The role of linoleic acid and its metabolites in the lowering of plasma cholesterol and the prevention of cardiovascular disease

Cytotoxicity, anti-inflammatory effect, and acute oral toxicity of a novel Attalea phalerata kernel oil-loaded nanocapsules

The kernel oil of the Attalea phalerata Mart. Ex Spreng (Acurí) is traditionally used in several Latin American countries to treat respiratory problems, inflammation, and fever. However, it cannot be found on the literature any attend to use this oil in pharmaceutical formulation. In this paper, it was developed Acurí oil-loaded nanocapsules, and it was evaluated the cytotoxicity against cancer cells, the antinflammatory activity and the oral acute toxicity in rats. Acurí oil contains lauric acid as the predominant saturated fatty acid (433.26 mg/g) and oleic acid as the main unsaturated fatty acid (180.06 mg/g). The Acurí oil-loaded nanocapsules showed a size of 237 nm, a polydispersity index of 0.260, and a high ζ-potential of -78.75 mV. It was obtained an encapsulation efficiency of 88.77%, and the nanocapsules remain stable on the shelf for 180 days. The nanocapsules showed a rapid release profile (98.25% in 40 minutes). Nanocapsules at a dose of 10 mg/kg exhibit an anti-inflammatory effect similar to indomethacin at the same dose. The nanocapsules showed excellent antiproliferative effect and selectivity index against prostate tumor cells (IC50 2.09 µg/mL, SI=119.61) and kidney tumor cells (IC50 3.03 µg/mL, SI=82.50). Both Acurí oil and Acurí oil-loaded nanocapsules are nontoxic at a dose of 2000 mg/kg. Additionally, they reduce serum triglyceride and total cholesterol levels in rat and could find application in nutraceutical formulations. The Acurí oil-loaded nanocapsules emerge as a promising candidate for new antitumor therapies.

Dietary palm oil enhances Sterol regulatory element-binding protein 2-mediated cholesterol biosynthesis through inducing endoplasmic reticulum stress in muscle of large yellow croaker (Larimichthys crocea)

Sterol regulatory element-binding protein 2 (SREBP2) is considered to be a major regulator to control cholesterol homoeostasis in mammals. However, the role of SREBP2 in teleost remains poorly understand. Here, we explored the molecular characterisation of SREBP2 and identified SREBP2 as a key modulator for 3-hydroxy-3-methylglutaryl-coenzyme A reductase and 7-dehydrocholesterol reductase, which were rate-limiting enzymes of cholesterol biosynthesis. Moreover, dietary palm oil in vivo or palmitic acid (PA) treatment in vitro elevated cholesterol content through triggering SREBP2-mediated cholesterol biosynthesis in large yellow croaker. Furthermore, our results also found that PA-induced activation of SREBP2 was dependent on the stimulating of endoplasmic reticulum stress (ERS) in croaker myocytes and inhibition of ERS by 4-Phenylbutyric acid alleviated PA-induced SREBP2 activation and cholesterol biosynthesis. In summary, our findings reveal a novel insight for understanding the role of SREBP2 in the regulation of cholesterol metabolism in fish and may deepen the link between dietary fatty acid and cholesterol biosynthesis.

Differences in Absorption and Metabolism between Structured 1,3-Oleate-2-palmitate Glycerol and 1-Oleate-2-palmitate-3-linoleate Glycerol on C57BL/6J Mice

This study investigated differences in absorption and metabolism between 1,3-oleate-2-palmitate glycerol (OPO) and 1-oleate-2-palmitate-3-linoleate glycerol (OPL) using C57BL/6J mice. OPL was associated with higher postprandial plasma total triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C) concentrations, and the ratio of LDL-C to high-density lipoprotein cholesterol (HDL-C) compared to those of OPO (p > 0.05). OPO significantly increased postprandial oleic acid (OA) concentrations compared to OPL over the entire monitoring period (p < 0.05), while OPL significantly elevated linoleic acid (LA) levels compared to OPO (p < 0.05). After 1 month of feeding, the mice in both OPO and OPL groups showed lower final weight, weight gain, and liver TG, LDL-C, and LDL/HDL concentrations compared to the control (soybean oil) group. Lipidomics results showed that OPO increased the biosynthesis of very long-chain fatty acids and decreased the abundance of AcCa (16:1), AcCa (18:2), AcCa (18:1), AcCa (16:0), CarE (16:0), and CarE (16:1) relative to OPL. These lipid metabolites were positively correlated with liver TG, LDL-C, and LDL/HDL levels and negatively related to peroxisome proliferator-activated receptors α (PPARα) and acyl-CoA oxidase (ACOX1) expression. This study showed differences in physiologic functions between OPO and OPL and provided support for the future application of OPL in infant formula.

An investigation of the growth status of 19-year-old Idesia polycarpa 'Yuji' plantation forest in the mountainous region of Henan, China

Plantation forests play an important role in the mitigation of greenhouse gas emissions. Idesia polycarpa Maxim is an emerging woody oil tree species in most Asian countries. The 19-year-old Idesia polycarpa 'Yuji' plantation forest was selected as a sample site. The nutrient contents of the understory soil total carbon (TC), total nitrogen (TN), nitrate nitrogen (NN), organic carbon (OC), available phosphorus (AP), available potassium (AK), and pH were analyzed. Several metrics were measured to quantify the growth status of the forest, such as tree heights (H), clear bole heights (CBH), diameters at breast height (DBH), and male-to-female ratios (MFR). In addition, we harvested the fruits to analyze oil content and fatty acid composition. The results found that the nutrient content of the soil was TC (4.93%), TN (0.42%), NN (43.08 mg kg-1), OC (4.90 g kg-1), AP (13.66 mg kg-1), AK (30.48 mg kg-1), and pH (7.90). The growth characteristics were H (11.75 m), DBH (12.79 cm), and CBH (6.17 m). The MFR was close to 1:1. Besides, the oil content of the fruit and unsaturated fatty acids was 24.08% and 68.49%, respectively. As an alternative tree species, the plantation of Idesia polycarpa offers great potential in artificial afforestation in some particular places with specific forest site conditions.

