QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Frenoux, J.-M. R. Articles by Prost, J. L. Search for Related Content PubMed PubMed Citation Articles by Frenoux, J.-M. R. Articles by Prost, J. L.

---

Article

A Polyunsaturated Fatty Acid Diet Lowers Blood Pressure and Improves Antioxidant Status in Spontaneously Hypertensive Rats¹

UPRES, Lipids and Nutrition 2422, Nutrition Cellulaire et Métabolique, Université de Bourgogne, 21078 Dijon Cedex, France and ^* Centre Européen de Recherches et d’Analyses, 21560 Couternon France

²To whom correspondence should be addressed. E-mail: jbellev{at}u-bourgogne.fr

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
-Linolenic acid [GLA, 18:3(n-6)], eicosapentaenoic acid [EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)] have been reported to prevent cardiovascular diseases. However, they are highly unsaturated and therefore more sensitive to oxidation damage. We investigated the effects of a diet rich in these polyunsaturated fatty acids (PUFA) on blood pressure, plasma and lipoprotein lipid concentrations, total antioxidant status, lipid peroxidation and platelet function in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Five-week-old SHR and WKY rats were fed for 10 wk either a diet containing Isio 4 oil or a diet rich in GLA, EPA and DHA (5.65, 6.39 and 4.94 g/kg dry diet, respectively). The total antioxidant status was assayed by monitoring the rate of free radical–induced hemolysis. VLDL-LDL sensitivity to copper-induced lipid peroxidation was determined as the production of thiobarbituric acid reactive substances. After dietary PUFA supplementation, a significant decrease in blood pressure of SHR rats (-20 mm Hg) was observed and the total antioxidant status was enhanced. VLDL-LDL resistance to copper-induced peroxidation was increased in both strains. The PUFA supplementation did not change platelet maximum aggregation in SHR rats, but it decreased the aggregation speed. In hypertensive rats, GLA + EPA + DHA supplementation lowers blood pressure, enhances total anti-oxidant status and resistance to lipid peroxidation, diminishes platelet aggregation speed and lowers plasma lipid concentrations. Thus, it enhances protection against cardiovascular diseases. Therefore, nutritional recommendations for cardiovascular disease prevention should take into account the pharmacologic properties of GLA, EPA and DHA.

KEY WORDS: • hypertension • polyunsaturated fatty acids • antioxidant status • lipoproteins • spontaneously hypertensive rats

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Clinical and epidemiological studies (1 ,2) have shown the cardiovascular protective effects of fish oils and polyunsaturated fatty acids (PUFA).³ In particular, these substances have been reported to lower blood pressure and prevent the development of hypertension (3 4 5 6) , which is one of the most critical factors involved in cardiovascular pathologies such as atherosclerosis or stroke. The protective effects of fish oils seem to be due mainly to two fatty acids, i.e., eicosapentaenoic acid [EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)]. Dietary supplementation with these fatty acids has provided evidence of their cardiovascular protective effects and their ability to lower blood pressure (3 ,5 ,6) . Nevertheless, DHA seems to be the more powerful in reducing blood pressure and cardiovascular risk (5) . The mechanisms leading to these protective effects remain unclear. These fatty acids are precursors of the 3-series prostaglandins, which are antiaggregators and vasodilators. Moreover, they have been found to inhibit 5 desaturase (7) , which converts 20:3(n-6) to 20:4(n-6) (first precursor of the 2-series prostaglandins) and 20:4(n-3) to 20:5(n-3) (first precursor of the 3-series prostaglandins). Thus, lower 5 desaturase activity leads to lower 20:4(n-6) amounts available for proaggregator thromboxane A₂ synthesis and accumulation of 20:3(n-6), the first precursor of vasodilator prostaglandin E₁ (7) . However, diets rich in EPA and DHA also inhibit 6 desaturase (7) , which converts 18:2(n-6) into 18:3(n-6) and 18:3(n-3) into 18:4(n-3). The 18:2(n-6) to 18:3(n-6) conversion is the rate-limiting enzyme step in the biosynthesis of 20:3(n-6) from 18:2(n-6). Thus, a recent concept in nutritional prevention of cardiovascular disease is to by-pass this enzymatic step by increasing amounts of dietary -linolenic acid [GLA, 18:3(n-6)] (4) . This fatty acid is a highly potent nutrient in lowering blood pressure (4) . It is quickly converted into 20:3(n-6), which is the precursor of the antiaggregator and vasodilator prostaglandin E₁.

