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PubMed1992

Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men and women.

To compare the effects of dietary palmitic acid (16:0) vs oleic acid (18:1) on serum lipids, lipoproteins, and plasma eicosanoids, 33 normocholesterolemic subjects (20 males, 13 females; ages 22-41 years) were challenged with a coconut oil-rich diet for 4 weeks. Subsequently they were assigned to either a palm olein-rich or olive oil-rich diet followed by a dietary crossover during two consecutive 6-week periods. Each test oil served as the sole cooking oil and contributed 23% of dietary energy or two-thirds of the total daily fat intake. Dietary myristic acid (14:0) and lauric acid (12:0) from coconut oil significantly raised all the serum lipid and lipoprotein parameters measured. Subsequent one-to-one exchange of 7% energy between 16:0 (palm olein diet) and 18:1 (olive oil diet) resulted in identical serum total cholesterol (192, 193 mg/dl), low-density lipoprotein cholesterol (LDL-C) (130, 131 mg/dl), high-density lipoprotein cholesterol (HDL-C) (41, 42 mg/dl), and triglyceride (TG) (108, 106 mg/dl) concentrations. Effects attributed to gender included higher HDL in females and higher TG in males associated with the tendency for higher LDL and LDL/HDL ratios in men. However, both sexes were equally responsive to changes in dietary fat saturation. The results indicate that in healthy, normocholesterolemic humans, dietary 16:0 can be exchanged for 18:1 within the range of these fatty acids normally present in typical diets without affecting the serum lipoprotein cholesterol concentration or distribution. In addition, replacement of 12:0 + 14:0 by 16:0 + 18:1, but especially 16:0 or some component of palm olein, appeared to have a beneficial impact on an important index of thrombogenesis, i.e., the thromboxane/prostacyclin ratio in plasma.

Adult↗
PubMed1987

The effects of bovine serum albumin and oleic acid on rat pancreatic lipase and bovine milk lipoprotein lipase.

The effects of bovine serum albumin on rat pancreatic lipase and bovine milk lipoprotein lipase were studied in a system of triacylglycerol emulsions stabilized by 1 1 mg/ml albumin. At concentrations greater than 1 mg/ml, albumin inhibited the activity of pancreatic lipase and interfered with enzyme binding to emulsified triacylglycerol particles. These effects could be countered by occupying five fatty acid binding sites on albumin with oleic acid. Following an initial lag period which increased with albumin concentrations, enzyme activity escaped from inhibition presumably due to saturation of fatty acid sites on albumin with oleic acid. Pancreatic lipase was active at 1 mg/ml albumin and 1 mM emulsion-bound oleic acid in the system. The effects of albumin on lipoprotein lipase were diametrically opposed to the above; enzyme activity was completely inhibited by 0.1 mM oleic acid, it increased with increasing fatty acid-free albumin concentrations and decreased as the fatty acid sites on albumin were filled. At 1 mM oleic acid and no added albumin the enzyme failed to bind at the oil water interface, whereas fatty acid-free or saturated albumin had no effect on binding. It is concluded that if the inhibition of pancreatic lipase by albumin is due to the inaccessibility of the enzyme to an oil-water interface blocked by denatured albumin, then albumin saturated with oleic acid would seem to be protected from unfolding at the interface and more readily displaced by the lipase. Pancreatic lipase and lipoprotein lipase, although sharing a number of common features, are distinct enzymes both functionally and mechanistically.

Animals↗
PubMed1982

Peripheral nerve cells in culture rich in Schwann cells incorporate and metabolize trans-unsaturated fatty acid (elaidic acid) as well as physiological dis isomer (oleic acid).

A culture of peripheral nerve cells enriched in Schwann cells was obtained from sciatic nerve in normal and demyelinating trembler mutant. These cells incorporated and metabolized a non-physiological trans fatty acid (elaidic aid) as well as the physiological cis isomer (oleic acid). Both acids were incorporated similarly in all lipids studied (phosphatidylcholine was a very potent acceptor) only cholesterol-esters' formation was slightly reduced from elaidic acid. Both acids were partially degradates into sub-units, in turn used for synthesis of new fatty acids. However elaidic acid was less degraded by the cells thus providing more C14:1, C16:1 fatty acids and less cholesterol. The sub-units were also used to provide very long chains, saturated and mono-unsaturated; only synthesis of nervonic acid was at variance when using oleic and elaidic acids. The presence of elaidic acid diminished the elongation-desaturation of essential fatty acids. No major differences were found between control and trembler cells, however cholesterol-esters' synthesis was slightly enhances in the mutant cells, when using both acids.