Green extraction of carotenoids from apricot flesh by ultrasound assisted corn oil extraction: Optimization, identification, and application

The valorization of waste apricot flesh (WAF) can solve environmental and economic problems, and also meets the demand for natural pigments. Therefore, the aim of this paper was to recover carotenoids from WAF, to determine the type and content of carotenoids in the extracts and to explore the potential of the extracts for food industry applications. The extraction conditions were optimized. The total carotenoids content (TCC) was 42.75 mg/100 g dried weight under the optimized conditions: Time: 60 min, Temperature: 41.53℃, Power: 200 W, Liquid to solid (LS) ratio: 0.10 g/mL. The highest content of carotenoids in the corn oil extracts (COE) was phytoene. Color of COE under high temperature was investigated. Carotenoids in the COE were degraded at high temperatures. The a* of fries fried by COE was 7.31 times higher than that of corn oil. This study provides guidance for the green recovery of carotenoids and valorization of WAF.

Exploring the effect of Crinum latifolia in obesity: possible role of oxidative, angiogenic, and inflammatory pathways

Obesity is a multifaceted disease encompassing deposition of an unnecessary amount of fat which upsurges the possibility of other complications, viz., hypertension and certain type of cancers. Although obesity results from combination of genetic factors, improper diet and inadequate physical exercise also play a major role in its onset. The present study aims at exploring the anti-obesity activity of Crinum latifolia leaf extract in obese rats. The leaves were extracted using hydroalcoholic extraction which was later diluted with water and given to obese rats. The dosing was started from the 4^th week (by oral administration of extract of Crinum latifolia (100 mg/kg and 200 mg/kg) and combination of Crinum latifolia leaf extract 200 mg/kg and orlistat 30 mg/kg) till the 10^th week. Various angiogenic, antioxidant, biochemical, and inflammatory biomarkers were assessed at the end of the study. The obese symptoms were progressively reduced in treatment groups when compared to disease control groups. The angiogenic parameters and inflammatory parameters were consequently reduced in treatment groups. The oxidative parameters superoxide dismutase (SOD) and catalase were gradually increased, while levels of TBARS were reduced in treatment groups showing antioxidant nature of leaf hydroalcoholic extract. The Crinum latifolia leaf extract possesses anti-obesity properties and therefore can be used as a therapeutic option in the management of obesity.

Predictive serum biomarkers of patients with cerebral infarction

OBJECTIVES

Stroke is the third most common cause of death and also causes seizures and disability. Biomarkers are abnormal signal indicators at the biological level that are present before the organism is seriously affected and are more sensitive to early diagnosis than are traditional imaging methods. Early diagnosis of stroke can prevent the progression of the disease. However, there are currently no widely accepted biomarkers for stroke that have been applied clinically.

METHODS

A serum metabonomics method based on ultra-high-performance liquid chromatography-quadrupole-time of flight tandem mass spectrometry (UPLC-Q-TOF/MS) was used to identify potential biomarkers and metabolic pathways of cerebral infarction. The receiver-operating characteristic (ROC) curve was used to verify the diagnostic and classification abilities of the biomarkers, and a support vector machine (SVM) model was developed for the prediction of cerebral infarction.

RESULTS

Principal component analysis revealed a clear separation between the normal and cerebral infarction groups. A total of 13 potential serum biomarkers were identified, which were mainly involved in linoleic acid metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis; tyrosine metabolism; arachidonic acid metabolism; and fatty acid biosynthesis. The ROC curve analysis showed that the potential biomarkers had high specificity and sensitivity for the diagnosis of cerebral infarction. The SVM model had good diagnostic ability and could accurately distinguish the control group from the cerebral infarction group.

DISCUSSION

The metabonomics approach may be a useful bioanalytical method for understanding the pathophysiology of cerebral infarction and may provide an experimental basis for the development of clinical biomarkers for stroke.

Exploring the mechanism of TCM formulae in the treatment of different types of coronary heart disease by network pharmacology and machining learning

Traditional Chinese medicine (TCM) has long been used in the clinical treatment of coronary heart disease (CHD). TCM is characterized by syndrome-based medication, which is, using different TCM formulae for different syndromes. However, the underlying mode of action remains unclear. In this work, we utilized network pharmacology and machine learning to explore the mechanism of eight classic TCM formulae in the treatment of different types of CHD. First, by integrating multiple databases, a total of 669 potential bioactive compounds and 581 targets of the eight formulae were screened. Then, the effectiveness of these formulae on CHD was evaluated using two network-based indicators. The results showed that each formula's targets were significantly correlated with CHD associated genes and overlapped with the targets of 9 classes of drugs for cardio vascular diseases (CVD) to some degree. Next, from 5 different levels, i.e., herb, symptom, compound, target, and pathway level, we systematically compared the eight formulae using network clustering and hierarchical clustering. We found that all the formulae could be grouped into five clusters and the clustering results were approximately consistent at different levels. All the formulae were involved in 7 pathways closely related to CHD and may exhibit the common effect of relieving angina. Formulae in the same group collectively regulated some unique pathways and suggest further specific indications. For example, the three formulae used for Qi stagnation and blood stasis, Qi deficiency and blood stasis, and Qi-Yin deficiency syndromes acted on two special pathways (TNF signaling pathway, NF-kappa B signaling pathway) and may exert anti-inflammatory and immune-enhancing effects; the two formulae for Yin deficiency of heart and kidney, and Yang deficiency of heart and kidney syndromes regulated two special pathways (PPAR signaling pathway, thyroid hormone signaling pathway) in endocrine system and could improve renal function. Subsequently, we designed a rank algorithm, which integrated network topology with biological function, to identify important targets of these formulae. The results were consistent with the multi-level clustering results. At last, our literature mining validated about 20 % putative targets, as well as clustering results and effects of the formulae by experimental evidences. This study explained the medication patterns and scientific significance of TCM formulae on different types of CHD from perspective of systems biology. It may facilitate the understanding of different types of CHD described by traditional Chinese medicine from the perspectives of modern biology.