Other mechanisms may also be involved in PUFA cardiovascular protective effects such as the lowering of platelet aggregation (8) . The (n-3) fatty acids inhibit vasoconstrictor thromboxane A₂ biosynthesis, but blood pressure values are not correlated with plasma thromboxane A₂ concentration in SHR rats (3) . However, decreased 20:4(n-6) levels in platelet lipids might decrease thromboxane A₂ synthesis and platelet sensitivity, thus resulting in lower cardiovascular risks.

Plasma total cholesterol concentrations are also considered as a marker of susceptibility to cardiovascular disease, but the most relevant risk factor is the LDL cholesterol (LDL-C) concentration, and the LDL-C to HDL-C ratio value, which is positively correlated with the incidence of cardiovascular disease (9) . Diets rich in (n-3) PUFA improve the plasma lipid profile, reducing plasma cholesterol and triacylglycerol concentrations in mice (10) .

Antioxidant status (11 ,12) is another factor closely related to cardiovascular pathologies. Plasma concentrations of oxidized LDL are strongly related to cardiovascular disease. These modified LDL are scavenged by macrophages and contribute to foam cell formation, accumulation on vessel walls and atherosclerosis development (12) . PUFA such as GLA, EPA or DHA are highly unsaturated and therefore exhibit hypersensitivity to lipid peroxidation (12 ,13) . This might lead to increased plasma atherogenic particles, which could counteract the beneficial effects on blood pressure, platelet metabolism and lipid profile.

The aim of this study was to determine whether the antihypertensive effect of a diet enriched in 20:5(n-3) (EPA), 22:6(n-3) (DHA) and 18:3(n-6) (GLA) is associated with impaired antioxidant status. This study was carried out using spontaneously hypertensive rats (SHR) as a genetic hypertension model, compared with normotensive Wistar Kyoto rats (WKY).

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Animals and diets.

Five-week-old SHR (n = 20) and WKY (n = 20) rats were purchased from IFFA-CREDO (L’Arbresle, France). They were maintained at 24°C and constant humidity (60%) with a 12-h light:dark cycle. Rats were divided into four groups of 10 rats fed for 10 wk a purified Isio 4 oil–containing diet (Lesieur, Neuilly-sur-Seine, France) enriched (SHR-EPAX and WKY-EPAX groups) or not (SHR-Isio and WKY-Isio groups) with a mix of EPAX6000 and GLA80 (EPAX diet, Callanish, Isle of Lewis, UK). Both diets contained 5 g/100 g lipid. The EPAX diet provided large amounts of GLA [18:3(n-6), 5.65 g/kg dry diet], EPA [20:5(n-3), 6.39 g/kg dry diet] and DHA [22:6(n-3), 4.94 g/kg dry diet]. Composition of the diets is given in Table 1 . Food and tap water were freely available. We followed the general guidelines for the care and use of laboratory animals recommended by the Council of European Communities (14) .

Platelet aggregation.

Platelet-rich plasma was obtained by low speed centrifugation (150 x g, 18 min). It was then centrifuged (1000 x g, 18 min) to obtain a platelet pellet and a platelet-poor plasma supernatant. The remaining blood was centrifuged (1000 x g, 18 min) to obtain plasma. Both plasma supernatants were pooled for plasma determinations. The platelet pellet was resuspended in Tyrode-HEPES (5 mmol/L), pH 7.35 buffer (15) and platelet number was adjusted to 2 x 10¹¹ platelets/L before use. Aggregation assays were performed according to the turbidimetric method of Born (16) . Briefly, the platelet suspension was placed into a glass tube prewarmed at 37°C in an aggregometer (Labintec, Montpellier, France). Calcium chloride (2 µL; 0.3 µmol/L) and 2 µL thrombin (Sigma, L’Isle d’Abeau, France) solution (1 x 10⁴ U/L) were added after 1.5 and 2 min, respectively. Aggregation was monitored with a strip chart recorder (LKB, Bromma, Sweden). Transmissions (100 and 0%) were adjusted using buffer and platelet suspension, respectively. Assays were performed in triplicate. The percentage of maximum aggregation and the time to reach this value were measured.

Plasma determinations.

