Javier S. Perona

Abstract The effects of fatty acids, triacylglycerol and some minor components of olive oils on parameters related to cardiovascular disease are discussed. these parameters include plasma lipids, blood pressure, postprandial lipaemia and immunoinflammatory reactions.

This study was designed to determine the composition of postprandial triglyceride-rich lipoproteins (TRL) after the intake of pomace olive oil (POO), which is a subproduct of the extraction of virgin olive oil (VOO) and presents a high concentration of minor components with biological activity. Meals enriched in POO and refined olive oil (ROO) were administrated to 9 healthy young men and blood was extracted every hour during a postprandial period of 7 hours. Serum and TRL lipid composition were measured by enzymatic and chromatographic methods and apolipoprotein B composition by SDS-PAGE. POO and ROO showed a very similar fatty acid composition but differed in their unsaponifiable fraction. The content of phytosterols, tocopherols, terpenic acids and alcohols and fatty alcohols was much higher in POO than in ROO. Serum lipids were not affected by the administration of the oils but the triglyceride concentration in TRL and the size of the particles (p < 0.05) after POO was higher at time point 2 h and lower at time point 4 h compared with ROO. In contrast, the number of TRL particles was lower after POO, although the rate of clearance was similar. We suggest that the unsaponifiable fraction between the two olive oils affect the size and composition of postprandial TRL, which might have a relevant impact on their atherogenicity.

Hypertension development in the spontaneously hypertensive rat (SHR) leads to vascular wall widening by smooth muscle cell proliferation. In these cells, triglycerides (TG) and cholesteryl esters (CE) can accumulate until they become foam cells. We administrated two oleic rich oils, virgin olive (VOO) and high oleic sunflower oils (HOSO), to Wistar-Kyoto rats (WKY) and SHR because these oils have been reported to reduce the risk for coronary heart disease in hypertensive patients and SHR. After 12 weeks of feeding, we analyzed the TG and CE composition and the lipolytic (lipoprotein lipase, LPL, and non-LPL) activity in aortas of these animals. HOSO increased the content of linoleic acid in CE and TG of aortas from both WKY and SHR as compared with animals fed VOO by proportionally decreasing the content of oleic acid. Conversely, VOO reduced the LPL and non-LPL lipolytic activities, hence limiting the free fatty acids available for the synthesis of TG and CE in the vascular wall.

Genetic hypertension is associated with alterations in lipid metabolism, membrane lipid composition and membrane-protein function. 2-Hydroxyoleic acid (2OHOA) is a new antihypertensive molecule that regulates the structure of model membranes and their interaction with certain peripheral signalling proteins in vitro. While the effect of 2OHOA on elevated blood pressure is thought to arise through its influence on signalling proteins, its effects on membrane lipid composition remain to be assessed. 2OHOA administration altered the lipid membrane composition of hypertensive and normotensive rat plasma membranes, and increased the fluidity of reconstituted liver membranes from hypertensive rats. In spontaneously hypertensive rats (SHR), treatment with 2OHOA increased the cholesterol and sphingomyelin content while decreasing that of phosphatidylserine-phosphatidylinositol lipids. In addition, monounsaturated fatty acid levels increased as well as the propensity of reconstituted membranes to form HII-phases. These data suggest that 2OHOA regulates lipid metabolism that is altered in hypertensive animals, and that it affects the structural properties of liver plasma membranes in SHR. These changes in the structural properties of the plasma membrane may modulate the activity of signalling proteins that associate with the cell membrane such as the Galphaq/11 protein and hence, signal transduction.

Abstract Triglyceride composition of rat liver was analyzed by HPLC with a non-linear elution gradient of acetone in acetonitrile using a light-scattering detector. Triglyceride molecular species were predicted by means of simple and multiple linear regression analysis ...

Rats fed with a fat-free or an olive oil-rich diet were employed to compare the response of two chromatographic techniques in the determination of rat liver triglyceride (TG) molecular species composition. Gas-liquid chromatography (GLC) on polarizable liquid phase and reversed-phase high-performance liquid chromatography (RP-HPLC) have been commonly employed for TG analysis, obtaining a similar number of chromatographic peaks when used for animal tissue TG determination. In the present study similar results were achieved with regard to most relevant chromatographic peaks, however, important differences were found in the content of minor TGs. Indeed, RP-HPLC permitted separation of long chain polyunsaturated fatty acids, which were not detected by GLC, while the latter technique reported a higher number of myristoyl-containing TG species. RP-HPLC analysis reported a greater number of TGs, with more similarity to a random composition, made up from the liver fatty acid composition. Therefore, it was concluded that utilization of both techniques would be helpful for liver TG analysis as the use of only one of them does not provide a complete profile of liver TGs. Nevertheless RP-HPLC seems to be more useful for this purpose since revealed a more extensive profile.

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In contrast to other metabolic functions, the role of dietary antioxidants and oil on microsomal lipid oxidation has been less extensively studied. This study examines ascorbate-Fe2+ and NADPH-induced lipid peroxidation of hepatic microsomes of rats that were fed for three ...

Minor components of virgin olive oil (VOO) may play a key role in the beneficial effects of VOO on atherosclerosis. In the present study we evaluated the influence of the unsaponifiable fraction of VOO on the production of eicosanoids and nitric oxide (NO) by endothelial cells (HUVECs). Triglyceride-rich lipoprotein (TRLs) were isolated from human serum after the intake of meals enriched in 3 high-oleic acid oils, i.e., high-oleic sunflower (HOSO), VOO, or enriched-virgin olive (EVO) oils, the last-mentioned containing 2.4% of unsaponifiable matter. HOSO induced a greater accumulation of triglycerides (TGs) in the postprandial serum than VOO or EVO, as measured by calculating the area under the curve. The incubation with TRLs increased NO release by endothelial cells compared with untreated control cells, but the effects of the various TRLs did not differ. EVO-derived TRLs reduced the production of prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TxB(2)) (the stable metabolite of TxA(2)) compared with VOO- or HOSO-derived TRLs. The release of PGI(2) (as 6-keto PGF(1alpha)) was similarly diminished by all TRLs compared with the control. In conclusion, the unsaponifiable fraction of VOO does not affect postprandial triglyceridemia, but it has favorable effects on endothelial function, mainly by reducing proinflammatory and vasoconstrictor eicosanoid synthesis (PGE(2) and TxB(2)).

There is currently a considerable amount of interest in the benefits of certain dietary elements, and in particular of olive oil, in endothelial function and thus in hypertension. "Orujo" or pomace olive oil is obtained from the residues of the olive by a novel centrifugation process, and it is a good dietary source of triterpenic compounds such as oleanolic and maslinic acid, erythrodiol, and uvaol. Until now, there was no information available regarding the properties of these triterpenoids on the vasculature of hypertensive animals. However, in this in vitro study, we have analyzed the vasorelaxation induced by these triterpenoids in isolated aorta from spontaneously hypertensive rats (SHR). The triterpenoids tested induced concentration-dependent vasorelaxation, mostly involving nitric oxide (NO). Indeed, the responses were attenuated by removal of the endothelium or following pretreatment with the NO synthase inhibitor L-NAME. Furthermore, the differences that were observed in the potency of relaxation, the selectivity, and the dependence on the endothelium were attributed to structural features of the triterpenoids. In conclusion, triterpenic components in pomace olive oil induce vasorelaxation of the aorta from SHR, and this effect generally involves endothelial NO.