Potentials of truffles in nutritional and medicinal applications: a review

Truffles, the symbiotic hypogeous edible fungi, have been worldwide regarded as a great delicacy because of their unique flavor and high nutritional value. By identifying their bioactive components such as phenolics, terpenoids, polysaccharides, anandamide, fatty acids, and ergosterols, researchers have paid attention to their biological activities including antitumor, antioxidant, antibacterial, anti-inflammatory, and hepatoprotective activities. In addition, numerous factors have been investigating that can affect the quality and productivity of truffles to overcome their difficulty in culturing and preserving. To provide the information for their potential applications in medicine as well as in functional food, this review summarizes the relevant literature about the biochemical composition, aromatic and nutritional benefits, and biological properties of truffles. Besides, various factors affecting their productivity and quality as well as the preservation methods are also highlighted.

Ferreira I, M.S.M. Bastos M, Medeiros R, Gaivão I, Rosa E, Oliveira PA. Dietary Supplementation with Chestnut (Castanea sativa) Reduces Abdominal Adiposity in FVB/n Mice: A Preliminary Study

The production of chestnut (Castanea sativa Miller) is mostly concentrated in Europe. Chestnut is recognized by its high content of antioxidants and phytosterols. This work aimed to evaluate the effects of dietary chestnut consumption over physiological variables of FVB/n mice. Eighteen FVB/n male 7-month-old mice were randomly divided into three experimental groups (n = 6): 1 (control group) fed a standard diet; 2 fed a diet supplemented with 0.55% (w/w) chestnut; and 3 supplemented with 1.1% (w/w) chestnut. Body weight, water, and food intake were recorded weekly. Following 35 days of supplementation, the mice were sacrificed for the collection of biological samples. Chestnut supplementation at 1.1% reduced abdominal adipose tissue. Lower serum cholesterol was also observed in animals supplemented with chestnut. There were no significant differences concerning the incidence of histological lesions nor in biochemical markers of hepatic damage and oxidative stress. These results suggest that chestnut supplementation may contribute to regulate adipose tissue deposition.

Protective effects of aqueous extract from Gei Herba on blood-deficiency mice: insights gained by a metabolomic approach

With increasing tumor incidence, anemia (categorized as a blood deficiency in traditional Chinese medicine) caused by chemotherapy has become a major side effect worldwide. Gei Herba, a traditional Miao nation herb, has a prominent effect on the treatment of blood deficiency (BD). However, its application is limited owing to little fundamental research. Therefore, a GC-MS metabolomic approach was used to study the protective effect of aqueous extract from Gei Herba (AEG) on BD mice and its putative mechanism. In this study, 32 male mice were divided into four groups: a control group, a BD model group, and two groups subjected to AEG treatment at a daily dose of 0.15 or 0.30 g kg⁻¹ for 8 d. After AEG treatment, the HGB and HCT levels in the blood of BD mice were significantly increased, the activity of superoxide dismutase was increased, and the histomorphology of the liver was improved. Furthermore, compared with those in the model group, the levels of eight significant metabolites [phosphoric acid, glycine, l-proline, ribitol, (Z,Z)-9,12-octadecadienoic acid, oleic acid, uridine and 4B2H-carbamic acid] in the liver were significantly changed by AEG. The findings of this study provide sound evidence regarding the protective effects of AEG in BD mice from both classical and metabolomic perspectives. The mechanisms of action of AEG could be related to regulation of linoleic acid metabolism and that of glycine, serine, and threonine metabolism.

The protective effect and mechanism of Gei Herba in BD mice were revealed by classical and metabolomic perspectives.

Effects of chronic administration of arachidonic acid on lipid profiles and morphology in the skeletal muscles of aged rats

Arachidonic acid (20:4n-6, ARA) is a major component of the cell membrane, whereas ARA-derived eicosanoids are formed when cells are damaged. Aging is associated with an accretion of oxidative stress in skeletal muscles. In this study, we examined the effects of chronic administration (13 weeks) of ARA (240 mg/kg/day) on fatty acid composition, antioxidative status, and morphology of slow (soleus muscles) and fast (extensor digitorum longus muscles; EDL)-twitch muscles in aged rats (21 months old). The level of reactive oxygen species was higher in the EDL of ARA-administered rats than in that of control rats. ARA administration decreased the muscle cell volumes and increased the number of slow myosin heavy chain (MHC)-positive cells in the EDL. The relative content of MHC2X was increased whereas the relative content of MHC2B was decreased in the EDL of ARA-administered rats. These results suggest that ARA deposition in the fast-twitch muscle of aged rats reduced cell volume with an increase in oxidative stress.

