps in signal transduction or the early pathway of aldosteronogenesis. We found no significant differences in angiotensin receptor subtype, number, or affinity. Production of arachidonic epoxides by renal microsomes was 17% lower in DHA-fed animals than in controls (P < 0.05). Renal cortical mRNA levels of CYP4A genes and formation of 19-and 20-hydroxyeicosatetraenoic acid (HETE) did not differ between dietary groups. Plasma total cholesterol and high-density-lipoprotein (HDL) levels were significantly reduced in SHR fed the DHA supplement, but triglyceride levels were not significantly different. The effects of DHA on steroid and eicosanoid metabolism may be part of the mechanism by which this fatty acid prevents some of the hypertension in growing SHR.

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“…Altering the lipid composition of mem branes can affect the activity of membranebound enzymes and receptor functions and overall metabolic functions [28]. Both EPA and DHA are incorporated into vascular membranes [29] which increases membrane fluidity and flexibility resulting in decreased peripheral vascular resistance [30], Structural alterations in the membrane occur with aging such that membrane receptor density de creases and fluidity is reduced due to changes in the content of membrane phospholipids and cholesterol [28], Age-related decreases in the following, in cluding F344 rat aortic (Na,K)ATPase activi ty [31], active Ca2+ uptake activity of sarco plasmic reticulum (SR) vesicles from rat myo cardium [32], P2-purinergic receptor activity [3.3], and NE-activated initial efflux response in F344 rat aortic [34] have been docu mented. Interestingly, Ca-ATPase activity in cardiac SR is reduced following fish oil feed ing in mice [35].…”

Section: Discussionmentioning

confidence: 99%

Influence of Aging on the Relaxant Responses to ω–3 Fatty Acids in Fischer 344 Rat Aorta

Engler

Engler²

1996

Gerontology

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The effect of age on the vasorelaxant properties of the ω-3 fatty acids, docosahexaenoic (DHA) and eicosapentaenoic (EPA), in isolated rat aortic rings were investigated in 4–, 15– and 24-month-old Fischer 344 rats. Increased aortic wall thickness was seen in both 15- and 24-month-old rats. Maximal contractile responses to norepinephrine (NE) were greater in intact and de-endothelialized (ENDO–) rings from 15- and 24-month-old rats; although increased sensitivity to NE was exhibited in 4-month-old rings. DHA- and EPA–induced (1-100 μmol/l) responses were similar between the three age groups in intact rings. Removal of the endothehum enhanced relaxant responses to both DHA and EPA in all three groups. EPA-induced (1-100 μmol/l) responses ranged from –4 to –28% for both 4– and 15–month ENDO– rings and -1 to -18% in 24-month ENDO–rings. DHA ENDO– ring responses (1–100 μmol/l) were -4 to -13% in 4 months, -5 to -23% in 15 months, and -0.8 to -16% in 24 months. Age differences were apparent with the ENDO– ring responses to DHA and EPA. These differences were seen with greater relaxant responses to both EPA and DHA in the 4- and 15-month-old aortic rings. Increased sensitivity and a greater maximal relaxant response to acetylcholine (ACH) was noted in the 15-month-old group. Four- and 24-month rings exhibited similar sensitivity and maximal relaxant responses to ACH. However, relaxation was decreased in 24-month rings at low ACH concentrations. These findings suggest that both functional and morphological changes occur with aging. DHA– and EPA–induced responses are not altered by aging in intact rings; however, removal of the endothehum enhances their vasorelaxant properties in all three age groups. This may be related to the direct actions of DHA and EPA on vascular smooth muscle, rather than on mechanisms associated with generation of endothelium-derived relaxing factor.

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Effects of omega‐3 fatty acids on vascular smooth muscle cells: Reduction in arachidonic acid incorporation into inositol phospholipids

Cited by 22 publications

References 43 publications

Different effects of eicosapentaenoic acid and olive oil on blood pressure, intracellular free platelet calcium, and plasma lipids in patients with essential hypertension

Different effects of eicosapentaenoic acid and olive oil on blood pressure, intracellular free platelet calcium, and plasma lipids in patients with essential hypertension

Docosahexaenoic Acid is an Antihypertensive Nutrient That Affects Aldosterone Production in SHR

Influence of Aging on the Relaxant Responses to ω–3 Fatty Acids in Fischer 344 Rat Aorta

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