Plasma (2 mL) was used for -tocopherol determination (17) . Briefly, 10 µg of Tocol (internal standard, Lara Spiral, Couternon, France) and 2 mL of chilled ethanol were added to the plasma. -Tocopherol was extracted twice by 5 mL hexane. The hexane upper phase containing -tocopherol was collected after 10 min centrifugation (1600 x g, 4°C). Then it was dried under nitrogen and resuspended in 400 µL methanol. -Tocopherol determination was performed by HPLC on a C18 column (HP ODS Hypersil C18; 200 mm x 4.6 mm; Lara Spiral). Peaks were detected by a UV detector at 290 nm. Protein measurement was performed according to Schacterle and Pollack (18) using bovine serum albumin as a standard. Plasma triacylglycerol, total and free cholesterol concentrations were determined by enzymatic method (Boehringer kits, Mannheim, Germany) using glycerol and cholesterol as standards, respectively.

Total antioxidant status.

The total antioxidant status was defined as the capacity of RBC to withstand free radical–induced hemolysis and was measured as described previously by Blache and Prost (19) . This method, based on monitoring the rate of free radical–induced hemolysis, employed a French Patent Pending (Lara Spiral). Blache and Prost (19) have clearly demonstrated that if at least one component of the antiradical detoxification system (antioxidant, enzyme) is impaired, a shift of the hemolysis curve is obtained toward shorter times.

Briefly, total blood of experimental rats was diluted (1:20, v/v) with sodium chloride (8.77 g/L) and assayed using microplate titration. Diluted blood (100 µL) was added with a free radical generator (2,2'-azo-bis-2-amidinopropane, 170 µL, 100 mmol/L; Lara Spiral). The kinetics of RBC resistance to hemolysis were determined at 37°C by continuous monitoring of changes in 450-nm absorbance using a microplate titrator (iEMS reader MF, Lara Spiral). The time to reach 50% of total hemolysis (T_{50% hemolysis}) was used for group comparisons.

As described by Blache and Prost (19) , an application of this method is the determination of plasma total antioxidant capability by incubating "standard" RBC (from a Wistar rat fed a commercial diet) with plasma samples to test their total free radical scavenging properties. The rate of hemolysis was monitored as described above. Briefly, "standard" blood from a Wistar rat was diluted with an 8.77 g/L sodium chloride solution (1:20, v/v) and plasma from experimental rats was diluted with the same sodium chloride solution (1:25, v/v). Then, diluted "standard" blood (100 µL) and diluted plasma (85 µL) were pooled and the free radical generator was added (85 µL, 100 mmol/L). RBC resistance to free radical aggression was monitored as described above.

Fatty acid determinations.

Total lipids of blood platelets and RBC membranes were extracted according to Folch et al. (20) and then methylated (21) . The fatty acid composition was determined by gas-liquid chromatography (21) .

Lipid peroxidation.

The VLDL-LDL fraction obtained by precipitation with dextran sulfate (0.91 g/L) and MgCl₂ (91 mmol/L) (22) was used for this study. As described by Frémont et al. (23) , 100 µL (250 µg protein) of VLDL-LDL fraction was added to 900 µL PBS and incubated for 24 h at 37°C with 20 µL CuSO₄ (0.25 mmol/L). The production of thiobarbituric acid reactive substances (TBARS) was determined by the spectrophotometric method. Malondialdehyde, prepared by tetraethoxypropane hydrolysis, was used for establishing a standard curve. Results were expressed as nmol TBARS produced per mg of VLDL-LDL protein in 24 h.

Statistics.

Values are means ± SD. Statistical analysis of the data was carried out using STATISTICA (version 4.1, Statsoft, Tulsa, OK). Data were tested by two-way ANOVA followed by Fisher’s least significant difference test. A difference of P < 0.05 was considered significant.

	RESULTS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
The four groups of rats did not differ in body weight during the experiment. At the end of the experiment, rats were 15 wk old and hypertension had developed in SHR rats. SHR-EPAX and SHR-Isio groups had higher blood pressures than age-matched WKY-EPAX and WKY-Isio groups (Fig. 1 , P 0.01). Hypertensive rats fed the EPAX diet had lower blood pressures than age-matched hypertensive rats fed the Isio diet (P < 0.05). Ten-week-old normotensive rats fed the EPAX diet had lower blood pressure than 10-wk-old normotensive rats fed the Isio diet (P = 0.016), but there was no significant difference in blood pressures between the 15-wk-old normotensive groups.

View larger version (62K): [in this window] [in a new window]   Figure 1. Blood pressures of 10- and 15-wk-old normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) fed the Isio and the EPAX diets. Values are the means ± SD, n = 10. Each individual blood pressure value was the mean of five measurements for each rat. All differences between 10- and 15-wk-old rats fed the same diet were significant, P < 0.01.