Dietary medium chain fatty acid supplementation leads to reduced VLDL lipolysis and uptake rates in comparison to linoleic acid supplementation

Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and linoleic acid activates PPAR receptors. Both these mechanisms may modify lipoprotein and fatty acid metabolism after dietary intervention. Our objective was to investigate how dietary MCFA and linoleic acid supplementation and body fat distribution affect the fasting lipoprotein subclass profile, lipoprotein kinetics, and postprandial fatty acid kinetics. In a randomized double blind cross-over trial, 12 male subjects (age 51±7 years; BMI 28.5±0.8 kg/m²), were divided into 2 groups according to waist-hip ratio. They were supplemented with 60 grams/day MCFA (mainly C8:0, C10:0) or linoleic acid for three weeks, with a wash-out period of six weeks in between. Lipoprotein subclasses were measured using HPLC. Lipoprotein and fatty acid metabolism were studied using a combination of several stable isotope tracers. Lipoprotein and tracer data were analyzed using computational modeling. Lipoprotein subclass concentrations in the VLDL and LDL range were significantly higher after MCFA than after linoleic acid intervention. In addition, LDL subclass concentrations were higher in lower body obese individuals. Differences in VLDL metabolism were found to occur in lipoprotein lipolysis and uptake, not production; MCFAs were elongated intensively, in contrast to linoleic acid. Dietary MCFA supplementation led to a less favorable lipoprotein profile than linoleic acid supplementation. These differences were not due to elevated VLDL production, but rather to lower lipolysis and uptake rates.

The hypolipidaemic effects of Spirulina (Arthrospira platensis) supplementation in a Cretan population: a prospective study

BACKGROUND

Spirulina (Arthrospira platensis) is a filamentous cyanobacterium used as a food supplement. The objective of the study was to determine the lipid-lowering effects of Spirulina in Cretan Greek dyslipidaemic patients, and to document its effectiveness as a possible alternative treatment for dyslipidaemia. Fifty-two adultCretan outpatients (32 men, 20 women), median age 47 (range, 37-61) years, with recently diagnosed dyslipidaemia, consumed orally 1 g Spirulina (Greek production) per day for 12 weeks. The full lipid profile was measured in fasting blood samples at the beginning and end of the study period. Anthropometric measurements including systolic and diastolic blood pressure, height, weight and body mass index were also recorded.

RESULTS

At the end of the 3-month intervention period the mean levels of triglycerides, low density lipoprotein-cholesterol, total cholesterol, non-high density lipoprotein-cholesterol levels, and the ratio of total cholesterol to high-density lipoproteincholesterol were significantly decreased: 16.3% (P < 0.0001), 10.1% (P < 0.0001), 8.9% (P < 0.0001), 10.8% (P < 0.0001) and 11.5% (P = 0.0006) respectively, whereas the mean high-density lipoprotein-cholesterol levels were not significantly increased (3.5%). Blood pressure, weight and body mass index remained almost unchanged.

CONCLUSIONS

Spirulina supplementation at a dose of 1 g daily has powerful hypolipidaemic effects, especially on the triglyceride concentration in dyslipidaemic Cretan outpatients.

Different dietary fatty acids are associated with blood lipids in healthy South African men and women: the PURE study

BACKGROUND

Preliminary data from the baseline Prospective Urban Rural Epidemiology (PURE) study in South Africa indicated a higher prevalence of dyslipidemia than previous South African studies. The intake of specific individual dietary fatty acids may affect blood lipids differently than sub-groups of fat (i.e. polyunsaturated fatty acids). We investigated the dietary intake of different individual fatty acids and their associations with blood lipids, in relation to urbanization and gender.

METHODS

Cross-sectional data analysis within the PURE baseline study of healthy subjects (n=1950, 35-70 years) from rural and urban areas. Dietary data were collected and blood lipid analysis performed.

RESULTS

Intake of individual fatty acids was significantly higher in urban than rural dwellers. However, the intake of n-3 PUFAs was below recommendations in all groups. Total cholesterol and LDL were higher in females than in males, with no rural‒urban differences. Intake of alpha-linolenic acid (ALA) was positively associated with total cholesterol (β=0.143) and triglycerides (β=0.256) in males. The risk for having elevated LDL also increased with increased intake of ALA (OR 1.49, 95% CI 1.04, 2.14) in males. In females, arachidonic acid and eicosapentaenoic acid (EPA) were positively associated with total cholesterol and arachidonic acid was also positively associated with LDL, whereas docosahexaenoic acid was negatively associated with total cholesterol and LDL.

CONCLUSIONS

These results suggest that specific individual dietary fatty acids may affect blood lipids in males differently than in females irrespective of rural or urban dwelling. The positive association between ALA and total cholesterol and triglycerides in males is a concern, because current advice aims to improve the dietary linoleic acid to ALA ratio by increasing ALA intake.

LC-PUFA from photosynthetic microalgae: occurrence, biosynthesis, and prospects in biotechnology

Microalgae offer potential for numerous commercial applications, among them the production of long-chain polyunsaturated fatty acids (LC-PUFAs). These valuable fatty acids are important for a variety of nutraceutical and pharmaceutical purposes, and the market for these products is continually growing. An appropriate ratio of LC-PUFA of the ω-3 and ω-6 groups is vital for "healthy" nutrition, and adequate dietary intake has strong health benefits in humans. Microalgae of diverse classes are primary natural producers of LC-PUFA. This mini-review presents an introductory overview of LC-PUFA-related health benefits in humans, describes LC-PUFA occurrence in diverse microalgal classes, depicts the major pathways of their biosynthesis in microalgae, and discusses the prospects for microalgal LC-PUFA production.