Animals↗
PubMed1984

Effects of oleic acid on pulmonary capillary leak and thromboxanes.

The role of arachidonic acid metabolites in oleic acid-induced lung injury in anesthetized dogs was investigated. Oleic acid was administered as a bolus injection into the pulmonary artery in the following dose sequence: 0.05, 0.10, and 0.20 ml/kg at 30, 60, and 120 min, respectively, after either indomethacin (10 mg/kg iv) or vehicle. A control group (n = 3) received normal saline instead of oleic acid. Measurements of hemodynamic parameters, mean systemic (MAP), pulmonary capillary wedge, and pulmonary artery pressures (PAP), cardiac output, arterial blood gases, extravascular lung waters (EVLW) by thermaldye double indicator dilution techniques and plasma immunoreactive thromboxane B2 ( iTxB2 ), by radioimmunoassay were obtained at zero time (baseline) and 20 min following each oleic acid injection. A new noninvasive technique was employed to measure pulmonary capillary protein leak by the scintigraphic analysis of intravenously administered technetium-99m radiolabeled human serum albumin ( 99mTc -HSA) in the cardiac and lung regions. Oleic acid injection caused a significant dose related fall in MAP (P less than 0.0002), arterial pO2 (P less than 0.0001), and cardiac output (P less than 0.001), and increases in EVLW (P less than 0.003) and plasma iTxB2 (P less than 0.02) in the vehicle pretreated animals, while mean PAP remained unchanged. In contrast, in the indomethacin pretreated dogs, MAP, EVLW, cardiac output, and plasma iTxB2 levels did not change from baseline values and there was an increase in mean PAP. Pulmonary vascular resistance was significantly elevated (P less than 0.05) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Lactational responses of dairy cows to diets containing regular and high oleic acid sunflower seeds.

Ten Holstein cows were used in a 15-wk nested factorial to evaluate the response to diets containing added fat from sunflower seeds high (greater than 65%) in linoleic acid (regular sunflower seeds) or high (80%) in oleic acid (high oleic acid variety sunflower seeds). Replicated periods were of 5 wk each, with data collected the last 3 wk of each period. Total mixed diets were 40% corn silage (DM basis), 15% alfalfa hay, and 45% concentrate mix. Concentrate mixes were control, 20% regular sunflower seeds, or 20% high oleic acid sunflower seeds in place of portions of the corn and soybean meal. Yields of milk (27.9, 25.4, and 28.8 kg/d) were similar for all diets, while 4% FCM (24.0, 19.2, and 24.0 kg/d) and SCM (24.8, 20.2, and 24.8 kg/d) were lower when cows were fed regular sunflower seeds. Percentages of fat (3.14, 2.43, and 2.92%) were reduced when cows were fed regular sunflower seeds, but protein (3.00, 3.24, and 3.03%) and total solids (12.12, 11.34, and 11.82%) were similar for all diets. Milk fat from cows fed regular sunflower seeds contained the highest proportions of unsaturated fatty acids with the lowest proportions from cows fed the control diet. Dry matter intakes (22.8, 20.6, and 21.9 kg/d) were similar. Molar percentages of ruminal acetate were lower and propionate higher when cows were fed regular sunflower seeds than when fed high oleic acid sunflower seeds or control. The fatty acid composition of dietary fat influenced the fatty acid composition of cows milk.

Animals↗
PubMed1988

Synthesis and contents of pancreatic exportable enzymes. Effect of oleic acid intraduodenal administration.

The effect of intraduodenal oleic acid administration on protein synthesis and enzymatic levels in rat pancreas was investigated. Sprague-Dawley rats were sacrificed at 20, 40, 60, and 80 min after intraduodenal oleic acid administration. Ten minutes before sacrifice, the rats were injected with 50 microCi 3H-Phenylalanine intraperitoneally. Amylase (Am), chymotrypsinogen (Chtg), trypsinogen (Tg) and lipase (Li) activities, and 3H-Phenylalanine incorporation to total secretory proteins were determined in pancreas homogenates. Forty minutes after oleic acid administration, the activities of Chtg, Tg and Li were significantly increased (45, 38 and 23%, respectively) above those from control rats. Amylase levels were not modified. Enzyme activities decreased below baseline levels by 60 and 80 min after oleic acid administration. The 3H-phenylalanine incorporation pattern exhibited a peak at 40 min. We conclude that intraduodenal oleic acid administration stimulates intrapancreatic enzyme content in a non-parallel fashion, before enzyme activities decreased below those from control rats. Protein synthesis was similarly affected by intraduodenal oleic acid.