Copper-induced lipid peroxidation of VLDL-LDL (Table 3) was lower in hypertensive rats than in normotensive rats (P < 0.05). In normotensive rats, the EPAX diet induced a greater decrease in lipid peroxidation of VLDL-LDL (-50% in WKY-EPAX vs. WKY-Isio group; P < 0.05) than in hypertensive rats (-30% in SHR-EPAX vs. SHR-Isio group; P < 0.05).

Hypertensive rats had lower plasma lipid (phospholipids, unesterified and esterified cholesterol, triacylglycerols) concentrations than normotensive rats (-33, -38, -35 and -47%, respectively, in SHR-Isio vs. WKY-Isio group, Table 4 ). These concentrations were decreased in both strains by the EPAX diet (-13, -22, -15 and -4%, respectively in SHR-EPAX vs. SHR-Isio group and -21, -24, -21 and -43%, respectively in WKY-EPAX vs. WKY-Isio group, Table 4 ).

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

The lower blood pressure of the 15-wk-old SHR-EPAX group (compared with the age-matched SHR-Isio group) was likely attributable to the GLA supplementation (4) more than to the EPA + DHA [20:5(n-3) + 22:6(n-3)] supplementation. Engler et al. (24) found a significant decrease in blood pressure of 15-wk-old SHR and WKY rats fed a diet rich in GLA (borage oil) for 5 wk. This is partly the result of a modification of the renin angiotensin aldosterone system (24) . Moreover, in our laboratory, Narce et al. (7) demonstrated that a diet rich in EPA and DHA but free of GLA fed for 9 wk does not modify the blood pressure of 13-wk-old SHR rats compared with age-matched SHR rats fed the Isio diet. Another hypothesis for the antihypertensive effect of GLA would be an increase in vasodilator prostaglandin E₁ production. Thus, GLA is quickly converted into 20:3(n-6), which is the first precursor of prostaglandin E₁. St. Louis et al. (25) showed that the GLA-induced blood pressure decrease is inhibited by aspirin, which is an inhibitor of cyclooxygenase, a critical enzyme in the biosynthesis of prostaglandins and especially that of prostaglandin E₁.

Hypertensive rats had lower plasma -tocopherol concentrations than normotensive rats. Enhanced superoxide anion production has been demonstrated in Stroke-Prone SHR rats compared with WKY rats (26) . This may explain in part the lower plasma -tocopherol concentration in hypertensive rats because -tocopherol is used to scavenge free radicals. Moreover, SHR aorta is more sensitive to free radical–induced contractions than WKY aorta (27) . Increased free radical synthesis associated with enhanced vessel free radical sensitivity might be one cause for hypertension development in the SHR strain. It would also lead to greater antioxidant requirements. The EPAX diet had no effect on plasma -tocopherol concentrations in spite of its high sensitivity to oxidation (11 ,12) .

Hypertensive and normotensive rats fed the Isio diet did not differ in total antioxidant status (Table 3) . However, the SHR-Isio group had enhanced VLDL-LDL resistance to copper-induced lipid peroxidation compared with the WKY-Isio group (Table 3) . The total antioxidant status was improved by the EPAX diet only in hypertensive rats. This is the result of increased VLDL-LDL resistance to lipid peroxidation and increased plasma total antioxidant capability. Increased antioxidant defenses, after dietary enrichment with EPA, were described previously in mice by Demoz et al. (10) , who found enhanced hepatic antioxidant enzyme activities and decreased hepatic lipid peroxide concentrations when EPA was used at a hypotriglyceridemic dose.

Moreover, Van Den Berg et al. (28) found a decrease in RBC hemolysis in rabbits after dietary enrichment with fish oil. Their results are related to PUFA enrichment of membranes, which serve as an "oxidizable buffer." They demonstrated that membrane highly unsaturated fatty acids [20:5(n-3), 22:5(n-3) and 22:6(n-3)] were first oxidized and lipid peroxidation of the other fatty acids was then decreased (28) . According to this hypothesis, in our experiment, enhanced resistance of RBC to hemolysis associated with increased membrane highly unsaturated fatty acid [20:5(n-3), 22:5(n-3) and 22:6(n-3), Table 6 ] levels may explain in part the higher total antioxidant status of SHR rats fed the EPAX diet.