Heterologous production of dihomo-gamma-linolenic acid in Saccharomyces cerevisiae

To make dihomo-gamma-linolenic acid (DGLA) (20:3n-6) in Saccharomyces cerevisiae, we introduced Kluyveromyces lactis Delta12 fatty acid desaturase, rat Delta6 fatty acid desaturase, and rat elongase genes. Because Fad2p is able to convert the endogenous oleic acid to linoleic acid, this allowed DGLA biosynthesis without the need to supply exogenous fatty acids on the media. Medium composition, cultivation temperature, and incubation time were examined to improve the yield of DGLA. Fatty acid content was increased by changing the medium from a standard synthetic dropout medium to a nitrogen-limited minimal medium (NSD). Production of DGLA was higher in the cells grown at 15 degrees C than in those grown at 20 degrees C, and no DGLA production was observed in the cells grown at 30 degrees C. In NSD at 15 degrees C, fatty acid content increased up until day 7 and decreased after day 10. When the cells were grown in NSD for 7 days at 15 degrees C, the yield of DGLA reached 2.19 microg/mg of cells (dry weight) and the composition of DGLA to total fatty acids was 2.74%. To our knowledge, this is the first report describing the production of polyunsaturated fatty acids in S. cerevisiae without supplying the exogenous fatty acids.

Improved arachidonic acids production from the fungus Mortierella alpina by glutamate supplementation

The effect of various concentrations of glutamate on arachidonic acid (AA) production from Mortierella alpina in shaker flask culture was studied. Glutamate supplementation promoted Mortierella growth, accelerated substrate metabolism, and increased AA production, and a concentration of 0.8 g/l glutamate resulted in the greatest AA yield (1.41 g/l). In 10 l airlift stirred fermenter culture, AA yield in the cultures exposed to 0.8 g/l glutamate was also greater than that in the control (0.56 g/l).

Effect of L-arginine-nitric oxide system on the metabolism of essential fatty acids in chemical-induced diabetes mellitus

Several studies have shown that the activities of delta-6-desaturase and delta-5-desaturase are depressed in experimental diabetes and in humans with insulin- and non-insulin-dependent diabetes mellitus (type I and type II diabetes mellitus respectively). Furthermore, treatment with insulin is known to correct the defects in desaturases in rats and humans with diabetes, especially in type I. In a recent study, we demonstrated that L-arginine and nitric oxide can prevent alloxan-induced beta cell damage, and the severity of diabetes, and restore the antioxidant status to near normal levels. But, no information is available as to the relationship between L-arginine-nitric oxide system and the metabolism of essential fatty acids in diabetes mellitus. In the present study, it was noted that the plasma levels of saturated fatty acids: stearic and palmitic were increased where as unsaturated fatty acids such as oleic, linoleic, gamma-linolenic and eicosapentaenoic acids (OA, LA, GLA and EPA respectively) were decreased in alloxan-induced diabetic rats. In the liver phospholipid (PL) fraction, GLA, DGLA (dihomo-GLA) and alpha-linolenic acid (ALA) were decreased in the alloxan-treated group; in the muscle PL fraction, LA, GLA and DGLA were low, whereas an increase in the saturated fatty acid content was noted. L-arginine (the precursor of nitric oxide) and sodium nitroprusside (a nitric oxide donor) treatment of alloxan-induced diabetic rats enhanced the levels of LA, GLA and DGLA. Further, nitric oxide synthase inhibitor, L-NMMA, prevented this beneficial action of L-arginine-nitric oxide system on essential fatty acid metabolism. The abnormalities in the essential fatty acid metabolism observed also reverted to normalcy following control of diabetes with insulin. These results indicate that nitric oxide can enhance the activities of delta-6- and delta-5 desaturases, which are depressed in diabetes, and suggests that there is a close interaction between L-arginine-nitric oxide system and the metabolism of essential fatty acids.

Essential fatty acids and cardiovascular disease: the Edinburgh Artery Study

The aim of this study was to determine whether plasma and red cell fatty acid levels were associated with cardiovascular disease, and whether any association was independent of other major risk factors. Over 1100 subjects were examined in a random sample survey of the general population (the Edinburgh Artery Study). Fatty acids were measured in three plasma fractions (triglyceride, cholesteryl ester and phospholipid) and in red cell phospholipids. Fatty acid levels in groups with cardiovascular disease (myocardial infarction (MI), angina and lower limb disease) were compared with a no disease group. In the cholesteryl ester and phospholipid fractions there were significantly lower levels of eicosapentaenoic acid in the MI group on univariate analysis (p<0.05), but not when adjusted for age, sex, smoking and systolic blood pressure using logistic regression. In the red cell fraction, alpha-linolenic acid was significantly lower in those with stroke (p<0.01) and lower limb disease (p<0.05). Linoleic acid was significantly raised in the triglyceride fraction in those with MI, probably reflecting recent dietary changes. There were significant increases in dihomo-gamma-linolenic acid in the phospholipid and red cell fractions in those with MI, and in the phospholipid fraction in the stroke group. These results do not support the hypothesis that n-6 fatty acids are protective against cardiovascular disease, although there may be some beneficial effects of the n-3 fatty acid, alpha-linolenic acid. Results from cross-sectional surveys must, however, be interpreted with caution because the presence of disease may affect dietary intake.

Antioxidant potential of evening primrose oil administration in hyperlipemic rabbits

The dietary intake of saturated fatty acids affects arteriosclerosis. We studied the effect of supplementation (15% wt/wt) of a hyperlipemic diet (1.33% cholesterol) with evening primrose oil (EPO) (Oenothera biennis) for 6 weeks in four groups of 10 rabbits each. At the end of this period we determined lipid peroxidation, glutathione content, and glutathione peroxidase, reductase and transferase activities in liver, brain, heart, aorta and platelets. The atherogenic diet increased tissue lipid peroxidation and decreased the protective antioxidant effect of glutathione. Dietary supplementation with EPO reduced tissue lipid peroxidation (61% in liver, 57% in brain, 42% in heart, 24% in aorta, 33% in platelets). Total glutathione was increased, especially in the aorta (90%) and platelets (200%); however, in all tissues the percentage of oxidised glutathione decreased. Evening primrose oil reduced glutathione peroxidase activity and increased the activities of glutathione reductase and transferase. We conclude that in rabbits made hyperlipemic with a diet rich in saturated fatty acids, EPO decreased tissue oxidative stress.