Amylases↗
PubMed1981

[Intestinal lymphatic absorption of labelled oleic acid in the normal rat and rat treated with actidione-cycloheximide or acetoxycycloheximide].

Actidione-cycloheximide or acetoxycycloheximide treated and control Rats prepared with main mesenteric lymph duct cannulation were infused with a 90 mumol lipid emulsion composed of an equimolar mixture of monopalmitin, palmitic acid and 14C oleic acid and added with bile. In control Rats 75% of 14C oleic was recovered in lymph instead of 4,5% in treated rats. Although a low amount of lipids was concerned in this experiment, actidionecycloheximide and acetoxycycloheximide strongly inhibit intestinal absorption of oleic acid in lymph.

Animals↗
PubMed1986

Factors affecting perfusion distribution in canine oleic acid pulmonary edema.

Factors affecting perfusion distribution in oleic acid pulmonary edema were examined in 28 anesthetized open-chest dogs. Sixteen had unilobar oleic acid edema produced by left lower lobe pulmonary artery infusion of 0.03 ml/kg of oleic acid, and 12 had the same amount of edema produced by left lower lobe endobronchial instillation of hypotonic plasma. Lobar perfusion (determined from flow probes) and lobar shunt (determined from mixed venous and lobar venous blood) were measured at base line, 1.5 h after edema, and 10 min after 10 cmH2O positive end-expiratory pressure (PEEP). Fourteen dogs (8 oleic acid, 6 plasma) received sodium nitroprusside (11.72 +/- 7.10 micrograms X kg-1 X min-1). Total and lobar shunts increased to the same extent in all animals. Lobar perfusion decreased by 49.8 +/- 4.8% without nitroprusside and 34.0 +/- 3.6% with nitroprusside in the oleic acid group, corresponding values being 40.3 +/- 0.8% and 26.4 +/- 1.7% in the hypotonic plasma group. PEEP returned perfusion and shunt to base line. In oleic acid edema, most of the decreased perfusion results from mechanical effects of the edema, a smaller fraction results from other vascular effects of the oleic acid, and approximately 30% is reversible by nitroprusside. PEEP normalizes the perfusion distribution.

Animals↗
PubMed1985

Sequential cardiopulmonary changes after oleic-acid injury in dogs.

Oleic acid (OA) administered to experimental animals increases pulmonary vascular permeability and produces a condition that pathophysiologically resembles adult respiratory distress syndrome (ARDS) in humans. The present study examined the sequence of cardiorespiratory changes after OA infusion and their similarity to ARDS. After a baseline period, mechanically ventilated and anesthetized dogs were administered 0.18 ml/kg body weight OA into the pulmonary artery while hemodynamic and respiratory changes were monitored. After OA infusion, cardiac output fell by 39%, paralleling a 26% decrease in heart rate. Pulmonary vascular resistance (PVR) increased over 200% without a change in pulmonary capillary wedge pressure and initially without an increase in pulmonary artery pressure (PAP). Within 30 min after OA infusion, dynamic pulmonary compliance (Cdyn) was reduced 32% from baseline values, with a coincident increase in the alveolar-arterial PO2 gradient (P[A-a]O2) but without a significant change in the pulmonary shunt fraction (Qsp/Qt). This was followed in 30 min by a further 27% decrease in Cdyn, with a Qsp/Qt in excess of 50%. Both the hematocrit and hemoglobin concentration increased progressively after OA infusion, without a change in plasma protein concentration. The results suggest that the sequence of cardiopulmonary changes after OA injury are initially marked by a decrease in Cdyn and an increase in PVR and P(A-a)O2. This is followed by an increase in Qsp/Qt, PAP, hemoglobin concentration and PCO2. The changes appear related to progressive flooding of the alveolar air space with edema fluid. These findings parallel the sequential cardiorespiratory changes reported to occur in ARDS.

Animals↗
PubMed2002

Microbial biohydrogenation of oleic acid to trans isomers in vitro.