However, dietary PUFA enrichment is generally widely associated with increased lipid peroxidation (12 ,28) . In contrast, in both hypertensive and normotensive rats fed the EPAX diet, we found an enhanced resistance of VLDL-LDL particles to lipid peroxidation. This effect might be due in part to the large vitamin E levels of the diets, which may prevent PUFA peroxidation. However, because vitamin E concentrations were the same in the Isio and EPAX diets, one part of the enhanced resistance of VLDL-LDL to lipid peroxidation in the EPAX-fed groups could be attributable to the PUFA levels in the EPAX diet. A partial explanation may be provided by the findings of Ohara et al. (29) who showed in rabbits that free radical generation is positively correlated with plasma total cholesterol concentration. Thus, the decrease in plasma total cholesterol concentrations observed in rats fed the EPAX diet (Table 4) might lead to lower free radical production and then to decreased lipid peroxidation (Table 3) .

Free hemoglobin released from RBC hemolysis is a powerful platelet activator (30 ,31) . Thus, increased RBC resistance to hemolysis observed in hypertensive rats fed the EPAX diet would lead to lower plasma free hemoglobin concentrations and could thus explain in part the antiaggregant effects of (n-3) fatty acids (8) . However, in our study, the EPAX diet had no effect on maximum aggregation of platelets from SHR rats. This may be related to the 20:4(n-6) contents in platelet membranes because it is the first precursor of proaggregant thromboxane A₂. We found no significant difference in 20:4(n-6) contents of platelet membranes between both SHR-Isio and SHR-EPAX groups (Table 5) . Thus, the synthesis of thromboxane A₂ would not be modified in the SHR-EPAX group, compared with the SHR-Isio group. This might explain in part the inability of the EPAX diet to diminish platelet aggregation in hypertensive rats. However, we observed a decrease in platelet aggregation speed in the WKY and SHR rats fed the EPAX diet, compared with rats fed the Isio diet. This would lead to increased delay before thrombus formation and would thus contribute to the cardiovascular beneficial effects of the (n-3) PUFA (8 ,32) .

Cardiovascular protective effects of PUFA might be the result of their hemodynamic effects. Auch-Schwelk et al. (27) demonstrated that oxygen free radicals induce greater contractions in SHR aortas than in WKY aortas. These contractions are dose dependent and seem to be the result of calcium influx alteration in endothelial cells through voltage-operated channels (27) . Thus, in the SHR-EPAX group, increased plasma antioxidant capability (Table 3) , which results in enhanced free radical scavenging properties, might lead to greater resistance to free radical–induced aortic contractions and could thus explain in part the antihypertensive effect of the EPAX diet.

The EPAX diet had a lipid-lowering effect (Table 4) in both hypertensive and normotensive rats. This confirms the previous findings concerning PUFA-enriched diets and lipid profile. Decreases in both plasma triacylglycerol (10) and cholesterol concentrations (33) were reported previously in rats fed diets supplemented with fish oil rich in (n-3) PUFA. As demonstrated in rabbits by Ohara et al. (29) , lower plasma total cholesterol concentrations might lead to lower free radical production and could thus explain in part the increased resistance to oxidative stress observed in SHR rats fed the EPAX diet.

In conclusion, the diet, which is enriched in 18:3(n-6), 20:5(n-3) and 22:6(n-3), displays numerous protective effects against cardiovascular diseases. First, it has an antihypertensive effect associated with increased resistance to free radical aggression and lipid peroxidation, diminished aggregation speed and lower plasma lipid concentrations. These results support the hypothesis that 18:3(n-6), 20:5(n-3) and 22:6(n-3) are effective nutrients in preventing hypertension and cardiovascular diseases such as atherosclerosis. Further studies are required to test the underlying mechanisms involved in this antihypertensive effect and to check these results before utilization in hypertensive humans.

	ACKNOWLEDGMENTS

 
We thank Anne Magnet, an English for Specific Purposes linguist at the University of Burgundy for editing the manuscript. We also thank Callanish Ltd. (Isle of Lewis, UK) for providing EPAX6000 and GLA80.

	FOOTNOTES

 
¹ Supported by the Regional Council of Burgundy and by the Comité Mixte d’Evaluation et de Prospective de la Coopération Interuniversitaire Franco-Algérienne.