Enhancement of gamma-linolenic acid production by the fungus Mucor sp LB-54 by growth temperature

As a relatively prolific producer of GLA, the strain of Mucor sp LB-54 was selected for a study at different growth temperatures in shaker flask culture. The strain used in our experiment was capable to accumulate a relatively high amount of intracellular lipid, 20.73 % of dry cell weight, and GLA content of 15 % of total fatty acids after 5 days of incubation at 28°C. As the growth temperature was decreased from 28 to 12°C the percentage of GLA increased from 15 to 24 % of total fatty acids. In order to optimize the culture conditions for rapid biomass production and lipid production with a high proportion of GLA, the fungus was grown at two temperature combinations associated supplies of carbon source (glucose) in the culture medium. Maximal production of GLA (74 mg/l) was obtained from the Mucor sp LB-54 strain after 5 days of incubation at 28°C in basal medium following glucose addition (7 % w/v) and incubation for an additional 3 days at 12°C. The identity of GLA found in the strain of Mucor sp LB-54 was confirmed by the coupled gas chromatography-mass spectrometry

Essential fatty acid metabolism in long term primary cultures of rat cardiomyocytes: a beneficial effect of n-6:n-3 fatty acids supplementation

In long term (21 days) primary cultures of neonatal rat cardiomyocytes, utilized as a model of in vitro senescence, we investigated the dual effect of the time length in culture and of the supplementation with n-6:n-3 fatty acid mixtures on linoleic (LA) and alpha-linolenic acid (ALA) metabolism. Cardiomyocytes were divided into groups receiving: (1) control medium; (2) control medium plus n-3 fatty acids; (3) and (4) control medium plus n-6 and n-3 fatty acids in the ratio 1:2 or 2:1, respectively. In control cells. senescence caused a reduction in the conversion of LA and ALA, and the decrease in their metabolites was bypassed by the different supplementations. The fatty acid composition of cardiomyocyte lipids was therefore affected by both senescence and supplementation, as evidenced by the n-6:n-3 fatty acid ratio and the unsaturation index (U.I.) in cellular lipids. The final result of ageing in culture and of fatty acid supplementations was in all the groups of cells but one (n-6:n-3, 2:1) an unbalance in the n-6:n-3 fatty acid ratio. All the supplementations were able to counteract the decrease in the U.I. observed with senescence, but only the n-6:n-3 (2:1) was able to do so by increasing the cellular content of the fatty acids which are precursors of anti-aggregation eicosanoids without altering the n-6:n-3 fatty acid ratio.

The effects of cholesterol uptake from high-density lipoprotein subfractions on biliary sterol secretion in rats with essential fatty-acid deficiency

High-density lipoprotein (HDL) participates in the transfer of cholesterol to the liver, in which it is subsequently excreted into bile as bile acid and cholesterol. In this study, the effect of essential fatty-acid (EFA) deficiency on cholesterol contribution from HDL subfractions to bile was investigated. Rats that were rendered EFA-deficient over 4 weeks displayed changes in their plasma HDL subfractions and liver tissue fatty acids. Plasma linoleic (18:2n6), linolenic (18:3n3,) and arachidonic (20:4n6) acids decreased, whereas palmitoleic (16:1n7) and eicosatrienoic (20:3n9) acids increased. EFA deficiency was confirmed by an elevation of the 20:3(n-9)/20:4(n-6) index. To examine the hepatic handling of lipoprotein-derived cholesterol, HDL2 and HDL3 from donor rats were isolated, labeled with [14C]-cholesterol, and injected iv into EFA-deficient and normal rats with a bile fistula. In HDL subfractions from control rats, no significant variations were noted in the specific activity of cholesterol output in both groups of EFA recipient rats; however, the output of biliary bile acids was significantly decreased in EFA-deficient rats following the administration of labeled HDL3. In HDL2 and HDL3 originating from EFA-deficient rats, a decrease in the specific activity of both biliary cholesterol and bile acid output was recorded in EFA-deficient rats. Concomitant with the defective HDL2- and HDL3-[14C] cholesterol translocation into bile of EFA-deficient rats, increased hepatic very-low-density lipoprotein (VLDL)-[14C] cholesterol secretion was observed in vivo. HDL2 and HDL3 particles, derived from EFA-deficient rats, had an altered composition including a depletion in apo A-I and an enrichment in apo E isoforms, which are the the two major HDL apolipoproteins involved in the delivery of cholesterol to the liver. Taken together, these results show that normal EFA status is necessary for efficient HDL-cholesterol processing by the liver.