Ruminant products are significant sources of dietary trans fatty acids. Trans fatty acids, including various conjugated linoleic acid isomers, have been shown to act as metabolic modifiers of lipid metabolism. Trans fatty acids originate from biohydrogenation of dietary unsaturated fatty acids by gut microbes; however, the exact synthetic pathways are unclear. It was our goal to examine the biohydrogenation pathway for oleic acid, where oleic acid is hydrogenated directly to stearic acid. Our objective in this study was to trace the time course of appearance of 13C in labeled oleic acid to determine if trans monoenes are formed from the 13C-labeled oleic acid or if the 13C appears only in stearic acid as described in reviews of earlier work. Enrichments were calculated from the mass abundance of 13C in major fatty acid fragments and expressed as a percentage of total carbon isotopomers. Significant 13C enrichment was found in stearic acid, oleic acid, trans-6, trans-7, and in all trans C18:1 in positions 9-16. We concluded that the biohydrogenation of oleic acid by mixed ruminal microbes involves the formation of several positional isomers of trans monoenes rather than only direct biohydrogenation to form stearic acid as previously described.

Animals↗
PubMed2006

Structural changes of alpha-lactalbumin induced by low pH and oleic acid.

The effects of low pH and oleic acid on conformation and association state of Ca2+-depleted bovine alpha-lactalbumin (apo-BLA) have been studied by electrospray ionization mass spectrometry, fluorescence spectroscopy, and circular dichroism. The experimental results demonstrate that two structurally distinct species exist in the conformational transition of apo-BLA induced by low pH. One species populates at pH 3.0 characterized as a monomeric molten globule state and the other accumulates at pH 4.0-4.5 which is a partially folded dimer. Oleic acid promotes the formation of the dimeric intermediate at pH 4.0 and 7.0, but increases the content of molten globule state remarkably at pH 3.0 compared with that in the absence of oleic acid, indicating that oleic acid at pH 3.0 plays a different role from those at pH 4.0 and 7.0. Our data provide insight into the mechanism of pH-dependent and oleic acid-dependent structural changes and oligomerization of alpha-lactalbumin, and will be helpful to the understanding of the apoptosis-inducing function of multimeric alpha-lactalbumin in which oleic acid is a necessary cofactor.

Animals↗
PubMed1986

Oleic acid lung injury in sheep.

Intravenous infusion of oleic acid into experimental animals causes acute lung injury resulting in pulmonary edema. We investigated the mechanism of oleic acid lung injury in sheep. In experiments with anesthetized and unanesthetized sheep with lung lymph fistulas, we measured pulmonary arterial and left atrial pressures, cardiac output, lung lymph flow, and lymph and plasma protein concentrations. We injured the lungs with intravenous infusions of oleic acid at doses ranging from 0.015 to 0.120 ml/kg. We found that oleic acid caused reproducible dose-related increases in pulmonary arterial pressure and pulmonary vascular resistance, arterial hypoxemia, and increased protein-rich lung lymph flow and extravascular lung water. The lung fluid balance changes were characteristic of increased permeability pulmonary edema. Infusion of the esterified fat triolein had no hemodynamic or lung fluid balance effects. Depletion of leukocytes with a nitrogen mustard or platelets with an antiplatelet serum had no effect on oleic acid lung injury. Treatment of sheep before injury with methylprednisolone 30 mg/kg or ibuprofen 12.5-15.0 mg/kg also had no effects. Unlike other well-characterized sheep lung injuries, injury caused by oleic acid does not require participation of leukocytes.

Animals↗
PubMed2000

Supplementation with long-chain n-3 fatty acids in non-insulin-dependent diabetes mellitus (NIDDM) patients leads to the lowering of oleic acid content in serum phospholipids.

BACKGROUND: The dietary supplementation with EPA (eicosapentaenoic acid; 20:5n3) and DHA (docosahexaenoic acid; 22:6n3) has been recommended because of their favourable effects on the cardiovascular system (including complications of NIDDM). Oleic acid (18:1n9) from olive oil has some analogous and complementary effects. Potential competitive relations between long-chain n-3 fatty acids (FAs) and the oleic acid would therefore mean a problem. AIM OF THE STUDY: We focused primarily on the oleic acid changes in serum phospholipids (SPL) after a supplementation with EPA and DHA. METHODS: Thirty-five patients with type 2 diabetes mellitus (NIDDM) were supplemented for 28 days with 1.7 g of EPA plus 1.15 g of DHA/day (as Maxepa capsules, Seven Seas, U. K.). After that, a 3-month wash-out control period with 21 patients followed. A fatty acid composition of serum phospholipids (SPL) was determined by capillary gas-chromatography. Values were calculated as relative percentages of all FAs. RESULTS: After the supplementation with the Maxepa capsules, there was a very strong increase in EPA, docosapentaenoic acid (22:5n3) and DHA content in SPL. It was followed by a strong decrease after the wash-out (all p < 0.0001). The oleic acid SPL content after the intervention significantly decreased from 10. 105 +/- 0.307% (mean +/- S. E. M.) to 9.082 +/- 0.276 % (p < 0.0003). During the wash-out, the change was in the opposite direction (p < 0.0001). When the intervention and the wash-out periods were taken together, changes in the oleic acid were inversely correlated with changes in EPA, docosapentaenoic acid and DHA (r = -0.729; r = -0.552; r = -0.629, respectively; p < 0.0001; n = 56). On the background of the overall n-6 FA reduction, the decline in the arachidonic acid after the supplementation (p < 0.0001) and its rise after the wash-out (p < 0.0003) were similar. There were no significant changes in the saturated FA spectrum. CONCLUSIONS: Supplementation with long-chain n-3 FAs in NIDDM patients leads to the lowering of oleic acid SPL content. Whereas the reduction of the arachidonic acid may have some desirable aspects (e. g. suppression of thromboxane TxA2 or 4 series leukotriene production), the decline of the former is to be regarded as a potential problem. Therefore, the search for optimally balanced blends of n-3 polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs) seems to be more promising than a supplementation with only one type of FA.