³ Abbreviations used: DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; GLA, -linolenic acid; HDL-C, total cholesterol of HDL fraction; LDL-C, total cholesterol of LDL fraction; SHR-EPAX, spontaneously hypertensive rats fed the EPAX diet; SHR-Isio, spontaneously hypertensive rats fed the Isio diet; TBARS, thiobarbituric acid reactive substances; WKY-EPAX, Wistar Kyoto rats fed the EPAX diet; WKY-Isio, Wistar Kyoto rats fed the Isio diet.

Manuscript received July 17, 2000. Initial review completed August 23, 2000. Revision accepted October 13, 2000.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 

1. Morris M. C. Dietary fats and blood pressure. J. Cardiovasc. Risk 1994;1:21-30[Medline]

2. Sacks F. M., Hebert P., Appel L. J., Borhani N. O., Applegate W. B., Cohen J. D., Cutler J. A., Kirchner K. A., Kuller L. H., Roth K. J. The effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the Trials of Hypertension Prevention. Trials of Hypertension Prevention Collaborative Research Group. J Hypertens 1994;suppl. 12:S23-S31

3. Chen H. W., Lii C. K., Chen W. T., Wang M. L., Ou C. C. Blood pressure-lowering effect of fish oil is independent of thromboxane A₂ level in spontaneously hypertensive rats. Prostaglandins Leukot. Essent. Fatty Acids 1996;54:147-154[Medline]

4. Engler M. M. -Linolenic acid: a potent blood pressure lowering nutrient. Huang Y.-S. Mills D. E. eds. -Linolenic Acid: Metabolism and Its Roles in Nutrition and Medicine 1996:200-217 AOCS Press Champaign, IL

5. Mori T. A., Bao D. Q., Burke V., Puddey I. B., Beilin L. J. Docosahexaenoic acid but not eicosapentaenoic acid lowers ambulatory blood pressure and heart rate in humans. Hypertension 1999;34:253-260[Abstract/Free Full Text]

6. Prisco D., Paniccia R., Bandinelli B., Filippini M., Francalanci I., Giusti B., Giurlani L., Gensini G. F., Abbate R., Neri Serneri G. G. Effect of medium-term supplementation with a moderate dose of n-3 polyunsaturated fatty acids on blood pressure in mild hypertensive patients. Thromb. Res. 1998;91:105-112[Medline]

7. Narce M., Frenoux J. M., Dardel V., Foucher C., Germain S., Delachambre,M. C. & Poisson J. P. Fatty acid metabolism, pharmacological nutrients and hypertension. Biochimie 1997;79:135-138[Medline]

8. Nieuwenhuys C. M., Hornstra G. The effects of purified eicosapentaenoic and docosahexaenoic acids on arterial thrombosis tendency and platelet function in rats. Biochim. Biophys. Acta 1998;1390:313-322[Medline]

9. O’Keefe J. H., Jr, Lavie C. J., Jr, McCallister B. D. Insights into the pathogenesis and prevention of coronary artery disease. Mayo Clin. Proc. 1995;70:69-79[Abstract]

10. Demoz A., Willumsen N., Berge R. K. Eicosapentaenoic acid at hypotriglyceridemic dose enhances the hepatic antioxidant defense in mice. Lipids 1992;27:968-971[Medline]

11. Prabha P. S., Das U. N., Koratkar R., Sagar P. S., Ramesh G. Free radical generation, lipid peroxidation and essential fatty acids in uncontrolled essential hypertension. Prostaglandins Leukot. Essent. Fatty Acids 1990;41:27-33[Medline]

12. Suzukawa M., Abbey M., Howe P. R., Nestel P. J. Effects of fish oil fatty acids on low density lipoprotein size, oxidizability, and uptake by macrophages. J. Lipid Res. 1995;36:473-484[Abstract]

13. Nenseter M. S., Drevon C. A. Dietary polyunsaturates and peroxidation of low density lipoprotein. Curr. Opin. Lipidol. 1996;7:8-13[Medline]

14. Council of European Communities Council instructions about the protection of living animals used in scientific investigations. Official Journal of European Communities 1986;L358(JO86/609/CEE):1-18

15. Lagarde M., Bryon P. A., Guichardant M., Dechavanne M. A simple and efficient method for platelet isolation from their plasma. Thromb. Res. 1980;17:581-588[Medline]

16. Born G. V. R. Aggregation of blood platelets by adenosine diphosphate and its reversal. Nature (Lond.) 1962;194:927-929[Medline]