Dietary effect of a symmetrical triacylglycerol, 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol, on fatty acid composition of guinea pigs

The dietary effect of 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol (STG) on the fatty acid composition of guinea pigs was examined and compared with that of an eicosapentaenoic acid ethyl ester (EPA-E) and of a soybean oil (SBO) diet. In terms of content of plasma lipid, EPA-E had a greater hypolipidemic effect than STG. On the other hand, in terms of EPA incorporation, contents of EPA in liver lipid were almost the same in the STG and EPA-E groups. Considering that the amount of EPA administered in the EPA-E group was almost 1.5 times that of the STG group, EPA may be absorbed more effectively as the glycerol ester than as the ethyl ester in guinea pigs. In all the tissue lipids, the STG group had a higher unsaturation index (UI) than the EPA-E group even though there is a lower UI in the STG diet than the EPA-E diet. These results suggest that greater amounts of desaturase products as a whole were synthesized in the STG group than in the other two groups. The dihomo-gamma-linolenic acid/arachidonic acid (DGLA/AA) ratio in plasma total lipids in the STG group was 3.5 times that of SBO group, and the DGLA/AA ratio in the EPA-E group was half that of the SBO group. In liver lipid, the ratios of DGLA/AA and EPA/AA in the STG group were 0.687 and 0.488 (phosphatidylcholine fraction) and 0.237 and 0.752 (phosphatidylethanolamine fraction), respectively. The ratio of DGLA/AA as well as the high EPA/AA ratio obtained in the present study with the STG diet may lead to physiological alterations, including enhanced synthesis of 1- and 3-series eicosanoids.

Metabolism of linoleic and alpha-linolenic acids in cultured cardiomyocytes: effect of different N-6 and N-3 fatty acid supplementation

The metabolites of linoleic (LA) and alpha-linolenic (ALA) acids are involved in coronary heart disease. Both n-6 and n-3 essential fatty acids (EFAs) are likely to be important in prevention of atherosclerosis since the common risk factors are associated with their reduced 6-desaturation. We previously demonstrated the ability of heart tissue to desaturate LA. In this study we examined the ability of cultured cardiomyocytes to metabolize both LA and ALA in vivo, in the absence and in the presence of gamma linolenic acid (GLA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) alone or combined together. In control conditions, about 25% or LA and about 90% of ALA were converted in PUFAs. GLA supplementation had no influence on LA conversion to more unsaturated fatty acids, while the addition of n-3 fatty acids, alone or combined together, significantly decreased the formation of interconversion products from LA. Using the combination of n-6 and n-3 PUFAs, GLA seemed to counterbalance partially the inhibitory effect of EPA and DHA on LA desaturation/elongation. The conversion of ALA to more unsaturated metabolites was greatly affected by GLA supplementation. Each supplemented fatty acid was incorporated to a significant extent into cardiomyocyte lipids, as revealed by gas chromatographic analysis. The n-6/n-3 fatty acid ratio was greatly influenced by the different supplementations; the ratio in GLA+EPA+DHA supplemented cardiomyocytes was the most similar to that recorded in control cardiomyocytes. Since important risk factors for coronary disease may be associated with reduced 6-desaturation of the parent EFAs, administration of n-6 or n-3 EFA metabolites alone could cause undesirable effects. Since they appear to have different and synergistic roles, only combined treatment with both n-6 and n-3 metabolites is likely to achieve optimum results.

Abnormal membrane concentrations of 20 and 22-carbon essential fatty acids: a common link between risk factors and coronary and peripheral vascular disease?

Although elevated levels of cholesterol are associated with increased risks of coronary and peripheral vascular disease, the association frequently fails to provide a causative explanation at the individual level. New hypotheses are required which, whether or not they are correct, will provide new lines of research. It is proposed here that the causes of vascular disease are abnormal membrane phospholipid concentrations of the 20-carbon and 22-carbon essential fatty acids (EFAs) of the n-6 and n-3 series. These levels become abnormal with ageing, with stress and in response to smoking, high cholesterol levels and high saturated fat intakes. They are also abnormal in patients with diabetes and hypertension. The effects of these EFAs and their metabolites include lowering of triglycerides, elevation of high-density lipoprotein (HDL)-cholesterol, reduction of blood pressure, vasodilatation, reduction of fibrinogen levels and inhibition of platelet aggregation and of cardiac arrhythmias. Prospective studies have shown that abnormal levels of these fatty acids are predictive of future coronary death. Controlled trials of treatment have demonstrated that provision of the fatty acids reduces both coronary and total mortality. Further experimental and clinical investigations of the roles of appropriate membrane concentrations of these fatty acids are justified.

Dietary gamma-linolenic acid modulates macrophage-vascular smooth muscle cell interactions. Evidence for a macrophage-derived soluble factor that downregulates DNA synthesis in smooth muscle cells

Macrophages and smooth muscle cells (SMCs) are two of the major reactive cell types in atherosclerosis, a disease characterized by uncontrolled proliferation of SMCs. The present study was designed to determine how dietary oils containing gamma-linolenic acid (GLA) (primrose oil [PO]) and long-chain n-3 fatty acids (fish oil) influence the ability of macrophages to modulate SMC DNA synthesis in vitro. Mice were fed one of four diets containing 10% (wt/wt) corn oil (CO), PO, fish oil-CO mix (FC; 9:1, wt/wt), or fish oil-PO mix (FP; 1:3, wt/wt) for 2 weeks. Resident peritoneal macrophages were isolated from these mice and seeded on a semipermeable membrane with a 30-kDa cutoff. Macrophages were preincubated with or without 50 mumol/L indomethacin (a cyclooxygenase inhibitor) or 50 mumol/L L655,238 (a 5-lipoxygenase inhibitor) for 30 minutes and subsequently cocultured with naive murine aortic SMCs grown on culture dishes. DNA synthesis in SMCs and prostaglandin formation in coculture supernatants were measured at the end of a 39-hour incubation period. SMC DNA synthesis was inhibited by 28% and 60% in PO and FP diets containing 10.1% and 8.2% GLA, respectively, relative to the control CO diet containing no GLA or long-chain n-3 fatty acid. A fourfold increase in the levels of PGE1, a potent antiproliferative eicosanoid derived from GLA, was observed in the PO and FP groups relative to the control CO group.(ABSTRACT TRUNCATED AT 250 WORDS)