Cardiovascular Diseases↗
PubMed1987

Effect of linoleic and oleic acids on blood pressure, blood viscosity, and erythrocyte cation transport.

It has been proposed that dietary linoleic acid lowers blood pressure (BP) by being converted to arachidonic acid and prostanoids of the two-ene series. We tested the effects of linoleic acid on plasma arachidonic acid, blood pressure, blood viscosity, and RBC cation transport. Oleic acid, the major dietary monounsaturated fat and which is not a prostanoid precursor, was used as a control. Seventeen adults consumed 23 g/d of linoleic acid or oleic acid provided by genetic variants of safflower seed, each for 4 weeks in a double-blind crossover design. Linoleic and oleic acids were enriched significantly in the plasma cholesteryl esters, phospholipids and triglycerides during the respective periods of supplementation but there was no increase in arachidonate. Mean BP was 116.1/76.8 during ingestion of oleic and 113.6/74.6 during ingestion of linoleic acid (p = 0.09 systolic, p = 0.12 diastolic). The power of the study was over 75% for detecting a significant (p less than 0.05) effect of 4 mm Hg in systolic BP or diastolic BP. Whole blood and plasma viscosity, and RBC Li/Na countertransport, Na/K cotransport, and Na pump systems (Vmax) were unchanged during the protocol. Therefore, variations in dietary linoleic or oleic acids are unlikely to have major effects on BP or on several membrane-dependent erythrocyte functions related to hypertension.

Adult↗
PubMed1979

[Comparative oxidation of erucic and oleic acids by mitochondria isolated from heart auricle of living man].

Mitochondria were isolated from fragments of heart auricles, that were cut off during surgical intracardiac operations. They were incubated with either [14 14C] erucic acid or [10 14C] oleic acid as a control. In the experimental conditions used, the radioactive products soluble in perchloric acid, that are issued from the beta-oxidation reactions in mitochondria, were formed in much lower amounts from erucic acid than from oleic acid. These results show the very low capacity of human heart mitochondria to use directly erucic acid as a substrate for energy requirements, as has been observed before with other animal species. Activation of fatty acids, the preliminary step of their beta-oxidation, was also observed to be very much lower with erucic acid.

Adult↗
PubMed1996

Oleic acid uptake by jejunal and ileal rat brush border membrane vesicles.

In previous works, a membrane fatty acid transport system has been identified in brush border membrane vesicles, but no different intestinal regions were considered in these studies. To test the existence of a proximal-to-distal gradient of fat absorption along the small intestine, transmembrane influx kinetics of a representative long-chain fatty acid, 3H-oleic acid, in both jejunum and ileum of rat has been studied using brush border membrane vesicles (BBMV). With increasing concentration of unbound oleate in the medium, both jejunal and ileal BBMV showed saturable uptake kinetics (Vmax = 0.15 +/- 0.01 nmol.mg protein-1 x 5 min-1 and Km = 136 +/- 29.1 nmol for jejunum, and Vmax = 0.23 +/- 0.03 nmol.mg protein-1 x 5 min1 and Km = 196 +/- 50.3 nmol for ileum). These results support the hypothesis that oleic acid uptake occurs via a carrier-mediated transport mechanism in both jejunum and ileum. Furthermore, the existence of a proximal-to-distal gradient for fat absorption was apparent with a higher density of transport units (Vmax) in ileum compared to jejunum.

Animals↗