17. Jezequel-Cuer M., Le Moel G., Mounie J., Peynet J., Le Bizec C., Vernet M. H., Artur Y., Laschi-Loquerie A., Troupel S. Dosage de l’alpha-tocophérol sérique ou plasmatique par chromatographie liquide haute performance: optimisation du mode opératoire. Ann. Biol. Clin. 1995;53:343-352

18. Schacterle G. R., Pollack R. L. A simplified method for the quantitative assay of small amounts of protein in biologic material. Anal. Biochem. 1973;51:654-655[Medline]

19. Blache D., Prost M. Free radical attack: biological test for human resistance capability. Ponnamperuma C. Gehrke C. W. eds. A Lunar-Based Chemical Analysis Laboratory 1992:82-98 Deepak A. Hampton, VA.

20. Folch J., Lees M., Sloane-Stanley G. H. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 1957;226:497-509[Free Full Text]

21. Slover H. T., Lanza E. Quantitative analysis of food fatty acids by capillary gas chromatography. J. Am. Oil. Chem. Soc. 1979;56:933-943

22. Sjoblom L., Eklund A. Determination of HDL₂ cholesterol by precipitation with dextran sulfate and magnesium chloride: establishing optimal conditions for rat plasma. Lipids 1989;24:532-534[Medline]

23. Frémont L., Gozzelino M. T., Franchi M. P., Linard A. Dietary flavonoids reduce lipid peroxidation in rats fed polyunsaturated or monounsaturated fat diets. J. Nutr. 1998;128:1495-1502[Abstract/Free Full Text]

24. Engler M. M., Schambelan M., Engler M. B., Ball D. L., Goodfriend T. L. Effects of dietary gamma-linolenic acid on blood pressure and adrenal angiotensin receptors in hypertensive rats. Proc. Soc. Exp. Biol. Med. 1998;218:234-237[Medline]

25. St. Louis C., Lee R. M., Rosenfeld J., Fargas-Babjak A. Antihypertensive effect of gamma-linolenic acid in spontaneously hypertensive rats. Hypertension 1992;19(suppl. II):111-115

26. Kerr S., Brosnan M. J., McIntyre M., Reid J. L., Dominiczak A. F., Hamilton C. A. Superoxide anion production is increased in a model of genetic hypertension: role of the endothelium. Hypertension 1999;33:1353-1358[Abstract/Free Full Text]

27. Auch-Schwelk W., Katusic Z. S., Vanhoutte P. M. Contractions to oxygen-derived free radicals are augmented in aorta of the spontaneously hypertensive rat. Hypertension 1989;13:859-864[Abstract/Free Full Text]

28. Van Den Berg J. J., De Fouw N. J., Kuypers F. A., Roelofsen B., Houtsmuller U. M., Op Den Kamp J. A. Increased n-3 polyunsaturated fatty acid content of red blood cells from fish oil-fed rabbits increases in vitro lipid peroxidation, but decreases hemolysis. Free Radic. Biol. Med. 1991;11:393-399[Medline]

29. Ohara Y., Peterson T. E., Harrison D. G. Hypercholesterolemia increases endothelial superoxide anion production. J. Clin. Investig. 1993;91:2546-2551

30. Iuliano L., Colavita A. R., Leo R., Pratico D., Violi F. Oxygen free radicals and platelet activation. Free Radic. Biol. Med. 1997;22:999-1006[Medline]

31. Iuliano L., Violi F., Pedersen J. Z., Pratico D., Rotilio G., Balsano F. Free radical-mediated platelet activation by hemoglobin released from red blood cells. Arch. Biochem. Biophys. 1992;299:220-224[Medline]

32. Simopoulos A. P. Essential fatty acids in health and chronic disease. Am. J Clin. Nutr. 1999;70(suppl. 3):560S-569S[Abstract/Free Full Text]

33. Horrocks L. A., Yeo Y. K. Health benefits of docosahexaenoic acid (DHA). Pharmacol. Res. 1999;40:211-225[Medline]

This article has been cited by other articles:

				J Schwartz, K Dube, W Sichert-Hellert, F Kannenberg, C Kunz, H Kalhoff, and M Kersting Modification of dietary polyunsaturated fatty acids via complementary food enhances n-3 long-chain polyunsaturated fatty acid synthesis in healthy infants: a double blinded randomised controlled trial Arch. Dis. Child., November 1, 2009; 94(11): 876 - 882. [Abstract] [Full Text] [PDF]