Essential fatty acid metabolism in patients with essential hypertension, diabetes mellitus and coronary heart disease

Mortality and morbidity from coronary heart disease (CHD), diabetes mellitus (DM) and essential hypertension (HTN) are higher in people of South Asian descent than in other groups. There is evidence to believe that essential fatty acids (EFAs) and their metabolites may have a role in the pathobiology of CHD, DM and HTN. Fatty acid analysis of the plasma phospholipid fraction revealed that in CHD the levels of gamma-linolenic acid (GLA), arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are low, in patients with HTN linoleic acid (LA) and AA are low, and in patients with non-insulin dependent diabetes mellitus (NIDDM) and diabetic nephropathy the levels of dihomo-gamma-linolenic acid (DGLA), AA, alpha-linolenic acid (ALA) and DHA are low, all compared to normal controls. These results are interesting since DGLA, AA and EPA form precursors to prostaglandin E1, (PGE1), prostacyclin (PGI2), and PGI3, which are potent platelet anti-aggregators and vasodilators and can prevent thrombosis and atherosclerosis. Further, the levels of lipid peroxides were found to be high in patients with CHD, HTN, NIDDM and diabetic nephropathy. These results suggest that increased formation of lipid peroxides and an alteration in the metabolism of EFAs are closely associated with CHD, HTN and NIDDM in Indians.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise-induced changes in the concentration of individual fatty acids and triacylglycerols of human plasma

Nineteen male handball players played for two 30-minute periods with a 10-minute interval. Blood samples were drawn at rest, at halftime, and at the end of the game. A biopsy of subcutaneous fat was also taken from 14 participants. Mean plasma lactate concentration was not greater than 4 mmol/L at the end of either half. The concentration of nonesterified fatty acids (NEFA) in plasma increased gradually but not uniformly throughout the game. In effect, the percentages of the major NEFA were significantly different at the three time points of sampling: palmitate (16:0) and stearate (18:0) decreased and oleate (18:1) and linoleate (18:2) increased, resulting in an increase of the ratio of unsaturated to saturated fatty acids (U/S) from 1.1 at rest to 1.6 at the end. The concentration of plasma triacylglycerols (TG) declined during the game, but nine of 19 subjects showed increases during one or both halves, implying a stimulation of TG release from the liver during exercise, which can, at times, overcome the increased hydrolysis of TG in muscle capillaries. Changes in the acyl-group distribution of plasma TG were minor but also in favor of unsaturated fatty acids. Changes in NEFA composition tended toward the composition of adipose tissue, in which TG had a U/S ratio of 3.2. Linear regression between changes in the total concentration of plasma NEFA during each half of the game and corresponding changes in the concentration of individual NEFA showed that the contributions (slopes) of myristate (14:0), palmitoleate (16:1), 18:0, and 18:2 were not significantly different from their fractions in adipose tissue TG.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between plasma essential fatty acids and smoking, serum lipids, blood pressure and haemostatic and rheological factors

We aimed to determine whether levels of plasma fatty acids are correlated with other potential risk factors for cardiovascular disease, using a sample of patients from a cross-sectional survey of the general population, in the City of Edinburgh. 306 men and women aged 55-74 years of whom half had clinical evidence of arterial disease were tested. The main outcome measures were plasma fatty acids and potential risk factors for cardiovascular disease (age, sex, smoking, blood pressure, serum cholesterol, HDL cholesterol (HDL-C), triglycerides (TGs), lipid peroxides (LPx), plasma fibrinogen, von-Willebrand factor (vWf), beta-thromboglobulin (beta TG), cross-linked fibrin degradation products (FIBDP) and plasminogen activator inhibitor PAI). High levels of several known risk factors for cardiovascular diseases were associated with low levels of certain essential fatty acids. Eicosapentaenoic (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) were negatively associated with smoking and TG levels. High levels of certain haemostatic factors, including plasma fibrinogen, blood viscosity and LPx were also associated with low levels of EPA, DHA, AA and HDL-C. In conclusion, plasma fatty acids show strong correlations with many potential risk factors for cardiovascular disease, emphasising their possible importance in pathogenesis.

Plasma essential fatty acids, cigarette smoking, and dietary antioxidants in peripheral arterial disease. A population-based case-control study

The aim of this study was to determine the levels of plasma fatty acids in patients with peripheral arterial disease and in control subjects and to identify whether any risks of disease related to these differences were influenced by smoking and antioxidant intake. A random sample of 1592 men and women aged 55 to 74 years was selected from the general population (the Edinburgh Artery Study), from which 153 cases of peripheral arterial disease were identified by the presence of intermittent claudication and low ankle systolic pressures at rest and during reactive hyperemia; these were matched by age and sex to 153 control subjects with no evidence of cardiovascular disease. In 113 case and 122 control subjects, fatty acid levels were measured in three plasma fractions (triglyceride, cholesteryl ester, and phospholipid), and smoking habits and dietary antioxidant intake were determined by questionnaire. Arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid (DPA/n-3) were significantly lower in the cases than controls (P < .01). More case than control subjects were current or exsmokers (86% versus 50%; P < .001), and the case subjects had lower vitamin C intake (64.8 mg versus 71.1 mg; P < .05). By logistic regression adjustment for smoking and vitamin C intake, only DPA/n-3 (odds ratio, 0.19; P < .01) and arachidonic acid (odds ratio, 0.44; P < .05) remained significantly related to disease; only DPA/n-3 reduced the risk associated with smoking. We conclude that in subjects with peripheral arterial disease compared with healthy control subjects, the largest differences occurred in fatty acids of the n-3 series, particularly DPA/n-3.(ABSTRACT TRUNCATED AT 250 WORDS)