				M. M. Diaz Encarnacion, G. M. Warner, C. E. Gray, J. Cheng, H. K. H. Keryakos, K. A. Nath, and J. P. Grande Signaling pathways modulated by fish oil in salt-sensitive hypertension Am J Physiol Renal Physiol, June 1, 2008; 294(6): F1323 - F1335. [Abstract] [Full Text] [PDF]

				N. Sharma, I. C. Okere, M. K. Duda, D. J. Chess, K. M. O'Shea, and W. C. Stanley Potential impact of carbohydrate and fat intake on pathological left ventricular hypertrophy Cardiovasc Res, January 15, 2007; 73(2): 257 - 268. [Abstract] [Full Text] [PDF]

				B. P. Ander, C. Hurtado, C. S. Raposo, T. G. Maddaford, J. F. Deniset, L. V. Hryshko, G. N. Pierce, and A. Lukas Differential sensitivities of the NCX1.1 and NCX1.3 isoforms of the Na+-Ca2+ exchanger to {alpha}-linolenic acid Cardiovasc Res, January 15, 2007; 73(2): 395 - 403. [Abstract] [Full Text] [PDF]

				O. A. Gudbrandsen, M. Hultstrom, S. Leh, L. Monica Bivol, O. Vagnes, R. K. Berge, and B. M. Iversen Prevention of Hypertension and Organ Damage in 2-Kidney, 1-Clip Rats by Tetradecylthioacetic Acid Hypertension, September 1, 2006; 48(3): 460 - 466. [Abstract] [Full Text] [PDF]

				M. Iraz, H. Erdogan, B. Ozyurt, F. Ozugurlu, S. Ozgocmen, and E. Fadillioglu Omega-3 Essential Fatty Acid Supplementation and Erythrocyte Oxidant/Antioxidant Status in Rats Ann. Clin. Lab. Sci., April 1, 2005; 35(2): 169 - 173. [Abstract] [Full Text] [PDF]

				F. Mies, V. Shlyonsky, A. Goolaerts, and S. Sariban-Sohraby Modulation of epithelial Na+ channel activity by long-chain n-3 fatty acids Am J Physiol Renal Physiol, October 1, 2004; 287(4): F850 - F855. [Abstract] [Full Text] [PDF]

				H.-H. Wang, T.-M. Hung, J. Wei, and A.-N. Chiang Fish oil increases antioxidant enzyme activities in macrophages and reduces atherosclerotic lesions in apoE-knockout mice Cardiovasc Res, January 1, 2004; 61(1): 169 - 176. [Abstract] [Full Text] [PDF]

				Y. V. Yuan and D. D. Kitts Dietary (n-3) Fat and Cholesterol Alter Tissue Antioxidant Enzymes and Susceptibility to Oxidation in SHR and WKY Rats J. Nutr., March 1, 2003; 133(3): 679 - 688. [Abstract] [Full Text] [PDF]

				D. A. Yahia, S. Madani, E. Prost, J. Prost, M. Bouchenak, and J. Belleville Tissue Antioxidant Status Differs in Spontaneously Hypertensive Rats Fed Fish Protein or Casein J. Nutr., February 1, 2003; 133(2): 479 - 482. [Abstract] [Full Text] [PDF]

				D. Ye, D. Zhang, C. Oltman, K. Dellsperger, H.-C. Lee, and M. VanRollins Cytochrome P-450 Epoxygenase Metabolites of Docosahexaenoate Potently Dilate Coronary Arterioles by Activating Large-Conductance Calcium-Activated Potassium Channels J. Pharmacol. Exp. Ther., November 1, 2002; 303(2): 768 - 776. [Abstract] [Full Text] [PDF]

				C. Triboulot, A. Hichami, A. Denys, and N. A. Khan Dietary (n-3) Polyunsaturated Fatty Acids Exert Antihypertensive Effects by Modulating Calcium Signaling in T Cells of Rats J. Nutr., September 1, 2001; 131(9): 2364 - 2369. [Abstract] [Full Text] [PDF]

				W. E. Hardman, C. P. R. Avula, G. Fernandes, and I. L. Cameron Three Percent Dietary Fish Oil Concentrate Increased Efficacy of Doxorubicin Against MDA-MB 231 Breast Cancer Xenografts Clin. Cancer Res., July 1, 2001; 7(7): 2041 - 2049. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Frenoux, J.-M. R. Articles by Prost, J. L. Search for Related Content PubMed PubMed Citation Articles by Frenoux, J.-M. R. Articles by Prost, J. L.